LAUSR

Background Cystic fibrosis (CF) is a multi-system disease resulting from mutations in the CFTR gene. CF patients are at risk of developing osteopenia. Regular monitoring of bone mineral density (BMD) is currently recommended in the standards of care for CF. Aims To explore the extent of low BMD in children with CF and identify risk factors associated with decreased BMD. Establish the rate of decline in BMD to inform future practice. Methods All children undergo routine DEXA scan at bi-annual assessments from 8 years of age. A single centre retrospective review of CF Registry records and online hospital records was conducted for children born 2000–2006. Z-score values were obtained for BMD and BMI as well as FEV1%/FVC% predicted (GLI), and possible confounding factors were also recorded. Abstract P8 Table 1 DEXA sequence Scan 1 Scan 2 Scan 3 Scan 4 ANOVA sig. Number 96 87 60 18 Age in years (Mean,SD) 9.98 (1.9) 11.79 (1.8) 13.24 (1.5) 14.34 (1.5) M/F 37/59 33/54 25/35 8/10 L1-L4 −0.12 −0.37 −0.42 −0.96 0.008 L2 −0.27 −0.48 −0.59 −1.13 0.013 FEV1% 86% 83% 80% 78% 0.174 BMI Z-Score −0.03 −0.05 0.04 0.18 0.844 Vit-D 72 69 71 78 0.577 Results 96 children (59 female) had a first DEXA scan at a mean age of 10 (±1.94 years). 262 DEXA scans were performed with a median of 2 per individual. Thirteen (13.5%) had an abnormal DEXA scan over the course of the study; only 2 of these were age <10 years (n=48 performed in this age range). Risk factors for abnormal BMD (z-score ≤−2) were: a BMI z-score ≤2;>50 days of intravenous antibiotics in the year before the scan; and FEV1%<50. The table shows mean results for sequential scans; rate of decline was unpredictable. The mean change per year was −0.1 z-scores (SD=±0.5). Neither Vit D levels nor the CF-related diabetes was related to baseline or changes in BMD. Conclusion Low lung function and BMI z-scores were the greatest indicators of being at risk of osteopaenia for the cohort. With a rate of decline of only 0.1 z-score per annum the frequency of DEXA scans could be decreased in low risk children.