The authors report no relevant financial disclosures.
Risk for incident atrial fibrillation was higher in those who habitually used fish oil supplementation compared with those who did not, researchers reported in the European Journal of Preventive Cardiology.
Further, genetic AF predisposition, no diagnosis of CVD at baseline and background oily fish consumption did not change the association found between fish oil supplementation and AF risk, according to researchers.
“The general population should be informed of the potential AF risks with fish oil supplementation; and the physicians should balance the risk-benefit ratio with fish oil supplementation given that the cardiovascular benefit of fish oil supplementation is indetermined in prior clinical trials,” Junguo Zhang, PhD, postdoctoral researcher from the department of epidemiology, School of Public Health at Sun Yat-sen University in Guangzhou, China, and colleagues wrote.
In a large prospective longitudinal cohort study, Zhang and colleagues evaluated 468,665 participants from the UK Biobank cohort who did not have AF to observe the relationship between fish oil supplementation and AF risk.
Researchers analyzed subgroups of genetic AF risk, baseline CVD and background oily fish consumption to observe any changes in this association.
For genetic AF risk, participants were stratified into low, intermediate and high groups.
In the cohort, the mean age was 57 years, and 45% were men. At baseline, 31.6% of participants informed the researchers of habitual fish oil supplementation, and 5% had CVD.
Median follow-up time was 11.1 years, and in that time, researchers found that those who used fish oil had a 6.2% rate of incident AF compared with a 5.2% rate in nonusers (adjusted HR = 1.1; 95% CI, 1.07-1.13).
The rate of incident AF in all genetic-risk groups was higher in fish oil users than in nonusers (low genetic risk, 3.7% vs. 3%; aHR = 1.08; 95% CI, 1.01-1.16; intermediate genetic risk, 5.8% vs. 4.8%; aHR = 1.1; 95% CI, 1.06-1.14; high genetic risk, 9.8% vs. 8.1%; aHR = 1.11; 95% CI, 1.06-1.15), the researchers found.
This higher rate of incident AF in fish oil users was observed in those without CVD at baseline (5.3% vs. 4.1%; aHR = 1.13; 95% CI, 1.1-1.17; P < .0001) but not in those with CVD at baseline (11.6% vs. 11.1%; aHR = 1.01; 95% CI, 0.97-1.06; P = .56; P for interaction < .0001).
The relationship between fish oil use and AF risk was not modified by frequency of oily fish consumption (P for interaction = .62), according to the researchers.
“Future clinical trials examining the effects of fish oil supplementation on the risk of incident AF should consider a longer duration of follow-up,” Zhang and colleagues wrote.