The relationship between atherosclerosis and coronary heart disease is complex. Long-term studies in adults have determined that the progression of atherosclerosis is related to the presence of specific risk factors that reinforce each other over time if not treated. Autopsy data from adults have also demonstrated a relationship between coronary artery disease and cardiovascular risk factors, including cigarette smoking and high cholesterol levels. Berenson and colleagues report the findings from the Bogalusa Heart Study, which examined the influence of multiple cardiovascular risk factors on the extent of atherosclerosis in young people.
The Bogalusa Heart Study followed patients (65 percent white and 35 percent black) from birth to 38 years of age. To date, the researchers have collected data on approximately 14,000 people. The authors examined autopsy data from 204 study participants who had died from various causes, mostly trauma, between 1978 and 1996. Before their deaths, information had been obtained on body mass index, cigarette smoking status, blood pressure, and total cholesterol, triglyceride, high-density lipoprotein (HDL) and low-density lipoprotein (LDL) cholesterol levels.
At autopsy, the coronary arteries and the aorta were sectioned longitudinally to permit evaluation of the extent of lipid deposition on the intimal surface, including the presence of fatty streaks and raised fibrous plaques. The lesions were examined and graded visually by three pathologists who were unaware of the risk-factor status of the deceased person. The extent of atherosclerosis was expressed as the mean of the values assigned to the vessels by the three pathologists.
Essentially all persons studied had fatty streaks in the aorta. The prevalence of fatty streaks in the coronary arteries was 50 percent in persons from two to 15 years of age and 85 percent in persons from 21 to 39 years of age. The prevalence of raised fibrous plaque lesions in the aorta increased with age, reaching 60 percent in persons 26 to 39 years of age. The prevalence of raised plaques in the coronary vessels was 8 percent in persons from two to 15 years of age and 69 percent in persons from 26 to 39 years of age. With both types of lesions, there was a trend toward involvement of an increasing percentage of the intimal surface with increasing age.
In correlating the extent of vascular lesions with antemortem risk factors, study results showed a positive and significant association with body mass index, systolic blood pressure (except for fibrous plaques in the aorta), diastolic blood pressure (except for fibrous plaques in the coronary arteries), total cholesterol, LDL cholesterol and serum triglyceride levels. Persons with a known history of cigarette smoking did not have a greater prevalence of coronary or aortic lesions compared with persons who did not smoke. However, smokers did have a greater mean percentage of intimal surface area involvement for both coronary vessels and the aorta. Collectively, the extent of fatty-streak lesions in coronary arteries was 8.5 times greater in persons with three or four risk factors, and the extent of fibrous plaques in the arteries was 12 times as great, compared with persons with no identifiable risk factors.
The authors conclude that the extent of coronary and aortic lesions in children and young adults significantly correlates with the presence of cardiovascular risk factors, including body mass index, systolic blood pressure, serum LDL cholesterol level, triglyceride concentration and cigarette smoking. They believe their data support the Framingham Study, which determined that multiple cardiac risk factors have a synergistic effect on morbidity and mortality from cardiovascular disease. In addition, cigarette smoking appears to adversely affect the extent of coronary disease in persons with other risk factors.
editor's note: Data from the Bogalusa Heart Study certainly suggest that known risk factors for coronary disease begin to have an effect in early adulthood and possibly even in childhood. This suggestion is in keeping with an earlier report (the “PDAY” study) that found an association between atherosclerotic lesions in adolescents and smoking and high cholesterol levels. Data from the Bogalusa Study bring up the question of screening and intervention for cardiac disease in young adults and children. There still is no evidence that early intervention, such as treating hypertension in younger patients, is efficacious in the long run. Cholesterol screening and medical treatment of hyperlipidemia in children remain controversial interventions and are not practiced by the majority of clinicians. However, interventions such as counseling against tobacco use and encouraging healthy dietary habits and exercise appear to be reasonable and potentially effective ways to reduce the future risk of heart disease.—j.k.