Estrogen therapy increases bone mass in girls with anorexia nervosa
MedWire News: Estrogen replacement therapy, given at physiologic doses, improves bone accrual rates in adolescent girls with anorexia nervosa (AN), US study data show.
The findings, presented by Madhusmita Misra (Harvard Medical School, Boston, Massachusetts, USA) at The Endocrine Society's 93rd Annual Meeting in Boston, arose from an 18-month study among 110 girls with AN and 40 healthy-weight controls. All the girls were between 12 and 18 years of age, a common time for AN to start and an important time for building optimal bone mass.
Misra explained that low bone mineral density (BMD) is common in patients with AN.
Previous studies have shown that high doses of oral estrogen given as an oral contraceptive do not improve BMD in AN, but the impact of physiologic doses of oral estrogen to mimic early puberty and of transdermal estrogen (which does not suppress IGF-1) on bone accrual has not been examined, she remarked.
To investigate this strategy, the researchers randomly assigned girls with AN and mature bone (defined as closure of the growth plates; n=96) to receive either placebo or a full adult dose of estrogen (100 µg 17β-estradiol per day) given via a skin patch. Girls with AN and immature bones (n=14) received incremental low doses of oral estrogen, ranging from 3.75 to 11.25 µg of estradiol per day. These low, natural levels mimic estrogen levels seen in early puberty and avoid accelerating fusion of the growth plates, which would otherwise limit height potential, Misra explained.
The control group received no treatment other than calcium and vitamin D supplements, which was given to all participants.
The researchers found that the girls with AN who received estrogen therapy had significantly greater changes in lumbar spine and hip BMD at 6, 12, and 18 months compared with those who did not receive estrogen, even after controlling for baseline age and weight changes.
Furthermore, the girls with AN who did not receive estrogen therapy had significantly lower changes in BMD at all time points compared with controls, whereas the BMD changes in the girls who did receive estrogen were similar to those observed in the control group.
"In addition to weight gain, physiological estrogen could be a potential therapeutic option for optimizing bone mass in girls with anorexia nervosa," Misra concluded.
MedWire (www.medwire-news.md) is an independent clinical news service provided by Springer Healthcare Limited. © Springer Healthcare Ltd; 2011
By Laura Dean