Bone Abstracts

Background: Anorexia nervosa (AN) presenting in childhood can have devastating implications for growth, puberty, menstruation and bone health. It may lead to altered bone structure and inadequate acquisition of bone mass with increased risk of fracture.

Objective: To describe growth, pubertal and bone mineral density data in a cohort of adolescents with AN managed in a tertiary metabolic bone service.

Methods: 62 adolescent females with AN assessed between 2009 and 2014 underwent assessment of pubertal status, menstrual history, auxology and bone mineral density measured by DXA, QCT and pQCT. Size adjusted lumbar spine BMD (LS BMAD), LS volumetric (v) trabecular BMD (LS vTBMD), femoral neck BMD (FN BMAD), distal radial total & trabecular vBMD were measured at initial assessment.

Results: At presentation, the mean age was 16 years (1.45 S.D.). Seven had prepubertal onset of AN, 14 pubertal and 41 postpubertal. 25 were inpatient, 32% had back pain and one had experienced a metatarsal fracture from repetitive exercising. 42 presented with secondary amenorrhoea (mean duration 20 months, range 5–60). Mean BMISDS was −1.48 (−5.61–1.26). Baseline bone density z-scores are given in the table 1:

LS BMAD z-score was ≤−2.00 (−2.00 to −2.90) in 13 patients, whereas LS vTBMD z-score ≤−2.00 (−2.04 to −4.18) in 29 patients. One had mild grade 1 vertebral endplate fractures of T₄, T₅ and T₇ on DXA vertebral fracture assessment. LS vTBMD was correlated with oestradiol concentrations and was significantly lower in those with oestradiol <120 pmol/l (−2.18 vs −1.70, P<0.05).

Conclusion: Adolescent girls with AN have reduced size adjusted BMD for age at the lumbar spine. The marked decline in LS vTBMD, possibly due to relative hypercortisolaemia (Misra, Lancet Diabetes Endocrinology 2014) may increase the risk of sustaining atraumatic vertebral fractures.

Disclosure: The authors declared no competing interests.