Child and Adolescent Trial for Cardiovascular Health (CATCH)

BACKGROUND:

Coronary atherosclerosis begins in childhood and is expressed in adulthood as angina pectoris, myocardial infarction, or sudden death. The earliest lesion in the vascular system is the fatty streak, characterized by an accumulation of lipids in the intima. These lesions are present in the vessels of infants and young children. Whether these fatty streaks are precursors of more complex lesions is controversial. However, fibrous plaques, intimal lesions consisting of a central core of extracellular lipids covered with a cap of fibromuscular tissue, are frequently seen in children by 15 years of age. In addition, necropsy studies of United States battle casualties confirm the presence of advanced coronary lesions in young adults. Thus, it appears that the atherosclerotic process is well established in the American population by young adulthood.

Epidemiologic studies in adults have found that associated with the development of coronary artery disease are a number of risk factors including age, sex, hypercholesterolemia, hypertension, cigarette smoking, diabetes, a family history of coronary artery disease, obesity, lack of physical activity, and perhaps coronary prone behavior. Of the modifiable factors, hypercholesterolemia, hypertension, and cigarette smoking have the greatest predictive value.

A small reduction of serum cholesterol levels in all children by a modest diet change, it has been hypothesized, would reduce coronary heart disease. More severe dietary restriction, in some cases in conjunction with medication, is recommended for very high-risk pediatric populations only. In addition, surveillance of blood pressure, avoidance of cigarette smoking and overweight, and regular physical exercise are prudent recommendations for all children.

The National Children and Youth Fitness Study (NCYFS) offered new standards for measuring fitness, profiled youth exercise habits, and helped to explain the contribution of exercise to fitness. Nationwide, 8,000 fifth- through twelfth-graders in 140 schools in 19 states participated in the study between February and May 1984. Findings revealed that these youths had substantially more body fat than their counterparts in the 1960's and that approximately half of the students did not perform sufficient physical activity to maintain effective cardiorespiratory functioning. Results from the 1985 national survey of drug use among high school students indicate that most initial experiences with smoking occur before high school, with 13 percent of students beginning prior to tenth grade. Substantial increases in smoking occur between seventh and eighth grade and inner city Hispanic students show higher smoking rates than white or Black inner city youth.