Childhood Pets Linked to Lower Allergy Risk

From Reuters Health Information

NEW YORK (Reuters Health) Jul 22 - Good news for families that would love to have a furry dog or cat but hesitate for fear the kids might become allergic: Fido or Kitty might actually be good for children's health, scientists say.
They found that children who were exposed to animals at a young age had lower rates of nasal allergies as adolescents.
"Family pets, in particular dogs...need not be removed to prevent allergies, and in fact may protect against them," Melanie Matheson of the University of Melbourne, lead author of the study, told Reuters Health in an email.
Looking at survey responses from nearly 8,500 adults from Europe and Australia, Matheson and colleagues focused on those who grew up around house pets or farm animals, and those who had the troublesome runny noses, itchy eyes, and sore throats that plague nasal allergy sufferers.
Growing up with pets has already been linked to a lower risk of other types of allergies. A 2010 study from the University of Cincinnati showed than owning a dog may decrease the risk of childhood eczema, a skin condition (see Reuters Health story of October 13, 2010). Similarly, a 2011 study from Henry Ford Hospital in Detroit found that growing up with pets cut kids' risk of developing pet allergies by half.
In the new study, published online July 13th in the Journal of Allergy and Clinical Immunology, more than one in four respondents said they had nasal allergies. In most cases, people said their allergies started when they were adolescents.
A number of factors were linked to a higher risk of nasal allergies in the study. Some, like a family history of allergies and the mother smoking while pregnant, are well documented risk factors.
But the research team also found that small children who had lots of exposure to other little kids - because they had young siblings, for instance, or attended day care - had lower risks of nasal allergy. And the more siblings a child had, the lower the odds that the child would have nasal allergies later in life.
The scientists saw a similar pattern among people who grew up on a farm or had pets before age five. Compared to rates in people who didn't have those experiences in early childhood, the odds of having nasal allergies in adolescence were 30% lower in people who grew up on a farm, while having a dog and cat were each associated with a 15% reduction.
Furthermore, people who'd had siblings and animal exposure had lower rates of nasal allergies compared to those who'd had only one or the other experience.
These results were consistent in the 13 countries surveyed, "despite the differences in pet ownership and farming between countries," Matheson told Reuters Health in an email.
The study design cannot prove that exposure to pets or other children are the cause of the lower risk of nasal allergies. Although the authors accounted for several factors, including education and family history of allergies, there may be another cause of the reduced nasal allergy risk that is associated with pets and siblings.
Also, the researchers only had information on exposure to animals before age five, so they don't know whether being around animals at an older age would have any effect on allergy risk.
While the results of the study are promising, it would be premature to suggest that parents buy pets or have more children, said Dr. Jonathan Bernstein, professor of medicine of University of Cincinnati College of Medicine and a co-author of an earlier report on the same topic.
Still, he said, the results provide further evidence that avoiding exposures may not be the best way to protect children against allergies.


J Allergy Clin Immunol 2011.