In this paper,we investigate the weighted Dirichlet eigenvalue problem of polynomial operator of the drifting Laplacian on the cigar soliton■as follows■where is a positive continuous function on,denotes the outward ...In this paper,we investigate the weighted Dirichlet eigenvalue problem of polynomial operator of the drifting Laplacian on the cigar soliton■as follows■where is a positive continuous function on,denotes the outward unit normal to the boundary,and are two nonnegative constants.We establish some universal inequalities for eigenvalues of this problem.展开更多
This thesis intends to use the symbolic structure of cigar to analyze the extract Blackmail from Arthur Hailey's short novel Hotel.The function of cigar in Blackmail can be concluded as a) constructive clue of the...This thesis intends to use the symbolic structure of cigar to analyze the extract Blackmail from Arthur Hailey's short novel Hotel.The function of cigar in Blackmail can be concluded as a) constructive clue of the plot progression,b) genteel carrier in making up characters.Rotating around the constructive clue,cigar,the writer of this thesis breaks down the whole story into seven parts,i.e.mystical entrance,prelude,crossfire,preparatory victory,absolute superiority,negotiation (absence of cigar) and discard.As to cigar's function of making up character,this thesis examines it from four main social and historical aspects,i.e.the origin of cigar in history,the social token of cigar,the complicated approaches of using cigar,and the historical stereotypes related to cigar smoking.展开更多
BACKGROUND More recent data are required relating to disease risk for use of various smoked products and of other products containing nicotine.Earlier we published metaanalyses of recent results for chronic obstructiv...BACKGROUND More recent data are required relating to disease risk for use of various smoked products and of other products containing nicotine.Earlier we published metaanalyses of recent results for chronic obstructive pulmonary disease and lung cancer on the relative risk(RR)of current compared to never product use for cigarettes,cigars and pipes based on evidence from North America,Europe and Japan.We now report corresponding up-to-date evidence for acute myocardial infarction(AMI),ischaemic heart disease(IHD)and stroke.AIM To estimate,using recent data,AMI,IHD and stroke RRs by region for current smoking of cigarettes,cigars and pipes.METHODS Publications in English from 2015 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of AMI,IHD or stroke for one or more of the three products.The studies should involve at least 100 cases of stroke or cardiovascular disease(CVD),not be restricted to populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.A literature search was conducted on MEDLINE,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and meta-analyses.For each study identified,we entered the most recent available data on current smoking of each product,as well as the characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis for stroke and,in the case of CVD,separately for IHD and AMI.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.A more limited assessment of variation in risk by daily number of cigarettes smoked was also conducted.RESULTS Current cigarette smoking:Ten studies gave a random-effects RR for AMI of 2.72[95%confidence interval(CI):2.40-3.08],derived from 13 estimates between 1.47 and 4.72.Twenty-three studies gave an IHD RR of 2.01(95%CI:1.84-2.21),using 28 estimates between 0.81 and 4.30.Thirty-one studies gave a stroke RR of 1.62(95%CI:1.48-1.77),using 37 estimates from 0.66 to 2.91.Though heterogeneous,only two of the overall 78 RRs were below 1.0,71 significantly(P<0.05)exceeding 1.0.The heterogeneity was only partly explicable by the factors studied.Estimates were generally higher for females and for later-starting studies.They were significantly higher for North America than Europe for AMI,but not the other diseases.For stroke,the only endpoint with multiple Japanese studies,RRs were lower there than for Western studies.Adjustment for multiple factors tended to increase RRs.Our RR estimates and the variations by sex and region are consistent with earlier meta-analyses.RRs generally increased with amount smoked.Current cigar and pipe smoking:No AMI data were available.One North American study reported reduced IHD risk for non-exclusive cigar or pipe smoking,but considered few cases.Two North American studies found no increased stroke risk with exclusive cigar smoking,one reporting reduced risk for exclusive pipe smoking(RR 0.24,95%CI:0.06-0.91).The cigar results agree with an earlier review showing no clear risk increase for IHD or stroke.CONCLUSION Current cigarette smoking increases risk of AMI,IHD and stroke,RRs being 2.72,2.01 and 1.62.The stroke risk is lower in Japan,no increase was seen for cigars/pipes.展开更多
BACKGROUND There is a need to have up-to-date information for various diseases on the risk related to the use of different smoked products and the use of other nicotinecontaining products.Here,we contribute to the inf...BACKGROUND There is a need to have up-to-date information for various diseases on the risk related to the use of different smoked products and the use of other nicotinecontaining products.Here,we contribute to the information pool by presenting up-to-date quantitative evidence for North America,Europe and Japan and for both lung cancer and chronic obstructive pulmonary disease(COPD)on the relative risk(RR)relating to current vs never product use for each of the three smoked tobacco products,cigarettes,cigars and pipes.AIM To estimate lung cancer and COPD current smoking RRs for the three products using recent data for the three regions.METHODS Publications in English from 2010 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of lung cancer and/or COPD for one or more of the three products.The studies should involve at least 100 cases of the disease considered,not be restricted to specific lung cancer types or populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.Literature searches were conducted on MEDLINE separately for lung cancer and for COPD,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and metaanalyses.For each study identified,the most recent available data on each product were entered on current smoking,as well as on characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.Results were compared with those from previous meta-analyses published since 2000.RESULTS Current cigarette smoking:For lung cancer,44 studies(26 North American,14 European,three Japanese,and one in multiple continents),gave an overall estimate of 12.14[95%confidence interval(CI)10.30-14.30].The estimates were higher(heterogeneity P<0.001)for North American(15.15,CI 12.77-17.96)and European studies(12.30,CI 9.77-15.49)than for Japanese studies(3.61,CI 2.87-4.55),consistent with previous evidence of lower RRs for Asia.RRs were higher(P<0.05)for death(14.85,CI 11.99-18.38)than diagnosis(10.82,CI 8.61-13.60).There was some variation(P<0.05)by study population,with higher RRs for international and regional studies than for national studies and studies of specific populations.RRs were higher in males,as previously reported,the within-study male/female ratio of RRs being 1.52(CI 1.20-1.92).RRs did not vary significantly(P≥0.05)by other factors.For COPD,RR estimates were provided by 18 studies(10 North American,seven European,and one Japanese).The overall estimate of 9.19(CI 6.97-12.13),was based on heterogeneous data(P<0.001),and higher than reported earlier.There was no(P>0.1)variation by sex,region or exclusive use,but limited evidence(0.05<P<0.1)that RR estimates were greater where cases occurring shortly after baseline were ignored;where bronchiectasis was excluded from the COPD definition;and with greater confounder adjustment.Within-study comparisons showed adjusted RRs exceeded unadjusted RRs.Current cigar smoking:Three studies gave an overall lung cancer RR of 2.73(CI 2.36-3.15),with no heterogeneity,lower than the 4.67(CI 3.49-6.25)reported in an earlier review.Only one study gave COPD results,the RR(2.44,CI 0.98-6.05)being imprecise.Current pipe smoking:Four studies gave an overall lung cancer RR of 4.93(CI 1.97-12.32),close to the 5.20(CI 3.50-7.73)given earlier.However,the estimates were heterogeneous,with two above 10,and two below 3.Only one study gave COPD results,the RR(1.12,CI 0.29-4.40),being imprecise.For both diseases,the lower RR estimates for cigars and for pipes than for current smoking of cigarettes aligns with earlier published evidence.CONCLUSION Current cigarette smoking substantially increases lung cancer and COPD risk,more so in North America and Europe than Japan.Limited evidence confirms lower risks for cigars and pipes than cigarettes.展开更多
Elevation affects the contents of polyphenols involved in the plants’resistance to the environment.In this study,polyphenolic contents,as well as the activity of polyphenol oxidase(PPO),were evaluated in mature cigar...Elevation affects the contents of polyphenols involved in the plants’resistance to the environment.In this study,polyphenolic contents,as well as the activity of polyphenol oxidase(PPO),were evaluated in mature cigar plants at different elevation levels.The results showed that:(1)The contents of chlorogenic acid,rutin,and scopolamine in cigar leaves increased gradually at all elevation levels,reaching a maximum 25 d after the mature stage.(2)With an increase in altitude,the polyphenolic compounds’contents increased,having the lowest values at 350 m height and the highest at 1090 m height.(3)As for the PPO activity in cigar leaves,the general trend showed an increase first followed by a decrease in activity during the mature period.(4)PPO activity in the leaves of cigar plants planted at 840 m height was substantially elevated compared to those growing at 600 m and 350 m height.Interestingly,the leaves planted at 1090 m height had the lowest PPO activity.(5)There were significant positive correlations between altitude and the contents of chlorogenic acid,rutin,and scopolamine within the plants leaves.Altitude negatively correlated the proportion of chlorogenic acid and scopolamine whereas positively correlated rutin proportion within the total polyphenols.Temperature had negative correlations with the contents of chlorogenic acid,rutin,and scopolamine,while sunlight intensity had positive correlations on their contents.Conversely,there were no significant correlations between altitude,temperature,and light intensity on PPO activity.Therefore,this study can provide valuable insight and a theoretical basis for the production of premium cigars.展开更多
Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally.Cigarette factories are a key link in ...Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally.Cigarette factories are a key link in the tobacco industry’s production chain,and using data provided by a cigarette factory in China we conduct a life cycle assessment to account for the carbon footprint of cigar production in cigarette factories.The results of the assessment show that factory air conditioning is the most important contributor to the environmental load of the cigar manufacturing process,while electricity is the key factor that contributes the greatest envi‐ronmental load across all of the processes in the product life cycle.In addition,packaging,including small boxes and cigarette cartons,has a significant impact on the industry’s environmental footprint due to its use of raw materials.We find the carbon footprint of the entire production process for cigar products to be 383.59 kg CO_(2) eq.Based on our findings,we suggest ways to optimize cigar/cigarette factory processes to re‐duce carbon emissions that can help to promote sustainable development in related industries.展开更多
BACKGROUND Little information has been published on the risks of cigar smoking.Since 1990 cigar smoking has become more prevalent in the United States.AIM To summarise the evidence from the United States relating excl...BACKGROUND Little information has been published on the risks of cigar smoking.Since 1990 cigar smoking has become more prevalent in the United States.AIM To summarise the evidence from the United States relating exclusive cigar smoking to risk of the major smoking-related diseases.METHODS Literature searches detected studies carried out in the United States which estimated the risk of lung cancer,chronic obstructive pulmonary disease(COPD),heart disease,stroke or overall circulatory disease in exclusive cigar smokers as compared to those who had never smoked any tobacco product.Papers were identified from reviews and detailed searches on MEDLINE.For each study,data were extracted onto a study database and a linked relative risk database.Relative risks and 95%CIs were extracted,or estimated,relating to current,former or ever exclusive cigar smokers,and meta-analysed using standard methods.Sensitivity analyses were conducted including or excluding results from studies that did not quite fit the full selection criteria(for example,a paper presenting combined results from five studies,where 86%of the population were in the United States).RESULTS The literature searches identified 17 relevant publications for lung cancer,four for COPD and 12 for heart disease,stroke and circulatory disease.These related to 11 studies for lung cancer,to four studies for COPD and to eight studies for heart disease,stroke or overall circulatory disease.As some studies provided results for more than one disease,the total number of studies considered was 13,with results from four of these used in sensitivity analyses.There was evidence of significant heterogeneity in some of the meta-analyses so the random-effects estimates are summarized below.As the results from the sensitivity analyses were generally very similar to those from the main analyses,and involved more data,only the sensitivity results are summarized below.For lung cancer,relative risks(95%CI)for current,former and ever smokers were respectively,2.98(2.08 to 4.26),1.61(1.23 to 2.09),and 2.22(1.79 to 2.74)based on 6,4 and 10 individual study estimates.For COPD,the corresponding estimates were 1.44(1.16 to 1.77),0.47(0.02 to 9.88),and 0.86(0.48 to 1.54)based on 4,2 and 2 estimates.For ischaemic heart disease(IHD)the estimates were 1.11(1.04 to 1.19),1.26(1.03 to 1.53)and 1.15(1.08 to 1.23)based on 6,3 and 4 estimates,while for stroke they were 1.02(0.92 to 1.13),1.08(0.85 to 1.38),and 1.11(0.95 to 1.31)based on 5,3 and 4 estimates.For overall circulatory disease they were 1.10(1.05 to 1.16),1.11(0.84 to 1.46),and 1.15(1.06 to 1.26)based on 3,3 and 4 estimates.CONCLUSION Exclusive cigar smoking is associated with an increased risk of lung cancer,and less so with COPD and IHD.The increases are lower than for cigarettes.展开更多
基金Supported by National Natural Science Foundation of China(11001130,12272062)Fundamental Research Funds for the Central Universities(30917011335).
文摘In this paper,we investigate the weighted Dirichlet eigenvalue problem of polynomial operator of the drifting Laplacian on the cigar soliton■as follows■where is a positive continuous function on,denotes the outward unit normal to the boundary,and are two nonnegative constants.We establish some universal inequalities for eigenvalues of this problem.
文摘This thesis intends to use the symbolic structure of cigar to analyze the extract Blackmail from Arthur Hailey's short novel Hotel.The function of cigar in Blackmail can be concluded as a) constructive clue of the plot progression,b) genteel carrier in making up characters.Rotating around the constructive clue,cigar,the writer of this thesis breaks down the whole story into seven parts,i.e.mystical entrance,prelude,crossfire,preparatory victory,absolute superiority,negotiation (absence of cigar) and discard.As to cigar's function of making up character,this thesis examines it from four main social and historical aspects,i.e.the origin of cigar in history,the social token of cigar,the complicated approaches of using cigar,and the historical stereotypes related to cigar smoking.
文摘BACKGROUND More recent data are required relating to disease risk for use of various smoked products and of other products containing nicotine.Earlier we published metaanalyses of recent results for chronic obstructive pulmonary disease and lung cancer on the relative risk(RR)of current compared to never product use for cigarettes,cigars and pipes based on evidence from North America,Europe and Japan.We now report corresponding up-to-date evidence for acute myocardial infarction(AMI),ischaemic heart disease(IHD)and stroke.AIM To estimate,using recent data,AMI,IHD and stroke RRs by region for current smoking of cigarettes,cigars and pipes.METHODS Publications in English from 2015 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of AMI,IHD or stroke for one or more of the three products.The studies should involve at least 100 cases of stroke or cardiovascular disease(CVD),not be restricted to populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.A literature search was conducted on MEDLINE,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and meta-analyses.For each study identified,we entered the most recent available data on current smoking of each product,as well as the characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis for stroke and,in the case of CVD,separately for IHD and AMI.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.A more limited assessment of variation in risk by daily number of cigarettes smoked was also conducted.RESULTS Current cigarette smoking:Ten studies gave a random-effects RR for AMI of 2.72[95%confidence interval(CI):2.40-3.08],derived from 13 estimates between 1.47 and 4.72.Twenty-three studies gave an IHD RR of 2.01(95%CI:1.84-2.21),using 28 estimates between 0.81 and 4.30.Thirty-one studies gave a stroke RR of 1.62(95%CI:1.48-1.77),using 37 estimates from 0.66 to 2.91.Though heterogeneous,only two of the overall 78 RRs were below 1.0,71 significantly(P<0.05)exceeding 1.0.The heterogeneity was only partly explicable by the factors studied.Estimates were generally higher for females and for later-starting studies.They were significantly higher for North America than Europe for AMI,but not the other diseases.For stroke,the only endpoint with multiple Japanese studies,RRs were lower there than for Western studies.Adjustment for multiple factors tended to increase RRs.Our RR estimates and the variations by sex and region are consistent with earlier meta-analyses.RRs generally increased with amount smoked.Current cigar and pipe smoking:No AMI data were available.One North American study reported reduced IHD risk for non-exclusive cigar or pipe smoking,but considered few cases.Two North American studies found no increased stroke risk with exclusive cigar smoking,one reporting reduced risk for exclusive pipe smoking(RR 0.24,95%CI:0.06-0.91).The cigar results agree with an earlier review showing no clear risk increase for IHD or stroke.CONCLUSION Current cigarette smoking increases risk of AMI,IHD and stroke,RRs being 2.72,2.01 and 1.62.The stroke risk is lower in Japan,no increase was seen for cigars/pipes.
文摘BACKGROUND There is a need to have up-to-date information for various diseases on the risk related to the use of different smoked products and the use of other nicotinecontaining products.Here,we contribute to the information pool by presenting up-to-date quantitative evidence for North America,Europe and Japan and for both lung cancer and chronic obstructive pulmonary disease(COPD)on the relative risk(RR)relating to current vs never product use for each of the three smoked tobacco products,cigarettes,cigars and pipes.AIM To estimate lung cancer and COPD current smoking RRs for the three products using recent data for the three regions.METHODS Publications in English from 2010 to 2020 were considered that,based on epidemiological studies in the three regions,estimated the current smoking RR of lung cancer and/or COPD for one or more of the three products.The studies should involve at least 100 cases of the disease considered,not be restricted to specific lung cancer types or populations with specific medical conditions,and should be of cohort or nested case-control study design or randomized controlled trials.Literature searches were conducted on MEDLINE separately for lung cancer and for COPD,examining titles and abstracts initially,and then full texts.Additional papers were sought from reference lists of selected papers,reviews and metaanalyses.For each study identified,the most recent available data on each product were entered on current smoking,as well as on characteristics of the study and the RR estimates.Combined RR estimates were derived using random-effects meta-analysis.For cigarette smoking,where far more data were available,heterogeneity was studied by a wide range of factors.For cigar and pipe smoking,a more limited heterogeneity analysis was carried out.Results were compared with those from previous meta-analyses published since 2000.RESULTS Current cigarette smoking:For lung cancer,44 studies(26 North American,14 European,three Japanese,and one in multiple continents),gave an overall estimate of 12.14[95%confidence interval(CI)10.30-14.30].The estimates were higher(heterogeneity P<0.001)for North American(15.15,CI 12.77-17.96)and European studies(12.30,CI 9.77-15.49)than for Japanese studies(3.61,CI 2.87-4.55),consistent with previous evidence of lower RRs for Asia.RRs were higher(P<0.05)for death(14.85,CI 11.99-18.38)than diagnosis(10.82,CI 8.61-13.60).There was some variation(P<0.05)by study population,with higher RRs for international and regional studies than for national studies and studies of specific populations.RRs were higher in males,as previously reported,the within-study male/female ratio of RRs being 1.52(CI 1.20-1.92).RRs did not vary significantly(P≥0.05)by other factors.For COPD,RR estimates were provided by 18 studies(10 North American,seven European,and one Japanese).The overall estimate of 9.19(CI 6.97-12.13),was based on heterogeneous data(P<0.001),and higher than reported earlier.There was no(P>0.1)variation by sex,region or exclusive use,but limited evidence(0.05<P<0.1)that RR estimates were greater where cases occurring shortly after baseline were ignored;where bronchiectasis was excluded from the COPD definition;and with greater confounder adjustment.Within-study comparisons showed adjusted RRs exceeded unadjusted RRs.Current cigar smoking:Three studies gave an overall lung cancer RR of 2.73(CI 2.36-3.15),with no heterogeneity,lower than the 4.67(CI 3.49-6.25)reported in an earlier review.Only one study gave COPD results,the RR(2.44,CI 0.98-6.05)being imprecise.Current pipe smoking:Four studies gave an overall lung cancer RR of 4.93(CI 1.97-12.32),close to the 5.20(CI 3.50-7.73)given earlier.However,the estimates were heterogeneous,with two above 10,and two below 3.Only one study gave COPD results,the RR(1.12,CI 0.29-4.40),being imprecise.For both diseases,the lower RR estimates for cigars and for pipes than for current smoking of cigarettes aligns with earlier published evidence.CONCLUSION Current cigarette smoking substantially increases lung cancer and COPD risk,more so in North America and Europe than Japan.Limited evidence confirms lower risks for cigars and pipes than cigarettes.
文摘Elevation affects the contents of polyphenols involved in the plants’resistance to the environment.In this study,polyphenolic contents,as well as the activity of polyphenol oxidase(PPO),were evaluated in mature cigar plants at different elevation levels.The results showed that:(1)The contents of chlorogenic acid,rutin,and scopolamine in cigar leaves increased gradually at all elevation levels,reaching a maximum 25 d after the mature stage.(2)With an increase in altitude,the polyphenolic compounds’contents increased,having the lowest values at 350 m height and the highest at 1090 m height.(3)As for the PPO activity in cigar leaves,the general trend showed an increase first followed by a decrease in activity during the mature period.(4)PPO activity in the leaves of cigar plants planted at 840 m height was substantially elevated compared to those growing at 600 m and 350 m height.Interestingly,the leaves planted at 1090 m height had the lowest PPO activity.(5)There were significant positive correlations between altitude and the contents of chlorogenic acid,rutin,and scopolamine within the plants leaves.Altitude negatively correlated the proportion of chlorogenic acid and scopolamine whereas positively correlated rutin proportion within the total polyphenols.Temperature had negative correlations with the contents of chlorogenic acid,rutin,and scopolamine,while sunlight intensity had positive correlations on their contents.Conversely,there were no significant correlations between altitude,temperature,and light intensity on PPO activity.Therefore,this study can provide valuable insight and a theoretical basis for the production of premium cigars.
基金supported by Shandong Natural Science Founda‐tion[Grant No.ZR2023MD079]Shandong Province Social Science Planning Research Project[Grant No.22CKRJ04]+2 种基金Taishan Scholar Project[Grant No.tsqn202103010]Department of Science and Tech‐nology of Shandong Province[Grant No.2021SFGC0904-05]Zaozhuang Science and Technology Bureau[Grant No.2021GH22].
文摘Although the tobacco industry is a significant contributor to energy consumption and carbon emissions its negative environmental impact has received inadequate attention globally.Cigarette factories are a key link in the tobacco industry’s production chain,and using data provided by a cigarette factory in China we conduct a life cycle assessment to account for the carbon footprint of cigar production in cigarette factories.The results of the assessment show that factory air conditioning is the most important contributor to the environmental load of the cigar manufacturing process,while electricity is the key factor that contributes the greatest envi‐ronmental load across all of the processes in the product life cycle.In addition,packaging,including small boxes and cigarette cartons,has a significant impact on the industry’s environmental footprint due to its use of raw materials.We find the carbon footprint of the entire production process for cigar products to be 383.59 kg CO_(2) eq.Based on our findings,we suggest ways to optimize cigar/cigarette factory processes to re‐duce carbon emissions that can help to promote sustainable development in related industries.
基金Supported by the JT International SA,Assignment Schedule,No.14.
文摘BACKGROUND Little information has been published on the risks of cigar smoking.Since 1990 cigar smoking has become more prevalent in the United States.AIM To summarise the evidence from the United States relating exclusive cigar smoking to risk of the major smoking-related diseases.METHODS Literature searches detected studies carried out in the United States which estimated the risk of lung cancer,chronic obstructive pulmonary disease(COPD),heart disease,stroke or overall circulatory disease in exclusive cigar smokers as compared to those who had never smoked any tobacco product.Papers were identified from reviews and detailed searches on MEDLINE.For each study,data were extracted onto a study database and a linked relative risk database.Relative risks and 95%CIs were extracted,or estimated,relating to current,former or ever exclusive cigar smokers,and meta-analysed using standard methods.Sensitivity analyses were conducted including or excluding results from studies that did not quite fit the full selection criteria(for example,a paper presenting combined results from five studies,where 86%of the population were in the United States).RESULTS The literature searches identified 17 relevant publications for lung cancer,four for COPD and 12 for heart disease,stroke and circulatory disease.These related to 11 studies for lung cancer,to four studies for COPD and to eight studies for heart disease,stroke or overall circulatory disease.As some studies provided results for more than one disease,the total number of studies considered was 13,with results from four of these used in sensitivity analyses.There was evidence of significant heterogeneity in some of the meta-analyses so the random-effects estimates are summarized below.As the results from the sensitivity analyses were generally very similar to those from the main analyses,and involved more data,only the sensitivity results are summarized below.For lung cancer,relative risks(95%CI)for current,former and ever smokers were respectively,2.98(2.08 to 4.26),1.61(1.23 to 2.09),and 2.22(1.79 to 2.74)based on 6,4 and 10 individual study estimates.For COPD,the corresponding estimates were 1.44(1.16 to 1.77),0.47(0.02 to 9.88),and 0.86(0.48 to 1.54)based on 4,2 and 2 estimates.For ischaemic heart disease(IHD)the estimates were 1.11(1.04 to 1.19),1.26(1.03 to 1.53)and 1.15(1.08 to 1.23)based on 6,3 and 4 estimates,while for stroke they were 1.02(0.92 to 1.13),1.08(0.85 to 1.38),and 1.11(0.95 to 1.31)based on 5,3 and 4 estimates.For overall circulatory disease they were 1.10(1.05 to 1.16),1.11(0.84 to 1.46),and 1.15(1.06 to 1.26)based on 3,3 and 4 estimates.CONCLUSION Exclusive cigar smoking is associated with an increased risk of lung cancer,and less so with COPD and IHD.The increases are lower than for cigarettes.
