Cancer-causing Agent Identified in Smokeless Tobacco

Oral carcinogen shown to induce cancer for snuff/chew users

April 2, 2012 -- A chemical present in smokeless tobacco products is a strong oral carcinogen, according to research being presented this week at the American Association for Cancer Research's annual meeting in Chicago.

Although smokeless tobacco products have long been linked with certain cancers, including those of the oral cavity and esophagus, this is the first study to identify a specific chemical present in smokeless tobacco products that induces oral cancer in animals, according to Silvia Balbo, PhD, research associate at the Masonic Cancer Center of the University of Minnesota.

"(S)-N'-nitrosonornicotine, or (S)-NNN, is the only chemical in smokeless tobacco known to cause oral cancer," Balbo said in a press release.

Balbo and colleagues administered (S)-NNN and (R)-NNN to four groups of 24 rats. The rats were given either (S)-NNN alone, (R)-NNN alone, a combination of both, or tap water. The total dose was approximately equivalent to the amount of (S)-NNN to which a smokeless tobacco user would be exposed from chronic use of these products.

All rats assigned to (S)-NNN alone or the combination of the two began losing weight after one year of exposure and died by 17 months. Rats assigned to (R)-NNN or tap water were terminated at 20 months.

All rats assigned to (S)-NNN had esophageal tumors and demonstrated 100% incidence of oral tumors, including tumors of the tongue, buccal mucosa, soft palate, and pharynx. In contrast, researchers found oral tumors in only five of 24 rats given (R)-NNN and esophageal tumors in only three of 24 rats assigned to (R)-NNN.

Twelve rats given the combination of (S)-NNN and (R)-NNN had 153 esophageal tumors and 96 oral tumors.

Since the U.S. Food and Drug Administration regulates tobacco products, Balbo hopes the results of this study will inform regulatory decisions. Moving forward, she and her colleagues hope to identify other chemicals that may be carcinogens in smokeless tobacco and to understand what level of these chemicals is present in smokeless tobacco products.

Dental Visits Critical for Smokers

CDC report: More smokers avoid the dentist

Adult tobacco smokers are four times more likely to develop oral health problems but much less likely than nonsmokers to go to the dentist regularly, according to a report released February 7 by the U.S. Centers for Disease Control and Prevention (CDC).

The study, which included more than 16,000 adults between the ages of 18 and 64 who participated in the 2008 National Health Interview Survey, also found that although more than a third of smokers included in the report said they have three or more dental problems, 20% said they had not been to a dentist in at least five years. Among nonsmokers and former smokers, 10% had stayed away that long.

Cost was cited as the main reason that most adults with an oral health problem did not see a dentist in the past six months; 56% of current smokers, 36% of former smokers, and 35% of never smokers said they could not afford treatment or did not have insurance.

"Overall, current smokers had a poorer oral health status and more oral health problems than either former smokers or never smokers," the report authors noted. "However, current smokers were more likely to think that their oral health problem was important."

The evidence for an association between tobacco use and oral diseases has been clearly shown in every U.S. surgeon general's report on tobacco since 1964. Tobacco use is a risk factor for oral cancers, periodontal diseases, and dental caries, among other diseases.

reported by DrBicuspid.com, Feb 2012.

Dr. Notes:

Because cost is cited as a major factor for smokers and their reluctance to visit the dentist for regular check-ups, I thought I would present some facts.

The average cost for a pack of cigarettes in the state of Minnesota is $6.53.  That’s 33¢ per cigarette.  According to the American Lung Association, the average smoker inhales 3/4 pack, or 15 cigarettes, per day.  After doing the math you'd find that the annual cost for a smoker’s habit totals $1787 plus change.

Now consider this.  The average annual cost of routine dental care (includes 3 cleanings, exams and routine radiographs) would be around $275.  Again, if you crunch the numbers you would find that if the average smoker were to reduce cigarette consumption by 3 cigarettes per day, they could easily afford the out-of-pocket expense of routine dental care.  And these numbers don’t consider the inclusion of dental insurance, which 80% of smokers have, yet don’t utilize.

Our job as a dental office is to address and treat oral health.  We don't give lectures and we don't judge people based on their choices in life, especially their decision to smoke.  But we will provide guidance and advice for those who do.  Regular dental care is crucial for smokers if they wish to minimize the long term effects of their smoking habit.  Routine cleanings and exams can do a lot to help prevent a wide range of problems that smokers are predisposed to and help proactively identify the development of long-term complications that can result from oral tobacco use.