Macular Degeneration Doubles Heart Attack and Stroke Risk

Age related macular degeneration (AMD) doubles the risk of dying from a heart attack or a stroke, according to a new study.

Researchers at the University of Sydney (Australia) analyzed over 3654 baseline participants aged 49 years or more between 1992 and 1994. Five years later, a follow up was performed on 2335 of these people, and after ten years, 1952 were examined again. History and physical examination provided data on possible risk factors, and the analysis included retinal photographs graded using the Wisconsin system. Deaths and cause of death were confirmed by data linkage with the Australian National Death Index. Risk ratios (RR) were estimated using Cox models.

The results showed that of the population under age 75 who participated in the study, early presentation of AMD predicted a doubling of cardiovascular mortality from heart attack or stroke within a decade. The late stage disease was associated with a five-fold increase in death from heart attack and ten time the risk of death from stroke. These associations were not present when persons older than 75 were included. The study was published in the February 28, 2008, issue of the British Journal of Ophthalmology.

"As there are some concerns that current treatments for AMD could elevate stroke risk, these results have extremely important implications for the treatment of this disease in the elderly,” concluded lead author Professor Paul Mitchell, M.D., and colleagues of the department of ophthalmology.

AMD is a degenerative condition of the macula, the central part of the retina, and is caused by hardening of the arteries in the retina, which deprives the sensitive retinal tissue of oxygen and nutrients that it needs to function and thrive. This can result in loss of central vision, which entails inability to see fine details, to read, or to recognize faces. Advanced AMD, which is responsible for profound vision loss, has two forms: dry and wet. Central geographic atrophy, the dry form of advanced AMD, results from atrophy to the retinal pigment epithelial layer below the retina, which causes vision loss through loss of photoreceptors (rods and cones) in the central part of the eye. Exudative AMD, the wet form of advanced AMD, causes vision loss due to abnormal blood vessel growth in the choriocapillaries, ultimately leading to blood and protein leakage below the macula, eventually causing irreversible damage to the photoreceptors and rapid vision loss if left untreated.


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