A prospective study of carotenoid and vitamin A intakes and risk of cataract extraction in US women

Abstract

Background: Oxidation of lens proteins plays a central role in the formation of age-related cataracts, suggesting that dietary antioxidants may play a role in prevention. However, the relation between specific antioxidants and risk of cataract remains uncertain. Objective: Our objective was to examine prospectively the association between carotenoid and vitamin A intakes and cataract extraction in women. Methods: A prospective cohort of registered female nurses aged 45–71 y and free of diagnosed cancer was followed; in 1980, 50461 were included and others were added as they became 45 y of age for a total of 77466. Information on nutrient intake was assessed by repeated administration of a food-frequency questionnaire during 12 y of follow-up. Results: During 761762 person-years of follow-up, 1471 cataracts were extracted. After age, smoking, and other potential cataract risk factors were controlled for, those with the highest intake of lutein and zeaxanthin had a 22% decreased risk of cataract extraction compared with those in the lowest quintile (relative risk: 0.78; 95% CI: 0.63, 0.95; P for trend = 0.04). Other carotenoids (α-carotene, β-carotene, lycopene, and β-cryptoxanthin), vitamin A, and retinol were not associated with cataract in multivariate analysis. Increasing frequency of intakes of spinach and kale, foods rich in lutein, was associated with a moderate decrease in risk of cataract. Conclusions: Lutein and zeaxanthin and foods rich in these carotenoids may decrease the risk of cataracts severe enough to require extraction.