The research was part of the federally funded Systolic Blood Pressure Intervention Trial (SPRINT), a large-scale, long-term clinical study that also measured the effects of lower blood pressure on cardiovascular and kidney function.
The trial, which began in 2010, compared two strategies for maintaining blood pressure among 9,361 adults with an average age of around 68 with increased cardiovascular risk. One group received the standard care strategy at the time, targeting systolic blood pressure (the pressure on artery walls when the heart beats) to below 140 millimeters of mercury. The other group received the same medication, but in higher doses, with a target blood pressure of 120 mm or less.
Treatment was stopped in 2015, two years earlier than the planned end date, because of benefits in cardiovascular health that resulted last year in a revision of the standard care guidelines to below 130 mm. Researchers continued to monitor most participants until June 2018. The trial was funded by the National Institutes of Health.
In SPRINT-MIND, the brain portion of the study, researchers used memory tests to assess participants for probable dementia (inability to perform daily activities independently) and early memory loss. The group receiving the intensive approach had a 19 percent lower rate of new cases of MCI.
A subgroup was also assessed, through brain magnetic resonance imaging (MRI), for the white matter brain lesions that are associated with a higher risk of stroke, dementia and higher mortality. While both groups showed an increase in white matter lesions, the increase was significantly less in the intensive treatment group.
The findings, which are expected to be published later this year, could provide a relatively easy way to lower the rate of Alzheimer’s dementia, which in the United States is 10 percent of people 65 and older.
“For many years now, we’ve observed that people with lower blood pressure, even if it’s achieved through medication, have a lower risk for developing dementia,” said Jeff Williamson, professor of internal medicine and epidemiology and chief of geriatric medicine at Wake Forest School of Medicine in Winston-Salem, N.C., who presented the study. “Now, for the first time in history, we have something to say if you lower your blood pressure, you can lower your risk for mild cognitive impairment and dementia.”
The study comprised a diverse population, including 30 percent African American and more than 10 percent Hispanic participants, with a range of educational backgrounds.
The lower blood pressure group experienced some adverse reactions, including dehydration and overheating, but “these were tolerable compared to the benefits,” Williamson said, adding, “I have many patients who say, ‘I don’t fear death so much as I fear losing my memory.’ ”
The results correlate with recent data showing reductions in new cases of dementia in developed Western countries that have improved medication management, decreased smoking and promoted healthier lifestyles, said Maria Carrillo, chief science officer at the Alzheimer’s Association.
“To reduce new cases of MCI and dementia globally, we must do everything we can — as professionals and individuals — to reduce blood pressure to the levels indicated in this study, which we know is beneficial to cardiovascular risk,” she said.