Association between physical activity and multimorbidity: a population-based cohort study.

BACKGROUND

Physical activity has been widely recognized for its important role in preventing cardiovascular and other chronic diseases. While population studies worldwide have established clear associations between physical activity and multimorbidity, these relationships in the Chinese population remain underexplored.

METHODS

This study utilized the China Health and Retirement Longitudinal Study (CHARLS) database to classify physical activity levels based on metabolic equivalents (MET). Physical activity was measured using self-reported questionnaires based on the International Physical Activity Questionnaire (IPAQ). The analysis focused on the relationship between low, moderate, and high physical activity levels and various chronic diseases, as well as the co-occurrence of multiple diseases. Multivariable logistic regression models were employed to assess the association between different activity levels and the risk of chronic diseases, while stratified analyses explored the impact of demographic factors on these associations. Additionally, a restricted cubic spline (RCS) model was applied to investigate potential nonlinear relationships between total MET and chronic disease risks.

RESULTS

The final cohort included 6,244 participants with a total of 19,498 observations across five waves (2011-2020). The results showed that compared to low activity levels, moderate and high levels of physical activity reduced the risk of cardiovascular diseases and respiratory diseases, with a nonlinear dose-response relationship. High levels of physical activity also significantly lowered the risk of multimorbidity, particularly the coexistence of five or more chronic diseases (OR = 0.58, 95% CI: 0.46, 0.74, P < 0.01). However, high levels of activity were linked to higher risks of arthritis and kidney diseases. Stratified analyses revealed that demographic factors influenced the association between physical activity and disease risk.

CONCLUSION

Moderate and high levels of physical activity provide significant protection against cardiovascular and respiratory diseases and effectively reduce the risk of multimorbidity. However, the increased risk of certain metabolic and joint diseases with higher activity levels warrants further attention. Future research should clarify the impact of physical activity on different populations and chronic diseases, with randomized controlled trials needed to verify causality.