Study on the change of prevalence of autoimmune thyroiditis in Guiyang city after adjustment of salt iodine content / 中华内分泌代谢杂志

ABSTRACT

Objective To investigate the change of prevalence of autoimmune thyroiditis in Guiyang city after adjustment of salt iodine content, and to study the link between the level of iodine intake and the development of autoimmune thyroiditis. Methods With cluster sampling method, a cross-sectional study was conducted among adults aged 20 years old or above in Guiyang in 2009 (before adjustment, n=1 509) and 2015 (after adjustment, n=1 368). After an overnight fasting, thyroid stimulating hormone (TSH), thyroid peroxidase antibody (TPOAb), and thyroglobulin antibody (TgAb) were measured. The serum FT4 and FT3 were determined for the subjects with abnormal TSH. Meanwhile, urine iodine levels of children aged 8-10 years old in the same community were measured after an overnight fasting in these two studies. Results In 2009, the median level of 8-10 years old children′s urinary iodine was 228.7 μg/L. The prevalence of positive TPOAb, positive TgAb, and thyroid autoantibodies (TAAs) were 14.38%, 13.59%, 18.89%, the standardized prevalence were 14.35%, 13.59%, 18.89% respectively. The prevalence of subclinical hypothyroidism, autoimmune thyroiditis were 14.12% and 4.44%, with the standardized prevalence were 14.12%, 4.42% respectively. In 2015, the median urinary iodine level of 8-10 years old children was 190.1 μg/L, the prevalence of positive TPOAb, positive TgAb, and TAAs were 8.77%, 7.82%, 11.77%, the standardized prevalence were 8.98%, 7.97%, 12.13% respectively; the prevalence of subclinical hypothyroidism, autoimmune thyroiditis were 22.89%, 2.92%, with the standardized prevalences of 23.19%, 3.02% respectively. Conclusion After adjustment of salt iodine content, the iodine nutrition in Guiyang is at the appropriate level, and the values of TPOAb, TgAb, TAA, and autoimmune thyroiditis in adults of Guiyang city were all decreased.