FDA Study: Cancer risks nearly nil for 1-2 cigars per day
- Cigar smoking can cause cancers of the mouth and throat, even if you do not inhale.
- Cigar smoking can cause lung cancer and heart disease.
- Cigars are not a safe alternative to cigarettes.
However, an FDA staff report shows that smoking up to two cigars a day is associated with minimal significant health risks.
Last year, FDA staff, led by Cindy Chang, published in BMC Public Health a systematic review of the risks of cigar smoking, declaring that their action was “not a formal dissemination of information by the FDA and does not represent agency position or policy.”
The authors reviewed 22 prospective epidemiologic studies on cigars and health outcomes; they produced tables of results for many smoking-related diseases.
This entry will explore results for deaths from all causes and from cancers among men who are primary cigar smokers (no history of cigarette or pipe smoking). Because the 22 studies employed different methods, and because they controlled or adjusted for various factors, the FDA authors did not provide overall summary risk estimates.
First, let’s look at mortality for all causes of death among cigar smokers, compared with never smokers. A relative risk, or RR, of 1 is no risk, and an RR confidence interval that includes 1 is not statistically significant.)
|Table 1. Relative Risk Estimates For All-Cause Mortality Among Men Who Smoke Cigars|
|Publication, Year||Relative Risk (95% Confidence Interval, CI)|
|Best, 1966||1.06 (0.92 – 1.22)|
|Kahn, 1966||1.10 (1.05 – 1.16)|
|Cole, 1974||1.15 (0.70 – 1.90)|
|Carstensen, 1987||1.39 (1.16 – 1.65)|
|Lange, 1992||1.60 (1.30 – 2.00)|
|Ben-Schlomo, 1994||0.48 (0.25 – 0.93)|
|Shanks, 1998||1.08 (1.05 – 1.12)|
Table 1 shows that cigar smokers have an elevated risk for death from all causes. With the exception of the Ben-Schlomo study, all of the estimates are elevated, and four are statistically significant. So it appears that there is a modest increase in risk among cigar smokers for all causes of death.
Next, let’s look at the risks for individual cancers.
|Table 2. Relative Risks For Cancer Mortality Among Men Who Smoke Cigars|
|Cancer Site||Relative Risk Range||No. of Studies / No. of Significant Elevated Estimates|
|Mouth/throat||4.0 – 7.9||3 / 3|
|Esophagus||1.8 – 6.5||4 / 2|
|Stomach||1.2 – 2.3||2 / 1|
|Liver||3.1 – 7.2||2 / 2|
|Pancreas||1.0 – 1.6||4 / 1|
|Larynx||10.0 – 10.3||3 / 3|
|Lung||1.6 – 7.6||6 / 5|
|Bladder||0.9 – 1.9||4 / 0|
It appears that, like cigarette smokers, cigar smokers have elevated cancer risks, especially at places in contact with smoke, such as the mouth/throat, esophagus, larynx and lung. For other sites, like the stomach, pancreas and bladder, elevated risks are minimal and/or based on very limited data.
In other research published by the FDA, primary cigar smokers consumed on average about one and a half cigars per day when they smoked. This is relevant to a key epidemiology principle: the level of risk is related to the level of exposure. Several studies in the Chang review reported results for smoking one or two cigars per day. Here are those results:
|Table 3. Relative Risks (95% CI) for Mortality Among Men Smoking 1 or 2 Cigars Per Day|
|Shanks, 1998||Shapiro, 2000||Other Studies|
|All Causes||1.02 (0.97 – 1.07)||1.04 (0.98 – 1.11)1|
|Mouth/throat||2.12 (0.43 – 6.18)||0 (0.00 – 0.00)|
|Esophagus||2.28 (0.74 – 5.33)||1.80 (0.60 – 5.00)|
|Stomach||1.68 (0.95 – 2.97) 2|
|Pancreas||1.18 (0.69 – 1.89)||0.60 (0.30 – 1.40)|
|Larynx||6.45 (0.72 – 23.3)||6.00 (0.70 – 53.5)|
|Lung||0.90 (0.54 – 1.66)||1.30 (0.70 – 2.40)||1.14 (0.59 – 2.00)1|
|Bladder||0.78 (0.29 – 1.71)||0 (0.00 – 0.00)|
1Kahn 1966, 5 cigars per day or fewer.
2Chao 2002, 5 cigars per day or fewer.
While some risk estimates are elevated, none are statistically significant. The highest risks are for larynx cancer, but they are based on only two deaths in Shanks and one death in Shapiro.
What are the important take-home messages for cigar smokers with respect to risks for all causes of death and for smoking-related cancers? FDA staff concluded that:
[C]igar smoking carries many of the same health risks as cigarette smoking. Mortality risks from cigar smoking vary by level of exposure as measured by cigars per day and inhalation level [not discussed here] and can be as high as or exceed those of cigarette smoking.
However, the data indicates that consumption of up to two cigars per day, while not completely safe, is neither associated with significantly increased risks for death from all causes, nor smoking-related cancers.
In a subsequent post, I will present results for other diseases, including lung and cardiovascular disorders.