Are ethnic differences, urinary iodine status, lead and cadmium exposure associated with thyroid autoimmunity and hypothyroid status? A cross-sectional study

ObjectiveWe aimed to evaluate the effects of different ethnicities and potential environmental exposure on the prevalence of thyroid autoimmune status and hypothyroid status.DesignThe data were obtained from two cross-sectional studies.Participants2105 participants in Shanghai (Han) and 772 participants in Yunnan Honghe Prefecture (Han, Yi, Miao and Hani), aged 18–75 were enrolled.MethodsParticipants underwent several checkups, including urinary iodine concentration, blood lead (BPb) and blood cadmium (BCd), thyroid peroxidase antibody (TPOAb), thyroglobulin antibody (TgAb), thyroid stimulating hormone (TSH) as well as thyroid ultrasonography (US). Thyroid autoimmune status was defined as: antithyroid antibody positive (ATA+): TPOAb + or TgAb+; and ATA + and US+: TPOAb + or TgAb + together with characteristic US features.ResultsThe standardised prevalence of thyroid autoimmune positivity in Yunnan were higher than those in Shanghai (TPOAb+: 13.56% vs 8.27%, pConclusionsHigher levels of UI/Cr, BPb and BCd may be associated with thyroid autoimmunity and hypothyroid status.