Wednesday, May 24, 2017

A Smokeless Tobacco-Pancreatic Cancer Claim is Refuted

Snus use is not associated with pancreatic cancer, according to a study published in the International Journal of Cancer (abstract here).  Researchers combined data from nine cohort studies that involved 400,000 men in Sweden.  Compared with never users, the risk for current snus users, after adjustment for smoking, was 0.96 (95% confidence interval = 0.83 – 1.11).

The new work was conducted by the Swedish Collaboration on Health Effects of Snus Use, which includes researchers from several Swedish universities.  (In the past, snus research was largely performed by the Karolinska Institute, whose flawed studies I have previously documented here, here, here, and here.)  Their results are almost identical to those in a large study of smokeless use in North America and Europe published six years ago (discussed here), and to findings in another analysis published eight years ago (here).

Focus on a purported smokeless tobacco-pancreatic cancer link began after publication of a cherry-picked meta-analysis by Paolo Boffetta in 2008 (discussed here).  Dr. Boffetta contradicted his own finding in a later study (here), and epidemiologist Peter Lee refuted it in his comprehensive analysis in 2009 (here).  The fact is that there is no credible evidence that American or Swedish smokeless tobacco is linked to pancreatic cancer.      

Remarkably, the National Cancer Institute persists in asserting a pancreatic cancer link in its smokeless tobacco “fact sheet” (here).  That document also asks what should be a rhetorical question: “Is using smokeless tobacco less hazardous than smoking cigarettes?” 

The NCI’s answer is grossly misleading: “all tobacco products are harmful and cause cancer…There is no safe level of tobacco use.”  The agency’s source for this obfuscation is a 31-year-old Surgeon General report that has been eclipsed by three decades of epidemiologic studies.  

It should be noted that the U.S. Food & Drug Administration is equally culpable. That agency used the bogus smokeless-pancreatic cancer link as a talking point in last year’s $36 million campaign against smokeless tobacco (here).

We already knew that moist snuff and chewing tobacco have no measurable risk for mouth cancer (here).  Now there is scientific evidence that smokeless isn’t linked to pancreatic cancer.   


Unknown said...

“all tobacco products are harmful and cause cancer…There is no safe level of tobacco use.” These are not scientific conclusions, but ideological statements. Yes, there is no 'absolutely zero risk' for any substance, so to say "no safe level" meaning absolutely zero risk is a truism, but it is completely meaningless without its proper context.

Bill Godshall said...

Thanks for this comprehensive analysis.
If asked to do so, Trump Administration officials at DHHS appear may end DHHS' three decade long anti-THR propaganda campaign that has deceived Americans about the scientific evidence.