Endocrine Abstracts

Objective: There are contradictory results regarding the possible association of the TSHR polymorphism D727E with TMNG. Furthermore the influence of smoking on the thyroid volume has been reported by several authors. A possible association of smoking with thyroid nodules and particularly TMNG has not been investigated up to date.

Methods: In this study, 88 patients with TMNG were included. Diagnosis was verified by ultrasonography, scinthiscan, and measurement of TSH, fT4 and fT3. Patients were age- and sex-matched to 88 controls without any thyroid disorders. The polymorphism was detected by denaturating gel electrophoresis (DGGE).

Results: The prevalence of polymorphism D727E in the TMNG population (23.9%) did not deviate significantly (P=0.355) from the control group (18.2%). There was no significant (P=0.601) difference for thyroid volumes between polymorphism carriers (PC) (16.5 ml) and wildtype probands (WP) (18.5 ml). Moreover, also within the TMNG group (n=88) and the control group (n=88) there was no significant (TMNG: P=0.603; controls: P=0.332) difference for thyroid volumes between PC and WP (TMNG: PC 36 ml, WP 36.5 ml; controls: PC 13.9 ml, WP 11.6 ml). Compared to nonsmokers (n=132, 44.7%) the prevalence of TMNG was significantly higher (P<0.05) for smokers (n=44, 65.9%) in the entire population (TMNG and controls). Smokers also had a significantly higher thyroid volume than nonsmokers in the entire population (TMNG and controls, n=176) (smokers: 34 ml, nonsmokers: 15.7 ml, P<0.05). Moreover, also within the TMNG group thyroid volumes of smokers (43 ml) differed significantly from nonsmokers (31 ml, P<0.05) and in the control group smokers tended to have a higher thyroid volume (smokers: 15.8 ml, nonsmokers: 11.6 ml, P=0.119).

Conclusion: Neither an association of the polymorphism with TMNG nor its association with the thyroid volume was evident in this study. However, smoking clearly showed a positive association with the thyroid volume. Furthermore, our results suggest an association of smoking with TMNG.