Treating High Blood Pressure Reduces Dementia Risk

To Reduce Dementia Risk, Treat High Blood Pressure

By Liz Szabo edited by Allison Parshall

Treating high blood pressure for as little as four years can cut the risk of dementia by 15 percent, according to clinical a trial results published on Monday in Nature Medicine. In the investigation, intensive blood pressure reduction also lowered the risk of mild cognitive impairment, an early stage of memory loss in people who can still live independently, by 16 percent.

Although research has long linked hypertension and dementia, the new study provides the strongest evidence yet that taking medications for the former actually reduces someone’s risk of developing the latter.

“Our study shows that dementia is preventable,” says Jiang He, a physician who studies epidemiology, internal medicine and neurology at the University of Texas Southwestern Medical Center.

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The researchers studied nearly 34,000 people with high blood pressure in rural Chinese villages. The team randomly assigned half of the villages to an intensive hypertension reduction program, and people in the other villages received their normal care. After four years, 4.6 percent of those who underwent intensive blood pressure control—the goal of which was to lower their blood pressure to less than 130/80 millimeters of mercury (mm HG)—were diagnosed with dementia compared with 5.4 percent in the group that received standard care. Because doctors treated people for only four years, it’s not known if controlling blood pressure for a longer period of time would further reduce the dementia risk.

Those results provide “strong evidence” to support using antihypertensive medications to prevent dementia in people with high blood pressure, He said.

Beth Abramson, who studies cardiac disease prevention and women’s health at the University of Toronto, calls the results encouraging. Many people ignore their hypertension or fail to take medications as directed, even though the condition can cause heart attacks and strokes, says Abramson, who is co-chair of the American College of Cardiology Hypertension Workgroup and was not involved in the new study.

In the U.S., 48 percent of adults have hypertension, defined as a blood pressure that is consistently at or above 130/80 mm HG.

The hope of preventing dementia may motivate some people to take their blood pressure more seriously, says Mitchell S. V. Elkind, chief clinical science officer at the American Heart Association, who also wasn’t involved in the new study. Surveys show dementia is one of the diseases that Americans fear most.

According to the World Health Organization, 57 million people worldwide had dementia in 2021. This number is expected to nearly double every 20 years, reaching 82 million in 2030 and 152 million in 2050, according to the nonprofit organization Alzheimer’s Disease International.

The new findings resemble those from separate clinical trial research published in January in Neurology. That study treated people with hypertension for 3.3 years and followed them for a median of seven years. The investigation focused on lowering systolic blood pressure, the first number in a blood pressure reading, in older adults. Of the 4,200 people in the study who underwent cognitive assessment, the group that who decreased systolic blood pressure to less than 120 mm HG had a reduced risk of mild cognitive impairment or probable dementia; these participants’ risk was lowered by 11 percent compared with people who decreased their systolic blood pressure to below 140 mm HG. The study didn’t find any difference in the risk of probable dementia alone—possibly because it was smaller than the new study in China, because dementia can take many years to develop or because the trial was stopped early thanks to its overwhelmingly positive results in preventing cardiovascular events.

Scientists don’t know exactly how hypertension might contribute to dementia, says David Reboussin, a professor of biostatistics and data science at the Wake Forest University School of Medicine and first author of the January Neurology study. But, he adds, “if there is anything going on with small vessels and their ability to get oxygen to the brain tissue, then brain tissue will suffer. It will atrophy and die.”