The crucial period of early childhood

Breastfeeding, child nutrition and exposure to secondhand tobacco smoke at an early age may play a role in the onset of inflammatory bowel disease, according to a study conducted on Quebecers.

A research team led by Professor Marie-Claude Rousseau of the Institut national de la recherche scientifique (INRS) and Dr. Prévost Jantchou, researcher at the Center de recherche Azrieli du CHU Sainte-Justine and professor in the Department of Pediatrics at Université de Montréal has made several promising discoveries regarding risk factors for inflammatory bowel diseases (IBDs).

This study of 2,728 Quebecers provides new scientific insights into the etiology of Crohn’s disease, a chronic and incurable disease whose causes are not yet fully known. The findings are published in the journal Digestive and Liver Disease.

“Inflammatory bowel diseases affect nearly 1 in 100 Canadians and have a major impact on patients’ quality of life. With our work, we are providing concrete avenues for prevention, since to our knowledge, all of the factors studied can be modified by changing habits,” explains the study’s first author Canisius Fantodji, a doctoral student in epidemiology and immunology under the supervision of Professor Rousseau at INRS Armand-Frappier Santé Biotechnologie Research Center.

This is one of the few studies to look at exposure in early childhood, specifically 0 to 3 years of age. Yet early childhood is a crucial time for the establishment and diversification of the intestinal microbiota, the microbial ecosystem that plays a key role in intestinal health.

Breastfeeding and child nutrition: Major factors

The research team observed the effects of breastfeeding and diet in early childhood on the risk of developing inflammatory bowel disease later in life. These two factors directly influence the makeup of the microbiota.

In terms of diet, the research team made a novel finding: a slight increase in the risk of Crohn’s disease was observed when solid foods were introduced earlier (between 3 and 6 months of age) rather than later (past 6 months of age).

“Our work suggests that early introduction of solid foods in infancy may increase the risk of developing Crohn’s disease later in life. This discovery needs to be verified in other populations, but it opens the way for new avenues of research in this field,” emphasizes Professor Rousseau, a specialist in epidemiology and inflammatory and autoimmune diseases.

The research team also stresses the importance of exclusive breastfeeding whenever possible, as it tends to reduce the risk of developing Crohn’s disease. This observation aligns with current scientific knowledge and supports infant nutrition recommendations.

Dangers of secondhand smoke

The health risks associated with smoking are widely recognized by scientists and the general public. But for the first time, the research team has demonstrated that children exposed to secondhand tobacco smoke during their first three years of life have a 23% higher risk of developing Crohn’s disease compared to those who were not exposed. Only a small part of this increased risk can be explained by the subject’s own active smoking in adulthood, a previously unexplored aspect.

“Our work has brought to light several unique findings for the advancement of research, particularly concerning the harmful influence of secondhand smoke in early childhood in the development of inflammatory bowel diseases,” explains Fantodji.

“Until now, few studies have examined the links between secondhand exposure to tobacco smoke in early childhood and IBDs, and no study has been able to determine to what extent the effect of secondhand smoke exposure was explained by participants’ active smoking later in life,” points out Dr. Jantchou, clinician researcher and gastroenterologist at CHU Sainte-Justine and associate clinical professor at the Université de Montréal.

“This reinforces the importance of avoiding children’s exposure to tobacco smoke, not only for their general health, but also to limit their risk of developing chronic intestinal diseases in the future.”