不同碘摄入量社区甲状腺功能减退症的五年随访研究

A five-year follow-up study of hypothyroidism in areas with different iodine intakes

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3 761人开展了甲减的横断面调查,5年后其中3 018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＞6 mU/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。

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.