Physical activities mediate the correlations between serum creatinine and bone mineral density in Chinese

Background The relationship between serum creatinine (CR) and osteoporosis under normal renal function and the possible mediating effects mediated by physical activity (PA) are largely unknown. Methods A total of 4,137 elderly Chinese subjects were recruited. Three models including different covariates were established. Correlation analysis and multiple linear regression analysis were used to evaluate the relationship between CR and bone mineral density (BMD) and also under different PA pattern. Logistic regression was used to investigate the interaction between CR*PA with osteoporosis. PA was used as a moderating variable to investigate the relationship between CR and BMD. Results As we expected, the association between CR and BMD remained significant after adjusting covariates in all models. The relationship between CR and BMD showed changeable pattern in case of different physical activity. Specially, the moderating effects of PA on serum creatinine and BMD were significant for all models only in the case of medium physical activity (PA3). Conclusions In Chinese elderly under normal renal function, serum CR is positively correlated with BMD, and medium physical activity has mediation effect on such correlation.