High blood pressure in adolescence can be linked to atherosclerosis risk in middle age

A blood pressure as low as 120/80 mm Hg in adolescence can be linked to a higher risk of atherosclerosis in middle age, according to a study led from Linköping University, Sweden. The findings, published in the journal JAMA Cardiology, indicate that high blood pressure early in life plays an important role in the development of coronary artery disease.

"High blood pressure is the largest modifiable risk factor for cardiovascular disease, which in turn is the largest single cause of death globally," says Pontus Henriksson, senior associate professor of nutritional physiology, who led the study together with Karin Rådholm, senior associate professor of general medicine, both at Linköping University.

Efforts to prevent and treat high blood pressure, also called hypertension, are currently primarily focused on adult individuals. But a new Swedish study corroborates the idea that blood pressure can begin to impact health early in life.

In their study, the researchers used advanced CT scans, so-called CT coronary artery scans, to examine the coronary arteries supplying blood to the heart. These scans were performed on around 15,000 men aged 50 to 64 years in the large national population study SCAPIS. The method provides high-resolution images of the size of atherosclerosis plaques in the blood vessels, and what they contain, which affects how risky they are.

Just over 10,200 of these men had taken the military conscription tests when they were about 18 years old. At that time, taking these tests was mandatory in Sweden for men, which means that the data is representative of Swedish men of that age. The researchers examined whether there was a correlation between the blood pressure men had at the age of 18 and the health of their coronary arteries nearly 40 years later.

Blood pressure is the force that occurs when the blood is pressed against the walls of the vessels. When the heart pumps blood, the pressure is higher. This is known as systolic pressure or upper pressure. When the heart relaxes and fills with blood for the next heartbeat, the pressure is lower and is called diastolic pressure or lower pressure. Blood pressure measurements state both numbers, in millimetres of mercury, mm Hg. A blood pressure below 140/90 mm Hg is considered normal according to Swedish guidelines.

The most important thing we see is that those who had a systolic pressure of 140 or a diastolic pressure of 90 or more were at a clearly increased risk of coronary artery atherosclerosis later in life. But the risk increased already at 120/80 mm Hg."

Karin Rådholm, General Practitioner at Vårdcentralen Kärna, Region Östergötland

Some recent international recommendations have lowered the limit value for what counts as elevated blood pressure to 120/80 mm Hg. Lower limit values mean that more people are at risk than before.

In the present study, the researchers found that the higher the blood pressure at the time of the military conscription tests, the higher the risk of atherosclerosis in middle age, with an increased risk already at a blood pressure of 120/80 mm Hg. In their analyses, the researchers have taken into account other factors that affect the risk of cardiovascular disease.

"The study shows that the development of atherosclerosis begins early. The health care system needs to treat high blood pressure in young people more actively. The problem is that high blood pressure rarely causes symptoms. It's not something you can feel, so if you don't measure your blood pressure, you can have hypertension without knowing it," says Karin Rådholm.

Some of the factors increasing the risk of high blood pressure, such as overweight and poor fitness, are more common among young people today than when the study participants were young 40 years ago.

"In just one to two generations, the proportion of young people with obesity has increased significantly while fitness has decreased. So, these results are highly relevant for those who are young today," says Pontus Henriksson.

Since only men were included in the study, it is not possible to draw conclusions about women's risk for disease.

The study was funded by, among others, the Heart-Lung Foundation, the Knut and Alice Wallenberg Foundation, the Swedish Research Council, Vinnova and the Joanna Cocozza Foundation for Children's Medical Research.