Image: Wikimedia Commons Women who develop high blood pressure may have dementia

WOMEN who develop high blood pressure in middle age are significantly more likely to get dementia later in life, a major study has found.

The risk of dementia increased 73 percent among women who started having blood pressure problems in their 40s.

The findings, based on a study of more than 7,200 people in the US, reinforces growing evidence lifestyle in middle age has a marked impact on health in retirement.

British public health experts are increasingly worried about a sedentary and overweight generation of over-40s and predict overwhelming numbers suffering heart disease, cancer, and diabetes as they reach old age.

Now the Kaiser Permanente research institute in California found unhealthy lifestyles – a major driver of high blood pressure – could also push up rates of dementia in the years to come. Crucially, however, this only applied to women.

High blood pressure – known by the medical term hypertension – affects one in three British adults. And because it has no symptoms until it is too late, only half even know they are at risk

The researchers, writing in the Neurology medical journal, said: ‘Although elevated blood pressure is more common among men than women in early and mid-adulthood, our results suggest that hypertension in mid-adulthood is a risk factor for dementia only for women.’

They believe high blood pressure may be more dangerous for women than men, and the impact might not be limited to dementia.

The study involved 7,238 people, tracked from the mid-1960s. They had their blood pressure checked at the beginning of the study, when the participants had an average age of 33, then again at an average age of 44.

The researchers monitored the group until 2011, in which time 532 people were diagnosed with dementia.

They found women who already had high blood pressure in their 30s were at 31 per cent increased risk of dementia, when compared to women with stable, normal blood pressure. But among those who developed it in their 40s, the increased risk soared to 73 per cent.

The results were the same when researchers adjusted for other factors that could affect the risk of dementia, such as smoking, diabetes, and body mass index.

Researcher Dr Rachel Whitmer said: ‘High blood pressure in midlife is a known risk factor for dementia, but these results may help us better understand when this association starts, how changes in blood pressure affect the risk of dementia and what the differences are between men and women. Even though high blood pressure was more common in men, there was no evidence that having high blood pressure in one’s 30s or 40s increased the risk of dementia for men.

‘More research is needed to identify the possible sex-specific pathways through which the elevated blood pressure accelerates brain aging.’

Blood pressure is expressed as two numbers, systolic, the upper number, and the lower diastolic. The research team defined high blood pressure as a systolic number 140, or a diastolic number of 90.

Dementia affects around 850,000 people in the UK, with the number set to rise to more than a million by 2025.

Dr Rosa Sancho, head of research at Alzheimer’s Research UK, said: ‘As a general rule of thumb, what is good for your heart is also good for your brain. 

‘As well as maintaining a healthy blood pressure, the best current evidence suggests that a healthy lifestyle including not smoking, 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.’

Dr Doug Brown, director of research at the Alzheimer’s Society, added: ‘Previous research has shown links between hypertension and dementia among both sexes, so this work suggesting a link in women but not men is surprising. As this new research goes against the grain we need to see more studies to fully understand possible sex differences.’

© Daily Mail