title: Serum bilirubin as a predictor of incident metabolic syndrome: a 4-year retrospective longitudinal study of 6205 initially healthy Korean men.
abstract: OBJECTIVE
  Serum bilirubin is an endogenous antioxidant with anti-inflammatory properties. Several cross-sectional studies have reported that bilirubin was negatively associated with oxidative stress-mediated diseases, including the metabolic syndrome (MetS). However, the clinical relevance of bilirubin as a risk factor for incident MetS remains controversial. For this reason, the longitudinal effects of baseline serum bilirubin concentrations on incident MetS were evaluated in Korean men.
  
  
  METHODS
  This 4-year retrospective longitudinal observational study involved 6205 Korean men without MetS. Subjects underwent routine health examinations in 2007 and returned for a follow-up examination in 2011. Baseline serum bilirubin concentrations were determined using the vanadate oxidation method.
  
  
  RESULTS
  During the 4-year period, 936 cases of incident MetS (15.1%) were identified. Its incidence decreased across baseline bilirubin quartile categories (P<0.001), with an odds ratio (OR) for developing MetS being significantly lower in the highest quartile group (≥ 1.40 mg/dL) compared with the lowest (≤ 0.90 mg/dL) after adjusting for all confounding variables [OR=0.70, 95% confidence interval (CI) 0.54-0.90; P for trend=0.019]. Among individual components of MetS, bilirubin was found to be negatively associated with only the risk of incident hypertriglyceridaemia. The OR (95% CI) for incident hypertriglyceridaemia in the highest vs lowest quartile was 0.75 (0.61-0.91; P for trend=0.002).
  
  
  CONCLUSIONS
  Serum total bilirubin level was negatively associated with incidence of MetS in healthy Korean men over a 4-year period.
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: M J
authors.initials: MJ
authors.lastname: Lee
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: C H
authors.initials: CH
authors.lastname: Jung
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: Y M
authors.initials: YM
authors.lastname: Kang
authors.affiliation: Department of Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: J Y
authors.initials: JY
authors.lastname: Hwang
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: J E
authors.initials: JE
authors.lastname: Jang
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: J
authors.initials: J
authors.lastname: Leem
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: J-Y
authors.initials: JY
authors.lastname: Park
authors.affiliation: Department of Health Screening and Promotion Center, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea.
authors.forename: H-K
authors.initials: HK
authors.lastname: Kim
authors.affiliation: Department of Internal Medicine, Asan Medical Center, University of Ulsan College of Medicine, Seoul, Republic of Korea. Electronic address: lwjatlas@naver.com.
authors.forename: W J
authors.initials: WJ
authors.lastname: Lee
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001663:Bilirubin / Q000097:blood*; D006801:Humans; D008137:Longitudinal Studies; D008297:Male; D024821:Metabolic Syndrome / Q000097:blood* / Q000453:epidemiology; D008875:Middle Aged; D056910:Republic of Korea / Q000453:epidemiology; D012189:Retrospective Studies; D055815:Young Adult
chemical_list: D001663:Bilirubin
keywords: Antioxidant; Bilirubin; Metabolic syndrome