Misra M et al. (2008) Bone metabolism in adolescent boys with anorexia nervosa. J Clin Endocrinol Metab 93: 3029–3036

Anorexia nervosa is becoming increasingly recognized in boys. BMD is reduced in girls and women with this disorder but controlled studies of this effect in boys are lacking. Misra and colleagues compared BMD measurements in 17 adolescent boys (aged 12–19 years) undergoing treatment for anorexia nervosa and in 17 healthy controls matched for chronological and bone age.

BMD was assessed by dual X-ray absorptiometry at the lumbar spine, hip, femoral neck, trochanter, intertrochanteric region and for the whole body. Values were adjusted for height because this technique underestimates BMD in short individuals and overestimates it in tall ones. Misra and colleagues also measured various markers, including insulin-like growth factor I, testosterone, estradiol, ghrelin, peptide YY and leptin, procollagen type I N-terminal propeptide (for bone formation) and N-telopeptide (for bone resorption).

Anorexic boys were hypogonadal and had reduced bone turnover. Height-adjusted and absolute BMD was lower at all sites in boys with anorexia of any duration than in controls. Testosterone and estradiol levels were lower and peptide YY levels higher in anorexic boys than in controls. The most important predictors of BMD were testosterone, lean mass, BMI and bone age. Insulin-like growth factor I levels predicted levels of bone turnover markers.

These findings indicate that adolescent boys with anorexia nervosa are at risk of not achieving their optimum peak bone mass and that several markers can predict low BMD.