Thursday, May 18, 2006

Great science headlines of the world

My SO spotted this headline on CNN a few days ago:

Now, what does that headline mean? My guess is that due to all the anti-smoking literature available, most people will immediately pair the group "nonsmoking men" with "smoking men", and thus think that the article is reporting that smoking really isn't all that bad for you.

It turns out that the study being reported on (Thun et al. 2006) compares cancer rates of nonsmoking men to those of nonsmoking women; CNN's first two paragraphs clear this up quickly:
Lung cancer isn't common in people who never smoked. But when they do get it, doctors have long thought that women were more likely to die than men. New research suggests the opposite.

Analyzing medical records of nearly 1 million people, American Cancer Society researchers reported Tuesday that men who never used cigarettes actually had slightly higher death rates from lung cancer than women who never smoked.
OK, so now everything looks clear - the study is actually showing that nonsmoking men are more likely to die of cancer than nonsmoking women, contrary to popular belief. Well, once again the CNN article appears to be misrepresenting things, as the summary of the journal article on the journal's homepage reports the following:
Women nonsmokers are equally likely to die from lung cancer as men, but nonsmoking African American women may be at higher risk of lung cancer death than white women.
The abstract of the article does indeed report that men have a higher reported incidence of cancer, but my guess is that this higher incidence is not statistically significant (I don't have access to the full text of the article, so can't confirm this), and thus shouldn't be reported on.

So, a more accurate headline would have been, "Nonsmoking women not more likely to die of cancer than nonsmoking men." Guess that wouldn't have gotten as many clickthroughs.

Thun MJ, SJ Henley, D Burns, A Jemal, TG Shanks, and EE Calle. 2006. Lung Cancer Death Rates in Lifelong Nonsmokers. J Natl Cancer Inst 98:691-699. (Abstract)

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