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The question

Why some people develop dementia and others do not often remains unclear. Might blood pressure play a role in this?

This study

The researchers analyzed data on 5,646 adults, including blood pressure readings taken when most were in their early 30s and again in their mid-40s. In a 15-year span after the participants were, on average, about 60 years old, 532 people were diagnosed with dementia. No correlation was found between early-30s high blood pressure and later-in-life dementia. However, women who had high blood pressure in their 40s were 65 percent more likely to develop dementia than were those who had normal blood pressure at that age. The risk was even higher — 73 percent — for women who developed high blood pressure for the first time in their 40s, compared with those whose blood pressure was normal in both their 30s and 40s. For men, no link was found between hypertension in either decade and subsequent development of dementia.

Who may be affected?

Women who have high blood pressure in their 40s. High blood pressure can damage small blood vessels in the brain, and previous studies have found uncontrolled high blood pressure late in life to be a contributor to dementia. A loss of memory and thinking skills, affecting behavior and making normal daily activities difficult, are characteristics of dementia, which affects more women than men. Alzheimer's is the most common form of dementia.

Caveats

The study found an association between midlife high blood pressure and development of dementia but not absolute proof that one caused the other. Among study participants, more men than women died, which the researchers said may have led to an underestimation of blood pressure's link to dementia in men.

Find this study

Online Oct. 4 in Neurology (neurology.org; click on "Ahead of Print")

Learn more

Information on dementia is available at ninds.nih.gov (search for "dementia: hope"). Learn more about blood pressure at heart.org (click "conditions").

The research described in Quick Study comes from credible, peer-reviewed journals.