title: Demographic and socioeconomic correlates of adiposity assessed with dual-energy X-ray absorptiometry in US children and adolescents.
abstract: BACKGROUND
  Associations between demographic-socioeconomic characteristics and childhood obesity are complex in the United States.
  
  
  OBJECTIVE
  We examined associations between demographic-socioeconomic characteristics (age, sex, race-ethnicity, family income, household size, and birthplace) and adiposity measured by dual-energy X-ray absorptiometry in US children.
  
  
  METHODS
  Data were from 8-19-y-old US children enrolled in NHANES 2001-2004 (n = 5436). Adiposity was expressed as the fat mass index (FMI = fat mass/height(2); in kg/m(2)), percentage body fat (%BF), and prevalence of normal, overfat, and excess fat corresponding to %BF <25%, 25-29.9%, and ≥30% in boys and <30%, 30-34.9%, and ≥35% in girls, respectively. We used sex-specific linear and multinomial logistic regression models adjusted for demographic-socioeconomic factors.
  
  
  RESULTS
  The prevalence of excess fat was higher in Mexican American (36%) than in white (28%; P ≤ 0.10) and black (21%; P < 0.05) boys; higher in Mexican American (44%) than in white (36%; P ≤ 0.10) and black (35%; P < 0.05) girls; and higher in US-born (38%) than in foreign-born (29%; P ≤ 0.10) Mexican American boys. In boys, %BF was higher in Mexican Americans and lower in blacks than in whites (P < 0.05). Adiposity was negatively associated with family income in white boys and girls and in Mexican American girls (P < 0.05). Racial-ethnic disparities in adiposity persisted (P < 0.001) after control for demographic-socioeconomic factors available in NHANES. The R(2) for sex-specific models of %BF or FMI regressed on age, race-ethnicity, family income, household size, and birthplace ranged from 2% to 11%.
  
  
  CONCLUSIONS
  The association between demographic-socioeconomic factors and adiposity among US children varied substantially by age, sex, and race-ethnicity.
authors.affiliation: Johns Hopkins Global Center on Childhood Obesity and Center for Human Nutrition, Department of International Health, Johns Hopkins Bloomberg School of Public Health, Baltimore, MD, USA.
authors.forename: Nguyen T
authors.initials: NT
authors.lastname: Tuan
authors.forename: Nancy F
authors.initials: NF
authors.lastname: Butte
authors.forename: Youfa
authors.initials: Y
authors.lastname: Wang
mesh_terms: D015502:Absorptiometry, Photon; D050154:Adiposity / Q000208:ethnology*; D000293:Adolescent; D001741:Black or African American; D002648:Child; D005260:Female; D006801:Humans; D008297:Male; D017058:Mexican Americans; D009749:Nutrition Surveys; D012044:Regression Analysis; D012959:Socioeconomic Factors; D014481:United States; D044465:White People; D055815:Young Adult