January 2007

 

CATARACT/ IOL

 

Forestalling nuclear cataracts with Centrum use


by Maxine Lipner EyeWorld Senior Contributing Editor

 

 

Taking a multivitamin may help to keep some cataracts at bay

Example of progression of nuclear cataract at baseline and after 5 years from the age-related eye disease study (AREDS), with a change of 2 units in a nuclear opacity density scale.

A Centrum (Wyeth, Madison, N. J.) multivitamin once a day may keep nuclear cataracts away, according to the latest study results in a recent issue of Ophthalmology. The study, which involved a cohort of patients from the Age-Related Cataract and Eye Disease (AREDS) trial was an analysis of opportunity, said Roy C. Milton, Ph.D., senior biostatistician, EMMES Corporation, Rockville, Md. “It was not anything that was planned, but as we were recruiting people for AREDS, a study of several antioxidants at mega-dose levels, it was clear that many of the people who were coming into the study were already taking multivitamins of one sort or another,” Dr. Milton said. Investigators decided that patients could continue to take a multivitamin, but if they chose to do so were asked to take Centrum without lutein, in an attempt to standardize things.

Although the AREDS mega-dose study had shown no effect, investigators decided to take a retrospective look at the “Centrum effect” because of their ready-made population and based on the results of a previous study conducted in China that had shown a protective effect for a multivitamin supplement in that group of patients (Archives of Ophthalmology, September 1993).

AREDS Centrum sub-study

The AREDS study included approximately 4,757 patients. When investigators looked back retrospectively, they found that about two-thirds of the patients had been taking Centrum during the course of the study. “Our decision to take a look and see if we could tease out something about the possible effect really came after the trial had ended,” Dr. Milton said. “But the data was there and permitted us to take a look.”

This sub-study was certainly not a randomized one, Dr. Milton stressed. Because investigators used a statistical technique to adjust Centrum–use propensity scores and other co-variants, Dr. Milton dubbed the trial a “quasi-randomized one.”

Results from the trial were consistent with those originally seen in the Chinese study. “We saw that with the prevalence of any lens opacity, there was a reduction in the development or progression to that event with a statistically significant odds ratio of 0.84,” Dr. Milton said. “This suggests a modest effect.” Investigators also looked at individual lens opacity types. “We did see that the protective aspect of Centrum appeared to be mostly for nuclear opacity where the odds ratio was now 0.75, suggesting a somewhat stronger statistically significant effect,” he said.

Based upon these results, investigators concluded that progression of nuclear opacities may be delayed with daily Centrum use. “Multivitamins seem to be good for a lot of things and seem to have no downsides,” Dr. Milton said. “This raises the possibility that among its potential benefits, it could be beneficial in delaying the development of cataracts.”

However, Dr. Milton recognizes that since the study was not pro-spective or randomized, it doesn’t quite meet the gold standard. Results from a National Eye Institute randomized controlled trial on this, underway in Parma, Italy, will be available next year. “Our results are further evidence that this could delay cataract formation, but we really want to see what the Parma study will show us,” he said.

Clinical impact

Elizabeth A. Davis, M.D., adjunct assistant clinical professor, University of Minnesota, Minneapolis, sees the study as an interesting one. “The nice thing about this study is that it was long term, with a median follow-up of 6.3 years,” Dr. Davis said. “Also, they were able to use what was called a propensity score to eliminate any confounding factors.” She saw this method as trying to remove as much bias as possible.

“The study does suggest that taking a multivitamin supplement may be protective against nuclear cataract formation,” she said. The clinical impact will likely depend largely on whether these results are substantiated by the Parma study in 2007. “It will be interesting to see what that brings,” Dr. Davis said. “These are both two well-designed studies and if they have similar conclusions, that would really suggest that we should be recommending Centrum or a multivitamin to all of our patients.”

Dr. Davis thinks that learning more about the multivitamins that people take is a good thing. However, the study does bring to mind a question. “The question will come up at what age should somebody start to take these vitamins,” Dr. Davis said.

Study results have not been accepted by all. Richard S. Hoffman, M.D. clinical associate professor of ophthalmology, Casey Eye Institute, Oregon Health Sciences University, Portland, Ore., sees the analysis as a thorough one that strove to eliminate bias. However, he is skeptical of the results. “It’s really difficult for me to believe that there is a benefit in a population of patients who are not nutritionally challenged,” Dr. Hoffman said. If mega-doses of antioxidants didn’t make a difference, why should Centrum, he wonders. “I’m not aware of the correlation of B vitamins and trace minerals being a risk factor for nuclear sclerotic cataract development,” he said.

Even if the results are subsequently proven by the Parma study, Dr. Hoffman isn’t convinced that practitioners should begin recommending multivitamins to patients for the purpose of forestalling cataract development. While 30 years ago cataract surgery was a lot more dangerous, today it is a lot more patient–friendly and not necessarily something to be avoided, Dr. Hoffman believes. For many patients it can be a doorway into the world of refractive surgery, he points out. “Cataracts are still a disease and you still like to prevent performing surgery, but more and more we’re using cataract surgery as a form of refractive surgery,” he said. “So, it’s not necessarily a bad thing to develop a cataract, especially if you had a refractive error to begin with.”

Overall, Dr. Davis is taking a wait–and–see approach. Multivitamins may be more valuable than first thought, she believes. “It seems like multivitamins aren’t just for pregnant women any more,” she said.

Editors’ note: Dr. Milton is an employee of the EMMES Corporation. Drs. Davis and Hoffman do not have any financial interests related to their comments.

Contact Information

Davis: 952-885-2467, eadavis@mneye.com

Hoffman: 541-687-2110, rshoffman@finemd.com

Milton: 301-251-1161, rmilton@emmes.com

Forestalling nuclear cataracts with Centrum use Forestalling nuclear cataracts with Centrum use
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