Does Chewing Tobacco Cause Cancer?

Chewing tobacco, often known as “dip” and “snus” has been a worldwide issue for many years now. Part of the reason for this issue is due to its presence with several professional models.  Chewing tobacco is extremely common in the professional sport of baseball and many players are shown up close on live television with their lips packed with dip.  I remember watching Barry Bonds and Sammy Sosa when I was a kid and I would always ask what is in these professional athlete’s lips.  Today, in some stadiums they have banned chewing tobacco not only for players on the field, but for spectators as well, as researchers try and stop the perilous issue.

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I personally have never tried smokeless tobacco, but many of my friends on my baseball and sports teams have dabbled with it.  Each day they have a lip in, I see them becoming more and more addicted, as they continue to use the product exponentially in the following days.  If on one day they are using it once, in proceeding days they will do it twice as much as their addiction grows. The reason for this addiction is due to the fact that smokeless tobacco contains nicotine as the main ingredient, as well as up to 30 other carcinogens, some similar to those found in cigarettes. Many people start using these products at younger ages, due to peer pressure and its availability in the market. In many states, the legal age to purchase tobacco products is 18, however many people start younger than this.

In 11 studies conducted examining the risk of oral cancer, researchers looked into the relative risk of oral cancer by using smokeless tobacco.  The null hypothesis in these studies would be that chewing tobacco has no effect on cancer, and the alternative hypothesis would be that there is a causal link between smokeless tobacco and oral cancer.  In a sample of 948 male participants in 2002, it was found that in only 6% of the cases that oral cancer was present, however, in other countries, the risk was much more prevalent.  For example, in Sudanese men, 68% of the 627 cases examined were attributed to oral cancer.  In other studies conducted from Asia and Africa, consistent evidence for increased risk of oral cancer was present, in which this risk reached a height of 10.  These ecological studies provided a positive correlation between smokeless tobacco use and oral cancer. These studies were large, and well-conducted as the researchers attempted to rule out confounding variables such as alcohol use and other tobacco use.  Ultimately, at a 95% confidence interval, the p-value happened to be quite narrow as it resulted in less than 0.001.  This number is the probability that these results were to occur by chance.

 

imagesAlthough these studies were well-conducted, this does not rule out confounding variables and chance completely, as we have learned that any study can be partially due to chance. However, these results were significant enough to raise a problem and provide a correlation. Other factors that should be looked at are the frequency of exposure to these products as well as family history.  Also, a more efficient way to get better results could be to set up a randomized double-blind control trial, in which participants would be set up into two groups, one being the group that does chewing tobacco, and the other being the group that does not partake. These groups could be followed for a longer duration of time, say 10 years and then results could be taken by doing an examination of the gums.

My advice would be to stay away from these products completely.  I would not recommend switching from cigarettes to chewing tobacco either, even though the chance of getting cancer from smokeless tobacco is much more slim, there are still several risks and these risks should not be taken.

 

Sources:

http://www.mayoclinic.org/healthy-lifestyle/quit-smoking/in-depth/chewing-tobacco/art-20047428?pg=2

http://www.sciencedirect.com/science/article/pii/S1470204508701736

1 thought on “Does Chewing Tobacco Cause Cancer?

  1. Ryan Eric Freeman

    It sounds extremely gross but it can happen. One of my friends from the satellite campus use to chew Tobacco and during a doctors check up he received notice that he had a pebble size cancer tumor in his bottom lip. Likely, it was quickly found and removed but it is a situation that you put yourself in when chewing tobacco. What is ironic is that he was a big baseball player. Do you think there is a correlation between playing baseball and chewing tobacco or is it due only to chance?

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