In a new study, researchers found that higher blood pressure at night than in daytime may be a risk factor for Alzheimer’s disease in older men.
The research was conducted by a team at Uppsala University.
Dementia is an umbrella term used to describe a category of symptoms marked by behavioral changes and gradually declining cognitive and social abilities.
Many factors, including hypertension (high blood pressure), affect the risk of developing these symptoms.
Under healthy conditions, blood pressure (BP) varies over 24 hours, with the lowest values reached 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 the daytime. This blood pressure profile is known as reverse dipping.
Previous studies have shown that 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, the team examined whether overly high blood pressure at night, as seen in reverse dipping, is linked to higher dementia risk in older men.
They used data from 1,000 older Swedish men, who were followed for a maximum of 24 years. The men were in their early seventies at the beginning of the study.
The team found 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.
According to the researchers, an interesting next step would be to examine whether the intake of antihypertensive (BP-lowering) drugs at night can reduce older men’s risk of developing Alzheimer’s disease.
One author of the study is Christian Benedict, Associate Professor.
The study is published in Hypertension.
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