Day Care Doesn't Protect Against Asthma
Findings Challenge 'Hygiene Hypothesis'
Day Care: No Lasting Impact on Asthma continued...
By the age of 8, there was no difference in asthma-related symptoms like wheezing in children who had early day care and those who did not.
No difference in wheeze was seen with regard to day care attendance among boys and girls, but having older brothers or sisters did impact risk.
Children with older siblings who started day care early had more than a fourfold higher risk of frequent respiratory infections and a more than twofold risk of wheezing in the first year of life compared to children without older siblings who did not attend day care.
But even in these high-exposure children, no difference in asthma-related symptoms was reported by age 8.
7 Million Kids U.S. Kids Have Asthma
Supporters of the hygiene hypothesis say it could help explain the dramatic increase in allergy and asthma in industrialized countries during a time when exposure to germs has declined.
Asthma is now the most common chronic disease of childhood, affecting close to 7 million children in the U.S., according to the American Lung Association.
Many studies examining the hygiene hypothesis have focused on day care attendance because children who go to day care tend to be exposed to more germs and infections.
Findings have been mixed, with some studies suggesting a protective role for day care attendance and others failing to show a benefit.
The new research is one of the largest studies ever to address the question, with some of the longest follow up.
But asthma specialist John Mastronarde, MD, tells WebMD that an even longer follow up would be needed to conclusively show that early day care attendance has no lasting impact on asthma risk.
Mastronarde directs the asthma center at Ohio State University Medical Center.
“This study adds another interesting piece to the puzzle, but I don’t see it as definitive,” he says.
He says it is increasingly clear that rather than being a specific disease with one specific cause, asthma is a heterogeneous disorder with many different triggers.
Asthma researcher Clare Ramsey, MD, agrees the new study is not definitive.