Ongoing hypertension treatment important for dementia prevention

People over the age of 60 who are treated for their high blood pressure (hypertension) have a 26% lower risk of dementia compared to those who are untreated, according to research from UNSW Sydney’s Centre for Health Brain Ageing (CHeBA).

The study, published in JAMA Network Open, highlighted that dementia risk was substantially reduced in the treated hypertension group throughout late life. The study utilised data from 34,519 individuals across 15 different countries, including Australia, USA, Brazil, China, Italy, Central African Republic and Nigeria.

Medical doctor and lead author on the study Dr Matt Lennon said the findings were critical for general practitioners and family physicians, who are most commonly at the coalface of blood pressure management.

“We know that mid-life hypertension increases risk of all types of dementia by around 60%, and Alzheimer’s disease by 25%,” Lennon said.

“However, in late-life (ie, those older than 60) studies have variously found high blood pressure to increase, not affect or decrease dementia risk. This lack of clarity is deeply problematic,” Lennon said.

The research team clarified ambiguities in the field using big data from CHeBA’s COSMIC collaboration (Cohort Studies of Memory in an International Consortium). They aimed to understand how age, sex and race might change the association between blood pressure, antihypertensive use and dementia.

The study first identified that in late life people with unmedicated hypertension have a significantly elevated risk of dementia compared to those with medicated hypertension and healthy individuals. This relationship was not significantly altered by increasing age, which shows that even people in their 70s and 80s are at a lower risk of dementia if hypertension is treated.

It also illustrated that a single measure of blood pressure in late life was not associated with significant differences in dementia risk, with the authors suggesting that multiple measurements over time should be used to direct treatment.

Finally, the study indicated that there are no significant differences in the effect of blood pressure or antihypertensive use in different sexes or racial groups.

Co-Director of CHeBA and co-author on the research Professor Perminder Sachdev said, “The findings indicate that ongoing antihypertensive therapy throughout late life is an important part of dementia prevention.”

The findings will have an impact on blood pressure management guidelines and will change parts of the academic conversation around blood pressure, Lennon said.

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