title: Prevalence and determinants of insulin resistance among U.S. adolescents: a population-based study.
abstract: OBJECTIVE
  We sought to examine the distribution of insulin and homeostasis model assessment of insulin resistance (HOMA-IR) and associations of HOMA-IR with sex, race/ethnicity, age, and weight status, as measured by BMI, among U.S. adolescents.
  
  
  METHODS
  Of 4,902 adolescents aged 12-19 years who participated in the National Health and Nutrition Examination Survey 1999-2002, analysis was performed for a nationally representative subsample of 1,802 adolescents without diabetes who had fasting laboratory measurements. The main outcome measure was HOMA-IR, calculated from fasting insulin and glucose and log transformed for multiple linear regression analyses.
  
  
  RESULTS
  In adjusted regression models that included age and weight status, girls had higher HOMA-IR than boys and Mexican-American children had higher HOMA-IR levels than white children. There were no significant differences in adjusted HOMA-IR between black and white children. Obese children (BMI >/=95th percentile) had significantly higher levels of HOMA-IR compared with children of normal weight (BMI <85th percentile) in adjusted comparisons (mean HOMA-IR 4.93 [95% CI 4.56-5.35] vs. 2.30 [2.21-2.39], respectively). Weight status was by far the most important determinant of insulin resistance, accounting for 29.1% of the variance in HOMA-IR. The prevalence of insulin resistance in obese adolescents was 52.1% (95% CI 44.5-59.8).
  
  
  CONCLUSIONS
  Obesity in U.S. adolescents represents the most important risk factor for insulin resistance, independent of sex, age, or race/ethnicity. The prevalence of insulin resistance in obese children foreshadows a worrisome trend for the burden of type 2 diabetes in the U.S.
authors.affiliation: 300 NIB, Room 6E05, Campus Box 0456, Ann Arbor, MI 48109-0456, USA. joyclee@umich.edu
authors.forename: Joyce M
authors.initials: JM
authors.lastname: Lee
authors.forename: Megumi J
authors.initials: MJ
authors.lastname: Okumura
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Davis
authors.forename: William H
authors.initials: WH
authors.lastname: Herman
authors.forename: James G
authors.initials: JG
authors.lastname: Gurney
mesh_terms: D000293:Adolescent; D000328:Adult; D017677:Age Distribution; D044383:Black People / Q000706:statistics & numerical data; D015992:Body Mass Index; D002648:Child; D003430:Cross-Sectional Studies; D003924:Diabetes Mellitus, Type 2 / Q000453:epidemiology*; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D008297:Male; D017058:Mexican Americans / Q000706:statistics & numerical data; D009765:Obesity / Q000453:epidemiology*; D015995:Prevalence; D017678:Sex Distribution; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data; D001741:Black or African American