阳江天然放射性高本底地区居民1987～1995年非肿瘤死亡再分析

目的　进一步分析阳江天然放射性高本底地区居民非肿瘤性疾病危险及其影响因素。方法　采用定群队列研究方法对居住在高本底地区和对照地区居民进行调查 ,现场调查分为队列成员追踪随访和死因确认。按外照射年剂量水平 ,将居住在高本底地区的人群分为高、中、低剂量 3个组 ,进行内比较。高本底地区 3个剂量组与对照组之间的比较采用相对危险 (RR) ,并计算了个人终生累计剂量与超额相对危险 (ERR/Sv)。结果　高本底地区居民非肿瘤死亡比对照地区增加 9% ,死亡危险明显高于对照地区 ,RR =1 0 9,P =0 0 1;危险显著增加的非肿瘤疾病主要是消化系统疾病 ,RR =1 4 6 ,P =0 0 0 4 ,其中慢性肝炎与肝硬化为RR =1.98,P =0 0 0 4 ;危险显著降低的主要是传染和寄生虫疾病 (RR =0 81,P =0 0 4 ) ,其中肺结核死亡为RR =0 .5 8,P <0 0 0 1。对各种死因及肝硬化危险在不同剂量组间的齐性检验结果表明 ,消化系疾病 (P =0 0 1)及肝硬化 (P =0 0 4 )组间差异有显著性 ,其ERR(95 %CI) /Sv也分别为 2 18(0 2 2 ,7 6 4 )和 10 94 (1 34,NA)。结论　高本底地区居民消化系疾病中的慢性肝炎和肝硬化死亡率高于对照地区且有统计学意义 ,不同于癌症死亡的结果 ;肺结核死亡则显著低于对照地区。但由于目前资料的局限性 ,

Reanalysis of noncancer deaths(1987-1995) among residents in high background radiation area of Yangjiang, China

Objective To further analyze non-cancer mortality rates and relevant influencing factors among the residents in high background radiation area(HBRA)and its control area(CA). Methods The data for the period 1987-1995 were obtained from a fixed cohort by prospective survey.The mortality investigation on the spot consisted of two steps,i.e.the follow-up of the cohort members and the ascertainment of causes of death.On the basis of the hamlet-specific average of annual external dose,the cohort members were classified into four groups for internal comparison:high,medial and low dose groups in HBRA and control group in CA.Relative risk(RR),excess relative risk(ERR/Sv)and its 95% confidence interval(CI) were estimated using AMFIT program in Epicure. Results During the period 1987-1995,the noncancer mortality in HBRA increased by 9% compared with that in the control group,and the relative risk of noncancer diseases was 1.09( P =0.01),indicating a statistically significant excess mortality in the HBRA.The significantly increased noncancer death was caused by diseases of digestive system, with a RR of 1.46( P =0.006);the relative risk of chronic liver diseases including cirrhosis was 1.98( P =0.004).The significantly decreased noncancer death rates were observed for the infectious and parasitic diseases,the RR being 0.81( P =0.04);for pulmonary tuberculosis,RR 0.58( P <0.001).The homogeneity tests of risks across the four dose-groups revealed that the RRs for diseases of digestive system and for liver cirrhosis were significantly different, P values being 0.01 and 0.04,respectively.The ERR(95%CI)/Sv for diseases of digestive system and liver cirrhosis were 2.18(0.22,7.64)and 10.94(1.34,NA),respectively. Conclusion The death rates from diseases of digestive system,especially chronic liver diseases and cirrhosis were statistically significantly higher,and that from pulmonary tuberculosis was significantly lower in the HBRA than those in the control area.It is difficult to attribute those risks to chronic natural radiation exposure because of limitations of our data.