Anorexia nervosa (AN) is the third-most common chronic disorder diagnosed in adolescent girls in the United States. Although improved nutrition intake and weight recovery remain the goal for all patients with AN, the effect on body composition, especially regional fat distribution, may make psychological and physical recovery more difficult in a population so focused on body image.
Studies of regional fat distribution in adults with AN have shown decreased extremity fat at baseline and increased trunk fat with weight recovery, resulting in truncal adiposity. There have been several studies on this topic in adults but very few have focused on adolescents. Therefore, a recent study in the American Journal of Clinical Nutrition sought to determine body composition and regional fat distribution in adolescents with AN and measured changes in these parameters during weight recovery.
Twenty-one adolescent girls with AN and 21 control subjects matched for age and pubertal stage were included in this study. All AN subjects were enrolled in integrated treatment programs for the duration of the study. Height, weight and body composition were measured at baseline through dual-energy X-ray absorptiometry (DXA), six month and 12 month visits. Four-day food records were analyzed to assess intakes of macronutrients and micronutrients at each visit. Weight recovery was defined as a >10% increase in body mass index (BMI).
At baseline, the girls with AN had a lower percentage of trunk fat than did the control subjects, whereas the percentage of extremity fat was not significantly different between the groups. There was no significant difference between the groups for total calories, protein or carbohydrates. However, girls with AN consumed significantly less fat and saturated fat than did the controls. BMI increased by a mean of 3.5 in the 13 anorexic subjects who met the criteria for weight recovery. At 12 months, in weight-recovered AN subjects, 55.6% of the weight gain was attributable to an increase in fat mass and 44.4% was attributable to an increase in lean body mass (LBM).
In contrast to studies on adults with AN, percentage extremity and trunk fat was not significantly different in adolescent AN subjects compared with controls. Thus, weight recovery resulted in a tendency toward normalization of body composition rather than the development of central adiposity. This concept is further supported by the finding that girls with the least trunk fat at baseline gained the most trunk fat over time. Regional fat distribution at baseline and changes with weight recovery are thus very different in adolescent than in adults with AN and may be related to the duration or severity of hypercortisolemia in adolescents compared with adults. These results are important in that they will allow healthcare providers to convey to adolescents with AN that weight recovery is not likely to lead to central adiposity.
Madhusmita Misra, Leslie A. Soyka, Karen K. Miller, et al., Regional body composition in adolescents with anorexia nervosa and changes with weight recovery, Am J Clin Nutr 77: 1361-1367 (June 2003) [Reprints not available. Address correspondence to A Klibanski, Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, BUL 457B, 55 Fruit Street, Boston, MA 02114. E-mail: firstname.lastname@example.org]
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