Bone mineral density in childhood cancer survivors (CCS).

Abstract

9157 Background: Decreased bone mineral density (BMD) has been reported in childhood cancer survivors (CCS). However, factors associated with low BMD in CCS are not well characterized. Objective: To identify factors associated with low BMD (Z-score ≤ −1) in CCS. Methods: In a cross-sectional study of CCS. BMD was determined by dual-energy x-ray absorptiometry. All patients underwent growth hormone (GH) stimulation testing. Multivariable logistic regression was utilized to evaluate relations between anthropometrics, endocrine function, and treatment history with BMD, adjusted for bone age and gender. Results: Of 284 CCS patients, 41 were excluded due to previous diagnosis of GH deficiency (GHD) and/or treatment with GH, leaving 243 subjects (54% males), median age 15.1 years (range 9.5-18.0 years), surviving 5.4-17.8 years after cancer diagnosis. 21% GHD and 0.8% had gonadal failure. 21% had low lumbar spine (L2-L4) BMD and 6% had low total body less head (TBLH) BMD. Brain irradiation (yes vs. no; Odds ratio [OR] 3.8; 95% confidence interval [CI] [1.0, 15.6]), cumulative prednisone equivalent dose (≥ 6350 vs. 0 mg; OR 4.8; CI [1.7, 14.2]), lower lean body mass (LBM) Z-score (per standard deviation (SD); OR 1.8; CI [1.2, 3.0]), and GHD status (yes vs. no; OR 2.8; CI [1.1, 6.7]) were associated with low L2-L4 BMD (adjusted for height, Tanner stage, and age). Lower LBM Z-score (per SD; OR 4.5; CI [1.9, 12.5]) and increased time since diagnosis (>10 vs. 5-10 years; OR 3.8; CI [1.1, 14.3]) were associated with low TBLH BMD (adjusted for height). Conclusions: In CCS, lower LBM, higher cumulative steroid exposure, history of brain irradiation, longer time since diagnosis, and GHD were associated with low BMD. LBM and GHD are the only modifiable risk factors for low BMD. Weight-bearing physical activities and early treatment of GHD to increase BMD are recommended in CCS. No significant financial relationships to disclose.