TY - JOUR
T1 - A case-control study of lung cancer in relation to silica exposure and silicosis in a rural area in Japan
AU - Tsuda, Toshihide
AU - Mino, Yoshio
AU - Babazono, Akira
AU - Shigemi, Jun
AU - Otsu, Tadahiro
AU - Yamamoto, Eiji
AU - Kanazawa, Susumu
N1 - Funding Information:
We greatly thank the relatives of the patients, the doctors, the hospitals, and the clinics in Okayama Prefecture, which provided information for the research on the patients who died in the Tobi Area. We also thank the Tobi Health Center, Okayama Prefectural Government, and the Statistics and Information Department, Minister's Secretariat, Ministry of Health and Welfare. We are grateful to Prof. David F. Goldsmith (George Washington University) and Ms. Faye L. Rice (NIHOSH) for providing very helpful suggestions and information to us. This research was supported by the Ministry of Education (Monbusho Grant-in-Aid for Scientific Research in 1994, 1996, 1997, and 1998). The main findings of the present study were demonstrated in the Ninth International Conference on Occupational Respiratory Diseases, held on October 13–16, 1997, in Kyoto, Japan. The data provided here have been improved by characterizing better the exposure assessment, so the estimates were little different from the previous presentation.
Copyright:
Copyright 2008 Elsevier B.V., All rights reserved.
PY - 2002
Y1 - 2002
N2 - PURPOSE: In southeast Okayama Prefecture, Japan, there have been reports of a high prevalence of silicosis among refractory brick production workers. Recently, a high mortality rate of lung cancer among the local residents has been observed. Therefore, a population based case-control study was conducted concerning the relationship between silica, silicosis, and lung cancer using multiple cancer controls. METHODS: Cases and controls were restricted to male subjects and information was obtained from death certificates from 1986 to 1993 in the area. Three categories of deceased control groups were selected: a series of deaths from liver cancer, colon cancer, and cancers of other organs, which was 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 to control potential confounding factors; such as age and smoking habits. RESULTS: The age-, smoking-adjusted odds ratios were 1.94 (0.94-4.43) for the colon cancer control group, 2.13 (1.19-3.85) for the other cancer control group related to silica exposure, and 2.94 (1.30-8.90) and 2.69 (1.43-5.37) related to silicosis, respectively. The direct weighted average using the estimates for colon and the other cancer controls was 2.06 (1.29-3.29) for silica exposure, and 2.77 (1.60-4.77) for silicosis. Histological or cytological types of lung cancer cases were obtained from 64.1% of the subjects (118/184). As for the histologic type of lung cancer, small cell carcinoma was higher among those who had been silica-exposed workers than the unexposed lung cancer cases and the data from the general Japanese population. On chest x-ray findings, elevated lung cancer mortality compared with cancers other than lung cancer was demonstrated among patients without large opacities. CONCLUSIONS: Silica exposure increased the lung cancer mortality in the area. A high lung cancer mortality rate in the area could be explained by silica exposure and silicosis prevalence in this area.
AB - PURPOSE: In southeast Okayama Prefecture, Japan, there have been reports of a high prevalence of silicosis among refractory brick production workers. Recently, a high mortality rate of lung cancer among the local residents has been observed. Therefore, a population based case-control study was conducted concerning the relationship between silica, silicosis, and lung cancer using multiple cancer controls. METHODS: Cases and controls were restricted to male subjects and information was obtained from death certificates from 1986 to 1993 in the area. Three categories of deceased control groups were selected: a series of deaths from liver cancer, colon cancer, and cancers of other organs, which was 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 to control potential confounding factors; such as age and smoking habits. RESULTS: The age-, smoking-adjusted odds ratios were 1.94 (0.94-4.43) for the colon cancer control group, 2.13 (1.19-3.85) for the other cancer control group related to silica exposure, and 2.94 (1.30-8.90) and 2.69 (1.43-5.37) related to silicosis, respectively. The direct weighted average using the estimates for colon and the other cancer controls was 2.06 (1.29-3.29) for silica exposure, and 2.77 (1.60-4.77) for silicosis. Histological or cytological types of lung cancer cases were obtained from 64.1% of the subjects (118/184). As for the histologic type of lung cancer, small cell carcinoma was higher among those who had been silica-exposed workers than the unexposed lung cancer cases and the data from the general Japanese population. On chest x-ray findings, elevated lung cancer mortality compared with cancers other than lung cancer was demonstrated among patients without large opacities. CONCLUSIONS: Silica exposure increased the lung cancer mortality in the area. A high lung cancer mortality rate in the area could be explained by silica exposure and silicosis prevalence in this area.
KW - Cancer Mortality
KW - Case-Control Study
KW - Lung Neoplasm
KW - Pneumoconiosis
KW - Refractory Brick Workers
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U2 - 10.1016/S1047-2797(01)00271-X
DO - 10.1016/S1047-2797(01)00271-X
M3 - Article
C2 - 12062914
AN - SCOPUS:0036283999
SN - 1047-2797
VL - 12
SP - 288
EP - 294
JO - Annals of Epidemiology
JF - Annals of Epidemiology
IS - 5
ER -
