October 4, 2017

expert reaction to study looking at high blood pressure in middle age and risk of dementia

Published in Neurology scientists report that women who develop high blood pressure in their 40s may be more likely to develop dementia years later.

Dr Rosa Sancho, Head of Research, Alzheimer’s Research UK said:

“We know that high blood pressure can be a risk factor for dementia but it is important to find out more about who this can impact and at what point in life.

“This work suggests that sex differences in the timing of dementia risk factors may have important implications for brain health.  We need to understand more about the possible sex-specific mechanisms through which elevated blood pressure affects dementia risk and if there is any difference between different forms of dementia.

“We need to be careful not to generalise the results to today’s population, as the effectiveness and availability of drugs for high blood-pressure have changed dramatically since the study started.

“The methods the study used have their limitations and this might have contributed to the absence of a link between blood pressure and dementia risk in men.  Fewer men were included in the study due to death during the follow-up period, which could have accounted for the differences seen between men and women.

“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.  Anyone who is concerned about their blood pressure levels should consult their GP.

“Alzheimer’s Research UK are currently funding a team of researchers at the University of Bristol to investigate the link between high blood pressure and dementia.  This work has the potential to identify stages where we could intervene most effectively to limit the damage of high blood pressure on the brain.”

Dr Doug Brown, Director of Research, Alzheimer’s Society, said:

“It is a well-established fact that high blood pressure in mid-life can increase our chances of developing dementia in later life.  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.

“The younger age of people involved in this study compared to previous ones may partly explain the difference, but as this new research goes against the grain we need to see more studies to fully understand possible sex differences in blood pressure and dementia risk.

“We should be mindful that this study tested the blood pressure of people in a particular health-scheme in Northern California in the 1960s and 70s.  Since then there have been advances in how blood pressure is treated – so it’s not clear how relevant the findings of this study are to the present UK population.

“The Lancet Commission on dementia suggested there is good evidence that treatment of hypertension reduces the chances of developing the condition.  We also know that keeping in good health may help reduce your risk of dementia and the NHS recommends that people over 40 should have blood pressure tested every five years with their GP or pharmacy.”

Prof. John Hardy, Professor of Neuroscience, UCL, said:

“This is a very interesting study which ties midlife high blood pressure with dementia risk.  This work is consistent with the observations of a 20% decline in the incidence of dementia over the last two decades (more people are getting dementia, because there are more old people, but the proportion of cases is going down).  This decline coincides with the aggressive control of cardiac risk factors over this period (blood pressure and cholesterol management, and smoking cessation).

“Note that this relates to midlife blood pressure.  Trials of drugs designed to reduce blood pressure in people with dementia have not been successful.

“This work is consistent with work suggesting blood vessel damage in midlife is a risk factor for later development of disease.  It’s difficult to make firm conclusions about differences between women and men with this kind of study.”

* ‘Female sex, early-onset hypertension, and risk of dementia’ by Paola Gilsanz et al. published in Neurology on Wednesday 4 October 2017.

Declared interests

None received.