An Epidemiologic Study on an Excess Risk of Lung Cancer in the Southeast Area of Okayama Prefecture, Japan

在日本冈山县东南部，有报道称耐火砖生产工人矽肺患病率高，居民患肺癌的风险过高。因此，本研究以人群为基础，对矽肺、矽肺和肺癌之间的关系进行了病例对照研究，研究对象为1986~1993年死亡证明中的男性。选择了四种死亡对照组：一系列死于肝癌、结肠癌和其他器官癌症，假定与二氧化硅接触无关。年龄和吸烟习惯通过分层分析调整，使用Mantel-Haenszel优势比估计。非条件Logistic回归分析也控制了潜在的混杂因素，如年龄和吸烟习惯。年龄、吸烟调整后的优势比分别为1.59(0.87-3.03)和1.94(0.94-4.43)结肠癌…矽肺对照组分别为2.45(1.22~5.34)、2.94(1.30~8.90)、2.69(1.43~5.37)。肺癌组织学或细胞学分型占64.1%(118/184)。在肺癌的组织学类型上，与未暴露的肺癌病例和普通日本人的数据进行比较后，小细胞癌可能与接触二氧化硅有关。胸部X光检查结果显示，与肺癌以外的其他癌症相比，在无大阴影的患者中，肺癌死亡率升高。矽肺暴露增加了该地区的肺癌死亡率。这一结果支持了国际癌症研究机构在1997年提出的二氧化硅暴露与肺癌之间的因果关系。从现在起，二氧化硅接触与食道癌、胃癌、肝癌的关系。血液系统恶性肿瘤，据报道与二氧化硅接触有关，应进行调查和检查。较少

In the south east of Okayama Prefecture, Japan, there have been reports on high prevalence of silicosis among refractory brick production workers, and excess risk of lung cancer among the residents. Therefore, a population based case-control study was conducted on the relationship between silica, silicosis, and lung cancer.Cases and controls were restricted to male subjects and obtained from death certificates from 1986 to 1993 in the area. Four kinds of deceased control groups were selected ; the series of deaths from liver cancer, colon cancer, and cancers of the other organs, which assumed not to be related to silica exposure. Age and smoking habits were adjusted by stratified analysis using the Mantel-Haenszel odds ratio estimates. Unconditional logistic regression analysis was also conducted for controlling potential confounding factors ; such as age and smoking habits.The age-, smoking-adjusted odds ratios were 1.59 (0.87-3.03) for liver cancer control, 1.94 (0.94-4.43) for colon … More cancer control, and 2.13 (1.19-3.85) for the other cancer control on silica exposure, and 2.45 (1.22-5.34), 2.94 (1.30-8.90), and 2.69 (1.43-5.37) on silicosis, respectively. Histologic or cytologic types of lung cancer cases were obtained from 64.1% (118/184). On histologic types of lung cancer, small cell carcinoma may related to silica exposure after comparing with unexposed lung cancer cases and the data from the general Japanese population. On the findings of chest X-ray, elevated lung cancer mortality compared with other cancers than lung was demonstrated among the patients without large opacities.Silica exposure increased the lung cancer mortality in the area. The results support the causal relationship between silica exposure and lung cancer, designated by IARC in 1997. From now, the relationship between silica exposure and esophagus cancer, gastric cancer, liver cancer. and hematopoietic malignancy which has been reported the association to silica exposure should be investigated and examined. Less