The changing epidemiology of inflammatory bowel disease across time and geography suggests that environmental factors play a major role in modifying disease expression.
Disease emergence in developing nations suggests that epidemiological evolution is related to westernisation of lifestyle and industrialization.
Dr Siew Ng from Hong Kong commented that the strongest environmental associations identified are cigarette smoking and appendectomy, although neither alone explains the variation in incidence of inflammatory bowel disease worldwide.
Urbanization of societies, associated with changes in diet, antibiotic use, hygiene status, microbial exposures and pollution have been implicated as potential environmental risk factors for inflammatory bowel disease.
|Country- and regionally based origin or risk factors may contribute to the pathogenesis of IBD|
The research team assessed that changes in socioeconomic status might occur differently in different geographical areas and populations and, consequently, it is important to consider the heterogeneity of risk factors applicable to the individual patient.
The research team found that environmental risk factors of individual, familial, community-based, country-based and regionally based origin may all contribute to the pathogenesis of inflammatory bowel disease.
Dr Ng and colleagues commented, "The geographical variation of inflammatory bowel disease provides clues for researchers to investigate possible environmental aetiological factors."
"The present review aims to provide an update of the literature exploring geographical variability in inflammatory bowel disease and to explore the environmental risk factors that may account for this variability."