July 31, 2023 – A groundbreaking study estimates nearly 1 in 100 Americans have inflammatory bowel disease and shines a light on the growing burden the disorder inflicts in the United States, where up to 56,000 new cases are diagnosed each year.
The research shows an estimated 2.4 million Americans have some form of IBD.
“The prevalence of IBD in the United States has been gradually increasing over the last decade, and thus the burden of caring for IBD is likely to increase as life expectancy increases,” said co-principal investigator Andrés Hurtado-Lorenzo, PhD, with the Crohn’s and Colitis Foundation.
Things like how much ultra-processed food you eat, pollution, and other things can impact your risk of IBD. Changes in environment and the fact that diagnostic tools are better are among the reasons the number of IBD cases is increasing, said, Manasi Agrawal, MD, a gastroenterologist at the Mount Sinai Hospital in New York City, who wasn’t involved in the study.
IBD is an umbrella term used to describe disorders that cause chronic inflammation of the digestive tract. Symptoms may include diarrhea, belly pain, nausea, fever, loss of appetite, fatigue, and, at times, rectal bleeding. The two most common forms of IBD are Crohn’s disease and ulcerative colitis. There are currently no cures.
The fragmented nature of the U.S. health care system makes it challenging to get an accurate estimate of how many people have IBD in the U.S.
The new study pooled data from commercial, Medicare, and Medicaid insurance plans to come up with an estimate of how many IBD cases there are in the U.S. and how fast those numbers are growing.
The study found that IBD is diagnosed in close to 1% of Americans, with 721 cases per 100,000 people. That’s nearly 1 in 100 people.
The start of IBD peaks in adults in their 30s and decreases in later years. Ulcerative colitis is slightly more common than Crohn’s disease in most age groups, except in children, in which this trend is reversed.
IBD happens the most in the Northeast and the least in the Western parts of the U.S.
The overall prevalence of IBD increased gradually from 2011 to 2020.
Historically, IBD was slightly more common in men. But the new data suggest it’s slightly more common in women and boys.
White people have a rate of IBD that is seven times higher than for Black Americans, six times higher than Hispanic people, and 21 times higher than Asian Americans.
The reasons for these ethnic disparities are “complex and multifactorial, and further research is needed to better understand the specific mechanisms underlying these disparities,” Hurtado-Lorenzo said.
Things that could add to this disparity include genetic and environmental factors, socioeconomic factors, health care disparities, differences in disease awareness and reporting, or under-diagnosis.
IBD is less common among children with Medicaid insurance, “which underscores the need for further investigation into the influence of social determinants of health on IBD care,” Hurtado-Lorenzo said.
Ashwin Ananthakrishnan, MD, MPH, a gastroenterologist with Massachusetts General Hospital and Harvard Medical School in Boston, who was not involved in the study, said the authors deserve praise for this “ambitious and important study.”
“Having an idea of how common IBD is and how it is likely to increase in prevalence is important for resource planning for organizations and health care systems,” he said.
This study provides “an initial step towards optimizing health care resources allocation and improving care of individuals with IBD,” Agrawal said.