The cost to taxpayers of the FDA’s new anti-smokeless tobacco campaign, dubbed The Real Cost, is $36 million. FDA Center for Tobacco Products Director Mitch Zeller announced the campaign at the 8th National Summit on Smokeless and Spit Tobacco, which was attended by a “coalition of organizations, agencies and individuals committed to reducing and eventually eliminating the use of smokeless and spit tobacco products.”
The zinger that Zeller focused on, however, was this: “Each year in the U.S., more than 2,300 people are diagnosed with oral, esophageal and pancreatic cancer due to smokeless tobacco use.”
I recently called on the CDC to release long-suppressed smokeless tobacco data (here). The agency remains opaque on the matter, but Zeller did offer that one hard number. Now we must ask: Is it accurate?
Surprisingly, the only source reference for the figure is found in the agency’s Tweet, here, which points to a 558-page report by the National Cancer Institute and the CDC (here). The 2,300 figure, appearing on page 135, is the result of a calculation by Jane Henley and Michael Thun, epidemiologists at the CDC and the American Cancer Society. They estimate that each year smokeless tobacco causes 1,601 oral cancers, 184 esophageal cancers and 530 pancreatic cancers, totaling 2,315.
Drs. Henley and Thun estimated the number of current smokeless users in the U.S., and then applied relative risks (RR) from American studies of smokeless tobacco compiled by a 2008 article by Paolo Boffetta (here) – which I previously showed to be a classic case of data cherry picking (here).
Henley and Thun’s report of 700+ cases of esophageal and pancreatic cancers is unsubstantiated, as Boffetta’s RRs for these diseases among American smokeless users are not statistically significant.
Boffetta reported an elevated RR of 2.6 (95% confidence interval = 1.3 – 5.2) for oral cancer among American smokeless users, but his risk analysis used only six studies, with no explanation of inclusion criteria. The following table provides details about his results.
|Epidemiologic Studies Used by Boffetta for U.S. Summary Risk Estimate = 2.6 (1.3 – 5.2), Smokeless Tobacco and Oral Cancer (Lancet Oncology, 2008)|
|Source Study (Author, Journal Year)||Includes smokers||Product, Number of Cases in Users||Relative Risk (95% Confidence Interval)|
|Mashberg, Cancer 1993||Yes||Dip-Chew, 52||0.8 (0.4 – 1.9) Dip|
|1.0 (0.7 – 1.4) Chew|
|Kabat, International Journal of Epidemiology 1994||No||Chew, 4||2.3 (0.7 – 7.3)|
|Henley, Cancer Causes and Control 2005||No||ST, 4||2.0 (0.5 – 7.7) CPS-I cohort|
|ST, 1||0.9 (0.1 – 6.7) CPS-II cohort|
|Winn, New England Journal of Medicine 1981||No||Dry Snuff, 79||4.2 (2.6 – 6.7) Whites|
|Dry Snuff, 12||1.5 (0.5 – 4.8)|
|Blot, Cancer Research 1988||No||Dry Snuff, 6||6.2 (1.9 – 19.8)|
|Kabat, International Journal of Epidemiology 1994||No||Chew, 0||0|
|Men and Women Combined|
|Stockwell, Head and Neck Surgery 1986||Yes||ST, Men, 1: Women, 0||2.3 (0.2 – 12.9) Tongue|
|ST, Men, 3; Women, 2||11.2 (4.1 – 30.7) Other Mouth|
|ST, smokeless tobacco unspecified|
|CPS I and II, American Cancer Society surveys|
Some of the studies referenced by Boffetta included smokers, who are at much higher risk for oral cancer. Additionally, men who dipped or chewed had no risk for oral cancer in any of the studies. Boffetta’s elevated risk estimate of 2.6 was based almost entirely on women in the Winn and Blot studies. As I have explained (here), elevated oral cancer risk among women in those studies was due to use of powdered dry snuff (here). The table clearly shows the difference in risk between powdered dry snuff used by women and the dip/chew products used by men. Boffetta’s estimate should never be applied to men who dip and chew.
Unbiased epidemiologists would be appalled to learn that the FDA is basing its smokeless campaign on population cancer estimates derived from unreliable and inappropriate RRs.
Even if the FDA’s claim of 2,300 smokeless-related cancers was accurate, the number would pale in comparison to the 480,000 U.S. deaths per year due to smoking.
To deal with The Real Cost of tobacco use, the FDA should publish an honest estimate of the risks and consequences of smoking and smokeless use, and issue public messages that inform rather than mislead. The current campaign wastes taxpayer resources, obfuscates the truth about smokeless tobacco and, ultimately, denies smokers information that could save their lives.