The changing incidence of thyroid carcinoma in Shenyang, China before and after universal salt iodization

Background An increase in the prevalence of thyroid disease has been found with increasing iodine intake, since universal salt iodization (USI) was instituted throughout China in 1996. The aim of this study was to analyze the incidence of thyroid carcinoma (TC) before and after USI in Shenyang, a city of northeastern China.