Red blood cell membrane α-linolenic acid and the risk of sudden cardiac arrest

Higher levels of long-chain n-3 polyunsaturated fatty acids in red blood cell membranes are associated with lower risk of sudden cardiac arrest. Whether membrane levels of α-linolenic acid, a medium-chain n-3 polyunsaturated fatty acid, show a similar association is unclear. We investigated the association of red blood cell membrane α-linolenic acid with sudden cardiac arrest risk in a population-based case-control study. Cases, aged 25 to 74 years, were out-of-hospital sudden cardiac arrest patients attended by paramedics in Seattle, WA (n = 265). Controls, matched to cases by age, sex, and calendar year, were randomly identified from the community (n = 415). All participants were free of prior clinically diagnosed heart disease. Blood was obtained at the time of cardiac arrest (cases) or at the time of an interview (controls). Higher membrane α-linolenic acid was associated with a higher risk of sudden cardiac arrest: after adjustment for matching factors and smoking, diabetes, hypertension, education, physical activity, weight, height, and total fat intake, the odds ratios corresponding to increasing quartiles of α-linolenic acid were 1.7 (95% confidence interval [CI], 1.0-3.0), 1.9 (95% CI, 1.1-3.3), and 2.5 (95% CI, 1.3-4.8) compared with the lowest quartile. The association was independent of red blood cell levels of long-chain n-3 fatty acids, trans-fatty acids, and linoleic acid. Higher membrane levels of α-linolenic acid are associated with higher risk of sudden cardiac arrest.