Pathophysiology
Clinical meaning
Pediatric obesity results from chronic energy imbalance, but the pathophysiology extends beyond simple caloric excess. Adipocyte hypertrophy and hyperplasia create a pro-inflammatory state with elevated IL-6, TNF-alpha, and leptin resistance, driving insulin resistance even before frank type 2 diabetes develops. In children, obesity during critical periods of adipocyte development (ages 5-7 and adolescence) programs persistent adiposity through epigenetic mechanisms. Unlike adults, BMI is age- and sex-specific in children: overweight = BMI 85th-94th percentile, obesity = BMI โฅ 95th percentile, severe obesity = BMI โฅ 120% of 95th percentile. Pediatric obesity carries unique complications including slipped capital femoral epiphysis, Blount disease (tibia vara), pseudotumor cerebri, and earlier onset of type 2 diabetes with more aggressive beta-cell decline than adult-onset T2DM.