Physical activity is associated with renal function in middle-aged and elderly people in China: first cross-sectional and longitudinal evidence from the CHARLS

Objective: Chronic kidney disease (CKD) has become a common health problem among middle-aged and elderly people in China. The aim of this study was to investigate the effects of physical activity on renal function in Chinese middle-aged and elderly people. Methods: A total of 3599 participants in the 2011 China Health and Aging Longitudinal Study (CHARLS) were included in this cross-sectional study, with an eGFR <60 ml/min/1.73 m ² as the endpoint. A total of 2309 participants in the 2015 CHARLS were included in the longitudinal study, with an eGFR <60 ml/min/1.73 m ² or a ≥25% decrease in eGFR as the endpoint. Physical activity intensity was assessed by self-reports. Associations between physical activity levels and renal function were analyzed using logistic regression. Results: In cross-sectional studies, moderate physical activity (MPA) and vigorous physical activity (VPA) >300 min/week were associated with a reduced risk of renal endpoint events compared with relatively physically inactive participants (OR=0.39, 95% CI: 0.30-0.51). After correction for clinical characteristics and blood test results, VPA and MPA >300 min/week remained independent protective factors for renal function. In the longitudinal cohort, VPA and MPA >300 min/week reduced the risk of renal endpoint events by 45% (OR=0.55, 95% CI=0.38-0.80). After correcting for clinical characteristics and blood test results, VPA and MPA >300 min/week still reduced the risk of renal endpoint events by 37% (OR=0.63, 95% CI=0.43-0.92) and 39% (OR=0.61, 95%), respectively. Conclusions: Physical activity is beneficial for reducing and delaying the onset of renal insufficiency. The results of this study provide additional evidence for the renoprotective effects of exercise in non-CKD populations.