Gastroenterology

Crohn’s disease can be transmitted to children… in the bathroom

In an article published in the May 2006 issue of the American Journal of Gastroenterology, epidemiologist Devendra Amre of the Université de Montréal reveals that a child’s risk of developing Crohn’s disease rises with the number of infections the child has had since early childhood.

A professor in the Department of Pediatrics, Faculty of Medicine, Amre analyzed 388 questionnaires that were sent out, half to mothers of children diagnosed with Crohn’s disease between 1995 and 2004, the other half sent to mothers whose children did not have the disease. The children averaged 12 years of age. The questionnaire covered all sorts of details regarding living conditions: availability of hot water, use of daycare, number of brothers and sisters in the household, whether bedrooms were shared, the number of shared towels hanging in the bathroom, and so on.

Comparing the two groups, Amre found a correlation between the appearance of Crohn’s and exposure to poor hygiene conditions. Households with a higher than average number of occupants, for example, as well as shared bathroom towels and owning a pet, are major risk factors. The article, co-authored by Philippe Lambrette, Liliane Law, Alfreda Krupoves, Virginie Chotard, and Florin Costea (of the UdeM) and four other researchers, concluded that infection-related exposures seem to enhance the risk of Crohn’s disease in children. The authors believe that the timing of these exposures during early childhood may be especially relevant in determining the risks of developing the disease.

The study marks a major milestone in our understanding of Crohn’s disease, contradicting the so-called “hygiene hypothesis” whereby repeated exposure to infections provides greater immune protection against the disease later in life. “Except for two or three studies, most of the research, including ours, does not support the hygiene hypothesis,” notes the researcher. However, the hygiene hypothesis could explain why certain children from densely populated countries, where sanitary conditions are execrable, have a very low Crohn’s infection rate.” Professor Amre explains that observing early exposure to infections can teach us a great deal about Crohn’s disease. The body, which is generally able to reject bacteria and micro-organisms that attack the intestines, seems to be unable to do so for people with Crohn’s disease.

And that can mean devastating consequences for children. Half of the patients have to undergo surgery, some even needing to have sections of their intestines removed. They suffer intense abdominal pain, chronic diarrhea, fever, and weight loss. Many children experience complications before they are even diagnosed. Amre believes that it is urgent to speed the pace of research on this disease, which is rising in the pediatric population. A generation ago, he estimates, only 25% of Crohn’s cases affected children. Today, that figure is nearly one in two.