Dietary n-3 fatty acids intake and all-cause and cardiovascular mortality in patients with pre-diabetes and diabetes

Abstract Background While the association between n-3 polyunsaturated fatty acids (PUFA) and cardiovascular events has been thoroughly examined, there is still a scarcity of research regarding their impact on the long-term prognosis in diabetic patients. Method Herein, a total of 16,539 eligible individuals were enrolled from the National Health and Nutrition Examination Survey (NHANES) 2003-2018, and categorized into T1, T2, and T3 based on the tertiles of n-3 PUFA. The Cox proportional risk regression models, Kaplan-Meier curve, and subgroup analysis were conducted to evaluate the association between n-3 PUFA and mortality. Restricted cubic spline (RCS) curves graphically demonstrated the dose-response relationship. Additionally, weighted quantile sum (WQS) models were adopted to measure the mixed and individual effects of n-3 PUFA on mortality. Results Following a median follow-up period of 8.42 years, 3,010 individuals died, with 989 deaths attributed to cardiovascular diseases. Significantly lower risk of all-cause [T2: 0.81 (0.71, 0.92), T3: 0.77 (0.64, 0.94)] and cardiovascular [T2: 0.75 (0.61, 0.93)] mortality was observed after adjusting for multivariable compared to the reference (T1). Meanwhile, the RCS curve revealed a negative non-linear association between the n-3 PUFA and mortality. None of the interactions in any subgroup analysis were statistically significant except for BMI (p for interaction = 0.049). Finally, the WQS analysis demonstrated alpha-linolenic acid (ALA) and docosapentaenoic acid (DPA) as the main contributors to the n-3 PUFA benefits against mortality. Conclusions Increased dietary intake of n-3 PUFA, particularly ALA and DPA, was associated with a reduced risk of all-cause and cardiovascular mortality among Americans with prediabetes and diabetes.