Does youth adiposity, or change in adiposity from youth to adulthood, predict metabolically healthy obesity in adulthood?

BACKGROUND: Individuals with metabolically healthy obesity (MHO) do not have the metabolic complications usually associated with obesity. OBJECTIVE: To examine whether youth adiposity, or change in adiposity from youth to adulthood, predicts MHO 20 years later. METHODS: A national sample of 2410 Australian participants had height, weight and waist circumference (WC) measured in 1985 (7-15 years old) and 2004-2006 (26-36 years old). A fasting blood sample was taken in 2004-2006. MHO was defined as body mass index (BMI) ≥30 kg m(-2) , normal fasting glucose (<5.6 mmol L(-1) ), triglycerides (<1.695 mmol L(-1) ), high-density lipoprotein-cholesterol (>1.036 mmol L(-1) men, > 1.295 mmol L(-1) women), blood pressure (<130/85 mmHg) and no medication for these conditions. Relative risks (RR) were calculated using log binomial regression and expressed per unit of youth BMI (or WC) z-score or change in BMI (or WC) z-score from youth to adulthood, adjusted for sex and youth age. RESULTS: In total 323 individuals were obese at follow-up, 79 (24.5%) were MHO. Adult MHO was not associated with youth BMI (RR: 1.00, 95%CI: 0.85-1.19) or WC (RR: 0.93, 95%CI: 0.79-1.11). Individuals were less likely to be MHO if they had larger increases in BMI (BMI RR: 0.74, 95%CI: 0.57-0.97) or WC (RR: 0.70, 95%CI: 0.55-0.90) from youth to adulthood. CONCLUSIONS: Change in adiposity from youth to adulthood predicted adult MHO better than youth adiposity alone.