Interactive effects of genetic variants and oral contraceptive use on depression in the UK Biobank

Background Oral contraceptive (OC) use, particularly during adolescence, may increase depression risk in some individuals, but it remains unclear who is susceptible to mood-related side effects and who is not. We aimed to detect single nucleotide polymorphisms (SNPs) and genes that moderate the effect of OC use on depression in young adulthood using data from the UK Biobank. Methods N=202,243 participants were followed from birth to age 23.29 (SD: 2.58) years. We used Cox models for counting processes to test the association between OC use and incident depression in young adulthood, and conducted a genome-wide-by-drug-interaction study (GWDIS) of SNP by OC use interactions alongside a standard genome-wide association study (GWAS) on incident depression in young adulthood. Results Over half of all participants (57.5%) initiated OC and 1.0% received a depression diagnosis during follow up. OC initiators had a 20% higher hazard of incident depression than non-initiators (HR=1.20, 95% CI=1.04-1.37). No SNPs reached genome-wide significance in the GWDIS, though eight showed suggestive interaction signals (p<1e-5). At the gene level, FSIP1 (p=5.90e-5) and EHBP1 (p=6.47e-5) showed suggestive signals, but none passed the genome-wide threshold. No SNPs reached genome-wide significance in the GWAS. Conclusions We did not find evidence for genetic variants that moderate the association between OC initiation and depression. If such effects exist, they are likely to be small and polygenic, suggesting there is currently no solid basis for using genetic data for individualised contraception counselling concerning mood-based side effects.