Genetic Variants Modifying the Triglycerides-Lowering Effect of Fish Oil Supplementation: A Genome-Wide Interaction Study

Abstract

ObjectivesTo identify genetic variants that modify the effect of fish oil supplementation on blood lipids, including low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), total cholesterol, and triglycerides. MethodsWe performed a genome-wide interaction study in 73,962 participants of European ancestry from the UK Biobank. Candidate associations were evaluated in a replication study with 7,284 participants from the Atherosclerosis Risk in Communities (ARIC) Study. Meta-analysis was further performed across the two cohorts. ResultsFour novel interaction loci were identified at genome-wide significance in meta-analysis. The lead variant in the GJB6-GJB2-GJA3 gene cluster, rs112803755 (A > G; minor allele frequency = 0.041), shows an interaction effect but not the main effect, suggesting that it would not have been discovered in a typical association study. Fish oil supplementation is associated with a decreased blood level of triglycerides in individuals carrying the minor allele, but with an increased level in homozygotes of the major allele. This locus is significantly associated with higher GJB2 expression of connexin 26 in adipose tissue, while connexin activity is known to change upon exposure to omega-3 fatty acids. Significant interaction effects were also found in three other loci in the genes SLC12A3 (HDL-C), ABCA6 (LDL-C), and MLXIPL (LDL-C), but highly significant main effects are also present. ConclusionsOur study identifies novel interaction effects for four genetic loci and highlights genetic variants in the GJB6-GJB2-GJA3 gene cluster, which modify the effects of fish oil supplementation on lowering blood triglycerides. These findings highlight the need and possibility for personalized nutrition. Funding SourcesThe University of Georgia Research Foundation