The relationship between workers with occupational exposure to low-dose ionizing radiation and changes in the hematological profiles

摘要

Objectives: To evaluate possible changes in the hematological profiles and serum-thyroid hormones of workers with long-term exposure to low-dose ionizing radiation and determine whether there is a dose-response effect according to exposure duration Methods: In study 1 we collected health examination reports from employees who worked near radiation source for more than 10 years in Chiayi Christian Hospital during 2005 to 2014 as case group In addition we also selected workers but who were not working on radiation-related jobs in the same hospital as control group We excluded those with a history of cancer autoimmune disease anemia liver cirrhosis or renal disease White blood cell count red blood cell count platelet count and hemoglobin were selected from reports of health examination in both group and we used repeated measure ANOVA to compare the difference of hematological changes between case and control group In study 2 we collected reports of health examination from employees who worked on radiation-related jobs at Chia-Yi Cristian Hospital for more than 2 years during 2002 to 2013 Similarly we collected health examination reports from workers in Lan-Yu nuclear waste deposal for more than 2 years during 2007 to 2011 in study 3 We excluded those with a history of cancer autoimmune disease and systemic diseases such as liver cirrhosis or end-stage renal disease in study 2 and study 3 Then we analyzed thyroid hormones in the health-examination reports to determine whether the changes in serum-thyroid hormones were related to exposure duration and the generalized estimating equation for repeated measures with thyroid hormones was used to examine the association between working years and ionizing radiation exposure both in study 2 and study 3 Results: In study 1 there were no significant differences in the changes of white blood cell count(WBC) red blood cell count(RBC) platelet and hemoglobin(Hb) between case group (n=69) and control group (n=74) In study 2 326 hospital workers with low-dose radiation exposure were included and significant declines of Triiodothyronine(T3) (odds ratio 0 96; 95% confidence interval 0 96–0 97) and Thyroxine(T4) (odds ratio 0 89; 95% confidence interval 0 87–0 91) after occupational exposure to low-dose ionizing radiation were found Additionally a significant linear dose-response relationship was observed between exposure duration and the decline in the serum concentrations of T3 and T4 However there is no significant dose-response relationship between exposure duration and the decline in the serum concentrations of TSH except technician group (odds ratio 0 96; 95% confidence interval 0 92–1 0) Moreover there is significant decline in serum concentration of T4 in workers in Lan-Yu nuclear waste deposal but there are no significant findings in changes of T3 and TSH in the study 3 Conclusion: Long-term working n radiation-related job might induce decline of thyroid hormones Despite the healthcare workers having an extremely low radiation-exposure dose there was still a dose-response relationship between occupational exposure to ionizing radiation and the decline in the serum concentrations of T3 and T4 This indicates that the serum concentration of thyroid hormones was more sensitive than hematological profiles and it could be used as early-detection biomarkers for radiation exposure before thyroid disease arises Accordingly these results suggest we should reconsider the health impacts of occupational exposure to radiation and provide more protection in the workplace

獎項日期	2016 8月 31
原文	English
監督員	How-Ran Guo (Supervisor)