|Chylack Jr, Leo|
Submitted to: Archives of Ophthalmology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/1/2000
Publication Date: 7/1/2001
Citation: Jacques, P.F., Chylack Jr, L.T., Hankinson, S.E., Khu, P.M., Rogers, G., Friend, J., Tung, W., Wolfe, J.K., Willett, W.C., Taylor, A. 2001. Long-term nutrient intake and early age-related nuclear lens opacities. Archives of Ophthalmology. 119(7):1009-19. Interpretive Summary: Cataract, opacification of the eye lens, develops later in life and is most likely the consequence of decades of accumulated damage. Studies suggest that much of this damage is a consequence of oxidation. These observations are corroborated by human studies, which indicate a possible role for nutritional antioxidants in prevention of cataract. However, there is still much uncertainty regarding the role of antioxidant nutrients in the development of cataract. Many earlier studies report associations between risk of cataract and vitamin E, vitamin C, or carotenoids, but they do not demonstrate consistent associations between intake or blood levels of any one nutrient. This lack of specificity may be a consequence of differences in study populations or methods. One of the potential limitations of many earlier studies is the use of a single measurement of antioxidant intake to characterize usual intake even though it is recognized that cataract develops over a period of many decades. The present study examines the relation between lens opacities and usual nutrient intake, which was calculated as the average intake from five food frequency questionnaires that were collected over a 13-15 year period. We observed that vitamin C, lutein and zeaxanthin intake, and duration of vitamin C supplement use were significantly associated with risk of lens opacities. These protective associations increased in strength up to approximately 250 mg/day for vitamin C and up to about 5.7 mg/day for combined intake of lutein and zeaxanthin. Prevalence of lens opacities was also significantly lower for women who used vitamin C supplements for 10 or more years relative to women who never used supplements.
Technical Abstract: To assess the relation between nutrient intake and age-related, nuclear lens opacities, 478 non-diabetic, Boston-area women aged 53 to 73 years without previously diagnosed cataracts were sampled from the Nurses' Health Study cohort. Usual nutrient intake was calculated as the average intake from five food frequency questionnaires that were collected over a 13-15 year period before the evaluation of lens opacities. Duration of vitamin supplement use was determined from seven questionnaires collected during this same time period. We defined nuclear opacities as nuclear opalescence grade >/=2.5 of the Lens Opacification Classification System III. Vitamin C and lutein/zeaxanthin intake and duration of vitamin C supplement were significantly associated with risk of nuclear opacities. The prevalence of nuclear opacities was significantly lower in the highest vitamin C intake quintile category (odds ratio (OR)= 0.31; 95% confidence interval (CI): 0.16-0.58) and the highest lutein/zeaxanthin intake quintile category (OR= 0.55; 95% CI: 0.31-0.98) relative to the lowest quintile categories for these nutrients. These protective associations increased in strength up to approximately 250 mg/day for vitamin C and up to about 5.7mg/day for lutein/zeaxanthin. Higher intakes provide limited additional benefit. Prevalence of nuclear opacities was also significantly lower for women who used vitamin C supplement for +/-10 years relative to women who never used vitamin C supplements (OR= 0.36; 95% CI: 0.18-0.72). Plasma vitamins C and E concentration were also inversely associated with prevalence of nuclear opacities. Our results support a role for nutritional antioxidants in the prevention of age-related nuclear lens opacities.