Session: SAT 224-247-Osteoporosis I
Poster Board SAT-244
Methods: We retrospectively analyzed data on patients with FA evaluated in the NCI’s Inherited Bone Marrow Failure Syndromes Study. BMD was measured by dual-energy X-ray absorptiometry scan (Hologic) at the lumbar spine and femoral neck. Data were re-interpreted after adjusting for height. We calculated height-adjusted BMD Z-scores (HAZ) in children (≤20 years) using the online Bone Mineral Density Childhood Study calculator (3). In adults, bone mineral apparent density (BMaD) Z-scores were calculated to adjust for the effect of stature on bone size and BMD (4).
Results: Data from 24 patients (8 male): 9 children (median age 11.9y; 8.1-18.4) and 15 adults (median age 31.8y; 20.6-56.6) were analyzed. FA was diagnosed by chromosomal breakage study and confirmed by complementation studies and/or mutation analysis. Seven patients (4 adults) had undergone hematopoietic cell transplantation (HCT) with a median duration of 9.1y (6.7-17.4) since transplant. Several patients were on medications known to affect BMD including androgens (4/24), glucocorticoids (1/24), estrogens (4/11 women, 1 child) and bisphosphonates (4/24). In children, mean height Z-score was -1.25 (SD 1); mean BMD Z-score at the lumbar spine was -0.52 (SD 1.4); mean HAZ was 0.58 (SD 0.8). At the femoral neck mean BMD Z-score was -1.49 (SD 0.8); mean HAZ was -0.68 (SD 1.2). In the adults, mean height Z-score was -1.55 (SD 1.4); mean BMD Z-score was -1.52 (SD 1.3) at the lumbar spine and -1.22 (SD 1.3) at the femoral neck. BMaD Z-scores were -0.78 (SD 1.5) and -0.83 (SD 1.1) respectively. Excluding patients on bisphosphonates and using cut-offs established by Melton et al. (4), for BMD values that define osteoporosis in the adults, 3/12 met criteria for osteoporosis either at the spine or femoral neck. Using cutoffs based on BMaD values instead, only 1/12 met criteria for osteoporosis.
Conclusions: Children with FA have normal HAZ consistent with previous reports. While adults tend to have lower BMD, fewer patients meet criteria for osteoporosis using BMaD. Correction for height must be considered in the interpretation of BMD in FA patients. Further study is needed on fracture risk and the effect of HCT on BMD in this population.
Nothing to Disclose: RK, NG, MBL, NS, JR, BPA, CAS
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