PREVIEW (Prevention of Diabetes Through Lifestyle Intervention and Population Studies in Europe and Around the World) study in children aged 10 to 17 years: Design, methods and baseline results.

Insulin resistance (IR) in adolescence is associated with type 2 diabetes mellitus [T2DM]. The PREVIEW (Prevention of Diabetes Through Lifestyle Intervention and Population Studies in Europe and Around the World) study assessed the effectiveness of a high-protein, low-glycaemic-index diet and a moderate-protein, moderate-glycaemic-index diet to decrease IR in insulin-resistant children who were overweight or obese. Inclusion criteria were age 10 to 17 years, homeostatic model assessment of IR (HOMA-IR) ≥2.0 and overweight/obesity. In 126 children (mean ± SD age 13.6 ± 2.2 years, body mass index [BMI] z-score 3.04 ± 0.66, HOMA-IR 3.48 ± 2.28) anthropometrics, fat mass percentage (FM%), metabolic characteristics, physical activity, food intake and sleep were measured. Baseline characteristics did not differ between the groups. IR was higher in pubertal children with morbid obesity than in prepubertal children with morbid obesity (5.41 ± 1.86 vs 3.23 ± 1.86; P = .007) and prepubertal and pubertal children with overweight/obesity (vs 3.61 ± 1.60, P = .004, and vs 3.40 ± 1.50, P < .001, respectively). IR was associated with sex, Tanner stage, BMI z-score and FM%. Fasting glucose concentrations were negatively associated with Baecke sport score (r = -0.223, P = .025) and positively with daytime sleepiness (r = 0.280, P = .016) independent of sex, Tanner stage, BMI z-score and FM%. In conclusion, IR was most severe in pubertal children with morbid obesity. The associations between fasting glucose concentration and Baecke sport score and sleepiness suggest these might be possible targets for diabetes prevention.