Discussion
In the general population osteoporosis is less common in men than in women, with the incidence of vertebral fractures being one sixth of that in women.
However, the sex difference was reversed in the thalassemia patients studied here, with men being both more commonly and more severely affected with low bone mass. This striking observation is difficult to explain. Clinical experience indicates that male thalassemia patients, particularly during their adolescent years, are less compliant than females with DFX therapy. The impact of this on peak bone mass, even with subsequent improvement in chelation compliance as they improve chela- tion therapy, may contribute to the sex difference in observed bone mineral density. However, we could find no significant correlation between severely low bone mass and serum ferritin levels, measured at the time of this study. In a study of 17 transfusion-dependent children with thalassemia also no apparent association between iron overload and vitamin D deficiency and bone disease was found. The most common endocrine disorder among our patients is hypogonadotrophic hypogonadism. In the general population hypogonadism is a well-recognized cause of overt osteoporosis and of asymptomatic osteopenia. Oestrogen replacement therapy for women is the most effective preventative measure against postmenopausal osteoporosis. The exact mechanism of action of oestrogen on bone, calcium and phosphorus metabolism has not been determined, but oestrogens appear primarily to inhibit osteoclastic activity and bone resorption. It is important to note that therapeutic correction of hypogonadism with appropriate HRT in these thalassemia patients has failed to protect them from low bone mass. In spite of regular blood transfusions the ineffective erythro- poiesis is not fully suppressed in thalassemia major. Expansion of the marrow may contribute to the decreased bone mineral density. It is also possible that excess iron in the bone may influence osteoblast number and activity and lead to the development of osteoporosis.
In the general population, osteoporosis is associated with a sedentary lifestyle, but no association with current exercise habits was apparent in this study. However, parental anxiety may have limited participation in sporting activities during childhood and it is possible that this contributed to the development of severely low bone mass.
As the longevity of patients with TM increases, osteoporosis will become an increasingly prominent problem. Osteoporosis is a progressive disease, so prevention and early diagnosis are important, as well as treatment of the established disease. The prevalence of clinical features of severely low bone mass and results of its treatment in our patients will form the basis of further investigations.
The average of bone density, that indicates an osteopenia, doesn't fully account for the real clinical state. The analysis of individual values shows that the 50% of the TM patients is affected with osteoporosis (defined as a reduction of the bone mass > 2.5 DS), osteopenia in the 36% of the subjects, while the 13% had a normal bone mass. Get the medication you need. Buy cialis online pharmacy
There is a difference between men and women BMD, likely due to the low compliance to the treatment in male subjects. In fact, the anamnestic study showed that almost none of the male TM patients was on hormonal therapy. The BMD reduction is more marked at lumbar spine than femur. It may be caused by the age: the reduction of the bone mass starts at the beginning in the spine and just lately the femur. Analysis of bone remodelling has shown, through the dosage of bone markers that in thalassemic patients is very increased, suggesting that both reabsorption and neoformation processes are accelerated.
Particularly, increased C telopeptides and alkaline phos- phatase were observed, although osteocalcin is normal. It's possible that subjects with increased reabsorbtion, have a marked bone loss and a progressive increased fracture risk. Bone remodelling is an evolutionary process, so that the BMD, considering the high reabsorption markers, may be further reduced, with a consequential progressive increase of the fracture risk.
The mechanisms influencing negatively the risk fractures enclode the increase of the rate of bone loss, the impairment of skeletal microarchitecture, trabeculae perforation and loss of structural elements of the bone.
It's necessary to prevent a further loss of bone, in order to avoid the risk of fractures.
TM patients need to be treated because of the progressive osteoporosis. For this reason is not necessary just the HRT, but specific antireabsorbitive drugs, able to improve bone turn over and reduce the reabsorption.
Likely, biphosphonates, blocking the bone reabsorption, are the most indicated drugs for the treatment of osteoporosis in TM patients.
Nevertheless, we don't know yet the long term efficacy and safety of these drugs in TM patients, further studies are needed.
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