Crohn's Disease in Malaysia: Could Application of the Precautionary Principle Reduce Future Incidence?

Inflammatory bowel disease (IBD) comprises mainly Crohn's disease (CD) and Ulcerative Colitis (UC). The Western model suggests that environmental factors, immunological factors, the gut microbiome, and genetic disposition all contribute to the onset and sustained symptoms that define CD, although the pathogenesis of CD remains unresolved. Current studies propose that in individuals who are genetically susceptible, genetic factors linked to immune dysregulation, in combination with environmental exposure, can result in dysbiosis of the gut microbiome and intestinal barrier dysfunction, leading to immune dysregulation. In Malaysia, the incidence of IBD is rising with CD increasing disproportionally compared to UC, and the incidence of CD currently mirrors that of the United Kingdom in the 1930s, which now has one of the highest incidences worldwide. Given the suggested role of Mycobacterium avium subspecies paratuberculosis (MAP) in CD in Western countries, which is subject to some controversy, this review summarises for the first time the current evidence on genetic, environmental, and microbial factors that could contribute to the rise of Crohn's disease in Malaysia and proposes preventive approaches. We note the increasing reliance of Malaysia on imported cattle and milk products from areas of high Johne's Disease prevalence to meet increasing demand and changes in milk preferences in the Malaysian population, both key indicators for human-MAP exposure in the Western model. Therefore, should MAP be shown to be associated with CD in Malaysia, some preventative measures are suggested, such as screening imported and native beef and dairy cattle, dairy products and ultimately water, both recreational and potable.