Elevated Early Adolescent Body Fat Measures Predict Increased Blood Pressure after Ten Years in Black and White Girls

Cardiometabolic risk has its roots in childhood. Given the huge burden of adult chronic disease, the identification of simple predictors of risk factors such as high blood pressure early in life is crucial to the development of preventive strategies. We investigated whether pre‐adolescent (ages 9–10 years) measures of body fat predict late adolescent (ages 17–20 years) blood pressure and whether there may be racial differences in the efficacy of particular early measures of body fat for predicting blood pressure in older adolescents. Previously collected data from the NHLBI's Growth and Health Study, a bi‐racial longitudinal cohort of girls initially 9–10 years of age were used. The independent effects of three distinct measures of early adolescent body fat on blood pressure in late adolescence were examined: BMI, waist circumference (WC) at minimum waist, and percent body fat (%BF) by bioelectrical impedance analysis. Girls with complete data (n=941, white; n=1001, black) for baseline BF measures, relevant confounders, and follow‐up blood pressure (systolic [SBP] and diastolic [DBP]) at 17–20 years of age were included. Analysis of covariance modeling was used to compare mean SBP and DBP in black and white girls in late adolescence in association with early adolescent measures of body fat, while adjusting for potential confounding. In late adolescence, SBP increased linearly across quintiles of all BF measures collected at 9–10 years of age. Black girls in Q5 of BF had higher SBP levels than whites (BMI: 113.2 vs 111.9 mm Hg; %BF: 112.8 vs. 110.2 mm Hg; WC: 113.3 vs. 112.2 mm Hg). This pattern differed from that observed in the lowest quintiles of body fat: black and white girls in Q1 had similar SBP levels in later adolescence (BMI: 107.0 vs. 107.1 mm Hg; WC: 107.5 vs. 107.3 mm Hg) and in Q1 of %BF, SBP of white girls slightly exceeded that of black girls (109.1 vs. 108.8 mm Hg). Across quintiles of BMI, there were large increases in BP (blacks 6.1 mm Hg; whites: 4.8 mm Hg) with p‐trend <0.0001 for both. In general, there were greater body fat‐related differences in SBP (but not DBP) in blacks than in whites. We examined the prediction of SBP and DBP associated with early adolescent risk factors. For SBP, for example, we found that the strongest predictors among white girls were BMI, baseline height, fruit and vegetable intake, and hours of television watched per day. In blacks, the strongest predictors were BMI, baseline height, fruit and vegetable intake, dietary fiber, and age at menarche. For DBP, dietary protein was also a predictor for both blacks and whites. These results suggest that different sets of risk factors may predict BP change in blacks and whites during this critical period of adolescence. Early adolescent BMI was a stronger and more consistent predictor of SBP (and to a lesser extent, DBP) than either %BF or waist circumference. These results suggest that in both racial groups, simple measures of early adolescent body fat taken as early as 9–10 years of age may be useful for identifying girls at risk of adult high blood pressure. Support or Funding Information National Institutes of Health 2T32HL007969‐11