Contribution of Body Composition Measures to the Increased Left Ventricular Mass Index in Young Adult Black and White Females

<b>Objective:</b> We aimed to determine the contribution of various types of body composition measures to the increased left ventricular mass index (LVMI) in young adult females. <b>Methods:</b> Data from the National Growth and Health Study (NGHS), including dual-energy x-ray absorptiometry (DEXA), magnetic resonance imaging (MRI), and echocardiogram, were analyzed (<i>N</i> = 589, 54.8% Black, mean age: 24.9 ± 0.7 years). Logistic and linear regressions were conducted to assess for the contribution of fat mass (FM) and fat-free mass (FFM) by DEXA and subcutaneous abdominal adipose tissue (SAT) mass and visceral adipose tissue (VAT) volume by MRI in relation to the increased LVMI or left ventricular hypertrophy (LVH; LVMI ≥ 38.6 g/m^2.7). <b>Results:</b> FM (<i>β</i> ± SE: 0.025 ± 0.002, <i>p</i> < 0.01, adjusted <i>R</i> ² = 0.313), FFM (0.059 ± 0.003, <i>p</i> < 0.01, adjusted <i>R</i> ² = 0.374), SAT (0.054 ± 0.005, <i>p</i> < 0.01, adjusted <i>R</i> ² = 0.291), and VAT (0.194 ± 0.019, <i>p</i> < 0.01, adjusted <i>R</i> ² = 0.256) were each significantly associated with the increased LVMI, with FFM having the greatest association. Black race was associated with the increased LVMI in models involving individual fat mass types (0.055 ± 0.020, <i>p</i> < 0.01 for FM; 0.054 ± 0.021, <i>p</i> = 0.01 for SAT; 0.119 ± 0.021, <i>p</i> < 0.01 for VAT). In logistic models considering all mass types, FFM (OR [95% CI]: 1.62 [1.46-1.79], <i>p</i> < 0.01) and systolic blood pressure (SBP) (1.04 [1.01-1.07], <i>p</i> < 0.01) were significant contributors to LVH (area under the receiver-operator characteristic curve 0.847), and only FFM was a significant contributor in the corresponding linear regression (<i>β</i> ± SE: 0.059 ± 0.003, <i>p</i> < 0.01, adjusted <i>R</i> ² = 0.374). <b>Conclusions:</b> FFM had the greatest association with LVH and LVMI, confirming previously published data. Through the use of MRI, we found that neither subtype of abdominal fat mass (SAT and VAT) better explained the variance in LVMI than FFM.