Association between skeletal muscle index and kidney stones in health screening populations: a single-center...

Kidney stones (KS) are highly prevalent among Chinese populations, and the skeletal muscle index (SMI)-a key marker of body composition and nutritional status-has been linked to chronic diseases, though its association with KS poorly understood. This study aimed to investigate the correlation between SMI and KS in a health screening populations, thereby providing evidence for the early identification of KS risk and the implementation of targeted health management strategies.

A total of 18,918 participants from the Health Promotion Center were enrolled in this retrospective cross-sectional study. KS were diagnosed via renal ultrasound. SMI was calculated using bioelectrical impedance analysis (BIA) with the formula: SMI = skeletal muscle mass (kg)/height (m²). Logistic regression analyses were employed to explore the relationship between SMI and KS risk, and subgroup analyses were conducted to verify the stability of this association across different demographic and clinical subgroups.

Among all participants, 813 individuals (4.3%) were diagnosed with KS. After comprehensive adjustment for multiple confounding factors in the multivariable logistic regression model, SMI was found to be positively correlated with KS risk [odds ratio (OR) =1.102; 95% confidence interval (CI): 1.000-1.213]. Compared with participants in the lowest SMI quartile (Q1), those in the highest SMI quartile (Q4) had a significantly elevated prevalence of KS (OR =1.708; 95% CI: 1.184-2.469). Subgroup analysis results indicated that the positive association between SMI and KS remained stable and consistent across multiple subgroups, with the exception of participants with diabetes.

In a single-center tertiary hospital health screening cohort in China, a higher SMI may serve as a potential risk factor for KS, offering a novel direction for personalized prevention of this disease. Emphasis should be placed on SMI assessment during health screenings, particularly for non-diabetic individuals. Notably, this is a cross-sectional study, so causal relationships between SMI and KS cannot be established. Future prospective cohort studies are warranted to validate the causal relationship between SMI and KS and to explore the underlying mechanisms.