Child and adolescent obesity: epidemiology and developmental perspectives.

From infancy through adolescence, more and more children are becoming overweight. National prevalence data show that more than 17% of youth have a body mass index (BMI) above the 95th percentile of the US age and sex-specific reference. Particularly alarming are rates in children as young as 2 years of age, and among minority children. Periods of heightened vulnerability to weight gain have been identified, and research supports the notion that obesity has its origins in early life. This paper focuses on susceptibility to increased adiposity during the prenatal period, infancy, mid-childhood and adolescence, and how factors operating in each of these periods influence risk of becoming overweight. Prenatal exposure to over or undernutrition, rapid growth in early infancy, an early adiposity rebound in childhood, and early pubertal development have all been implicated in the development of obesity. The persistence of obesity from young ages emphasizes the importance of understanding growth trajectories, and of developing prevention strategies to overcome strong influences of obesigenic environments at young ages.