Review article: Epidemiological and animal evidence for the role of air pollution in intestinal diseases

Ambient air pollution is recognized as one of the leading causes of global burden of disease. Involvement of air pollution in respiratory and cardiovascular diseases was first recognized, and then cumulative data has indicated that the intestinal tract could be also damaged. To review and discuss the current epidemiological and animal data on the effects of air pollution on intestinal homeostasis. An extensive literature search was conducted using Google Scholar and Pubmed to gather relevant human and animal studies that have reported the effects of any air pollutant on the intestine. Exposure to several gaseous and particulate matter components of air pollution have been associated either positively or negatively with the onset of various intestinal diseases including appendicitis, gastroenteric disorders, irritable bowel syndrome, inflammatory bowel diseases, and peptic ulcers. Several atmospheric pollutants have been associated with modifications of gut microbiota in humans. Animal studies have showed that inhalation of atmospheric particulate matter can lead to modifications of gut microbiota, impairments of oxidative and inflammatory intestinal balances, and disruption of gut epithelial permeability. Overall, the literature appears to indicate that the gut is an underestimated target of adverse health effects induced by air pollution. It is therefore important to develop additional studies that aim to better understand the link between air pollutants and gastro-intestinal diseases. [Display omitted] •Epidemiological studies revealed associations between air pollutants and hospitalizations for several intestinal disorders.•Exposure to SO2, and to a lesser extent to NO2 and CO, could increase the risk of various intestinal diseases.•Exposure of mice to particulate matter causes disturbance of intestinal oxidative stress, permeability, and microbiota.•Numerous epidemiological and animal research gaps on the effects of air pollution in intestinal health remain to be filled.