Adolescent anorexia nervosa: The catch-up effect in bone mineral density after recovery

Objective: To determine whether bone mineral density (BMD) loss can be reve rsed in adolescent anorexic patients. Method: A prospective study with 108 anorexia nervosa patients (DSM-IV) from 12 to 17 years of age at the Eating Disorders Unit in the Hospital Clinic of Barcelona (Spain). They were firs t evaluated by dual-energy x-ray absorptiometry in lumbar spine and femoral neck consecutively from 1997 until 1999 and reexamined after 6 to 30 month s. Results were compared with normative values of bone mass. Results: Patie nts with poor outcome (n = 44) had a bone mass loss. Patients with good sho rt-term outcome were divided In two groups. The group with normal BMD at fi rst evaluation (n = 41) had a bone mass gain per year of 3.0% at lumbar spi ne and 0.5% at femoral neck. The group with low BMD at first evaluation (n = 23) had an increase per year of 9.1% at lumbar spine and 4.5% at femoral neck. In a multiple linear regression analysis with the variables body mass Index, age, months with menstruation, and BMD z score at first evaluation, the only predictor of BM increase was the first z score both at the lumbar spine (coefficient R = 0.64; p < .001) and at the femoral neck (coefficien t R = 0.5; p < .001). Conclusions: There is a catch-up effect in adolescent patients with low BMD but good short-term outcome.