Percent Body Fat and Chronic Disease Risk Factors in US Children and Youth

Background: The dramatic increase in pediatric obesity has renewed interest in accurate methods and screening indexes for identifying at-risk children and youth. Whether age-specific standards are needed is a factor that remains uncertain. Purpose: This study was designed to describe the age-specific fatness-risk factor relationship in boys and girls across a wide age range. Methods: Data were from 12,279 white, black, and Mexican-American children and adolescents from the National Health and Nutritional Examination Surveys (NHANES) III (1998-1994) and IV (1999-2004). Children were grouped based on percent fat, estimated from subscapular and triceps skinfolds, and the age-specific relationships between percent fat and chronic disease risk factors (e. g., blood pressure, lipids and lipoprotein levels, glucose, insulin, and circulating C-reactive protein levels) were described in boys and girls, aged 6-18 years. Results: Percent fat was significantly related to risk factor levels. At higher levels of percent fat, the prevalence of adverse cardiovascular disease risk factors was higher, particularly above 20% fat in boys and above 30% fat in girls. In boys and girls, the interaction term age by percent fat was a significant predictor of risk factors, whereas the percent fat by race interaction term was nonsignificant. Conclusions: The results demonstrate a strong relationship between chronic disease risk factors and percent fat in children and youth that varies by age in boys and girls. (Am J Prev Med 2011; 41(4S2): S77-S86) (C) 2011 American Journal of Preventive Medicine