Bone Abstracts

Introduction: Osteopenia is a well-known complication of anorexia nervosa (AN) in older adolescents and adults, especially in those with a long duration of the disease and a severe underweight.

Aim: We investigated whether young premenarchal girls with AN have similar risk factors for a disturbed bone growth and mineralization.

Methods: Twenty-four female premenarchal AN patients as well as 24 age and height matched female controls underwent a peripheral quantitative computed tomography (pQCT) scan at the distal radius of the non-dominant arm.

Results: The age of the AN subjects ranged between 11.8 and 18.5 years. Mean (±S.D.) weight loss was 22.3±9.3%, which occurred during the preceding 7.8±3.9 months. Mean weight Z-score (−2.19±1.40 vs 0.15±0.90; P<0.0001) as well as mean BMI Z-score (−2.28±1.09 vs 0.07±0.83; P<0.0001) was significantly lower in AN patients, whereas height Z-score (−0.36±1.02 vs 0.23±1.02; P=0.1) was comparable at the moment of examination. AN patients had a significantly lower mean total bone cross-sectional area (CSA) (294.9±31.5 vs 334.1±54.4 mm²; P=0.004) and periosteal circumference (60.8±3.2 vs 64.6±5.0 mm; P=0.003) in comparison with the control subjects. Trabecular bone mineral density (186.1±32.2 vs 203.5±30.9 mg/cm³; P=0.06) and bone strength index (30.1±9.0 vs 34.6±10.5 mg/mm4; P=0.1) were also lower, but at borderline significance. Total bone CSA Z-score correlated with duration of the weight loss (r=0.43; P=0.03), but not with the age and BMI Z-score at diagnosis and the severity of the weight loss was found. None of the other bone parameters correlated with any of the disease related factors.

Conclusion: In female premenarchal AN patients the rapidity but not the severity of the weight loss before diagnosis affects the periosteal bone apposition, which is more disturbed than the bone mineralization at the distal bone end of radius.