Clinical, biochemical and ultrasonographic characteristics of Hashimoto's thyroiditis patients observed at two endocrine divisions (University Hospital of Catania or Messina) during the indicated years.

In 2005, the population was 1,071,883 in the province of Catania and 657,785 in the province of Messina (http://demo.istat.it/pop2009/index.html). During the period 1995–2005, the total number of thyroid patients referred to the two endocrine divisions approximated 28,000 (Catania) and 11,000 (Messina). In the period 1995–2009 the total numbers of thyroid patients referred to the endocrine division in Catania approximated 49,000. Though our study was not (and was not intended to be) a province-wide screening for HT, in order to give an approximation of the province population-adjusted number of the thyroid patients and HT patients in Catania vs. Messina assuming that all such patients living in the two provinces were referred to the two institutions, the total number of thyroid patients was 2,612 vs. 1,672 per 100,000 (a 1.6-fold difference) while the number of HT patients was 69 vs. 518 per 100,000 (a 7.5-fold difference).
Data are reported as weighted averages, mean ± SD [and median]. P values<0.05 are typed boldface. P values between 0.05 and 0.10 are typed boldface italics.
aComparison between means was made by the Student t-test.
bComparison between rates (weighted averages) was examined by the chi square (χ2) test.
cComparison between serum levels of TgAb or TPOAb missing because of differences in assays (see text, Patients and Methods).