Does knee pain mediate the association between regular physical exercise and functional independence in older adults with knee osteoarthritis?

Introduction: knee osteoarthritis was frequently associated with pain and limitations in daily functioning among older adults. Regular physical exercise was associated with lower pain and better function, but the role of pain in this relationship remained uncertain. Objective: the study examined whether knee pain statistically mediated the association between regular physical exercise and functional independence in older adults with knee osteoarthritis after adjustment for age and body mass index. Methodology: a cross-sectional observational study included 193 older adults with radiographically confirmed knee osteoarthritis. Regular exercise participation was exposure, knee pain intensity was the potential mediator, and functional independence measured with the lawton instrumental activities of daily living scale was the outcome. age and body mass index were covariates. Regression-based mediation analysis used heteroskedasticity-consistent standard errors and 10,000 bootstrap resamples. Results: regular exercise was associated with lower knee pain and higher lawton scores. greater pain showed an inverse but non-significant adjusted association with functional independence. the direct association between exercise and functional independence remained significant after accounting for pain. The estimated indirect effect through pain was positive, but its 95% bootstrap confidence interval included zero. Discussion: the findings agreed with previous research reporting favorable associations of exercise with pain and function, but lower current pain did not clearly account for the exercise–functional independence relationship. Other pathways may therefore have contributed. Conclusions: regular physical exercise is associated with lower knee pain and greater functional independence, but the hypothesized indirect pathway through pain is not statistically supported.