Estimated Glomerular Filtration Rate, Nutritional Factors, and Their Relationships With Homocysteine in Community-Dwelling Older Adults.

Age-related renal function decline may contribute to other physiological alterations. This study aimed to examine the associations of kidney function, assessed by estimated glomerular filtration rate (eGFR), and nutritional factors with homocysteine levels in community-dwelling older adults. This cross-sectional study enrolled participants aged ≥ 65 years. Demographic characteristics were collected using questionnaires. Biochemical parameters, including homocysteine, folic acid, vitamin B12, and metabolic disorder indicators, were measured, and eGFR was calculated and categorized into three groups. Homocysteine concentrations were significantly higher in the low and moderate eGFR groups compared with the high eGFR group (median: 16.9 vs. 11.9 vs. 9.3 μM, p < 0.01). Regression analyses indicated that each 1-unit decrease in eGFR was associated with higher homocysteine (β = -0.13, p < 0.01). Conversely, higher folic acid (β = -0.29, p < 0.01) and vitamin B12 (β = -0.003, p < 0.01) levels were significantly associated with lower homocysteine concentrations. These associations remained significant after mutual adjustment, indicating distinct effects of renal function and nutritional factors on homocysteine levels. Moreover, homocysteine levels were positively correlated with waist circumference (r = 0.38, p < 0.01) and triglycerides (r = 0.18, p < 0.05) and inversely correlated with high-density lipoprotein cholesterol (r = -0.27, p < 0.01). The results suggest that renal function and nutritional status are independently associated with homocysteine levels and may contribute to metabolic risk profiles in older adults.