Wednesday, August 24, 2016

FDA Study: Cancer Risks Nearly Nil for 1-2 Cigars Per Day


The FDA, which now regulates cigars, has taken the position that “cigar smoking carries many of the same health risks as cigarette smoking.”  The agency is requiring cigar packages and ads to display six new warnings, including:
  • 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 (available here) 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, YearRelative Risk (95% Confidence Interval, CI)
Best, 19661.06 (0.92 – 1.22)
Kahn, 19661.10 (1.05 – 1.16)
Cole, 19741.15 (0.70 – 1.90)
Carstensen, 19871.39 (1.16 – 1.65)
Lange, 19921.60 (1.30 – 2.00)
Ben-Schlomo, 19940.48 (0.25 – 0.93)
Shanks, 19981.08 (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 SiteRelative Risk RangeNo. of Studies / No. of Significant Elevated Estimates



Mouth/throat4.0 – 7.93 / 3
Esophagus1.8 – 6.54 / 2
Stomach1.2 – 2.32 / 1
Liver3.1 – 7.22 / 2
Pancreas1.0 – 1.64 / 1
Larynx10.0 – 10.33 / 3
Lung1.6 – 7.66 / 5
Bladder0.9 – 1.94 / 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 (here), primary cigar smokers consumed on average about 1 ½ 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, 1998Shapiro, 2000Other Studies




All Causes1.02 (0.97 – 1.07)
1.04 (0.98 – 1.11)1




Cancer


Mouth/throat2.12 (0.43 – 6.18)0 (0.00 – 0.00)
Esophagus2.28 (0.74 – 5.33)1.80 (0.60 – 5.00)
Stomach

1.68 (0.95 – 2.97) 2
Pancreas1.18 (0.69 – 1.89)0.60 (0.30 – 1.40)
Larynx6.45 (0.72 – 23.3)6.00 (0.70 – 53.5)
Lung0.90 (0.54 – 1.66)1.30 (0.70 – 2.40)1.14 (0.59 – 2.00)1
Bladder0.78 (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 “cigar 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. 


Wednesday, August 17, 2016

Low-Tar Cigarettes Had Merit, Said American Cancer Society; So Do E-Cigarettes



E-cigarette opponents routinely claim that e-cigarettes benefit from industry-promoted consumer health misconceptions in the same manner that so-called light cigarettes soared in popularity years ago, when, it is alleged, marketers created a mythology about the relative safety of “reduced tar.”  In reality, there is more truth in those light claims than people suspect.

According to one heavily cited account (here), “In the late 1960s, tobacco manufacturers introduced ‘light’ or ‘low tar’ brands that yielded 7–14 mg tar per cigarette, compared to the 22 mg tar of the average cigarette sold at that time.   Later, ‘ultralight’ brands appeared, with tar yields below 7 mg per cigarette.  Today [in 2004], almost 90% of cigarettes sold in the United States are in these categories.  Better taste is not the reason why smokers buy light cigarettes.  They buy them because they have the misconception that smoking lower tar products reduces their risk of lung cancer and other tobacco-related diseases.  Advertisements for these brands carry the implicit and tempting message that switching to a light brand is an alternative to quitting smoking.”

This line – that safer cigarettes are a deception perpetrated by the tobacco industry -- has been repeated so often that it is considered gospel by the American public.  In fact, the scientific literature supports the relative safety claim and debunks the popular myth.

Research published in the 1970s documented that low-tar low-nicotine cigarettes were less hazardous than others.  Articles from the American Cancer Society in respected medical journals played a prominent role in shaping consumers’ positive perception of these products. 

In 1976 the Cancer Society published research (here) showing that light cigarettes were safer.  In 1959-60, over a million people were enrolled by the Cancer Society in a prospective epidemiological study of cancer risk factors.  Smokers were classified according to nicotine-tar content, high (2.0-2.7 milligrams nicotine and 26-36 mg tar) or low (less than 1.2 mg nicotine and less than 18 mg tar); detailed records were obtained for death rates and dates. 

The study revealed that the death rate from all causes was 16% lower among smokers of low nicotine-tar cigarettes than among smokers of high nicotine-tar cigarettes.  Similarly, low nicotine-tar smokers had a 14% lower death rate from heart attacks and a 26% lower rate from lung cancer.  The authors concluded that “total death rates, death rates from coronary heart disease, and death rates from lung cancer were somewhat lower for those who smoked ‘low’ tar-nicotine cigarettes than for those who smoked ‘high’ tar-nicotine cigarettes.”

The research findings were extensively reported on by the media (example here).

In 1979, Cancer Society investigators published a study in the New England Journal of Medicine, confirming the 1976 lung cancer findings (abstract here).  This study examined the lungs of 211 men who died in 1955-60 and 234 men who died in 1970-77.  Researchers looked for microscopic changes indicating that a cancerous tumor might have eventually developed if these men had lived longer.



Percentage (%) of Smokers Who Had Pre-Cancerous Lung Changes At Autopsy, According to the American Cancer Society
Smoking CategoryFull-Tar Smokers, 1955-60Light-Tar Smokers, 1970-77
Non-smokers0%0%
Less than 1 pack per day2.60.1
1-2 packs per day13.20.8
2+ packs per day22.52.2


The results from this study are shocking.  In 1955-60, when most smokers consumed full-tar cigarettes, 2.6% of men who smoked less than a pack per day had pre-cancerous changes in their lungs.  Among men smoking 1-2 packs per day, 13% had changes; this increased to 23% among those smoking over 2 packs per day.  But in 1970-77, when, according to the report, “a large proportion of smokers have deliberately selected brands with reduced tar and nicotine,” the percentage of smokers in every category who had pre-cancerous lung changes was very small.

Cancer Society researchers concluded: “The evidence from this study is consistent with evidence from epidemiologic studies indicating that death rates from lung cancer are lower among men who smoke low tar/nicotine cigarettes than among men who smoke the same number of high tar/nicotine cigarettes per day…”

Again, the results were widely reported by the national media, including the Wall Street Journal (here).  Cancer Society president LaSalle D. Leffall, Jr., issued a harm reduction message, saying that “findings of the new study suggest a way for smokers to reduce their lung cancer risk by switching to low tar-nicotine cigarettes if they find it impossible to quit entirely.”  Leffall noted that “the best way to escape the risk of lung cancer ‘is not to smoke at all…There is no safe cigarette.’”

By the 1980s, public health experts and cigarette manufacturers alike were optimistic about the prospects of a safer cigarette.  Manufacturers introduced products with even lower levels of tar, which they called ultra-lights. 

In 2004, Cancer Society researchers confirmed that smoking ultra-lights resulted in lower lung cancer rates than the full-tar cigarettes, but the rates for ultra-lights were the same as those for low-tar cigarettes (here).

The health advantages of light cigarettes over full-flavor brands were documented and promoted by the American Cancer Society in 1976 and 1979.  Optimism about low-tar brands was later reversed by another Cancer Society report, which did not acknowledge or cite the earlier studies. 

One fact is not debatable: The public health community conducted research that led to the promotion of light cigarettes as safer alternatives.  Therefore, there is no industry conspiracy template for anyone to employ against e-cigarettes.



Wednesday, August 10, 2016

A Smokeless History Lesson For Vaping Advocates



E-cigarettes are under siege by federal health authorities and NGOs, aided and abetted by countless university researchers funded generously by the National Institutes of Health (here).  Many of their tactics were introduced 35 years ago.  Here, in brief, is the story of smokeless. 

The American anti-smokeless campaign started on March 26, 1981, when Deborah Winn, Ph.D., reported in the New England Journal of Medicine that the relative risk for oral cancer among powdered dry snuff users was 4, a risk she described as "exceptionally high".  In reality, that risk translated to a mere 12 deaths per year among 100,000 long-term users (For perspective, compare this with the contemporary annual U.S. death rate of 10 per 100,000 users of automobiles, here).  Winn studied only the use of powdered dry snuff, not the moist snuff and chewing tobacco that the vast majority of American smokeless tobacco consumers prefer.  She later acknowledged in two obscure scientific publications – a 1983 IARC report (here) and the 1986 Banbury Report 23 from Cold Spring Harbor Laboratory – that her study involved only dry powdered snuff, but her omission of that critical detail in the initial article set the stage for condemnation of all smokeless products as health hazards (discussed in detail here). 

Winn also falsely inflated the moderate relative risk of 4 to a startling and unsubstantiated 50 (explained in detail here).  The fifty fabrication was adopted by public health agencies and associations worldwide, and continues to pollute the web sites of the American Cancer Society (here) and the State of Kentucky (here), among many others.

The office of the Surgeon General of the United States has been tarnished by the campaign to demonize smokeless products.  Surgeon General Richard Carmona grossly distorted the facts when he testified before Congress in 2003, saying “there is no significant evidence that suggests smokeless tobacco is a safer alternative to cigarettes.”  I also testified at that hearing (here) and published in the Washington Times the following week an op-ed dismantling Dr. Carmona’s testimony (here).  It was another Surgeon General, Antonia Novello, whose 1994 false claim, “The majority of our experts predict an oral cancer epidemic if the current trends in spit tobacco use continue,” (here) prompted me to enter the field of tobacco harm reduction. There was never any basis for that prediction, and it was never realized. 

Major medical institutions have damaged their credibility by spreading misinformation about smokeless tobacco.  These include the Mayo Clinic, the Legacy Foundation, the National Cancer Institute (here) and others.  Other examples of this scientific travesty were described in a comprehensive review of tobacco harm reduction penned by William Godshall and me in 2006 (here).

Today, e-cigarettes are attracting growing support from public health proponents who recognize their value as safer alternatives for cigarette smokers.  It is consternating, however, that some of these experts persist in demonizing smokeless tobacco products whose relative safety is supported by dozens of irrefutable epidemiologic research studies. 


Thursday, August 4, 2016

New Risk Factor for Mouth & Throat Cancer: Hepatitis C Virus



Hepatitis C is a risk factor for mouth and throat cancer, say researchers from the University of Texas MD Anderson Cancer Center (abstract here).

Hep C is a serious viral infection of the liver, mainly transmitted through infected blood via shared needles and accidental needle sticks or through sexual contact (here).  It can cause liver damage and failure, and it is a risk factor for liver cancer.  Hep C kills 19,000 Americans yearly, but there are effective treatments (here).     

The researchers, led by first author Parag Mahale, had access to 34,500 blood samples from MD Anderson cancer patients treated between 2004 and 2014.  The researchers divided Hep C patients into two groups: those who had cancers of the head and neck region (n = 609) and controls with cancers of the lung, esophagus and bladder (n = 1,143).  They looked for differences in Hep C infection rates.

Mahale and colleagues found that about 14% of people with mouth or throat cancer were infected with Hep C, which is about twice the rate as controls (OR = 2.0, 95% confidence interval, CI = 1.04 – 4.01).  The association was somewhat higher in patients who had mouth or throat cancer and who were infected with human papillomavirus, HPV (OR = 3.0, CI = 1.3 – 6.8). 

I have previously discussed the emerging evidence for HPV as a risk factor for mouth and throat cancer (here and here).  The new research suggests that Hep C may also play a causative role.