Pediatric Epidemiology of Cardiovascular Disease Risk Factors (Project Heartbeat)

BACKGROUND:

Both the pathologic precursors of atherosclerosis and the development of its major risk factors -- blood pressure, blood lipids, and cigarette smoking -- are often far advanced before age 20 or within the period from birth or conception through adolescence. In 1990, there was growing interest in understanding these aspects of human biology and in devising appropriate preventive measures.

In 1990, knowledge about the risk factors during childhood and adolescence was based mainly on cross-sectional surveys, from which very striking and consistent patterns of change with age were inferred, and from which reference values for screening and management were derived. Both growth and sexual maturation influence these patterns strongly, yet these risk factors had only recently been taken into account in 1990, only partially in screening recommendations for blood pressure and not at all for cholesterol.

DESIGN NARRATIVE:

Subjects were selected by simple random sampling. Data were collected on dependent variables including blood pressure, heart rate, echocardiography, Doppler flow, blood lipids, and smoking. Independent variables included growth, diet and nutrition, electrolytes, physical activity and fitness, personal, family, and social history, and bone age. Most observations were recorded at four month intervals. There was a six month pretest recruitment period, four years of cycled measurements and data collection, and six months of analysis and reporting. Curves for both velocity and acceleration of growth for attained levels of blood pressure, blood lipids, and smoking were determined as were longitudinal relationships between individual growth curves of blood pressure, echocardiographic measures, physical growth, sexual maturation, body composition, diet, physical activity, and social factors.