Adoption of smoke-free legislation reduces childhood asthma

We’ve known for a long time that tobacco smoke causes asthma exacerbations in children. And it doesn’t have to be the actual smoke; for children with asthma, simple exposure to rooms where people have smoked, or even to the clothing of smokers, can trigger breathing problems. A principal argument for banning smoking in public places is that these environments can be downright toxic for asthmatics. Do these anti-smoking regulations actually work? The bottom line question would be this: after these laws are passed, is there any change in the number and severity of asthma attacks? An important recent report in the New England Journal of Medicine gives us an answer. Yes — these regulations help children breathe better.

The research was done in Scotland, where all smoking at enclosed public places was banned in 2006. The premise of the study was simple: look at how many children were hospitalized for asthma before the ban and afterward. The results were striking: throughout Scotland, there was a reduction of asthma admissions in children of 15%. That may not seem like much, but the ban had only been in effect for 3 years when the data were collected. The direction of the trend line strongly indicates that there will be further reductions.

It’s important to understand that correlation doesn’t imply causation. That is, there’s no way to know if the drop in asthma attacks was really caused by the ban. But the authors did a large number of adjustments and corrections to the data set to rule out confounding variables (such as rural/urban, socioeconomic status, age, severity of previous asthma attacks). The reduction occurred in children of all ages — toddlers up through school-age.

The link above is only to the abstract of the article (you need a subscription to get the full text), but the key figures are there in the abstract. If anyone wants the complete article and can’t get it, let me know.