EFFECT OF BODY-SIZE, PONDEROSITY, AND BLOOD-PRESSURE ON LEFT-VENTRICULAR GROWTH IN CHILDREN AND YOUNG-ADULTS IN THE BOGALUSA HEART-STUDY

Background The measurement of left ventricular mass (LVM) is important because individuals with increased LVM are at increased risk for card iovascular diseases, including myocardial infarction and congestive he art failure. There are limited longitudinal data on the acquisition of LVM in children and young adults and the relative importance of sex, growth, excess body weight, and blood pressure (BP) on change in LVM. Methods and Results The study cohort consisted of a cross section of 1 60 healthy children and young adults 9 to 22 years of age at first exa m in the biracial community of Bogalusa, La. All had stable BP levels recorded over a 2- to 3-year period. Repeated examinations were perfor med 4 to 5 years apart. At each exam, 6 BPs were obtained with a mercu ry sphygmomanometer by trained examiners. The mean of the observations was used, with the fourth Korotkoff phase serving as the measure of d iastolic BP. Anthropometric data, including height (HT), weight (WT), and triceps skin fold thickness (TSF), were also obtained, and M-mode echocardiograms were performed. Ponderal index (PI=WT/HT3) was used as a measure of weight-for-height. Tracking of HT (r=.68 to .76), WT (r= .73 to .82), PI (r=.77 to.89), TSF (r=.70 to .80), BP (r=.47 to .60), and LVM (r=.40 to .70) was strong in both series (P<.0001). LVM indexe d for linear growth (LVM/HT2.7) tracked in females (r=.56, P<.0001) bu t not in males. In univariate cross-sectional analyses, LVM/HT2.7 corr elated with WT, PI, and TSF in both sexes (r=.21 to .60, P<.05) and wi th systolic BP (SEP) in females (r=.23, P<.05). WT was the only indepe ndent correlate of LVM/HT2.7 in both sexes in multivariate cross-secti onal analysis in a model containing age, SEP, WT, and TSF as independe nt variables (r(2)=.08 to .28, P<.02). In longitudinal univariate anal yses, initial measurements of WT, PI, and TSF predicted final LVM/HT2. 7 in both sexes (r=.28 to .56, P<.01), and SEP was significant for fem ales (r=.27, P<.05). In multivariate analyses, initial WT was associat ed with final LVM and LVM/HT2.7 in both sexes (r(2)=.27 to .54, P<.01) . Finally, baseline LVM correlated with final SEP in both sexes (r=.21 to .27, P<.05), and initial LVM/HT2.7 correlated with final SEP in fe males (r=.26, P<.05) with a trend for males (r=.17).Conclusions These data indicate that linear growth is the major determinant of cardiac g rowth in children and that excess weight may lead to the acquisition o f LVM beyond that expected from normal growth. Increased mass may also pre cede the development of increased BP. The development of obesity may therefore be a significant, and possibly modifiable, risk factor f or developing left ventricular hypertrophy and hypertension, risk fact ors for cardiovascular morbidity and mortality.