An Analysis of Muscle Quality and Its Relationship to Bone Density and Obesity in a Pediatric Autopsy Sample From New Mexico

Introduction Muscle quality metrics are useful indicators of physical activity and overall health but have been underexamined in pediatric samples. This study investigates associations between skeletal muscle area and density, bone mineral density (BMD), and obesity‐related factors in a pediatric autopsy sample from New Mexico. Methods We analyzed postmortem computed tomography (PMCT) data of individuals aged 5–20.99 years at time of death. Skeletal muscle indices—muscle area relative to stature—were measured for the psoas major and thigh muscles at femoral midshaft. Muscle density was also calculated using Hounsfield units at these sites. Multiple linear regression was used to test the relationship between these proxies of muscle quality to BMD, obesity, metabolic dysfunction‐associated steatotic liver disease (MASLD), sex, race/ethnicity, age at death, and mode of death. Results Skeletal muscle indices and density were positively associated with femoral BMD in a pooled‐sex sample and lumbar BMD in females. Skeletal muscle indices were positively associated with obesity and muscle density was negatively associated with levels of subcutaneous adiposity. A reduced psoas muscle index was significantly associated with MASLD in males. Males have greater skeletal muscle indices than females, but the sexes have similar muscle density. Native American individuals exhibited lower muscle indices compared to Hispanic and non‐Hispanic White peers. Conclusions Muscle quality is positively related to skeletal health in girls and negatively associated with MASLD in boys. These findings underscore the importance of early‐life physical activity and structural context in shaping musculoskeletal health.