Cats and dogs reduce allergy risk

Lower risk of allergies for children with early contact with dogs and cats

14/06/2011

The likelihood of allergy to animal hair is not increased by the contact of infants to dogs and cats, as previously thought, but rather lowered instead. Researchers from the Detroit-based Henry Ford Hospital, USA, come to this conclusion when evaluating data from a long-term study that began in the 1980s.

Overall, children's risk of allergy to pets is not increased but tends to be reduced, according to Ganesa Wegienka of Detroit's Henry Ford Hospital and colleagues in the latest issue of the journal „Clinical & Experimental Allergy“. Decisive for the risk of adolescents allergy, according to the US researchers, especially the first years of life. However, contact with pets has no negative impact on the risk of allergies at this point, but rather brings benefits, Wegienka and colleagues continue.

Keeping domestic animals without any negative effect on the risk of allergies
The previous assumption that children's risk of allergy would be increased by early contact with pets has not been confirmed in their current studies, said US researchers at the Detroit Henry Ford Hospital. Concern about the contact with animal hair is unfounded at this point, emphasized Ganesa Wegienka and colleagues. Because dealing with dogs and cats, the risk of allergy to adolescents is in no way negatively affected, so the result of the current study. Allergies and asthma do not occur more frequently in children who have been in contact with pets at an early stage than in animal-free households, the US researchers said in the current issue of the journal „Clinical & Experimental Allergy“. Based on the data of the Detroit Childhood Allergy Study, which has been recording the health and living conditions of the volunteers from the birth cohorts from 1987 to 1989 every year since the end of the 1980s, the researchers were able to determine whether there is a relationship between the position of pets and the subsequent risk of allergies.

Contact with cats reduces the risk of allergies by around 50 percent
The US researchers were able to use the available data to check if and how long the children were in contact with dogs or cats, which spent more than half of the time in the house. Finally, at the age of 18, 565 study participants submitted a blood sample to examine the antibodies against canine and cat allergens. The researchers found that adolescents in contact with pets produced as many or fewer antibodies as children without dogs or cats. An important finding of the current study is that adolescents who grow up with dogs and cats do not suffer from more animal allergies than children who have no contact with pets. In addition, the US researchers found that especially the first year of life has a decisive impact on the subsequent risk of allergy. For example, adolescents who have lived closely with cats in the first year are subject to an approximately 50 percent reduction in the risk of allergies to cat hair, the US researchers report.

First year of life crucial for the risk of allergy?
„We provide new evidence that first-year health experiences affect later-life health, said Ganesa Wegienka, a physician and biostatist at Henry Ford Hospital, Detroit. However, the positive effects on the risk of allergy can not be generalized, because the contact with dogs showed positive effects only on the boys. The boys had contact with dogs in the first year of life, this also reduced the risk of allergy by about 50 percent, but in the girls, the contact with the yapping four-legged friends had no effect. This is probably due to a different treatment of the girls and boys with the dogs, according to the US researchers.

Further studies on the early life phase planned
In a next step, the US researchers want to investigate the relationship between the contact with pets and the risk of allergy in more detail. According to Ganesa Wegienka, the focus is primarily on the early phase of life, but allow for the consideration of smaller time windows. For example, investigations on the first month or the first three months of life are conceivable, Wegienka and colleagues report. In the opinion of the US researchers, this is the phase of life in which the foundations for the subsequent immune defense are laid. The immune system, which has hardly developed directly after birth, is particularly vulnerable, according to the experts, and is only further developed through contact with the pathogens. Corresponding antibodies must first be formed and the defense reactions learned, so to speak. The handling of pets obviously has a beneficial effect. (Fp)

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