Association of obesity phenotypes in adolescents and incidence of early adulthood type 2 diabetes mellitus: Tehran lipid and glucose study

Objective Obesity and metabolic syndrome, which has an increasing prevalence among adolescence, are associated with metabolic abnormalities. This study investigates the role of adolescent obesity phenotypes in predicting the incidence of early adulthood type 2 diabetes mellitus (T2DM). Research Design and Methods Participants were divided into four obesity phenotypes: Metabolically healthy normal weight (MHNW), metabolically healthy obese (MHO), metabolically unhealthy normal weight (MUNW), and metabolically unhealthy obese (MUO). Multivariate-adjusted hazard ratios (HRs) were calculated for T2DM incidence. Results In this cohort study, 2306 Tehranian adolescents with an average age of 15.1 +/- 2.4 years were included. The median (IQ 25-75) follow-up was 15.5 (12.8-17.1) years and the median (IQ 25-75) age of participants at the end of follow-up was 30 (26-32) years old. The incidence rate of T2DM during the early adulthood was [1.37 (95% CI: 0.89-2.10)] and [3.18 (95% CI: 2.44-4.16)] per 1000 person per year in boys and girls, respectively. MHO phenotype was not associated with an increased risk of T2DM for both sexes. Adjusted HRs for MUO were [4.30 95% CI (1.48-12.43)] and [3.39 95% CI (1.78-6.45)] in boys and girls, respectively. MUNW phenotype was associated with an increased risk of T2DM only in boys. After adjustment for adulthood BMI, all the phenotypes for both sexes lost their significance, except for boys with MUNW phenotype [HR = 3.46 95% CI (1.15-10.45)]. Conclusions Unhealthy obesity phenotypes; in contrast with MHO; had an increased risk of T2DM incidence, apart from girls with MUNW. After adjusting the adulthood BMI, all phenotypes turn insignificant, except for boys with MUNW.