Subclinical thyroid disease occurs when the only lab abnormality is the thyroid-stimulating hormone (TSH) level as the thyroid hormone levels of T3 and T3 are normal. In subclinical hypothyroidism (underactive thyroid), a mild form of hypothyroidism, the TSH is slightly increased. In subclinical hyperthyroidism, a mild form of hyperthyroidism (overactive thyroid), the TSH is slightly low. While moderate to severe thyroid disease clearly have adverse health effects, it is less clear to determine the adverse effects of subclinical thyroid disease. The elderly have an increased risk of moderate to severe thyroid disease and are more susceptible to possible adverse effects, including death. It is unclear whether subclinical/mild thyroid disease is associated with death in the elderly. This study was done to examine to what degree, if any, subclinical hypothyroidism and subclinical hyperthyroidism are associated with early death in the elderly.
THE FULL ARTICLE TITLE:
Grossman A et al. Subclinical thyroid disease and mortality in the elderly: a retrospective cohort study. Am J Med 2016;129:423-30. Epub December 20, 2016.
SUMMARY OF THE STUDY
The study included a total of 17,440 patients 65 years or older from the Clalit Health Medical Organization database in Israel, who had at least one TSH measurement in 2002 and were followed until 2012. Of these, 14,946 patients were normal cases (euthyroid) and 2495 patients had subclinical hypothyroidism or subclinical hyperthyroidism. Patients were divided into 3 groups according to their TSH values: normal (normal TSH value), subclinical hypothyroidism (serum TSH values greater than 4.2 mIU/L) and subclinical hyperthyroidism (serum TSH values less than 0.35 mIU/L). The death rate was compared among the 3 groups.