June 20, 2011, 5:02 pm
Christoph Niemann
Really? The Claim: Pets Can Raise a Child’s Risk of Developing Allergies
By ANAHAD O'CONNORChristoph NiemannTHE FACTS
Many parents worry that keeping a dog or cat in the house may make a child more likely to develop pet allergies. But the scientific evidence suggests otherwise.
Instead, Fido and Whiskers seem to have the reverse effect. Most studies now show that children who are exposed to a pet during their first year have a lower likelihood of developing dog or cat allergies later on in life.
In the latest study, appearing this month in the journal Clinical & Experimental Allergy, researchers at the Henry Ford Hospital in Detroit followed 566 boys and girls from birth until age 18, regularly collecting data from the children’s families about exposure to indoor pets. At the end of the study, the researchers took blood samples and tested the subjects for their allergic sensitization to dogs and cats.
The children who had shared a home with a cat in their first year of life were about half as likely to be allergic to cats as those who had not. A decreased risk also was found in boys who lived with a dog as infants, though for some reason the effect was not as strong in girls.
The researchers also concluded that exposure at later ages did not make much of a difference — it was exposure in infancy that mattered. “The first year of life is the critical period during childhood when indoor exposure to dogs or cats influences sensitization to these animals,” the study’s authors concluded.
Another study published in The Journal of the American Medical Association in 2002 documented a similar pattern: Children exposed to two or more dogs or cats in the first year of life were less likely to develop allergies to dust mites, ragweed and dog and cat hair.
THE BOTTOM LINE
Research suggests that exposure to a dog or cat in the first year of life can reduce the risk of allergies to them.
Lifetime dog and cat exposure and dog- and cat-specific sensitization at age 18 years
- G. Wegienka1,
- C. C. Johnson1,
- S. Havstad1,
- D. R. Ownby2,
- C. Nicholas1,
- E. M. Zoratti3
Article first published online: 14 JUN 2011
DOI: 10.1111/j.1365-2222.2011.03747.x
© 2011 Blackwell Publishing Ltd
Additional Information(Show All)
Keywords:
- allergy;
- cat;
- dog
Summary
Background Prior research about whether keeping a dog or cat at home causes allergies to that pet has been limited to outcomes in early childhood.
Objective Evaluate the association between lifetime dog and cat exposure and allergic sensitization to the specific animal at 18 years of age.
Methods Participants enrolled in the Detroit Childhood Allergy Study birth cohort during 1987–1989 were contacted at the age 18 years. Sensitization to dog or cat was defined as animal-specific IgE
0.35 kU/L. Annual interview data from childhood and follow-up interviews at age 18 years were used to determine lifetime indoor dog and cat exposure (indoor was defined when the animal spent >50% of their time inside the house). Exposure was considered in various ways: first year, age groups and cumulative lifetime. Analyses were conducted separately for dogs and cats.
0.35 kU/L. Annual interview data from childhood and follow-up interviews at age 18 years were used to determine lifetime indoor dog and cat exposure (indoor was defined when the animal spent >50% of their time inside the house). Exposure was considered in various ways: first year, age groups and cumulative lifetime. Analyses were conducted separately for dogs and cats.Results Among males, those with an indoor dog during the first year of life had half the risk [relative risk (RR)=0.50, 95% confidence interval (CI) 0.27, 0.92] of being sensitized to dogs at age 18 compared with those who did not have an indoor dog in the first year. This was also true for males and females born via c-section (RR=0.33, 95% CI 0.07, 0.97). Overall, teens with an indoor cat in the first year of life had a decreased risk (RR=0.52, 95% CI 0.31, 0.90) of being sensitized to cats. Neither cumulative exposure nor exposure at any other particular age was associated with either outcome.
Conclusions and Clinical Relevance The first year of life is the critical period during childhood when indoor exposure to dogs or cats influences sensitization to these animals.
Cite this as: G. Wegienka, C. C. Johnson, S. Havstad, D. R. Ownby, C. Nicholas and E. M. Zoratti, Clinical & Experimental Allergy, 2011 (41) 979–986.
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