title: The roles of IL-6, IL-10, and IL-1RA in obesity and insulin resistance in African-Americans.
abstract: OBJECTIVE
  The aim of the study was to investigate the associations between IL-1 receptor antagonist (IL-1RA), IL-6, IL-10, measures of obesity, and insulin resistance in African-Americans.
  
  
  METHODS
  Nondiabetic participants (n = 1025) of the Howard University Family Study were investigated for associations between serum IL (IL-1RA, IL-6, IL-10), measures of obesity, and insulin resistance, with adjustment for age and sex. Measures of obesity included body mass index, waist circumference, hip circumference, waist-to-hip ratio, and percent fat mass. Insulin resistance was assessed using the homeostasis model assessment of insulin resistance (HOMA-IR). Data were analyzed with R statistical software using linear regression and likelihood ratio tests.
  
  
  RESULTS
  IL-1RA and IL-6 were associated with measures of obesity and insulin resistance, explaining 4-12.7% of the variance observed (P values < 0.001). IL-1RA was bimodally distributed and therefore was analyzed based on grouping those with low vs. high IL-1RA levels. High IL-1RA explained up to 20 and 12% of the variance in measures of obesity and HOMA-IR, respectively. Among the IL, only high IL-1RA improved the fit of models regressing HOMA-IR on measures of obesity. In contrast, all measures of obesity improved the fit of models regressing HOMA-IR on IL. IL-10 was not associated with obesity measures or HOMA-IR.
  
  
  CONCLUSIONS
  High IL-1RA levels and obesity measures are associated with HOMA-IR in this population-based sample of African-Americans. The results suggest that obesity and increased levels of IL-1RA both contribute to the development of insulin resistance.
authors.affiliation: Center for Research on Genomics and Global Health, National Human Genome Research Institute, National Institutes of Health, Bethesda, Maryland 20892-5635, USA.
authors.forename: Bashira A
authors.initials: BA
authors.lastname: Charles
authors.forename: Ayo
authors.initials: A
authors.lastname: Doumatey
authors.forename: Hanxia
authors.initials: H
authors.lastname: Huang
authors.forename: Jie
authors.initials: J
authors.lastname: Zhou
authors.forename: Guanjie
authors.initials: G
authors.lastname: Chen
authors.forename: Daniel
authors.initials: D
authors.lastname: Shriner
authors.forename: Adebowale
authors.initials: A
authors.lastname: Adeyemo
authors.forename: Charles N
authors.initials: CN
authors.lastname: Rotimi
mesh_terms: D000328:Adult; D001741:Black or African American; D005260:Female; D006801:Humans; D007333:Insulin Resistance; D053590:Interleukin 1 Receptor Antagonist Protein / Q000097:blood*; D016753:Interleukin-10 / Q000097:blood*; D015850:Interleukin-6 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000276:immunology*
chemical_list: D053590:Interleukin 1 Receptor Antagonist Protein; D015850:Interleukin-6; D016753:Interleukin-10