Endocrine Abstracts

The role of TSH in the pathogenesis of thyroid nodule (TN) is controversial.

We have evaluated the prevalence of TN in a group of 800 subjects with and without autoimmune thyroiditis (AT). The prevalence of TN, the number and volume of nodules was evaluated in relation with TSH and antithyroid antibodies titles.

The subjects were of both sex, aged between 20 and 80 years and were recruited in a random manner, in the context of an epidemiological study (FATA); nobody were under farmacologic treatment.

All the subjects were submitted to an echographic study of the neck region and to determination of TSH and antithyroid antibodies (TAb).

We found in the total population a prevalence of TN of 26.8%; TN prevalence was significantly higher (P<0.01) in the subjects with TSH levels less to 4.5 mUI/ml (29.1%) than those with above 4.5 mUI/ml (25.9%); the difference in the prevalence of TN between thyroid antibodies (Ab+) respect to (Ab−) subjects, is not significative.

A negative correlation was found between TSH levels and number of thyroid nodules (r=−0.245 P<0.001); while there was no correlation with the levels of antithyroid antibodies.

Related to volumes of TN the subjects with TSH levels above 4.5 mUI/ml showed a mean TNV of 17.7 cc., significantly reduced (P=0.000) respect to the subjects with TSH below 4.5 mUI/ml (mean TNV of 20.95 cc). A statistically difference (P=0.05) was also observed in the mean TNV between subjects Ab+ (20.01 cc) related to those Ab− (20.96 cc).

Results show TSH seems to play no role in the TN growth, because higher levels are not associated to bigger TN, while TAb presence determines a lesser TN growth.