Bone mineral density in Anorexia Nervosa versus Avoidant Restrictive Food Intake Disorder.

Area of Science:

• Pediatric Endocrinology
• Nutritional Science
• Bone Metabolism

Background:

• Avoidant Restrictive Food Intake Disorder (ARFID) and Anorexia Nervosa (AN) are eating disorders causing significant underweight in children and young people (CYP).
• While the link between low bone mineral density (BMD) and underweight in AN is established, less is known about BMD in ARFID.
• Underweight CYP with these disorders are at risk for compromised bone health.

Purpose of the Study:

• To investigate and compare bone mineral density (BMD) in underweight children and young people diagnosed with ARFID versus Anorexia Nervosa (AN).
• To determine if the diagnosis of ARFID or AN, or anthropometric measures like Body Mass Index (BMI), are more strongly associated with BMD outcomes.
• To assess the clinical significance of BMD in ARFID compared to the well-documented impact in AN.

Main Methods:

• A retrospective analysis of bone mineral density (BMD) measures obtained via DXA scans was conducted.
• The study included underweight patients (age > 5 years, underweight for ≥ 6 months) referred to a pediatric eating disorder clinic between 2014 and 2019.
• Data from 134 patients (118 with AN, 16 with ARFID) were analyzed, focusing on BMD z-scores and their correlation with BMI, BMI z-score (BMIz), and diagnosis.

Main Results:

• Of 134 patients, 118 had AN and 16 had ARFID. ARFID cases were more likely to be male, have lower BMI and BMIz, and a longer duration of underweight.
• Both BMI and BMIz were significantly positively associated with BMD z-score and bone mineral areal density z-score across all patients.
• Crucially, no significant association was found between BMD and the diagnosis (ARFID vs. AN), even when matched for age, sex, and pubertal status.

Conclusions:

• Low bone mineral density (BMD) in underweight children with ARFID and AN is primarily associated with BMI, not the specific eating disorder diagnosis.
• BMD appears to be a critical health concern in ARFID, potentially as significant as in AN.
• Further research is warranted to explore the underlying mechanisms and develop targeted interventions for bone health in these pediatric populations.