One of the downsides of having a pet is the increased need to clean. Even the most fastidious pets leave their hair wherever they rest. But pediatrician and researcher Dr. James Gern and his colleagues suggest that there is something about having pets that can actually decrease the risk of childhood allergies and asthma, and it just might be related to that stuff they bring in and leave behind.
Do Pets Make Kids Healthier?
All across the world, the question of whether pets are good for a child’s health has been asked. There is not much consensus on the answer, unfortunately, however, there is consensus around the hygiene hypothesis—that a childhood devoid of germs entirely can lead to a less healthy child.
That’s not to say that all pet germs are good. Keeping a clean litter box for your cat and picking up after your dog are important. However, pet dander, pet-associated bacteria, or the amount of soil and particles kids come in contact with when they have pets may support the development of a healthier immune system.
On the other hand, a child’s health might have more to do with the lifestyle of families who choose to share their home with an animal. All of the research reported is self-selective. That is, the families who participated in the studies made their own decision about whether to have a pet and what kind. It could be that families who have pets are also more likely to spend time outside with their children or use fewer anti-bacterial products in the home.
To improve the reliability of the results, families would have to be assigned to have a pet or not in order to reduce this potential bias. This, of course, would not be a good idea for either the animals or the people involved.
Can Pets Really Prevent Asthma in Kids?
In recent years, researchers have begun to investigate particular relationships between genetic risk for allergies or asthma and the presence of a cat or dog in the house. This helps reduce some of the potential self-selection bias by studying only children with higher risk of developing allergies.
The meaning of a gene-environment interaction is this: genes are not necessarily active just because they are in your chromosomes. Some genes have to be turned on by another gene or by factors in the environment. Other genes can be switched off. This makes studying something as complex as childhood asthma even more complicated. But it also possibly explains why there is so little consensus between similar studies conducted in different regions of the globe.
The theory of a gene-environment relationship in asthma is supported by a recent study out of Denmark which said that children with the genetic risk factor for asthma were less likely to develop asthma in households with pets, especially cats. The study suggested that the association had to do with the amount of cat dander in the home—more dander meant less likelihood of asthma. The authors also found that high levels of cat dander are associated with increased risk of eczema.
However, the largest study conducted on this topic included over 22,000 children and found no relationship between asthma and allergies and pet ownership. If we consider this within the discussion of gene-environment interactions, it could be that this particular study included some children with risks for asthma exacerbated by pets, some whose symptoms were alleviated by pets, and others where pets had no effect on the children.
The Bottom Line
The take-home message is this: there are many factors that probably influence the development of allergies or asthma in children. Some may be straightforward (for example, air quality), while others have a more nuanced influence on immune health. Pets are great for emotional health and many aspects of physical health. Whether reduced risk of asthma and allergies are among the benefits of pet ownership are still unclear.
As a veterinarian, I am comfortable discussing how to care for furry family members. But before you make any decisions about the health of the humans in your family, consult your family physician.