TSH - Clinical Aspects of its Use in Determining Thyroid Disease in the Elderly. How Does it Impact the Practice of Medicine in Aging?

The last four decades have seen enormous growth in the efficacy of serum thyroid stimulating hormone (thyrotropin, TSH) assay methodology, establishing TSH as the hallmark of thyroid testing. At the center of the considerations is the strong inverse correlation between serum thyrotropin and free thyroxine concentrations. While it is widely accepted that elevated serum TSH concentrations are consistent with thyroid dysfunction, a vast multitude of additional factors must be considered before an accurate clinical diagnosis can be made followed by an appropriate treatment. Epidemiological studies have demonstrated slightly elevated serum TSH concentrations among the elderly population. There is, however, a debate whether these elevated TSH levels reflect an increased prevalence of hypothyroidism among the elderly or a normal aspect of healthy aging. A comprehensive analysis of the many variables associated with this debate and TSH measurement as a diagnostic tool in aging should provide insight into the clinical efforts to diagnose and treat thyroid disease, particularly in the elderly population.