Context: Although the prevalence rates of childhood obesity have seemingly been stable over the past few years, far too many children and adolescents are still obese. Childhood obesity, and its associated metabolic complications, is rapidly emerging as one of the greatest global challenges of the 21st century. About 110 million children are now classified as overweight or obese.
Evidence acquisition: In this review we first describe the most recent data on the prevalence, severity, and racial/ethnic differences in childhood obesity. Obesity is associated with significant health problems in the pediatric age group and is an important early risk factor for much of adult morbidity and mortality.
Evidence synthesis: We review the metabolic complications associated with childhood obesity. Particular emphasis is given to the description of studies regarding the impact of varying degrees of obesity on the cardiometabolic risk factors in youth. We further describe studies in obese adolescents that have examined the importance of ectopic lipid deposition in the visceral abdominal depot and in insulin sensitive tissues in relation to the presence of insulin resistance. We end by describing studies that have examined beta-cell function in obese adolescents with normal glucose tolerance.
Conclusions: The growing number of obese children and adolescents worldwide is of great concern. Many obese children and adolescents already manifest some metabolic complications, and these children are at high risk for the development of early morbidity. Understanding the underlying pathogenesis of this peculiar phenotype is of critical importance.