THE EFFECTS OF ESTROGEN ADMINISTRATION ON TRABECULAR BONE LOSS IN YOUNG-WOMEN WITH ANOREXIA-NERVOSA

To study the effects of prolonged anorexia nervosa on bone density (BD ) and to determine whether estrogen administration prevents bone loss in women with this disorder, 48 amenorrheic women with anorexia nervos a (mean age, 23.7 yr) were randomized to receive estrogen and progesti n replacement (n = 22) or no replacement (n = 26). Clinical variables, biochemical indices, and spinal trabecular BD were measured every 6 m onths for a mean of 1.5 yr. Initial mean BD (130 +/- 27 mg K2HPO4/cm(3 ), +/- 1 so) was significantly (P < 0.001) less than normal (176 +/- 2 6 mg K2HPO4/cm(3)) and less than 2 SD below normal in 21 of the 48 wom en. Forty-four women completed the study (19 in the estrogen group and 25 in the control group). The mean duration of follow-up was comparab le in the estrogen-treated (1.57 +/- 0.89 yr) us. the control group (1 .41 +/- 0.69 yr). The estrogen-treated group had no significant change in BD compared with the control group; however, there was a 4.0% incr ease in mean BD in patients with an initial ideal body weight of less than 70% who were treated with estrogen. In contrast, control patients with comparably low initial weight had a 20.1% decrease in BD. Women in the control group with spontaneous resumption of menses, all of who m had an initial percent ideal body weight of greater than 70%, had a 19.3% increase in bone mass. It is concluded that: 1) estrogen replace ment cannot prevent progressive osteopenia in young women with anorexi a nervosa; 2) a subset of patients may have improved BD with estrogen and progestin administration depending on initial body weight; and 3) recovery from anorexia nervosa is associated with significantly improv ed BD.