Dr Loftus and colleagues from Minnesota previously reported that the prevalence of Crohn's disease and ulcerative colitis in Olmsted County, Minnesota, had risen between 1940 and 1993.
The doctors sought to update the incidence and prevalence of these conditions in there region through 2000.
The team used the Rochester Epidemiology Project, which allows population-based studies of disease in county residents.
Crohn's disease and ulcerative colitis were defined by previously used criteria.
The team identified county residents newly diagnosed between 1990 and 2000 as incidence cases.
|Since 1991, the prevalence of Crohn's increased by 31%|
|Inflammatory Bowel Diseases|
Prevalence cases were identified as persons with these conditions alive and residing in the county in 2001.
All rates were adjusted to 2000 US Census figures for whites.
The researchers found that from 1990 to 2000 the adjusted annual incidence rates for ulcerative colitis were 9 cases per 100,000.
The annual incidence rates for Crohn's disease were 8 per 100,000.
The team of doctors noted that these rates were not significantly different from rates observed between 1970 and 1979.
The doctors found that in 2001, there were 220 residents with Crohn's disease, for an adjusted prevalence of 174 per 100,000.
In 2001, there were 269 residents with ulcerative colitis, for an adjusted prevalence of 214 per 100,000.
Dr Loftus' team concludes, “Although incidence rates of Crohn's disease and ulcerative colitis increased after 1940, they have remained stable over the past 30 years.”
“Since 1991 the prevalence of ulcerative colitis decreased by 7%, and the prevalence of Crohn's disease increased by 31%.”
“Extrapolating these figures to US Census data, there were about 1 million people with inflammatory bowel disease in the US in 2000.”