In a new study, researchers found that abnormal blood pressure in midlife persisting into late life increases the risk of developing dementia.
The research was conducted by a team from Johns Hopkins University School of Medicine.
The study lasted two and a half decades and looked at data from more than 4,700 participants.
Although not designed to show cause and effect, the study suggests that maintaining a healthy blood pressure throughout life may be one way to help reduce one’s risk of losing brain function.
In the study, high blood pressure was considered any measurement more than 140/90 millimeters of mercury, whereas low blood pressure was defined as less than 90/60 millimeters of mercury.
A cognitive exam, caregiver reports, hospitalization discharge codes, and death certificates were used to classify participant brain function and determine cognitive impairment.
The team found that those people with high blood pressure during middle age and during late life were 49% more likely to develop dementia than those with normal blood pressure at both times.
However, putting one at even greater risk was having hypertension in middle age and then having low blood pressure in late life, which increased one’s dementia risk by 62%.
The results suggest that one’s blood pressure during midlife may influence how blood pressure later in life relates to dementia risk.
People with high blood pressure in midlife may benefit from targeting their blood pressure to normal levels in later life, as having blood pressure that is too high or too low in late life may further increase dementia risk.
The team says high blood pressure can be genetic, but can also be the result of not enough exercise and poor diet.
As people age, the top blood pressure number (systolic) oftentimes increases while the bottom number (diastolic) can decrease due to structural changes in the blood vessels.
Dementia itself may lead to a lowering of blood pressure, as it may disrupt the brain’s autonomic nervous system.
Stiffening of the arteries from disease and physical frailty can also lead to low blood pressure in late life.
The lead author of the study is Keenan Walker, Ph.D., assistant professor of neurology at the Johns Hopkins University School of Medicine.
The study is published in JAMA.
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