January 4, 2017 — In 1932, New York gastroenterologist Burrill Crohn described an unusual disease in 14 adults. The patients had bouts of abdominal pain, bloody diarrhea, and lesions and scars on the bowel wall. Doctors in other parts of North America and Europe were seeing it in their patients, too. They called the rare condition Crohn’s disease. After World War II, the number of new people getting inflammatory bowel disease (Crohn’s disease and a related condition called ulcerative colitis) skyrocketed across the West in countries such as the U.S., Canada and the UK. In the last three decades, IBD has begun to crop up in newly industrialized parts of the world like Hong Kong and China’s big cities.
Other conditions, such as type 1 diabetes, rheumatoid arthritis and multiple sclerosis, are becoming more common, too. These diseases affect different parts of the body, but they all have one thing in common — they’re marked by a malfunctioning immune system. Doctors call these illnesses immune-mediated diseases. (Autoimmune diseases are a subset of these, though the terms often are used interchangeably in the popular press.) More than 100 conditions fall into this category. For the most part, these diseases are chronic and cause long-lasting disability. Most were rare or completely unknown until recently, but now constitute what some experts call an epidemic. In Hong Kong for instance, the incidence of IBD spiked 30-fold between 1985 and 2014.