Food-based healthy diet metrics, type 2 diabetes, and insulin resistance in ELSA-Brasil: a prospective study of over 12,000 Brazilians

The Global Diet Quality Score (GDQS), the Global Dietary Recommendations score (GDR), Nova-UPF score, and Minimum Diet Diversity for Women (MDD-W) were listed by the United Nations as promising food-based metrics to track dietary quality. The aim was to evaluate those diet metrics performances for monitoring diet-related type 2 diabetes risk and insulin resistance in comparison with the Alternative Healthy Eating Index (AHEI). The study included 12,254 participants (56% women; 35-74 years) of the Brazilian Longitudinal Study of Adults Health (ELSA-Brasil) with available dietary, biochemical, sociodemographic and lifestyle data. Diet quality scores were derived from a validated food-frequency questionnaire covering the previous 12 months. Incident diabetes and changes in insulin resistance (HOMA-IR) over time were evaluated, and mediation by body mass index (BMI) was assessed. After an average 8.2y follow-up period (17% attrition; n=10,191), with 1-standard deviation increase in GDQS, GDR, and AHEI, a 5%, 6%, and 7% decrease in incident diabetes was observed with BMI mediation effect of 39.6%, 74.8%, and 59.4%, respectively (p<0.001 for all the analysis). HOMA-IR increase rate over time was higher in the lower quintile of GDQS (p=0.002) and GDR (p<0.001), compared to the upper quintile. As AHEI, GDR, and GDQS had similar performances in monitoring diet-related type 2 diabetes risk, food-based metrics, such as the GDR and the GDQS can be advantageous in lower resources settings and in nations where there is no food composition data availability.