Brown adipose tissue and its relationship to bone structure in pediatric patients.

CONTEXT Emerging evidence suggests a possible link between brown adipose tissue (BAT) and bone metabolism. OBJECTIVE The objective of this study was to examine the relationships between BAT and bone cross-sectional dimensions in children and adolescents. DESIGN This was a cross-sectional study. SETTING The study was conducted at a pediatric referral center. PATIENTS Patients included 40 children and teenagers (21 males and 19 females) successfully treated for pediatric malignancies. INTERVENTIONS There were no interventions. MAIN OUTCOME MEASURES The volume of BAT was determined by fluorodeoxyglucose-positron emission tomography/computed tomography. Measures of the cross-sectional area and cortical bone area and measures of thigh musculature and sc fat were determined at the midshaft of the femur. RESULTS Regardless of sex, there were significant correlations seen between BAT volume and the cross-sectional dimensions of the bone (r values between 0.68 and 0.77; all P ≤ 0 .001). Multiple regression analyses indicated that the volume of BAT predicted femoral cross-sectional area and cortical bone area, even after accounting for height, weight, and gender. The addition of muscle as an independent variable increased the predictive power of the model but significantly decreased the contribution of BAT. CONCLUSIONS The volume of BAT is positively associated with the amount of bone and the cross-sectional size of the femur in children and adolescents. This relation between BAT and bone structure could, at least in part, be mediated by muscle.