Myocardial Infarction in Young Women in Relation to Plasma Total Homocysteine, Folate, and a Common Variant in the Methylenetetrahydrofolate Reductase Gene

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Abstract
Background In a population-based study, we examined the relationship between the risk of myocardial infarction (MI) among young women and plasma total homocysteine (tHCY), folate, vitamin B 12 , and a common cytosine (C) to thymine (T) polymorphism in the gene for 5,10-methylenetetrahydrofolate reductase (MTHFR). Methods and Results In-person interviews and nonfasting blood samples were obtained from 79 women P =.0004) and lower mean folate concentrations (12.4±13.4 versus 16.1±12.2 nmol/L, P =.018). There was no difference in vitamin B 12 concentrations between case patients and control subjects (346.8±188.4 versus 349.7±132.4 pmol/L, P =.90). After adjusting for cardiovascular risk factors, we found that women with tHCY ≥15.6 μmol/L were at approximately twice the risk of MI as women with tHCY 12 concentration. Among control subjects, 12.7% were homozygous for the MTHFR T 677 allele, and these women had higher plasma tHCY and lower plasma folate than women with other genotypes. Ten percent of case patients were homozygous for te T 677 allele, and there was no association of homozygosity for T 677 with MI risk (OR, 0.90; 95% CI, 0.31 to 2.29). Conclusions These data support the hypothesis that elevated plasma tHCY and low plasma folate are risk factors for MI among young women. Although homozygosity for MTHFR T 677 is related to increased plasma tHCY and low plasma folate, this genetic characteristic is not a risk factor for MI in this population.