Dietary intake and adipose tissue content of α-linolenic acid and risk of myocardial infarction: a Danish cohort study

Background: Intake of the plant-derived omega-3 (n-3) fatty acid a-linolenic acid (ALA, 18:3; n-3) may reduce coronary heart disease (CHD) risk, but the results of previous studies have been inconsistent. Objective: We aimed to investigate the association between dietary intake of ALA, adipose tissue content of ALA, and risk of incident myocardial infarction (MI). Design: A total of 57,053 participants, aged 50-64 y, were enrolled in the prospective Danish cohort study Diet, Cancer and Health between 1993 and 1997. Dietary intake of ALA was assessed with the use of a validated semiquantitative food-frequency questionnaire in the full cohort, whereas the adipose tissue content of ALA was determined with the use of gas chromatography in all incident MI cases and in a random sex-stratified sample of the total cohort (n = 3500). Results: During a median of 17 y of follow-up, we identified 2177 male and 912 female cases of MI. After appropriate exclusions, we included 2124 men and 854 women for analyses of dietary intake of ALA, whereas 1994 men and 770 women were included in the analysis of the adipose tissue content of ALA. In multivariate analyses that were conducted with the use of restricted cubic splines and adjusted for established CHD risk factors, weak positive associations in men and weak U-shaped associations in women were shown between both dietary intake and the adipose tissue content of ALA and risk of MI, but these associations were not statistically significant. Additional adjustments for dietary factors did not influence the observed associations numerically. Conclusion: This study suggests that ALA has no appreciable association with risk of incident MI in either men or women.