Physical Activity and the Association Between Musculoskeletal Complaints and Sleep Quality in Adults and Older Adults From Primary Care: A Cross‐Sectional Study

BACKGROUND: Musculoskeletal complaints are the leading cause of disability worldwide and are often associated with poor sleep quality. While evidence suggests that physical activity (PA) positively influences both pain management and sleep quality, it remains unclear whether PA influences the association between musculoskeletal complaints and sleep. This study aimed to investigate the association between musculoskeletal complaints and poor sleep quality, and whether PA modifies this association in adults from primary care. METHODS: This cross-sectional study analysed data from a Brazilian cohort. Musculoskeletal complaints were defined by self-reported diagnosis of osteoarthritis or low back pain. Sleep quality was assessed using the Mini-Sleep Questionnaire. PA was measured using the Baecke questionnaire. Binary logistic regression was used to test the association between musculoskeletal complaints and poor sleep quality. RESULTS: A total of 557 patients were included (mean age 70.0 ± 8.4 years). Musculoskeletal complaints were associated with poor sleep quality even after adjusting for confounders (OR: 2.36 [95% CI: 1.56 to 3.57]). Stratified analyses showed that this association remained statistically significant among physically inactive participants (OR: 2.47 [95% CI: 1.51 to 4.05]), while the estimate among physically active participants was imprecise and included the null value (OR: 2.10 [95% CI: 0.95 to 4.62]). No statistically significant interaction between musculoskeletal complaints and PA was observed (p-value for interaction = 0.552). CONCLUSIONS: Musculoskeletal complaints are associated with poor sleep quality. Although stratified analyses suggested different effect estimates according to PA, the formal interaction analysis did not support effect modification by PA. These findings should therefore be interpreted cautiously.