Bone Abstracts

Introduction: Children and adolescents with eating disorders are at risk of reduced bone mass and bone mineral density. Indeed, 60% higher risk of fracture has been reported in childhood/adolescent eating disorders compared to healthy controls. However, few longitudinal studies have been carried out to examine size adjusted changes in bone health over time, and the relationship with anthropometry and growth.

Methods: A retrospective audit of 25 female eating disorder patients who had attended a paediatric DXA service on two occasions(baseline and follow-up) was carried out. Each patient had received total body (TB), lumbar spine (LS) scans and 15 patients had a lateral spine for vertebral fracture assessment (VFA). TB results were converted to percent predicted BMC for bone area (BA) LS DXA results were adjusted using BMAD as recommended by the ISCD. Measurements of lean mass (LM) and fat mass (FM) were derived from the TB DXA scan, and height, weight and BMI SDS were calculated using the 1990 British Growth Reference data.

Results: Mean age at baseline was 14.3(11.1–17.1) years and 16.3(12.1–19.8) years at follow-up. Bone area (BA) increased at TB from 1760(1288–2285) cm² at baseline to 1875(1510–2321) cm² at follow-up (P<0.001), and LS BA increased from 36.3(28.1–44.2) cm² at baseline to 37.7(31.8–47.2) cm² at follow-up (P=0.002). TB percent predicted BMC for BA decreased from 98.2(89–108)% to 95.9(88–111) at follow-up (P=0.029). LS BMAD SDS decreased from −1.2 (−2.6 to 0.3) at baseline to −1.3(−3.0 to −0.3) at follow-up (P=0.041). Height SDS was −0.2 (−2.2 to 1.2) at baseline and −0.5 (−3.8 to 1.1) at follow-up. There was no correlation between change in any of the bone parameters and change in any of the body composition parameters. However, there was a positive correlation=0.507 (P=0.012) between change in height SDS and change in LS BMAD. No vertebral fractures were reported in this patient group.

Conclusion: While bone size increased in childhood/adolescent eating disorder, size adjusted bone density decreased. This decrease was not associated with change in weight, LM, FM or BMI, but was associated with change in height SDS. Faltering growth in this patient group is likely to be a risk factor for low bone mass, hence potential increase in fracture risk.

Disclosure: The authors declared no competing interests.