IntroductionThe association between skin-fold thicknesses in children and adolescents and elevated levels of variables considered to be indicative of risk for cardiovascular disease (CVD) in adults has been found by several investigators. '-5 In population-based studies of children and adolescents, for example, excess subcutaneous fatness has been associated with elevated blood pressure (BP),' 2,6 serum lipids, and lipoprotein fractions,2-4 and the clustering of these variables.5 Although the results of these studies demonstrate that elevated levels of CVD risk factors often accompany excess body fat in youth, the absolute level of body fat corresponding to significant risk for high BP, serum lipids, low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) cholesterols is not known.Although children and youth with triceps skinfolds 2 the 85'h percentile for age and sex are at greater risk for high BP than children with lower skinfold thicknesses,1 such a rank-ordered definition of obesity implies that the absolute level of body fatness associated with increased risk is variable. Recent work has shown that the 85th percentile may not be indicative of obesity in all samples, because skinfold thicknesses at a given percentile correspond to different levels of body fat at different ages.7,8 The 85th skinfold percentile, for example, represents fatness levels ranging from 17% to 22% in children and from 25% to 34% in adolescents.8In addition to the discrepancy between relative and absolute definitions of obesity, the triceps skinfold site has been shown to be unrelated to BP in youth when statistical adjustments were made for subscapular skinfold thickness.9Moreover, a trunkal fat pattern, independent of general body fatness, is related to high levels of LDL and VLDL and to low levels of high-density lipoprotein (HDL) cholesterol in 6-to 18-year-old youth.'0The independent effects of centripetal localization of subcutaneous fat on BP9-1" and adverse lipoprotein profiles"' make it important to control the potential confounding effect of fat patterning when the relation between total body fat and CVD risk factors in youth is evaluated.The purpose of the present study was to determine the level of body To determine the critical level of body fat associated with elevated CVD risk factor variables, the males and females were subsequently grouped by level ofpercent fat. Males were divided into the following five fatness groups: <10% (n = 217), 10% to 14.9% (n = 575), 15% to 19.9% (n = 436), 20% to 24.9% (n = 192), and >25% (n = 247). Females were grouped by body fat as follows: <20% (n = 547), 20% to 24.9% (n = 493), 25% to 29.9% (n = 313), 30% to 34.9% (n = 192), and .35% (n = 108).An index of trunk-to-limb fat distribution was computed as the natural logarithm of the subscapular/triceps skinfold thickness ratio.2-Because absolute standards for children and youth do not exist for this index of fat patterning, age-, sexand race-specific percentiles for the present sample were developed. Fat-patterning quint...

Background-Physical activity is important for weight control and good health; however, activity levels decline in the adolescent years, particularly in girls.

Serum lipids (total cholesterol and triglycerides) and lipoprotein cholesterol fractions (low density lipoprotein (LDL) cholesterol, very low density lipoprotein (VLDL) cholesterol, and high density lipoprotein (HDL) cholesterol) have been measured approximately every 3 years on children and young adults since 1973-1974 in Bogalusa, Louisiana, a community of approximately 22,000 individuals, one-third of whom are black and two-thirds of whom are white. A total of 1,586 children were examined both at baseline (1973-1974) and at the most recent survey (1984-1986), providing 12 years of follow-up. The decreases in levels noted during puberty for total cholesterol and LDL cholesterol, primarily for boys, were followed by a rise until age 26 years. HDL cholesterol levels, particularly for white boys, continued to drop after age 14 years, yielding increasingly high LDL cholesterol/HDL cholesterol ratios. Tracking, as measured by both correlation coefficients and persistence at extreme quartiles, was evident for all of the lipids and lipoproteins. The 12-year correlation coefficients were greatest for LDL cholesterol and no trend in the magnitude of the correlation coefficients with age was noted. Tracking for HDL cholesterol was better after age 9 years, particularly for white males. Approximately 50% of those children who had total cholesterol levels or LDL cholesterol levels above the 75th percentile at baseline remained elevated 12 years later. For HDL cholesterol, a trend with age was noted for white boys: 42% of those aged 9-14 years in the lower most quartile persisted in this rank 12 years later. The best predictor of follow-up lipid or lipoprotein level was baseline level. The next best predictor was increase in weight as defined by weight/height, an index of obesity. That serum lipid and lipoprotein levels continue to track from childhood into young adulthood points to the necessity of measurement early in life and, where indicated, the introduction of preventive and interventional programs aimed at developing healthy lifestyles.