Fat-free mass as a determinant of left ventricular mass in children: The Muscatine Study

To assess the relationship of somatic growth to heart growth, associations were examined among body composition, blood pressure, androgens, sexual maturation, and left ventricular mass (LVM) during early puberty in 123 children, 7-12 years of age. All subjects underwent anthropometry, random-zero blood pressure measurements, hormone determination of androgens, physician's examination to determine sexual maturation, and echocardiographic examinations. Subjects then repeated these procedures 1 year later. Data were examined cross-sectionally (year 1, year 2) and longitudinally (Δ = year 2 minus year 1). The strongest correlations with LVM were among weight and fat-free mass (FFM) (r = 0.60 to 0.83). In males, cross-sectional predictors of LVM were FFM and stage of sexual maturation (r² = 0.49 to 0.65). Δ LVM was best predicted in males by Δ testosterone and Δ weight (r² = 0.22). In females, FFM was the strongest cross-sectional predictor of LVM (r² = 0.70). Δ LVM was best predicted in females by Δ FFM and Δ height (r² = 0.27). When males and females were pooled, gender did not predict LVM in any of the models. The results suggest that FFM is an important predictor of LVM in circumpubertal children. Boys and girls do not significantly differ in LVM once normalized for FFM. © 1996 Wiley-Liss, Inc.