Several lines of evidence provided the rationale for intervening in children. A large body of autopsy and pathologic evidence had accumulated showing that atherosclerosis, including fatty streaks, increased surface involvement, and advanced microscopic lesions, began in childhood. Blood cholesterol levels tracked from childhood to adulthood, with tracking correlations ranging from .6 to .8. Therefore, a high proportion of children with high levels of cholesterol have high levels as adults. Family clustering of risk factors had also been reported. Studies showed 2-3 times increased prevalence of coronary heart disease in adult relatives of children with high cholesterol compared to children with normal cholesterol, and 2.2 times increased prevalence in high cholesterol in children who had a parent or grandparent with premature coronary heart disease compared with children who did not have a family history of premature heart disease. Finally, there was high likelihood that environmental influences on coronary heart disease risk factors had their behavioral antecents in childhood. Thus, dietary habits which contributed toward elevated blood cholesterol levels were likely to have developed early in life, and it was hoped that behavioral change achieved during childhood was likely to persist into adulthood.