Plasma homocysteine is adversely associated with glomerular filtration rate in asymptomatic black and white young adults: the Bogalusa heart study

That plasma homocysteine is elevated markedly in renal dysfunction is well recognized. But whether the increased homocysteine is an independent correlate of glomerular filtration rate, a marker of renal function, in asymptomatic younger individuals is not clear. The aim of this study was to determine the association between plasma homocysteine and renal function in a biracial (black-white) community-based cohort of asymptomatic young adults. Plasma homocysteine along with cardiovascular disease risk factor variables were measured in 805 white and 330 black subjects, ages 24-44 years, enrolled in the Bogalusa Heart Study. Modification of Diet in Renal Disease Study equation was used to calculate the estimated glomerular filtration rate (eGFR) from serum creatinine level. Males versus females showed higher homocysteine levels (8.83 +/- 3.16 vs. 7.35 +/- 2.84 micromol/L, p < 0.0001) and lower eGFR (99.1 +/- 17.6 vs. 102.5 +/- 21.0 mL/min/1.73 m(2), p = 0.024). Whites versus blacks had lower eGFR (97.3 +/- 18.0 vs. 110.0 +/- 20.6 mL/min/1.73 m(2), p < 0.0001). In a multivariate regression analysis that included age, race, sex, body mass index, blood pressure, lipoprotein variables, insulin resistance index and homocysteine, white race, age and homocysteine, in that order, were independently and negatively associated with eGFR. The odds ratio (95% confidence interval) of individuals in the homocysteine quintiles II, III, IV and V vs. I for having the risk of impaired eGFR defined as <10th percentile was 2.28 (0.95-5.50, p = 0.065), 2.97 (1.24-7.12, p = 0.015), 3.32 (1.45-7.60, p = 0.005) and 6.99 (3.06-15.94, p < 0.0001), respectively. Homocysteine is an independent correlate of renal function in asymptomatic black and white young adults.