Epidemiologic Follow-up Study Of Hypothyroidism In Areas With Different Iodine Intakes

ObjectiveTo investigate epidemiological characteristics of hypothyroidism and factors influencing its outcome in the areas with different iodine intakes.MethodsA cross - sectional epidemiologic study in Panshan ( mild iodine - deficient area) , Zhangwu(mild iodine -deficient area before 1996 and more than iodine - sufficient area after that) and Huanghua (iodine - excessive area) was performed in 1999. Questions about thyroid disorders were asked to 3761 subjects. The thyroid function , thyroid autoantibodies (TAA) , urinary iodine concentration and thyroid B ultrasound were performed in the subjects. One hundred and sixty subjects with hypothyroidism ( 39 with overt hypothyroidism and 121 with subhy-pothyroidism) were found in 1999. An epidemiologic follow - up study was conducted in subjects investigated in the above areas in 2004.Results80. 24% of subjects participated in the follow - up study. The incidence of totle hypothyroidism was 0. 45,0. 94 and 0. 87/1000person/year and the incidence of spontaneous hypothyroidism was 0,0.94 and 0.29/1000person/year in Panshan, Zhangwu and Huanghua, respectively. Spontaneous hypothyroidism oc-cured more frequently in Zhangwu than in Panshan. Positive thyroid autoantibodies alone, raised serum TSH ( > 4. 8mU/L) alone, both poisitive thyroid au-...