High concentrations of polyunsaturated n-3 fatty acids in serum are inversely associated with risk of future incident venous thromboembolism - the HUNT cohort study.

BACKGROUND: Previous studies on the association between n-3 (ω-3) polyunsaturated fatty acids (n-3 PUFAs) and risk of venous thromboembolism (VTE), mainly derived from self-reported dietary intake of n-3 PUFAs, have shown mixed results. OBJECTIVES: The aim of this cohort study was to investigate the association between measured serum n-3 PUFA concentrations and risk of first-ever VTE. METHODS: The present cohort (N = 17,087) was derived from the third survey of the Trøndelag Health Study and consisted of individuals aged ≥20 y without previous VTE. Serum n-3 PUFA concentrations were measured in blood drawn at inclusion (2006-2008) using a nuclear magnetic resonance metabolomic platform (Nightingale), and participants were followed until an objectively verified first-ever VTE event, death, migration, or 31 December, 2019. Cox regression was used to estimate hazard ratios (HRs) with 95% confidence intervals (CIs). RESULTS: During a median follow-up of 12 y, 340 experienced an incident VTE event. Participants with n-3 PUFA concentrations in the highest tertile had 28% lower relative risk of VTE (HR: 0.72; 95% CI: 0.54, 0.96) than those with n-3 PUFAs in the lowest tertile in age-adjusted analysis. The inverse association was most pronounced for provoked VTE (HR: 0.62; 95% CI: 0.44, 0.87) and deep vein thrombosis (HR: 0.61; 95% CI: 0.40, 0.93). HRs remained virtually unaffected after further adjustment for sex, body mass index, and history of cardiovascular disease or cancer at baseline. CONCLUSIONS: Our finding of an inverse association between serum n-3 PUFA concentrations and VTE suggest that a diet enriched with n-3 PUFAs might protect against future VTE.