43 - Visceral Adiposity Associated with Lower Bone Density in a Pediatric Mortality Sample from New Mexico

Poster Board Number: 43
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Abstract Body : Research comparing the association of various measurements of adipose mass with bone density in pediatric samples is limited, with most studies choosing to measure adiposity in only one way. Studies that have examined measures of abdominal adiposity, albeit mostly among adults, have found positive, negative, or no relationship between adiposity and BMD. Research that quantifies adiposity through coarse measures like body mass index (BMI) or waist circumference, while useful for screening for other health risks, may not fully capture the aspects of fat mass that are most closely related to bone health. The purpose of this study is to test which measures of adiposity – BMI, subcutaneous adipose tissue (SAT), visceral adipose tissue (VAT), or the VAT/SAT ratio – are more closely related to BMD in a pediatric sample of decedents from New Mexico.

This study includes 526 individuals 6 months to 20.99 years old that died and underwent postmortem computed tomography (PMCT) at the University of New Mexico OMI between 2011 and 2019. One of the authors, ECH, measured the axial area of VAT and SAT using 3D Slicer at the level of the fourth lumbar vertebra (L4). BMD of L4 and the proximal femur were quantified using Hounsfield Units as a proxy measure. BMD, BMI, VAT, and SAT were z-standardized by sex and age using the sample mean and standard deviation. Linear regression was used to examine the relationship between BMD, BMI, VAT, SAT, and VAT/SAT; with each of these as a dependent variable in four separate models.

At L4, there is a negative linear relationship between VAT and BMD, but a positive linear relationship between BMI and BMD. There were no significant relationships between measures of adiposity and BMD of the proximal femur. BMI has a significant positive relationship to SAT, but a significant negative relationship to the VAT/SAT ratio.

These results are consistent with other studies from children and adolescents that have found a negative relationship between visceral adiposity and BMD. Further, BMI seems to be more accurately quantifying subcutaneous, rather than visceral, adiposity and is likely not a good predictor of bone metabolism, independent of other risk factors. Along with other health problems (e.g. sleep apnea, fatty liver disease, diabetes mellitus, and heart disease) that have become more common among children and adolescents, low bone density is another comorbidity of pediatric obesity that can have a lifelong impact. A better awareness among clinicians of the relationship between visceral adiposity and low BMD is useful for screening pediatric patients.