Background: The SNAP study is a prospective fracture study of children with chronic inflammatory and/or disabling conditions.
Objective and Hypotheses: The overall aim of the study is to establish if there is a causal link between measured body-size related bone density and low trauma fracture.
Method: 280 children, aged 518 years, from seven disease groups namely; acute lymphoblastic leukaemia (ALL), rheumatological disease, inflammatory bowel disease, cystic fibrosis, coeliac disease, Duchenne muscular dystrophy (DMD), and cerebral palsy, were recruited. At baseline, bone density by DXA (lumbar spine and total body less head (TBLH)) and pQCT (radius), spinal radiographs, muscle strength, fracture, and medical history were assessed.
Results: Fifty-one children (18%) had a history of long bone fracture of either the upper (n=32) or lower limb (n=19). Spinal radiographs identified 52 children with vertebral height loss, of which the incidence was highest for children with ALL (12/30) and DMD (14/40) (P<0.001). Steroid exposure was reported in 65% of the children and back pain was reported in 37%. Although the highest levels of steroid exposure and the greatest incidence of back pain were reported for ALL and DMD, no significant statistical differences were reported between the groups. Bone density z-scores were significantly lower than 0 for L2L4BMAD, TBLH BMD, trabecular BMD, and strength strain index (SSI), but failed to discriminate between children with and without long bone fractures. Similarly, L2L4BMAD and SSI z-scores were not significantly different for children with vertebral or without vertebral fractures. However, trabecular bone density at the radius was significantly reduced, z=−1.2 (1.1) and −0.5 (1.3 P<0.001) for those with and without vertebral fractures respectively.
Conclusion: In conclusion, disease and steroid exposure have significant impact on the identification of individuals at risk of vertebral fracture. However, the greatest odds ratio for vertebral fracture was low bone density as measured by pQCT. Evidence of the predictive power of these measurements will only be confirmed with future follow-up of this group.
18 Sep 2014 - 20 Sep 2014