People in primary care who reported musculoskeletal complaints were more likely to report poor sleep than those without such complaints. Poor sleep was reported by 277 people with complaints, or 68.9%, compared with 71 people without complaints, or 45.8%. After adjustment, the association remained: the odds ratio was 2.36, with a 95% confidence interval from 1.56 to 3.57. An odds ratio compares the odds of an outcome between two groups, while the confidence interval shows the uncertainty around the estimate. Because the study was cross-sectional, the finding does not show that musculoskeletal complaints caused poor sleep.
What the researchers measured
Musculoskeletal complaints were identified from self-reported physician diagnoses of osteoarthritis or low back pain, with the study definition referring to osteoarthritis pain or low back pain. Sleep quality was measured with the Mini-Sleep Questionnaire. It contains 10 questions scored from 1 to 7, producing a total score from 10 to 70. A score of at least 25 was classified as poor sleep quality.
The researchers used crude and multivariable binary logistic regression to estimate the association. They reported a crude odds ratio of 2.62, with a 95% confidence interval from 1.79 to 3.83, and an adjusted odds ratio of 2.36. The analysis also included an interaction term between musculoskeletal complaints and physical activity, along with exploratory analyses that separated participants by activity status. Statistical significance was set at p < 0.05.
A predominantly older primary-care sample
This was a cross-sectional secondary analysis of the 2016 assessment wave of a cohort that began in 2010. Participants had been recruited through Brazilian National Health System primary-care units in Bauru, São Paulo. The analysis included 557 people, representing 57.4% of the initial cohort.
The participants had a mean age of 70.0 years, with a standard deviation of 8.40 years. The group included 147 men and 410 women, and 381 people, or 68.4%, were at least 65. Musculoskeletal complaints were reported by 72.2% of the sample, while 26.9% were classified as physically active.
The report listed several reasons why members of the original cohort were not included in the analysis: 238 people, or 24.5%, had incorrect phone numbers or did not answer calls; 66, or 6.8%, refused to continue; 20, or 2.1%, could not attend the healthcare unit; and 89, or 9.2%, had died.
Physical activity did not clearly change the link
Physical activity was measured with the 16-question Baecke questionnaire. Participants whose total score was at or above the sample's 75th percentile, representing the top 25%, were classified as physically active. This sample-based definition identified 26.9% of participants as active.
The formal test of whether physical activity changed the association produced an interaction-term odds ratio of 1.30, with a 95% confidence interval from 0.55 to 3.05. The interval includes the no-difference value, and the authors reported no evidence that physical activity modified the association between musculoskeletal complaints and poor sleep.
An exploratory analysis found an association among physically inactive participants, with an odds ratio of 2.47 and a 95% confidence interval from 1.51 to 4.05. Among active participants, the estimate was 2.10, with a confidence interval from 0.95 to 4.62, so it was not statistically significant. The authors cautioned that these subgroup results should not be treated as evidence of effect modification because the formal interaction test was not statistically significant.
Why the result needs caution
The study design cannot establish whether musculoskeletal complaints came before poor sleep, whether poor sleep preceded the complaints, or whether another factor contributed to both. The cross-sectional design prevents causal inference. In addition, the measures relied on self-report, which can introduce measurement error and recall bias.
The findings also come from a predominantly older sample recruited through primary care in one Brazilian city. They therefore do not directly establish whether the same association would appear in younger populations or in people outside primary-care settings. The results likewise do not show that increasing physical activity would improve sleep or change the relationship.
Funding and disclosures
JPK and IRL received scholarship support from FAPESP grants and CAPES finance code 001. CAPES funded the article processing charge. The authors declared no conflicts of interest, and the study data are available from the corresponding author upon reasonable request.
Paper data and sources
Original title: Physical Activity and the Association Between Musculoskeletal Complaints and Sleep Quality in Adults and Older Adults From Primary Care: A Cross‐Sectional Study
Authors: Kappaum J, Pinto R, Freire A et al.
Journal/Repository: Musculoskeletal care
Status: Peer-reviewed
First online: 2026-10-12
DOI: Not available
Original paper · Full text