June 13, 2011
Children Who Live With Pets Less Likely To Develop Allergies
A new study suggests that children who live with dogs and cats are less likely to develop allergies to those animals later in life, but only if the pet is under the same roof while the child is still an infant.
The researchers found that, compared to babies born into cat-free homes, those who grew up with cats were roughly half as likely to be allergic to them as teenagers.
They found that growing up around a dog reduced the risk of dog allergies by about the same amount for boys, but not for girls.
Being exposed to pets anytime after the first year of life appeared to have no effect on allergy risks, which indicates that timing may be everything when it comes to trying to prevent allergies.
The researchers suspect that early exposure to pet allergens and pet-related bacteria strengthens the immune system, accustoms the body to allergens, and helps the child build up a natural immunity.
"Dirt is good," lead researcher Ganesa Wegienka, MS, PhD, of the Department of Public Health Sciences, Henry Ford Hospital, said in a statement. "Your immune system, if it's busy with exposures early on, stays away from the allergic immune profile."
This is not the first study to find that having a household pet may protect kids from allergies.
David Nash, M.D., clinical director of allergy and immunology at the Children's Hospital of Pittsburgh, said in a statement that previous studies have had mixed results so it is too early to recommend getting a dog or cat to ward off allergies in an infant.
"In the end, we'll probably find out that there are periods of opportunity when exposure to allergens, for some people, is going to have a protective effect," Dr. Nash, who was not involved with the new study, said in a statement. "But we're a long way from figuring out who it's protective for and when that optimal period is."
The team found that teenagers who lived with a cat during their first year of life had a 48 percent lower risk of cat allergy than their peers. Also, the teen boys who lived with a dog had a 50 percent lower risk of allergy.
The authors say infant girls may not develop the same immunity as boys because they may interact differently with dogs than infant boys.
The researchers collected information from 566 children and their parents about the kids' exposure to indoor pets and their history of allergies for the study.
The study is published the journal Clinical & Experimental Allergy.
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