This news release from the University of Alberta reports that certain types of bacteria in the gut are more prevalent in people who have furry pets (in the study, 70 percent were dogs), and speculates that there may be an association between pets and the development of allergies and obesity.
Despite being short on details and explaining what the limitations are, the release is careful not to exaggerate the study findings. It says early on “don’t rush out and a adopt a furry pet just yet.”
The provocative theory whereby exposure to pet dogs in the womb or in the first three months of life can result in fewer allergies and even reduced incidence of obesity is far from proven. The release is clear about that. Still, we wish it had provided more details and numbers about what was studied and how many infant stool samples were taken.
If exposure to furry animals while in the womb or as a small infant were safe, harmless, relatively inexpensive and effectively helped children grow up to be free from allergies or obesity then this might be trumpeted as a true medical or social advance. As further research about the gut microbiome emerges so might understanding about how we can better avoid developing allergies, which are medically costly and extremely bothersome for a large portion of society.
These pet-friendly relationships are worth following up with more research. But the release was correct to be cautious with the study findings.
This is not relevant because we can assume that anyone who owns a dog is likely aware of the cost of housing, feeding and maintaining that animal and those amounts can be quite considerable.
We learn from the release: “The abundance of these two bacteria were increased twofold when there was a pet in the house,” and those effects take place “during pregnancy as well as during the first three months of the baby’s life.”
But we’re left wondering, twofold of what? And what kind of effects are related to a twofold increase in these two bacteria? The release doesn’t tell us.
There are no harms mentioned in the release release. Presumably there are some dangers of exposing babies in the womb and newborns to pet dogs and cats but we aren’t given any hint that they exist or what they are. One of the most common “harms” associated with furry pets is allergies, the very condition this study purports to lessen or prevent.
The causal relationship suggested in the headline is not warranted. At this stage of the research, a more accurate headline might be: “Pet exposure may or may not reduce allergy and obesity.”
The release would have been improved had it provided more discussion about the research. It noted the Canadian government has been running a study of children’s asthma and dog cohabitation for more than two decades.
But the release omits some of the basics about the research. For example, it mentions it analyzed infant stool samples but it doesn’t tell us how many samples nor from how many children. It also says there were “higher levels of two types of microbes associated with lower risks of allergic disease and obesity” in the samples. What is considered a “high” level? What’s considered average?
The published study tells us that the gut bacteria of 746 infants (a sub-sample from the Canadian Healthy Infant Longitudinal Development Study) were studied through fecal samples taken at 3.3 months. Researchers compared the bacteria found in the stool samples among those with or without pet exposure during pregnancy and 3 months after giving birth. They found that the infants whose families kept pets (a little more than half) had a higher presence of the Ruminococcus and Oscillospira bacteria which have been negatively associated with childhood allergies and obesity.
We do credit the release for at least acknowledging through a quote from the lead researcher that “It’s far too early to predict how this finding will play out in the future.”
There is no obvious disease mongering here, but the release might plant the suggestion that if readers don’t own a dog and don’t expose their infant to dog-related bacteria, then they may be exposing their children to a greater risk of some form of allergy or even obesity later on. It’s important for releases about association studies like this one was to describe the prevalence of a disease or condition so that people have a sense of what the normal rate of allergies might be in households with or without a dog.
The release tells us that the Canadian Institutes of Health Research and the Allergy, Genes and Environment Network (AllerGen NCE) funded the study.
This study is focused on describing the association between allergies and pets that were observed over a long-term study. But since the ultimate goal seems to be reducing allergies and asthma there are alternatives to exposing your baby to a dog to prevent them, such as incremental exposure and allergy screening tests. These alternatives were worth a brief mention.
It’s pretty clear that the availability of dogs in the US is a fact that doesn’t even need to be mentioned. According to the ASPCA, 44% of American households have a dog.
The release doesn’t claim a novel intervention but does say that this research builds on existing research and increases understanding of the pet-allergy connection. We’ll give them the benefit of the doubt on that.
There were some statements that bordered on unjustified terms, but nothing that rose to the level of sensationalism. For example, when the release referred to the “immunity-boosting exchange” that happens with various forms of childbirth we wondered: Where’s the evidence that these exposures ‘boost’ immunity? Is there such evidence?
And while the comment, “…Kozyrskyj doesn’t rule out the concept of a “dog in a pill” as a preventive tool for allergies and obesity,” is clever and catchy, it doesn’t have any basis in reality from this research which is still very much in the theory stage.