title: Cigarette smoking and bladder cancer risk: an evaluation based on a systematic review of epidemiologic evidence in the Japanese population.
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.
authors.affiliation: Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya Department of Urology, Graduate School of Medical Sciences, Kyushu University, Fukuoka.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Masaoka
authors.affiliation: Division of Molecular Medicine, Aichi Cancer Center Research Institute, Nagoya Department of Epidemiology, Nagoya University Graduate School of Medicine, Nagoya kmatsuo@aichi-cc.jp.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Matsuo
authors.affiliation: Department of Epidemiology, Nagoya University Graduate School of Medicine, Nagoya Division of Epidemiology and Prevention, Aichi Cancer Center Research Institute, Nagoya.
authors.forename: Hidemi
authors.initials: H
authors.lastname: Ito
authors.affiliation: Department of Preventive Medicine, Nagoya University Graduate School of Medicine, Nagoya.
authors.forename: Kenji
authors.initials: K
authors.lastname: Wakai
authors.affiliation: Department of Epidemiology and Preventive Medicine, Gifu University Graduate School of Medicine, Gifu.
authors.forename: Chisato
authors.initials: C
authors.lastname: Nagata
authors.affiliation: Center for Cancer Control and Statistics, Osaka Medical Center for Cancer and Cardiovascular Diseases, Osaka.
authors.forename: Tomio
authors.initials: T
authors.lastname: Nakayama
authors.affiliation: Department of Epidemiology, Radiation Effects Research Foundation, Hiroshima.
authors.forename: Atsuko
authors.initials: A
authors.lastname: Sadakane
authors.affiliation: Department of Preventive Medicine, Faculty of Medicine, Saga University, Saga.
authors.forename: Keitaro
authors.initials: K
authors.lastname: Tanaka
authors.affiliation: Department of Public Health, Hokkaido University Graduate School of Medicine, Sapporo.
authors.forename: Akiko
authors.initials: A
authors.lastname: Tamakoshi
authors.affiliation: Division of Epidemiology, Department of Public Health and Forensic Medicine, Tohoku University Graduate School of Medicine, Sendai.
authors.forename: Yumi
authors.initials: Y
authors.lastname: Sugawara
authors.affiliation: Department of Epidemiology and International Health, International Clinical Research Center, National Center for Global Health and Medicine, Tokyo.
authors.forename: Tetsuya
authors.initials: T
authors.lastname: Mizoue
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo.
authors.forename: Norie
authors.initials: N
authors.lastname: Sawada
authors.affiliation: 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.
authors.forename: Manami
authors.initials: M
authors.lastname: Inoue
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo.
authors.forename: Shoichiro
authors.initials: S
authors.lastname: Tsugane
authors.affiliation: Epidemiology and Prevention Division, Research Center for Cancer Prevention and Screening, National Cancer Center, Tokyo.
authors.forename: Shizuka
authors.initials: S
authors.lastname: Sasazuki
mesh_terms: D044466:Asian People / Q000706:statistics & numerical data*; D016022:Case-Control Studies; D015331:Cohort Studies; D015986:Confounding Factors, Epidemiologic; D016021:Epidemiologic Studies; D006801:Humans; D007564:Japan / Q000453:epidemiology; D012107:Research Design; D012307:Risk Factors; D012907:Smoking / Q000009:adverse effects* / Q000453:epidemiology*; D016540:Smoking Cessation; D001749:Urinary Bladder Neoplasms / Q000453:epidemiology* / Q000209:etiology
keywords: Japanese; bladder cancer; cigarette smoking; epidemiology; systematic review