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People who have high blood pressure in their 40s seem to have smaller brains by the time they are 70. The findings provide more evidence that looking after your health can help prevent dementia, says Jonathan Schott at University College London, who led the study.
Around 30 per cent of dementia cases are thought to be preventable, says Schott. To find out how important blood pressure might be, his team turned to a group of individuals who have been part of a research project since they were born in 1946.
The volunteers had their blood pressure measured in their 30s, 40s, 50s and 60s. In the latest study, Schott’s team took brain scans and assessed the cognition of 502 members of the group, who were by that time aged between 69 and 71.
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The team found that people who had a higher diastolic blood pressure aged 43 were more likely to have smaller brains by the time they were around 70. A brain region vital for memory, called the hippocampus, seemed especially affected – individuals with a greater increase in systolic blood pressure between the ages of 36 and 43 had smaller hippocampi around 70. “It looks like one’s blood pressure is influencing one’s brain health 40 years later,” says Schott.
Because the results only show a correlation, the team can’t say for sure that high blood pressure was responsible for brain shrinkage. But we do know that high blood pressure is bad for the brain, and can lead to blood vessel damage. Without a healthy blood supply, brain tissue can die.
High blood pressure has been linked to dementia before. One study has found that people taking medication to lower their blood pressure are less likely to develop dementia. And vascular dementia, which is caused by a reduced blood flow to the brain, is the second most common cause of dementia.
The team didn’t find a link between blood pressure and brain plaques associated with Alzheimer’s disease or cognition. Schott thinks that is because the volunteers are still “relatively young”. Individuals with more brain shrinkage are more likely to show a faster rate of cognitive decline in the next 5 or 10 years, he says.
The findings highlight the importance of blood pressure in brain health. “Millions of individuals have unhealthy blood pressure,” Lenore Launer of the US National Institutes of Health writes in a comment on the study. “Immediate attention should be given to efforts to control blood pressure through clinical services and public health interventions.”
The UK’s National Health Service offers routine health checks, which include measuring blood pressure, for everyone once they reach 40. However, just under half of people invited for a check-up accept the invitation. “If you’re offered an appointment, you should take it up, and if you’re not, you should seek it out,” he says.
There are other things you can do to lower your chances of getting dementia. Keeping an eye on your weight, cholesterol and diet and making sure you have plenty of exercise and social interactions are all important.
Journal reference: The Lancet Neurology, DOI: 10.1016/S1474-4422(19)30228-5
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