Predictors of bone mineral density reduction in adolescents with anorexia nervosa.
OBJECTIVE
To determine which variables are associated with a significant reduction in bone mineral density (BMD) in adolescent anorexia nervosa and to establish guidelines for indication of bone densitometry.


METHODS
One hundred seventy patients (treated from 1997 until 1999), aged 10 to 17 years, with a DSM-IV diagnosis of anorexia nervosa were evaluated by dual-energy-x-ray absorptiometry in the lumbar spine (L2-L4) and the femoral neck. The results were compared with the normative data for BMD values by age and sex in Spanish adolescents.


RESULTS
44.1% of patients had osteopenia at the lumbar spine and 24.7% at the femoral neck. The following variables were related to osteopenia: more than 12 months since onset of the disorder (p < .001), more than 6 months of amenorrhea (p < .001), body mass index <15 (p < .001), calcium intake <600 mg/day (p < .01), and <3 hours/week of physical activity (p < .001). In a stepwise logistic regression analysis to predict reduced spinal BMD, 3 variables-months elapsed since the onset of weight loss, calcium intake, and body mass index--correctly classified 78.8% of patients.


CONCLUSIONS
Adolescent anorexia nervosa patients with the characteristics outlined above are at high risk of reduced BMD, and densitometry is recommended to determine the degree of osteopenia.
Castro
J
J
Section of Child and Adolescent Psychiatry, Institute of Psychiatry and Psychology, Hospital Clínic Universitari, Barcelona, Spain. 16812jcf@comb.es
Lázaro
L
L
Pons
F
F
Halperin
I
I
Toro
J
J
D015502:Absorptiometry, Photon; D000293:Adolescent; D000367:Age Factors; D000568:Amenorrhea / Q000209:etiology; D000856:Anorexia Nervosa / Q000150:complications* / Q000378:metabolism / Q000503:physiopathology; D015992:Body Mass Index; D015519:Bone Density; D002118:Calcium / Q000378:metabolism*; D002648:Child; D018450:Disease Progression; D015444:Exercise; D005215:Fasting / Q000009:adverse effects; D005260:Female; D005272:Femur Neck / Q000000981:diagnostic imaging; D006801:Humans; D016015:Logistic Models; D008159:Lumbar Vertebrae / Q000000981:diagnostic imaging; D010024:Osteoporosis / Q000175:diagnosis* / Q000209:etiology; D011379:Prognosis; D012494:Sampling Studies
D002118:Calcium