Hyperthyroidism may be associated with insulin resistance

A recent study presented at the International Thyroid Congress suggests that endogenous subclinical types of hyperthyroidism may have a larger metabolic effect on insulin resistance than the exogenous type of the condition.

"The aim of our study was to compare insulin sensitivity among patients with subclinical hyperthyroidism of different origin and euthyroid controls," wrote lead study author, Jorge N. Rezzonico of the Centro Privado de Endocrinologia in Argentina, Doctor's Guide reports.

The study followed 125 premenopausal normal-weight women who were divided into those with exogenous subclinical hyperthyroidism (SH) resulting from L-T4 treatment for benign goiter, endogenous SH, and exogenous SH resulting from the same treatment for differentiated thyroid cancer, and those with euthyroid as a control.

Patients with all types of subclinical hyperthyroidism had significantly higher levels of insulin and insulin resistance, and lower values of quantitative insulin compared to control patients.

"Insulin resistance is associated with SH, either of endogenous or exogenous origin. However, the endogenous subclinical form might have an even larger metabolic impact," wrote Rezzonico.

According to the Centers for Disease Control, treatment of hyperthyroidism may include antithyroid drugs, radioactive iodine-131 or in rare cases, thyroid surgery.