High blood pressure appears to predict the progression to dementia in older adults with impaired executive functions but not in those with memory dysfunction, according to a new report.

In light of evidence that hypertension is a major risk factor for vascular brain diseases and vascular cognitive impairment, researchers postulated that the cognitive domain of dysfunction may be a crucial factor in determining the link between hypertension and cognitive deterioration.

To test the hypothesis, doctors from Canada and Iran studied 990 older adults whose average age was 83 years who had cognitive impairment but no dementia.

Over a five-year follow-up period, dementia developed at approximately the same rate among participants with and without hypertension.

A similar pattern was observed among those with memory dysfunction alone and with both memory and executive dysfunction.

According to the researchers, executive function is defined as the ability to organise thoughts and make decisions.

However, among patients with executive dysfunction only, presence of hypertension was associated with an increased risk of developing dementia.

“This study may have profound implications for community dwellers with cognitive impairment, no dementia,” the study’s authors wrote.

“Worldwide, neurologic disorders are the most frequent cause of disability-adjusted life years; among these, cere-brovascular disease is the most common risk factor, and dementia is the second most common.

“There is no preventive or therapeutic intervention to mitigate this public health burden.”

The researchers added that their results showed that “the presence of hypertension predicts progression to dementia in a subgroup of about one-third of subjects with cognitive impairment, no dementia. Control of hypertension in this population could decrease by one-half the projected 50 per cent five-year rate of progression to dementia”.