Marc J. Schneiderman, M.D.
The National Cancer Institute's (NCI) Monograph: Cigars, Health Effects and Trends was published in February, 1998. This 232 page compilation of research on the health effects of cigars is important reading for cigar smokers although many conclusions are made that are often unsubstantiated by the research presented. Selective research supporting their viewpoints are offered whereas debate on controversial statements is rarely presented. The message the NCI wants to get out is quoted from the study below:
"Cigar smoking can cause oral, esophageal, laryngeal, and lung cancers. Regular cigar smokers who inhale, particularly those who smoke several cigars per day, have an increased risk of coronary heart disease and chronic obstructive pulmonary disease.
Regular cigar smokers have risks of oral and esophageal cancers similar to those of cigarette smokers, but they have lower risks of lung and laryngeal cancer, coronary artery disease, and chronic obstructive pulmonary disease.
We believe an accurate statement is that the risks of tobacco smoke exposure are similar for all sources of tobacco smoke, and the magnitude of the risks experienced by cigar smokers is proportionate to the nature and intensity of their exposure."
This paper attempts to summarize some of the vital topics of interest to cigar smokers from the NCI study. Many conclusions from the study can be contested and alternatives to some of these addressed.
Overview of Cigar/Disease Risks
The great majority of cigar smokers smoke fewer than one cigar per day and don't inhale. The "habitual" cigar smoker is rarely even a daily smoker. Disease risk ratios comparing cigar smokers to the general non-smoking population are reported by NCI:
|Cause of Death||Nonsmoker||1-2 cigars||3-4 cigars||5+cigars|
|coronary artery disease||1||0.98||1.06||1.14|
This chart demonstrates that the 1-2 cigar/day user who doesn't inhale is not at serious risk for developing cancer or heart disease. The "all cause" of death risk for smokers of 1-2 cigars per day (and sometimes more) is not significantly different when compared to those who never smoked.
Oral cancer studies overwhelmingly suggest that the combination of cigars along with heavy alcohol use dramatically increases these cancers. Alcohol, however, was not addressed as a risk factor in the NCI report. Pancreatic cancers also are associated with alcohol. A recent study was presented demonstrating the relationship between cigar use and pancreas cancer (Muscat, J.E. et al., Smoking and Pancreatic Cancer in Men and Women, Cancer Epidemiology, Biomarkers, and Prevention, 6:15-19, 1997.) One major flaw of the study is that although patients were asked about alcohol consumption, the authors did not report its affect on the pancreatic cancer results. Alcohol is a known carcinogen of the oral, pharyngeal, and GI tract (including stomach, liver, and pancreas.) Why didn't the authors comment on alcohol's impact on this group of patients with pancreatic cancer?
The NCI reports the risk ratio of cigar smokers who develop pancreatic cancer compared to the non-smoking population as 1.18 (1-2 cigars/day.) This risk ratio is not terribly significant yet they conclude, "Cigar smokers have higher rates of pancreatic cancer than nonsmokers, particularly those who smoke higher number of cigars per day. Regression analysis confirms significant relationships with the factors of age, inhalation and cigars per day for primary cigar smokers. These data suggest that cigar smoking is a cause of pancreatic cancer."
They continue: "The relationship of cigar smoking and alcohol consumption, particularly for oral cancers, has not been evaluated; but the established interaction between cigarette smoking and alcohol consumption for oral cancers and the frequent association of cigar smoking with alcohol consumption raise the question of an increased risk from the combination fo (sic) these two behaviors." Although they concede a link between some cancers, tobacco and alcohol consumption, by suggesting the relationship has "not be evaluated", it weakens the argument. The studies they fail to highlight that suggest a significant positive risk between oral cancers and alcohol and tobacco are: Wynder, 1977; Sorall, 1995; and Franceschi, 1992.
A causal relationship between lung cancer and primary cigar smoking has been demonstrated in numerous studies (Wynder, 1972; Gsell, 1972; Wynder, 1977; Joly, 1983; Lublin, 1982; and Higgins, 1988.) To a large degree this relationship is influenced by inhalation practices and quantity of cigars smoked. The NCI reports that at 1-2 cigars per day, there is a lower overall risk of developing lung cancer compared to the non-smoking population (0.99 relative risk.) Since the overwhelming majority of cigar smokers smoke fewer than 1 cigar a day and don't inhale, the majority of cigar smokers appear to be protected from developing lung cancer.
The same conclusion might be true for the risk of developing coronary artery disease in primary cigar smokers. According to the NCI, for primary cigar smokers smoking 1-2 cigars per day the incidence of coronary artery disease is lower than the non-smoking population (0.98 relative risk.) Even at 5+ cigars per day the risk of coronary artery disease in this group compared to the non-smoking population is only .14.
The incidence of emphysema in smokers of 1-2 cigars per day is higher than the non-smoking population according to the NCI report (1.39 relative risk.) Yet surprisingly if you smoke 5+ cigars per day the relative risk of developing emphysema plummets to 1.03. From these data a direct relationship between cigar smoking and emphysema cannot be drawn. However the NCI report concludes, "A more accurate statement would be that the risks experienced by cigar smokers are proportionate to their exposure to tobacco smoke."
Laryngeal cancer has been associated with cigar smoking. As with the relationship of cigar smoking to oral cancers, however, the best study to date is from Wynder, 1977 who links it with alcohol consumption. Quoting from Wynder, "Alcohol was included in this study as an additional risk factor ... the risk for each type of cancer increases with the quantity of liquor consumed, and larger proportions of heavy drinkers (and lower proportions of nondrinkers) occur for cancers of the mouth, larynx, and esophagus than do for lung or bladder cancer... Cancer of the larynx and upper alimentary tract is affected by heavy alcohol intake, as was clearly shown once more by the present study. Alcohol, whose effects interact with cigarette smoke, may be regarded as a promoter of tobacco carcinogenesis... Reduction of excessive alcohol consumption will have an important impact on reducing these types of cancers." Franceschi (1992) concurs, "Although an association could be made between cigars and oral cancer, that association based upon these numbers is not a strong one. The concurrent use of alcohol in these cancers continues to be a significant risk factor."
Their overall conclusion from the NCI about the relationship between cigar smoking and cancer, heart disease, and lung disease is as follows:
"Cigar smoking can cause oral, esophageal, laryngeal and lung cancers. Regular cigar smokers who inhale, particularly those who smoke several cigars per day, have an increased risk of coronary heart disease and chronic obstructive pulmonary disease."
My conclusions based on the NCI reported numbers and a review of the literature follow:
Cigar smoking can cause oral, esophageal, laryngeal, and lung cancers. Still the relationship between cigar smoking and these cancers must be looked at along with other risk factors such as inhalation practices, types of cigars used, alcohol consumption, family history, and other environmental carcinogens. Studies to date do not imply a relationship between cigars and cancers of the prostate, colon, pancreas, kidneys, bone, eye, or brain.
The relationship between the development of coronary artery disease and cigar smoking has been studied. But for the non-inhaling cigar smoker who has never smoked cigarettes, and smokes 1-2 cigars per day, there is no clear cut relationship. These smokers may have lower incidences of coronary artery disease than the non-smoking population. Other factors such as cigarette tobacco exposure, family history, serum cholesterol levels, hypertension, diabetes, and previous coronary events must be factored into the general risk equation. The risk of developing emphysema has been studied in primary cigar smokers. There is a slight risk of developing this disease in the 1-2 cigar a day smoker (1.39 relative risk) As cigar consumption increases past 5 a day, however, this relative risk diminishes to approximately the same as the non-smoking population (1.03.) These data suggest more studies are needed to investigate the relationship between emphysema and cigar smoking. Other risk factors etiological in the development of emphysema such as exposure to cigarette tobacco smoke, family history, other lung diseases and environmental contributors must be addressed in anyone considering cigar smoking.
Nicotine Dependence and Cigars
The NCI reports that cigar smoke contains many carcinogens as well as significant amounts of nicotine. "During curing and fermentation of air-cured tobacco, nitrate is partially reduced to nitrite, most likely by microbal (sic) action. This contributes to the N-nitrosation of nicotine, converting it into the highly carcinogenic, tobacco-specific N-nitrosamines (TSNA), N-nitrosonornicotine (NNN) and 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK) (Burton et al., 1992; Hoffmann et al., 1994; Wiernik et al., 1995)... Rickert et al. (1985) examined the delivery of 'tar', nicotine and CO per liter of smoke for different tobacco products. They found that the mean yields per liter of smoke were highest for small cigars followed by hand-rolled and manufactured cigarettes and were lowest for large cigars. Total delivery was greatest for large cigars because of their larger amount of tobacco ... Carbon monoxide and nicotine are major contributors to the acute toxicity of cigar smoke. Among agents which also add to the acute toxicity of cigar smoke are nitrogen oxides, hydrogen cyanide, ammonia, and volatile aldehydes."
Do cigar smokers absorb nicotine and carbon monoxide? Clearly these agents factor into the development of coronary artery disease. The NCI data demonstrates that primary cigar smokers do not develop coronary artery disease more frequently compared to the non smoking population if they smoke 1-2 cigars per day. This suggests that either cigar nicotine is not easily absorbed through the oral mucosa (carbon monoxide is only absorbed through the lung) or the amount of second hand smoke that non-inhalers are exposed to is minimal.
The conclusions of the NCI are that:
Cigar smoke contains the same toxic and carcinogenic compounds identified in cigarette smoke.
The amount of nicotine available as free, unprotonated nicotine is generally higher in cigars than in cigarettes due to the higher pH of cigar smoke. This free nicotine is readily absorbed across the oral mucosa, and may explain why cigar smokers are less likely to inhale than cigarette smokers.
The NCI reports that two studies are conclusive that nicotine is absorbed orally and cigar smokers get a nicotine "hit" without inhaling. One study from 1970 (Armitage and D.M. Turner, Absorption of Nicotine in Cigarette and Cigars Smoke through the Oral Mucosa, Nature, 226:1231-1232) studied cats blood pressure and ear twitching response to smoke (cigar and cigarette) installed into their mouths while anesthetized. Cigar smoke elevated their blood pressure but cigarette smoke did not. No controls were used. The conclusion of this "study" was that, "The present evidence indicates that cigarette smokers who do not inhale may not obtain a 'stimulant' dose of nicotine from relatively acidic smoke. It may, however, be possible for a cigars smoker to obtain such a dose without inhaling."
There were obvious flaws in this study:
- no correlation of blood levels of nicotine with a physiologic response
- lack of controls
- the effect of inhaling a more irritating alkaline smoke (cigars) to the more acidic, but less irritating smoke (cigarettes). Basing
conclusions on better studies comparing serum nicotine and
carboxyhemoglobin (reflective of carbon monoxide exposure) levels of
cigarette smokers and cigar smokers would have been more appropriate.
Armitage et al. attempted this study, (Armitage, et al., Absorption of
nicotine from small cigars. Clinical Pharmacology and Therapeutics,
23(2): 143-151.) The NCI concludes from this study that cigar smokers
absorb nicotine. 7 male current habitual cigarette smokers who were told not to smoke after midnight the night before the experiment began were used for this study. The volunteers then smoked small cigars and arterial blood was evaluated at 10 minute intervals for nicotine and carbon monoxide levels. They were categorized as either "inhaler" or "slight inhaler/nonsmoker". Cigars and cigarettes were compared. The authors conclude that "Buccal absorption of nicotine is slower and less complete than absorption by the alveolar capillaries... We conclude that cigar smokers can achieve plasma nicotine concentrations as high as those in cigarette smokers by a variable combination of inhalation into the alveoli and mucosal absorption. As the rate of rise of plasma nicotine is slower in cigar smokers, the short-term pharmacologic effects are likely to be less than those in cigarette smokers since the principal pharmacologic effects of nicotine relate not so much to the blood concentration achieved but to the rate of change in that concentration. This probably explains why the heart rate changes observed during cigar smoking were less than after cigarette smoking."
The obvious flaw of this study is in using cigarette starved "current and habitual" cigarette smokers to smoke small cigars. There is no question that these volunteers would inhale a good deal of smoke. Numerous studies demonstrate that ex-cigarette smokers who smoke cigars inhale them (even though they report they don't.) It would have been more appropriate to compare the nicotine levels of current "habitual" primary cigar smokers (who never smoked cigarettes) to cigarette smokers.
There is a study that did just that. (Turner, et al., Effect of cigar
smoking on carboxyhaemoglobin and plasma nicotine concentrations in
primary pipe and cigar smokers and ex-cigarette smokers. British Medical Journal 2: 1387-1389, 1977.) Surprisingly primary cigar smokers DID NOT develop the same serum nicotine or carboxyhemoglobin levels as cigarette smokers. Blood levels of nicotine and carboxyhemoglobin in primary cigar smokers were comparable to those who were exposed only to second hand smoke. However, ex-cigarette smokers who were smoking cigars did develop the nicotine and carboxyhemoglobin levels of current cigarette smokers.
Recall that carbon monoxide is only absorbed through the lungs. Also,
serum carboxyhemoglobin levels accurately reflect exposure to carbon
monoxide. Given the elevated serum carboxyhemoglobin levels demonstrated in ex-cigarette smokers who smoke cigars, it is clear that ex-cigarette smokers, even though they report no inhalation, do inhale.
The authors conclude, "Since ex-cigarette smokers do not seem to lose
their habit of inhaling when they change to cigars, measures aimed at
persuading smokers to switch to cigars will have little effect on their health. Pipe and cigar smokers who have never smoked cigarettes do not inhale, which probably accounts for their reduced incidence of coronary heart disease and lung cancer. But they also appear not to absorb nicotine, which suggests that nicotine is absorbed largely from the lung and that the buccal mucosa is unimportant. It also raises the interesting question of why primary pipe and cigars smokers do smoke." The authors could easily answer that last "interesting question" by lighting up a fine Havana.
The NCI study further concludes "There is sufficient nicotine absorption among regular heavy cigar smokers to expect that nicotine dependence might develop, but studies to document the frequency or intensity of nicotine dependence have not been published."
It's not a mistake to state that for the great majority of primary cigar smokers, addiction to cigars is not an issue. Most cigar smokers smoke fewer than one a day and habitual cigar smokers do not appear to increase their consumption over time. By the way, ever see a group of cigar smokers standing outside a smoke-free office building in the middle of winter to get a cigar "hit"? Unlike cigarette studies, there are no reports demonstrating that teenage cigar users continue smoking cigars into adulthood. Teenage cigarette addiction however is well documented. NCI admits that, "The extensive studies of time course and symptomology of withdrawal symptoms that have been conducted in cigarette smokers have not been duplicated in cigar smokers." Still they go on to conclude, "several lines of evidence suggests that it may be possible cigar smokers to develop a similar syndrome of withdrawal."
The NCI concludes that since nicotine is addicting, absorbed through the oral mucosa, is present in cigars, and studies (Armitage) demonstrate nicotine absorption via cigar smoking, then obviously nicotine addiction would follow, along with typical withdrawal symptoms. It is also clear that cigar smokers are not addicted in the same way as cigarette smokers. NCI tries to explain this, "Lower rates of inhalation in cigar smokers and slower absorption of nicotine through the buccal mucosa suggest that cigar smoking may have a lower potential to induce addiction to nicotine than cigarette smoking. In addition, it is plausible that persons who never had been nicotine dependent and who began smoking cigars in adulthood would be at a lower risk for developing dependence than children and adolescents who take up tobacco use. It does appear that a much higher proportion of adult cigar users compared to adult cigarette smokers are non-daily users."
Nicotine is more addicting in children than adults? This type of
statement which cannot be substantiated, and doesn't even sound
plausible, is present throughout the NCI monograph. Another example can be found in the discussion about why cigar smokers don't inhale. "While almost all cigarette smokers inhale, the majority of cigar smokers do not. This may be due to differences in the pH of the smoke produced by these two products. Cigar smoke contains a substantial fraction of its nicotine as free nicotine, which can be readily absorbed across the oral mucosa. In contrast, cigarette smoke is more acidic, and the protonated form of nicotine it contains is much less readily absorbed by the oral mucosa. As a result, cigarette smokers must inhale to get their required quantity of nicotine, whereas cigar smokers can ingest sufficient quantities of nicotine without inhaling." Turner effectively demonstrated that primary cigar smokers do not develop serum levels of nicotine above those exposed
only to second hand smoke. And, if ex-cigarette smokers who currently
smoke cigars could get their "required quantity of nicotine" via the oral route, why then do they need to inhale?
Some Final Thoughts
In summary the NCI report sheds little new light on the issues of the
health effects of cigars. It is at best an excellent compilation of the research to date. The report reminds us that today adolescents in
increasing numbers are experimenting with cigars. Major cigar
publications, organizations, and personalities, have publicly denounced any tobacco use by adolescents. The decision to responsibly use cigars in moderation is a decision to be made by adults. Responsible use dictates limiting the number of cigars smoked and non inhaling.
My recommendation is that ex-cigarette users refrain from taking up cigars as an alternative to cigarettes and heavy alcohol users should stay away from any tobacco product. Finally, all risk factors for cancer, lung and heart disease, i.e., cigarette smoking, family history, serum cholesterol levels, concurrent high risk diseases (diabetes, hypertension, asthma, etc.) and lifestyle (diet, exercise) must be evaluated in each individual undertaking cigar smoking. Cigar smoking is not without risk but I believe the NCI report clearly demonstrates that those risks are acceptable to those who use the product responsibly.
Marc J. Schneiderman, M.D.
Copyright © 1998-2001,
Marc J. Schneiderman, M.D.
All rights reserved.
Reprinted with permission.