Serum free fatty acid pattern and risk of myocardial infarction: a case-control study

Objectives. To investigate the association between composition of serum free fatty acid (FFA) fraction and risk of a first myocardial infarction (MI). Design. A case-control design. Setting. The patients were recruited from Ulleval Hospital in Oslo and Ostfold Central Hospital in Fredrikstad and Sarpsborg, Norway. Subjects. A total of 103 patients with first MI and 104 population controls, both men and postmenopausal women, age 45-75 years. Results. The mean molar percentage content of docosahexaenoic (DHA), eicosapentaenoic (EPA), stearic and myristic acid in the serum FFA fraction was significantly lower in cases than in controls, whereas that of oleic and linoleic acid was higher in cases. Increased percentage content of total very long-chain omega-3 fatty acids (VLC n-3) in serum FFA was associated with decreased risk of MI. Multivariate odds ratio (OR), adjusted for age, sex, waist-hip ratio, smoking, family history of coronary heart disease (CHD) and years of education was 0.20 (95% CI 0.06-0.63) for the highest vs. lowest quartile. Also increased content of stearic acid was associated with decreased risk. Multivariate OR adjusted as above was 0.38 (95% CI 0.14-1.04) for the highest versus lowest quartile. After adjustment for oleic acid, however, the inverse linear trend was no longer significant. Conclusions. The percentage content of VLC n-3 as well as of stearic acid in serum FFA was inversely associated with risk of myocardial infarction. That of VLC n-3 may reflect diet. but additionally these free fatty acids might in some way be related to the pathogenetic process and not only reflect their content in adipose tissue.