Correlates of plasma total homocysteine concentrations in the post‐folic acid fortification period.

Folic acid intake has significantly increased after fortification of cereals with folic acid in the US. Folate intake is inversely associated with circulating total homocysteine (tHcy). Elevated tHcy is linked to vascular disease risk. We investigated the relationship between plasma tHcy and blood vitamins, BMI, and demographic characteristics in the post‐folic acid fortification period, 1999–2004. For analysis, data from National Health and Nutrition Examination Surveys, 1999–2000, 2001–2002, and 2003–2004 were combined into one analytic database (n=21509; men, 10574; women, 10935). Plasma tHcy concentrations were ≈16% higher in men than in women (9.3 vs 8.0 μmol/L), ≈88% higher in persons aged ≥70y than in persons aged <30y (11.4 vs 6.1 μmol/L), ≈37% higher in 1 st quartile serum vitamin B‐12 than in 4 th quartile serum vitamin B‐12 (9.2 vs 6.7 μmol/L), ≈25% higher in 1 st quartile serum folate than in 4 th quartile serum folate (9.1 vs 7.3 μmol/L), and ≈35% higher in 4 st quartile BMI than in 1 th quartile BMI (8.5 vs 6.3 μmol/L). Race‐ethnicity differences in tHcy were not apparent. In the post‐folic acid fortification period (1999–2004), plasma tHcy was related to sex, age, BMI, serum vitamin B‐12, and serum folate.