Intensive blood pressure control has been shown for the first time to reduce the risk of mild cognitive impairment, according to findings from a large US trial.

The preliminary results of the SPRINT MIND trial provide the strongest evidence to date about reducing risk of mild cognitive impairment and dementia through treating hypertension.

The trial compared two strategies for managing hypertension – an intensive one with a systolic blood pressure goal of less than 120mmHg versus a standard care goal of less than 140mmHg. All major classes of anti-hypertensive agents were included in the study, said the researchers.

It involved 9,361 hypertensive older adults with increased cardiovascular risk but without diagnosed diabetes, dementia or stroke.

Participants, who were recruited in October 2010, had a mean age of 67.9 years (35.6% women) and 8,626 completed at least one follow-up cognitive assessment.

After one year, mean systolic blood pressure was 121.4mmHg in the intensive-treatment group and 136.2mmHg in the standard treatment group.

Treatment was stopped in August 2015 due to cardiovascular disease benefit after a median follow up of 3.26 years, but cognitive assessment continued until June 2018.

The researchers found a statistically significant 19% lower rate of new cases of mild cognitive impairment in the intensive blood pressure treatment group.

In addition, those who received intensive treatment had a 15% lower risk of developing mild cognitive impairment and dementia combined.

However, a significantly lower risk of dementia was not found in those who received intensive treatment – though there was a non-significant reduction in probable dementia.

The preliminary findings from the trial, which was funded by US government health agencies, were reported last week at the Alzheimer’s Association International Conference (AAIC) 2018 in Chicago.

Study author Professor Jeff Williamson, from Wake Forest School of Medicine in North Carolina, presented the findings at the conference on Wednesday.

He said: “This is the first randomised clinical trial to demonstrate a reduction in new cases of mild cognitive impairment alone and the combined risk of mild cognitive impairment plus all-cause dementia.”

Dr Maria Carrillo, chief science officer at the US Alzheimer’s Association, said:

“This study shows more conclusively than ever before that there are things you can do – especially regarding cardiovascular disease risk factors – to reduce your risk of mild cognitive impairment and dementia.”

Dr Doug Brown, chief policy and research officer at the UK’s Alzheimer’s Society, said: “We know stress is bad for us, and high blood-pressure has been linked to an increased risk of vascular dementia.

“This study, which looked at the effect of lowering blood pressure beyond standard treatment guidelines, found that such treatment did not significantly reduce a person’s chances of developing dementia,” he said.

“But, lowering blood pressure did reduce the risk of mild cognitive impairment, a condition where people have minor problems with their thinking,” noted Dr Brown.

“The jury is still out on how much various risk factors increase your risk of developing dementia, but this study supports that what’s good for the heart is good for the head,”

he said.

“We need more in-depth, long-term research to unpick this relationship with brain health and dementia specifically,” he added.