Scientists from the National Institutes of Health found that high and low blood pressure levels among different older age groups were linked to varying dementia risks.
They found that high systolic blood pressure in people more than 60 years old decreases the risk of dementia, but both lower and higher blood pressure is linked to decreased dementia risk in people older than 75.
Although midlife hypertension is associated with an increased risk for dementia, this risk in older people has not been well researched.
Previous studies have reported a U-shaped association between blood pressure and dementia risk, where both high and low blood pressure is linked to increased risk; however, the evidence for this association is limited.
In the current study, the team collected blood pressure, the onset of dementia, and mortality data from seven population-based cohort studies, including the NIA-funded Adult Changes in Thought (ACT) study.
They examined data on more than 17,000 participants from these cohorts and divided the participants into different age groups.
They found that higher blood pressure was linked to lower dementia risk for age groups (60 to 70 years old).
The U-shaped association where high and low blood pressures were linked to decreased dementia risk for the older age groups (75 years and older).
Interestingly, these associations for decreased dementia risk were not attributable to longer survival with lower blood pressure.
This study provides new evidence about how blood pressure affects dementia risk in older people, which previously has not been clearly defined.
The researchers note that these observational study results contradict evidence from randomized controlled trials that suggested controlling high blood pressure can reduce dementia risk.
The novel association in this study may be because their cohorts consist of a broader, older population rather than a specific subgroup of older people with high blood pressure and other cardiovascular risk factors.
If you care about dementia risk, please read studies about health issues that may double dementia risk, and how to use a healthy lifestyle to prevent dementia.
For more information about brain health, please see recent studies about drinking too much coffee linked to higher dementia risk, and results showing this supplement could keep dementia at bay.
The study was conducted by van Dalen JW et al. and published in JAMA Internal Medicine.
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