Pfizer (NYSE: PFE) got more bad news for smoking cessation aid Chantix this week. A paper published in the Canadian Medical Association Journal suggests that Chantix increases the risk of cardiovascular events in patients without a history of heart disease. The new data piles on last month's Food and Drug Administration warning about the potential increase in patients with cardiovascular disease.

Researchers combined data from 14 clinical trials to find that Chantix increases the rate of cardiovascular events -- heart attacks, strokes, and the like -- by 72%. While that sounds awfully bad, we have to keep this in context. The rate only increased from 0.82% for people taking placebo to 1.06% for patients taking Chantix. If the data is correct -- and there are certainly issues with doing this type of meta-analysis -- for every 400 or so people without cardiovascular risk, Chantix creates one additional cardiovascular event.

Of those 400 patients, about 80 will quit for an entire year compared to around 30 for those on placebo. Are the health benefits of 50 smokers quitting greater than one cardiovascular event? I'd guess yes, but calculating it would require yet another meta-analysis, and we're already on a slippery slope drawing any conclusions here.

Pfizer's best hope for Chantix is that patients ignore the warning section on the drug's label, which may be updated at some point to contain the new cardiovascular risk. Given that smokers have been disregarding cancer warning labels on cigarettes sold by Reynolds American (NYSE: RAI), British American Tobacco (AMEX: BTI), Altria (NYSE: MO), and others for years, the smoking cessation aid would seem to have a decent shot at retaining sales.

If not, GlaxoSmithKline (NYSE: GSK) and its multiple smoking cessation aids would seem to be the likely beneficiary. Assuming, of course, patients don't just shun the aids altogether and turn to sheer willpower to kick the habit.

Fool contributor Brian Orelli doesn't hold a position in any company mentioned in this article. Click here to see his holdings and a short bio. The Motley Fool owns shares of Altria Group and GlaxoSmithKline. Motley Fool newsletter services have recommended buying shares of GlaxoSmithKline and Pfizer. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.