Plasma Total Homocysteine, Folate, and Vitamin B₁₂ Status in Korean Adults

Abstract

Elevated plasma total homocysteine (tHcy) levels have been established as a risk factor for occlusive cardiovascular disease. Also known is that plasma folate and vitamin B₁₂ influence homocysteine metabolism as cosubstrate and cofactor, respectively. However, not much information is available describing plasma tHcy levels and their relationship to plasma folate and vitamin B₁₂ status in Koreans. We measured the plasma levels of tHcy, folate, and vitamin B₁₂ in 195 adults (99males, 96 females; 23-72y old in the lower middle class). The mean plasma tHcy levels of males, 11.18±3.88, imol/L, was significantly higher (p<0.001) than that of females, 9.20±2.65, imol/L. The distribution of tHcy levels of males showed a wide range, 3-50, imol/L, with a long tail toward higher values. Thus the incidence of hyperhomocysteinemia (≥15μmol/L) in males, 10.1%, was significantly higher (<0.02) than the 2.1% in females. As age increased, plasma tHcy levels tended to be higher in females, Therefore, sex differences in plasma tHcy levels disappeared in subjects over fifty. On the other hand, both plasma folate (6.47±3.06 vs 7.96±3.55 ng/mL, p<0.01) and vitamin B₁₂ levels (537.0±222.0 vs. 664.1±309.8 ng/mL, p<0.01) were significantly lower in males than in females. A plasma folate deficiency (<3.0ng/mL) was found in 6.1% of males and 2.1% of females. And a vitamin B₁₂ deficiency (<150pg/mL) was detected in 2.0% and 1.0%, respectively. Plasma tHcy levels were related with inversely plasma concentrations of folate (r=-0.37249, p<0.001) as well as vitamin B₁₂ (r=-0.22560, p<0.01) in both sexes. Plasma levels of tHcy and the prevalence of hyperhomocysteinemia in Korean adults are similar to findings in the West. Our results indicate that male adults may be in worse condition for cardiovascular disease (CVD) than females. And improving folate and vitamin B₁₂ status may reduce plasma tHcy level, which may be more important in males.