摘要
目的 本研究旨在探索平均年有效剂量为 6 4mSv的阳江天然放射性高本底辐射的致癌危险 ,为小剂量电离辐射致癌危害概率估计和预测提供对人类的直接观察资料。方法 癌症死亡资料收集采用前瞻性调查方法 ,1979～ 1986年的资料从动态队列中收集 ,1987～ 1998年资料从固定队列获得。两组资料通过记录连接法合并。外照射个人剂量是根据辐射剂量仪测得的环境(室内、外 )辐射水平 ,并考虑不同性别年龄的居留因子来估算。内照射个人剂量根据各类测量数据估算 ,不考虑性别年龄的差异。相对危险 (RR)和超额相对危险系数 (ERR Sv)及 95 %置信区间 (CI)采用Epicure中AMFIT的程序估算。结果 通过对 12 5 0 79人 1979～ 1998年的观察 ,共累积观察了1992 94 0人年 ,期间总共死亡 12 4 4 4例 ,其中癌症死亡 12 0 2例。整个高本底地区全癌死亡的相对危险RR =1 0 0 (95 %CI,0 89～ 1 14 ) ,与对照地区相比无统计学差异。高本底地区高、中、低剂量组全癌死亡相对危险的计算结果 ,均未显示其与对照组有统计学差异 ,也未发现其与剂量呈一致性的变化趋势。调查还表明 ,不同地域、不同观察周期以及诊断水平等因素对全癌相对危险无统计学意义的影响。部位别癌症死亡相对危险分析表明 ,除食管癌高本底地区高于对照地区且具有?
Objective The objective of the study is to explore cancer risk associated with the low-level radiation exposure of average annual effective dose of 6.4 mSv occurring in the high background radiation area(HBRA) in Yangjiang of Guangdong Province, China. Methods The data of cancer mortality for period of 1979-1986 were collected in prospective follow-up survey of dynamic populations and those of 1987-1998 were obtained from a fixed cohort in the same method. Record linkage was used to combine the two data sets. The external dose received by the inhabitants was estimated on the basis of hamlet-specific environmental doses and sex-age-specific occupancy factors, and the fixed values of internal dose regardless of sex and age was assumed.Relative risk (RR) and excess relative risk coefficient (ERR/Sv) and their 95% confidence interval (CI) were calculated using the AMFIT in Epicure. Results During the period of 1979-1998, the follow-up for 125 079 subjects accumulated 1 992 940 person-years and identified 12 444 deaths, including 1202 cancer deaths. The RR of mortality of all cancers in whole HBRA was 1.00 (95% CI, 0.89-1.14) showing no statistical difference between the HBRA and the control area (CA). The RRs of all cancers in low, intermediate and high dose groups in the HBRA did not show statistical difference from the control group, either. The region (Yangdong and Yangxi) and the follow-up period(1979-1986 and 1987-1998) did not evidently modify the results, and the restriction of cancer cases to those with pathology information made no statistically significant change in RRs. In site-specific cancer analysis, only the RR of esophageal cancer showed statistical excess in the HBRA, the others did not show statistical difference between the HBRA and the CA. The comparison of RRs of site-specific cancer mortality among different dose groups and the dose-response analysis of site-specific cancer mortality related to cumulative individual lifetime dose did not give any monotonic trend, the P-values were larger than 0.05 for all, including esophageal cancer. Interestingly to note that, the mortality of liver cancer, which is virus-related and the most common cancer in the studied areas,showed a statistical decrease among the HBRA inhabitants with the dose range of 400 mSv or higher compared to those of 0-199 mSv, RR=0.31 (95%CI, 0.13-0.66). The ERR/Sv for all solid cancers associated with cumulative individual lifetime dose was estimated to be -0.06 (95%CI, -0.60-0.67). Conclusions The mortality of all cancers showed no statistical difference between the HBRA and the CA;any radiation-related excess of site-specific cancer in HBRA could not be found.
出处
《中华放射医学与防护杂志》
CAS
CSCD
北大核心
2004年第2期143-148,共6页
Chinese Journal of Radiological Medicine and Protection
基金
日本体质研究会基金资助
