中文摘要：

目的 研究不同碘营养状态社区甲状腺功能减退症（甲减）的流行病学特点，探讨影响其发生及转归的因素。方法 1999年对盘山（轻度碘缺乏）、彰武（轻度碘缺乏基础上补碘至超足量）和黄骅（长期碘过量）社区的3761人开展了甲减的横断面调查，5年后其中3018人接受了随访研究（随访率80．2％）。结果 盘山、彰武和黄骅3个社区临床甲减的5年累积发病率分别为0．23％，0．47％和0．35％。自身免疫性甲状腺炎所致临床甲减的自然转归：55％恢复正常，20％转归为亚临床甲减，25％维持临床甲减；其转归在3个社区间差异无统计学意义。亚临床甲减5年累积发病率分别为0．23％、2．60％和2．89％，彰武和黄骅显著高于盘山（均P〈0．01）。随访亚临床甲减100例，其中5％进展为临床甲减，66％恢复正常。初访时TSH〉6mU／L（OR=3．4）、随访时甲状腺自身抗体阳性（OR=5．3）及对轻度碘缺乏人口过量补碘至超足量（OR=8．0）可能是影响亚临床甲减恢复的不利因素。结论 对轻度碘缺乏社区过量补碘可能导致l临床和亚临床甲减的发生，并影响亚临床甲减的转归，但对临床甲减的转归无显著影响。

英文摘要：

Objective To investigate epidemiological characteristics of hypothyroidism and factors influencing its outcome in the areas with different iodine intakes. Methods An epidemiologic follow-up study of thyroid diseases was performed in Panshan （ iodine deficient ）, Zhangwu [ mild iodine deficiency before universal salt iodination （USI） and more than adequate iodine intakes after USI ] and Huanghua （ iodine excessive） in China. A total of 3 761 subjects were investigated in 1999, and 3 018 （ 80. 2% ） of them were followed up in 2004. FT4, FT3, TSH, thyroid autoantibodies and urinary iodine concentration were determined and thyroid B ultrasound was performed in all participants. Results Five-year cumulative incidence of overt hypothyroidism was 0.23% ,0.47% and O. 35% in Panshan, Zhangwu and Huanghua, respectively. Twenty patients with autoimmuneinduced overt hypothyroidism did not comply with the physician＇s orders to take thyroxine. Thyroid function spontaneously turned to normal in 55% of them, turned to subclinical hypothyroidism in 20% and maintained overt hypothyroidism in 25%. Five-year cumulative incidence of subclinical hypothyroidism in Zhangwu （2.60%） and Huanghua （2.89%） were significantly higher than that in Panshan（0.23% ） （ both P 〈 0.01 ）. One hundred patients with subclinical hypothyroidism were followed up, and 5% of them developed overt hypothyroidism, 66% turned to euthyroidism and 29% maintained subclinical hypothyroidism. Raised serum TSH（ 〉 6 mU/L） in the original survey （ OR = 3.4 ）, positive thyroid autoantibodies in the follow-up study （ OR = 5.3 ） and more than adequate iodine supplementation in the mild iodine-deficient population （OR = 8. O） were risk factors influencing outcome of subclinical hypothyroidism. Conclusion More than adequate iodine supplementation among a population in the mildly iodine-deficient area may increase the incidence of overt and subclinical hypothyroidism,and also influence outcome of subclinical hypothyroidism