¹Federal Institute for Occupational Safety and Health (BAuA), Berlin, Germany
²Institute and Polyclinic for Occupational and Social Medicine (IPAS), TU Dresden, Dresden, Germany

Text

Introduction: Sedentary behavior and long sitting times can negatively impact health. This impact can possibly include an increase in musculoskeletal complaints (MSCs). This study aimed to examine the relationship between the amount of self-reported time spent sitting at work and the one-year prevalence of MSCs upper body among workers in the Study on Mental Health at Work (S-MGA). Additionally, we aimed to examine whether leisure time physical activity and gender are effect modifiers of this relationship.

Methods: Data from the S-MGA, a five-year prospective study conducted in Germany served were analyzed. The S-MGA is a nationwide representative employee cohort. Baseline data was collected in 2012 and a follow-up survey conducted in 2017. The proportion of self-reported time spent sitting at work was measured through a single question administered at both baseline and follow-up. A version of the Nordic Musculoskeletal Questionnaire was included in the 2017 follow-up to assess the one-year prevalence of MSCs. No information on MSCs were collected at baseline.

To estimate the associations between sitting time at work at baseline and the prevalence of MSCs in the neck, shoulder, upper back, and lower back at follow-up, Poisson regression models were used. These models included both unadjusted and adjusted versions, controlling for age, gender, body mass index, occupational skill level, heavy lifting at work, psychological conditions, smoking status, leisure time physical activity, and preexisting musculoskeletal conditions. The models were also stratified by gender and leisure time physical activity levels to assess whether these factors modified the relationship between sitting at work and MSCs.

Results: The analysis included 2,082 participants, with 49.8% male and 50.2% female. Over 60% of the participants reported sitting for more than half of their workday. Baseline data on sitting at work was not consistently linked to the 12-month prevalence of MSCs in the upper body at follow-up. No significant association was found between prolonged sitting and lower back complaints. However, the relationship between occupational sitting and MSCs depended on the intensity of leisure time physical activity. The prevalence ratios (PRs) indicated a higher prevalence of MSCs in the neck (PR = 1.46; 95% CI = 1.18–1.80) and shoulder (PR = 1.30; 95% CI = 1.03–1.64) among workers who spent 25 to < 35 weekly working hours sitting and did not engage in leisure time physical activity.

Discussion: This suggests that leisure time physical activity may modify the relationship between sitting at work and musculoskeletal pain.

Conclusion: While the association between occupational sitting and MSCs warrants further investigation, the results indicate that engaging in leisure time physical activity may help mitigate the negative effects of sitting at work.