Current Iodine Nutrition Status and Prevalence of Thyroid Disorders in Tibetan Adults in an Oxygen-Deficient Plateau, Tibet, China: A Population-Based Study

Background: Iodine deficiency (ID) is a global problem in individuals living in an iodine-deficient environment, specifically in mountainous regions. However, data regarding the iodine nutritional status of Tibetan people in the plateau are limited. Methods: A population-based survey was conducted from July 2016 to July 2017 in Lhasa, Tibet, including 12 communities in Lhasa city and 10 surrounding rural areas. The iodine nutritional status of Tibetan people was evaluated using the traditional iodine nutrition indexes: urinary iodine concentration (UIC), thyroid size, serum thyroxine, thyrotropin, thyroglobulin antibody and thyroid peroxidase antibody (TPOAb). Results: A total of 2295 healthy participants were screened, and 2160 participants who had completed all the required examinations were enrolled in this study (response rate, 94.1%). Urinary iodine showed a skewed distribution, with a median (upper and lower quartiles) of 154 (99–229) μg/L. The percentages of low iodine (UIC