Teenage blood pressure risk clue

High blood pressure is a risk factor for heart disease and stroke

Teenagers whose bodies do not process insulin properly have a higher risk of high blood pressure as adults, researchers suggest.

University of Minnesota scientists studied over 350 children with an average age of 13 for five years.

They suggest insulin resistance should be treated during teenage years to prevent later problems.

The scientists presented their findings to an American Heart Association meeting on blood pressure.

In insulin resistance, the body continues to produce insulin but the hormone does not work effectively. This means that the body cells cannot take up enough glucose.

This could mean the damage is being done before people develop diabetes and probably long before they are diagnosed Diabetes UK spokesman

The researchers monitored insulin resistance when the teenagers enrolled in the study, then again at the ages of 15 and 19.

They looked at systolic blood pressure - the top number in a blood pressure reading which measures the pressure in arteries when the heart contracts.

At age 13, none of the children had high blood pressure. But by age 19, systolic blood pressure had increased by 0.42 mm Hg (millimetres of mercury) for each unit of insulin resistance at age 13, and it increased by 0.81 mm Hg for each unit increase in their body mass index (BMI), which is measured by divide weight in kilograms by height in metres.

A BMI of between 20 and 25 is considered healthy.

But the effects of insulin resistance on systolic blood pressure were independent of those related to their BMI.

Insulin resistance was also linked to obesity, but statistical analysis showed that it was independently associated, to lesser extent, with unfavourable changes in cholesterol levels and other blood fats.

Independent effect

Alan Sinaiko, professor of paediatrics at the University of Minnesota who led the study, said: "The results indicate that one of the keys to preventing high blood pressure is to start thinking about it in childhood.

"If insulin resistance in childhood is related to risk factors in adulthood, we ought to be thinking about this problem at an early age. By the time people are in their 20s and 30s, a lot of the risk is already set, and we are treating the disease instead of preventing it."

He added: "We know that insulin resistance exists, but we don't know a lot about the insulin resistance syndrome and how it develops.

"This study shows that insulin resistance is present at a very young age. Even though children don't have the same degree of heart risk factors as adults, the findings suggest that insulin resistance has an early influence on what happens to people as adults."

Professor Sinaiko said: "There is no question that obesity in some people is significantly related to insulin resistance.

"What we're showing is that insulin resistance has an effect on systolic blood pressure that is independent of fatness and obesity.

"Strategies designed to reduce childhood obesity to prevent cardiovascular risk and Type 2 diabetes may need to be complemented by treatment of insulin resistance in at-risk people."

A spokesman for Diabetes UK said: "Insulin resistance and Type 2 diabetes are very closely linked. We already know that people with diabetes are at an increased risk of high blood pressure.

"If insulin resistance does increase the blood pressure risk independently, this could mean the damage is being done before people develop diabetes and probably long before they are diagnosed."