Cholesterol-lowering medications may have positive association with AMD prevention

Studies continue to show mixed results, but physicians think there’s a
connection to statins.

Could cholesterol-lowering medications such as statins help prevent age-related macular degeneration (AMD)?
Evidence from a study published in the March issue of Ophthalmology shows there’s some correlation.
“In this particular study, we found that statins seemed to lower the risk of AMD,” said Gerald McGwin Jr., M.S., Ph.D., Department of Ophthalmology, School of Medicine, University of Alabama, Birmingham.
Dr. McGwin has led two other studies on the topic, one published in the British Journal of Ophthalmology in 2003 that showed statin use was less common among individuals with AMD than those that did not have AMD. However, a third study slated for publication later this year found no correlation, said Dr. McGwin.
Although just how statins might reduce the risk for AMD development is unclear, the study said it may relate back to the medication’s lipid-lowering effect and the accumulation of lipids such as cholesterol in Bruch’s membrane and in drusen.
Statins are also shown to have ancillary properties such as improving or restoring endothelial function, according to the study.
Even if a connection is not yet certain, retina specialists agree the research taps an unexplored nerve.
“You’ve got half the articles saying there’s clearly a correlation and half saying there’s no association between the two,” said Jason S. Slakter, M.D., Vitreous-Retina-Macula Consultants of New York, New York. “I think there may be something there and we need to look at it.”
“Medications and dietary factors involving lipid metabolism seem to have some effect on preventing AMD,” said James Maisel, M.D., Hauppauge and Hicksville, N.Y.
“The current study involved younger individuals and may not strongly reflect the benefit of statins on AMD prevention that may be due to secondary anti-inflammatory effects of these medications.”

Study details

Dr. McGwin and co-authors used data from the Atherosclerosis Risk in Communities study, a population-based cohort study (15,972 participants) that took place in four communities across the U.S. between 1987 and 1989. The study was published in 1989 in the American Journal of Epidemiology.
By using fundus photographs from 12,588 participants, the investigators obtained during follow-up between 1993 and 1995, Dr. McGwin and co-authors were able to determine if participants had AMD. They also tracked whether participants had used cholesterol-lowering medications at any time during the study.
All study participants were between the ages of 45 and 64 years old.
Cholesterol medications other than statins, such as the use of cholestyramine, clofibrate, colestipol, and gemfibrozil, were also tracked.
Investigators also reviewed demographic data such as age, sex, and race, and health and behavioral-related factors such as cigarette smoking, alcohol consumption, body mass index, and chronic medical conditions.
Of the 12,588 study participants, 871 had AMD and 11,717 did not. Of the AMD cases, early AMD was seen in 94.7% of cases and late AMD in 2.6%.
Participants with AMD were more likely to be older (62 years old versus 59.8 years old), more likely to be male, and less likely to be black. There were no statistically significant differences between health factors.
Of the AMD cases, 11% used cholesterol-lowering medications versus 12.3% of the non-AMD participants. A statistical analysis showed that AMD participants were 20% less likely to use cholesterol-lowering medications than participants that did not have AMD.
“From the current evidence, it is difficult to dismiss the hypothesis that there is an association between the use of cholesterol-lowering medications and AMD,” the authors wrote.

Practical implications

The study can help researchers determine the etiology of AMD, said Dr. McGwin. It also contributes to the bodies of research on patients with AMD as well as the overall effect of cholesterol drugs — the numbers of which are both increasing as baby boomers age.
Dr. Slakter said specific information on cholesterol medication use, such as frequency, dosing, and prescription history, would have strengthened the study results.
He also wondered if patients on statins or other cholesterol-preventing medications follow healthier diets, thus controlling another factor that is thought to prevent or curtail the growth of AMD.
Dr. Maisel agreed.
“I would recommend anything that improves overall patient health that is neutral, or especially if beneficial, for AMD,” he said. “There are indications that the AREDS (Age-Related Eye Disease Study) vitamins may prolong life. These studies show that successful medications such as the statins are neutral or beneficial and merit further investigation.
“We are currently analyzing anonymous data from ZyDoc.com to study this,” he said.
He also encourages his patients to follow recommendations including a vitamin supplementation, along with a diet rich in fruits, vegetables, nuts and low in fat and to avoid smoking. “That’s what makes interpretations of one of these associations difficult to say,” said Dr. Slakter. “We need a prospective, randomized study of patients with AMD that controls for everything.”
Still, if patients say their primary-care doctors want them to take a statin medication, Dr. Slakter said it’s fine.
“At worst, it’s doing nothing [to prevent AMD] and it may be doing something to help,” he said.
Although the results are still tentative, Dr. McGwin draws a parallel to published observational research that correlates statin use to the prevention of Alzheimer’s disease.
“Someone will have to risk a clinical trial — and risk funding it,” to further investigate the ophthalmologic connection, said Dr. McGwin.

Editors’ note: Dr. Maisel is a clinical investigator, educator and consultant for Novartis (Basal, Switzerland). He also is a consultant for Eyetech Pharmaceuticals/Pfizer and chairman of ZyDoc.com. Dr. McGwin has no financial interests related to his comments.

Contact Information
Maisel: 516-939-6100, zydocmd@yahoo.com
McGwin: 205-325-8117, mcgwin@uab.edu
Slakter: 212-861-9797, jslakter@aol.com