Bone metabolism in anorexia nervosa

Abstract

Anorexia nervosa (AN), a psychiatric disorder predominantly affecting young women, is characterized by self-imposed, chronic nutritional deprivation and distorted body image. AN is associated with a number of medical comorbidities including low bone mass. The low bone mass in AN is due to an uncoupling of bone formation and bone resorption, which is the result of hormonal adaptations aimed at decreasing energy expenditure during periods of low energy intake. Importantly, the low bone mass in AN is associated with a significant risk of fractures and therefore treatments to prevent bone loss are critical. In this review, we discuss the hormonal determinants of low bone mass in AN and treatments that have been investigated in this population.

Figure 1

Physiologic estrogen replacement increases bone density in adolescent girls with anorexia nervosa. Percent change in lumbar spine bone mineral density (LBMD) in adolescent girls with anorexia nervosa (AN) randomized to placebo (AN E–; black bars), girls with AN randomized to estrogen (AN E+; gray bars), and normal-weight control girls (C; white bars). AN E+ girls had significant increases in LBMD at 6, 12, and 18 months compared with AN E– girls. When compared with control girls, AN E– girls had significant decreases in LBMD at 6, 12, and 18 months, whereas AN E+ girls did not differ from control girls for changes in BMD over time. Analysis was performed for differences between means for pairs. *p < 0.05. Borrowed with permission from [49] © 2011, John Wiley and Sons.