TG and autoimmune thyroid disease: In an earlier study on the thyroid hormone, it has been shown that with aging, the measurement of serum deiodinase levels in a range of healthy adults has demonstrated a significant inverse correlation of 3’,3’-diiodothyronine, 3’.5’-diiodothyronine, and 3,5-diiodothyronine levels. Also, it can be seen in elderly individuals due to the increasing incidence and prevalence of autoimmune thyroiditis that occurs with aging [9].