title: Racial differences in association of elevated interleukin-18 levels with type 2 diabetes: the Atherosclerosis Risk in Communities study.
abstract: OBJECTIVE
  Elevated plasma interleukin-18 (IL-18) has been linked to onset of diabetes mellitus (DM) and its complications. However, so far this association has been shown only in predominantly white populations. We examined IL-18 levels and their association with incident DM in a racially heterogeneous population.
  
  
  METHODS
  In a nested case-cohort design representing a 9-year follow-up of 9,740 middle-aged, initially healthy, nondiabetic white and African American participants of the Atherosclerosis Risk in Communities Study, we selected and measured analytes on race-stratified (50% white, 50% African American) random samples of both cases of incident diabetes (n = 548) and eligible members of the full cohort (n = 536). RESULTS Baseline IL-18 levels were significantly higher in white participants compared with African American participants (P < 0.001). Although white participants in the fourth (versus first) quartile of IL-18 levels had a significant hazard ratio (HR) for developing DM (HR: 2.1, 95% CI: 1.3-3.4), after adjustment for age, sex, and study center, no difference was seen among African Americans (HR: 1.0, 95% CI: 0.6-1.7). Unlike those in African Americans, IL-18 levels in whites had a significant correlation with age (P < 0.01); anthropometric characteristics such as waist circumference (P < 0.001), height (P = 0.04), waist-to-hip ratio (P < 0.001), and BMI (P < 0.01); and total (P < 0.001) and high-molecular-weight (P < 0.001) adiponectin.
  
  
  CONCLUSIONS
  There are racial differences in levels of IL-18 and the association of IL-18 with risk factors and incident type 2 DM. In addition, there seems to be a complex interplay of inflammation and adiposity in the development of DM.
authors.affiliation: Section of Cardiovascular Research, Baylor College of Medicine, and Center for Cardiovascular Disease Prevention, Methodist DeBakey Heart Center, Houston, TX, USA.
authors.forename: Smita I
authors.initials: SI
authors.lastname: Negi
authors.forename: James S
authors.initials: JS
authors.lastname: Pankow
authors.forename: Karl
authors.initials: K
authors.lastname: Fernstrom
authors.forename: Ron C
authors.initials: RC
authors.lastname: Hoogeveen
authors.forename: Na
authors.initials: N
authors.lastname: Zhu
authors.forename: David
authors.initials: D
authors.lastname: Couper
authors.forename: Maria I
authors.initials: MI
authors.lastname: Schmidt
authors.forename: Bruce B
authors.initials: BB
authors.lastname: Duncan
authors.forename: Christie M
authors.initials: CM
authors.lastname: Ballantyne
mesh_terms: D001741:Black or African American / Q000706:statistics & numerical data; D015331:Cohort Studies; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000453:epidemiology / Q000208:ethnology*; D005260:Female; D006801:Humans; D015994:Incidence; D020382:Interleukin-18 / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012306:Risk; D014481:United States / Q000453:epidemiology; D044465:White People / Q000706:statistics & numerical data
chemical_list: D020382:Interleukin-18