Purpose: High levels of serum total homocysteine (tHcy), often observed in chronic kidney disease (CKD) patients, are a risk factor for cardiovascular disease. However, little is known about the relationship between tHcy and renal function in healthy individuals. We examined whether tHcy levels are related to renal function in Asian individuals without CKD.
Methods: This cross-sectional study examined 2032 subjects, aged 40-64 years. Individuals with kidney diseases or other conditions that could affect tHcy were excluded. Renal function was determined by estimated glomerular filtration rate (eGFR) from levels of serum creatinine (sCr) and cystatin C.
Results: Age, tHcy, sCr, and cystatin C of the subjects were 54.1 ± 6.0 years, 9.5 (8.0-11.4) μmol/L, 0.81 ± 0.1 mg/dL, and 0.82 ± 0.1 mg/L, respectively. In a multiple linear regression analysis, tHcy was a significant independent determinant of sCr and cystatin C in men (β = 0.206 and β = 0.282, respectively) and women (β = 0.247 and β = 0.229, respectively). Highest tHcy levels were independently associated with increased cystatin C (>s1.10 mg/L) with an odds ratio (OR) of 5.00 [95% confidence interval (CI) 2.81-8.09] and decreased eGFR (<90 mL/min/1.73 m(2)) with an OR of 1.69 (95% CI 1.36-2.11) compared to tHcy levels in the 1st-3rd quartiles.
Conclusions: Higher levels of tHcy are independently associated with sCr and cystatin C elevation. Our study suggests that tHcy levels may be influenced by renal function in Asian populations without CKD. Future studies are needed to define the role of tHcy in renal function.
Keywords: Cystatin C; Glomerular filtration rate; Homocysteine; Kidney function test; Serum creatinine.