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1.  Mortality and type of cigarette smoked. 
Twenty-five years ago, cigarette smokers in the United Kingdom smoked plain cigarettes with an average tar yield of probably about 35 mg. Now smokers predominantly smoke filter cigarettes and average tar yields have been reduced by half. Epidemiological evidence comparing mortality in smokers of differing types of cigarettes is reviewed. Compared with smokers of higher tar plain cigarettes, smokers of lower tar filters cigarettes have a reduced mortality for lung cancer, for cancer of the buccal cavity, pharynx, larynx, oesophagus, and bladder, for chronic bronchitis and emphysema, and for cirrhosis of the liver. They also have a slightly significant. Problems of interpretation and limitations of the available evidence are discussed. No worthwhile evidence is yet available on smokers of "low tar' (0-10 mg) cigarettes and data are sparse on lifetime smokers of filter cigarettes. Continuing research is important to understand the situation fully, but the trends of lower mortality to be associated with lower tar and nicotine levels are promising.
PMCID: PMC1052113  PMID: 7264528
2.  Measuring the accumulated hazards of smoking: global and regional estimates for 2000 
Tobacco Control  2003;12(1):79-85.
Objective: Current prevalence of smoking, even where data are available, is a poor proxy for cumulative hazards of smoking, which depend on several factors including the age at which smoking began, duration of smoking, number of cigarettes smoked per day, degree of inhalation, and cigarette characteristics such as tar and nicotine content or filter type.
Methods: We extended the Peto-Lopez smoking impact ratio method to estimate accumulated hazards of smoking for different regions of the world. Lung cancer mortality data were obtained from the Global Burden of Disease mortality database. The American Cancer Society Cancer Prevention Study, phase II (CPS-II) with follow up for the years 1982 to 1988 was the reference population. For the global application of the method, never-smoker lung cancer mortality rates were chosen based on the estimated use of coal for household energy in each region.
Results: Men in industrialised countries of Europe, North America, and the Western Pacific had the largest accumulated hazards of smoking. Young and middle age males in many regions of the developing world also had large smoking risks. The accumulated hazards of smoking for women were highest in North America followed by Europe.
Conclusions: In the absence of detailed data on smoking prevalence and history, lung cancer mortality provides a robust indicator of the accumulated hazards of smoking. These hazards in developing countries are currently more concentrated among young and middle aged males.
doi:10.1136/tc.12.1.79
PMCID: PMC1759096  PMID: 12612368
3.  Cigarette smoking and male lung cancer in an area of very high incidence. I. Report of a case-control study in the West of Scotland. 
Altogether 656 male lung cancer cases and 1312 age and sex matched controls were interviewed between 1976 and 1981 in a case-control study of cigarette smoking habits and lung cancer in Glasgow and the West of Scotland, an area with the highest recorded incidence in the world. The relative risk of lung cancer increased significantly for smokers whose consumption was below 20 cigarettes per day but did not rise significantly in those who smoked more than 20 cigarettes per day. Other smoking characteristics such as inhalation and tar yields of brands smoked did not explain this finding. Additionally, the relative risks observed at all levels of cigarette consumption were low in comparison with those in the published literature. By constructing an index of cigarette exposure which included the tar yields of brands smoked, an assessment of the risk of lung cancer in relation to tar exposure independent of amount smoked was derived. Only in smokers of less than 15 cigarettes per day was there a statistically significant reduction in risk of lung cancer associated with lower levels of tar yield.
PMCID: PMC1052678  PMID: 3418284
4.  Switching to low tar cigarettes: are the tar league tables relevant? 
Thorax  1984;39(9):657-662.
Representative samples of smokers of regular middle tar and regular low tar cigarettes responded to a questionnaire concerning their smoking habits and participated in a blind product test, returning 24 hour butt collections from the smoking of both middle tar and low tar cigarettes. An estimate of the mouth intake of tar derived from a measurement of filter nicotine confirmed partial compensation by the low tar smokers relative to the middle tar smokers, resulting in 32% lower tar delivery rather than the 46% expected from the standard machine values. Most middle tar smokers (98%) achieved an estimated tar delivery within or below that of the league table middle tar band when smoking middle tar cigarettes, while 70% of low tar smokers had a mouth intake of 10 X 49 mg or below within the low tar band when smoking low tar cigarettes. These results support the current tar league tables as a guide to the smoker in selecting a lower delivery cigarette.
PMCID: PMC459894  PMID: 6474400
5.  Would a medium-nicotine, low-tar cigarette be less hazardous to health? 
Smoking behaviour and exposure to carbon monoxide, nicotine, and tar were studied in 19 middle-tar smokers. All smoked their own brands for three weeks and then switched to either a conventional low-nicotine, low-tar brand (control) or a medium-nicotine, low-tar cigarette for a further three weeks, the order then being reversed. The medium-nicotine, low-tar brand also had a low delivery of carbon monoxide. With the medium-nicotine, low-tar cigarette mouth-level delivery and intake of nicotine was similar to that with the smokers' usual brands, and significantly greater than with the control low-tar cigarette. Intake of carbon monoxide from the medium-nicotine, low-tar cigarette was significantly less than with either own or control brands. With both low-tar brands mouth-level exposure to tar was reduced relative to smokers' usual cigarettes. There was no evidence, however, that the reduction in tar exposure was greater with the medium-nicotine brand than with the control low-tar cigarette. Both low tar brands were "'oversmoked" relative to subjects' usual middle-tar cigarettes. The medium-nicotine, low-tar cigarette was marginally more acceptable than the control brand, and the particular design used in the study resulted in a lower intake of carbon monoxide. In terms of reducing mouth-level exposure to tar, however, the medium-nicotine, low-tar cigarette had no advantage over the control low-tar product. In part this was because of the ratio of tar to nicotine delivery obtained by human smokers was not the same as that obtained by smoking machine.
PMCID: PMC1507690  PMID: 6794825
6.  Relative intakes of tar, nicotine, and carbon monoxide from cigarettes of different yields. 
Thorax  1984;39(5):361-364.
The relative intakes of tar, nicotine, and carbon monoxide were estimated in 2455 cigarette smokers, who freely smoked their usual brands of cigarette. The estimates were derived by using an objective index of inhaling based on the measurement of carboxyhaemoglobin divided by the carbon monoxide yield of the cigarettes smoked, after background and carry over carboxyhaemoglobin effects had been allowed for. Separate analyses were performed according to the yield and type (plain, filter, etc) of cigarette smoked. The analyses based on yield indicated that the extent of inhaling was adjusted sufficiently to achieve similar intakes of nicotine/carbon monoxide regardless of the nicotine/carbon monoxide yield. It was not, however, sufficiently increased to achieve a similar intake of tar as the tar yield of the cigarette decreased. The analyses based on type of cigarette indicated that the extent of inhaling was adjusted to achieve similar intakes of tar and nicotine regardless of the type of cigarette smoked, but that this led to a greater intake of carbon monoxide among filter cigarette smokers than that among smokers of plain cigarettes--more so than would have been expected from their relative carbon monoxide yields. Two conclusions arise from these results. Firstly, any harmful effects of nicotine/carbon monoxide are unlikely to be materially reduced by smoking cigarettes with lower yields of nicotine/carbon monoxide, but the harmful effects of tar are likely to be reduced by smoking cigarettes with lower tar yields. These predictions appear to be borne out by epidemiological observations. Secondly, any harmful effects of carbon monoxide on the cardiovascular system will be greater in smokers of modern filter cigarettes than in smokers of modern plain cigarettes, provided that these two groups of smokers are otherwise similar with respect to risk of cardiovascular disease.
PMCID: PMC459803  PMID: 6740538
7.  Increased risk of respiratory symptoms in young smokers of low tar cigarettes. 
The effect of cigarettes yielding less than 10 mg tar was investigated in a representative sample (n = 4729) of 16 and 18 year old Finns. The rate of response was 80%. Cough and phlegm were significantly increased in young people smoking low tar cigarettes. When more than nine cigarettes were smoked daily respiratory symptoms were 2.4-6.2 times more prevalent among those who smoked low tar cigarettes than among those who never smoked. No differences were found between the smokers of low tar and medium tar cigarettes (yielding tar 10-18 mg). These data disagree with the hypothesis that the new low tar brands of cigarettes are less likely to cause respiratory symptoms than the old medium tar brands.
PMCID: PMC1415681  PMID: 3922533
8.  Relationship between cigarette yields, puffing patterns, and smoke intake: evidence for tar compensation? 
The relationship between cigarette yields (of nicotine, tar, and carbon monoxide), puffing patterns, and smoke intake was studied by determining puffing patterns and measuring blood concentrations of nicotine and carboxy-haemoglobin (COHb) in a sample of 55 smokers smoking their usual brand of cigarette. Regression analyses showed that the total volume of smoke puffed from a cigarette was a more important determinant of peak blood nicotine concentration than the nicotine or tar yield of the cigarette, its length, or the reported number of cigarettes smoked on the test day. There was evidence of compensation for a lower tar yield over and above any compensation for nicotine. When nicotine yield was controlled for, smokers of lower-tar cigarettes not only puffed more smoke from their cigarettes than smokers of higher-tar cigarettes but they also had higher plasma nicotine concentrations, suggesting that they were compensating for the reduced delivery of tar by puffing and inhaling a greater volume of smoke. The results based on the COHb concentrations were consistent with this interpretation. If an adequate intake of tar proves to be one of the main motives for smoking, then developing a cigarette that is acceptable to smokers and also less harmful to their health will be much more difficult.
PMCID: PMC1499443  PMID: 6819031
9.  Smoking behaviours and attitudes among male restaurant workers in Boston's Chinatown: a pilot study 
Tobacco Control  2002;11(Suppl 2):ii34-ii37.
Design: Cross sectional survey in Chinese of a convenience sample of 54 restaurant workers recruited through extensive outreach activities.
Results: All 54 of the workers were male immigrants. 45 (83.3%) reported smoking cigarettes regularly, and the remaining nine were former smokers. 36 of the smokers (80.0%) started smoking before entering the USA. The workers were aware that cigarettes are addictive (98.1%), cause lung cancer (79.6%), and lead to heart disease (64.8%). However, a substantial number reported that smoking was relaxing (75.9%) and enhanced concentration (66.7%). Nearly half believed low tar and low nicotine cigarettes to be safer than standard brands. The vast majority of workers believed that smoking was not socially acceptable for women. Smokers reported they received information on quitting most commonly from friends (60%), newspapers (53.5%), and television (44.4%). The restaurant workers most often saw advertising against smoking in Chinese newspapers (63%).
Conclusion: Despite high rates of smoking, Chinese American restaurant workers were generally aware of the health risks and were interested in quitting. Community based research can set the stage for targeted public health efforts to reduce smoking in immigrant communities.
doi:10.1136/tc.11.suppl_2.ii34
PMCID: PMC1766070  PMID: 12034979
10.  Mortality in relation to tar yield of cigarettes: a prospective study of four cohorts. 
BMJ : British Medical Journal  1995;311(7019):1530-1533.
OBJECTIVE--To investigate relation between tar yield of manufactured cigarettes and mortality from smoking related diseases. DESIGN--Prospective epidemiological study of four cohorts of men studied between 1967 and 1982. SETTING--Combined data from British United Provident Association (BUPA) study (London), Whitehall study (London), Paisley-Renfrew study (Scotland), and United Kingdom heart disease prevention project (England and Wales). SUBJECTS--Of the 56,255 men aged over 35 who were included in the studies, 2742 deaths occurred among 12,400 smokers. Average follow up was 13 years. MAIN OUTCOME MEASURES--Relative mortality from smoking related diseases according to tar yields of cigarettes smoked. RESULTS--Age adjusted mortality from smoking related diseases in smokers of filter cigarettes was 9% lower (95% confidence interval 1% to 17%) than in smokers related diseases consistently decreased with decreasing tar yield. Relative mortality in cigarette smokers for a 15 mg decrease in tar yield per cigarette was 0.75 (0.52 to 1.09) for lung cancer, 0.77 (0.61 to 0.97) for coronary heart disease, 0.86 (0.50 to 1.50) for stroke, 0.78 (0.40 to 1.48) for chronic obstructive lung diseases, 0.78 (0.65 to 0.93) for these smoking related diseases combined, and 0.77 (0.65 to 0.90) for all smoking related diseases. CONCLUSION--About a quarter of deaths from lung cancer, coronary heart disease, and possibly other smoking related diseases would have been avoided by lowering tar yield from 30 mg per cigarette to 15 mg. Reducing cigarette tar yields in Britain has had a modest effect in reducing smoking related mortality.
PMCID: PMC2548184  PMID: 8520394
11.  Carbon monoxide yield of cigarettes and its relation to cardiorespiratory disease. 
Estimates of the carbon monoxide yield of their cigarettes have been obtained for 4910 smokers (68% of all smokers) in the Whitehall study of men aged 40 to 64. In the 10 years after examination 635 men died. When men smoking cigarettes with high carbon monoxide yield were compared with those smoking cigarettes with a low yield, and after adjusting for age, employment grade, amount smoked, and tar yield, the risk of death was 32% lower for coronary heart disease, 49% higher for lung cancer, and 10% lower for total mortality; these differences were not statistically significant. Among men who said that they inhaled the risk of fatal coronary heart disease was 51% lower in the high carbon monoxide group (p less than 0.01), while the risk of lung cancer was 75% higher. These results provide no evidence that a smoker can reduce his risk of death by smoking a brand with a low carbon monoxide yield; he might even increase it. The complex interactions between characteristics of the smoker, smoking behaviour, constituents of tobacco smoke, and health are again demonstrated.
PMCID: PMC1549826  PMID: 6416512
12.  The tar reduction study: randomised trial of the effect of cigarette tar yield reduction on compensatory smoking. 
Thorax  1995;50(10):1038-1043.
BACKGROUND--Observational and short term intervention studies have reported that smokers of low tar cigarettes inhale more deeply (that is, compensate) than those who smoke high tar cigarettes. To quantify this effect a long term randomised trial was conducted on the effects of switching to low tar cigarettes. METHODS--The trial was carried out between April 1985 and March 1988 among cigarette smokers in the British Civil Service, measuring blood carboxyhaemoglobin (COHb) levels and serum cotinine levels as markers of tobacco smoke intake. Volunteers first switched to a cigarette brand yielding around 10% less tar than their usual brand to identify smokers able to change brand. The 434 subjects who successfully switched were then randomly allocated to one of three groups: (a) "fast reduction" group which changed to a brand of cigarettes with a tar yield of about half that of their usual brand; (b) "slow reduction" group which reduced to the same level in steps over several months; and (c) a control group which continued smoking cigarettes with a tar yield 10% lower than their usual brand. RESULTS--Over the course of the trial cigarette consumption declined slightly in all three groups. In both the "fast reduction" and the "slow reduction" groups, intake of COHb and cotinine was reduced, though not to the same extent as the yield reduction. Comparison of the results before randomisation with those at the end of the trial showed that a reduction in carbon monoxide yield of 45% was associated with a decrease in carbon monoxide intake of 19% (95% confidence interval 14% to 24%) and that a reduction in nicotine yield of 40% was associated with an 11% (6% to 16%) reduction in nicotine intake, reflecting relative intakes of about 1.5 for both carbon monoxide and nicotine in the "fast reduction" group. Results were similar in the "slow reduction" group with a 42% reduction in carbon monoxide yield, a 16% (11% to 22%) reduction in carbon monoxide intake, a 37% reduction in nicotine yield, and a 6% (0% to 13%) reduction in nicotine intake. Estimates of compensation derived from these results were 65% for carbon monoxide, 79% for nicotine, and 62% for tar. CONCLUSIONS--Compensation, demonstrated when switching from a high tar cigarette to a low tar one, was incomplete. Advising people who have failed to give up smoking to switch to low tar cigarettes will reduce the intake of smoke constituents to a small extent. This would be expected to decrease their risk of smoking-related diseases, although by a smaller amount than would be achieved by giving up smoking altogether.
PMCID: PMC475015  PMID: 7491550
13.  Light cigarette smoking impairs coronary microvascular functions as severely as smoking regular cigarettes 
Heart  2007;93(10):1274-1277.
Background
Smoking is the most prevalent and most preventable risk factor for cardiovascular diseases. Smoking low‐tar, low‐nicotine cigarettes (light cigarettes) would be expected to be less hazardous than smoking regular cigarettes owing to the lower nicotine and tar yield.
Objective
To compare the chronic and acute effects of light cigarette and regular cigarette smoking on coronary flow velocity reserve (CFVR).
Methods
20 regular cigarette smokers (mean (SD) age 24.8 (5.0)), 20 light cigarette smokers (mean age 25.6 (6.4)), and 22 non‐smoker healthy volunteers (mean age 25.1 (4.2)) were included. First, each subject underwent echocardiographic examination, including CFVR measurement, after a 12 hour fasting and smokeless period. Two days later, each subject smoked two of their normal cigarettes in a closed room within 15 minutes. Finally, within 20–30 minutes, each subject underwent an echocardiographic examination, including CFVR measurement.
Results
Mean (SD) CFVR values were similar in light cigarette and regular cigarette smokers and significantly lower than in the controls (2.68 (0.50), 2.65 (0.61), 3.11 (0.53), p = 0.013). Before and after smoking a paired t test showed that smoking two light cigarettes acutely decreased the CFVR from 2.68 (0.50) to 2.05 (0.43) (p = 0.001), and smoking of two regular cigarettes acutely decreased CFVR from 2.65 (0.61) to 2.18 (0.48) (p = 0.001).
Conclusion
Smoking low‐tar, low‐nicotine cigarettes impairs the CFVR as severely as smoking regular cigarettes. CFVR values are similar in light cigarette and regular cigarette smokers and significantly lower than in controls.
doi:10.1136/hrt.2006.100255
PMCID: PMC2000949  PMID: 17502323
light cigarettes; coronary flow reserve; echocardiography
14.  Cigarettes, lung cancer, and coronary heart disease: the effects of inhalation and tar yield. 
Ten-year mortality rates for lung cancer and coronary heart disease have been related to cigarette smoking habits in 17 475 male civil servants aged 40-64 and in sample of 8089 male British residents aged 35-69. Both diseases were more frequent in smokers. Lung cancer rates were higher overall for "non-inhalers", particularly in heavy smokers. Tar yield correlated with the risk of lung cancer in non-inhalers but less so in inhalers. Conversely, coronary deaths were more common among inhalers, and the effect of tar/nicotine yield (such as it was) was confined to inhalers. It appears that there are subtle interactions between the amount smoked, the tar/nicotine yield of the cigarette, and the style of smoking. Thus the effects of a change in cigarette characteristics are hard to predict, and they may be different for respiratory and cardiovascular disease.
PMCID: PMC1052907  PMID: 7119654
15.  Respiratory effects of lowering tar and nicotine levels of cigarettes smoked by young male middle tar smokers. II. Results of a randomised controlled trial. 
STUDY OBJECTIVE--The aim was to investigate the effect on respiratory health of male middle tar smokers changing the tar and nicotine levels of the cigarettes they smoke for a six month period. DESIGN--This was a randomised controlled trial. Middle tar smokers were randomly allocated to smoke one of three different types of cigarette (low tar, middle nicotine; middle tar, middle nicotine; and low tar, low nicotine) in place of their usual cigarette for a six month period. Main outcome measures were assessment of respiratory health by documenting respiratory symptoms and peak expiratory flow rates, and of nicotine inhalation by measuring the urinary excretion of nicotine metabolites. SETTING--21 local authority districts of England. SUBJECTS--Participants were male middle tar smokers aged 18-44 years. MAIN RESULTS--Changes in the measures of respiratory health showed little difference over the trial period between the three cigarette groups. Analyses of the urinary nicotine metabolites showed that smokers allocated to each of the three study cigarettes adjusted their smoking so that throughout the trial their nicotine inhalation differed little from their pretrial intakes when they were smoking their own cigarettes. As a result of the altered patterns of smoking to compensate for the reduced nicotine yields of the three study cigarettes, the tar intake of those allocated to smoke the middle tar, middle nicotine cigarettes remained essentially unchanged, while those allocated to smoke the low tar, low nicotine and low tar, middle nicotine cigarettes had calculated reductions in tar intakes of about 14% and 18%, respectively. CONCLUSIONS--Due to the phenomenon of compensation, tar intake can only be reduced substantially by using a cigarette with a markedly lower tar/nicotine ratio. Nevertheless reductions of up to about 18% in tar intake failed to result in any detectable effect on respiratory symptoms or peak expiratory flow rates over a six month period.
PMCID: PMC1059568  PMID: 1645087
16.  Respiratory effects of lowering tar and nicotine levels of cigarettes smoked by young male middle tar smokers. I. Design of a randomised controlled trial. 
STUDY OBJECTIVE--The aim was to investigate the effect on respiratory health of male middle tar smokers changing the tar and nicotine levels of the cigarettes they smoke for a six month period. DESIGN--This was a randomised controlled trial. Middle tar smokers were randomly allocated to smoke one of three different types of cigarette (low tar, middle nicotine; middle tar, middle nicotine; and low tar, low nicotine) in place of their usual cigarette for a six month period. Main outcome measures were assessment of respiratory health by documenting respiratory symptoms and peak expiratory flow rates, and of nicotine inhalation by measuring the urinary excretion of nicotine metabolites. SETTING--21 local authority districts of England. SUBJECTS--Participants were male middle tar smokers aged 18-44 years. MAIN RESULTS--Postal questionnaires were sent to 265,016 individuals selected from the electoral registers of 21 local authority districts of England; 64% of questionnaires were returned revealing 7736 men aged 18-44 years who smoked only middle tar cigarettes. Of these, 7029 (90%) were sent a health warning and 707 (10%) were not; the latter acted as a control group to assess the effect of the health warning. Of the 7029 men who had received a health warning and were visited at the recruitment stage, 2666 agreed and were eligible to participate in the trial although only 1541 (58% of those who agreed and were eligible) actually started smoking the study cigarettes; 643 men (24% of those willing to participate at the beginning of the trial and 42% of those who actually started smoking the study cigarettes) completed the trial smoking the study cigarettes. Of these, 213 were in the low tar middle nicotine group, 220 were in the middle tar middle nicotine group, and 210 were in the low tar low nicotine group. CONCLUSIONS--This study shows the feasibility of identifying and recruiting sufficient numbers of male middle tar smokers, with adequate numbers completing the trial, to detect any changes in respiratory health over a six month period.
PMCID: PMC1059567  PMID: 1645086
17.  Tobacco‐related disease mortality among men who switched from cigarettes to spit tobacco 
Tobacco Control  2007;16(1):22-28.
Background
Although several epidemiological studies have examined the mortality among users of spit tobacco, none have compared mortality of former cigarette smokers who substitute spit tobacco for cigarette smoking (“switchers”) and smokers who quit using tobacco entirely.
Methods
A cohort of 116 395 men were identified as switchers (n = 4443) or cigarette smokers who quit using tobacco entirely (n = 111 952) when enrolled in the ongoing US American Cancer Society Cancer Prevention Study II. From 1982 to 31 December 2002, 44 374 of these men died. The mortality hazard ratios (HR) of tobacco‐related diseases, including lung cancer, coronary heart disease, stroke and chronic obstructive pulmonary disease, were estimated using Cox proportional hazards regression modelling adjusted for age and other demographic variables, as well as variables associated with smoking history, including number of years smoked, number of cigarettes smoked and age at quitting.
Results
After 20 years of follow‐up, switchers had a higher rate of death from any cause (HR 1.08, 95% confidence interval (CI) 1.01 to 1.15), lung cancer (HR 1.46, 95% CI 1.24 to 1.73), coronary heart disease (HR 1.13, 95% CI 1.00 to 1.29) and stroke (HR 1.24, 95% CI 1.01 to 1.53) than those who quit using tobacco entirely.
Conclusion
The risks of dying from major tobacco‐related diseases were higher among former cigarette smokers who switched to spit tobacco after they stopped smoking than among those who quit using tobacco entirely.
doi:10.1136/tc.2006.018069
PMCID: PMC2598436  PMID: 17297069
18.  Health impact of "reduced yield" cigarettes: a critical assessment of the epidemiological evidence 
Tobacco Control  2001;10(Suppl 1):i4-i11.
Cigarettes with lower machine measured "tar" and nicotine yields have been marketed as "safer" than high tar products over the last four decades, but there is conflicting evidence about the impact of these products on the disease burden caused by smoking. This paper critically examines the epidemiological evidence relevant to the health consequences of "reduced yield" cigarettes. Some epidemiological studies have found attenuated risk of lung cancer but not other diseases, among people who smoke "reduced yield" cigarettes compared to smokers of unfiltered, high yield products. These studies probably overestimate the magnitude of any association with lung cancer by over adjusting for the number of cigarettes smoked per day (one aspect of compensatory smoking), and by not fully considering other differences between smokers of "high yield" and "low yield" cigarettes. Selected cohort studies in the USA and UK show that lung cancer risk continued to increase among older smokers from the 1950s to the 1980s, despite the widespread adoption of lower yield cigarettes. The change to filter tip products did not prevent a progressive increase in lung cancer risk among male smokers who began smoking during and after the second world war compared to the first world war era smokers. National trends in vital statistics data show declining lung cancer death rates in young adults, especially males, in many countries, but the extent to which this is attributable to "reduced yield" cigarettes remains unclear. No studies have adequately assessed whether health claims used to market "reduced yield" cigarettes delay cessation among smokers who might otherwise quit, or increase initiation among non-smokers. There is no convincing evidence that past changes in cigarette design have resulted in an important health benefit to either smokers or the whole population. Tobacco control policies should not allow changes in cigarette design to subvert or distract from interventions proven to reduce the prevalence, intensity, and duration of smoking.


Keywords: tar and nicotine; lung cancer; changing cigarette
doi:10.1136/tc.10.suppl_1.i4
PMCID: PMC1766045  PMID: 11740038
19.  Nicotine fading and self-monitoring for cigarette abstinence or controlled smoking. 
This study compared four treatment approaches to cigarette smoking: (1) a nicotine fading procedure, in which subjects changed their cigarette brands each week to ones containing progressively less nicotine and tar; (2) a self-monitoring procedure in which subjects plotted their daily intake of nicotine and tar; (3) a combined nicotine fading/self-monitoring procedure; and (4) a slightly modified American Cancer Society Stop Smoking Program. Thirty-eight habitual smokers were assigned to one of the treatment groups. The study had two goals: (1) to achieve a clinically significant percentage of abstinence, and (2) to reduce the nonabstainers' smoking to a "safer" level by having them smoke low tar and nicotine cigarettes. The 18-month followup results showed that the nicotine fading/self-monitoring group was the most successful: 40% were abstinent and all who had not quit were smoking cigarettes lower in tar and nicotine than their baseline brands. Half the nonabstainers had decreased their rate of smoking relative to baseline while the other half had increased. Furthermore, the fading/self-monitoring group achieved the largest reductions from baseline in daily nicotine and tar intake (61% and 70% respectively). The results suggest that the study's goals were achieved and that the nonaversive combined procedure could be used to treat not only habitual smokers but also smokers with severe cardiovascular and respiratory problems, because it does not have some of the inherent limitations of the successful aversive smoking cessation procedures.
doi:10.1901/jaba.1979.12-111
PMCID: PMC1311353  PMID: 468744
20.  Inhaling habits among smokers of different types of cigarette. 
Thorax  1980;35(12):925-928.
Inhaling habits were studied in 1316 men who freely smoked their usual brands of cigarette. An index of inhaling was calculated for each person by dividing the estimated increase in carboxyhaemoglobin level from a standard number of cigarettes by the carbon monoxide yield of the cigarette smoked. Smokers of ventilated filter cigarettes inhaled 82% more than smokers of plain cigarettes (p less than 0.001) and those who smoked unventilated filter cigarettes inhaled 36% more (p less than 0.001). Cigarette consumption was similar among smokers of each type of cigarette. Assuming that the intake of tar and nicotine is proportional to the inhaling index, the intake in either group of filter cigarette smokers would have been less than that in plain cigarette smokers. Among smokers of unventilated cigarettes, however, the intake would not have been much less.
PMCID: PMC471416  PMID: 7268668
21.  Educating smokers about their cigarettes and nicotine medications 
Health Education Research  2010;25(4):678-686.
The objective of this study was to test the efficacy of specially designed educational materials to correct misperceptions held by smokers about nicotine, nicotine medications, low tar cigarettes, filters and product ingredients. To accomplish this, 682 New York State Smokers’ Quitline callers were randomized to one of two groups: control group received counseling, nicotine patches and quit smoking guide; and experimental group received counseling, nicotine patches, quit guide, plus information about cigarette characteristics mailed in a brand-tailored box. Participants were contacted 1 month later to assess knowledge about cigarettes and actions taken to alter smoking behavior. The results found that respondents in the experimental condition were more likely to report using and sharing the test materials with others compared with the control condition. Overall mean knowledge scores for the experimental group were slightly higher compared with those who received the standard materials. Knowledge of cigarette ingredients was not related to quit attempts or quitting smoking. This study found that the experimental materials were better recalled and contributed to higher levels of knowledge about specific cigarette design features; however, this did not translate into changes in smoking behavior.
doi:10.1093/her/cyp069
PMCID: PMC2912549  PMID: 20064838
22.  Cellular effects of smoke from "safer" cigarettes. 
British Journal of Cancer  1984;49(3):333-336.
Mutagenicity and cytotoxicity are basic cellular effects of cigarette smoke which underlie the development of lung cancer and chronic obstructive airways disease. This study reports that, on a weight-for-weight basis, cigarette smoke condensates from low, middle and high tar cigarettes produce similar mutagenic effects detected by induced sister chromatid exchanges and similar cytotoxic effects detected by vital dye exclusion in human leucocytes. These findings, taken with the strong evidence that smokers extract more smoke from lower tar cigarettes to compensate for low nicotine yields, suggest that the health dangers associated with smoking these "safer" products are underestimated.
PMCID: PMC1976752  PMID: 6704309
23.  Phlegm production and lung function among cigarette smokers changing tar groups during the 1970s. 
In 1971-3 data on smoking habits, cigarette brand smoked, morning phlegm production, and lung function were recorded for factory workers as part of the Heart Disease Prevention Project. These men were reassessed in 1984 and those who had always smoked cigarettes from the same tar group were compared with those who had dropped one tar group (mean decreases of 6.6 mg tar, 0.1 mg nicotine) and two tar groups (mean decreases of 11.9 mg tar, 0.5 mg nicotine). Over the 13 years, men who had dropped one tar group were significantly more likely (p less than 0.05) to stop producing phlegm, but the effect was less marked for those who had dropped two tar groups. The mean fall in FEV1 was similar in all three groups, but 95% confidence limits showed that although dropping one tar group could be associated with at most a saving of 84 ml over the follow up period, there could be little extra benefit from dropping two tar groups. In 1984, all three groups of smokers excreted similar amounts of nicotine metabolites in the urine, suggesting that men who had dropped two tar groups compensated for the reduced nicotine yield of their cigarettes. This could account for the lack of a dose response relationship between reduction in the tar yield of cigarettes and cessation of phlegm and fall in FEV1.
PMCID: PMC1052503  PMID: 3746171
24.  Validity of smokers' information about present and past cigarette brands--implications for studies of the effects of falling tar yields of cigarettes on health. 
Thorax  1986;41(3):203-207.
Four hundred and twenty nine current smokers and ex-smokers who had provided details 12 years previously completed a self administered questionnaire about their present and past smoking habits, and two weeks later current smokers supplied an empty cigarette packet. The tar group and brand name of the current cigarette given on the questionnaire were compared with details on the packet, and the brand alleged to have been smoked 12 years ago was compared with that actually recorded at that time. Only 55% of "low middle" tar cigarettes as indicated by returned packets had been correctly identified in the questionnaire. The brand name was the same in the questionnaire and on the packet in 74% of cases. The recalled brand was confirmed by past records in only 49% of cases. It is concluded that current smokers should be asked to return an empty packet or packets of the cigarette brand or brands usually smoked with a self administered questionnaire and that follow up studies of populations for which brands of cigarette smoked were previously recorded might be more valid than studies relying on recall.
PMCID: PMC460294  PMID: 3715776
25.  γH2AX: A potential DNA damage response biomarker for assessing toxicological risk of tobacco products 
Mutation research  2009;678(1):10.1016/j.mrgentox.2009.06.009.
Differentiation among American cigarettes relies primarily on the use of proprietary tobacco blends, menthol, tobacco substitutes, paper porosity, paper additives, and filter ventilation. These characteristics substantially alter per cigarette yields of tar and nicotine in standardized protocols promulgated by government agencies. However, due to compensatory alterations in smoking behavior to sustain a preferred nicotine dose (e.g., by increasing puff frequency, inhaling more deeply, smoking more cigarettes per day, or blocking filter ventilation holes), smokers actually inhale similar amounts of tar and nicotine regardless of any cigarette variable, supporting epidemiological evidence that all brands have comparable disease risk. Consequently, itwould be advantageous to develop assays that realistically compare cigarette smoke (CS)-induced genotoxicity regardless of differences in cigarette construction or smoking behavior. One significant indicator of potentially carcinogenicDNA damage is double strand breaks (DSBs), which can be monitored by measuring Ser 139 phosphorylation on histone H2AX. Previouslywe showed that phosphorylation of H2AX (defined as γH2AX) in exposed lung cells is proportional to CS dose. Thus, we proposed that γH2AX may be a viable biomarker for evaluating genotoxic risk of cigarettes in relation to actual nicotine/tar delivery. Here we tested this hypothesis by measuring γH2AX levels in A549 human lung cells exposed to CS from a range of commercial cigarettes using various smoking regimens. Results show that γH2AX induction, a critical event of the mammalian DNA damage response, provides an assessment of CS-induced DNA damage independent of smoking topography or cigarette type. We conclude that γH2AX induction shows promise as a genotoxic bioassay offering specific advantages over the traditional assays for the evaluation of conventional and nonconventional tobacco products.
doi:10.1016/j.mrgentox.2009.06.009
PMCID: PMC3863591  PMID: 19591958
Tobacco smoke; H2AX; Double strand breaks; DNA damage

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