Study finds serious bone loss in 90 percent of women with anorexia

Estrogen supplements do not appear to prevent bone loss in anorexia

More than 90 percent of young women with anorexia nervosa were found to have significant bone loss in a study conducted at Massachusetts General Hospital (MGH). The report, appearing in the November 21 issue of Annals of Internal Medicine, also found that taking estrogen did not seem to reduce the risk of bone loss.

"While it is well known that bone loss is a significant problem for women with anorexia, this study shows how extensive the problem is and characterizes factors that predict bone loss," says Steven Grinspoon, MD, the paper's lead author, who is on the staff of the MGH Neuroendocrine Unit. "It also shows that regaining and maintaining a healthy weight is key to preventing or reducing bone loss."

David Herzog, MD, director of the MGH Eating Disorders Clinic and a study co-author, adds, "Anorexia and its associated bone loss are very serious medical problems that present difficult challenges to both patients and the clinicians who care for them. We hope one result of this study will be to help motivate women with anorexia to get the treatment they need."

Patients with anorexia nervosa - an extreme loss of weight associated with seriously restricting food intake, an unrealistic fear of weight gain and a distorted body image - are at risk for a number of serious, even life-threatening health problems. A loss of menstrual periods, associated with disruption of normal levels of estrogen and other hormones, is a hallmark of anorexia in women. Loss of bone mass, sometimes leading to fractures, is a significant complication in most women with anorexia, but it was not previously known whether that bone loss resulted primarily from the estrogen deficiency or from overall malnutrition.

The study enrolled 130 women in their mid-20s with anorexia nervosa, most of whom did not have normal menstrual periods. Some participants had resumed periods while taking supplemental estrogen, primarily in the form of birth control pills. Participants all were living in their communities, not hospitalized for treatment of their illness. The research team gathered detailed histories and measurements on the participants - including menstrual history, estrogen use history, fracture history and frame size - before conducting bone density measurements of the spine and hip.

The results showed that 92 percent of study participants had significant bone loss (osteopenia) in at least one of the sites measured, and 38 percent of participants had bone loss serious enough to meet World Health Organization criteria for osteoporosis. Broken down by site of measurement, more than 50 percent of the women had osteopenia at the spine and almost 25 percent had osteoporosis; and 47 percent had osteopenia measured at the hip with 16 percent having osteoporosis.

Of numerous other variables recorded, weight was the most powerful predictor of bone loss at all sites, with those women who weighed the least showing the most serious bone loss. Menstrual history also correlated with spinal bone density, suggesting that estrogen deficiency plays a greater relative role in spinal bone loss than in loss at other sites. Current estrogen use was reported in 23 percent of participants and previous estrogen use reported in 58 percent of participants. However, estrogen use had no effect on bone density at any of the sites measured. Use of calcium or Vitamin D supplements similarly had no effect.

Anne Klibanski, MD, director of the MGH Neuroendocrine Unit and the study's principal investigator, says, "Some of these young women are experiencing bone loss comparable to that of women many decades older, despite estrogen therapy. Given this severity and the prevalence of bone loss, the importance of screening all women with anorexia for osteoporosis cannot be over-emphasized. Other studies have shown that some degree of bone loss in anorexia may be permanent, so it will be critical to develop new therapies to prevent and treat bone loss in these women."

The study's other co-authors are Elizabeth Thomas, NP, Sarah Pitts, Erin Gross, and Karen Miller, MD, of the MGH Neuroendocrine Unit and Diane Mickley, MD, of the Wilkins Center for Eating Disorders in Greenwich, Conn. The research was supported by grants from the National Institutes of Health, the Rubenstein Foundation and the Harvard Eating Disorders Center.