Nocturnal high systolic blood pressure that is higher than daytime BP may be a risk factor for Alzheimer’s disease in older men. More research is needed, but these study results suggest that taking blood pressure medication at night may be advisable, according to researchers at Uppsala University, Sweden and published in the journal Hypertension.
It is known that numerous factors, including hypertension (high blood pressure), affect the risk of developing dementia symptoms, including behavioral changes and gradually declining cognitive and social abilities.
As you know, under healthy conditions, blood pressure (BP) varies over 24 hours, with lowest values reached at night, called ‘dipping.’ However, in some, this BP pattern is reversed with nocturnal BP higher than in daytime, 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,” says 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,” says Xiao Tan, postdoctoral fellow.
- Twenty-four-hour ambulatory BP monitoring was used to estimate the nocturnal systolic BP dipping status of men at mean age 71 (n=997; 35% on antihypertensive medication) and 77.6 (n=611; 41% on antihypertensive medication).
- Dementia incidence during the observational period up to 24 years (n=286 cases) was determined by reviewing participants’ medical history and independently confirmed by at least 2 experienced geriatricians.
According to the researchers, an interesting next step would be to investigate whether the intake of antihypertensive (BP-lowering) drugs at night can reduce nocturnal blood pressure in older men and reduce risk of developing Alzheimer’s disease. “Our cohort consisted only of older men. Thus, our results need to be replicated in older women,” concludes Benedict.
Conclusion/ The findings suggest that reverse systolic BP dipping may represent an independent risk factor for dementia and Alzheimer’s disease in older men. Future studies should decipher whether therapies lowering nocturnal systolic blood pressure below daytime levels, such as bedtime dosing of antihypertensive medication, can meaningfully curb the development of dementia.