The researchers from the UK Centre for Tobacco Control Studies, based at the University, found there was an immediate 4.9 per cent reduction in emergency hospital admissions for asthma in the adult population. This implies almost 1900 admissions were prevented during the first year after legislation was introduced and a similar number in the subsequent two years.
In order to investigate the law that made enclosed public places and workplaces smoke-free in England from 1 July 2007 onwards, the study, funded by the Department of Health and published this week in the journal Thorax, identified monthly numbers of emergency admissions for asthma from April 1997 to December 2010 in the population aged 16 and over.
Admission rates in the ten years before the introduction of smokefree legislation were then compared to those in the period after it came into force, taking into account underlying trends in admissions and variations in other factors liable to influence asthma admission rates, such as seasonal flu and temperature.
Dr Michelle Sims, the first author of the paper, said: “Second hand smoke exposure has significant adverse health effects on the adult respiratory system with current evidence suggesting that it contributes to the onset and exacerbation of asthma.
“There is already evidence that smokefree legislation in England is associated with reductions in secondhand smoke exposure among non-smoking adults and fewer emergency hospital admissions for heart attacks and childhood asthma. Our findings show that these health benefits extend to adult asthma.”
The prevalence of asthma in England is among the highest in the world with approximately 5.9 per cent of the population having the condition.
There are furthermore stark regional differences in emergency hospital admissions for asthma across England that have widened in recent years.
Professor Anna Gilmore, who led the study, said “Our findings add to the expanding body of evidence that smokefree policies are associated with positive health outcomes.”
Only four previous studies have examined whether the introduction of smokefree legislation was associated with immediate reductions in asthma admissions among adults and collectively these findings are inconclusive. This paper, the largest study of its kind and addressing limitations of previous studies, makes a unique contribution to the evidence on smokefree laws and asthma.
The full results are reported in the paper Short-term impact of the smokefree legislation in England on emergency hospital admissions for asthma among adults published in the journal Thorax.
University of Bath, Bath, BA2 7AY, UK