Bone mineral density in patients with thalassaemia major in the UK

P. Tzoulis; A. Ang; F. Shah; M. Barnard

Introduction: Osteoporosis is a major cause of morbidity in β thalassaemia major patients. Our institution serves one of UK’s largest populations of thalassaemia patients. This study aimed to examine the prevalence of osteopenia and osteoporosis in thalassaemia major patients and identify risk factors for low bone mineral density (BMD).

Methods: BMD of lumbar spine and neck of femur were measured using dual-emission X-ray absorptiometry (DEXA). Osteopenia was defined as Z score between −1.5 and −2.5 and osteoporosis as <−2.5.

Age, gender, smoking, hepatitis C infection, compliance with chelation therapy, mean ferritin over 10 years, highest Ferriscan liver iron concentration from 2008 to 2010, highest liver iron concentration as estimated by T2* and lowest cardiac MR T2* value from 1999 to 2010, endocrinopathies, glycaemic status and vitamin D status were tested for associations with osteopenia and osteoporosis, using univariate analysis.

Results: Ninety-nine patients, 49 males and 50 females, with mean age 36±9 years were included. 68.7% of patients had hypogonadism, 14.7% hypothyroidism and 13.7% hypoparathyroidism. 40.9% of patients had diabetes and 16.1% impaired glucose regulation. Lumbar spine BMD suggested that 22.4% had osteoporosis, 48.0% osteopenia and 29.6% normal BMD. Median Z score was −1.9 (range 0.9 to −5.0). Neck of femur BMD demonstrated that 13.3% had osteoporosis, 40.8% osteopenia and 45.9% normal BMD. Median Z score was −1.5 (range 0.8 to −3.7).

Parameters with P-values <0.05 on univariate analyses for associations with osteoporosis/osteopenia are presented in the table. On multivariate analysis, the only statistically significant association was between hypogonadism and spine low BMD (P value =0.048).

Conclusions: Most β thalassaemia major patients have low BMD. Hypogonadism was an independent risk factor for reduced BMD in spine. Prevention of hypogonadism by effective iron chelation and hormone replacement therapy may help to prevent osteopenia/osteoporosis.

Table 1
Type of abnormality in BMD	Parameter	P-value
Spine low BMD	Low cardiac T2* (1999–2010)	0.038
Hypogonadism	0.009
Diabetes mellitus/ impaired glucose regulation	0.047
Hip low BMD	Female gender	0.005
Low Ferriscan® LIC (2008–2010)	0.019
Hypothyroidism	0.018
Diabetes mellitus/ impaired glucose regulation	0.040

Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.

Funding: This research did not receive any specific grant from any funding agency in the public, commercial or not-for-profit sector.

Endocrine Abstracts

P147