December 19, 2012

Aspirin and AMD

Posted in: Research and Developments

by Dan Roberts
Updated 12/19/12

This is an attempt to shed some light on the issue of aspirin and macular degeneration.

In the spring of 2005, a large study introduced some interesting new information about aspirin. The study was done using 39,876 women over a 10-year period in order to clarify the suspected differences between men and women in the way that aspirin affects the system.

To translate and summarize the conclusions of the study, 100 mg of aspirin every other day . . .

  • lowers the risk of stroke in women, but not in men
  • reduces the risk of cardiovascular problems in men, but not in women, EXCEPT women age 65 and older. (Information about men was not derived from this study, but from 5 other studies referenced)
  • has a greater benefit for people who don’t smoke
  • increases the risk of gastrointestinal hemorrhages (i.e. gastrointestinal bleeding and peptic ulcer) in women age 65 and older

The authors conclude by saying, “…any decision about the use of aspirin in primary prevention … must ultimately be made after [consulting a] physician or health care provider, so that the net absolute benefits and risks for the individual patient can be ascertained.” Here is the study, for those who wish to learn more:

Ridker, P.M., et al. “Low-dose aspirin in the primary prevention of cardiovascular disease in women.” (The New England Journal of Medicine. Vol 352 (March 31) Pgs 1293-1304. 2005. Read the original paper.

An earlier study that shed light on aspirin use in connection with AMD concluded that “therapy with … aspirin is associated with decreased rates of CNV [choroidal neovascularization] among AMD patients.” That study is:

“Statin and aspirin therapy are associated with decreased rates of choroidal neovascularization among patients with age-related macular degeneration.” (Wilson HL, Schwartz DM, Bhatt HR, McCulloch CE, Duncan JL. Department of Ophthalmology, UCSF School of Medicine, San Francisco, CA 94143, USA.)

This connection is made, because AMD has been shown to have causes in common with cardiovascular disease. In other words, treat the cardiovascular problem with aspirin, and you might also be helping to prevent AMD. Here is that study:

“Do age-related macular degeneration and cardiovascular disease share common antecedents?” (KK Snow, JM Seddon – Ophthalmic Epidemiology, 1999 – taylorandfrancis.metapress.com)

Inflammation is now thought to be one of those commonalities, and we all know that aspirin is a good anti-inflammatory.

That having been said, here is a more recent conflicting study (Ref: AAO Annual Meeting: Abstract 1620, May 3, 2010) that suggests aspirin might actually be somehow associated with progression of the disease.

4691 patients 65 years and older were asked about their use of aspirin and about other possible risk factors for aging macula disorders. The results showed that odds ratios for all grades of early aging macula disorder rose with increasing aspirin intake frequency for subjects who reported daily use.

These researchers, therefore, concluded that frequent aspirin use seems to be harmful for aging macula disorder in older populations. Study leader Dr. Paulus de Jong said, however, that patients with cardiovascular disease should not stop taking aspirin. “But if they are taking it as a pain killer, there are other medications they can use.”

A 2012 report, “Long-term Use of Aspirin and Age-Related Macular Degeneration” by Barbara E. K. Klein, MD et al (JAMA. 2012;308(23):2469-2478. doi:10.1001/jama.2012.65406) concluded that “Among an adult cohort, aspirin use 5 years prior to observed incidence was not associated with incident early or late AMD. However, regular aspirin use 10 years prior was associated with a small but statistically significant increase in the risk of incident late and neovascular AMD.” These results were derived from a 14.8 year followup of subjects in the Beaver Dam Eye Study.

It was reported here in November 2012 that Emily Chew, M.D. (deputy director, Division of Epidemiology and Clinical Applications, National Eye Institute) reported to Retina 2012 that evidence suggests there is no major harmful effect of aspirin use by AMD patients. Furthermore, she supported the opinion that aspirin may actually offer significant protection from the development of the disease.

The findings of the recent research by Dr. Klein et al, however, suggest that the mechanisms underlying the association of aspirin with late AMD may be different from its blood thinning properties. It might even be found to enhance new blood vessel growth, since it has been found in lab studies to increase vascular density. Dr. Chew based her comments on the blood thinning issue, but the recent findings suggest there may be more to to consider.

Dr. Chew recommends that, in light of aspirin’s benefit to the cardiovascular system, the best course of action for AMD patients is to consult with their physicians and take aspirin when it is clinically indicated. Until the results of this new research are substantiated by more studies, that is still good advice.

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