The study of late low dose effect to thyroid disease in Marshall Islands

1994年和1996年在马绍尔群岛夸贾林和马朱罗的检查结果如下：1.可触及的甲状腺结节的患病率与来自比基尼的角度呈负相关。2.甲状腺功能减退症的患病率和自身抗体阳性与甲状腺的比率明显低于日本成人和长崎原子弹受害者。3.根据世界卫生组织的缺碘标准，三分之一的马朱罗居民被估计为中度缺碘。4.未能完成马歇尔人在原子弹试验时代(1949-58年)的辐射剂量测量。5.在70例细针活检标本中未检测到K-ras癌基因61位密码子突变。6.1994年在Majuo进行的11例甲状腺手术中，病理诊断为7例乳头状癌和3例癌。4例P53蛋白免疫组织化学呈阳性。由于目前还没有剂量学数据，我们无法对该对象得出明确的结论。但根据上述研究结果，本文提出了一些建议。1.从甲状腺结节患病率的地理分布来看，存在原子弹试验低剂量辐射效应的可能性。2.碘摄入量较低可能影响甲状腺结节患病率。3.滤泡性癌的高比例与其他关于辐射诱发甲状腺癌的报道相矛盾。4.在切尔诺贝利经常检测到密码子61 K-ras的突变，但在马绍尔群岛没有发现突变。马绍尔群岛甲状腺肿瘤的原因可能与切尔诺贝利地区不同。

The results from the examination in 1994 and 1996 at Kwajalein and Majuro in Marshall Islands were as follows ;1. The prevalence of palpable thyroid nodules had reverse correlation to the angle rhetafrom Bikini. 2. The prevalence of hypothyroidism and the ratio of positive auto-antibody to thyroid were quite lower than Japanese adults and Nagasaki atomic bomb victims. 3. On the basis of WHO criteria on iodine deficiency, one third of Majuro residents were estimated as moderate iodine deficiency. 4. The radiation dosimetry for the Marshall people during atomic bomb testing era (1949-58) could not be completed. 5. The mutation of codon 61, K-ras oncogene was not detected in 70 fine needle aspiration biopsy specimens. 6. In eleven operated thyroid in 1994 at Majuro, seven papillary carcinomas and three carcinomas were pathologicaly diagnosed. The p53 protein was immunohistochemically positive in four cases.Since no dosimetry data was available for this time, we could not have definite conclusions on the object. But some suggestions were given from the above results. 1. From the geographical distribution of the prevalence of thyroid nodule, there was possibility of low dose radiation effect of atomic bomb testing. 2. Rather poor iodine intake might affect the thyroid nodule prevalence. 3. The high ratio of follicular carcinoma was contradictory to other reports on the thyroid cancer induced by radiation. 4. In Chernobyl the mutation of codon 61, K-ras was frequently detected, but none in Marshall Islands. The cause of the thyroid tumors in Marshall Islands might be different from that in the Chernobyl area.