Folate and vitamin B6 intake and risk of acute myocardial infarction in Italy

Background: Folate and vitamin B-6 intake has been associated with reduced risk of coronary heart disease, but studies are not consistent. Objective: The relation between folate and vitamin B-6 intake and the risk of acute myocardial infarction (AMI) was assessed in a Mediterranean population. Design: A hospital-based case-control study was conducted in Milan, Italy, between 1995 and 1999. Information was collected by interviewer-administered questionnaires. Adjusted odds ratios (ORs) and 95% confidence intervals (CI) were obtained by multiple logistic regression models. Subjects: Cases were 507 patients with a first episode of nonfatal AMI, and controls were 478 patients admitted to hospital for acute conditions. Results: Compared to patients in the lowest tertile of intake, the ORs for those in the highest tertile were 0.56 (95% CI 0.35-0.88) for folate and 0.34 (95% CI 0.19-0.60) for vitamin B-6. The OR was consistently below unity in strata of sex, age, alcohol, methionine, tobacco smoking, coffee, hypertension and family history of AMI; the inverse association was apparently stronger for vitamin B-6 in regular alcohol drinkers than in no or occasional drinkers. Compared to subjects with a low intake of both micronutrients, the OR was 0.29 for those with a high intake of both. Compared to subjects reporting no or occasional alcohol drinking and low methionine and folate intake, the OR was 0.28 in regular drinkers with high methionine and high folate intake. The corresponding value for vitamin B-6 was 0.25. Conclusions: A high intake of folates, vitamin B-6 and their combination is inversely associated with AMI risk. Sponsorship: Partly supported by "Ministero della Salute'' (Contract No. 177, RF 2001).