Countries in Africa, Asia, the Middle East and South America have seen a rise in incidence of inflammatory bowel disease as they have become increasingly industrialised and westernised, a new study has found.
The research, a collaboration between the University of Birmingham, the University of Calgary, Canada, and the Chinese University of Hong Kong, is the most definitive and comprehensive study of the global epidemiology of inflammatory bowel disease.
Future research should now focus on identifying environmental risk factors observed during the early stages of industrialization of society in order to highlight avenues to prevent the development of the disease. The data also highlights the need for research into prevention of inflammatory bowel disease and innovations in health-care systems to manage this complex and costly disease.
The study, published in The Lancet, was a systematic review of 147 world-wide observational studies reporting on the incidence or prevalence of two of the main conditions of inflammatory bowel disease – Crohn’s disease and ulcerative colitis – between 1990 and 2016.
Professor Subrata Ghosh, Director of the Institute of Translational Medicine, said: “Our study shows that, at the turn of the 21st century, inflammatory bowel disease has become a global disease with accelerating incidence in newly industrialised countries whose societies have become more westernised.
“We have shown an accelerating incidence in countries in Africa, Asia, the Middle East and South America that mirrors inflammatory bowel disease incidence in the Western world during the latter half of the 20th century.”
Dr Gilaad Kaplan, of the University of Calgary in Canada, said: “While our study demonstrates a paradigm shift whereby the incidence of inflammatory bowel disease in most Western countries has begun to stabilize and in some regions decrease, it is important to note that the prevalence of the disease is now 0.3% of the population in North America, Australia and most countries in Europe.
“The high prevalence of this disease in the Western world will challenge clinicians and health policy makers to provide quality and cost-efficient care to patients with this condition.”
Professor Siew Ng, of The Chinese University of Hong Kong, adds: “The rapid increase in incidence in many countries, especially in children, within one to two decades suggests strong environmental influence within a genetically susceptible population.
“The peak in the incidence of this disease has likely not transpired in newly industrialized countries. Consequently, these countries will need to prepare their clinical infrastructure and personnel to manage what is a complex and costly disease to treat.”
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- Ng et al (2017). ‘Worldwide incidence and prevalence of inflammatory bowel disease in the 21st century: a systematic review of population-based studies’. The Lancet. DOI: http://dx.doi.org/10.1016/S0140-6736(17)32448-0
- Crohn’s disease and ulcerative colitis are important and as yet unexplained diseases affecting the intestine with considerable morbidity, loss of productivity and a high societal cost. It often affects young people and children at the peak of their productive life. It affects about 300,000 people in United Kingdom and the disease is prevalent in Western industrialised countries including Australia and New Zealand.
- The researchers identified 147 studies that were eligible for final inclusion in the systematic review, including 119 studies of incidence and 69 studies of prevalence. The highest reported prevalence values were in Europe (ulcerative colitis 505 per 100 000 in Norway; Crohn's disease 322 per 100 000 in Germany) and North America (ulcerative colitis 286 per 100 000 in the USA; Crohn's disease 319 per 100 000 in Canada). The prevalence of inflammatory bowel disease exceeded 0·3% in North America, Oceania, and many countries in Europe. Overall, 16 (72·7%) of 22 studies on Crohn's disease and 15 (83·3%) of 18 studies on ulcerative colitis reported stable or decreasing incidence of inflammatory bowel disease in North America and Europe. Since 1990, incidence has been rising in newly industrialised countries in Africa, Asia, and South America, including Brazil for Crohn's disease +11·1% [95% CI 4·8–17·8] and APC for ulcerative colitis +14·9% [10·4–19·6]) and Taiwan (APC for Crohn's disease +4·0% [1·0–7·1] and APC for ulcerative colitis +4·8% [1·8–8·0]).