Linet M S, Freedman D M, Mohan A K, Doody M M, Ron E, Mabuchi K, Alexander B H, Sigurdson A, Hauptmann M
Division of Cancer Epidemiology and Genetics, National Cancer Institute, Department of Health and Human Services, Bethesda, MD 20892, USA.
Occup Environ Med. 2005 Dec;62(12):861-7. doi: 10.1136/oem.2005.020826.
There are limited data on risks of haematopoietic malignancies associated with protracted low-to-moderate dose radiation.
To contribute the first incidence risk estimates for haematopoietic malignancies in relation to work history, procedures, practices, and protective measures in a large population of mostly female medical radiation workers.
The investigators followed up 71,894 (77.9% female) US radiologic technologists, first certified during 1926-80, from completion of a baseline questionnaire (1983-89) to return of a second questionnaire (1994-98), diagnosis of a first cancer, death, or 31 August 1998 (731,306 person-years), whichever occurred first. Cox proportional hazards regression was used to compute risks.
Relative risks (RR) for leukaemias other than chronic lymphocytic leukaemia (non-CLL, 41 cases) were increased among technologists working five or more years before 1950 (RR = 6.6, 95% CI 1.0 to 41.9, based on seven cases) or holding patients 50 or more times for x ray examination (RR = 2.6, 95% CI 1.3 to 5.4). Risks of non-CLL leukaemias were not significantly related to the number of years subjects worked in more recent periods, the year or age first worked, the total years worked, specific procedures or equipment used, or personal radiotherapy. Working as a radiologic technologist was not significantly linked with risk of multiple myeloma (28 cases), non-Hodgkin's lymphoma (118 cases), Hodgkin's lymphoma (31 cases), or chronic lymphocytic leukaemia (23 cases).
Similar to results for single acute dose and fractionated high dose radiation exposures, there was increased risk for non-CLL leukaemias decades after initial protracted radiation exposure that likely cumulated to low-to-moderate doses.
关于长期低至中等剂量辐射与造血系统恶性肿瘤风险的相关数据有限。
在以女性为主的大量医学放射工作人员群体中，提供与工作经历、程序、操作及防护措施相关的造血系统恶性肿瘤的首次发病风险估计。
研究人员对71894名美国放射技师进行随访（女性占77.9%），这些技师于1926年至1980年首次获得认证，从完成基线调查问卷（1983年至1989年）到返回第二份调查问卷（1994年至1998年）、首次癌症诊断、死亡或1998年8月31日（731306人年），以先发生者为准。采用Cox比例风险回归计算风险。
1950年前工作五年或更长时间的技师（基于7例病例，相对风险[RR]=6.6，95%置信区间1.0至41.9）或为患者进行50次或更多次X光检查的技师（RR=2.6，95%置信区间1.3至5.4），除慢性淋巴细胞白血病外的白血病（非CLL，41例）相对风险增加。非CLL白血病风险与受试者近期工作年限、首次工作年份或年龄、总工作年限、使用的特定程序或设备，或个人放疗无关。担任放射技师与多发性骨髓瘤（28例）、非霍奇金淋巴瘤（118例）、霍奇金淋巴瘤（31例）或慢性淋巴细胞白血病（23例）风险无显著关联。
与单次急性剂量和分次高剂量辐射暴露的结果相似，在初次长期辐射暴露数十年后，非CLL白血病风险增加，可能累积至低至中等剂量。
