Total fat intake and fatty acid patterns and prediabetes regression: differential effects across phenotypes in a population-based cohort

Abstract

BACKGROUND AND AIM: This cohort study investigated the potential association between dietary fat intakes and returning to normal glucose regulation (NGR) in different prediabetes (Pre-DM) phenotypes. METHODS: A total of 1587 Pre-DM subjects consisting of 60.2% isolated impaired fasting glucose (iIFG), 21% isolated impaired glucose tolerance (iIGT), and 18.8% combined IFG-IGT, were recruited for baseline dietary assessment and were followed for changes in glycemic status (i.e., returned to NGR, remained Pre-DM, or progressed to diabetes) over 9 years. Cox proportional hazard models were used to calculate hazard ratios (HRs) and 95% confidence intervals (CIs) for returning to NGR across categories of fat intake (< 20%, 20-30%, and > 30% of total energy intake), and tertiles of major fat patterns identified through principal component analysis (PCA). RESULTS: The mean age of the participants was 47.2 ± 12.9 years, and 52.2% were men. Over a median of 5.8 years of follow-up, 46.8% of Pre-DM subjects regressed to NGR. Low-fat diet (LFD) was associated with an increased chance of returning to NGR in the iIGT phenotype (HR = 1.44, 95% CI 1.05-1.98). Two major dietary fat patterns, i.e., Mixed Fat Pattern (MFP, whit a higher load of saturated fat, cholesterol, oleic, linoleic, and trans fatty acids) and ω3FP (i.e., loaded heavily on docosahexaenoic, eicosapentaenoic, and α-linolenic acids), extracted by PCA, were corresponded to 58.4% of the total variance of fat intake. In both iIFG and iIGT phenotypes, highest MFP score was inversely associated with NGR (HR = 0.71, 95% CI 0.50-0.99 and HR = 0.60, 95% CI 0.37-0.97), while the highest ω3FP score was associated with an elevated incidence of NGR in subjects with combined IFG-IGT phenotype by twofold (HR = 2.29, 95% CI 1.00-5.29). CONCLUSIONS: Subjects with iIGT phenotype may take more advantage from adhering a LFD. Dietary fat patterns may differentially affect chance of returning to NGR across Pre-DM phenotypes.