Body mass index in adolescence, risk of type 2 diabetes and associated complications: A nationwide cohort study of men

BACKGROUND: Obesity is a predominant factor in development of type 2 diabetes but to which extent adolescent obesity influences adult diabetes is unclear. We investigated the association between body mass index (BMI) in young men and subsequent type 2 diabetes and how, in diagnosed diabetes, adolescent BMI relates to glycemic control and diabetes complications. METHODS: Baseline data from the Swedish Conscript Register for men drafted 1968–2005 was combined with data from the National Diabetes and Patient registries. Diabetes risk was estimated through Cox regression and Kaplan-Meier survival estimates. Relationships between BMI, glycemic control and diabetes complications were assessed through multiple linear and logistic regression. FINDINGS: Among 1,647,826 men, 63,957 (3·88%) developed type 2 diabetes over a median follow-up of 29.0 years (IQR[21.0–37.0]). The risk of diabetes within 40 years after conscription was nearly 40% in individuals with adolescent BMI ≥35 kg/m(2). Compared to BMI 18·5–<20 kg/m(2) (reference), diabetes risk increased in a linear fashion from HR 1·18(95%CI 1·15–1·21) for BMI 20–<22·5 kg/m(2) to HR 15·93(95%CI 14·88–17·05) for BMI ≥35 kg/m(2), and a difference in age at onset of 11·4 years was seen. Among men who developed diabetes, higher adolescent BMI was associated with higher HbA1c levels and albuminuria rates. INTERPRETATION: Rising adolescent BMI was associated with increased risk of type 2 diabetes diagnosed at a younger age, with poorer metabolic control, and a greater prevalence of albuminuria, all suggestive of worse prognosis.