IBD Rates Rising Worldwide in Proportion with Urbanization

Disease prevalence has plateaued in the industrialized world, but is accelerating in developing nations.

More than 0.3% of people in industrialized nations have inflammatory bowel disease (IBD), according to a new systematic review. While this prevalence is plateauing, it is accelerating in developing nations, prompting scientists to recommend that health systems prepare infrastructure, resources and personnel to treat an increasing number of patients worldwide.

Siew Ng, PhD

“In the 21st century, urbanization is likely to play a role in the development of IBD. For example, in China, incidence of IBD appeared higher in urban than rural areas,” study author Siew Ng, PhD, told MD Magazine. Ng, a professor in the Department of Medicine and Therapeutics at The Chinese University of Hong Kong, pointed to westernized dietary patterns, improved hygiene status, increasing use of antibiotics, and increased exposure to pollution as just some of the “culprits of disease development” for IBD.

Along with Gilaad Kaplan, MD, professor in the Department of Medicine and Community Health Sciences at the University of Calgary, Ng and colleagues included 147 studies in the systematic review, and found that IBD incidence was highest in Europe and North America. In Europe, 505 per 100,000 people have ulcerative colitis in Norway, and 322 per 100,000 people have Crohn’s disease in Germany. In North America, 286 per 100,000 have ulcerative colitis in the US, and 319 per 100,000 have Crohn’s disease in Canada.

While overall incidence was high, on these 2 continents, 73% of studies on Crohn’s disease and 83% of studies on ulcerative colitis reported a stable or decreasing incidence of IBD around 0.3%.

On the contrary, incidence has been increasing in newly industrialized nations in Africa, Asia, and South America for nearly 30 years. In Brazil, annual percentage change (APC) for Crohn’s disease was +11% (95% CI 2.8-17.8) and +15% for ulcerative colitis (1.4-19.6). Similarly, in Taiwan, APC for Crohn’s disease was +4% (1.0-7.1) and +5% for ulcerative colitis (1.8-8.0).

Since their arrival around 2000, biologics have played a large part in helping curb disease incidence, Kaplan said, but they carry a burdensome price tag that will likely become problematic as incidence increases.

“Over the past 15 years, biologics have improved quality of life and kept many patients with IBD out of the hospital. However, the cost of biologics is high: tens of thousands of dollars every year. Our research shows that the number of patients with IBD will steadily climb. Thus, the cost of caring for patients with IBD who require biologics may put a strain on health care systems,” Kaplan said.

Gil Kaplan, MD

The authors urged clinicians to talk to their patients about methods for preventing onset of IBD, including smoking cessation, dietary changes, curbing unnecessary antibiotic use, encouragement of breastfeeding in high-risk individuals, and microbiota modulation.

“Studies are in progress to identify the association between IBD and the patient’s microbiota and dietary habits, as well as to identify bacterial transmission patterns from mothers with IBD to infants, which may help develop preventive measures against the disease early in life,” Ng said.

Data found in the systematic review highlight the need for future research into prevention of inflammatory bowel disease and innovations in health care systems to manage rising prevalence of IBD.

The study, Worldwide Incidence and Prevalence of Inflammatory Bowel Disease In the 21st Century: A Systematic Review of Population-Based Studies, was published October 16 in the Lancet.