Weight gain and restoration of menses as predictors of bone mineral density change in adolescent girls with anorexia nervosa-1.
BACKGROUND
Adolescents with anorexia nervosa (AN) have low bone mineral density. However, the effect of disease recovery, first, on bone density measures assessed using the Molgaard approach, which differentiates between reported low bone density resulting from short bones (based on height Z-scores) and that resulting from thin bones [based on measures of bone area (BA) for height] or light bones [based on measures of bone mineral content (BMC) for BA]; and second, on height-adjusted bone density measures, has not been well characterized. We hypothesized that menstrual recovery and weight gain (> or =10% increase in body mass index) would predict an increase in these measures of bone density.


METHODS
In a prospective observational study, lumbar and whole-body (WB) bone density was measured at 0, 6, and 12 months in 34 AN girls aged 12-18 yr and 33 controls. Using Ward's modification of the Molgaard approach, we determined measures of BMC for BA and BA for height at the lumbar spine and WB and also determined spine bone mineral apparent density and WB BMC adjusted for height.


RESULTS
Girls with AN had lower spine BMC for BA Z-scores (P = 0.0009), and lower WB BA for height Z (P < 0.0001), compared with controls. Menstrual recovery and weight gain in AN (AN-recovered) (median 9 months) resulted in a stabilization of BMD measures, whereas BMD continued to decrease in AN who did not gain weight and recover menses (AN-not recovered). AN-recovered also predicted greater increases in spine BMC for BA and WB BA for height, compared with AN-not recovered (P < 0.05).


CONCLUSIONS
Even short-term weight gain with menstrual recovery is associated with a stabilization of BMD measures.
Misra
Madhusmita
M
Neuroendocrine Unit, Massachusetts General Hospital and Harvard Medical School, 55 Fruit Street, Boston, Massachusetts 02114, USA. mmisra@partners.org
Prabhakaran
Rajani
R
Miller
Karen K
KK
Goldstein
Mark A
MA
Mickley
Diane
D
Clauss
Laura
L
Lockhart
Patrice
P
Cord
Jennalee
J
Herzog
David B
DB
Katzman
Debra K
DK
Klibanski
Anne
A
D015502:Absorptiometry, Photon; D000293:Adolescent; D000856:Anorexia Nervosa / Q000378:metabolism*; D001827:Body Height; D015519:Bone Density; D002648:Child; D005260:Female; D005500:Follow-Up Studies; D006801:Humans; D008598:Menstruation; D011446:Prospective Studies; D015430:Weight Gain