Wednesday, June 25, 2008

Authors of Flawed Study to Smoking Parents: If You Don't Want to Quit, Don't Bother Being Careful to Smoke Outside the Home; It Won't Help

The authors of the study discussed here yesterday which concluded that parents who smoke only outside the home still expose their children to dangerously high levels of tobacco smoke have instructed the public that there is no reason to smoke outside in an effort to protect children from secondhand smoke. As quoted in an article in the Victoria Herald-Sun, the authors told the public that smoking outside the home is pointless; the only way to protect children from tobacco smoke exposure is not to smoke at all.

According to the article: "Lead researcher Dr Krassi Rumchev said when smokers returned indoors, they still breathed out smoke that contaminated the air enough to cause damage. They also brought particles inside on their body and clothes. Dr Rumchev said parents must quit to make their home safe for children. 'If parents would like to provide a smoke-free home environment they have to stop smoking,' Dr Rumchev said. 'Smoking outside just isn't providing the protection that many Australian smokers believe it does.'"

The Rest of the Story

As I explained yesterday, this study is severely and fatally flawed because no effort was made to confirm the self-reported assertions of parents that they only smoke outside the home. The most likely explanation of the study results is not that outdoor smoking causes indoor exposure because of contaminated breath, but that a proportion of the smokers who claimed only to smoke outside were actually lying or stretching the truth and that they do sometimes smoke in the home. The authors of the study dismissed this possibility without any evidence to support that it is not a reasonably likely explanation for the study findings.

This article demonstrates what I predicted yesterday: that anti-smoking advocates will use this flawed study to send the message that parents need not bother to try to refrain from smoking inside the home. It is all or nothing. Either quit smoking completely or you might as well just puff in the faces of your children.

Obviously, this message is nonsense. Of course, quitting is the healthiest option for both the parents and their children. But for the many smokers who either do not want to quit or cannot do so, smoking outside is clearly a much better option than smoking inside the home. And the study in question actually provides no evidence that smoking outside the home is not adequate to protect children from substantial exposure to tobacco smoke inside the home.

To me, this recommendation is irresponsible. If you are going to go out on a limb and make a risky recommendation - one that could endanger the health of many children if it turns out to be wrong - then I think you have the responsibility to make reasonably sure that you are right before you make that recommendation. Here, the authors have failed to do that. They have no evidence to back up their assumption that smokers are all telling the truth. They have not confirmed that all the smokers who claimed to only smoke outside (which was all but 4 of the 39 households) are being truthful, rather than trying to conform to what they see as societal standards or norms.

In public health as in medicine, I believe our first responsibility is to do no harm. Here, I believe that this recommendation from the study authors may well do harm. It may harm children by convincing a number of parents who might otherwise smoke outside that there is no sense to doing so. The end result could well be increased exposure for many children.

If you are going to make a recommendation like this, then you better be reasonably sure that your assumptions are correct. In this case, the authors of the study have made no effort to ensure that their chief assumption - that all study subjects were telling the truth - is correct.

Thus, the rest of the story is that these authors' advice is not only wrong, it is irresponsible.

(Thanks to Michael J. McFadden for the tip).

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