Causal association of plasma n-3 PUFA with peptic ulcer disease: a two-sample Mendelian randomisation study

Dietary n-3 PUFA may have potential benefits in preventing peptic ulcer disease (PUD). However, data from observational epidemiological studies are limited. Thus, we conducted a Mendelian randomisation analysis to reveal the causal impact of n-3 PUFA on PUD. Genetic variants strongly associated with plasma levels of total or individual n-3 PUFA including plant-derived alpha-linolenic acid and marine-derived EPA, DPA and DHA were enrolled as instrumental variables. Effect size estimates of the n-3 PUFA-associated genetic variants with PUD were evaluated using data from the UK biobank. Per one SD increase in the level of total n-3 PUFA in plasma was significantly associated with a lower risk of PUD (OR = 0<middle dot>91; 95% CI 0<middle dot>85, 0<middle dot>99; P = 0<middle dot>020). The OR were 0<middle dot>81 (95 % CI 0<middle dot>67, 0<middle dot>97) for EPA, 0<middle dot>72 (95 % CI 0<middle dot>58, 0<middle dot>91) for DPA and 0<middle dot>87 (95% CI 0<middle dot>80, 0<middle dot>94) for DHA. Genetically predicted alpha-linolenic acid levels in plasma had no significant association with the risk of PUD (OR = 5<middle dot>41; 95% CI 0<middle dot>70, 41<middle dot>7). Genetically predicted plasma levels of n-3 PUFA were inversely associated with the risk of PUD, especially marine-based n-3 PUFA. Such findings may have offered an effective and feasible strategy for the primary prevention of PUD.