Objective: To determine whether bone mineral density (BMD) loss can be reversed 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 first evaluated by dual-energy x-ray absorptiometry in lumbar spine and femoral neck consecutively from 1997 until 1999 and reexamined after 6 to 30 months. Results were compared with normative values of bone mass.
Results: Patients with poor outcome (n = 44) had a bone mass loss. Patients with good short-term outcome were divided in two groups. The group with normal BMD at first evaluation (n = 41) had a bone mass gain per year of 3.0% at lumbar spine 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 zscore at first evaluation, the only predictor of BMD increase was the first z score both at the lumbar spine (coefficient R = 0.64; p < .001) and at the femoral neck (coefficient R = 0.5; p < .001).
Conclusions: There is a catch-up effect in adolescent patients with low BMD but good short-term outcome.