title: The relationship between total bilirubin levels and total mortality in older adults: the United States National Health and Nutrition Examination Survey (NHANES) 1999-2004.
abstract: OBJECTIVE
  Due to its anti-oxidant and anti-inflammatory properties, bilirubin has been associated with reduced cardiovascular risk. A recent study demonstrated an L-shaped association of pre-treatment total bilirubin levels with total mortality in a statin-treated cohort. We therefore investigated the association of total bilirubin levels with total mortality in a nationally representative sample of older adults from the general population.
  
  
  METHODS
  A total of 4,303 participants aged ≥ 60 years from the United States National Health and Nutrition Examination Survey 1999-2004 with mortality data followed up through December 31, 2006 were included in this analysis, with a mean follow-up period of 4.5 years.
  
  
  RESULTS
  Participants with total bilirubin levels of 0.1-0.4 mg/dl had the highest mortality rate (19.8%). Compared with participants with total bilirubin levels of 0.5-0.7 mg/dl and in a multivariable regression model, a lower total bilirubin level of 0.1-0.4 mg/dl was associated with higher risk of total mortality (hazard ratios, 1.36; 95% confidence interval, 1.07-1.72; P = 0.012), while higher levels (≥ 0.8 mg/dl) also tended to be associated with higher risk of total mortality, but this did not reach statistical significance (hazard ratios, 1.24; 95% confidence interval, 0.98-1.56; P = 0.072).
  
  
  CONCLUSIONS
  In this nationally representative sample of older adults, the association of total bilirubin levels with total mortality was the highest among those with a level between 0.1 and 0.4 mg/dl. Further studies are needed to investigate whether higher total bilirubin levels could be associated with a higher mortality risk, compared to a level of 0.5-0.7 mg/dl.
authors.affiliation: Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Kwok-Leung
authors.initials: KL
authors.lastname: Ong
authors.affiliation: Department of Family and Preventive Medicine, University of California San Diego, La Jolla, California, United States of America.
authors.forename: Matthew A
authors.initials: MA
authors.lastname: Allison
authors.affiliation: Department of Medicine, University of Hong Kong, Hong Kong, China.
authors.forename: Bernard M Y
authors.initials: BM
authors.lastname: Cheung
authors.affiliation: Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Ben J
authors.initials: BJ
authors.lastname: Wu
authors.affiliation: Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Barter
authors.affiliation: Centre for Vascular Research, University of New South Wales, Sydney, New South Wales, Australia; Faculty of Medicine, University of Sydney, Sydney, New South Wales, Australia.
authors.forename: Kerry-Anne
authors.initials: KA
authors.lastname: Rye
mesh_terms: D000328:Adult; D000368:Aged; D001663:Bilirubin / Q000378:metabolism*; D005260:Female; D006801:Humans; D008297:Male; D009026:Mortality; D009749:Nutrition Surveys; D016016:Proportional Hazards Models; D044469:Racial Groups; D012907:Smoking / Q000453:epidemiology; D016019:Survival Analysis; D014481:United States / Q000453:epidemiology
chemical_list: D001663:Bilirubin
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