Elevated plasma homocysteine: cause or consequence of myocardial infarction?

Abstract

To determine whether a first myocardial infarction leads to increased plasma homocysteine concentrations and whether the association between homocysteine and myocardial infarction was greater at follow-up compared with baseline. A population-based, prospective, nested case-referent study. Screening took place at the nearest health survey centre in northern Sweden. Of more than 36,000 persons screened, 78 developed a first myocardial infarction (average 18 months after sampling). Fifty of these had participated in a follow-up health survey (average 8(1/2) years between surveys) and were sex- and age-matched with 56 referents. Comparison of plasma homocysteine levels in case and referent subjects before and after development of a first myocardial infarction. No statistically significant difference was found between cases and referents regarding homocysteine at baseline or follow-up. Plasma homocysteine and plasma creatinine increased significantly, and plasma albumin decreased significantly over time. Conditional univariate logistic regression indicated that high homocysteine at follow-up but not baseline was associated with first myocardial infarction (OR 2.49; 95% CI: 1.03-6.02), but the relation disappeared in multivariate analyses including plasma creatinine and plasma albumin. High plasma creatinine remained associated with first myocardial infarction at both baseline (OR 2.94; 95% CI: 1.05-8.21) and follow-up (OR 3.38; 95% CI: 1.21-9.48). In this study, first myocardial infarction did not cause increased plasma homocysteine concentration.