Association between urinary iodine concentration and the risk of papillary thyroid cancer by sex and age: a case–control study

Abstract Previous studies on dietary iodine intake and the risk of papillary thyroid cancer (PTC) have demonstrated inconsistent results. We aimed to evaluate the association between urinary iodine concentration (UIC), a surrogate biomarker for dietary iodine intake, and the risk of thyroid cancer stratified by sex and age in an iodine-sufficient area. A hospital-based case–control study was conducted in Seoul, South Korea. A total of 492 cases of newly diagnosed PTC and 595 controls were included. Compared with the lowest quartile of creatine-adjusted UIC (