Abstract
BACKGROUND: Musculoskeletal disease (MSD) is a major cause of disability among older adults, and understanding the role of physical activity (PA) in preventing these conditions is crucial. This study aimed to explore the association between PA levels and MSD risk among adults aged 45 and above, clarify the dose‒response relationship, and provide tailored guidelines. METHODS: Using data from the China Health and Retirement Longitudinal Study (CHARLS), a cross-sectional analysis was conducted on 15,909 adults aged 45 and over. The study population was divided into MSD (n = 7014) and nMSD (n = 8895) groups based on musculoskeletal health status. PA levels were assessed using the International Physical Activity Questionnaire and categorized into low intensity physical activity (LIPA), moderate vigorous physical activity (MVPA), and vigorous physical activity (VPA). Multivariable logistic regression models and restricted cubic spline regression were used to examine the relationship between PA levels and MSD risk in middle-aged and older adults. Sensitivity analyses and stratified analyses were also performed. RESULTS: The main outcome measures were musculoskeletal diseases prevalence and PA levels. MVPA and VPA reduced MSD risk by 19% [OR = 0.81, 95% CI (0.72, 0.90), P < 0.001] and 12% [OR = 0.88, 95% CI (0.79, 0.98), P < 0.05], respectively. What's more, after adjusting for confounding factors, VPA increased risk by 32% [OR = 1.32, 95% CI (1.04, 1.66), P < 0.05]. The relationship was nonlinear, showing a U-shaped pattern with age and hypertension status as significant moderators. The optimal PA energy expenditure was identified as approximately 1500 metabolic equivalents of tasks (METs) per week for adults aged 45-74, 1400 METs per week for those aged 75 and above, and 1600 METs per week for hypertensive adults aged 45 and older. CONCLUSIONS: For adults aged 45 years and older, VPA significantly increases the risk of MSD. Adults aged 45 years and older should adjust their weekly METs based on their age. Additionally, those with hypertension should moderately increase their weekly METs to promote optimal musculoskeletal health.