By Dr. Becker
Not only do children who grow up with cats or dogs seem to have fewer allergies than kids in households without pets, but according to a new study, they also tend to get less respiratory and ear infections during their first year of life.
The study, published in the August issue of Pediatrics1, was led by Dr. Eija Bergroth, a pediatrician at Kuopio University Hospital in Finland. According to Dr. Bergroth:
"Children who had dog contacts at home were healthier and had less frequent ear infections and needed fewer courses of antibiotics than children who had no dog contacts."
Having a cat didn't seem to have as much impact on infection rates as dog ownership.
A Dog in the Home = Fewer Infections
The Finland study researchers tracked almost 400 children from before birth through their first year of life. Thirty-five percent lived in homes with dogs, while 24 percent had cats as pets. The researchers also accounted for contact with pets outside the home.
The infants who lived in homes with dogs had:
- 31 percent fewer respiratory tract illnesses/infections
- 44 percent fewer ear infections
- 29 percent fewer antibiotic prescriptions
The link between daily contact with dogs and less illness held true even when researchers accounted for other factors known to affect infection rates in babies (for example, breast feeding).
Having a cat also meant fewer infections, but the decrease wasn't nearly as significant as it was in the dog-owning population.
Study authors speculate that perhaps the dogs bring dirt or soil into the home and its presence strengthens the babies' immune systems. Or maybe the increased resistance to infection seen in the children has something to do with the dogs themselves.
Is Being Too Clean Unhealthy for Infants and Children?
Dr. Bergroth makes the point that many pregnant couples try to create a completely "anti-bacterial" environment in preparation for their baby's arrival. But study results indicate this may not be the best approach, because an extremely hygienic lifestyle doesn't allow the immune system to be challenged or to mature.
According to Dr. Roya Samuels, a pediatrician at Cohen Children's Medical Center in Hyde Park, NY, these study findings are novel in that they show a link between environments that challenge the immune system and reduced rates of infectious diseases:
"We associate exposure to dog and cat dander with lower allergy and asthma rates. But this paper is saying that, for reasons unknown, there is a protective mechanism at work lowering rates of infectious diseases," Samuels said.
The Finland study results build on a growing body of evidence in support of the hygiene hypothesis, which holds that the huge increase in allergic and other immune system disorders in the last century is due in part to our somewhat obsessive cleanliness standards.
It is thought that early exposure to bacteria and parasites prepares immature immune systems to fight dangerous infections. Further, this 'priming' of the immune system also helps it learn the difference between serious health hazards like a pneumonia infection, and harmless irritants like pet dander and pollen.
According to the hygiene hypothesis, when the immune system remains naïve from lack of exposure to real pathogens, it is more likely to mount attacks against benign environmental triggers.
Expectant Parents Don't Need to Get Rid of Their Pets
Dr. Bergroth hopes her study will help people understand they don't need to get rid of their pets if they're having children.
Future studies should investigate the actual mechanisms of protection involved when infants have contact with pets. The kids in the Finland study lived in rural or suburban areas, so the results may not apply in the same way to urban children, since city dwelling pets may not carry the same type of dirt into the home.