Early life contact with dogs helps to prevent asthma, concludes a new study that adds to the growing body of research that pet ownership can confer health benefits to humans.
Prior research had already found a link between reduced risk of asthma and dog ownership, so the new study, published in the journal JAMA Pediatrics, strengthens those findings.
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"Earlier studies have shown that growing up on a farm reduces a child's risk of asthma to about half," project leader Tove Fall of Uppsala University said in a press release. "We wanted to see if this relationship also was true also for children growing up with dogs in their homes."
The extensive study looked at more than one million children, with data collected on early life exposure to dogs and incidence of asthma. Individuals who grew up with dogs were found to have about 15 percent less asthma than children without dogs.
While 15 percent is not a huge number, it still demonstrates that dogs can be beneficial to human health, and it certainly negates any concern that dog ownership might somehow induce asthma in very young children.
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The researchers attribute the benefits to the so-called "farming effect." It's suspected that exposure to dogs can reshape the community of microbes that live in an individual's gut. This microbe community is known as the gastrointestinal microbiome.
With the body better primed to tolerate things like dog fur and dander, immune system reactivity to such common allergens appears to reduce.
Asthma can be tied to genetics as well, but the study accounted for this and other important possible health factors.
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As Fall explained, "Because we had access to such a large and detailed data set, we could account for confounding factors such as asthma in parents, area of residence and socioeconomic status."
It's also important to remember that the exposure to dogs must be constant and happen starting very early in an individual's life. Once the person develops asthma or a particular allergy, it's best that they try to avoid the triggers.
"We know that children with established allergy to cats or dogs should avoid them, but our results also indicate that children who grow up with dogs have reduced risks of asthma later in life," senior author Catarina Almqvist Malmros of the Karolinska Institutet in Stockholm explained.
The asthma perk adds to an already long list of other mental and physical health benefits associated with dog ownership. According to the University of Pennsylvania School of Veterinary Medicine, these benefits include increased physical activity, decreased blood pressure, improved survival following cardiac surgery, decreased anxiety and social isolation, and improved self-esteem and social support.