The incidence of inflammatory bowel diseases (IBD) in Asia has been on a perturbing rise over the last two decades. IBD encompasses Crohn’s disease and ulcerative colitis, and is classically a disease of the Western population.

"We suspected that IBD was becoming more common. We were seeing more cases of it in our centre; but we had no data for this trend," says a gastroenterologist in CUHK, Professor Siew Ng. Professor Ng sought to fill in this data gap by spearheading the Asia-Pacific Crohn’s and Colitis Epidemiology Study (ACCESS) – the largest Asian IBD study – that looked at the incidence of IBD in nine Asian countries and potential risk factors.

Top 3: Hong Kong, Macau and Guangzhou regions take poll with highest incidence of IBD

The ACCESS study revealed that three in 100,000 people in Hong Kong suffered from IBD. Previous data noted a 30-fold leap in IBD incidence in Hong Kong between 1985 and 2014. Interestingly, the top three areas were highly urbanised cities.

Staying in a rural location, pet contact during childhood and a longer duration of being breastfed appeared to reduce IBD risk. Risk factors identified in the ACCESS study included a sedentary lifestyle and possibly a diet more rich in processed food.

"A couple decades ago there was an emphasis on fresh food. Now people eat more processed convenience foods," says Professor Ng.

IBD, a multifactorial condition involving both environmental and genetic risk factors

Interestingly, ACCESS found that antibiotic use in childhood appeared to protect against IBD. This contributes a new facet to the growing evidence base on the effects of the environment and the development of immune-related conditions.

Other studies in the past have put forth air pollution as a risk factor for IBD. These environmental triggers are theorised to alter the gut microbiome which then produce a dysfunctional immune response leading to IBD.

However, IBD is ultimately a multifactorial condition. Over 200 genes have been identified to act as risk factors for IBD in European cohorts. It is interesting to note that only 3% of IBD patients in Asia were found to have a positive family history, compared to the 15% of Western patients. These genes may work in tandem with environmental triggers to ultimately result in IBD.

Multiple efforts underway to raise awareness on IBD in Hong Kong

IBD is a condition that severely impacts patients’ quality of life. The ACCESS study showed that three quarters of patients needed some form of surgery within a year of diagnosis. However, the progression patterns are similar to their Western counterparts.

In 2013, CUHK established a national Hong Kong IBD registry (the Nixon-TAM IBD Registry) in order to better gauge effect of the disease in the community. Furthermore, the Hong Kong IBD Society was formed in 2009 by group of healthcare professionals dedicated to research and education in IBD.

Although the rates of IBD in Asia are rising, they are still miniscule compared to the rates in the West. Canada holds the title of having the highest incidence of IBD in the world with 23.9 in 100,000 people being diagnosed with IBD every year. MIMS

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