Validation of BodPod in Pediatric Anorexia Nervosa (PADAAM)

Accuracy of Air Displacement Plethysmography Compare to Dual X-ray Absorptiometry (DXA) in Girls With Anorexia Nervosa

Anorexia nervosa is a severe cause of undernutrition. It leads to a dramatic decrease of weight with an important modification of the body composition. During the renutrition phase, disharmonious body composition recovery is a relapse factor. Dual X-ray absorptiometry (DXA) is the gold standard to study body composition in children with anorexia nervosa. But, due to technical limits, DXA analysis needs to take in account a potential failure to thrive with an adjustment on height. Moreover DXA needs an irradiation which does not allow close repeat measurements. Since several years, a simple, non-invasive, non-irradiant method for measure of body composition has been developed in pediatrics: the air displacement plethysmography (ADP). Actually, only one device is available for this measurement: the BodPod®. However, feasibility and accuracy of ADP compare to DXA have not been evaluated in pediatric anorexia nervosa. The aim of this study is to compare the accuracy of BodPod® compare to DXA in girls with anorexia nervosa.

Each patient included will have one measure of body composition by Air Displacement Plethysmography (ADP) during the initial consultation in the referent center for food disorders of Lyon and one year later.

The accuracy of Air Displacement Plethysmography (ADP) will be compare to Dual X-ray Absorptiometry (DXA) according to the percentage of body fat mass measurement. The hypothesis will be validating if difference in percentage in body fat mass between ADP and DXA is below the 4%. The measurement will be done two times at 1 year interval

Acceptability of Air Displacement Plethysmography (ADP) by the patient compared to Dual X-ray Absorptiometry (DXA)

The questionnaire includes 3 questions after the ADP using simple analog visual scales adapted to children comprehension. The measurement will be done two times at 1 year interval

The difference between percentage of body fat mass will quantified between ADP and BEI. The measurement will be done two times at 1 year interval

Inclusion Criteria: Female patients aged between 8 and 18 years Female with a diagnosis of anorexia nervosa according to the DSM V classification, restrictive type or hyperphagic / purgative access type, evolving for less than 3 years. Female who received explanations adapted to their level of understanding for this study Female who expressed their consent to participate to this study Female whose parents or holders of parental authority have been informed and signed free and informed consent Female affiliated to a social security scheme Exclusion Criteria: Patients with psychotic symptoms Patients with claustrophobia Patients with severe respiratory disease

Centre REférent pour l'Anorexie et les Troubles du Comportement Alimentaire de Lyon (CREATyon) - Hôpital Neurologique Pierre Wertheimer - Hospices Civils de Lyon