Konno N, Makita H, Yuri K, Iizuka N, Kawasaki K
Department of Internal Medicine, Hokkaido Central Hospital for Social Health Insurance, Sapporo, Japan.
J Clin Endocrinol Metab. 1994 Feb;78(2):393-7. doi: 10.1210/jcem.78.2.8106628.
The prevalence of thyroid dysfunction in relation to iodine intake was studied in adults (n = 1061) in five coastal areas of Japan that produce iodine-rich seaweed (kelp). The prevalence of hyperthyroidism (TSH < 0.15 mU/L) was similar in these areas, whereas that of hypothyroidism (TSH > 5.0 mU/L) varied from 0-9.7%. The relative frequency of above normal iodide concentration in the morning urine (> or = 75 mumol/L) [high urinary iodide (UI)] varied from 3.7%-30.3%. Together with previously reported results of a noncoastal city, the frequency of high UI correlated significantly with that of hypothyroidism with negative thyroid autoantibody (r = 0.829, n = 6, P < 0.05) but not with positive thyroid autoantibody (r = 0.278, NS) or with that of hyperthyroidism (r = 0.038, NS). Hypothyroidism was more prevalent in thyroid autoantibody-negative subjects with high UI (group II, 12.1%) than with normal UI (group I, 2.3%) (P < 0.001). The TSH [21.9(6.5-73.7)mU/L] (mean +/- SD) and thyroglobulin [288 (182-456) micrograms/L] levels in group II were significantly higher than the respective levels in group I [9.6(3.7-25.3)mU/L and 123 (38-399) micrograms/L] (P < 0.05). Free T4 of group II (9.9 +/- 3.9 pmol/L) was significantly lower than in group I (14.2 +/- 3.9 pmol/L) (P < 0.05). These results indicate that 1) the prevalence of hypothyroidism in iodine sufficient areas may be associated with the amount of iodine ingested; 2) hypothyroidism is more prevalent and marked in subjects consuming further excessive amounts of iodine; and 3) excessive intake of iodine should be considered an etiology of hypothyroidism in addition to chronic thyroiditis in these areas.
在日本五个盛产富碘海藻（海带）的沿海地区，对1061名成年人进行了甲状腺功能障碍与碘摄入量关系的研究。这些地区甲状腺功能亢进（促甲状腺激素<0.15 mU/L）的患病率相似，而甲状腺功能减退（促甲状腺激素>5.0 mU/L）的患病率在0%-9.7%之间。晨尿中碘化物浓度高于正常水平（≥75 μmol/L）[高尿碘（UI）]的相对频率在3.7%-30.3%之间。与之前报道的一个非沿海城市的结果一起，高UI频率与甲状腺自身抗体阴性的甲状腺功能减退频率显著相关（r = 0.829，n = 6，P < 0.05），但与甲状腺自身抗体阳性（r = 0.278，无统计学意义）或甲状腺功能亢进（r = 0.038，无统计学意义）无关。甲状腺自身抗体阴性且尿碘高的受试者（II组，12.1%）甲状腺功能减退的患病率高于尿碘正常的受试者（I组，2.3%）（P < 0.001）。II组的促甲状腺激素[21.9(6.5 - 73.7)mU/L]（均值±标准差）和甲状腺球蛋白[288(182 - 456)μg/L]水平显著高于I组的相应水平[9.6(3.7 - 25.3)mU/L和123(38 - 399)μg/L]（P < 0.05）。II组的游离甲状腺素（9.9±3.9 pmol/L）显著低于I组（14.2±3.9 pmol/L）（P < 0.05）。这些结果表明：1）碘充足地区甲状腺功能减退的患病率可能与碘摄入量有关；2）摄入过量碘的受试者中甲状腺功能减退更为普遍且明显；3）在这些地区，除了慢性甲状腺炎外应将过量碘摄入视为甲状腺功能减退的一个病因。
