Takahashi Ikuno, Abbott Robert D, Ohshita Tomohiko, Takahashi Tetsuya, Ozasa Kotaro, Akahoshi Masazumi, Fujiwara Saeko, Kodama Kazunori, Matsumoto Masayasu
Department of Clinical Studies, Radiation Effects Research Foundation (RERF), Hiroshima, Japan.
BMJ Open. 2012 Feb 3;2(1):e000654. doi: 10.1136/bmjopen-2011-000654. Print 2012.
Use of medical radiotherapy has increased markedly in recent decades. Whether the consequence includes an increased risk of cardiovascular disease remains to be determined. The purpose of this study was to examine the association between radiation exposure and the incidence of stroke among Japanese atomic bomb survivors.
A prospective follow-up study.
Radiation exposure from the atomic bombing was assessed in 9515 subjects (34.8% men) with 24-year follow-up from 1980. Subjects were free of prevalent stroke when follow-up began.
Stroke events and the underlying cause of death were reviewed to confirm the first-ever stroke. Subtypes (ischaemic and haemorrhagic events) were categorised based on established criteria according to the definitions of typical/atypical stroke symptoms.
Overall mean radiation dose (±SD) in units of gray (Gy) was 0.38±0.58 (range: 0-3.5). During the study period, 235 haemorrhagic and 607 ischaemic events were identified. For men, after adjusting for age and concomitant risk factors, the risk of haemorrhagic stroke rose consistently from 11.6 to 29.1 per 10 000 person-years as doses increased from <0.05 to ≥2 Gy (p=0.009). Incidence also rose within the dose range <1 Gy (p=0.004) with no dose threshold. In women, the risk of haemorrhagic stroke rose with increasing radiation exposure but not until doses reached a threshold of 1.3 Gy (95% CI 0.5 to 2.3). Among women, for doses <1.3 Gy, differences in stroke risk were modest (13.5 per 10 000 person-years), while it increased to 20.3 per 10 000 person-years for doses that ranged from 1.3 to <2.2 Gy and to 48.6 per 10 000 person-years for doses that were higher (p=0.002). In both sexes, dose was unrelated to ischaemic stroke.
While the risk of haemorrhagic stroke increases with rising radiation exposure for both sexes, effects in women are less apparent until doses exceed a threshold at 1.3 Gy.
近几十年来，医学放射治疗的使用显著增加。其后果是否包括心血管疾病风险增加仍有待确定。本研究的目的是调查日本原子弹幸存者中辐射暴露与中风发病率之间的关联。
一项前瞻性随访研究。
对9515名受试者（男性占34.8%）的原子弹爆炸辐射暴露情况进行了评估，从1980年开始进行了24年的随访。随访开始时，受试者无中风病史。
回顾中风事件和潜在死因以确认首次中风。根据典型/非典型中风症状的定义，按照既定标准对亚型（缺血性和出血性事件）进行分类。
以格雷（Gy）为单位的总体平均辐射剂量（±标准差）为0.38±0.58（范围：0 - 3.5）。在研究期间，共识别出235例出血性事件和607例缺血性事件。对于男性，在调整年龄和伴随风险因素后，随着剂量从<0.05 Gy增加到≥2 Gy，出血性中风的风险从每10000人年11.6例持续上升至29.1例（p = 0.009）。在<1 Gy的剂量范围内发病率也有所上升（p = 0.004），且无剂量阈值。对于女性，出血性中风的风险随着辐射暴露增加而上升，但直到剂量达到1.3 Gy的阈值时才出现（95%置信区间0.5至2.3）。在女性中，对于剂量<1.3 Gy，中风风险差异不大（每10000人年13.5例），而对于1.3至<2.2 Gy的剂量，风险增加到每10000人年20.3例，对于更高剂量则增加到每10000人年48.6例（p = 0.002）。在两性中，剂量与缺血性中风无关。
虽然两性出血性中风的风险均随着辐射暴露增加而上升，但在女性中，直到剂量超过1.3 Gy的阈值时，影响才较为明显。
