Thyroid hormone excess and bone--a clinical review

During the past several years, studies have suggested that exogenous thyroid hormone may adversely affect bone. In order to address this contention and to put the issue in perspective for clinicians who treat patients with thyroid hormone replacement, the available literature was reviewed, and the various study populations were characterized. Age, gender, and menopausal status of the patient are important factors, as are the indication for thyroid hormone replacement and the extent, duration, and severity of prior hyperthyroidism. Reliable measures of bone mineral density, particularly dual-energy x-ray, absorptiometry have become available, providing a more accurate reflection of this parameter in patients receiving thyroxine therapy in comparison with control subjects. The bulk of evidence indicates that long-term thyroxine therapy is safe if the dose is carefully monitored. Treatment with thyroxine does not produce clinically significant bone disease.