Cortical bone density normalized after antithyroid therapy
MedWire News: Children with hyperthyroidism treated with antithyroid medication have improved bone density at 1 year, research shows.
Additionally, after 2 years, the treated patients had cortical bone density levels considered normal, report Pisit Pitukcheewanont (University of Southern California, Los Angeles, USA) and colleagues in the journal Osteoporosis International.
Osteoporosis is a common skeletal problem in patients with hyperthyroidism. Reductions in cortical, but not cancellous, bone density have been reported in children and adolescents with untreated hyperthyroidism.
However, it is unknown whether or not the attainment of euthyroidism with antithyroid medication improves cortical bone density, explain the researchers.
In the present study, the group assessed bone size and density using computed tomography (CT) in 15 children and adolescents treated with antithyroid medication. At 1 year, all patients had normal thyroid gland function.
At 1 year post-treatment, cortical cross-sectional area (CSA), cortical bone area and bone density, and cancellous CSA and bone density were significantly increased in all patients, relative to baseline. But after adjusting for age, height, weight, and Tanner stage, only the increase in cortical bone density remained statistically significant.
The increase in cortical bone density remained below levels considered normal at 1 year in six of the 15 patients treated. However, at 2 years after treatment, the cortical bone density Z-scores were in the normal range for all 10 patients.
Five patients did not undergo CT scans at 2 years; two of these patients had normal cortical bone density Z-scores at 1 year.
The researchers point out that these results differ from studies that included adult patients, in which normalization of bone density required normal thyroid gland function for at least 3 years.
"Our results of normalization of cortical BD [bone density] after 2 years of treatment suggest that improvement of mineral metabolism after achievement of euthyroidism occurs faster in younger hyperthyroid patients," conclude Pitukcheewanont and colleagues.
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