Healthy Diet Linked to Lower Risk for Nuclear Cataract in Women
By Laurie Barclay, MD
Medscape Medical News
June 16, 2010 — Healthy diet is linked to a lower risk for nuclear cataract in women, according to the results of a large, prospective study reported in the in the June issue of Archives of Ophthalmology.
"The Carotenoids in Age-Related Eye Disease Study (CAREDS), an ancillary study of the Women's Health Initiative (WHI), was designed in part to evaluate the relationships of the carotenoids lutein and zeaxanthin with the prevalence of age-related nuclear cataract and age-related macular degeneration," write Julie A. Mares, PhD, from University of Wisconsin, Madison, and colleagues from CAREDS.
"We previously reported that high dietary and blood levels of lutein and zeaxanthin were associated with lowered risk for nuclear cataract in this cohort. There are limited studies published to date in which nutritional risk factors are evaluated concurrently with a comprehensive set of other lifestyle, ocular health, and physical risk factors."
The goal of the study was to determine the relationship between healthy diet scores and the prevalence of nuclear cataract 4 to 7 years later in a sample of WHI participants, aged 50 to 79 years and living in Iowa, Wisconsin, and Oregon. At baseline in 1994 to 1998, the researchers calculated scores on the 1995 Healthy Eating Index (HEI-1995), reflecting adherence to 1990 US dietary guidelines, using responses to food frequency questionnaires. Higher diet scores resulted from intakes at or above recommended levels for vegetables, fruits, grains, milk, meat (or beans, fish, or eggs) and below recommended levels for fat, saturated fat, cholesterol, and sodium.
From May 1, 2001, to January 31, 2004, a total of 1808 women participating in CARED were evaluated for nuclear cataract, based on slit-lamp photographs and self-reports of cataract extractions. Nuclear cataract in at least 1 eye occurred in 736 women (41%).
Of numerous risk factors studied, a high HEI-1995 score was the strongest modifiable predictor of low prevalence of nuclear cataract. For high vs low quintile for diet score, the multivariate-adjusted odds ratio was 0.63 (95% confidence interval, 0.43 - 0.91). Other modifiable risk factors for nuclear cataract were smoking and marked obesity, and nonmodifiable factors were brown eyes, myopia, and high pulse pressure. Prevalence of cataract was not affected by vitamin supplement use.
"These data add to the body of evidence suggesting that eating foods rich in a variety of vitamins and minerals may contribute to postponing the occurrence of the most common type of cataract in the United States," the study authors write.
Limitations of this study include relatively healthy women comprising the sample, evaluation of prevalence vs incidence of nuclear cataract, lack of measurement of lead exposure and some other risk factors, and some possible misclassification of nuclear cataract.
"Diet was the strongest risk factor related to reduced risk of nuclear cataract in this sample of postmenopausal women," the study authors conclude. "Smoking and obesity were also contributors. Lifestyle improvements that include healthy diets, smoking cessation, and avoiding obesity may substantively lower the need for and economic burden of cataract surgery in aging American women."
The National Institutes of Health and by Research to Prevent Blindness supported this study. The National Eye Institute provided funding for the CAREDS, and the National Heart, Lung and Blood Institute provided funding for the WHI program. One of the study authors has served as an advisory board consultant for Eyetech and as a speaker for Alcon resident surgery course.
