Dietary patterns and the risks of metabolic syndrome and insulin resistance among young adults: Evidence from a longitudinal study

Background and aims: Whether early young adulthood dietary patterns predict the risk of metabolic syndrome (MetS) and diabetes-related endpoints prior to middle age remains unknown. We examined the prospective associations of dietary patterns in early young adulthood with MetS and diabetes-related endpoints at later young adulthood. Methods: We used data of young adults from a long running birth cohort in Australia. The Western dietary pattern rich in meats, refined grains, processed and fried foods and the prudent dietary pattern rich in fruits and vegetables, whole grains and legumes were derived using principal component analysis at the 21-year follow-up from dietary data obtained by a food frequency questionnaire. Fasting blood samples at 30 years were collected from each participant and their blood biomarkers, anthropometric and blood pressure were measured. MetS, insulin resistance, and prediabetes were based on clinical cutoffs; increased b-cell function and insulin resistance were based on upper quartiles. Log-binomial models were used to estimate diet-related risks of each outcome adjusting for potential confounders. Results: Greater adherence to the Western pattern predicted higher risks of MetS (RR: 2.32; 95% CI: 1.34, 4.00), increased insulin resistance (1.69; 1.07, 2.65), high b-cell function (1.60; 1.10, 2.31) and less likelihood of increased insulin sensitivity (0.57; 0.39, 0.84) in adjusted models. Conversely, adhering more to the prudent pattern predicted lower risks of MetS (RR: 0.47; 95% CI: 0.29, 0.75), increased insulin resistance (0.57; 0.39, 0.82), high b-cell function (0.69; 0.50, 0.93) and a greater likelihood of increased insulin sensitivity (1.84; 1.30, 2.60). Conclusion: This prospective study of young adults indicates greater adherence to unhealthy Western diet predicted higher risks of MetS and increased insulin resistance, whereas healthy prudent diet predicted lower risks. Optimizing diets to improve later cardiometabolic health needs to occur in early adulthood.