Hiroyuki Masaoka1, Keitaro Matsuo2, Hidemi Ito3, Kenji Wakai4, Chisato Nagata5, Tomio Nakayama6, Atsuko Sadakane7, Keitaro Tanaka8, Akiko Tamakoshi9, Yumi Sugawara10, Tetsuya Mizoue11, Norie Sawada12, Manami Inoue13, Shoichiro Tsugane12, Shizuka Sasazuki12. 1. Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka. 2. Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya Department of Epidemiology, Nagoya University Graduate School of Medicine, Nagoya kmatsuo@aichi-cc.jp. 3. Department of Epidemiology, Nagoya University Graduate School of Medicine, Nagoya Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya. 4. Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya. 5. Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu. 6. Center for Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka. 7. Department of Epidemiology, Radiation Effects Research Foundation, Hiroshima. 8. Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga. 9. Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo. 10. Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai. 11. Department of Epidemiology and International Health, International Clinical Research Center, National Center for Global Health and Medicine, Tokyo. 12. Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo. 13. Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo AXA Department of Health and Human Security, Graduate School of Medicine, University of Tokyo, Tokyo, Japan.
Abstract
OBJECTIVE: Although several epidemiological studies have demonstrated that cigarette smoking is an important risk factor for bladder cancer, no systematic review in the Japanese population has yet been performed. Accurate evaluation of bladder cancer risk in relation to smoking for Japanese populations can provide necessary information for Japanese policy-makers and doctors to enlighten the importance of smoking cessation. We reviewed epidemiologic data to estimate the strength of the association between cigarette smoking and bladder cancer in the Japanese population. METHODS: We identified previous cohort and case-control studies, extracting data from databases in the MEDLINE (PubMed) and Ichushi. The magnitude of association and strength of evidence were evaluated in each study, and a meta-analysis was conducted to obtain summary estimates for the overall magnitude of association. RESULTS: Three cohort and eight case-control studies were identified. Except for one case-control study, all studies showed a strong positive association between cigarette smoking and bladder cancer. The summary relative risk for ever smokers relative to never smokers was 2.14 (95% confidence interval 1.87-2.44) in a fixed-effect model. CONCLUSIONS: We conclude that cigarette smoking is a convincing risk factor for bladder cancer among Japanese.
OBJECTIVE: Although several epidemiological studies have demonstrated that cigarette smoking is an important risk factor for bladder cancer, no systematic review in the Japanese population has yet been performed. Accurate evaluation of bladder cancer risk in relation to smoking for Japanese populations can provide necessary information for Japanese policy-makers and doctors to enlighten the importance of smoking cessation. We reviewed epidemiologic data to estimate the strength of the association between cigarette smoking and bladder cancer in the Japanese population. METHODS: We identified previous cohort and case-control studies, extracting data from databases in the MEDLINE (PubMed) and Ichushi. The magnitude of association and strength of evidence were evaluated in each study, and a meta-analysis was conducted to obtain summary estimates for the overall magnitude of association. RESULTS: Three cohort and eight case-control studies were identified. Except for one case-control study, all studies showed a strong positive association between cigarette smoking and bladder cancer. The summary relative risk for ever smokers relative to never smokers was 2.14 (95% confidence interval 1.87-2.44) in a fixed-effect model. CONCLUSIONS: We conclude that cigarette smoking is a convincing risk factor for bladder cancer among Japanese.