Association of cystatin C with leptin and TNF-α in elderly Japanese women.

BACKGROUND AND OBJECTIVES Determinants of cystatin C, a novel marker of mortality in the elderly, have not been extensively studied in Asian elderly population. METHODS AND STUDY DESIGN Associations of cystatin C with anthropometric, cardiometabolic, hematological, nutritional variables and inflammatory markers were examined in 159 community-living elderly Japanese women whose BMI averaged 22.6±2.9 (SD) kg/m2. RESULTS Serum creatinine and cystatin C averaged 0.73±0.16 mg/dL and 0.85±0.20 mg/L, respectively. Creatinine-based estimated glomerular filtration rate (standardized β, -0.538, p<0.001), age (standardized β, 0.274, p<0.001), serum leptin (standardized β, 0.218, p<0.001) and tumour necrosis factor-α (TNF-α, standardized β, 0.165, p=0.002) emerged as significant predictors of serum cystatin C independent of percentage body fat, homeostasis model assessment of insulin resistance, high-sensitivity C-reactive protein, systolic blood pressure and HDL cholesterol (cumulative R2=0.674). CONCLUSIONS Elevated serum levels of leptin and TNF-α contributed to elevated cystatin C independent of kidney function, fat mass, insulin resistance and inflammation in community-living elderly women and may represent confounders of associations between cystatin C and mortality in this population.