According to the first systematic review and meta-analysis examining the effect of smoke-free legislation on child health, rates of both preterm births and hospital attendance for asthma were reduced by 10 per cent within a year of smoke-free laws coming into effect. (Agencies)
The analysis, published in The Lancet, included 11 studies done in North America and Europe, involving more than 2.5 million births, and nearly 250,000 asthma exacerbations.
Currently only 16 per cent of the world's population is covered by comprehensive smoke-free laws, and 40 per cent of children worldwide are regularly exposed to second-hand smoke.
To date, most studies have looked at the impact of smoking bans on adult outcomes, but children account for more than a quarter of all deaths and over half of all healthy years of life lost due to exposure to second-hand smoke.
Researchers searched systematically for both published and unpublished studies over 38 years (1975-2013) reporting on the impact of public smoking restrictions on health outcomes in children aged 12 years or younger.
Dr Jasper Been from the Maastricht University Medical Centre, in the Netherlands, and colleagues identified 11 suitable studies - five North American studies describing local bans and six European studies looking at national bans.
"Our research found significant reductions in preterm birth and severe asthma attacks in childhood, as well as a 5 per cent decline in children being born very small for gestational age after the introduction of smoke-free laws," said Been.
"This research has demonstrated the very considerable potential that smoke-free legislation offers to reduce preterm births and childhood asthma attacks," said study co-author Professor Aziz Sheikh, of Brigham and Women's Hospital, US, and the University of Edinburgh, UK.
"The many countries that are yet to enforce smoke-free legislation should in the light of these findings reconsider their positions on this important health policy question," Sheikh said.
Writing in a linked comment, Sara Kalkhoran and Stanton Glantz from the University of California San Francisco in the US said, "Medical expenses for asthma exceeded USD 50 billion in the USA in 2007, and USD 20 billion in Europe in 2006."
"If asthma emergency department visits and admissions to hospital decreased by even 10 per cent, the savings in the USA and Europe together would be USD 7 billion annually," they said.
According to the first systematic review and meta-analysis examining the effect of smoke-free legislation on child health, rates of both preterm births and hospital attendance for asthma were reduced by 10 per cent within a year of smoke-free laws coming into effect.