室内氡与肺癌关系研究

Relation between indoor radon and lung cancer

目的 直接调查居室水平氡浓度对居民肺癌危险度的影响 ,并与由矿工受照结果推导的结论相比较。方法 在甘肃省平凉、庆阳两地区进行病例 对照研究。该地区居民稳定而室内氡水平较高。肺癌病例必须是在 1994年 1月至 1998年 4月期间诊断 ,年龄在 30～ 75岁之间 ,居住在平凉和庆阳两地区的居民。根据人口调查资料随机选取对照 ,对照要在年龄、性别、地区方面与病例相匹配。在过去 5～ 30年期间 ,凡住过两年以上的房间都布放了氡探测器。氡测量涵盖了 77%的照射周期。结果 病例居室的平均氡浓度为 2 30 4Bq m3 (n =76 8) ,对照为 2 2 2 2Bq m3 (n =16 5 9)。居民肺癌危险度随室内氡水平的增高有所上升 (P <0 0 0 1)。根据线性模型 ,对全部研究个体而言 ,在 10 0Bq m3 情况下 ,附加比值比 (EOR)为 0 19(95 %CI:0 0 5 ,0 47)。对测量涵盖了 10 0 %照射周期的个体 ,为 0 31(95 %CI:0 10 ,0 81)。在对照射的不确定度进行调整后 ,估算值可增加70 %。结论 研究结果证明室内水平氡照射会增加肺癌危险度 。

Objective\ Low level of exposures to residential radon and dosimetric uncertainties due to mobility have hampered the evaluation of lung cancer risk and the comparison to radon\|exposed miners.To address these limitations,the authors conducted a case\|control study in a predominantly rural area of China with low mobility and high radon levels. Methods\ Cases studied including all lung cancer patients diagnosed between Ja nuary 1994 and April 1998,aged 30\|75 years,and resided in two prefectures of Gansu Province.Controls were randomly selected from census lists and matched on age sex and prefecture.Radon detectors were placed in all houses having been occupied two or more years in the past 5\|30 years prior to enrollment.Measurements covered 77% of the possible exposure time. Results\ Mean radon concentrations were 230 4 Bq/m\+3 for the cases( n =768) and 222.2 Bq/m\+3 for the controls( n =1 659).Lung cancer risk increased along with increase of the radon level( P <0.001).Based on a linear model,the excess odds ratio(EOR)at 100 Bq/m\+3 was 0.19(95% CI:0.05,0 47)for all subjects,and 0.31(95%CI:0.10,0.81)for subjects with 100% coverage of the exposure interval.Adjusting for exposure uncertainties increased estimates about 70%. Conclusion\ The results support increased lung cancer risks with indoor radon exposures,which may equal to or exceed extrapolation\|based risks from miner data.