After Scotland implemented a smoking ban in enclosed public places in 2006, cases of childhood asthma have dropped by an average of 18% per year, Glasgow University researchers have revealed in an article published in the New England Journal of Medicine (NEJM). Up to 2006, asthma hospital admission rates had been rising by 5.2% per year for children aged up to 15 years.

The authors reveal that benefits have emerged in both school-age and pre-school children. These findings are completely the opposite to what critics predicted - they feared parents would smoke more at home if they could not do so in pubs, at work or other enclosed public places.

Dr. Jill Pell, University of Glasgow, Scotland, one of the investigators, confirmed that the effect was the opposite to what critics said would happen. She added that people are now accepting that nonsmokers and children need to be protected from tobacco smoke. The legislation was, in fact, followed by more voluntary restrictions on household smoking.

Reductions in asthma-related hospital admissions since 2006 were: 18.4% among preschool children 20.8% among school-age children The authors wrote that previous studies had revealed a drop in respiratory problems among bar staff, including those who smoke.

Dr. Pell and team gathered data on childhood asthma hospital admissions and asthma deaths dating from the beginning of 2000 up to October 2009, during which five children died of asthma. During that period there were 21,415 childhood asthma related hospital admissions (aged up to 15 years).

From 2000 to 2002 the number of admissions dropped slightly, and then started to rise, peaking in 2006 when the new legislation came into force. From 2006 onwards hospitalization rates started to plummet.

The researchers could not determine whether the drop in asthma hospitalization rates were due to less smoke in enclosed public places or at home. They added that a drop in smoking among schoolchildren could also have been a contributory factor - smoking among schoolchildren dropped from 5% among 13-year-old schoolboys in 2004 to 3% in 2007.

The authors wrote that overall tobacco smoke exposure among schoolchildren was determined by measuring cotinine concentrations in their saliva.

The authors concluded:

In Scotland, passage of smoke-free legislation in 2006 was associated with a subsequent reduction in the rate of respiratory disease in populations other than those with occupational exposure to environmental tobacco smoke. What is asthma? Asthma is a disease affecting the airways that carry air to and from your lungs. People who suffer from this chronic condition (long-lasting or recurrent) are said to be asthmatic.

The inside walls of the airways of a person with asthma are swollen or inflamed. This swelling or inflammation makes the airways extremely sensitive to irritations and increases your susceptibility to an allergic reaction.

As inflammation causes the airways to become narrower, less air can pass through them, both to and from the lungs. Symptoms of the narrowing include wheezing (a hissing sound while breathing), chest tightness, breathing problems, and coughing. Asthmatics usually experience these symptoms most frequently during the night and the early morning.

Click here to read about asthma in more detail. What is secondhand smoke? Secondhand smoke, also known as passive smoking is the inhalation of tobacco smoke by a non-smoker; the environmental smoke comes from other people's cigarettes, pipes or cigars. The environmental tobacco smoke is inhaled involuntarily or passively by somebody who is not smoking. ETS stands for environmental tobacco smoke.

"Smoke-free Legislation and Hospitalizations for Childhood Asthma"
Daniel Mackay, Ph.D., Sally Haw, B.Sc., Jon G. Ayres, M.D., Colin Fischbacher, M.B., Ch.B., and Jill P. Pell, M.D.
N Engl J Med 2010; 363:1139-1145September 16, 2010