Tobacco Smoking and Gastric Cancer Risk: An Evaluation Based on a Systematic Review of Epidemiologic Evidence among the Japanese Population (original) (raw)
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Japanese Journal of Clinical Oncology, 2006
Background: It is unclear whether tobacco smoking is related to colorectal cancer risk in Japan. We evaluated the association among the Japanese population based on a systematic review of epidemiologic evidence. Methods: Original data were obtained from searches of MEDLINE using PubMed, complemented with manual searches. The evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility as previously evaluated by the International Agency for Research on Cancer. Results: A total of six cohort studies and 15 case-control studies were thus identified. A substantial degree of heterogeneity was observed in the association between smoking and colon cancer; most case-control studies published before 1994 reported an inverse association, whereas studies conducted over the last decade did not find any significant association. Recent cohort studies have shown a non-significant 20-40% increase in colon cancer risk associated with current smoking. Several recent case-control studies and some cohort studies have identified a weak to strong positive association between smoking and rectal cancer. Conclusion: We conclude that tobacco smoking possibly increases the risk of colorectal cancer among the Japanese population. More specifically, tobacco smoking may possibly increase the risk of rectal cancer; however, epidemiologic evidence is still insufficient to demonstrate any clear association with colon cancer.
Smoking and Colorectal Cancer in a Non-Western Population: a Prospective Cohort Study in Japan
Journal of Epidemiology, 2003
for the JACC Study Group. BACKGROUND: The risk of colorectal cancer in relation to smoking habits has been examined mostly in Caucasians, and evidence for other ethnic groups is still scarce. METHODS: Our data came from the Japan Collaborative Cohort (JACC) Study. From 1988 through 1990, 25,260 men and 34,619 women aged 40-79 years completed a questionnaire on cigarette smoking and other lifestyle factors. Hazard ratios (HR) were estimated by fitting proportional hazards models. RESULTS: During the mean follow-up of 7.6 years through December 1997, we documented 408 incident colon cancers and 204 rectal cancers. We found a non-significant increase in colon cancer risk in male current smokers compared with never smokers. The multivariate-adjusted hazard ratios were 1.07 (95% confidence interval [CI]: 0.72-1.59) for ex-smokers and 1.23 (95% Cl: 0.85-1.78) for current smokers. We however failed to observe a clear dose-response relationship between smoking intensity or duration and colon cancer risk. The adjusted hazard ratio was 1.07 (95% Cl: 0.71-1.61) even for 40+ years of smoking. Almost no increase in colon cancer risk was detected for female smokers, and male smokers were not at an enhanced risk of rectal cancer. CONCLUSIONS: Cigarette smoking was not a strong risk factor for colorectal cancer even after a long-term exposure, although a weak association remains open to discussion.
Smoking and colorectal cancer: A pooled analysis of 10 population‐based cohort studies in Japan
International Journal of Cancer, 2020
Smoking has been consistently associated with the risk of colorectal cancer (CRC) in Western populations; however, evidence is limited and inconsistent in Asian people. To assess the association of smoking status, smoking intensity and smoking cessation with colorectal risk in the Japanese population, we performed a pooled analysis of 10 population-based cohort studies. Study-specific hazard ratios (HRs) and 95% confidence intervals (CIs) were estimated using Cox's proportional hazards model and then pooled using a random-effects model. Among 363 409 participants followed up for 2 666 004 person-years, 9232 incident CRCs were identified. In men, compared with never smokers, ever smokers showed higher risk of CRC. The HRs (95% CI) were
Japanese Journal of Clinical Oncology, 2005
Background: We evaluated the association between tobacco smoking and total cancer risk among Japanese populations based on a systematic review of epidemiological evidence. Methods: Original data were obtained from searches of MEDLINE using PubMed, complemented with manual searches. Evaluation of associations was based on the strength of evidence and the magnitude of association, together with biological plausibility as previously evaluated by the International Agency for Research on Cancer. Meta-analysis of associations was also conducted to obtain summary estimates of association. Results: A total of eight cohort studies were identified. In men, all studies consistently showed a moderately increased risk of total cancer in current smokers compared with never-smokers. In women, an increase in risk was seen but was weaker than in men. The summary relative risk was estimated as 1.53 (95% confidence interval 1.41-1.65). Conclusion: We conclude that there is convincing evidence that current tobacco smoking moderately increases the risk (1.5 times) of total cancer in the Japanese population compared with never-smoking Japanese.
Japanese Journal of Clinical Oncology, 2012
Objective: Although cigarette smoking is considered as an important risk factor for esophageal cancer, the magnitude of the association might be varied among geographic areas. Therefore, we reviewed epidemiologic studies on the association between cigarette smoking and esophageal cancer among the Japanese population. Methods: Original articles were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented by manual searches. Evaluation of associations was based on the strength of evidence ('convincing', 'probable', 'possible' or 'insufficient') and the magnitude of association ('strong', 'moderate', 'weak' or 'no association'), together with biological plausibility as previously evaluated by the International Agency for Research on Cancer. Results: We identified four cohort studies and 11 case -control studies. All cohort studies and eight case -control studies showed strong positive associations between esophageal cancer and cigarette smoking. All cohort studies and five case -control studies showed that cigarette smoking had dose -response relationships with esophageal cancer. Metaanalysis of 12 studies indicated that the summary estimate for ever smokers relative to never smokers was 3.01 (95% confidence interval: 2.30 -3.94). Summary relative risk for current and former smokers relative to never smokers was 3.73 (2.16 -6.43) and 2.21 (1.60 -3.06), respectively. Conclusions: We conclude that there is convincing evidence that cigarette smoking strongly increases the risk of esophageal cancer in the Japanese population.
Smoking and Colorectal Cancer: A Meta-analysis
Jama-journal of The American Medical Association, 2008
Context Colorectal cancer is the third most common form of cancer and the fourth most frequent cause of cancer deaths worldwide. The association between cigarette smoking and colorectal cancer has been inconsistent among studies.
International Journal of Environmental Research and Public Health, 2009
Although smoking is an established causal factor for upper aero digestive tract cancer (UADTC), most of the evidence originates from the West. Thus, we analysed data from 455,409 subjects in the Asia Pacific Cohort Studies Collaboration. Over a median of around six years follow-up, 371 deaths from UADTC were observed. The hazard ratio (95% confidence interval) for current smokers, compared with those who had never smoked, was 2.36 (1.76 -3.16), adjusted for age and alcohol drinking. Tobacco control policies are urgently required in Asia to prevent millions of deaths from UADTC that smoking will otherwise cause.
Japanese Journal of Clinical Oncology, 2011
Objective: Cigarette smoking has been recognized as an important risk factor for pancreas cancer, but the magnitude of the association may vary among geographical areas. Therefore, we reviewed epidemiologic studies on the association between cigarette smoking and pancreas cancer in the Japanese population. Methods: Original data were obtained from MEDLINE searched using PubMed or from searches of the Ichushi database, complemented with manual searches. Evaluation of associations was based on the strength of evidence ('convincing', 'probable', 'possible' or 'insufficient') and the magnitude of association ('strong', 'moderate', 'weak' or 'no association'), together with biological plausibility as previously evaluated by the International Agency of Research on Cancer. Results: We identified four cohort studies and three case-control studies. All cohort studies consistently showed positive associations between pancreas cancer and cigarette smoking, although statistical significance in each study is variable. Most of the cohort studies consistently showed that cigarette smoking had a dose-response relationship with pancreas cancer. One case-control study showed a strong positive association, but the rest did not show any association. Meta-analysis of seven studies indicated that a summary estimate for ever smoking relative to never smoking was 1.68 (95% confidence interval: 1.38-2.05). Conclusions: We conclude that there is convincing evidence that cigarette smoking moderately increases the risk of pancreas cancer in the Japanese population.
Cigarette smoking and mortality due to stomach cancer: Findings from the JACC study
Journal of Epidemiology, 2005
Data Retrieval for Analysis In order to identify the appropriate data for our analysis, we first restricted the dataset to include only those subjects who lacked a previous history of any type of cancer (n = 109,313). Our analysis was then further limited to the 98,062 participants (43,482 male and 54,580 female) who provided sufficient information about their smoking habits. Cigarette Smoking and Other Factors The questionnaire required participants to indicate their smoking status as 'non-smoker', 'past smoker', or 'current smoker'. For smokers, the number of cigarettes smoked per day was also recorded. The total number of 'cigarette-years' for smokers was calculated by multiplying the number of cigarettes smoked per day by the duration (years) of smoking. The following baseline characteristics, which might be related to stomach cancer, were also considered: age (5-year categories); alcohol consumption 9,19 ('current habitual drinker', 'previous habitual drinker' or 'teetotal'); consumption of green tea 20 ('almost every day', 'three times or more per week', or 'less than three times per week'); preference for salty foods 21-23 ('like salty foods', 'neutral towards salty foods' or 'dislike salty foods'); and educational level 15,24,25 ('attended school beyond the age of 18 years', 'attended school until the age of 16-17 years' or 'attended school until the age of 15 years or below'). Statistical Analysis The Cox proportional-hazards regression model was used to estimate the hazard risk (HR) of smoking for mortality due to stomach cancer, while adjusting for the potential confounding factors listed above. Missing values in each variable were treated as an additional category in the analysis. All calculations were performed using the Statistical Analysis System ®. 26
Cigarette Smoking and Gastric Cancer Risk in a Community-based Cohort Study in Korea
Journal of Preventive Medicine and Public Health, 2007
Objectives : Gastric cancer is the most common incident cancer in Korea. Although Helicobacter pylori infection is the most important risk factor for the development of gastric cancer, cigarette smoking has also been suggested to play an important role in the development of gastric cancer. The objective of this study is to evaluate the relationship between cigarette smoking and gastric cancer risk in a Korean population. Methods : The study population consisted of 13,785 subjects who had been enrolled in the Korean Multi-Center Cancer Cohort between 1993 and 2002. As of December 2002, 139 incident gastric cancer cases were ascertained through the Korea Central Cancer Registry and the National Death Certificate Database. Relative risks (RR) and 95% confidence intervals (CI) for gastric cancer were estimated using CoxV s proportional hazard model adjusted for age, education, alcohol drinking status and history of gastritis or ulcer. Results : Significant dose-response relationships were observed between the duration of smoking and the risk of gastric cancer among the male subjects in comparison to non-smokers: men who smoked for 20-39 years had a 2.09fold (95% CI 1.00-4.38) increase, and those who smoked for more than 40 years had a 3.13-fold (95% CI 1.59-6.17) increase in the risk of gastric cancer (Ptrend<0.01). Conclusions : This study suggests that a longer duration of cigarette smoking may increase the risk of gastric cancer development in a dose-response manner in Korean men. The association between smoking and gastric cancer risk in women should be verified in future studies with a larger number of cases.