Long-chain n-3 and n-6 polyunsaturated fatty acids and risk of atrial fibrillation: Results from a Danish cohort study.

BACKGROUND: Studies of the relation between polyunsaturated fatty acids and risk of atrial fibrillation have been inconclusive. The risk of atrial fibrillation may depend on the interaction between n-3 and n-6 polyunsaturated fatty acids as both types of fatty acids are involved in the regulation of systemic inflammation. OBJECTIVE: We investigated the association between dietary intake of long chain polyunsaturated fatty acids (individually and in combination) and the risk of atrial fibrillation with focus on potential interaction between the two types of polyunsaturated fatty acids. DESIGN: The risk of atrial fibrillation in the Diet, Cancer and Health Cohort was analyzed using the pseudo-observation method to explore cumulative risks on an additive scale providing risk differences. Dietary intake of long chain polyunsaturated fatty acids was assessed by food frequency questionnaires. The main analyses were adjusted for the dietary intake of n-3 α-linolenic acid and n-6 linoleic acid to account for endogenous synthesis of long chain polyunsaturated fatty acids. Interaction was assessed as deviation from additivity of absolute association measures (risk differences). RESULTS: Cumulative risks in 15-year age periods were estimated in three strata of the cohort (N = 54,737). No associations between intake of n-3 or n-6 long chain polyunsaturated fatty acids and atrial fibrillation were found, neither when analyzed separately as primary exposures nor when interaction between n-3 and n-6 long chain polyunsaturated fatty acids was explored. CONCLUSION: This study suggests no association between intake of long chain polyunsaturated fatty acids and risk of atrial fibrillation.

Association of Plasma Phospholipid n-3 and n-6 Polyunsaturated Fatty Acids with Type 2 Diabetes: The EPIC-InterAct Case-Cohort Study.

BACKGROUND: Whether and how n-3 and n-6 polyunsaturated fatty acids (PUFAs) are related to type 2 diabetes (T2D) is debated. Objectively measured plasma PUFAs can help to clarify these associations. METHODS AND FINDINGS: Plasma phospholipid PUFAs were measured by gas chromatography among 12,132 incident T2D cases and 15,919 subcohort participants in the European Prospective Investigation into Cancer and Nutrition (EPIC)-InterAct study across eight European countries. Country-specific hazard ratios (HRs) were estimated using Prentice-weighted Cox regression and pooled by random-effects meta-analysis. We also systematically reviewed published prospective studies on circulating PUFAs and T2D risk and pooled the quantitative evidence for comparison with results from EPIC-InterAct. In EPIC-InterAct, among long-chain n-3 PUFAs, α-linolenic acid (ALA) was inversely associated with T2D (HR per standard deviation [SD] 0.93; 95% CI 0.88-0.98), but eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) were not significantly associated. Among n-6 PUFAs, linoleic acid (LA) (0.80; 95% CI 0.77-0.83) and eicosadienoic acid (EDA) (0.89; 95% CI 0.85-0.94) were inversely related, and arachidonic acid (AA) was not significantly associated, while significant positive associations were observed with γ-linolenic acid (GLA), dihomo-GLA, docosatetraenoic acid (DTA), and docosapentaenoic acid (n6-DPA), with HRs between 1.13 to 1.46 per SD. These findings from EPIC-InterAct were broadly similar to comparative findings from summary estimates from up to nine studies including between 71 to 2,499 T2D cases. Limitations included potential residual confounding and the inability to distinguish between dietary and metabolic influences on plasma phospholipid PUFAs. CONCLUSIONS: These large-scale findings suggest an important inverse association of circulating plant-origin n-3 PUFA (ALA) but no convincing association of marine-derived n3 PUFAs (EPA and DHA) with T2D. Moreover, they highlight that the most abundant n6-PUFA (LA) is inversely associated with T2D. The detection of associations with previously less well-investigated PUFAs points to the importance of considering individual fatty acids rather than focusing on fatty acid class.

Fish oil intake compared with olive oil intake in late pregnancy and asthma in the offspring: 16 y of registry-based follow-up from a randomized controlled trial.

BACKGROUND: Evidence suggests that asthma is rooted in the intrauterine environment and that intake of marine n-3 polyunsaturated fatty acids (n-3 PUFAs) in pregnancy may have immunomodulatory effects on the child. OBJECTIVE: Our aim was to examine whether increasing maternal intake of n-3 PUFAs in pregnancy may affect offspring risk of asthma. DESIGN: In 1990, a population-based sample of 533 women with normal pregnancies were randomly assigned 2:1:1 to receive four 1-g gelatin capsules/d with fish oil providing 2.7 g n-3 PUFAs (n = 266); four 1-g, similar-looking capsules/d with olive oil (n = 136); or no oil capsules (n = 131). Women were recruited and randomly assigned around gestation week 30 and asked to take capsules until delivery. Among 531 live-born children, 528 were identified in registries and 523 were still alive by August 2006. Diagnoses from the International Coding of Diseases version 10 were extracted from a mandatory registry that recorded diagnoses reported from hospital contacts. RESULTS: During the 16 y that passed since childbirth, 19 children from the fish oil and olive oil groups had received an asthma-related diagnosis; 10 had received the diagnosis allergic asthma. The hazard rate of asthma was reduced by 63% (95% CI: 8%, 85%; P = 0.03), whereas the hazard rate of allergic asthma was reduced by 87% (95% CI: 40%, 97%; P = 0.01) in the fish oil compared with the olive oil group. CONCLUSION: Under the assumption that intake of olive oil in the dose provided here was inert, our results support that increasing n-3 PUFAs in late pregnancy may carry an important prophylactic potential in relation to offspring asthma.