Iodine Nutrition and the Prevalence Status of Thyroid Nodules in the Population: a Cross-sectional Survey in Heilongjiang Province, China

The aim of this study was to determine the iodine nutritional status and the epidemiological characteristics of thyroid nodules (TNs) in the adult population of Heilongjiang Province. From December 2017 to December 2018, a total of 3661 adults aged 20–70 years were selected through probability proportional to size (PPS) sampling for a cross-sectional survey. During the field epidemiological investigation, each participant received a questionnaire survey and thyroid ultrasonography examination. The iodine concentrations in casual urine specimens and household edible salt were measured. The household coverage of iodized salt was 86.56%. The median urinary iodine concentration (MUIC) in the adult population in Heilongjiang Province was 161.57 μg/L (25th–75th percentile: 100.35–245.15 μg/L). The prevalence of TNs was 36.88%, and the prevalence in females was significantly higher than that in males (41.25% vs 32.50%, χ 2 = 11.841, P