BMI > or = 50 kg/m2 is associated with a younger age of onset of overweight and a high prevalence of adverse metabolic profiles.

Objective: To study the demographic and clinical parameters of three different categories of obesity, with particular focus on a cohort of individuals with BMI > or = 50 kg/m2, the fastest growing category of obesity.

Design: Over 700 obese individuals were studied (186 with BMI = 30-39 kg/m2, 316 with BMI = 40-49 kg/m2 and 290 with BMI > or = 50 kg/m2).

Results: Median BMI was 51 kg/m2 for patients who reported onset of overweight before 15 years of age, 47 kg/m2 for patients who reported onset between 15 and 30 years, and 42 kg/m2 for patients who became overweight after 30 years of age.