CONTEXT:

Anorexia nervosa is complicated by severe bone loss and clinical fractures. Mechanisms underlying bone loss in adults with anorexia nervosa include increased bone resorption and decreased formation. Estrogen administration has not been shown to prevent bone loss in this population, and to date, there are no approved, effective therapies for this comorbidity.

OBJECTIVE:

To determine whether antiresorptive therapy with a bisphosphonate alone or in combination with low-dose transdermal testosterone replacement would increase bone mineral density (BMD) in women with anorexia nervosa.

DESIGN AND SETTING:

We conducted a12-month, randomized, placebo-controlled study at a clinical research center.

STUDY PARTICIPANTS:

Participants included 77 ambulatory women with anorexia nervosa.

INTERVENTION:

Subjects were randomized to risedronate 35 mg weekly, low-dose transdermal testosterone replacement therapy, combination therapy or double placebo.

MAIN OUTCOME MEASURES:

BMD at the spine (primary endpoint), hip, and radius and body composition were measured by dual-energy x-ray absorptiometry.

RESULTS:

Risedronate increased posteroanterior spine BMD 3%, lateral spine BMD 4%, and hip BMD 2% in women with anorexia nervosa compared with placebo in a 12-month clinical trial. Testosterone administration did not improve BMD but increased lean body mass. There were few side effects associated with either therapy.

CONCLUSIONS:

Risedronate administration for 1 yr increased spinal BMD, the primary site of bone loss in women with anorexia nervosa. Low-dose testosterone did not change BMD but increased lean body mass.