Controlling high blood pressure can reduce the risk of mild cognitive impairment and may also reduce the risk of dementia, according to a new study.
The systolic blood pressure intervention trial (SPRINT) study, published this week in the Journal of the American Medical Association, involved more than 9,000 people aged 50 or older who had hypertension but who did not have also have diabetes or a history of stroke.
The study found that lowering systolic blood pressure (the top number in a blood pressure reading) to less than 120 reduced the risk of new cases of mild cognitive impairment by 19%, compared to only reducing that top pressure reading to 140.
“One in five individuals [studied] did not get mild cognitive impairment, which is a gateway to dementia. Everyone with dementia has to cross through that mild cognitive impairment stage,” says Maria Carrillo, chief science officer for the Alzheimer’s Association. “When you prevent mild cognitive impairment, you prevent new cases of dementia.”
The study did not show a clear reduction in the risk of dementia. Fewer participants developed dementia in the group that received intensive treatment for hypertension vs. those who received standard measures, but the numbers weren’t large enough to be statistically significant.
But there might be a good reason for the somewhat murky results. The positive effects of more intensive treatment to lower blood pressure on participants’ overall heart health were so compelling that the study ended early so all participants could benefit from lowering their blood pressure more aggressively.
“I think the trial needed a few more years,” Carrillo says, in terms of getting a clearer picture of the link between blood pressure and dementia. That’s because dementia takes longer to develop than its precursor, mild cognitive impairment.
Additional research will begin as soon as early this year, with two years of additional follow-up and assessment of the study’s original participants. Researchers hope to publish results in 2023.
Carrillo says that people affected by or worried about dementia should talk to their health care practitioner about whether it might be safe and appropriate for them to get treatment or take more aggressive steps to lower their blood pressure. Current guidelines call for treating blood pressure when the top number in a reading hits 130 or higher; until 2017, the guidelines called for a diagnosis of high blood pressure at a reading of 140/90 for people younger than 65 and 150/80 for those 65 and older.