Tuesday, October 14, 2008

CDC Press Release Suggested that Short-Term Secondhand Smoke Exposure Can Trigger Heart Attacks in Healthy Persons

A 2004 press release issued by the Centers for Disease Control and Prevention (CDC) suggests that brief secondhand smoke exposure can trigger heart attacks, even among healthy individuals.

The headline of the press release states: "Short-Term Secondhand Smoke Exposure May Trigger Heart Attacks."

The only relevant section of the text of the press release states: "Even short-term exposures -- lasting as little as 30 minutes -- may pose significant risks, especially in persons who already have or are at special risk of heart disease."

The Rest of the Story

The claim made in the headline of the press release is not qualified. That is, it clearly suggests that short-term secondhand smoke exposure may trigger heart attacks in anyone, not just someone who has severe, pre-existing coronary artery stenosis. Thus, the headline suggests to the media that a short exposure to secondhand smoke is sufficient to cause a heart attack in a healthy individual.

In the text of the press release - the only place where the headline's claim is discussed - it states that as little as 30 minutes of exposure poses significant risks, especially in persons with pre-existing heart disease. The inclusion of the word "especially" implies that the significant risks being discussed also apply to healthy individuals.

Thus, taking the press release as a whole, it seems to be suggesting that a mere 30 minutes of secondhand smoke exposure is enough to cause a heart attack in a healthy individual.

This is impossible. A healthy individual cannot suddenly develop heart disease in 30 minutes. To someone without severe heart disease, a 30-minute exposure is not going to trigger a heart attack. So the press release is very misleading.

The rest of the story, then, is that the 30-minute heart attack claim appears to have come, at least in part, from the CDC and its 2004 press release, which suggested to the media that brief secondhand smoke exposure can trigger a heart attack in a healthy individual.

It appears that this press release was what resulted in the widespread media misrepresentation of the science to the public. Headlines throughout the country warned the public that if they are exposed to secondhand smoke even briefly they could drop dead from a heart attack. Most of the coverage of the CDC's statement did not qualify the claim, clearly implying to the public that 30 minutes of secondhand smoke exposure can cause a heart attack in even a healthy individual without pre-existing heart disease (or with very mild heart disease).

For example, this article from CNN stated: "According to the CDC, exposure to secondhand smoke for as little as 30 minutes can significantly increase your risk of heart attack." Note that the article stated: "increase your risk," not "increase the risk for someone with severe, pre-existing heart disease."

The difference between these is huge. In fact, it is the difference between true and false. It is the difference between accurately communicating science to the public and wildly misleading the public with exaggerated, unsupported scientific claims.

Unfortunately, it may also be the difference between having a public that trusts public health officials and one which discounts what it hears because it is used to receiving exaggerated and distorted information.

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