alpha-carotene and Cataract

Observational studies have been inconsistent regarding the association between blood antioxidants or vitamins and risk of age-related cataract.. 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.. 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.. 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.. 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.

Topics: Antioxidants; Asian People; Carotenoids; Cataract; Humans; Lutein; Risk Factors; Vitamin A; Vitamin E; Vitamins; Xanthophylls; Zeaxanthins

It is not known whether the protective effects of antioxidants on cataract observed in experimental animals are relevant to age-related opacities in humans.. The relations of serum carotenoids and tocopherols to the incidence of age-related nuclear cataract were investigated in a random sample of 400 adults, 50-86 y of age, in the Beaver Dam Eye Study.. Nuclear opacity was assessed by using lens photographs taken at baseline (in 1988-1990) and follow-up (in 1993-1995). Nonfasting concentrations of individual carotenoids and alpha- and gamma-tocopherol, were determined from serum obtained at baseline. A total of 252 persons were eligible for incident cataract, of whom 57 developed nuclear cataract in at least one eye. Results were adjusted for age, smoking, serum cholesterol, heavy drinking, adiposity, and, in the tocopherol models, dietary linoleic acid intake.. Only serum tocopherol (the sum of alpha- and gamma-tocopherol, in micromol/mmol cholesterol) was associated with cataract. For total serum tocopherol, persons in tertile 3 had a lower risk of cataract than persons in tertile 1 [odds ratio (OR): 0.4; 95% CI: 0.2, 0.9; P = 0.03 for linear trend]. Although serum carotenoids were not significantly associated with nuclear cataract, marginal inverse associations with lutein (OR: 0.3; 95% CI: 0.1, 1.2; P = 0.13 for linear trend) and cryptoxanthin (OR: 0.3; 95% CI: 0.1, 1.3; P = 0.11 for linear trend) were suggested in people < or = 65 y of age.. Findings were compatible with the possibility that nuclear cataract may be linked inversely to vitamin E status, but neither strongly supported nor negated the hypothesized inverse association of nuclear cataract with serum carotenoids.

Topics: Age Factors; Aged; Aged, 80 and over; beta Carotene; Carotenoids; Cataract; Cryptoxanthins; Female; Humans; Incidence; Lutein; Lycopene; Male; Middle Aged; Prospective Studies; Risk Factors; Vitamin E; Xanthophylls