Gender differences in the prevalence and severity of bone disease in thalassaemia

Abstract

Background: The pathogenesis of bone disease in thalassaemia major (TM) is multifactorial and remains unclear, although gonadal dysfunction probably has the most dominant role.

Objective: The aim of the study is to investigate the impact of several factors on the development of reduced bone mass in patients of both sexes with TM, treated in our Center.

Subjects and methods: 76 thalassaemic patients (26 males, 50 females) of Greek Cypriot origin with a mean age of 31.4 (17-53) years were included in the study. All patients were on the standard treatment protocol for thalassemia at our Center. Bone mineral density (BMD) of lumbar spine and femoral neck was measured by dual-energy X-ray absorptiometry. Factors known to be associated with low bone mass (gender, endocrine disorders, iron overload) were included in the analysis to ascertain possible associations. Iron overload calculation was based on the mean ferritin level over a 6-year period and T2* MRI of the liver and the heart. Statistical analysis was performed with the SPSS program.

Results: Bone disease was present in the spine of 89.5% of the patients and in 84.2% at the femoral site. Male patients were more frequently affected than females (92.3% vs. 88.0% in the spine and 88.5% vs. 82% at the femoral neck). Hypogonadal patients were found to be more frequently affected compared to eugonadal patients (94.1% in spine and 88.2% cyat the femoral neck compared to 89.5% and 81.6% respectively). Males with normal gonadal function were more severely affected in the lumbar spine than eugonadal women (male mean BMD z-score was -3.0 vs. -2.037 in women, p=0.004). Low BMD values were found to be more common in the presence of endocrinopathies. No correlation was found between ferritin status and severity of bone disease. Patients with severe liver iron overload seemed to be more affected in the spine. Heart T2* MRI measurements showed that patients with severe and moderate iron overload in the heart were more affected with bone disease in both the spine and femoral neck.

Conclusions: This study demonstrates a gender difference not only in the prevalence of osteoporosis/osteopenia in patients with TM, but also in the severity of the disorder, as males are more frequently and severely affected than females. Moreover, hypogonadism may have a greater impact on spine BMD in females than in males. The underlying pathogenic mechanisms contributing to the development of bone disease in thalassaemia are multiple and complicated, indicating the necessity of further investigation in order to understand the pathophysiology of this highly prevalent complication. Further research in this field will allow the design of preventive and therapeutic measures.