Bone mineral density and bone turnover in adolescent girls with anorexia nervosa: a 3-year retrospective cohort study.

BACKGROUND

Adolescent girls with anorexia nervosa (AN) are at high risk of reduced bone mineral density (BMD) due to chronic malnutrition, hypogonadism, and endocrine disturbances. Longitudinal studies integrating densitometric, hormonal, and biochemical markers in this population remain limited.

OBJECTIVE

To retrospectively evaluate bone metabolism in adolescent girls with AN over a three-year period, including assessment of BMD, bone turnover markers, and hormonal and biochemical parameters.

METHODS

Thirty-six adolescent girls with AN were followed for up to three years. Lumbar spine BMD (Z-score) was measured annually by DXA. Bone turnover markers (osteocalcin, CTX), hormonal parameters (estradiol, IGF-1, LH, FSH, cortisol, PTH), and calcium metabolism were assessed. Associations with clinical characteristics and treatment status were analyzed.

RESULTS

The greatest BMD loss occurred during the first 12-24 months of illness, with partial recovery at 36 months. Hormonal therapy combined with calcium and vitamin D supplementation was associated with a more favorable BMD trajectory. Higher BMI (used in correlation analyses) was associated with more favorable hormonal profiles (including IGF-1, estradiol and LH), but not with changes in BMD Z-scores. These findings suggest that early skeletal changes may lag behind endocrine recovery during weight restoration. Bone formation markers increased, while bone resorption markers declined. Higher baseline calcium parameters were associated with changes in BMD, potentially reflecting bone resorption.

CONCLUSIONS

Bone recovery in adolescent girls with AN depends not only on weight restoration but also on normalization of endocrine function. The effect of nutritional rehabilitation on bone appears to be mediated through hormonal recovery, while skeletal improvement may lag behind. Monitoring bone turnover markers and calcium homeostasis may provide additional clinical insight.