Blood pressure in midlife may be related to dementia risk

Washington: A recent study suggests that abnormal blood pressure in midlife persisting into late life increases the likelihood of developing dementia. "Our results suggest that one's blood pressure during midlife may influence how blood pressure later in life relates to dementia risk. We found that individuals 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," said Keenan Walker, Ph.D., assistant professor of neurology at the Johns Hopkins University School of Medicine.

In the study published in the journal of JAMA, researchers found that those people with the high blood pressure condition hypertension during middle age and during late life were 49 per cent more likely to develop dementia than those with normal blood pressure at both times.

But, 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 per cent. High blood pressure was considered any measurement more than 140/90 millimetres of mercury, whereas low blood pressure was defined as less than 90/60 millimetres of mercury. A cognitive exam, caregiver reports, hospitalisation discharge codes, and death certificates were used to classify participant brain function and determine cognitive impairment.

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. Walker said 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.