Department of Preventive Medicine, Korea University College of Medicine, 73, Goryeodae-ro, Seongbuk-gu, Seoul, 02841, South Korea.
Hirosoft International, Eureka, CA, USA.
Environ Health. 2019 Mar 11;18(1):19. doi: 10.1186/s12940-019-0460-z.
Thyroid cancer rates, especially among children, are known to be increased by radiation exposure. However, little is known about the impact of chronic low-dose radiation exposure on thyroid cancer risk in adulthood. This study examined radiation effects on thyroid cancer rates as well as an overall evaluation of thyroid cancer risk among medical radiation workers.
Data on all diagnostic medical radiation workers enrolled in the national dosimetry registry between 1996 and 2011 were linked with the cancer registry data through 2015. Standardized incidence ratios (SIRs) were used to compare the observed cancer incidence rates in this population to those for the general population while internal comparisons were used to estimate relative risks (RRs) for occupational history and excess relative risks (ERRs) were used to quantify the radiation dose-response relationship.
Overall, 827 thyroid cancer cases were reported among 93,922 medical radiation workers. Thyroid cancer SIRs were significantly higher than expected for both men (SIR 1.72, 95% confidence interval [CI] 1.53 to 1.91) and women (SIR 1.18, 95% CI 1.08 to 1.28). However, RRs for thyroid cancer by job title and duration of employment showed no particular pattern among diagnostic medical radiation workers. There were no indications of a significant dose effect on thyroid cancer rates for either men (ERR/100 mGy 0.07, 95% CI -0.38 to 0.53) or women (ERR/100 mGy -0.13, 95% CI -0.49 to 0.23). The findings were similar for different job titles or when limited to workers employed for at least one year.
While thyroid cancer incidence rates among Korean medical radiation workers were somewhat higher than those in the general population, there was no significant evidence that this increase was associated with occupational radiation dose. Additional follow-up together with consideration of other risk factors should provide useful information on thyroid cancer rates in this cohort.
已知辐射暴露会导致甲状腺癌发病率增加，尤其是儿童。然而，人们对成年人中慢性低剂量辐射暴露对甲状腺癌风险的影响知之甚少。本研究检查了辐射对甲状腺癌发病率的影响，以及对医疗放射工作人员甲状腺癌风险的全面评估。
将 1996 年至 2011 年间全国剂量计登记处登记的所有诊断性医疗放射工作人员的数据与癌症登记数据相联系，直至 2015 年。标准化发病比（SIR）用于比较该人群的观察癌症发病率与一般人群的发病率，内部比较用于估计职业史的相对风险（RR），超额相对风险（ERR）用于量化辐射剂量-反应关系。
总体而言，在 93922 名医疗放射工作人员中报告了 827 例甲状腺癌病例。男性（SIR 1.72，95%置信区间 [CI] 1.53 至 1.91）和女性（SIR 1.18，95%CI 1.08 至 1.28）的甲状腺癌 SIR 均显著高于预期。然而，按职务和就业年限划分的诊断性医疗放射工作人员的甲状腺癌 RR 没有特定模式。男性（每 100mGy 的 ERR/100mGy 为 0.07，95%CI -0.38 至 0.53）或女性（ERR/100mGy -0.13，95%CI -0.49 至 0.23）的甲状腺癌发生率均无明显剂量效应迹象。不同职务或至少就业一年的工人中，结果相似。
虽然韩国医疗放射工作人员的甲状腺癌发病率略高于一般人群，但没有证据表明这种增加与职业辐射剂量有关。进一步的随访以及对其他危险因素的考虑应提供有关该队列中甲状腺癌发病率的有用信息。
