SANTA FE, N.M., March 20 -- Sex-related differences in an enzyme that breaks down blood fats -- particularly "bad cholesterol" known as LDL -- may explain why men develop heart disease earlier than women, say scientists today at the American Heart Association's epidemiology and prevention conference.
"There are gender differences in the risk of coronary artery disease, the cause of heart attack. Pre-menopausal women have lower cholesterol levels and higher HDL levels (the good cholesterol) and lower heart disease rates than men," says the study's lead author, John E. Hokanson, Ph.D.
"We have observed in the past that there are higher levels of the enzyme hepatic lipase in men than in women. We asked the question, does hepatic lipase account for these lipid differences in men and women, and, if so, to what extent?" adds Hokanson, research scientist in the department of medicine at the University of Washington, Seattle.
Hokanson's research -- the first to focus on hepatic lipase and gender in heart disease -- could point to a new mechanism for increased risk for heart disease that characterizes men, when compared to women, before age 55. The research could suggest new ways to intervene to reduce that risk, he says.
In the study, scientists tested 25 men, 21 to 59 years old, and 39 pre-menopausal women, 21 to 51 years old. Both groups had normal cholesterol levels. Hepatic lipase activity was 53.4 percent higher in men than in women.
"The differences in the type of cholesterol we see in men and women appear to be related to hepatic lipase, and differences in this enzyme's activity may account for much of the difference in heart disease risk between men and pre-menopausal women," Hokanson says.
Researchers have in recent years been studying what they call the
atherogenic phenotype, also called LDL subclass pattern B, which is
characterized by predominantly small, dense LDL, low levels
Contact: Carole Bullock
American Heart Association