Konno N, Yuri K, Taguchi H, Miura K, Taguchi S, Hagiwara K, Murakami S
Department of Medicine, Hokkaido Central Hospital for Social Health Insurance, Sapporo, Japan.
Clin Endocrinol (Oxf). 1993 Mar;38(3):273-81. doi: 10.1111/j.1365-2265.1993.tb01006.x.
The present study was designed to investigate the prevalence of thyroid dysfunction and its relation to thyroid autoantibodies and urine iodide concentration in apparently healthy people residing in Sapporo, a city of northern Japan, where the iodine intake is high.
Serum TSH and thyroid autoantibodies, and urine iodide were measured in 4110 people (2931 men and 1179 women) (age 45.6 +/- 10.3 years (mean +/- SD)) who were recruited at the hospital for medical examinations.
The thyroid autoantibodies were positive in 6.4% of males and 13.8% of females with an age-related increase. Of the people with positive antibodies, 87.2% had normal TSH values (0.15-5.0 mU/l) as measured by a sensitive assay. The prevalence of unsuspected hyperthyroidism as defined by suppressed TSH values was 0.61%, of which 64% was diagnosed as Graves' disease based on positive thyrotrophin receptor antibody results. The prevalence of unsuspected hypothyroidism, as evidenced by supranormal TSH, was 0.68% for males and 3.13% for females with an age-related increase. Of those with hypothyroidism, 45.5% were autoantibody positive. The overall prevalence of Hashimoto's thyroiditis was 13.11% for females and 6.15% for males. The urine iodide levels of hypothyroidism with a positive autoantibody of 38.5 (17.7-83.9) mumol/l and a negative autoantibody of 34.9 (17.9-67.9) mumol/l were both significantly higher than that of normal subjects (26.9 (14.6-49.6) mumol/l) (P < 0.01). When iodine intake was restricted for 6-8 weeks for hypothyroid subjects, the elevated TSH and thyroglobulin and low free T4 levels were reversed in the autoantibody negative but not in the positive group.
This study provides further information on the prevalence of thyroid dysfunction and autoimmune thyroid diseases in an iodine sufficient area. In addition, it suggests that more than half of the patients with unsuspected hypothyroidism were negative for autoantibodies and that the excessive iodine intake may be involved in causing latent hypothyroidism.
本研究旨在调查居住在日本北部城市札幌的表面健康人群中甲状腺功能障碍的患病率及其与甲状腺自身抗体和尿碘浓度的关系，该地区碘摄入量较高。
对在医院接受体检招募的4110人（2931名男性和1179名女性）（年龄45.6±10.3岁（均值±标准差））进行血清促甲状腺激素（TSH）、甲状腺自身抗体和尿碘检测。
甲状腺自身抗体在6.4%的男性和13.8%的女性中呈阳性，且随年龄增长而增加。在抗体阳性人群中，通过灵敏检测法测得87.2%的人TSH值正常（0.15 - 5.0 mU/l）。根据TSH值降低定义的未被怀疑的甲状腺功能亢进患病率为0.61%，其中64%基于促甲状腺激素受体抗体结果被诊断为格雷夫斯病。根据TSH值升高证明的未被怀疑的甲状腺功能减退患病率，男性为0.68%，女性为3.13%，且随年龄增长而增加。在甲状腺功能减退患者中，45.5%自身抗体呈阳性。女性桥本甲状腺炎的总体患病率为13.11%，男性为6.15%。自身抗体阳性的甲状腺功能减退患者尿碘水平为38.5（17.7 - 83.9）μmol/l，自身抗体阴性的为34.9（17.9 - 67.9）μmol/l，两者均显著高于正常受试者（26.9（14.6 - 49.6）μmol/l）（P < 0.01）。对于甲状腺功能减退患者，当碘摄入量限制6 - 8周时，自身抗体阴性组升高的TSH和甲状腺球蛋白以及降低的游离T4水平得到逆转，而阳性组未逆转。
本研究提供了碘充足地区甲状腺功能障碍和自身免疫性甲状腺疾病患病率的更多信息。此外，研究表明超过一半未被怀疑的甲状腺功能减退患者自身抗体为阴性，且过量碘摄入可能与导致潜在甲状腺功能减退有关。
