Lower blood pressure, better memory - study

Aggressively lowering blood pressure significantly reduced the risk of mild cognitive impairment and dementia among hypertension patients, US researchers said on Wednesday.

The results of a in a large government-backed clinical trial, presented at the Alzheimer's Association International Conference in Chicago, offer some of the first tangible steps individuals can take to reduce their risk for dementia, experts said.

The results come from a landmark 2015 trial involving more than 9 300 hypertension patients which showed significant cardiovascular benefits in people whose systolic blood pressure - the top number in a blood pressure reading - was lowered aggressively to below 120, compared to a higher target of under 140.

The study looked specifically at the implications of aggressive blood pressure lowering on symptoms of dementia from any cause, and mild cognitive impairment (MCI), a precursor to dementia.

It found that people whose blood pressure was lowered to below 120 had a 19 percent lower rate of new cases of mild cognitive impairment and a 15 percent reduction in MCI and dementia combined.

The takeaway of the study, said Dr Keith Fargo, director of scientific and outreach programs at the Alzheimer's Association, is "see your doctor and know your numbers", and in case of hypertension, to get it treated.

"Not only do we already know that [lowering blood pressure] reduces the risk for death due to stroke and heart attacks but we now know it supports healthy brain aging," he said in an interview.

Although the study showed effects on MCI and combined dementia plus MCI, it did not show an overall reduction in dementia alone, at least not yet.

Fargo said it takes longer for people to develop dementia, but as the study continues, he expects more people treated to the higher target of 140 will develop dementia. 

The study looked at all causes of dementia, including Alzheimer's, the most common form marked by clumps of amyloid in the brain, and vascular dementia, which is caused by blocked blood flow to the brain.

Fargo said the result most likely affects the impact of blood pressure lowering on vascular dementia but noted that many people with Alzheimer's also have some degree of vascular disease, and reducing the total dementia risk could delay the onset of memory problems.