The influence of age, sex, vitamin B(12), folate levels and methylenetetrahydrofolate reductase C677T genetic mutations on plasma homocysteine in the Chinese population.

BACKGROUND AND OBJECTIVES Thromboembolic diseases remain a major cause of morbidity and mortality in most countries. The present study was thus conducted to determine the influences of age, sex, the methylenetetrahydrofolate reductase (MTHFR) gene mutation and the B vitamins on the plasma homocysteine (Hcy) levels in the Chinese. Our previous study found that Chinese carry the same mutation of the methylenetetrahydrofolate reductase (MTHFR) gene described in Western populations, with a 677CAET substitution being another possible cause of thrombosis. DESIGN AND METHODS The study population comprised 445 consecutively enrolled Chinese subjects of different ages and sex. Overall 69 subjects were found to have homozygous 677CAET mutation of the MTHFR gene, and were classified as Group I; 164 subjects were found to have heterozygous mutation and classified as Group II; 212 had no such mutation and were classified as Group III. RESULTS The mean plasma Hcy did not differ significantly between these 3 groups. When each group was divided again by gender, we found that both age and plasma Hcy levels were significantly higher in the males than in the females. In addition to Hcy levels, we also measured plasma vitamin B(12) and folate levels in 258 randomized subjects. Univariate and multivariate analysis showed MTHFR mutation could affect Hcy level, and univariate and multivariate analysis showed that age, MTHFR mutation and vitamin B(12) could affect the log(Hcy) levels. INTERPRETATION AND CONCLUSIONS We demonstrate that some Chinese carry the 677CAET mutation of the methylenetetrahydrofolate reductase gene. This could affect their homocysteine levels and thus be a risk factor for thromboembolic disease.