Longitudinal effect of the TCF7L2-rs7903146 polymorphism on BMI over a 4-year follow-up period in n = 3141 subjects depending on T2D status: (a) non-diabetic; (b) T2D subjects. Adjusted means BMI depending on the polymorphism (co-dominant model) and T2D at baseline and 1, 2, 3 and 4 years of follow-up in all subjects having data for all the five measurements were estimated from a repeated-measures ANOVA model with interaction terms adjusted for dietary intervention (MedDiet versus control), sex, age, center, BMI, adherence to the Mediterranean diet (AdMedDiet), smoking, drinking, and physical activity at baseline. Adjusted p values for the overall effect of the polymorphism and for the interaction among the polymorphism and T2D, were obtained in the multivariable model.