During the last couple of decades, public smoking bans in the US and Europe have come into effect. Now, the first systematic review and meta-analysis to examine the effect of this smoke-free legislation on child health shows these bans have been followed by decreasing rates of preterm births and children attending the hospital for asthma.
The analysis has been published in The Lancet and assesses 11 studies conducted in North America and Europe. In total, this involves over 2.5 million births and 250,000 asthma aggravations.
Researchers from the study say that, worldwide, 40% of children are regularly exposed to secondhand smoke, "which is of great concern because they are generally unable to influence their own level of exposure."
Additionally, smoking kills an estimated 5.7 million people each year, so the team emphasizes that effective tobacco control is key in reducing global mortality rates.
Though public smoking bans have helped certain areas of the globe cut down on exposure to second-hand smoke, the researchers say only 16% of the world's population is covered by comprehensive smoke-free laws.
Prior to this latest analysis, most studies have only focused on how smoking bans have affected adult outcomes, but the team says children account for more than a quarter of all deaths and more than 50% of all healthy years of life lost due to exposure to secondhand smoke.
As such, the researchers searched for both published and unpublished studies between 1975 and 2013 - spanning 38 years - that reported on the impact of public smoking restrictions on health outcomes in children aged 12 years or younger.
In total, there were 11 studies that matched their criteria - five from North America describing local bans and six from Europe describing national bans.
'Smoking bans have considerable public health benefits'
Overall, the team found that rates of both preterm births and hospital attendance for asthma were reduced by 10% within a year of smoking bans being put in place.
The analysis showed a link between initiation of public smoking bans and a decrease in preterm births and hospital visits for children with asthma.
Additionally, their research revealed that after the smoke-free laws were established, there was a 5% decline in children being born very small for gestational age.
Dr. Jasper Been, study author from the Maastricht University Medical Centre in the Netherlands, says:
"Together with the known health benefits in adults, our study provides clear evidence that smoking bans have considerable public health benefits for perinatal and child health, and provides strong support for WHO [World Health Organization] recommendations to create smoke-free public environments on a national level."
Quite a bit of research has been published recently uncovering the detrimental effects of secondhand and even thirdhand smoke - exposure to the toxic compounds of tobacco smoke from surfaces and even dust in a room where someone has smoked previously.
Medical News Today recently reported on a study that suggested thirdhand smoke damages DNA and may cause cancer. And another study suggested this type of exposure is linked to liver, lung and skin problems.
Regarding the latest analysis, Prof. Aziz Sheikh, co-author from Brigham and Women's Hospital in the US and the University of Edinburgh in the UK, says:
"This research has demonstrated the very considerable potential that smoke-free legislation offers to reduce preterm births and childhood asthma attacks. 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."
In a linked comment to the study, Sara Kalkhoran and Stanton Glantz, both from the University of California San Francisco, say that asthma medical expenses in the US totalled more than $50 billion in 2007 and $20 billion in Europe in 2006.
"If asthma emergency department visits and admissions to hospital decreased by even 10%," they write, "the savings in the USA and Europe together would be $7 billion annually."