Reading the headline, you would be forgiven for believing that there was a proven causal link between smoking - actively or passively - and childhood asthma. Whilst research suggests this may be the case, it's not quite so straight forward.
A rich source of asthma-related information, the website www.asthma.org.uk states "It's difficult to know for sure what causes asthma". It continues:
"What we do know is that you're more likely to develop asthma if you have a family history of asthma, eczema or allergies. It's likely that this family history, combined with certain environmental factors, influences whether or not someone develops asthma.
Whist the statistics demonstrate children whose parents smoke are more likely to develop asthma - particularly for those children whose mothers smoked whilst pregnant - there is little evidence to suggest passive smoking is a major contributory factor. (You will doubtless have noticed the quote above fails to mention smoking at all.)"Many aspects of modern lifestyles - such as changes in housing and diet and a more hygienic environment - may have contributed to the rise in asthma over the past few decades. Environmental pollution can make asthma symptoms worse and may play a part in causing some asthma."
The prevelance of asthma increased in the majority of countries across the world (including the UK) since the 1970s, although levels appear to have plateaued in some developed countries. Indeed, self-reported symptoms of asthma in children 13–14 years of age decreased by about 20% in the UK between 1995 and 2002 [Anderson, 2005] (before the smoking ban!).
Nor can the increased prevelance of asthma be explained by any links with passive smoking. Throughout the last four decades, the number of smokers (and children living in households where there is at least one parent who smokes) has steadily and consistently fallen. Furthermore, the level of harmful substances per cigarette has also fallen steadily in recent years, with levels of tar and nicotine, for example, less than one third of what they were half a century ago.
Even if we accept, for the sake of argument, that passive smoking is the primary contributory factor in severe childhood asthma, it is difficult to see how the smoking ban could have led to the fall in admissions as has been claimed.
The smoking ban was introduced primarily to protect staff in the workplace; mainly in pubs and restaurants, but not exclusively so. Whilst it may be different in your place of work or local pub, these aren't places where I have ever seen large numbers of children hanging out.
The argument as reported on the BBC website, that the smoking ban has lead to a fall in severe childhood asthma, appears to amount to little more than post hoc, ergo propter hoc - after it, therefore because of it (as any latin scholar or fan of the West Wing can tell you). As often proves to be the case, this is likely to prove a nonsense.
Whilst it is obviously in the interests of those nannying fussbuckets responsible for the introduction of the smoking ban to try and further 'evidence' of the benefits of the ban (other than the 1,000s of pubs forced to close since 2007), this is a pretty lazy effort by any standards.
As H Ross Anderson, professor of epidemiology and public health, stated in his 2005 article:
"Any advance in our understanding of trends is likely to depend on the development of new theories of causation together with better methods of measuring and classifying asthma in population studies."Until such time as we have not just developed new theories but have proven the causations of asthma, you will forgive me if I treat any such claims by the anti-smoking lobby with a healthy pinch of cynicism.
In the meantime, I'm sure the BBC will continue to do what the BBC does, and not let the facts or balance get in the way of a 'story'...
Highly recommended further reading from Simon Cooke's blog: http://theviewfromcullingworth.blogspot.co.uk/2013/01/how-to-lie-with-statistics-asthma.html
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