Iodine nutrition and prevalence of sonographic thyroid findings in adults in the Heilongjiang Province, China

BACKGROUND: Thyroid disease and thyroid nodules are common clinical problems. Iodine nutrition plays an important role in thyroid disease evolution. Here, we aimed to estimate the iodine nutritional status and prevalence of thyroid disease in the adults of the Heilongjiang Province in northeast China. METHODS: We performed a cross-sectional ultrasound (US)-based survey on volunteers aged 20–70 years from 30 regions of the Heilongjiang Province. The participants were recruited using the probability proportional to size (PPS) method, and consent for US screening was obtained from them. The survey was performed by trained technicians using the same US equipment with a 6–15 MHz linear transducer (MyLab 30 cv, Italy) and was hosted in public community locations such as local hospitals and outpatient departments. Information on basic demographic characteristics, such as urinary iodine and iodine intake were collected. The age- and sex-adjusted prevalence of thyroid disease was determined through direct standardization and reported using the province’s population in 2016 as reference. RESULTS: From December 12, 2017, to March 10, 2019, 3,754 participants with a mean age of 48.65 (±12.39) years participated in the study. Of them, 3,643 had reliable urinary iodine data. The median urinary iodine and salt iodine concentrations within the normal range were 163.30 µg/L and 24.30 mg/kg, respectively. The age- and sex-adjusted prevalence of thyroid disease was 52.91%. Diffuse thyroid disease (DTD), focal thyroid lesions (FTL), and coexistence of both diseases were prevalent in 8.68%, 36.58%, and 7.65% of the participants, respectively. The prevalence of the five categories according to US-based survey features in the ACR TI-RADS (i.e., TR1, TR2, TR3, TR4, and TR5) was 7.71%, 14.53%, 3.44%, 14.82%, and 3.51%, and the prevalence of nodules that needed fine-needle aspiration was 2.55%. CONCLUSIONS: In Heilongjiang Province, adults aged 20–70 years belong to the optimal iodine status. Further, the salt iodine levels are in the normal range. Thyroid diseases are highly prevalent in this age group; however, the intervention rate is low. We provided population-based estimates of the prevalence of thyroid disease and the iodine status in adults of Heilongjiang Province. These findings are useful to support effective intervention planning for thyroid disease.