Fish oil supplements increase atrial fibrillation risk in healthy individuals: a population-based cohort study and Mendelian randomization analysis

Background

There is a paucity of information on the risk of atrial fibrillation (AF) in healthy individuals taking fish oil supplements.

Purpose

We aimed to investigate the epidemiologic and causal relationships between fish oil supplement intake and the long-term risk of AF.

Methods

From the population-based UK Biobank, we selected healthy individuals without a history of AF, other cardiac arrhythmias, or cardiovascular diseases, who were not taking lipid-lowering medications or dietary supplements other than fish oil. The 10-year risk of AF in Fish-Oil-Users vs. Non-Users was evaluated in the total population and propensity-score matched cohort. The causal relationship between n-3 polyunsaturated fatty acids (PUFA) and AF was evaluated 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.

Results

A total of 338,199 participants (aged 55.2±8.1, 44.3% men) were analysed. Of these, 35.0% (n=118,300) was taking fish oil supplements. 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=0.023). The result was consistent in the propensity-score matched cohort (propensity-score matched HR 1.06, 95% CI [1.00–1.12], P=0.043). The increased risk of AF by fish oil supplement was prominent in low-risk participants with healthy lifestyles. Among n-3 PUFA, the docosapentaenoic acid (DPA) showed significant causal estimates for the increased risk of AF (odds ratio [OR] 1.15, 95% CI [1.08–1.22], P<0.001), while higher eicosapentaenoic acid (EPA) levels caused a decrease of AF risk (OR 0.85, 95% CI [0.80–0.90], P<0.001).

Conclusion

Fish oil supplement intake significantly increased the long-term risk of AF in a healthy population. The causal effect of fish oil intake on the risk of AF may depend on the specific types of n-3 PUFA.

Funding Acknowledgement

Type of funding sources: None.

Triton burnup measurements in KSTAR using a neutron activation system

Measurements of the time-integrated triton burnup for deuterium plasma in Korea Superconducting Tokamak Advanced Research (KSTAR) have been performed following the simultaneous detection of the d-d and d-t neutrons. The d-d neutrons were measured using a ³He proportional counter, fission chamber, and activated indium sample, whereas the d-t neutrons were detected using activated silicon and copper samples. The triton burnup ratio from KSTAR discharges is found to be in the range 0.01%-0.50% depending on the plasma conditions. The measured burnup ratio is compared with the prompt loss fraction of tritons calculated with the Lorentz orbit code and the classical slowing-down time. The burnup ratio is found to increase as plasma current and classical slowing-down time increase.

Use of silicone fluids in studies of cellular amino acids

In numerous cellular studies, cells labeled with radioisotopes have been separated from the labeling medium by an aqueous solution in order to determine the quantity of internalized labels; however, the aqueous wash tends to remove significant labeling from the cells. Therefore, in order to preserve all of the internalized labels, non-aqueous medium such as silicone fluids may be used. The termination of the labeling is achieved in the silicone method when, upon centrifugation, the cells separate from the medium and enter the silicone fluid to sediment to the tube bottom. This sedimentation of cells placed above a layer of silicone fluid exhibits a critical dependence on the centrifugal force, and gives rise to an uncertainty of only 2 s in determining the time of separation of cells from the medium using General Electric F-50 silicone fluid and a modified Beckman J2-21 centrifuge. It is therefore possible to determine the kinetics of incorporation of labeled amino acids into intracellular pools and proteins. In particular, since this silicone wash method determines the size of the total pool and the aqueous wash method determines the size of the acid-extractable pool, the simultaneous measurements of the size of both pools leads to the determination of the kinetics of labeling of the free amino acid pool. Among many possible applications and extensions of these methods, the studies of formation of intracellular pools and relations among different pools of transported molecules, such as water and amino acids, appear promising.