title: Serum α-carotene concentrations and risk of death among US Adults: the Third National Health and Nutrition Examination Survey Follow-up Study.
abstract: BACKGROUND
  Much research has been conducted relating total carotenoids--and β-carotene in particular--to risk of cancer and cardiovascular disease (CVD). Limited data are emerging to implicate the important role of α-carotene in the development of CVD or cancer.
  
  
  METHODS
  We assessed the direct relationship between α-carotene concentrations and risk of death among 15,318 US adults 20 years and older who participated in the Third National Health and Nutrition Examination Survey Follow-up Study. We used Cox proportional hazard regression analyses to estimate the relative risk for death from all causes and selected causes associated with serum α-carotene concentrations.
  
  
  RESULTS
  Compared with participants with serum α-carotene concentrations of 0 to 1 μg/dL (to convert to micromoles per liter, multiply by 0.01863), those with higher serum levels had a lower risk of death from all causes (P < .001 for linear trend): the relative risk for death was 0.77 (95% confidence interval, 0.68-0.87) among those with α-carotene concentrations of 2 to 3 μg/dL, 0.73 (0.65-0.83) among those with concentrations of 4 to 5 μg/dL, 0.66 (0.55-0.79) among those with concentrations of 6 to 8 μg/dL, and 0.61 (0.51-0.73) among those with concentrations of 9 μg/dL or higher after adjustment for potential confounding variables. We also found significant associations between serum α-carotene concentrations and risk of death from CVD (P = .007), cancer (P = .02), and all other causes (P < .001). The association between serum α-carotene concentrations and risk of death from all causes was significant in most subgroups stratified by demographic characteristics, lifestyle habits, and health risk factors.
  
  
  CONCLUSIONS
  Serum α-carotene concentrations were inversely associated with risk of death from all causes, CVD, cancer, and all other causes. These findings support increasing fruit and vegetable consumption as a means of preventing premature death.
authors.affiliation: Division of Behavioral Surveillance, Office of Surveillance, Epidemiology, and Laboratory Services, Centers for Disease Control and Prevention, 1600 Clifton Rd NE, MS E97, Atlanta, GA 30333, USA. cli@cdc.gov
authors.forename: Chaoyang
authors.initials: C
authors.lastname: Li
authors.forename: Earl S
authors.initials: ES
authors.lastname: Ford
authors.forename: Guixiang
authors.initials: G
authors.lastname: Zhao
authors.forename: Lina S
authors.initials: LS
authors.lastname: Balluz
authors.forename: Wayne H
authors.initials: WH
authors.lastname: Giles
authors.forename: Simin
authors.initials: S
authors.lastname: Liu
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D002338:Carotenoids / Q000097:blood*; D002851:Chromatography, High Pressure Liquid; D005260:Female; D006306:Health Surveys; D006801:Humans; D008297:Male; D008875:Middle Aged; D009026:Mortality; D016016:Proportional Hazards Models; D012306:Risk; D014481:United States
chemical_list: D002338:Carotenoids; C041635:alpha-carotene