The study is designed to use existing data from the Bogalusa Heart Study, a community based study of the early natural history of CVD in an entire free-living population of white and black children, adolescents and young adults, to examine the relationships between obesity and other risk factors for cardiovascular disease (CVD). The design of the Bogalusa Study is mixed; cross-sectional and longitudinal data have been collected. Using data from surveys conducted during 1978-79 (n=3,590 children and adolescents, aged 15-17 yrs) and 1984-86 (n=3,175 children, adolescent and young adults, aged 8-27 yrs), in cross-sectional analyses, we aim to determine critical levels of total body fat and fat pattern that are associated with elevated CVD risk factors in young adults. Also, in longitudinal analyses, we aim to determine whether childhood and adolescent obesity is predictive of subsequent elevated levels of CVD risk factors and to determine the extent to which change in body composition is related to change in risk factors. The CVD risk factors to be examined in relation to obesity include systolic and diastolic blood pressure, total cholesterol, triglycerides, lipoproteins (HDL, LDL, VLDL), lipoprotein ratios and serum insulin. Several indices of body composition (obesity) will be examined including total body percent fat, skinfold and body mass index percentile rankings, and fat pattern (logN (subskf/triskf) and we intend to compare their tracking, sensitivity and specificity, and positive and negative predictive values. The complete data sets from each survey will be used to calculate age-, race- and sex-specific percentiles for skinfolds, BMI and CVD risk factors in children and adolescents. In a recent investigation in children and adolescents we have shown males with >_25% fat and females with >_30% fat have a significantly greater risk of elevated CVD risk factors than their leaner peers. In the proposed study we intend to use the cross-sectional data from males and females collected during 1984-1986 to test the hypothesis that similar levels of body fat will be associated with greater risk of elevated CVD risk factors in young adults. For this analysis, elevated levels of CVD risk factors will be defined according to nationally recommended criteria for adults. The longitudinal analyses will be conducted using data from 1900 males and females who were first examined in 1978-1979 as children and adolescents and who were retested 5-8 years later in 1984-1986 as adolescents and young adults. Although we have previously established critical levels of body fat associated with elevated risk factors in children and youth, the degree to which these levels of body fat track and are predictive of future levels of risk factors is not known. The direct comparisons of tracking, sensitivity, specificity, and positive and negative predictive value among the different indices of obesity will allow us to assess whether childhood and adolescent obesity is predictive of future risk and which index of obesity is most useful. The information to be gained from the proposed analyses is unique and essential for the design of screening programs for early intervention and prevention of CVD.
