Study Explains How High Blood Pressure in Middle Age Affects Memory in Old Age
High blood pressure in middle age plays a critical role in whether blood pressure in old age may affect memory and thinking, according to a study published in the online edition of the journal Neurology.
“Our findings bring new insight into the relationship between a history of high blood pressure, blood pressure in old age, the effects of blood pressure on brain structure, and memory and thinking,” said study author Lenore J. Launer, PhD, National Institute on Aging, part of the National Institutes of Health (NIH), Bethesda, Maryland.
For the study, 4,057 older participants free of dementia had their blood pressure measured in middle-age (mean age, 50 years). In late life (mean age, 76 years) their blood pressure was re-measured and participants underwent magnetic resonance imaging (MRI) scans that looked at structure and damage to the small vessels in the brain. They also took tests that measured their memory and thinking ability.
The study found that the association of blood pressure in old age to brain measures depended on a history of blood pressure in middle age. Higher systolic and diastolic blood pressure was associated with increased risk of brain lesions and tiny brain bleeds. This was most noticeable in people without a history of high blood pressure in middle age. For example, people with no history of high blood pressure in middle age who had high diastolic blood pressure in old age were 50% more likely to have severe brain lesions than people with low diastolic blood pressure in old age.
However, in people with a history of high blood pressure in middle age, lower diastolic blood pressure in older age was associated with smaller total brain and gray matter volumes. This finding was reflected in memory and thinking performance measures as well. In people with high blood pressure in middle age, lower diastolic blood pressure was associated with 10% lower memory scores.
“Older people without a history of high blood pressure but who currently have high blood pressure are at an increased risk for brain lesions, suggesting that lowering of blood pressure in these participants might be beneficial,” said Dr. Launer. “On the other hand, older people with a history of high blood pressure but who currently have lower blood pressure might have more extensive organ damage and are at risk of brain shrinkage and memory and thinking problems.”
SOURCE: American Academy of Neurology
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