title: Association of blood antioxidants and vitamins with risk of age-related cataract: a meta-analysis of observational studies.
abstract: BACKGROUND
  Observational studies have been inconsistent regarding the association between blood antioxidants or vitamins and risk of age-related cataract.
  
  
  OBJECTIVE
  We performed a meta-analysis to determine whether an association exists between blood levels of antioxidants or vitamins and age-related cataract in observational studies.
  
  
  METHODS
  We searched PubMed, EMBASE, and the Web of Science for relevant studies from inception to October 2012. Study-specific risk estimates were combined by using a random-effects model.
  
  
  RESULTS
  A total of 13 studies with 18,999 participants were involved in this meta-analysis. A pooled estimate showed vitamin E (OR: 0.75; 95% CI: 0.58, 0.96), α-carotene (OR: 0.72; 95% CI: 0.59, 0.88), lutein (OR: 0.75; 95% CI: 0.65, 0.87), and zeaxanthin (OR: 0.70; 95% CI: 0.60, 0.82) were inversely associated with age-related cataract. Vitamins A (OR: 0.69; 95% CI: 0.58, 0.83) and C (OR: 0.67; 95% CI: 0.57, 0.78) were inversely associated with age-related cataract in Asian populations but not in Western populations. β-Carotene (OR: 0.90; 95% CI: 0.78, 1.05), lycopene (OR: 0.86; 95% CI: 0.65, 1.15), and β-cryptoxanthin (OR: 0.83; 95% CI: 0.68, 1.02) had no significant association with risk of cataract.
  
  
  CONCLUSIONS
  This meta-analysis provides additional evidence supporting the view that blood levels of certain antioxidants are inversely associated with risk of age-related cataract. However, the role of antioxidant or vitamin supplement intake in preventing cataract should be further investigated in interventional studies.
authors.affiliation: Department of Histology and Embryology, School of Basic Sciences, Guangzhou Medical University, Guangzhou, China.
authors.forename: Yu-Hong
authors.initials: YH
authors.lastname: Cui
authors.forename: Chun-Xia
authors.initials: CX
authors.lastname: Jing
authors.forename: Hong-Wei
authors.initials: HW
authors.lastname: Pan
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D044466:Asian People; D002338:Carotenoids / Q000097:blood*; D002386:Cataract / Q000097:blood / Q000209:etiology / Q000517:prevention & control; D006801:Humans; D014975:Lutein / Q000097:blood; D012307:Risk Factors; D014801:Vitamin A / Q000097:blood*; D014810:Vitamin E / Q000097:blood*; D014815:Vitamins / Q000097:blood*; D024341:Xanthophylls / Q000097:blood; D065146:Zeaxanthins
chemical_list: D000975:Antioxidants; D014815:Vitamins; D024341:Xanthophylls; D065146:Zeaxanthins; D014801:Vitamin A; D014810:Vitamin E; D002338:Carotenoids; C041635:alpha-carotene; D014975:Lutein