DALLAS, Dec. 1 Researchers may have identified a new marker to spot individuals at risk of a first stroke, according to a study reported in the December issue of Stroke: Journal of the American Heart Association.
The substance, proinsulin, turns into insulin under the right conditions. Insulin is a hormone that helps the body use glucose and other energy sources. In this Swedish study, non-diabetic people with high levels of proinsulin had a sharply increased risk of first-time stroke especially women.
"High proinsulin concentration more than tripled the overall risk for first-ever stroke after adjusting for such risk factors as total cholesterol, high blood pressure, smoking, body mass index and insulin levels. And the risk for women was even more pronounced, says Bernt Lindahl, M.D., Ph.D., medical director of the Behavioral Medicine Clinic in the department of public health and clinical medicine, University Hospital of Northern Sweden.
The study found that non-diabetic men with the highest levels of proinsulin have more than a two-fold higher risk of stroke compared to men with the lowest levels. But for non-diabetic women the risk among those with the highest proinsulin levels is more than four times greater than for women with the lowest levels.
In women with both the highest diastolic blood pressure (the lower number in a blood pressure reading that represents the pressure between heart beats) and the highest levels of proinsulin, the risk of stroke jumps to nearly 20 times that of women in the studys lowest groups in both these categories, Lindahl adds.
"In the study, the diastolic blood pressure seems to be a stronger risk factor than the systolic blood pressure the higher number that represents the pressure during the heartbeat, he says.
Lindahl describes proinsulin as a "not fully matured form of insulin, a chemical substance produced by the pancreas to control the amount of sugar in the blood.