Orthostatic Hypotension Increases the Risk of Alzheimer Disease

Alzheimer disease (AD) is more than twice as likely to develop in elderly persons with orthostatic hypotension (OH) as in those without OH, according to a new study presented at the Annual Meeting of the American Academy of Neurology.¹ “Orthostatic hypotension is often associated with dementia,” according to Helen Petrovitch, MD, a researcher at the Pacific Health Research Institute in Honolulu, Hawaii. “This led us to ask if it actually precedes dementia and indicates it is more likely.”

Dr Petrovitch and colleagues drew on data from a large, longitudinal health study, the Honolulu-Asia Aging Study, a long-term, prospective study of neurodegenerative disease, stroke, and aging in Japanese American men. Between 1991 and 1993, OH was assessed in more than 2000 men, aged 71 to 93, who were free of dementia, stroke, heart disease, and Parkinson disease. OH was found in 120 persons (5.3%). Over a 7-year follow-up period, AD developed in 131 men. After adjusting for differences in age and other variables, the investigators found that those who had OH at baseline were 1.8 times as likely to have AD during follow-up as those who did not have OH (P = .006).

“Evidence suggests that orthostatic hypotension is a risk factor for future clinical Alzheimer disease,” Dr Petrovitch said, although the increase in risk is not great enough that changes in counseling are warranted for patients with OH. At the moment, there are no data to suggest different treatment strategies for patients with AD based on the presence of OH.

However, she said, “this helps us understand the whole process. We now want to ask whether this is happening because the same processes that led to dementia are occurring earlier in the autonomic nervous system, to determine if that can help us to treat dementia better.” Alternatively, she said, it might be that another pathological process, such as heart disease, is causing OH, which may secondarily affect the brain and thus contribute to the development of AD.
 

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Reference

1. Petrovitch H, Abbott RD, Ross GW, et al. Late-life orthostatic hypotension and the incidence of clinical Alzheimer’s disease [P09.127]. Poster Presentation, April 30, 2009.