E63 Prevalence and risk factors of low bone mineral density and fractures in children with beta-thalassemia

Abstract

Abstract Background Declining bone mineral density can affect children and lead to an increased risk of fractures. Moreover, it is an important cause of morbidity and mortality in people with beta-thalassemia. However, the prevalence of osteoporosis and bone fractures in a young population with beta-thalassemia remains uncertain. Objective To investigate the prevalences of low bone density and fractures among beta-thalassemia young patients (homozygous form) and to identify clinical and laboratory factors that are associated with these conditions. Methods We collected data of all childrens with beta-thalassemia who were followed up in the hematologic clinic. They were screened to measure bone mineral density (BMD) using the dual energy X-ray absorptiometry (DXA). A retrospective chart review was performed to report the lifetime prevalence of bone fractures and clinical associations with patient data. Results We examined 67 young patients with beta-thalassemia, 6–16 years old (median: 12 years). Low BMD was found in 10.8% (spine) and 32% (total body). Multiple regression analysis showed that BMD was predicted by Z-scores for height and weight at DXA. History of splenectomy was associated with lower BMD. Patients with a history of fractures had lower Z-scores for spine BMD (-2.30 vs -0.58, P = 0.01) and total-body BMD (-1.90 vs -0.87, P = 0.04) compared with those without a history of fractures. Patients with spine BMD Z-score of up to -2 SD score had significantly increased prevalence of fractures compared with those with Z-score more than -2 SD score (10 vs 5%, P = 0.02). Factors associated with lower mean BMD Z-score were history of splenectomy, vitamin D deficiency when the factors associated with bone fractures were male sex (RR 1.52, 95%CI 1.22–3.21) and haemoglobin level below 7 g/dl (RR 1.76, 95%CI 1.31–4.22). Conclusion This study provides information on risk factors for low BMD in pediatric beta-thalassemia. The results reveal the association between low BMD and a history of splenectomy and vitamin D deficiency, and the relationship between bone fractures in boys especially with low BMD.