Japan is seeing a rapid rise in cases of two chronic inflammatory bowel diseases, with estimated patient numbers climbing about 40% in just eight years, a government-backed study shows.
A health ministry team composed of researchers from Toho University, Kyorin University and Osaka Metropolitan University published their results this month in the Journal of Gastroenterology.
Their study estimated that as of 2023, there were 316,900 people in Japan with ulcerative colitis and 95,700 with Crohn’s disease. Compared with the last nationwide survey in 2015, which estimated there were about 220,000 ulcerative colitis patients and 71,000 patients with Crohn’s disease, the prevalence of such illnesses has risen roughly 1.4 times.
On a population basis, prevalence now stands at 254.8 cases of ulcerative colitis and 77.0 cases of Crohn’s per 100,000 people.
When compared with a similar survey in 1991, the estimated patient numbers for the diseases have jumped tenfold, according to the research.
Ulcerative colitis occurs in the large intestine, while Crohn's disease occurs in the mucous membranes of the digestive tract. Both are lifelong illnesses of unknown cause that inflame the digestive tract, triggering diarrhea, abdominal pain and other complications. There is no known cure.
Former Prime Minister Shinzo Abe resigned in 2007 and again in 2020 because of ulcerative colitis.
The two bowel diseases are classified as “designated intractable diseases” under a law that qualifies for government benefits for treatment. This category refers to incurable rare diseases with unclear pathological mechanisms requiring long-term care and that have a threshold of under 0.1% of the population, as well as one that can be diagnosed using objective criteria.
Researchers said the findings provide a more complete picture of the national disease burden by including mild cases and those not covered by government medical certificates. They urged continued monitoring to inform treatment, prevention and health-policy planning as prevalence rises.
With your current subscription plan you can comment on stories. However, before writing your first comment, please create a display name in the Profile section of your subscriber account page.