Thursday, May 6, 2010

Anti-smoker hijinks? A case of disappearing data

I spend a lot of time surfing the web, researching articles for this blog. I want to be as accurate as possible in the information I present to any readers who happen by and linger long enough to actually read what I write. I don't always get it right and I readily admit to a measure of bias in my interpretation of some of the evidence.

Part of the problem is the inconsistency in the evidence, or, more precisely, the interpretation of the evidence.

For example, I don't have hair growing on the palms of my hands and my vision is 20-20. One could conclude from that evidence that: a) I have never engaged in self-gratification, or; b) Masturbation does not cause hairy hands or blindness.

And, despite the claims of the anti-smoker cult, the scientific evidence on smoking and secondhand smoke is also open to interpretation; like most science, it's tentative, rather than definitive.

In 2004, the Surgeon General of the US added uterine cervical cancer to the list of those for which evidence was allegedly sufficient to conclude a causal relationship between smoking and the disease. Health Canada used the claim to justify the addition of cervical cancer to their list of smoking related diseases. Their 2007 SAMMEC report (Smoking Attributable Morbidity and Mortality Economic Costs) claims that 126 of 382 deaths (34.7%) from cervical cancer were caused by smoking.

As it turns out, there is even stronger evidence to suggest that HPV, not smoking, is the cause of most, perhaps all, cases of cervical cancer.

In fact, the Health Canada website (now) states unequivocally that: “HPV causes almost all cases of cervical cancer.” They also note that: “Infection with human papillomavirus (HPV) increases your risk [of cervical cancer] 20 to 100 times.”

Even the Canadian Cancer Society (still) admits: “The most important risk factor for developing cervical cancer is infection of the cervix with human papillomavirus.”

Both of these claims appear to exonerate smoking as a cause of cervical cancer. Of course, I don't recall any news headlines proclaiming: “HPV, not smoking, is the sole cause of cervical cancer.”

But, have Health Canada and the Canadian Cancer Society tempered their argument that HPV is the single most significant cause of cervical cancer to appease the more rabid elements of the anti-smoker cult? I would argue that may be the case.

On September 2, 2009, I wrote a blog entry where I referenced material from Health Canada and the Canadian Cancer Society. Here's the information I provided in that article:

“According to Health Canada, persistent HPV infection with high risk types, is the major cause of cervical cancer. It is estimated that over 99% of cervical cancers are caused by HPV.

This contention is supported by the Canadian Cancer Society: “Nearly all cervical cancers are caused by persistent high-risk HPV infection. High-risk types of HPV are considered known cancer-causing agents. About 70% of cervical cancers are associated with high-risk HPV type 16 and 18. Other high-risk types of HPV are associated with the other 30% of cervical cancers.”


At the time of writing, both claims appeared on their respective web sites. It is my practice to cut and paste comments or quotes I plan to use directly into my rough drafts, along with the hyper-link to the article. I'm confident that both statements were accurately reported in my article.

However, two weeks ago, a belated comment to my September post claimed that the Health Canada website did not contain the information purported in my article and the Canadian Cancer Society page didn't exist.

It is not unusual for links to newspaper articles to disappear; sometimes articles are archived after only a few weeks. However, web sites, more often than not, remain static unless, and until, the content contained therein requires change based on new or updated information.

At any rate, the Health Canada site no longer makes the claim that “over 99% of cervical cancers are caused by HPV”. That's been downgraded to “HPV causes almost all cases of cervical cancer.” And, the Health Canada site now contains the cryptic comment that: “In some studies, cigarette smoking has been found to increase the risk.” Uh-huh.

Of course, if the risk from HPV is “20 to 100 times” greater, it's hard to see how the additional risk of 1.9 from smoking will increase that risk to any significant level. Did Health Canada bow to pressure from their colleagues in the anti-smoker brigade and alter the content of their web page? Or, did they simply recognize that if HPV caused 99% of cervical cancer, then their claim that 126 of 382 deaths (34.7%) from cervical cancer were caused by smoking was, in diplomatic terms, grossly overstated?

The Canadian Cancer Society simply deleted the whole damn page. Follow the link and you get a blank page with the CCS logo and a notice that says: “Content not available at this time. Sorry, content is not available in English.”

Now, this could mean one of two things; a) The page content has been removed for revision and may, or may not, be available at a future date, or; b) The information is provided only in Canada's other official language.

It's not available in French either. I checked; just to be sure.

Both Health Canada and the CCS have an obligation to provide the public with accurate, reliable information. And, they may have a perfectly logical explanation for removing the information from their respective sites.

But . . .

It will be interesting to hear what Health Canada and CCS have to say about this strange occurrence. But, I don't think I'll hold my breath waiting for the explanation.

4 comments:

Ann W said...

You can still view the Canadian Cancer Society's website using the following quote in a google search

“Nearly all cervical cancers are caused by persistent high-risk HPV infection. High-risk" the clicking on the cashed version.

Ann

The Old Rambler said...

Ann W,

Thanks for the tip. I've downloaded and saved the cached page as an HTML file for future reference.

It will be interesting to read any explanation CCS might provide for the change. Assuming, of course, that I get one.

Matt

Anonymous said...

Bullshit

The Old Rambler said...

Dear Anonymous,

That you so much for the thought provoking critique. I found it very enlightening, though a little rambling and incoherent. I'll leave you with a bit of advice I got from my grand-father many years ago: “When you have nothing to say; say nothing.”