Children may have a lower risk of asthma as they grow older if they are raised in a household with dogs, cats, or other farm animals during their first year of life, according to a new study.
In the study – published November 2 in the journal JAMA Pediatrics – the researchers analysed the rate of asthma in 377,000 Swedish kids of preschool-age and 276,000 school-age kids, and their early exposure to farm animals and dogs.
Researchers found that school-age kids that had been exposed to dogs in their first year of life had a 13 percent lower risk of developing asthma at the age of six, compared with those who had not been exposed to dogs early in life.
The risk of school-age children – who had been exposed to farm animals during their first year of life – to develop asthma at the age of six was lowered by more than half (specifically 52 percent), compared with those who had not been exposed to farm animals before they turned one.
Tove Fall, an associate professor of Uppsala University in Sweden and author of the new study said that the reduction of asthma risk was not also seen in children whose parents already had asthma – when the children were exposed to dogs during their first year.
Preschool-age kids who had been exposed to farm animals during their first year of life had a 31 percent lower risk of developing asthma when they were one to five years old, as opposed to those who had not been exposed to farm animals during their first year.
The diagnoses of asthma were obtained by the researchers from the National Patient Register in Sweden. They also looked at whether the parents owned dog or worked with farm animals, during the child’s first year of life, and analysed data on prescribed asthma medication that had been sold at Swedish pharmacies. The study data was collected from 2007 to 2012.
Reduced risk of asthma “might be a combination of factors related to dog-owners’ attitudes, such as kids’ exposure to household dirt and pet dust, time spent outdoors or being physically active,” Fall said.
There is a hypothesis that may explain the link between early exposure to pets and lower risk of asthma and that is that some bacterial fragments – found in the air from an environment shared by both humans and animals – could actually lower that risk.
Dr. Purvi Parikh, an allergist and immunologist with Allergy & Asthma Network said that the new findings are related to the hygiene hypothesis. This hypothesis says that early exposure to bacteria is crucial for building a healthy immune system, and that it may lower the risk of developing allergies and asthma.
That being said, experts say that these recommendations are only for parents whose children are not already allergic to dust, animal fur, etc.
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