Context: Both Anorexia nervosa (AN) and depression are associated with osteoporosis. We hypothesized that adolescent girls with AN and depression will have lower BMD than anorexic girls without depression.

Objective: To investigate whether depression is an independent risk factor for osteoporosis in anorexic adolescent girls.

Design: Cross-sectional study.

Setting: University Children's Hospital in Bialystok (Poland), from October 2002 - September 2003.

Participants: 45 Caucasian anorexic girls aged 13 - 23 yr; fourteen with comorbid depression (based on Hamilton Depression Rating Scale (HAM-D) and Montgomery-Asberg Depression Rating Scale (MADRS)) and 31 anorexic girls without depression, matched by age, Tanner stage, weight, height, calcium intake and duration of AN.

Main Outcome Measures: Total body and lumbar spine bone mineral density (TB BMD, LS BMD), fat mass (FM) and lean mass (LM) assessed using dual energy x-ray absorptiometry (DXA) were compared between AN girls with and without depression.

Results: BMD was reduced in both groups, relative to reference data, but girls with AN and depression had lower BMD than those with AN alone (lumbar spine Z-scores -2.6 ± 0.3 vs. -1.7 ± 0.3 SD; P = 0.02) (mean ± SEM). Quantitative assessment of depression correlated independently with TB BMD (r = -0.4; P < 0.05) and LS BMD (r = -0.6; P < 0.001).

Conclusion: Anorexic girls with depression are at higher risk of osteoporosis than those without depression. The mechanisms responsible for decreased BMD in depression are not known. Independent treatment of the depressive disorder in AN may partly alleviate the bone fragility.