Oral contraceptives partially protect from bone loss in young women with anorexia nervosa

Objective: To evaluate the potentially protective effects of oral contraceptives (OC) on bone loss in a large population of young women with anorexia nervosa (AN).

Design: Cross-sectional study.

Setting: University hospital.

Patient(s): Three hundred and five patients with AN (99 of them using OC) and 121 age-matched controls.

Intervention(s): None.

Main outcome measure(s): Areal bone mineral density (aBMD) evaluated by dual-energy X-ray absorptiometry and bone turnover markers, with leptin evaluated concomitantly.

Result(s): Although the AN patients taking OC presented lower aBMD compared with the controls at all bone sites, the whole body excepted, their aBMD values were systematically higher than those of AN patients who were not taking OC for the whole body and the lumbar spine, femoral neck, hip, and radius. These differences persisted after multiple adjustments. Preservation of aBMD improved with longer durations of OC use and shorter delays between disease onset and the start of OC. Moreover, patients with the lowest body mass index showed the best bone tissue responses to OC. Bone formation markers were systematically lower in the two groups of patients with AN compared with the controls. The markers of bone resorption were normalized in AN patients using OC.

Conclusion(s): Although OC use does not provide total protection of aBMD, our data suggest that OC might be prescribed for young women with AN to limit their bone loss.