Iodine intake level and incidence of thyroid disease in adults in Shaanxi province: a cross-sectional study

BACKGROUND: Exploring the relationship between adult iodine intake level and thyroid disease in Shaanxi area is of great significance for adult scientific iodine supplement and individual iodine supplement strategy. At present, the relationship between iodine and incidence of thyroid disease has not been determined. METHODS: This study was based on the clinical data of 1,159 patients from the Shaanxi Province aged over 18 years and diagnosed with thyroid-related diseases who were admitted to the Xijing Hospital from 2016 to 2020, and 182 provincial healthy volunteers aged over 18 years who agreed and signed informed consent for physical examination in 2020. The chi-square test and nonparametric test were used to investigate the relationship between iodine intake level and thyroid disease. RESULTS: (I) A total of 1,341 patients were enrolled and observed in this study. The median urinary iodine (MUI) was 233.20 μg/L. Compared with the control, group participants the urine iodine (UI) of those with hyperthyroidism, Hashimoto’s thyroiditis (HT), papillary thyroid cancer (PTC), and benign nodules was significantly different (P<0.05). (II) The incidence of PTC was higher in women with excessive iodine intake and people aged ≥45 years (P<0.05). (III) There was no significant difference in urinary iodine (UI), age, gender, and other factors between benign nodules and PTC (P>0.05). CONCLUSIONS: The iodine intake level of adults in Shaanxi is high, which is related to hyperthyroidism, HT, benign nodules, thyroid cancer, and other diseases. There were 3 factors, including excessive iodine intake, age ≥45 years, and female gender, found to be associated with the development of PTC.