Population survey of thyroid autoimmunity in Italy. Three year follow up.

Thyroid autoimmunity and primary hypothyroidism have been evaluated in a 3 year interval in 4 samples of general population from Bologna, Napoli, Palermo, Rome and Cagliari. The average prevalence of Mic-Abs was in males 4.1% and in females 10%. A significantly higher prevalence of Mic-Abs was found in the Cagliari sample where it reaches in males 6.1% and in females 20.4% (p less than 0.0005). Likewise Tg-Abs have been found increased in Cagliari (males: 4.6% vs 10.7%; females: 10.0% vs 16.6%; p less than 0.01). In the 3 year follow up Mic-Abs titre increases significantly whereas the Tg-Abs titre remains substantially unchanged. In the initial screening 1.65% of subjects were found to be latent (1.2%) or overt (0.45%) hypothyroids. Hypothyroidism was particularly frequent in the Cagliari sample and was constantly associated with Mic-Abs. In the 3 year follow up only 1 of 8 latent hypothyroids became overt.