Association between sarcopenia index based on the serum creatinine to cystatin C ratio and cancer incidence in middle-aged and older adults in China: A nationwide cohort study.

OBJECTIVES

To examine the association between a novel sarcopenia index and cancer incidence among Chinese adults aged ≥45 y.

METHODS

Data were derived from the China Health and Retirement Longitudinal Study. The sarcopenia index was calculated as the ratio of serum creatinine (mg/L) to serum cystatin C (mg/L), multiplied by 100. Incident cancer was identified through self-reported physician diagnosis. Cox proportional hazards models were used to estimate the association between the sarcopenia index and cancer risk, evaluated both continuously and by tertiles. Dose-response and linearity were assessed using restricted cubic spline regression and likelihood ratio tests, respectively.

RESULTS

A total of 10 446 participants (median age, 59 y) were included. During a median follow-up of 8.92 y, 248 participants developed cancer. The sarcopenia index was linearly associated with cancer risk. Each 1.0-SD increase in the index was associated with a 2% reduction in cancer risk. Compared with the lowest tertile (T1), adjusted hazard ratios (HRs) were 0.97 (95% CI, 0.73-1.29; P = 0.83) for T2 and 0.58 (95% CI, 0.41-0.83; P < 0.01) for T3 (P for trend < 0.01). Using T3 as the reference, HRs were 1.67 (95% CI, 1.18-2.36; P < 0.01) for T2 and 1.72 (95% CI, 1.21-2.46; P < 0.01) for T1 (P for trend < 0.01).

CONCLUSIONS

A significant inverse association was observed between the sarcopenia index and incident cancer risk in middle-aged and older adults, highlighting the potential role of skeletal muscle health in cancer prevention.