Composition Vendor Newgen KnowledgeWorks (P) Ltd. PLoS One plos plosone PLOS One 1932-6203 Public Library of Science San Francisco, CA USA 10.1371/journal.pone.0327600 PONE-D-24-54978 Research Article Medicine and health sciencesEpidemiologyPandemics Medicine and health sciencesMedical conditionsInfectious diseasesViral diseasesCOVID 19 Medicine and health sciencesMental health and psychiatry Medicine and health sciencesPublic and occupational healthPhysical activity Biology and life sciencesNutritionDietAlcohol consumption Medicine and health sciencesNutritionDietAlcohol consumption Biology and life sciencesPsychologyBehaviorSedentary behavior Social sciencesPsychologyBehaviorSedentary behavior People and placesGeographical locationsEuropeEuropean UnionSweden Medicine and health sciencesPublic and occupational healthPhysical activityPhysical fitnessExercise Medicine and health sciencesSports and exercise medicineExercise Biology and life sciencesSports scienceSports and exercise medicineExercise Health aspects and lifestyle of licensed manual therapists during the COVID-19 pandemic in Sweden: The CAMP cohort study Health and lifestyle of manual therapists in Sweden during the COVID-19 pandemic https://orcid.org/0000-0001-5251-5995 Axén Iben Conceptualization Data curation Formal analysis Funding acquisition Investigation Methodology Project administration Resources Supervision Writing – original draft Writing – review & editing 1 2 https://orcid.org/0000-0002-1814-020X Weiss Nathan Conceptualization Data curation Formal analysis Funding acquisition Investigation Methodology Project administration Writing – original draft Writing – review & editing 1 3 * Skillgate Eva Conceptualization Data curation Formal analysis Funding acquisition Investigation Methodology Project administration Resources Supervision Writing – original draft Writing – review & editing 1 3 4 Unit of Intervention and Implementation Research for Worker Health, Institute of Environmental Medicine, Karolinska Institutet, Stockholm, Sweden Et liv i bevegelse (ELIB), Oslo, Norway Department of Health Promotion Science, Musculoskeletal & Sports Injury Epidemiology Center, Sophiahemmet University, Stockholm, Sweden Naprapathögskolan-Scandinavian College of Naprapathic Manual Medicine, Stockholm, Sweden Kelly Laura Hannah Editor Public Library of Science, UNITED KINGDOM OF GREAT BRITAIN AND NORTHERN IRELAND * E-mail: Nathan.weiss@shh.se

The authors have declared that no competing interests exist.

☯ These authors contributed equally to this work.

 7102025 2025 20 10 e0327600 10122024 1772025 2025 Axén et al This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Background

This study assessed health and change in lifestyle factors in Swedish manual therapists during one year of the COVID-19 pandemic, and potential differences with regards to age, sex, and business constellation. Further, therapists’ strategies for health promotion during the pandemic were explored.

 Methods

In this cohort study, 816 clinically active manual therapists were followed with web-based surveys during a year of the COVID-19 pandemic in Sweden, measuring physical activity, sedentary time, COVID-19-related worries, maladaptive coping, alcohol and tobacco consumption. Health promotion and impact of the pandemic on physical and mental health were explored in free text questions. Generalized estimating equations were conducted to assess changes in sample averages over time, and qualitative content analysis was used to code and categorize free-text answers.

 Results

There was a decrease in physical activity and sedentary time increased as well as subjective mental health impact by the pandemic over one year. Maladaptive coping decreased during follow-up, and alcohol and tobacco consumption decreased in younger participants, and women, respectively. Participants stated that the pandemic affected their physical and mental health and reported using health promoting activities primarily targeting physical activity, nutrition, and sleep.

 Conclusion

Swedish manual therapists maintained good lifestyle habits except for a small decrease in physical activity and slight increase in sedentary behavior and subjective mental health impact by the pandemic over time. There were small differences in terms of maladaptive coping, alcohol consumption, and tobacco consumption, however, these differences were not likely clinically relevant. The therapists seemed conscientious regarding health promotion measures during one year of the COVID-19 pandemic.

 http://dx.doi.org/10.13039/501100002706 AFA Försäkring 200140 http://dx.doi.org/10.13039/501100023454 Svenska Naprapatförbundet https://orcid.org/0000-0002-1814-020X WeissNathan This research was supported by: IA: AFA Insurance grant number 200140 https://www.afaforsakring.se/ NW: The Swedish Naprapathic Association (no grant number). https://naprapater.se/. The funders did not play any role in the study design, data collection and analysis, decision to publish, or preparation of the manuscript. Data Availability Due to ethical restrictions of disclosing personal and sensitive data in accordance with the protocol approved by the Swedish Ethical Review Authority, authors have to seek permission to allow us to make the data used in this study available. Data will be available upon request after permission is granted from the Swedish Ethical Review Authority. Inquiries for data access should be sent to the Ethical Review Authority, whose contact is registrator@etikprovning.se for permission to openly share the data. Outbreaks COVID-19 Introduction

The outbreak of the COVID-19 pandemic in 2020 [1] led to unprecedented public health consequences all over the world, not only in terms of disease and death, and the severe impact on health care systems, but also in the way other aspects of peoples’ lives were affected. To stop viral spread, many countries enforced lockdowns, where nothing but essential societal functions were running. Some changes were that we learned to work and study from home, to avoid social interaction outside the family, to shop online, and we stopped traveling.

Sweden chose a different route: instead of lockdowns, personal responsibility in minimizing viral spread was emphasized [2]. The authorities asked for social distancing, hand hygiene and self-isolation when experiencing symptoms. Recommendations included working from home and avoiding public gatherings. It was hypothesized that voluntary compliance would be more sustainable than controlling strategies [3]. If this different route was successful or not is not known, but compared to many European countries, Sweden’s excess mortality rate turned out lower between 2020 and 2021 [4]. Sweden’s vaccination program against COVID-19 were initiated in the end of 2020 and was implemented in stages depending on risk status. Elderly people and frontline healthcare workers were among the first groups that received the vaccine, and thereafter it was progressively made available for other groups in the population based on age and pre-existing conditions. By November 2021, 85% of the adult population in Sweden had received their first dose [5].

As part of Sweden’s COVID-19 strategy, licensed manual therapists were allowed to stay in business during the pandemic in Sweden. Manual therapists, licensed chiropractors and naprapaths, treat and prevent musculoskeletal conditions, which are prevalent conditions worldwide [6]. However, manual therapists mainly work with their hands in close proximity to the patient, which may led to a challenging work environment during the pandemic; having to balance patients’ needs with infection control measures, such as social distancing.

Previous studies have examined the impact of lockdowns on people’s health due to concerns that being confined to the home would lead to a more sedentary lifestyle and possibly poorer lifestyle choices [7]. Financial instability, fear of infection and the unpredictable situation led to poor mental health in some countries [8], while in Sweden, measures of mental health remained stable over time in a general population sample of adults [9].

The physical and mental health of healthcare personnel, particularly those dealing with COVID-infected patients, have been investigated. In qualitative studies, fear was a common experience [10] but also coping with the situation and adapting to change [11,12]. Manual therapists’ coping responses to the pandemic have been studied in countries of lockdown [13,14]. These studies described measures taken by manual therapists to provide safe care to patients under the circumstances. One study of US chiropractors reported high levels of stress [15]. However, studies from the Swedish context are missing.

The aim of this study was to assess health and changes in lifestyle in manual therapists during one year of the COVID-19 pandemic in Sweden, and potential differences with regards to age, sex, and business constellation. Further, the aim was to explore therapists’ strategies to promote their own health during the COVID-19 pandemic.

 Materials and methods Study design

This study was of mixed methods design and based on the Corona And Manual Professions (CAMP) cohort study, ClinicalTrials register identifier: NCT04834583. The study was approved by the Swedish Ethical Review Authority (Dnr 2020–03836).

Extensive details regarding the recruitment and data collection procedures of the CAMP cohort study have been published previously [16] and are described briefly below.

 Participants

Clinically active chiropractors and naprapaths, licensed by the National Board of Health and Welfare in Sweden, and those undergoing licensing practice were invited to participate, and 816 manual therapists were included.

 Data collection

Participants were recruited from November 1st 2020 through January 1st, and were thereafter followed prospectively during a one-year period (at 3-, 6-, and 12-months).

Informed consent was provided by all participants on the first page of the web-based baseline survey. Before being able to answer the baseline survey, participants were presented with information about the study and had to answer yes to the following statement: “I have understood what participation in this research study means, and consent to participating”.

 Variables Physical activity.

Physical activity (PA) was assessed with two questions adopted form the Swedish national public health survey (NBHWA-PA questions) [17,18] at baseline and at the 12-month follow-up. Participants were asked how many minutes they committed to physical exercise in a normal week (e.g., running, fitness training, ball sports), and everyday PA (e.g., walking, cycling, gardening) with the following answer alternatives: “0 minutes/no time”, “1-30 minutes”, “30-60 minutes”, “60-90 minutes”, “90-120 minutes”, and “More than 120 minutes”. The categorical response alternatives were converted using the middle value in each category, e.g., 30–60 minutes were converted to 45 minutes. Further, each participant’s ‘total physical activity’ per week was calculated by summarizing their physical exercise multiplied with 2 (to account for the higher intensity of PA), and their minutes of everyday PA, a measure which has previously shown moderate concurrent validity with accelerometer PA [19].

 Sedentary time.

Sedentary time was assessed at baseline and at 12-month of follow-up with SED-GIH, a single item question concerning the number of hours per day participants were sedentary, aside from sleeping, with the following answer alternatives: “Most of the day”, “13-15 hours”, “10-12 hours”, “7-9 hours”, “4-6 hours”, and “1-3 hours” [20]. The categorical response alternatives were converted using the middle value in each category, e.g., 7–9 hours equated to 8 hours of sedentary time per day. The SED-GIH has previously displayed acceptable convergent validity [17].

 Impaired sleep.

To assess impaired sleep, the following questions were used at baseline and at 12 months of follow-up: “Do you have difficulties falling asleep?”, “Do you wake up several times during the night and have difficulties falling asleep again?”, and “Do you feel very tired during worktime/daily activities?”. The answer alternatives were: “never”, “rarely/a few times per year”, “a few times per month”, “several times a week”, “always/every day”. The first two questions were adopted from the Karolinska Sleep Questionnaire [21], and the last from the unwinding and recovery questions by Aronsson et al. [22]. Impaired sleep was defined as having difficulty initiating sleep and/or difficulty maintaining sleep accompanied by daytime consequences “several times a week” or “always/every day” [23].

 Tobacco and alcohol use.

Tobacco consumption was measured by asking the participants the following questions at baseline and 12 months of follow-up: “Do you smoke daily?” and “Do you use snus daily?” with the answer alternatives: “Yes” or “No”. Participants having answered Yes to any or both questions were categorized as being regular tobacco users.

The AUDIT-C is a three-item alcohol screening tool used to assess harmful consumption of alcohol [24], consisting of the following questions asked at baseline and the 12-month follow-up: “how often do you have a drink of alcohol?” (never, monthly, 2–4 times a month, 2–3 times a week, 4 or more times a week), “how many standard drinks containing alcohol do you have on a typical day?” (1 or 2, 3 or 4, 5 or 6, 7–9, 10 or more), and “how often do you have four (woman), or five (man) or more drinks on one occasion?” (never, less than monthly, monthly, weekly, daily or almost daily). The AUDIT-C generates a score between 0–12.

 Maladaptive coping.

To investigate participants’ strategies to cope with different stressors, a Swedish version of the Brief COPE questionnaire was used at baseline and 12 months of follow-up [25]. The questionnaire consists of 28 statements divided into 14 subscales: self-blame, self-distraction, active coping, denial, use of emotional support, use of instrumental support, substance use, behavioral disengagement, venting, positive reframing, planning, humor, acceptance, and religion. Respondents rated each statement on a 4-point Likert scale, ranging from 1 “I haven’t been doing this at all” to 4 “I have been doing this a lot” [26]. The 14 subscales are further divided into adaptive and maladaptive coping, with venting, denial, substance use, behavioral disengagement, self-distraction, and self-blame classified as maladaptive with a continuous total score ranging from 12 to 48 [27,28].

 COVID-19-related worries.

Worries relating to the pandemic were asked at 6- and 12-months of follow-up. The COVID-19 Worry Scale (CWS) consists of seven items regarding participants’ worry about COVID-19 infection; concerns about themselves, their family, and friends being affected by COVID-19, answered on a 4-point Likert scale ranging from 1 (not at all) to 4 (very much), with a total score ranging from 7 to 28 [29]. The CWS has demonstrated adequate psychometric properties [30,31]. In addition to the CWS, two additional questions were asked regarding potential worries experienced by clinically active manual therapists amidst the COVID-19 pandemic: “How worried have you been of infecting patients/clients?” and “Have you experienced worries related to your clinical practice as a chiropractor/naprapath with relation to the COVID-19 pandemic?” with the same answer alternatives. Further, a free-text question was also added, asking participants to list the three largest worries related to their clinical practice and the COVID-19 pandemic with 6 months recall time: “List the three main worries related to your clinical practice and the COVID-19 pandemic”. In the beginning of the section regarding COVID-19-related worries, it was specified that the questions related to the past six months.

 Subjective health impact by the COVID-19 pandemic.

Participants were asked about their subjective physical and mental health and the COVID-19 pandemic at baseline and after 12 months of follow-up: “Has your physical health been impacted by the COVID-19 pandemic?” and “Has your mental health been impacted by the COVID-19 pandemic?” with the answer alternatives “Yes, very negative”, “Yes, negative”, “No, not at all”, “Yes, positive”, “Yes, very positive”. Those answering “Yes”, in either negative or positive direction received a separate follow-up question on how their impacted physical and/or mental health changed the possibility to carry out clinical work, with the same answer alternatives.

Additionally, those answering “Yes” in either positive or negative direction to the questions described above had the possibility to deepen their answer in free text. At baseline, the questions were: “Comments regarding how the COVID-19 impacted your physical health”, “Comments regarding how the COVID-19 impacted your mental health”, “Comments regarding how your impacted physical health due to the COVID-19 pandemic affected your work ability”, and “Comments regarding how your impacted mental health due to the COVID-19 pandemic affected your work ability”. At the 12-month follow-up, the questions were: “Comments regarding how the COVID-19 impacted your physical health the last six months”, “Comments regarding how the COVID-19 impacted your mental health the last six months”, “Comments regarding how your impacted physical health due to the COVID-19 pandemic affected your work ability the last six months”, and “Comments regarding how your impacted mental health due to the COVID-19 pandemic affected your work ability the last six months”.

 Free text variables.

Participants had the opportunity to express their experiences freely in several free text questions and statements concerning their health, lifestyle and the COVID-19 pandemic. Apart from those regarding COVID-19-related worries and subjective health impact by the COVID-19 pandemic described above, participants were asked the following question at baseline: “What have you done to promote your own health during the COVID-19 pandemic?”, and “What have you done to promote your own health the past six months?” at the 12-month follow-up.

 Statistical analysis

Descriptive statistics were computed for participant baseline characteristics with continuous variables presented as mean and standard deviation (SD), and categorical variables as frequencies and percentages. Generalized Estimating Equations (GEE) with exchangeable correlation matrix was used to study changes in the sample average for physical activity, sedentary time, maladaptive coping strategies, COVID-19-related worries, impaired sleep, tobacco and alcohol use, and subjective health impact by the COVID-19 pandemic over time. Separate models were conducted for each variable over the follow-up period, and stratified analyses were conducted based on sex (male/female), median age (≤ 34 years/ > 34 years), and business constellation (working alone/with few or with many colleagues) with the addition of an interaction term between group and time to study the change in the trajectory slope over time between the groups. Statistical analyses were carried out in R version 4.1.4, GEE was conducted with the ‘geepack’ package [32] for continuous and nominal scale data, and the ‘multgee’ package [33] was used for ordinal data. Furthermore, a qualitative content analysis was used to code and categorize participants’ data from free-text answers [34]. The answers were read through twice by two of the authors (NW, IA) to get an overview of the content. The text was thereafter condensed into meaning units and later coded based on discussion within the research group. Subcategories, categories, and themes were formed, and counts of each subcategory were calculated.

 Results

A total of 850 participants of 1718 eligible agreed to participate in the study. Thirty-four participants were excluded due to not providing information regarding one of the eligibility criteria (being clinically active or not), resulting in a study sample of 816, and a response proportion of 47%. Over the course of the study, 36 participants withdrew their participation, and the response rate at the follow-up surveys was around 80% (Fig 1).

10.1371/journal.pone.0327600.g001 Study flow chart.

Number of participants invited, agreeing to participate, excluded or withdrawing from the study, and answering at each time-point.

Baseline characteristics of the study sample are presented in Table 1. The mean age of the sample was 44 years, and 46% were women. The proportion of naprapaths and chiropractors amounted to 68% and 32% respectively. In total, 22% of the participants reported working alone.

10.1371/journal.pone.0327600.t001Baseline characteristics of study participants.
Variable na Total
Age, mean (SD) 816 44 (11.2)
Sex, n (%) 816
 Male 441 (54)
 Female 375 (46)
Occupation, n (%) 816
 Licensed Naprapath 508 (62)
 Licensed Chiropractor 257 (31)
 Naprapath undergoing licensing practice 46 (6)
 Chiropractor undergoing licensing practice 5 (1)
Number of hours clinically active/week previous 3 months, mean (SD) 809 28.3 (11.4)
Other employment, n (%) 813 175 (22)
Business owner, n (%) 746 557 (75)
Business constellation (working alone), n (%) 810 175 (22)

aNumber of participants answering the question. SD, standard deviation.

 Longitudinal lifestyle patterns

Longitudinal lifestyle behaviors among the participants during a year are presented in Tables 2–4, for the whole sample, and stratified by sex, median age, and business constellation.

10.1371/journal.pone.0327600.t002Physical activity and sedentary time at baseline and the 12 months follow-up in all and stratified by sex, age, and business constellation.
All Women Men ≤ 34 years > 34 years Working alone Not working alone
Physical exercisea
 Mean min/week at baseline (95% CI) 89.8 (87.0, 92.6) 85.9 (81.6, 90.1) 93.2 (89.5, 96.8) 93.0 (89.2, 96.8) 86.8 (82.7, 90.8) 86.5 (81.6, 91.5) 91.7 (88.4, 95.1)
 Mean min/week at 12 months (95% CI) 84.5 (81.4, 87,6) 81.3 (76.7, 85.9) 87.3 (83.2, 91.5) 85.5 (81.0, 90.0) 83.5 (79.2, 87.8) 83.0 (77.7, 88.3) 85.6 (81.7, 89.4)
 Mean difference in physical exercise baseline to 12 months (95% CI) −5.3 (−7.9, −2.6) 1.27 (−4.1, 6.6) −4.3 (−9.5, 1.0) 6.5 (0.1, 13.0)
Everyday physical activityb
 Mean min/week at baseline (95% CI) 98 (95.7, 100.3) 101.0 (97.9, 104.1) 95.4 (92.2, 98,7) 100.5 (97.6, 103,5) 95.3 (91.8, 98,7) 100.2 (96.6, 103.9) 96.8 (93.9, 99.7)
 Mean min/week at 12 months (95% CI) 96.9 (94.4, 99,4) 98.7 (95.2, 102.1) 95.4 (91.9, 99.0) 99.0 (95.8, 102.2) 94.6 (90.6, 98.5) 96.1 (91.8, 100.3) 97.7 (94.6, 100.7)
 Mean difference in everday physical activity baseline to 12 months (95% CI) −1.05 (−3.5, 1.4) −2.3 (−7.3, 2.7) 0.9 (−4.2, 5.9) −4.6 (−10.8, 1.6)
Total physical activityc
 Mean min/week at baseline (95% CI) 277.6(271.2, 283.9) 273(263, 282) 282(273,290) 281(272,290) 274(265, 283) 273(262,284) 280(272,288)
 Mean min/week at 12 months (95% CI) 266.0(258.8, 273.2) 261(251, 272) 270(260, 280) 266(255,276) 266(256,276) 262(250,274) 269(260,278)
 Mean difference in total physical activity baseline to 12 months (95% CI) −11.5(−17.6,−5.5) 0.2(−12.1,12.5) −7.5(−19.8,4.8) 8.6(−5.3,22.4)
Sedentary timed
 Mean hours/day at baseline (95% CI) 4.3(4.1,4.4) 4.1(3.9, 4.4) 4.4(4.1, 4.6) 4.6(4.4, 4.8) 3.9(3.7, 4.2) 4.0(3.8,4.3) 4.4(4.2,4.6)
 Mean hours/day at 12 months (95% CI) 4.6(4.3,4.6) 4.3(4.0, 4.5) 4.6(4.3, 4.9) 4.9(4.6, 5.2) 4.1(3.8,4.3) 4.1(3.8,4.4) 4.7(4.4,4.9)
 Mean difference in sedentary time baseline to 12 months (95% CI) 0.2(0.0,0.4) −0.1(−0.4,0.3) 0.2(−0.2,0.5) −0.2(−0.6,0.1)

95% CI, 95% confidence interval.

aMinutes of physical exercise in a normal week (e.g., running, fitness training, ball sports).

bMinutes of everyday physical activity in a normal week (e.g., walking, cycling, gardening).

cSum of minutes of exercise per week multiplied by 2 (to account for the higher intensity of exercise) and minutes of daily activity per week.

dNumber of hours per day spent sedentary.

 10.1371/journal.pone.0327600.t003Psychological factors, impaired sleep, and subjective health impact by the pandemic at baseline and the 12-months follow-up in all and stratified by sex, age, and business constellation.
All Women Men ≤ 34 years > 34 years Working alone Not working alone
Maladaptive copinga
 Mean score at baseline (95% CI) 21.5(21.2,21.9) 22.7(22.3,23.1) 20.5(20.1,20.9) 21.8(21.4, 22.2) 21.3(20.8, 21.8) 21.1(20.5,21.6) 21.8(21.4,22.1)
 Mean score at 12 months (95% CI) 21.2(20.9,21.6) 22.4(21.9,22.8) 20.3(19.8,20.7) 21.5(21.0, 21.9 21.0(20.5,21.5) 20.9(20.3,21.4) 21.4(21.0,21.8)
 Mean difference in maladaptive coping from baseline to 12 months (95% CI) −0.3(−0.6,−0.0) −0.1(−0.7,0.4) −0.1(−0.6,0.6) −0.0(−0.8,0.7)
COVID-19 worry scaleb
 Mean score at 6 months (95% CI) 14(13.6,14.3) 14.6(14.2,15.1) 13.4(12.9,13.9) 14.2(13.7, 14.6) 13.8(13.3,14.3) 14.3(13.7,14.9) 13.8(13.4,14.2)
 Mean score 12 months (95% CI) 13.3(12.9,13.6) 14.0(13.6,14.5) 12.6(12.1,13.0) 13.2(12.8, 13.7) 13.2(12.8, 13.7) 13.7(13.1,14.3) 13.0(12.6,13.4)
 Mean difference in COVID-19 worry scale from baseline to 12 months (95% CI) −0.7(−0.9,−0.5) 0.3(−0.2,0.8) −0.4(−0.9,0.1) 0.1(−0.5,0.6)
Worry about infecting patientsc
 Mean score at 6 months (95% CI) 2.3(2.3,2.4) 2.6(2.5,2.6) 2.1(2.1,2.2) 2.4(2.3,2.5) 2.3(2.2,2.4) 2.3(2.3,2.4) 2.3(2.2,2.4)
 Mean score at 12 months (95% CI) 2.3(2.2,2.3) 2.5(2.4,2.6) 2.1(2.0,2.1) 2.3(2.2,2.4) 2.2(2.1,2.3) 2.3(2.1,2.4) 2.2(2.2,2.3)
 Mean difference in worry about infecting patients from 6 months to 12 months (95% CI) −0.1(−0.2,−0.0) 0.0(−0.1,0.1) −0.0(−0.2,0.1) 0.1(−0.1,0.2)
Worry about clinical practiced
 Mean score at 6 months (95% CI) 2.3(2.2,2.3) 2.5(2.4,2.6) 2.1(2.0,2.2) 2.3(2.2,2.4) 2.2(2.1,2.3) 2.3(2.1,2.4) 2.2(2.2,2.3)
 Mean score at 12 months (95% CI) 2.1(2.1,2.2) 2.3(2.2,2.4) 2.0(1.9,2.1) 2.2(2.1,2.3) 2.1(2.0,2.2) 2.2(2.1,2.3) 2.1(2.0,2.2)
 Mean difference in worry about clinical practice from 6 months to 12 months (95% CI) −0.1(−0.2,−0.0) −0.1(−0.2,0.1) 0.0(−0.1,0.2) 0.0(−0.2,0.2)
Impaired sleepe
 Proportion at baseline (95% CI) 0.09(0.07,0.11) 0.11(0.08,0.14) 0.07(0.04,0.09) 0.08(0.06, 0.11) 0.09(0.06,0.12) 0.12(0.07,0.17) 0.08(0.06,0.01)
 Proportion at 12 months (95% CI) 0.10(0.08,0.12) 0.12(0.08, 0.15) 0.09(0.06,0.11) 0.10(0.7,0.14) 0.10(0.07,0.13) 0.11(0.06,0.16) 0.10(0.07,0.12
 Mean difference in proportion of impaired sleep from baseline to 12 months (95% CI) 0.01(−0.01,0.04) −0.01(−0.06,0.04) 0.00(−0.04,0.06) −0.03(−0.10,0.04)
Subjective physical health impact by the COVID-19 pandemic
 Cumulative odds ratio from baseline to 12 months (95% CI)f 0.9(0.7,1.1) 1.2(0.8,1.9) 0.9 (0.6,1.3) 0.9(0.6,1.4)
Subjective mental health impact by the COVID-19 pandemic
 Cumulative odds ratio from baseline to 12 months (95% CI)f 0.5(0.4,0.6) 1.0(0.7,1.5) 0.7(0.5,1.0) 1.0(0.6,1.6)

95% CI, 95% confidence interval.

aSum score of maladaptive coping strategies of Brief COPE, items: 1, 3, 4, 6, 8, 9, 11, 13, 16, 19, 21, 26. Range 12–48.

bTotal score ranging 7–28.

cTotal score ranging 1–4.

dTotal score ranging 1–4.

eDifficulties falling asleep and waking up during the night in combination with daytime interference of activities several times a week or always/every day.

fOrdinal variable with categories: “Yes, very negative,” “Yes, negative,” “No, not at all,” “Yes, positive,” and “Yes, very positive.” Estimates represents the cumulative odds ratios for transitioning one step to a higher category over time (towards “Yes, very positive”), with “Yes, very negative” as the reference category.

 10.1371/journal.pone.0327600.t004Alcohol and tobacco consumption at baseline and the 12 months follow-up in all and stratified by sex, age, and business constellation.
All Women Men ≤ 34 years > 34 years Working alone Not working alone
AUDIT-Ca
 Mean risk score at baseline (95% CI) 3.1(3.0,3.2) 2.8(2.6,2.9) 3.4(2.2,3.6) 3.0(2.9,3.2) 3.2(3.1,3.4) 3.2(3.0,3.4) 3.1(2.9,3.2)
 Mean risk score at 12 months (95% CI) 3.1(3.0,3.2) 2.7,(2.6,2.8) 3.4(3.2,3.6) 2.9(2.7, 3.0) 3.3(3.1, 3.4) 3.1(2.9,3.3) 3.0(2.9,3.2)
 Mean difference in alcohol risk score from baseline to 12 months (95% CI) −0.0(−0.1,0.0) −0.1(−0.2, 0.1) −0.2(−0.4,−0.1) −0.0(−0.2,0.2)
Tobacco consumptionb
 Proportion at baseline months (95% CI) 0.16(0.13,0.19) 0.8(0.05,0.10) 0.23(0.19,0.27) 0.18(0.14,0.22) 0.14(0.110.17) 0.15(0.09,0.20) 0.16(0.13,0.19)
 Proportion 12 months (95% CI) 0.16(0.13,0.19) 0.06(0.03,0.08) 0.25(0.21,0.29) 0.17(0.13,0.21) 0.15(0.12,0.19) 0.16(0.10,0.22) 0.16(0.13,0.19)
 Mean difference in proportion of tobacco consumption from baseline to 12 months (95% CI) 0.00(−0.02,0.02) −0.04(−0.07,−0.00) −0.03(−0.07,0.01) 0.02(−0.02,0.06)

95% CI, 95% confidence interval.

aTotal score ranging 0–12.

bSmoking or using snus daily.

The change between baseline and the months follow-up in physical exercise, total physical activity, and sedentary time during the year for the whole study sample was −5 minutes (95% CI: −7.9, −2.6), −12 minutes (95% CI: −17.6, −5.5), and 0.2 hours (95% CI: 0.0, 0.4), respectively, see Table 2. Those working alone increased their physical exercise by 7 minutes (95% CI: 0.1, 13.0) compared to those not working alone, however, no differences in the trajectory slope of change between the other groups in the separate strata were observed.

The use of maladaptive coping strategies reduced during the follow-up period (−0.3, 95% CI: −0.6, −0.0), however, there were no differences between groups. COVID-19-related worries also reduced during the follow-up period (−0.7, 95% CI: −0.9, −0.5). So did worry about infecting patients (−0.1, 95% CI: −0.2, −0.0), and worry about clinical practice (−0.1, 95% CI: −0.2, −0.0), as seen in Table 3, without any clear differences between groups in the stratified analyses. There was no change in the proportion of participants with impaired sleep during the follow-up. Furthermore, there were lower odds of better subjective mental health impact by the pandemic (OR: 0.5, 95% CI: 0.4, 0.6), however, there were no differences between groups, see Table 3.

Risky scores of alcohol consumption did not change during the follow-up period in the entire group; however, participants below median age (34 years) reduced their alcohol consumption slightly while those older than median age (34 years) increased their alcohol consumption slightly during follow-up (difference in change: −0.2, 95% CI: −0.4, −0.0). Furthermore, the proportion of women regularly using tobacco decreased compared to males during follow-up (−0.04, 95% CI: −0.07, −0.00), see Table 4.

 Free text answers

All subcategories, categories, and themes emerging from the free text answers are presented in Supporting S1-S12 Tables in S1 File.

We asked: “What have you done to promote your own health during the COVID-19 pandemic?” At baseline, 664 individuals answered this question. Three overarching themes emerged: promoting physical health (including physical activity, nutrition, sleep, keeping routines and using alternative methods), promoting mental health (including health promotional activities, using the physical environment and handling stress) and adhering to the official recommendations. At the 12 months follow-up, 486 answers were retrieved, with very similar themes. However, at 12 months minimizing alcohol was mentioned as an action to promote physical health, and changing profession emerged as a new category, see Table 5.

10.1371/journal.pone.0327600.t005What have you done to promote your own health during the COVID-19 pandemic.
Baseline (n = 664a) 12-month follow-up (n = 486a)
Total count = 1645b Total count = 1026b
Category, number of counts (%)c Category, number of counts (%)c Theme
Engaging in exercise/physical activity, 508 (30.9) Engaging in exercise/physical activity, 432 (42.1) Activities promoting physical health
Ensuring good nutrition, 259 (15.7) Ensuring good nutrition/restricting alcohol, 205 (20.0)
Getting enough sleep, 101 (6.1) Getting enough sleep, 90 (8.8)
Keeping routines, 22 (1.3) Keeping routines, 23 (2.2)
Using alternative methods, 34 (2.1) Using alternative methods, 9 (0.9)
Engaging in health promotion, 69 (4.2) Engaging in health promotion, 79 (7.7) Activities promoting mental health
Using the physical environment to my advantage, 209 (12.7) Using the physical environment to my advantage, 49 (4.8)
Stress handling, 89 (5.4) Stress handling, 76 (7.4)
Change profession, 2 (0.2)
Recommendations, 354 (21.5) Recommendations, 61 (5.9) Adhering to recommendations

aNumber of participants answering the question.

bThe total number of codes categorized into different subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

Respondents were asked “How did the COVID-19 pandemic impact your physical health?” At baseline, 202 individuals reported themes relating to negative impact (such as worse physical condition and lifestyle, covid infection and other illnesses), changes due to the official recommendations (including change in exercise routines and social interaction), but 70 responses concerned themes relating to positive impact (including less infections and improved lifestyle). The 99 responses at 12 months follow-up gave no additional themes, see Table 6.

10.1371/journal.pone.0327600.t006Comments regarding how the COVID-19 pandemic impacted your physical health.
Baseline (n = 202a) 12-month follow-up (n = 99a)
Total counts = 342b Total counts = 147b
Category, number of counts (%)c Category, number of counts (%)c Theme
Worse physical condition, 111 (32.5) Worse physical condition, 33 (22.4) Negative impact
Worse lifestyle, 15 (4.4) Worse lifestyle, 8 (5.4)
Mental impact, 49 (14.3) Mental impact, 21 (14.3)
Covid and other infections, 47 (13.7) Covid and other infections, 34 (23.1)
Illness, 22 (6.4) Illness, 12 (8.2)
Less infections, 23 (6.7) Less infections, 5 (3.4) Positive impact
More exercise, 32 (9.4) More exercise, 15 (10.2)
Improved lifestyle, 15 (4.4) Improved lifestyle, 6 (4.1)
Changed exercise, 9 (2.6) Changed exercise, 2 (1.3) Changes due to official recommendations
Social distancing, 8 (2.3) Social distancing, 4 (2.7)
Less work, 8 (2.3) Less work, 6 (4.1)
More work, 3 (0.9) More work, 1 (0.7)

aNumber of participants answering the question.

bThe total number of codes categorized into different underlying subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

Respondents stating that their physical health was impacted by the COVID-19 pandemic, were asked “how did this impact your work ability”. At baseline, 74 individuals responded, with themes such as change in physical capacity and workload (both increased and decreased), as well as consequences such as long-covid, sickness absence and musculoskeletal pain. At the 12-month follow-up, 23 individuals answered this question with the same themes, see Table 7.

10.1371/journal.pone.0327600.t007Comments regarding how your impacted physical health due to the COVID-19 pandemic affected your work ability.
Baseline (n = 74a) 12-month follow-up (n = 23a)
Total count = 99b Total count = 34b
Category, number of counts (%)c Category, number of counts (%)c Theme
Decreased physical capacity, 22 (22.2) Decreased physical capacity, 1 (2.9) Change in physical capacity
Improved physical capacity, 13 (13.1) Improved physical capacity, 4 (11.8)
Increased workload, 14 (14.1) Increased workload, 13 (38.2) Change in workload
Decreased workload, 16 (16.2) Decreased workload, 5 (14.7)
Other consequences, 34 (34.3) Other consequences, 11 (32.4) Consequences of COVID-19

aNumber of participants answering the question.

bThe total number of codes categorized into different underlying subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

The question “How did COVID-19 impact your mental health?” yielded 305 responses at baseline. The resulting themes included mental ill-health, social consequences, worry (about COVID and work), but also 25 positive consequences were reported (such as more time with family). The last theme concerned double standards, where the respondents expressed a conflict between the official recommendations and their inability to follow these when working as manual therapists. At the 12-month follow-up, 135 answers were retrieved, and a new category was included in the mental ill-health theme: illness, see Table 8.

10.1371/journal.pone.0327600.t008Comments regarding how the COVID-19 pandemic impacted your mental health.
Baseline (n = 305a) 12-month follow-up (n = 135a)
Total number of counts = 598b Total number of counts = 205b
Category, number of counts (%)c Category, number of counts (%)c Theme
Mental ill-health, 207 (34.6) Mental ill-health, 61 (29.8)Illness, 5 (2.3) Mental ill-health
Social consequences, 63 (10.5) Social consequences, 20 (9.8) Social consequences
Limitations in leisure time, 12 (2.0) Limitations in leisure time, 5 (2.3)
Better mental health, 21 (3.5) Better mental health, 12 (5.9) Positive consequences
More time with family, 4 (0.7) More time with family, 1 (0.5)
Fear of COVID-19, 101 (16.9) Fear of COVID-19, 17 (8.3) COVID-19-related worry
General worry, 49 (8.2) General worry, 13 (6.3)
Influence on work, 11 (1.8) Influence on work, 16 (7.8) Work-related worry
Worry about work/economy, 124 (20.7) Worry about work/economy, 40 (19.5)
Conflict between work and official recommendations, 6 (1.0) Conflict between work and official recommendations, 15 (7.3) Double standards/moral

aNumber of participants answering the question.

bThe total number of codes categorized into different underlying subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

Respondents stating that their mental health was impacted by the COVID-19 pandemic, were asked “how did this impact your work ability”. As for physical health, both negative themes (anxiety, worry, and cognitive effects influencing work) and positive themes (less stress, more energy) consequences were recorded. At baseline, 43 individuals answered this question, and no new themes emerged from the 29 responses at 12 months, see Table 9.

10.1371/journal.pone.0327600.t009Comments regarding how your impacted mental health due to the COVID-19 pandemic affected your work ability.
Baseline (n = 43a) 12-month follow-up (n = 29a)
Total number of counts = 54b Total number of counts = 50b
Category, number of counts (%)c Category, number of counts (%)c Theme
Exhaustion/depression, 21 (38.9) Exhaustion/depression, 25 (50.0) Negative consequences on mental health
Worry/anxiety, 18 (33.3) Worry/anxiety, 4 (8.0)
Impact on work, 4 (7.4) Impact on work, 12 (24.0)
Cognitive consequences, 3 (5.6) Cognitive consequences, 3 (6.0)
Positive consequences, 8 (14.8) Positive consequences, 6 (12.0) Positive consequences on mental health

aNumber of participants answering the question.

bThe total number of codes categorized into different underlying subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

Participants who answered having experienced worries related to their clinical practice as a chiropractor/naprapath in relation to the COVID-19 pandemic to a small/moderate/large degree were asked to list the three main worries related to their clinical practice and the COVID-19 pandemic at the 6-month, and 12-month follow-up. The two themes emerging with categories having the highest count were “economic worry”, and “worry about infection” in relation to personal, colleagues’, and patients’ safety. Furthermore, themes related to existential worry, uncertainty about official recommendations, and a general concern for patients’ health also emerged, see Table 10.

10.1371/journal.pone.0327600.t010List the three main worries related to your clinical practice and the COVID-19 pandemic.
6-month follow-up (n = 373a) 12-month follow-up (n = 380a)
Total number of counts = 787b Total number of counts = 902b
Category, number of counts (%)c Category, number of counts (%)c Theme
Colleague safety, 2 (0.3) Colleague safety, 13 (1.4) Worry about infection
Patient safety, 22 (2.8) Patient safety, 22 (2.4)
Personal safety, 22 (2.8) Personal safety, 44 (4.9)
Worry about infection, 293 (37.2) Worry about infection, 247 (27.4)
Economic worry, 381 (48.4) Economic worry, 450 (49.9) Economic worry
Existential worry, 15 (1.9) Existential worry, 13 (0.3) Existential worry
Uncertainty about recommendations, 28 (3.6) Uncertainty about recommendations, 77 (8.5) Uncertainty about recommendations
Concern for patients’ health, 24 (3.0) Concern for patients’ health, 36 (4.0) Concern for patients’ health

aNumber of participants answering the question.

bThe total number of codes categorized into different underlying subcategories.

cEach participant’s response could generate several codes and contribute to multiple underlying subcategories forming each category. One category could therefore comprise a higher number of counts than the total number of participants answering the question. The percentage refers to the percentage of times a category was mentioned of the total number of counts.

 Discussion Summary of findings

In this study, we found that Swedish manual therapists rated their physical and mental health was impacted by the pandemic. There was a small decrease in physical activity and sedentary time increased slightly as well as subjective mental health impact by the pandemic over one year. Maladaptive coping strategies and COVID-19-related worries decreased during this time. Furthermore, there were small differences in changes over time between younger and older participants in alcohol consumption, and between women and men in tobacco consumption, however, none of the differences observed for coping, worries, as well as tobacco and alcohol consumption were likely clinically relevant.

The free-text answers, that deepened the understanding of what we aimed to study, also indicated no clear changes over time. The manual therapists made considerable effort in health promotion during the COVID-19 pandemic, as they clearly strived to keep physically healthy by addressing important lifestyle factors, physical activity, nutrition and sleep. Also, mental health was addressed using promotional activities such as physical activity, deliberate stress-handling, outdoor stay and social interaction (albeit different than pre-pandemic times).

 Discussion of findings

Several studies of health personnel during the pandemic found a high degree of stress and negative influence on mental health [10–12]. This is not surprising as this was a time of a heavy load on those caring for severely ill patients. Manual therapists in Sweden were not in the same caregiver category, but their work was still challenging as it cannot be carried out without getting close to the patient. We have reported on the mental and musculoskeletal health of this cohort previously, both which were found to be good [16] during the pandemic. Still, many of the issues reported in previous studies, such as stress, anxiety, and worry were also found in this group when we asked the participants to describe how they were affected.

One explanation for these stable and relatively good health outcomes is that our participants maintained good lifestyle habits and seemed conscientious regarding health promotion measures. Exercising, preferably outdoors, eating well, getting enough sleep and keeping in touch with family and friends may have contributed to these stable health outcomes.

Another explanation for our findings may be Sweden’s approach to not enforcing a lockdown. The participants in the study were clinically active manual therapists in the year of follow-up, and working is a well-known contributor to good health [35]. Furthermore, they were able to exercise outdoors, which was seen as a health-promoting activity, physically and mentally. Many participants also mentioned that they kept to their usual routines as much as possible in order to stay healthy. A parallel finding from Sweden is a study among university students, who also kept healthy lifestyle behaviors through the pandemic [36].

As the pandemic progressed, a new health issue emerged: worry. Around the world, students [37], minorities [38], as well as health care workers and non-health care essential workers [39] reported being worried in relation to the pandemic. They were worried about their families getting the virus, the safety of vaccines, lockdowns and governmental policies. In our study, we specifically asked manual therapists about worries relating to COVID-19 infection; concerns about themselves, their family, and friends being affected by COVID-19, as well as concerns about infecting patients. As Sweden did not enforce a lockdown, these were thought to be real concerns for a manual therapist seeing patients. However, the participants scored low on the CWS, both at 6- and 12-month follow-up. It may be that by these points in time (May/June 2021 and November/December 2021), having lived through the pandemic for a year and more, they knew what to expect, and were less worried. Several subcategories related to the COVID-19 vaccination emerged from the free-text questions. In the 6-month follow-up, a few of the therapists raised worries concerning being last of the healthcare workers being vaccinated. As time progressed, worries related to vaccine side effects, or the effectiveness of vaccines, feeling pressured to get vaccinated or restrictions imposed if not getting vaccinated emerged in the 12-month follow-up.

 Strengths and weaknesses

The major strength of this study is the large cohort and the prospective design that enabled to study the changes over time. The good response rates at follow-ups (80%) enable us to study such changes with good validity. Wherever possible, valid questionnaires were used, to avoid misclassification. Non-standardized questions and items were piloted by manual therapists prior to distribution of the baseline questionnaire, to ensure comprehensiveness. Further, the mixed method approach allowed for a detailed and deepened understanding of the study aims. Nevertheless, since it is a challenge to measure lifestyle as alcohol consumption, physical activity and sedentary time with questionnaires, we cannot rule out an underestimation of a risk behavior during the follow-up. If such misclassification differs between men and women, and between older and younger participants we might have missed a potential difference between subgroups. Further, if subgroups differed regarding any other factor related to lifestyle, we might wrongly have concluded that group differences were lacking.

Comparisons of the cohort with eligible participants was possible regarding some variables (age, sex, occupation, and place of business), and only a slight difference with regards to sex was found with a larger proportion of our sample being female (46% versus 40%). Thus, we conclude that the sample is representative.

 Conclusion

Swedish manual therapists maintained good lifestyle habits except for a small decrease in physical activity and slight increase in sedentary behavior and subjective mental health impact by the pandemic over time. There were small differences in terms of maladaptive coping, alcohol consumption, and tobacco consumption, however, these differences were not likely clinically relevant. The therapists seemed conscientious regarding health promotion measures during one year of the COVID-19 pandemic.

 Supporting information Supporting table S1-S12.

(DOCX)

The authors would like to express gratitude to Sofie Jonsson for project administration and assistance, and the participating manual therapists for their contribution.

 References WHO. Coronavirus disease (COVID-19) pandemic 2020. Accessed 2023 October 1. https://www.who.int/emergencies/diseases/novel-coronavirus-2019 Winblad U, Swenning A-K, Spangler D. Soft law and individual responsibility: a review of the Swedish policy response to COVID-19. Health Econ Policy Law. 2022;17(1):48–61. doi: 10.1017/S1744133121000256 34372959 Björkman A, Gisslén M, Gullberg M, Ludvigsson J. The Swedish COVID-19 approach: a scientific dialogue on mitigation policies. Front Public Health. 2023;11:1206732. doi: 10.3389/fpubh.2023.1206732 37546333 Ludvigsson JF. How Sweden approached the COVID-19 pandemic: summary and commentary on the National Commission Inquiry. Acta Paediatr. 2023;112(1):19–33. doi: 10.1111/apa.16535 36065136 Spetz M, Lundberg L, Nwaru C, Li H, Santosa A, Leach S, et al. The social patterning of Covid-19 vaccine uptake in older adults: a register-based cross-sectional study in Sweden. Lancet Reg Health Eur. 2022;15:100331. doi: 10.1016/j.lanepe.2022.100331 35252941 Hoy DG, Smith E, Cross M, Sanchez-Riera L, Buchbinder R, Blyth FM, et al. The global burden of musculoskeletal conditions for 2010: an overview of methods. Ann Rheum Dis. 2014;73(6):982–9. doi: 10.1136/annrheumdis-2013-204344 24550172 Oncina-Cánovas A, Compañ-Gabucio L, Vioque J, Ruiz-Canela M, Corella D, Salas-Salvadó J, et al. More adult women than men at high cardiometabolic risk reported worse lifestyles and self-reported health status in the COVID-19 lockdown. Nutrients. 2024;16(13):2000. doi: 10.3390/nu16132000 38999747 López-Morales H, Trudo RG, García MJ, Del-Valle MV, Yerro M, Poó FM, et al. Depression and anxiety in the context of the COVID-19 pandemic: a 6-waves longitudinal study in the Argentine population. Soc Psychiatry Psychiatr Epidemiol. 2025;60(3):631–44. doi: 10.1007/s00127-024-02746-7 39110224 González-Hijón J, Kähler AK, Frans EM, Valdimarsdóttir UA, Sullivan PF, Fang F, et al. Unravelling the link between sleep and mental health during the COVID-19 pandemic. Stress Health. 2023;39(4):828–40. doi: 10.1002/smi.3223 36649144 Arango-Martinez G, Sarmiento LB, Forero IC, Carreno LC, Cadena-Camargo Y. Fear of the unknown: experience of frontline healthcare workers with coping strategies used to face the COVID 19 pandemic. PLOS Glob Public Health. 2024;4(8):e0003373. doi: 10.1371/journal.pgph.0003373 39146313 Glette MK, Bates DW, Dykes PC, Wiig S, Kringeland T. A resilience perspective on healthcare personnels’ experiences of managing the COVID-19 pandemic: a qualitative study in Norwegian nursing homes and come care services. BMC Health Serv Res. 2023;23(1):1177. doi: 10.1186/s12913-023-10187-2 37898762 Howe AS, Jules K, Tan JK, Khan R, Li AK, Edwards B, et al. The effects of occupational and mental stress among home care rehabilitation professionals working during the COVID-19 pandemic: an exploratory qualitative study. Home Health Care Manag Pract. 2024;36(3):230–42. doi: 10.1177/10848223231225246 39149713 Johnson CD, Green BN, Konarski-Hart KK, Hewitt EG, Napuli JG, Foshee WK, et al. Response of practicing chiropractors during the early phase of the COVID-19 pandemic: a descriptive report. J Manipulative Physiol Ther. 2020;43(5):403.e1–403.e21. doi: 10.1016/j.jmpt.2020.05.001 32546381 Moore C, Wong AYL, de Luca K, De Carvalho D, Johansson MS, Pohlman KA, et al. The impact and public health response of chiropractors to the COVID-19 pandemic: a survey across four continents. Chiropr Man Therap. 2022;30(1):24. doi: 10.1186/s12998-022-00432-6 35534844 Neff SM, Deyo RL, Mac Auley AL, Lawrence DJ. Cross-sectional survey of opinions, professional changes, and personal hardships of COVID-19 on chiropractors in the United States. J Manipulative Physiol Ther. 2022;45(2):127–36. doi: 10.1016/j.jmpt.2022.04.002 35753881 Weiss N, Skillgate E, Axén I. Psychological distress and musculoskeletal pain in manual therapists during the second wave of the COVID-19 pandemic in Sweden: a cross-sectional study. Chiropr Man Therap. 2023;31(1):34. doi: 10.1186/s12998-023-00511-2 37700309 Lönn A, Kallings LV, Börjesson M, Ekblom Ö, Ekström M. Convergent validity of commonly used questions assessing physical activity and sedentary time in Swedish patients after myocardial infarction. BMC Sports Sci Med Rehabil. 2022;14(1):117. doi: 10.1186/s13102-022-00509-y 35751097 Socialstyrelsen. Syfte och bakgrund till frågorna i nationella folkhälsoenkäten (Hälsa på lika villkor 2022). 2022. Olsson SJG, Ekblom Ö, Andersson E, Börjesson M, Kallings LV. Categorical answer modes provide superior validity to open answers when asking for level of physical activity: a cross-sectional study. Scand J Public Health. 2016;44(1):70–6. doi: 10.1177/1403494815602830 26392418 Kallings LV, Olsson SJG, Ekblom Ö, Ekblom-Bak E, Börjesson M. The SED-GIH: a single-item question for assessment of stationary behavior-a study of concurrent and convergent validity. Int J Environ Res Public Health. 2019;16(23):4766. doi: 10.3390/ijerph16234766 31795109 Nordin M, Åkerstedt T, Nordin S. Psychometric evaluation and normative data for the Karolinska sleep questionnaire. Sleep and Biological Rhythms. 2013;11(4):216–26. doi: 10.1111/sbr.12024 Aronsson G, Astvik W, Gustafsson K. Arbetsvillkor, återhämtning och hälsa - en studie av förskola, hemtjänst och socialtjänst. Göteborgs universitet; 2010. 4. Buysse DJ. Insomnia. JAMA. 2013;309(7):706–16. doi: 10.1001/jama.2013.193 23423416 Bush K, Kivlahan DR, McDonell MB, Fihn SD, Bradley KA. The AUDIT alcohol consumption questions (AUDIT-C): an effective brief screening test for problem drinking. Ambulatory Care Quality Improvement Project (ACQUIP). Alcohol use disorders identification test. Arch Intern Med. 1998;158(16):1789–95. doi: 10.1001/archinte.158.16.1789 9738608 Muhonen T, Torkelson E. Kortversioner av frågeformulär inom arbets- och hälsopsykologi—om att mäta coping och optimism. Nordisk Psykologi. 2005;57(3):288–97. doi: 10.1080/00291463.2005.10637375 Carver CS. You want to measure coping but your protocol’s too long: consider the brief COPE. Int J Behav Med. 1997;4(1):92–100. doi: 10.1207/s15327558ijbm0401_6 16250744 Meyer B. Coping with severe mental illness: relations of the brief COPE with symptoms, functioning, and well-being. J Psychopathol Behav Assess. 2001;23(4):265–77. doi: 10.1023/a:1012731520781 Su X-Y, Lau JT, Mak WW, Choi KC, Feng T-J, Chen X, et al. A preliminary validation of the brief COPE instrument for assessing coping strategies among people living with HIV in China. Infect Dis Poverty. 2015;4:41. doi: 10.1186/s40249-015-0074-9 26370135 Ahmed O, Ahmed MZ, Alim SMAHM, Khan MDAU, Jobe MC. COVID-19 outbreak in Bangladesh and associated psychological problems: an online survey. Death Stud. 2022;46(5):1080–9. doi: 10.1080/07481187.2020.1818884 32915701 Faisal RA, Jobe MC, Ahmed O, Sharker T. Replication analysis of the COVID-19 worry scale. Death Stud. 2022;46(3):574–80. doi: 10.1080/07481187.2020.1815104 32866090 Faruk Uygur Ö, Uygur H, Demiröz D, Ahmed O. COVID-19 worry and related factors: Turkish Adaptation and psychometric properties of the COVID-19 worry scale. Alpha Psych. 2022;23(6):276–83. doi: 10.5152/alphapsychiatry.2022.22926 36628379 Halekoh U, Højsgaard S, Yan J. The R Package geepack for generalized estimating equations. J Stat Soft. 2006;15(2). doi: 10.18637/jss.v015.i02 Touloumis A. R Package multgee: a generalized estimating equations solver for multinomial responses. J Stat Soft. 2015;64(8). doi: 10.18637/jss.v064.i08 Graneheim UH, Lundman B. Qualitative content analysis in nursing research: concepts, procedures and measures to achieve trustworthiness. Nurse Educ Today. 2004;24(2):105–12. doi: 10.1016/j.nedt.2003.10.001 14769454 van der Noordt M, IJzelenberg H, Droomers M, Proper KI. Health effects of employment: a systematic review of prospective studies. Occup Environ Med. 2014;71(10):730–6. doi: 10.1136/oemed-2013-101891 24556535 Larsson K, Onell C, Edlund K, Källberg H, Holm LW, Sundberg T, et al. Lifestyle behaviors in Swedish university students before and during the first six months of the COVID-19 pandemic: a cohort study. BMC Public Health. 2022;22(1):1207. doi: 10.1186/s12889-022-13553-7 35710368 Backman B, George N, Whiteside B, McKay FH, Dunn M. Investigating the impact of COVID-19 on international student wellbeing in Australia. Health Promot J Austr. 2025;36(2):e926. doi: 10.1002/hpja.926 39318172 Sullivan SM, Sullivan JM, Orey D, Baptist NK. Racial differences in feelings of distress during the COVID-19 pandemic and John Henryism active coping in the United States: results from a national survey. Soc Sci Q. 2024;105(3):514–27. doi: 10.1111/ssqu.13354 39309452 Garfin DR, Thompson RR, Holman EA. Acute stress and subsequent health outcomes: a systematic review. J Psychosom Res. 2018;112:107–13. doi: 10.1016/j.jpsychores.2018.05.017 30097129 10.1371/journal.pone.0327600.r001 Decision Letter 0 Campus Guglielmo Academic Editor 2025 Guglielmo Campus This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version 0

10 Jan 2025

PONE-D-24-54978Health aspects and lifestyle of licensed manual therapists during the COVID-19 pandemic in Sweden; the CAMP cohort studyPLOS ONE

Dear Dr. Weiss,

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Reviewer #1: Yes

Reviewer #2: Yes

**********

2. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #2: Yes

**********

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Reviewer #1: No

Reviewer #2: No

**********

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Reviewer #2: Yes

**********

5. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: I am grateful for the opportunity to contribute to the peer review process of this manuscript, which refers to a longitudinal study in a COVID management context different from the ordinary one of alternating lockdowns.

The authors have presented very clearly the purpose of their study, the methods used and the results obtained. I would like to express my sincere appreciation to them for the work done. Below are some minor comments and some ideas for a deeper understanding of the study results.

1. In the Introduction the authors should add information about vaccination in Sweden. According to Spetz et al., in Sweden, the vaccination program started on 27th December 2020 and by 5th November 2021, 85% of the adult population had received their first dose. Therefore, the baseline data should refer almost entirely to subjects who were not yet vaccinated, while the follow-up data were collected when the vaccine was fully available and, at 12 months, after having also overcome the major uncertainties associated with vaccination. In my opinion, this aspect should also be considered in the discussion.

2. sub-section Physical activity: If I am not mistaken, according to the cited reference [18], the physical activity data should have been managed in a categorical way, on a scale ranging from 3 to 18 instead of the proposed “minutes of activity”. Instead, the authors considered the minutes, converting the categorical response into the central numerical value of the class. It is not clear to me, therefore, whether this method of converting categorical data into a continuous variable (minutes) has had any validation in the literature. As a small comment, regarding the response alternatives: “1-30 minutes”, “30-60 minutes”, “60-90 minutes”, etc., a more accurate data collection would be obtained, for example, by indicating "1-29 minutes", "30-59 minutes" and so on. The original indication "Less than 30 minutes" (as reported in [18]) would be preferable to "1-30", in my opinion.

3. At the end of the Tobacco and alcohol use section there is a typo on AUDIT-C.

4. Regarding the free text variables, how was the question formulated at 12 months? Such as baseline (What have you done to promote your own health during the COVID-19 pandemic?) or, for example, "What have you done to promote your own health during the last 12 months?".

5. Please add appropriate citations for R packages gee and multgee.

6. sub-section Longitudinal lifestyle patterns: I believe that indicating the sedentary time variation even in minutes can help the reader.

7. Table 2: Why was the 34-year threshold taken into consideration? I suggest adding a reason. Furthermore, to assist readers who are not experts in GEE methods, I suggest clarifying what is reported in the line "Mean difference in change baseline to 12 months (95% CI)". The same goes for other similar tables.

8. Table 5: To highlight the appearance of the new category "Change profession", I suggest introducing a decimal instead of reporting 0%. Personally, I was very intrigued by the classification of "Change profession" among the activities for the promotion of mental health. Did the respondents themselves give this indication? Since it seems to be a relevant result, perhaps the authors can spend a few more words on it.

9. Table 6 and related text (lines 233-237): If I understand correctly, all 202 individuals who responded to the baseline indicated at least one negative impact, but 70 of them also indicated positive impacts. Is that right?

10. Tables 5-10 overall: I would like to suggest reviewing the indication of percentages. With reference to table 10, it is really confusing to find indications higher than 100%. Perhaps, these particular cases could be better explained in the legend. Or, the analysis procedure of the individual responses could be illustrated in greater detail in the methods, perhaps with an example (even a fictitious one). Finally, why COVID-19-related worries were not asked at the baseline as well?

References

Spetz, M., Lundberg, L., Nwaru, C., Li, H., Santosa, A., Leach, S., ... & Nyberg, F. (2022). The social patterning of Covid-19 vaccine uptake in older adults: A register-based cross-sectional study in Sweden. The Lancet Regional Health–Europe, 15.

Reviewer #2: Introduction

Lines 58 to 62: The authors discuss how the pandemic impacted the lifestyle and mental health of adolescents worldwide. I suggest revising this section by incorporating references from the scientific literature that highlight the pandemic's impact across all life stages: youth, adults, and the elderly. Alternatively, consider including a reference that focuses on the pandemic's impact on the mental health and lifestyle of healthcare professionals.

Methods

Participants: While the methodological details have already been published and do not need to be repeated in the current manuscript, it would be valuable for readers to know the inclusion and exclusion criteria for participants, such as sex, age group, pre-existing clinical conditions, exclusion of participants with prior illnesses that could interfere with the outcomes, as well as the total number of participants recruited or other criteria applied in the study.

Other Considerations

Based on the manuscript itself (and not the reference to the larger study), the study does not appear to align with the characteristics of a classical cohort study in epidemiology. The authors did not explicitly describe (at least in the text) how participants were selected for exposure versus non-exposure to the factor of interest (lifestyle). I suggest that the authors include these details in the manuscript. Additionally, if the study is methodologically a prospective web survey, I strongly recommend replacing the term "cohort study" with "repeated web surveys in the same population" to more accurately reflect the aim of evaluating lifestyle changes. Furthermore, I suggest specifying that this is a mixed-methods (qualitative-quantitative) study.

Follow-up: Please clarify in the methodology how the authors handled loss to follow-up and whether this loss was selective.

**********

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Reviewer #1: Yes:  Antonella Bodini

Reviewer #2: No

**********

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Submitted filename: PONE-D-24-54978-review.pdf

 10.1371/journal.pone.0327600.r002 Author response to Decision Letter 1 Submission Version 1

6 Mar 2025

Reviewer #1: I am grateful for the opportunity to contribute to the peer review process of this manuscript, which refers to a longitudinal study in a COVID management context different from the ordinary one of alternating lockdowns.

The authors have presented very clearly the purpose of their study, the methods used and the results obtained. I would like to express my sincere appreciation to them for the work done. Below are some minor comments and some ideas for a deeper understanding of the study results.

Response: Thank you for your valuable comments which we believe have improved the quality and readability of the manuscript.

1. In the Introduction the authors should add information about vaccination in Sweden. According to Spetz et al., in Sweden, the vaccination program started on 27th December 2020 and by 5th November 2021, 85% of the adult population had received their first dose. Therefore, the baseline data should refer almost entirely to subjects who were not yet vaccinated, while the follow-up data were collected when the vaccine was fully available and, at 12 months, after having also overcome the major uncertainties associated with vaccination. In my opinion, this aspect should also be considered in the discussion.

Response: Thank you for the valuable suggestion. We have added information regarding the Swedish vaccine program in the introduction, se lines 51-56:

“Sweden’s vaccination program against COVID-19 were initiated in the end of 2020 and was implemented in stages depending on risk status. Elderly people and frontline healthcare workers were among the first groups that received the vaccine, and thereafter it was progressively made available for other groups in the population based on age and pre-existing conditions. By November 2021, 85% of the adult population in Sweden had received their first dose [5].”

Since worry was not measured at baseline, we cannot relate that to the vaccination status in the discussion. Nevertheless, we have also raised opinions related to vaccination from the free-text answers in the discussion, see lines 342-346:

“Several subcategories related to the COVID-19 vaccination emerged from the free-text questions. In the 6-month follow-up, a few of the therapists raised worries concerning being last of the healthcare workers being vaccinated. As time progressed, worries related to vaccine side effects, or the effectiveness of vaccines, feeling pressured to get vaccinated or restrictions imposed if not getting vaccinated emerged in the 12-month follow-up. “

2. sub-section Physical activity: If I am not mistaken, according to the cited reference [18], the physical activity data should have been managed in a categorical way, on a scale ranging from 3 to 18 instead of the proposed “minutes of activity”. Instead, the authors considered the minutes, converting the categorical response into the central numerical value of the class. It is not clear to me, therefore, whether this method of converting categorical data into a continuous variable (minutes) has had any validation in the literature. As a small comment, regarding the response alternatives: “1-30 minutes”, “30-60 minutes”, “60-90 minutes”, etc., a more accurate data collection would be obtained, for example, by indicating "1-29 minutes", "30-59 minutes" and so on. The original indication "Less than 30 minutes" (as reported in [18]) would be preferable to "1-30", in my opinion.

Response: Thank you for raising this comment. We managed the physical activity as proposed, however, instead of forming an index with the total points ranging from 3-18 we replaced each score with the central value of minutes for each category. E.g., 30-60 minutes of physical exercise would equate to 90 minutes in total physical activity (45 minutes * 2), instead of 4 points in the PA-index. This was done to make it easier for the reader to interpret the results.

Further, we agree that the questions would be more accurate as proposed, with categories “1-29 minutes” or less than 30 minutes as originally constructed. However, we do not believe this modification of the response alternatives resulted in a large misclassification of the measure.

3. At the end of the Tobacco and alcohol use section there is a typo on AUDIT-C.

Response: Thank you for noticing this typo. It has been corrected.

4. Regarding the free text variables, how was the question formulated at 12 months? Such as baseline (What have you done to promote your own health during the COVID-19 pandemic?) or, for example, "What have you done to promote your own health during the last 12 months?".

Response: Thank you for the question. We have added a detailed description of each free-text question.

See line 159-163: “Further, a free-text question was also added, asking participants to list the three largest worries related to their clinical practice and the COVID-19 pandemic with six months recall time: “List the three main worries related to your clinical practice and the COVID-19 pandemic”. In the beginning of the section regarding COVID-19-related worries, it was specified that the question related to the last six months.”

And line 172-183: “Additionally, those answering “Yes” in either positive or negative direction to the questions described above had the possibility to deepen their answer in free text. At baseline, the questions were: “Comments regarding how the COVID-19 impacted your physical health”, “Comments regarding how the COVID-19 impacted your mental health”, “Comments regarding how your impacted physical health due to the COVID-19 pandemic affected your work ability”, and “Comments regarding how your impacted mental health due to the COVID-19 pandemic affected your work ability”. At the 12-month follow-up, the questions were: “Comments regarding how the COVID-19 impacted your physical health the last six months”, “Comments regarding how the COVID-19 impacted your mental health the last six months”, “Comments regarding how your impacted physical health due to the COVID-19 pandemic affected your work ability the last six months”, and “Comments regarding how your impacted mental health due to the COVID-19 pandemic affected your work ability the last six months”.”

And line 185-190: “Participants had the opportunity to express their experiences freely in several free text questions and statements concerning their health, lifestyle and the COVID-19 pandemic. Apart from those regarding COVID-19-related worries and subjective health impact by the COVID-19 pandemic described above, participants were asked the following question at baseline: “What have you done to promote your own health during the COVID-19 pandemic?”, and “What have you done to promote your own health the past six months?” at the 12-month follow-up.”

5. Please add appropriate citations for R packages gee and multgee.

Response: We have added citations to the R packages. Please see lines 202-203

6. sub-section Longitudinal lifestyle patterns: I believe that indicating the sedentary time variation even in minutes can help the reader.

Response: Thank you for the comment. Considering the sedentary time was measured in hours we believe it is more appropriate to present it as such, even though it’s not consistent with the reporting metric of physical activity.

7. Table 2: Why was the 34-year threshold taken into consideration? I suggest adding a reason. Furthermore, to assist readers who are not experts in GEE methods, I suggest clarifying what is reported in the line "Mean difference in change baseline to 12 months (95% CI)". The same goes for other similar tables.

Response: Thank you for the comment. The 34-year cut-off is simply the median age of the sample. This is also described in the statistical analysis, see lines 197-201:

“Separate models were conducted for each variable over the follow-up period, and stratified analyses were conducted based on sex (male/female), median age (≤ 34 years/>34 years), and business constellation (working alone/with few or with many colleagues) with the addition of an interaction term between group and time to study the change in the trajectory slope over time between the groups.”

We have revised the “Mean difference in change baseline to 12 months (95% CI)", for clarity, please see revised tables 2-4.

8. Table 5: To highlight the appearance of the new category "Change profession", I suggest introducing a decimal instead of reporting 0%. Personally, I was very intrigued by the classification of "Change profession" among the activities for the promotion of mental health. Did the respondents themselves give this indication? Since it seems to be a relevant result, perhaps the authors can spend a few more words on it.

Response: We have added a decimal to the tables 5-10. We agree that this category was interesting. We used a manifest content analysis which were very “word centered”, thus, the participants’ answers clearly stated that they changed profession to promote their mental health. Considering only 2 participants mentioned this, we believe the category is too small to elaborate on and give room in the manuscript text.

9. Table 6 and related text (lines 233-237): If I understand correctly, all 202 individuals who responded to the baseline indicated at least one negative impact, but 70 of them also indicated positive impacts. Is that right?

Response: Thank you for the comment. We realize the presentation of the results was not clear. We have revised all tables presenting the qualitative analyses (Table 5-10).

As noted in the footnotes of the tables, each participant’s response could generate several codes and contribute to multiple subcategories forming the categories. Thus, this implies that the total number of counted codes are higher than the total number of participant responses. In the revised tables, the percentage for each category is calculated based on the total number of counted codes instead of number of individual responses (as earlier), we believe this makes it clearer for the reader to interpret the tables.

10. Tables 5-10 overall: I would like to suggest reviewing the indication of percentages. With reference to table 10, it is really confusing to find indications higher than 100%. Perhaps, these particular cases could be better explained in the legend. Or, the analysis procedure of the individual responses could be illustrated in greater detail in the methods, perhaps with an example (even a fictitious one).

Response: Thank you for the comment. Please see our previous response regarding this. We hope the revised tables make it clearer.

Finally, why COVID-19-related worries were not asked at the baseline as well?

Response: We did not consider studying COVID-19-related worries specifically when designing the study. However, as the pandemic progressed, and this was flagged as a concern in other studies, we added the CWS with a 6-month recall at both the 6- and 12-month follow-up.

References

Spetz, M., Lundberg, L., Nwaru, C., Li, H., Santosa, A., Leach, S., ... & Nyberg, F. (2022). The social patterning of Covid-19 vaccine uptake in older adults: A register-based cross-sectional study in Sweden. The Lancet Regional Health–Europe, 15.

Reviewer #2:

Introduction

Lines 58 to 62: The authors discuss how the pandemic impacted the lifestyle and mental health of adolescents worldwide. I suggest revising this section by incorporating references from the scientific literature that highlight the pandemic's impact across all life stages: youth, adults, and the elderly. Alternatively, consider including a reference that focuses on the pandemic's impact on the mental health and lifestyle of healthcare professionals.

Response: Thank you for the valuable comment. Reference number 8 (Lopez-Morales et al. 2024) is based on all age groups. We have revised to change the comparison population in Sweden, see lines 65-67:

“Financial instability, fear of infection and the unpredictable situation led to poor mental health in some countries [8], while in Sweden, measures of mental health remained stable over time in a general population sample of adults [9].”

Methods

Participants: While the methodological details have already been published and do not need to be repeated in the current manuscript, it would be valuable for readers to know the inclusion and exclusion criteria for participants, such as sex, age group, pre-existing clinical conditions, exclusion of participants with prior illnesses that could interfere with the outcomes, as well as the total number of participants recruited or other criteria applied in the study.

Response: Thank you for the comment. The inclusion criteria were clinically active chiropractor or naprapath in Sweden, or undergoing licensing practice, which is described on line 87-89:

“Clinically active chiropractors and naprapaths, licensed by the National Board of Health and Welfare in Sweden, and those undergoing licensing practice were invited to participate, and 816 manual therapists were included.”

We did not exclude participants based on any characteristic or demographics mentioned, or based on pre-existing health conditions, however, these were measured and controlled for in analyses.

Other Considerations

Based on the manuscript itself (and not the reference to the larger study), the study does not appear to align with the characteristics of a classical cohort study in epidemiology. The authors did not explicitly describe (at least in the text) how participants were selected for exposure versus non-exposure to the factor of interest (lifestyle). I suggest that the authors include these details in the manuscript. Additionally, if the study is methodologically a prospective web survey, I strongly recommend replacing the term "cohort study" with "repeated web surveys in the same population" to more accurately reflect the aim of evaluating lifestyle changes. Furthermore, I suggest specifying that this is a mixed-methods (qualitative-quantitative) study.

Response: Thank you for the comment. The analyses do not compare exposure status and a specific outcome of interest, rather the change of exposure status over time in generalized estimating equations (GEE). For dichotomized exposures such as impaired sleep and tobacco consumption, there is a clearly described cut-off for classification. For the other exposures, a continuous scale was used, and we assessed the change in score between baseline and the 12—month follow-up. How the variables were collected and categorized are described under “variables” in the methods section, and how they were handled in the analyses under “statistical analysis”.

Furthermore, we agree that it should be clearly stated that the methods of the study were mixed methods. We have revised and incorporated this into the manuscript. See lines 81-83:

“This study was of mixed methods design and was based on the Corona And Manual Professions (CAMP) study, ClinicalTrials register identifier: NCT04834583. The study was approved by the Swedish Ethical Review Authority (Dnr 2020-03836).”

We do however respectfully disagree regarding the classification of the study the article is based on not being a cohort study due to the use of repeated web surveys. The CAMP cohort study is a classical cohort study in our opinion.

Follow-up: Please clarify in the methodology how the authors handled loss to follow-up and whether this loss was selective.

Response: Please see the revised figure 1 for clarity regarding study flow and attrition. Missing data was not handled specifically in the analyses. Luckily, we had a high response rate in the follow-up surveys, and thus did not examine this further. The potential impact of missing on the results of the study are hence minor.

Submitted filename: Response to reviewers.docx

 10.1371/journal.pone.0327600.r003 Decision Letter 1 Kelly Laura Staff Editor 2025 Laura Kelly This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Submission Version 1

18 Jul 2025

Health aspects and lifestyle of licensed manual therapists during the COVID-19 pandemic in Sweden; the CAMP cohort study

PONE-D-24-54978R1

Dear Dr. Weiss,

We’re pleased to inform you that your manuscript has been judged scientifically suitable for publication and will be formally accepted for publication once it meets all outstanding technical requirements.

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Division Editor

PLOS One

Additional Editor Comments (optional):

Reviewers' comments:

Reviewer's Responses to Questions

Comments to the Author

1. If the authors have adequately addressed your comments raised in a previous round of review and you feel that this manuscript is now acceptable for publication, you may indicate that here to bypass the “Comments to the Author” section, enter your conflict of interest statement in the “Confidential to Editor” section, and submit your "Accept" recommendation.

Reviewer #1: All comments have been addressed

Reviewer #3: All comments have been addressed

**********

2. Is the manuscript technically sound, and do the data support the conclusions?

The manuscript must describe a technically sound piece of scientific research with data that supports the conclusions. Experiments must have been conducted rigorously, with appropriate controls, replication, and sample sizes. The conclusions must be drawn appropriately based on the data presented.

Reviewer #1: Yes

Reviewer #3: Yes

**********

3. Has the statistical analysis been performed appropriately and rigorously?

Reviewer #1: Yes

Reviewer #3: Yes

**********

4. Have the authors made all data underlying the findings in their manuscript fully available?

The PLOS Data policy requires authors to make all data underlying the findings described in their manuscript fully available without restriction, with rare exception (please refer to the Data Availability Statement in the manuscript PDF file). The data should be provided as part of the manuscript or its supporting information, or deposited to a public repository. For example, in addition to summary statistics, the data points behind means, medians and variance measures should be available. If there are restrictions on publicly sharing data—e.g. participant privacy or use of data from a third party—those must be specified.

Reviewer #1: Yes

Reviewer #3: Yes

**********

5. Is the manuscript presented in an intelligible fashion and written in standard English?

PLOS ONE does not copyedit accepted manuscripts, so the language in submitted articles must be clear, correct, and unambiguous. Any typographical or grammatical errors should be corrected at revision, so please note any specific errors here.

Reviewer #1: Yes

Reviewer #3: Yes

**********

6. Review Comments to the Author

Please use the space provided to explain your answers to the questions above. You may also include additional comments for the author, including concerns about dual publication, research ethics, or publication ethics. (Please upload your review as an attachment if it exceeds 20,000 characters)

Reviewer #1: (No Response)

Reviewer #3: Further minor comments on the revision,

Line 94 - enter the year after Jan1st assume is 2021

**********

7. PLOS authors have the option to publish the peer review history of their article (what does this mean? ). If published, this will include your full peer review and any attached files.

If you choose “no”, your identity will remain anonymous but your review may still be made public.

Do you want your identity to be public for this peer review? For information about this choice, including consent withdrawal, please see our Privacy Policy .

Reviewer #1: Yes:  Antonella Bodini

Reviewer #3: No

**********

 10.1371/journal.pone.0327600.r004 Acceptance letter Kelly Laura Staff Editor 2025 Laura Kelly This is an open access article distributed under the terms of the Creative Commons Attribution License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

PONE-D-24-54978R1

PLOS ONE

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