The new findings show for the first time that three risk factors--high density lipoprotein (HDL), low density lipoprotein (LDL), and smoking--affect the progression of atherosclerosis about equally in women and men, and in blacks and whites.
Results of the "Pathobiological Determinants of Atherosclerosis in Youth," or PDAY, study appear in January's issue of the Arteriosclerosis, Thrombosis and Vascular Biology journal.
"These results help settle a long-standing controversy," said NHLBI Director Dr. Claude Lenfant. "It was known that the buildup of cholesterol in arteries leads to heart disease but, because of the difficulty of gathering data on children, not when. PDAY is the first study of its kind to have the scale needed to give an answer. We now know that the risk factors important in adulthood are just as crucial in children."
"PDAY's results have profound implications for heart disease prevention," said Dr. Henry McGill, Senior Scientist at the Southwest Foundation for Biomedical Research and lead author of the article. "It was thought that, since heart disease deaths tend to occur 10 years later in women than men, women did not need to start preventive measures as early. These data confirm that all persons--women and men, black and white--need to adopt healthful habits as soon as possible."
In atherosclerosis, cholesterol is deposited in arteries. As more accumulates, the deposits thicken and obstruct blood flow and can rupture, leading to a blood clot and heart attack.
HDL helps remove cholesterol from arteries and a low level of it increases coronary heart disease (CHD) risk; LDL helps deposit cholesterol and a high level of it increases CHD risk. Smoking increases the risk of both CHD and aortic aneurysm, in which the main heart artery widens and can burst.
Earlier results from PDAY, begun in 1985, had indicated that atherosclerosis is a long process that begins early in life. The new findings draw upon much more data and extend the findings to young women.
PDAY involved 15 centers nationwide that gathered data from autopsies of 1,079 men and 364 women, ages 15-34, who died from accident, homicide, or suicide. Tissues and blood were analyzed at the Louisiana State University (LSU) Medical Center, under the direction of Dr. Jack P. Strong, Boyd Professor and head, Department of Pathology, LSU School of Medicine, New Orleans.
Measurements taken include blood levels of HDL and LDL, and thiocyanate, a chemical marker for smoking. Coronary arteries were examined for the extent of cholesterol deposits and scar tissue.
Results showed dramatic and early differences in atherosclerosis between those with good risk factor profiles and those with bad profiles. Those with high HDL levels, low LDL levels, and no evidence of smoking lacked severe deposits in arteries. By contrast, those with low HDL, high LDL, and smoking had marked fatty streaks and deposits. The differences between the subjects appeared by age 15.
Dr. Basil Rifkind, Senior Scientific Advisor, NHLBI Vascular Research Program, and Dr. Momtaz Wassef, Leader of the NHLBI Atherosclerosis Scientific Research Group, are available for comment. They can be contacted through the NHLBI Communications Office at (301) 496-4236.
Dr. McGill also is available for comment and can be contacted at the Southwest Foundation for Biomedical Research at (210) 670-3208.
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