Wednesday, November 3, 2010

Mayo Clinic Misinformation About Smokeless Tobacco

For many years, tobacco “experts” at the Mayo Clinic have tarnished the institution’s name by fabricating misinformation about smokeless tobacco. In a 2004 article about such tactics (available here), I noted that the Mayo website contained this irresponsible, unprofessional and demonstrably false statement: “…smokeless tobacco, also called spit tobacco, has health risks just as severe or even more severe as those associated with cigarette smoking.”

Last week, Jennifer A. Kern, a Mayo Clinic behavioral counselor and former smoker, published a quit-smoking blog entry for the official Mayo Clinic web site, in which she invented new health risks related to smokeless tobacco use (here).

Ms. Kern begins with an explicit acknowledgment that smokeless tobacco is an effective substitute for cigarettes: “Those of us who live in the north are moving into the cooler seasons…it's not uncommon to see people switching tobacco products in order to stay indoors while still getting their nicotine fix. Some folks put down cigarettes and pick up smokeless tobacco products such as chewing tobacco and snuff instead.”

Ms. Kern doesn’t like smokers switching to vastly safer smokeless products, so she tries to convince them not to do so by invoking a “just-as-harmful” theme: “Smokeless tobacco products carry carcinogens, or cancer-causing chemicals, just like cigarettes do.”

Next, Ms. Kern turns to outright fabrication: “In fact, a variety of cancers that can be caused by smokeless tobacco use include: mouth and gum, larynx (voice box), esophagus, and salivary gland, as well as non-oral cancers like pancreas, kidney and penile cancer.”

My readers know that a comprehensive meta-analysis published in 2009 found that smokeless tobacco use is not associated with cancers of the mouth and gum, larynx, esophagus, pancreas or kidney (for a full discussion, click here). But what about salivary gland and penile cancer?

For salivary gland cancer, Ms. Kern may have misread a story involving Tony Gwynn, a former major league baseball player. In early October, Gwynn was diagnosed with cancer of the parotid salivary gland (described here), and he commented that “I haven't discussed that with the doctors yet, but I'm thinking it's related to dipping.” Apparently Gwynn and Ms. Kern are unaware that no epidemiologic studies have linked smokeless tobacco use and salivary gland cancer.

Ms. Kern’s most bizarre claim is that smokeless tobacco use causes penile cancer. According to the National Cancer Institute, penile cancer is extremely rare, occurring in only 1,250 American men each year (here). Penile cancer is strongly related to human papillomavirus infections and lack of circumcision (here). Maybe Ms. Kern was referring to a 1995 report linking penile cancer and smokeless use in India (here), but Swedish and American products have not been implicated in numerous epidemiologic studies.

Someone should counsel Ms. Kern and her employer about the public health imperative of sticking to the facts.

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