Alavanja M C, Brownson R C, Lubin J H, Berger E, Chang J, Boice J D
Epidemiology and Biostatistics Program, National Cancer Institute, Bethesda, Md 20892.
J Natl Cancer Inst. 1994 Dec 21;86(24):1829-37. doi: 10.1093/jnci/86.24.1829.
Radon at sufficiently high concentrations is known to cause lung cancer among underground miners and in experimental laboratory animals.
Our aim was to determine whether indoor levels of radon are associated with a detectable increase in lung cancer. Nonsmoking women were selected because they offer the best opportunity to detect radon-related risk while minimizing the potentially confounding influences of cigarette smoking and occupation.
A population-based, case-control study of incident lung cancer was conducted in Missouri. A total of 538 non-smoking white women diagnosed with lung cancer between 1986 and 1992 and 1183 age-matched control subjects were identified from the Missouri Cancer Registry and from driver's license and Medicare listings, respectively. Information on lung cancer risk factors was obtained by telephone interview. Year-long radon measurements were sought in every dwelling occupied for the previous 5-30 years.
Radon measurements covered 78% of the relevant residential period, and women reported being indoors for 84% of this time. The time-weighted average radon concentrations were exactly the same for case subjects and control subjects (1.82 pCi/L of air [pCi L-1]). Radon levels greater than 4 pCi L-1 were experienced by 6.5% of the case subjects and 6.8% of the control subjects. For all data combined, there was little evidence for a trend of lung cancer with increasing radon concentrations (two-tailed trend test, P = .99 continuous data analysis; P = .19 categorical data analysis). A positive dose-response trend was suggested for the adenocarcinoma cell type and among directly interviewed women (two-tailed trend test; P = .31 continuous data analysis; P = .04 categorical data analysis), but not for other histologies or among those who had surrogate interviews.
The possibility of detecting a risk from indoor radon in this study was maximized by (a) including a large number of nonsmoking women with high indoor occupancy, (b) conducting a large number of radon measurements near the time of the diagnosis of cancer, and (c) controlling for known causes of lung cancer. However, an association between lung cancer and the exposure to domestic levels of radon was not convincingly demonstrated.
The magnitude of the lung cancer risk from radon levels commonly found in U.S. dwellings appears low.
已知浓度足够高的氡会导致地下矿工和实验室内动物患肺癌。
我们的目的是确定室内氡水平是否与可检测到的肺癌增加有关。选择不吸烟女性是因为她们提供了检测氡相关风险的最佳机会，同时将吸烟和职业的潜在混杂影响降至最低。
在密苏里州进行了一项基于人群的肺癌病例对照研究。分别从密苏里州癌症登记处以及驾照和医疗保险名单中确定了1986年至1992年间被诊断患有肺癌的538名不吸烟白人女性和1183名年龄匹配的对照对象。通过电话访谈获取肺癌危险因素信息。对之前居住5至30年的每一处住所进行为期一年的氡测量。
氡测量覆盖了78%的相关居住期，女性报告在此期间84%的时间待在室内。病例组和对照组的时间加权平均氡浓度完全相同（空气氡浓度为1.82皮居里/升[pCi/L]）。6.5%的病例组对象和6.8%的对照组对象经历过氡水平大于4 pCi/L的情况。综合所有数据，几乎没有证据表明肺癌风险随氡浓度增加而呈趋势变化（双尾趋势检验，连续数据分析P = 0.99；分类数据分析P = 0.19）。对于腺癌细胞类型以及直接接受访谈的女性，显示出正的剂量反应趋势（双尾趋势检验；连续数据分析P = 0.31；分类数据分析P = 0.04），但对于其他组织学类型或接受替代访谈的女性则未显示出该趋势。
本研究通过以下方式最大化了检测室内氡风险的可能性：（a）纳入大量室内居住时间长的不吸烟女性；（b）在癌症诊断时间附近进行大量氡测量；（c）控制已知的肺癌病因。然而，肺癌与家庭环境中氡暴露之间的关联并未得到令人信服的证明。
在美国住宅中常见的氡水平导致肺癌的风险程度似乎较低。
