MULTIVITAMINS/VITAMIN E MAY REDUCE LENS OPACITY RISK
MULTIVITAMINS/VITAMIN E MAY REDUCE LENS OPACITY RISK with a risk reduction of one-third associated with multivitamin intake (relative risk - .69) and approximately one-half with vitamin E use (RR .43) and higher plasma levels of vitamin E (RR .58), according to results from research on participants in the Longitudinal Study of Cataract by Cristina Leske, MD, University Medical Center at Stony Brook (N.Y.), et A The observational study, published in the May issue of Ophthalmology, measured annual levels of nuclear opacity in 744 participants.
Increased severity of nuclear opacification - clouding of the ocular lens - is associated closely with the development of cataracts. Nuclear opacity is the most frequent type of opacity reported in cataract prevalence studies in the U.S. and Europe, the researchers note.
Of the 567 subjects who saw no increase in nuclear opacity, 26.1% (148) reported regular multivitamin use compared to 21% of the 177 subjects (37) who saw an increase in opacity in one or both eyes. Regular use of supplements was defined as at least once per week for a year.
In a much smaller group, 54 subjects (7.3%) reported using vitamin E. Those who used vitamin E for five years or more were four times less likely (RR .26) to see an increase in nuclear opacity than non-users. Those who used vitamin E for less than five years saw a one-fifth drop (RR .81) in their risk of increased nuclear opacification. Median vitamin E plasma concentration was 1.40 mg/dL in the group with no increase, compared to 1.33 in the group whose opacities became more severe.
"Because of the observational nature of the study and the possibility of biases, our results are suggestive, but not conclusive, and should be interpreted cautiously," Leske et al. say.
The researchers note they are awaiting results from ongoing clinical trials such as the National Eye Institute Age-Related Eye Disease Study. Storz Ophthalmic, recently acquired by Bausch & Lomb, markets the Ocuvite line of antioxidant ocular supplements and is providing support for the trial. Until the NEI studies are completed, Leske et al. "emphasize there is no firm evidence to support a recommendation to use nutritional supplements for cataract prevention."
In the Ophthalmology study, 764 patients were recruited from an earlier research effort, the Lens Opacities CaseControl Study. Eye exams and nutritional questionnaires began in September 1989 and continued annually for an average of more than four years. Eighty percent of the subjects completed three or more visits, and, in the end, 744 patients had data on nuclear opacity changes. NEI provided funding for the Leske et al. study.
At baseline, researchers measured lens opacification and collected food intake data on vitamins C, E, riboflavin and carotene, the test subjects’ use of vitamin supplements (multivitamins, C and E) and plasma levels of vitamin E. The researchers also collected information on potential confounding variables including age, gender, race, education, current smoking status and coexisting cortical and posterior subcapsular opacities. The median age of subjects in the trial was 65. Some 44.9% of the subjects were male; 86.6%, white; 47% began with nuclear opacities in at least one eye.
(as reported in FDC Reports, June 8, 1998)