Among women recovering from anorexia, weight gain and resumption of menstruation are both important for reversing the loss of bone density that occurs with anorexia, a new study indicates.

Patients with active anorexia nervosa not only lose a lot of weight but they also stop having periods, they lose bone mineral density (BMD) at an average rate of 2.6 percent per year, Dr. Karen K. Miller and her co-investigators explain in the Journal of Clinical Endocrinology and Metabolism.

They point out that little is known about the factors that influence bone recovery in anorexic patients, so they followed 75 women with anorexia and measured their BMD on two occasions roughly 13 months apart.

Overall, women who resumed menstruation and gained weight had an annual increase in bone density of 3.1 percent in the spine and 1.8 percent at the hip, according to the report.

Resumption of menstrual function was associated with an increase in BMD at the spine but not the hip, with or without weight gain. Conversely, weight gain was associated with an increase in BMD at the hip but not at the spine, regardless of menstrual function.

Miller, from the Massachusetts General Hospital in Boston, and her associates conclude, “Improvements in reproduction function and weight, with increases in lean body mass a critical component, are both necessary for skeletal recovery in women with anorexia nervosa.”

SOURCE: Journal of Clinical Endocrinology and Metabolism, August 2006.