TAMPA, FLORIDA – Aggressive treatment to lower blood pressure in older people has been shown to reduce the risk of developing mild cognitive impairment, a risk factor for dementia, US researchers said on Monday.
Although the results of the Journal of the American Medical Association (JAMA) have found no significant impact on the likelihood of developing dementia, experts said the study offers a glimmer of hope as the world's population ages and dementia becomes a growing concern .
Dementia, including its most common form of Alzheimer's, is expected to affect 115 million people worldwide by 2050.
So far, the best scientific minds in the world have not found a way to reliably prevent, cure, or treat dementia.
But some research suggests that high blood pressure – which affects three-quarters of people over 75 – may be a modifiable risk factor.
For the Systolic Blood Pressure Intervention Trial (SPRINT), more than 9,300 people with 50 years of age or older with high blood pressure (systolic blood pressure between 130 and 180 mmHg) were randomized to receive different interventions.
Some received intensive blood pressure control, with medications that reached 120 mmHg.
Others targeted a more standardized treatment goal of less than 140 mmHg.
The patients were followed up for about five years and received a battery of cognitive tests.
In the intensive care group, 149 participants were considered to have probable dementia, compared to 176 participants in the standard treatment group.
In other words, intensive blood pressure control "did not significantly reduce the incidence of probable dementia," the study said.
However, the researchers were cautiously optimistic about a secondary finding that mild cognitive impairment occurred in far fewer participants in the intensive care group – 287 compared to 353 participants in the standard treatment group.
"This is the first trial, to our knowledge, to demonstrate an intervention that significantly reduces the occurrence of MCI, a well-established risk factor for dementia," the study said.
An accompanying editorial at JAMA by Kristine Yaffe of the University of California, San Francisco, also emphasized the possibility that more research could confirm the technique as an effective prevention strategy.
"For older adults, almost all concerned about the diagnosis of Alzheimer's and related dementia, SPRINT MIND offers great hope," she wrote.
"The study shows that among those with hypertension, intensive control of SBP can reduce the development of cognitive impairment."
She asked to study the approach along with other vascular health efforts such as physical activity and prevention.
Maria Carrillo, chief scientist of the Alzheimer's Association, who is funding a two-year extension of the study to investigate any effects on dementia, called the findings "the strongest evidence to date on reducing the risk of mild cognitive impairment through treatment.
"MCI is a known risk factor for dementia, and everyone who experiences dementia goes through MCI," added Carrillo.
"However, the outcome of the study on reducing the risk of dementia was not definitive," hence the need for more research, she said.