(Cox News Service) -- Children exposed to pets within the first year of life are much less likely to develop allergies, according to a new federal study that challenges what many doctors have believed about allergies.

According to the study, led by a Medical College of Georgia researcher and published in today's Journal of the American Medical Association, exposure to at least two dogs or cats early in life may reduce by 50 percent or more a child's risk of developing allergies in later childhood.

Incidence of allergy-related illness and asthma have increased significantly during the past 20 years.

The new study challenges the findings of research that led allergists to discourage exposure to animals in a child's first year of life. But Dennis Ownby, the study's lead investigator, said the new research does not support previous studies and should prompt scientists to "isolate and refine" effective new ways to prevent allergies.

"There were two problems with those studies," said Ownby, chief of the allergy and immunology department of MCG in Augusta. "The studies often involved relatively small numbers of children and the studies were retrospective; they examined children at around the age of 14 and asked `Did you have a dog in the house in early life."'

Ownby's Detroit-based study tracked 474 children born between 1987 and 1989 for seven years to see if those with pets were more likely to develop allergies. Sixteen percent of the children with no pets in the home developed a cat allergy compared with only 8 percent of those with two or more pets. At the same time, 9 percent of kids with no pets became allergic to dogs, compared with only 3 percent of children with two or more pets.

Researchers suggested early exposure to pets may change how a child's immune system responds to animals "in a way that helps protect against allergies."

Some experts suggest more research is needed to confirm the study before recommending a pet as a way to prevent allergies in children.

Dr. Kathleen Sheerin of the Atlanta Allergy and Asthma Clinic fears Ownby's study might be fogging the issue. "Obviously, this is the opposite of what we preach - avoid, avoid and avoid," Sheerin said. "The statistics are impressive but I need a few more studies."

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