Higher blood pressure at night may increase Alzheimer's disease risk

Higher blood pressure at night more than in daytime may be a risk factor for Alzheimer's

disease in older men, suggest a new study from researchers at Uppsala University. Higher BP
at night than in daytime may increase Alzheimer's disease risk.

The study has now been published in the journal Hypertension.

‘Dementia’ is an umbrella term used to describe a category of symptoms marked by
behavioural changes and gradually declining cognitive and social abilities. Numerous factors,
including hypertension (high blood pressure), affect the risk of developing these symptoms.
Under healthy conditions, blood pressure (BP) varies over 24 hours, with lowest values
reached at night. Doctors call this nocturnal blood pressure fall 'dipping'.

However, in some people, this BP pattern is reversed: their nocturnal BP is higher than in

daytime. This blood pressure profile is known as 'reverse dipping'.

“The night is a critical period for brain health. For example, in animals, it has previously been

shown that the brain clears out waste products during sleep, and that this clearance is
compromised by abnormal blood pressure patterns. Since the night also represents a critical
time window for human brain health, we examined whether too high blood pressure at night,
as seen in reverse dipping, is associated with a higher dementia risk in older men," said
Christian Benedict, Associate Professor at Uppsala University's Department of Neuroscience,
and senior author of the study.

To test this hypothesis, the researchers used observational data from one thousand Swedish

older men, who were followed for a maximum of 24 years. The included men were in their
early seventies at the beginning of the study.

“The risk of getting a dementia diagnosis was 1.64 times higher among men with reverse

dipping compared to those with normal dipping. Reverse dipping mainly increased the risk of
Alzheimer's disease, the most common form of dementia," said Xiao Tan, postdoctoral fellow
from the same department and first author of this research.

“Our cohort consisted only of older men. Thus, our results need to be replicated in older

women," said Benedict.

According to the researchers, an interesting next step would be to investigate whether the

intake of antihypertensive (BP-lowering) drugs at night can reduce older men's risk of developing
Alzheimer's disease.

http://www.tribuneindia.com/news/health/higher-blood-pressure-at-night-may-increasealzheimers-disease-risk-209656