Monday, 21 January 2013

The English asthma miracle

The BBC has reported the latest heart-warming news about the English smoking ban...

There was a sharp fall in the number of children admitted to hospital with severe asthma after smoke-free legislation was introduced in England, say researchers.

A study showed a 12% drop in the first year after the law to stop smoking in enclosed public places came into force.

The implication is that this is the result of reduced secondhand smoke exposure. Of course, the smoking ban mainly affected places where children don't go, ie. workplaces, pubs and clubs, so the authors suggest that the smoking ban inspired people to make their own homes "smokefree" of their own volition.

The lead researcher, Prof Christopher Millett, said the legislation has prompted unexpected, but very welcome, changes in behaviour.

"We increasingly think it's because people are adopting smoke-free homes when these smoke-free laws are introduced and this is because they see the benefits of smoke-free laws in public places such as restaurants and they increasingly want to adopt them in their home.

"This benefits children because they're less likely to be exposed to second hand smoke."

Regular readers will know that studies of this sort have a tendency to be refuted by publicly available hospital admissions data. Actually, that's an understatement. In every single instance when the hospital admissions data are available, studies of this sort have not stood up. I'll discuss the mind-boggling methodology of this study (of which Stanton Glantz is an author) tomorrow, but for now here's the data from England's Hospital Episode Statistics which do not appear to support the claims being made.

Shown below are the number of hospital admissions for asthma (ICD code J45) since 2000/01. The figures shown are for the 0-14 year age group studied in the new study. The smoking ban began in July 2007. Click to enlarge.



Out of curiosity, I also looked at the number of asthma admissions for all age groups.



Regarding emergency admissions, it worth recalling the announcement from Asthma UK in 2010...

Asthma UK said the number of emergency admissions had remained unchanged for a decade

They were referring to Scotland in that instance, but that did not prevent claims of a Scottish asthma miracle being made. It may be that the situation in England is radically different from that in Scotland, and it may be that the trend in emergency admissions data differs radically from that of finished consultations. But, as we shall see tomorrow, it isn't.


(Please note that this post originally said the admissions were consultations. The graphs still do. In fact, the 0-14 year old graph shows admissions and the all ages graph shows emergency admissions. Thanks to BrianB for pointing out the error.)