Young children growing up with a dog or in a large family may have some protection later in life from a common inflammatory bowel disease known as Crohn’s diseaseaccording to a study presented at Digestive Disease Week (DDW) 2022.
“Our study appears to add to others that have explored the ‘hygiene hypothesis,’ which suggests that lack of exposure to microbes early in life can lead to immune dysregulation of environmental microbes,” he explained. Dr. Williams Turpin, lead author of the study and associate researcher at Mount Sinai Hospital (United States) and the University of Toronto (Canada).
The researchers used an environmental questionnaire to collect information from nearly 4,300 first-degree relatives of people with Crohn’s disease enrolled in the Crohn’s and Colitis Canada Genetic, Environmental, and Microbial (CCC-GEM) project.
Using questionnaire responses and historical data collected at the time of recruitment, Dr. Turpin and his team analyzed various environmental factors, such as family size, presence of pet dogs or cats in the home, number of bathrooms at home, living on a farm, drinking unpasteurized milk and drinking well water. The analysis also included age at the time of exposure.
The study found that exposure to dogs, particularly between the ages of five and 15, was linked to healthy intestinal permeability and a balance between gut microbes and the body’s immune response, all of which may help protect against Crohn’s disease. Similar effects were seen with exposure to dogs in all age groups.
“We didn’t see the same results with cats, although we’re still trying to determine why,” says Turpin. It could potentially be due to dog owners going outside more often with their pets or living in areas with more green space, which has previously been shown to protect against Crohn’s.”
Another protective factor appeared to be living with three or more family members in the first year of life, which was associated with microbiome composition later in life. The gut microbiome is thought to play a role in several health conditions, including inflammatory bowel disease, colorectal cancer, diabetes, and high blood pressure.
However, he noted that environmental factors in early life were assessed using questionnaires, so care must be taken when interpreting these results due to possible recall bias at recruitment. The reasons why dog ownership and large families seem to protect against Crohn’s disease remain unclear.
Crohn’s disease is a type of inflammatory bowel disease that develops most often in young adults, people who smoke, and those with a close family member who has IBD. Symptoms include diarrhea, abdominal pain, and weight loss. Current treatments aim to prevent flare-ups of symptoms through diet modification, medication, and surgery.
*With information from Europa Press.