Reference values for plasma homocysteine and folate levels in Korean adults

Plasma total homocysteine (tHcy) is known as an independent risk factor for cardiovascular disease. Folate intake is inversely associated with tHcy. The reference data for tHcy and plasma folate levels, however, are varied by race, ethnicity and country. The aim of this study was to determine the reference values of tHcy and folate levels in Korean adults. Plasma folate and tHcy were measured in a random sample of 1,700 subjects aged 20-74 years (821 men and 879 women) living in two southwestern provinces of South Korea. The geometric mean of tHcy concentration was 8.0 and 5.7 µmol/L for men and women, respectively. The geometric mean of plasma folate concentration was 8.6 and 11.0 ng/ml for men and women, respectively. The mean tHcy concentration observed in our study was lower than those observed in other countries. The folate concentration was higher than those observed in other countries without national folate fortification program. The reasons for relatively low tHcy and high folate concentration are not clear but possibly associated with the Korean diet which tends to be high in green leafy vegetables and other plant foods that are rich in folic acid. The differences in lifestyle factors such as smoking, drinking and coffee consumption may be associated with low tHcy and high folate level. These results suggest that national folate fortification program be introduced based on the epidemiological evidence.