Childhood obesity: a new pandemic of the new millennium.

The major epidemiologic transition in the 20th century was the shift in mortality and morbidity from infectious diseases to chronic diseases, with cardiovascular diseases leading the list. This transition was primarily attributable to the social, economic, and public health changes that took place in the United States during the first half of the century. The availability of abundant food led not only to better overall nutriture and improved child health, but also to the current population’s state of excess positive energy balance, accelerated by an increasingly sedentary lifestyle in recent decades. At the beginning of this new millennium, a new challenge has emerged—a marked increase in obesity prevalence with a parallel increase in obesity-associated chronic diseases and their clinical onset at ever younger ages. Type 2 diabetes, a condition traditionally associated with middle-aged adults, is beginning to occur several decades earlier as obesity afflicts an ever greater number of children and adolescents in the United States.1–5 A recent publication in Pediatrics presented longitudinal findings from a large multicenter cohort study—the National Heart, Lung, and Blood Institute Growth and Health Study (NGHS)—of 1213 black and 1166 white girls followed for 9 years from ages 9 to 10.6 As can be seen in the accompanying study in this issue by Kimm et al,7 even at age 9, the prevalence of overweight (≥85th percentile of body mass index [BMI] based on the National Health Examination Survey reference population) was about one third higher in black girls than in white girls—31% versus 22%. The prevalence of obesity (≥95th percentile) in black girls was twice as high than in white girls—18% versus 8%. A most alarming finding in this study was the approximate doubling of the rate of overweight and obesity in both groups during the 10 years between ages …