High blood pressure linked to lower dementia risk in over 90s

17 January 2017

Alzheimer’s and Dementia: Age of onset of hypertension and risk of dementia in the oldest-old: The 90+ Study

A new study by researchers in the US suggests that developing high blood pressure after the age of 80 may be linked to a lower risk of dementia in those living beyond 90. The research is published today (Tuesday 17 January) in the journal Alzheimer’s and Dementia.

High blood pressure, or hypertension, affects around 16 million people in the UK and has previously been linked to an increased risk of dementia. Most of the evidence for this link comes from research investigating the effect of high blood pressure in mid-life, and the authors of this study set out to investigate this association in later life.

Participants were part of the 90+ Study – an initiative looking at factors affecting health in people over the age of 90. A total of 559 volunteers were given six-monthly dementia assessments for an average of 2.3 years. The researchers found that those who reported having been first diagnosed with high blood pressure between the ages of 80 and 89, were less likely to develop dementia than those who had never had high blood pressure. Those who developed high blood pressure even later (over 90 years old at first diagnosis) were the least likely to develop the condition. This study took into account the use of medication to lower blood pressure, which was not found to affect dementia risk.

Dr Laura Phipps, from Alzheimer’s Research UK, said:

“With an increasingly ageing population, it’s important that we understand more about the factors influencing dementia risk and how these might change as people get older. While the weight of current evidence points to high blood pressure in midlife increasing a person’s risk of dementia, this study suggests this might not hold true for the very oldest of us. This research is still in the early stages and the reasons why high blood pressure might be linked to lower dementia risk in later life still need exploring. High blood pressure may play a protective role in the brain in the very later stages of life, but the link could also be driven by a drop in blood pressure being an early sign of dementia in older people.

“There are many known health risks associated with high blood pressure, so people shouldn’t see these findings as a reason to abandon a healthy lifestyle or their current medication plan. Anyone with concerns about their vascular health should seek out the advice of their GP.

“As well as maintaining a healthy blood pressure, there are other steps people can take to help reduce their risk of dementia. The best existing evidence suggests that not smoking, only drinking in moderation, staying mentally and physically active, eating a balanced diet, and keeping cholesterol levels in check can all help to keep our brains healthy as we age.”