Body Fat and Outcome in Anorexia Nervosa

Reprinted from Eating Disorders Review
July/August 2007 Volume 18, Number 4
©2007 Gürze Books

Because as many as half of anorexia nervosa (AN) patients have relapses, identifying possible factors that might help predict relapse might help clinicians develop better treatment interventions for patients. In what is believed to be the first study to examine body composition as a predictor of relapse among AN patients, Dr. Laurel E. S. Mayer and co-workers at Columbia University tested body composition and fasting cortisol and leptin levels among weight-recovered women with AN before the women were randomly assigned to treatment (Am J Psychiatry 2007;164:970). The women were participants in the Fluoxetine to Prevent Relapse in Women with Anorexia Nervosa trial (New York site) and in the Energy Homeostasis in Anorexia Nervosa Study, a longitudinal trial involving changes in body composition. Thirty-two of the 45 women in the relapse-prevention trial were participants in both studies.

The women, who were between 18 and 45 years of age, received inpatient treatment and their weights were normalized to at least 90% of their ideal body weight. They were then studied after maintaining this weight for 2 to 4 weeks but before random assignment in the relapse-prevention trial. The researchers used fasting morning blood sampling and body composition assessment with anthropometry and dual-energy x-ray absorptiometry. At the end of the study, clinical outcome was determined using modified Morgan-Russell criteria (full, good, fair, poor). These results were then dichotomized into treatment “success” or “failure.”

Body fat differences were significant

There were no significant differences between the success and failure groups on body mass index (BMI) or percent of lifetime BMI, nor were there significant differences in serum cortisol or serum leptin levels. However, the percentage of body fat was significantly different between the groups (P=< 0.007). The authors reported that a lower percentage of body fat was associated with poorer long-term outcome.

The authors note that the results of this study are provocative. While Dr. Mayer and her colleagues feel that it would be premature to recommend that standard clinical care include body composition testing after weight recovery, increased body fat may serve to protect AN patients against relapse.

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