Association between fatty acids and the risk of impaired glucose tolerance and type 2 diabetes mellitus in American adults: NHANES 2005–2016

Background: Fatty acids (FAs) play a major role in regulating insulin sensitivity, but quantitative dietary assessment challenges have limited prior research on dietary FAs and the risk of impaired glucose tolerance (IGT) and type 2 diabetes mellitus (T2DM). Methods: Using NHANES 2005–2016, we extracted dietary FA intakes and covariates (age, sex, race, education, poverty-to-income ratio, BMI, smoking, hypertension, physical activity) and diabetes outcomes. Multivariable logistic regression assessed associations between FA intake and IGT/T2DM. Results: Among 9,082 adults, after full adjustment, total saturated FA (TSFA) was inversely associated with IGT (OR 0.991, 95% CI 0.985–0.998, P=0.024). Total FA (TFA) intake in quintile 4 was inversely associated with T2DM compared to quintile 1 (OR 0.714, 95% CI 0.532–0.959, P=0.025). Factor analysis identified four FA factors; factor 4 (F4) was inversely associated with T2DM (OR 0.824, 95% CI 0.715–0.949, P=0.029). An unsaturated FA signature (18:1, 18:2, 18:3, 20:1) was identified from F4. Conclusions: Several unsaturated FAs common in natural oils may reduce T2DM risk.