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| |  Is there a Link between Alzheimer's Disease and Macular Degeneration? Presented at ARVO By Cameron Johnston FT. LAUDERDALE, FL -- May 9, 2007 -- There appears to be an association between Alzheimer's disease and the onset of age-related macular degeneration (AMD), researchers have reported here at the meeting of the Association for Research in Vision and Ophthalmology (ARVO). According to the investigators, who are from the Center for Preventive Ophthalmology and Biostatistics at the University of Pennsylvania in Philadelphia, United States, the prevalence of AMD in Alzheimer disease patients living in nursing homes is more than double that among the general population. Agnieshka Baumritter, MA, a biostatistician with the centre, said prior studies have shown that there are similarities between the plaque that develops in the brains of Alzheimer's patients and the chemical beta-amyloid protein that is found in drusen -- the fatty deposits that weep through the retina in patients with macular degeneration. This suggests that the two diseases share some common pathogenic pathways. This cross-sectional pilot study involved analyzing current population data to determine what the expected rate of AMD and Alzheimer's should be, and then comparing the data to actual rates seen in one nursing home. Out of a total nursing home population of 194 patients, 59 with probable Alzheimer's consented (or their caregivers consented) to be tested for AMD. Of these, 51 had at least two gradable fundus photos taken so the investigators could study the retina for abnormalities. The mean age of the patients was 75 years, and 11% were non-Caucasian. For the purposes of the study, late AMD was defined as the presence of choroidal neovascularisation in one or both eyes, or the presence of geographic atrophy. Early stage AMD was defined as the presence of at least one large (>125 microns) drusen in one or both eyes. Late AMD was observed in 5 (10%) of the 51 Alzheimer's patients, which was almost twice what would be expected in the general population (2.6). This corresponds to a standardized ratio of 1.93, Baumritter said. Early stage AMD was present in 14 (30%) of the study group, while in the general population, one might expect to see this is 6.5 people. This represents a standardized ratio of 2.15. Baumritter cautioned that the low participation rate means the data is not as strong as she would like. However, it does suggest an association between the two conditions that warrants further study. Patients with Alzheimer's disease may not always be able to tell their caregivers if they have vision problems. And failing vision may make them more vulnerable to accidents such as falling. By the year 2020, the prevalence of both Alzheimer's and macular degeneration are expected to double as a result of the aging population, Baumritter says, and therefore, there is a pressing need to understand these two diseases, which currently affect more than six million people in the United States. Baumritter says that this was a pilot study and more research will be conducted. For example, full blood panels exist for these patients and they too will be examined to determine whether there are common elements between patients and their diseases. Genetic testing is probably farther down the road.
[Presentation Title: Prevalence of Age-Related Macular Degeneration Among Patients With Alzheimer's Disease. Abstract 2092 B701]
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