Bone mineral density in children with sickle cell anemia

Abstract

We evaluated bone mineral density (BMD) and risk factors for poor bone mineralization in children with sickle cell anemia (SCA). Twenty-five children with severe manifestations of SCA (frequent hospitalizations, growth delay, or need for chronic red cell transfusions) were enrolled. Bone density was assessed at lumbar spine and proximal femur with dual-energy X-ray absorptiometry (DXA), and Z-scores were calculated by comparison with age, sex, and ethnicity-specific reference data. The median age of the study population was 12.8 years (10.2-19.8 years). Calcium intake was inadequate in 60%, and serum 25-hydroxy vitamin D (25-OHD) level <50 nM in 74% of patients. Median Z-scores for lumbar spine (-2.3) and proximal femur (-1.7) were markedly reduced, and 64% (95% confidence interval, 43%-82%) of patients had low bone density. Z-scores were not related to age, growth delay, chronic transfusions, or ferritin level. Our results suggest that children with severe manifestations of SCA have low BMD, and possess significant deficits in dietary calcium and circulating vitamin D.