The raised blood pressure of hypertension causes structural damage to tissues throughout the body. In the brain it leads to disruption of the blood-brain barrier, and consequent passage of inflammatory molecules into the brain, as well as an increased pace of rupture of small blood vessels, creating tiny areas of permanent damage. This is a matter of damage accumulating over time. Higher blood pressure implies a faster pace of damage accumulation, while a longer period of raised blood pressure implies a larger amount of damage overall. Thus, as noted here, the duration of hypertension correlates with dementia risk and mortality, a result of the damage done by raised blood pressure.
Elevated blood pressure (BP) has been linked to impaired cognition and dementia in older adults. However, few studies have accounted for long-term cumulative BP exposure. The aim of this study was to test whether long-term cumulative BP was independently associated with subsequent cognitive decline, incident dementia, and all-cause mortality among cognitively healthy adults. This study used data from the HRS (Health and Retirement Study) and ELSA (English Longitudinal Study of Ageing). A total of 7,566 and 9,294 participants from ELSA and the HRS were included, with a median age of 62.0 years.
The median follow-up duration was 8.0 years. Elevated cumulative systolic BP and pulse pressure were independently associated with accelerated cognitive decline, elevated dementia risk, and all-cause mortality. In conclusion, long-term cumulative BP was associated with subsequent cognitive decline, dementia risk, and all-cause mortality in cognitively healthy adults aged ≥50 years. Efforts are required to control long-term systolic BP and pulse pressure and to maintain adequate diastolic BP.