[Increased risk of bone-fragility-related fractures in TSH--suppressive thyroxine treatment]

Low concentration of serum thyrotropin (TSH) is a common finding in patients attending primary care as well as in apparently healthy elderly individuals. Low TSH concentration in apparently healthy elderly seems to be a significant risk factor for the development of dementia and for premature mortality. In thyroxine-treated women, TSH < 0.10 mlU/L appears to be a significant risk factor for fractures of the hip and vertebrae. Considering also the decrease in anti-thyroid immunoactivity observed in thyroxine treatment of autoimmune thyroiditis, as measured with antithyroperoxidase antibodies, we conclude that TSH concentrations during thyroxine substitution treatment should be held within the lower end of the health-associated reference interval.