Association between relative muscle strength and cardiometabolic multimorbidity in middle-aged and older Chinese...

Relative muscle strength (RMS) serves as a valuable indicator of skeletal muscle function. As the body ages, skeletal muscle function declines gradually, leading to a range of adverse effects. Cardiometabolic multimorbidity (CMM) is a prevalent co-morbidity in middle-aged and elderly populations. However, there are few studies to investigate the association between RMS and CMM.

This study adopted a cross-sectional design, including participants from the China Health and Retirement Longitudinal Study (CHARLS) of 2011. Appendicular skeletal muscle mass (ASM) was estimated using previously validated anthropometric equations. RMS was defined as the ratio of maximum hand grip strength (HGS) to ASM. CMM was characterized by the presence of at least two cardiometabolic disorders (cardiopathy, stroke, and diabetes), as assessed through self-reported physician diagnoses. The relationship between RMS and CMM was evaluated through multifactor logistic regression analysis.

A total of 9,200 participants with a mean age of 59.49 years were included in this study. Among them, 6,844 (74.4%) had no cardiometabolic disease (CMD), 2,052 (22.3%) had a single CMD, and 304 (3.3%) had cardiometabolic multimorbidity (CMM). Multifactor logistic regression was used to evaluate the relationship between them. In the initial model, there was a negative correlation between RMS and CMM. After adjusting for confounders, this association remained statistically significant. Specifically, for each additional unit increase in RMS, the risk of CMM was reduced by 40% (OR: 0.60, 95%CI: (0.45, 0.78)). Additionally, the highest RMS value group had a lower risk of CMM compared to the lowest value group (OR: 0.46, 95%CI: (0.31, 0.67)). As indicated by the restricted cubic spline plots, there was an L-shape correlation between RMS and CMM (P for nonlinear = 0.003).

The RMS, calculated based on HGS and ASM, was a potential indicator of CMM in middle-aged and elderly adults in China.