Bone metabolism in adolescent boys with anorexia nervosa.
BACKGROUND
Anorexia nervosa (AN) is a condition of severe undernutrition associated with low bone mineral density (BMD) in adolescent females with this disorder. Although primarily a disease in females, AN is increasingly being recognized in males. However, there are few or no data regarding BMD, bone turnover markers or their predictors in adolescent AN boys.


OBJECTIVE
We hypothesized that BMD would be low in adolescent boys with AN compared with controls associated with a decrease in bone turnover markers, and that the gonadal steroids, testosterone and estradiol, and levels of IGF-I and the appetite regulatory hormones leptin, ghrelin, and peptide YY would predict BMD and bone turnover markers.


METHODS
We assessed BMD using dual-energy x-ray absorptiometry and measured fasting testosterone, estradiol, IGF-I, leptin, ghrelin, and peptide YY and a bone formation (aminoterminal propeptide of type 1 procollagen) and bone resorption (N-telopeptide of type 1 collagen) marker in 17 AN boys and 17 controls 12-19 yr old.


RESULTS
Boys with AN had lower BMD and corresponding Z-scores at the spine, hip, femoral neck, trochanter, intertrochanteric region, and whole body, compared with controls. Height-adjusted measures (lumbar bone mineral apparent density and whole body bone mineral content/height) were also lower. Bone formation and resorption markers were reduced in AN, indicating decreased bone turnover. Testosterone and lean mass predicted BMD. IGF-I was an important predictor of bone turnover markers.


CONCLUSIONS
AN boys have low BMD at multiple sites associated with decreased bone turnover markers at a time when bone mass accrual is critical for attainment of peak bone mass.
BUL 457, Neuroendocrine Unit, Massachusetts General Hospital, 55 Fruit Street, Boston, Massachusetts 02114, USA. mmisra@partners.org
Madhusmita
M
Misra
Debra K
DK
Katzman
Jennalee
J
Cord
Stephanie J
SJ
Manning
Nara
N
Mendes
David B
DB
Herzog
Karen K
KK
Miller
Anne
A
Klibanski
D015502:Absorptiometry, Photon; D000293:Adolescent; D000856:Anorexia Nervosa / Q000378:metabolism*; D001823:Body Composition; D015992:Body Mass Index; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D006801:Humans; D007334:Insulin-Like Growth Factor I / Q000032:analysis; D008297:Male; D010446:Peptide Fragments / Q000097:blood; D019894:Peptide YY / Q000097:blood; D011347:Procollagen / Q000097:blood
D010446:Peptide Fragments; D011347:Procollagen; C047202:procollagen Type I N-terminal peptide; D019894:Peptide YY; D007334:Insulin-Like Growth Factor I