Fish Oil Supplement Intake Influences Long-Term Atrial Fibrillation Risk

Hyojeong Ahn, MD

Fish oil supplement intake may increase the long-term risk of atrial fibrillation (AF) in a healthy population, according to new findings presented at the European Society of Cardiology Congress 2022.

The findings suggest the 10-year risk of AF was significantly higher in fish oil users compared with non-users and remained consistent in a propensity-score matched cohort.

“The causal effect of fish oil intake on the risk of AF may depend on the specific types of n­3 polyunsaturated fatty acids (PUFA),” wrote study author Hyojeong Ahn, Seoul National University Hospital.

Inefficient evidence on the risk of AF in healthy individuals taking fish oil supplements led Ahn and colleagues to investigate the epidemiologic and causal relationship between fish oil intake and long-term risk.

Utilizing the population-based UK Biobank, the investigators selected healthy individuals without a history of AF, other cardiac arrhythmias, or cardiovascular disease (CVD). These individuals were additionally not taking lipid-lowering medications or dietary supplements other than fish oil.

The study evaluated the 10-year risk of AF in fish oil users compared with non-users in the total population and propensity-score matched cohort. Ahn and colleagues investigated the causal relationship between n-3 PUFA and AF using a two-sample summary-level Mendelian randomization analysis with fixed effects robust inverse-variance weighted method, using genetic instruments from previous studies genome-wide association studies for n-3 PUFA levels and AF, respectively

Analyses included a total of 338,199 participants, with a mean age of 55.2 ± 8.1 years and 44.3% men. Of this population, 25.0% (n = 118,300) was taking fish oil supplements.

Data show the 10-year risk of AF was significantly higher in the fish oil users than in the non-users (3.83% vs 2.91%; adjusted hazard ratio [HR], 1.05; 95% CI, 1.01 - 1.10; P = .023)).

This result was determined to be consistent in the propensity-score matched cohort (propensity-score matched HR, 1.06; 95% CI, 1.00 - 1.12; P = .043). Investigators noted the increased risk of AF by fish oil supplement was prominent among low-risk individuals with healthy lifestyles.

Moreover, the specific type of n-3 PUFA may influence the effect of fish oil intake on the risk of AF.

Among n-3 PUFA, docosapentaenoic acid (DPA) led to significant causal estimates for increased risk of AF (odds ratio [OR], 1.15; 95% CI, 1.08 - 1.22; P <.001).

Meanwhile, higher eicosapentaenoic acid (EPA) levels were associated with a decrease of AF risk (OR, 0.85; 95% CI, 0.80 - 0.90; P <.001).

The study, “Fish oil supplements increase atrial fibrillation risk in healthy individuals: a population-based cohort study and mendelian randomization analysis,” was presented at ESC 2022.