In older adults, higher circulating total long-chain omega 3 fatty acid and DHA levels were associated with lower risk of incident atrial fibrillation (AF), according to recent research published in Circulation. Authors concluded these results highlight the need to evaluate whether increased dietary intake of these fatty acids could be effective for primary prevention of AF.

Prior studies evaluating fish or omgea 3 consumption from dietary questionnaires and incident AF have been conflicting. Circulating levels of omega 3s provide an objective measurement of exposure.

Among 3326 U.S. men and women age 65 or older and free of AF or heart failure at baseline, plasma phospholipid levels of eicosapentaenoic acid (EPA), docosapentaenoic acid (DPA), and docosahexaenoic acid (DHA) were measured at baseline using standardized methods.

Incident AF (789 cases) was prospectively identified from hospital discharge records and study visit electrocardiograms during 31,169 person-years of follow-up (1992-2006). In multivariable Cox models adjusted for other risk factors, the RR in the top versus lowest quartile of total omega 3 (EPA+DPA+DHA) levels was 0.71 (95%CI=0.57-0.89, P-trend=0.004); and of DHA levels, 0.77 (95%CI=0.62-0.96, P-trend=0.01). EPA and DPA levels were not significantly associated with incident AF. Evaluated non-parametrically, both total omega 3 and DHA showed graded and linear inverse associations with incidence of AF. Adjustment for intervening events such as heart failure or myocardial infarction during follow-up did not appreciably alter results.