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Premenopausal osteoporosis, an overlooked consequence of anorexia nervosa

Cleveland Clinic Journal of Medicine. 2011 January;78(1):50-58 | 10.3949/ccjm.78a.10023
January 1, 2011|Cleveland Clinic Journal of Medicine
Kathryn Teng, MD, FACP
Author and Disclosure Information

Kathryn Teng, MD, FACP
Department of Internal Medicine, and Director, Clinical Integration of Personalized Healthcare, Executive Board Office, Cleveland Clinic; Assistant Professor, Cleveland Clinic Lerner College of Medicine of Case Western Reserve University, Cleveland, OH

Address: Kathryn Teng, MD, FACP, Department of Internal Medicine, G10, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195; tengk@ccf.org

ABSTRACTMany young women with anorexia nervosa develop premenopausal osteoporosis. In particular, female athletes have a much higher incidence of disordered eating than their peers and therefore are at a much higher risk of stress fractures and other traumatic bone pathology. This review summarizes factors affecting the development of premenopausal osteoporosis in these patients and identifies potential targets for intervention.

KEY POINTS

  • Women gain 40% to 60% of their bone mass during adolescence, a time coinciding with the peak incidence of anorexia nervosa, and they attain their peak bone mass by the time they are in their 20s.
  • The etiology of osteoporosis in anorexia nervosa is complex and multifaceted. Early detection and treatment are critical.
  • Osteoporosis in premenopausal patients is defined as low bone mineral density (a Z score below −2.0) in combination with risk factors such as chronic malnutrition, eating disorders, hypogonadism, glucocorticoid exposure, and previous fractures.
  • Restoring body weight is the key treatment. Vitamin D should be supplemented if low. Estrogen therapy has not been shown to be effective, and exercise may be counterproductive. Bisphosphonates and teriparatide should be used with caution, if at all.

WHAT CAN WE DO FOR NOW?

  • Weight restoration and nutritional rehabilitation remain the keys to treatment of low bone density to reduce the risk of osteoporosis in patients with anorexia nervosa. However, as many as one-third of patients with anorexia nervosa relapse during their lifetime, and other treatments are needed to stabilize and prevent bone loss.
  • Vitamin D deficiency is clearly associated with a risk of osteoporosis and fracture, and patients with vitamin D deficiency should be treated with supplementation.
  • Standard therapies in postmenopausal patients (such as bisphosphonates and teriparatide) should be used with caution in premenopausal anorexia nervosa patients because of potential long-term health risks.
  • Although treatment of amenorrhea and estrogen deficiency has been shown to at least stabilize bone density in postmenopausal patients, this does not appear to be the case in premenopausal girls and young women.
  • As we learn more about hormonal factors in anorexia nervosa, we hope to identify interventions that will help restore weight and decrease the risk of osteoporosis. A summary of potential treatment strategies and targets for prevention of osteoporosis in anorexia nervosa is presented in Table 2.
     

Acknowledgment: The author thanks the General Internal Medicine Works in Progress Group for its editorial comments, and Dr. Ellen Rome for her mentorship and support.

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