New study results published online today in Alzheimerās & Dementia: The Journal of the Alzheimerās Association suggest that onset of high blood pressure later in life is associated with lower dementia risk after age 90, especially if hypertension is developed at age 80 or older.
heart health risk factors are generally thought to increase dementia risk. These new findings challenge this idea and add to scientistsā understanding of hypertension and dementia risk over a personās life course. Researchers at the University of California, Irvine and colleagues followed 559 people for an average of 2.8 years to investigate the relationship between dementia, age of hypertension onset, and blood pressure measurements. All participants are from an ongoing, long-term study of people age 90 and older known as The 90+ Study.At enrollment, participants did not have dementia, were 93 years old on average, and 69 percent female. They received dementia assessments every six months during the study period. During the follow-up period, 224 (40%) of the participants were diagnosed with dementia. The researchers found that study participants who reported hypertension onset at age 80 to 89 were 42 percent less likely to develop dementia after age 90 compared to those who reported no history of high blood pressure. Participants whose hypertension began at age 90 or older were at even lower riskā63 percent less likely to develop dementia.
These associations were statistically significant and independent of whether participants were taking medications to treat hypertension. āIn this first-of-its-kind study, we find that hypertension is not a risk factor for dementia in people age 90 or over, but is actually associated with reduced dementia risk,ā said first author Maria Corrada, M.S., Sc.D., Professor of Neurology and Epidemiology at the University of California, Irvine. āThis relationship had not yet been examined in groups of older people in their 80s or 90s, known as the āoldest old.āā The authors also measured study participantsā blood pressure at enrollment. Those in the hypertensive range at baseline were at lower risk for dementia compared to those with blood pressure in the normal range. While these results were not statistically significant, the researchers observed that dementia risk declined as hypertension severity increasedāa trend consistent with the idea that, in this age group, hypertension may protect the brain from insults that lead to dementia. āThese new findings suggest some risk factors for dementia may change over the course of our lives,ā said Maria Carrillo, Ph.D., Alzheimerās Association Chief Science Officer. āWe have seen similar results in past studies comparing body mass in older adults with dementia risk.ā
āAge of Onset of Hypertension and Risk of Dementia in the Oldest Old: The 90+ Studyā is available to subscribers of Alzheimerās & Dementia at www.alzheimersanddementia.com. Preliminary results of this study were first presented at the Alzheimerās Association International Conference (AAIC) in July 2014 in Copenhagen, Denmark.
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The Alzheimerās Association is the leading voluntary health organization in Alzheimerās care, support and research. Our mission is to eliminate Alzheimerās disease through the advancement of research, to provide and enhance care and support for all affected, and to reduce the risk of dementia through the promotion of brain health. Our vision is a world without Alzheimerās. For more information, visit the Alzheimerās Association at alz.org or call the 24/7 helpline at 800-272-3900.