A pregnant woman has her blood pressure measured by a hospital staff
A pregnant woman has her blood pressure measured by a paramedic after she and colleagues were evacuated following an earthquake in Mexico City April 18, 2014. The magnitude 7.2 quake was centred in the south-western state of Guerrero, close to the Pacific beach resort of Acapulco, the U.S. Geological Survey (USGS) said. Some residents of the capital ran outdoors in their pajamas after the quake. Electricity was cut off in parts of the city and some residents said paintings fell off the walls while small parts of masonry crumbled inside apartment buildings. REUTERS/Bernardo Montoya REUTERS/Bernardo Montoya

A new research has found that people whose blood pressure is on the higher end in their middle age are more likely to experience mental decline, which is a common precurson of dementia, in their old age.

According to the United States study, whose lead author is Dr. Rebecca F. Gottesman, people who in their 50s and 60s suffered from hypertension or even a slightly high blood pressure level called prehypertension, 20 years later had steeper mental decline.

The lead author from the neurology department at John Hopkins University School of Medicine in Maryland said that the results of the study strengthened the link which was previously known to experts. Other studies had showed that high blood pressure has a connection to increased risk of dementia and stroke.

She also noted that the amount of decline associated with hypertension is modest but the amount is equal to being 2.7 years older at the start in comparison to not having it at all. She explained that prehypertension, often not treated, was also associated with cognitive decline.

Dr. Gottesman and her team made use of data on mental performance and blood pressure from early 1990's for more than 13,000 adults between the ages of 48 and 67. Above 5,000 of these adults were alive and available for testing from 2011 to 2013.

The data was collected after one round of mental tests and blood pressure readings in 1990-92, another round which involved verbal, memory and math tests, once in 1996-98 and the other in 2011-2013. The participants were divided into three groups. Those who had a less than 120 millimetres and 80 millimetres of mercury in systolic and diastolic respectively, were said to have normal blood pressure.

Those with 139 millimetres systolic and 89 millimetres diastolic were said to have prehypertension and those who had any reading above that were considered to have high blood pressure.

Results in JAMA Neurology showed that those who had hypertension had a chance of dying double that of those who didn't suffer from it. Those who survived seemed to have 9.5 per cent decline in their mental performance in their last rounds of test in comparison to those with normal blood pressure.

Read more in Reuters Health.