Gastroenterology

Gastroenterology

Volume 114, Issue 6, June 1998, Pages 1161-1168
Gastroenterology

Alimentary Tract
Crohn's disease in Olmsted County, Minnesota, 1940–1993: Incidence, prevalence, and survival,☆☆

Presented in part at the annual meeting of the American Gastroenterological Association, May 11–14, 1997, in Washington, D.C., and published in abstract form (Gastroenterology 1997;112:A1027).
https://doi.org/10.1016/S0016-5085(98)70421-4Get rights and content

Abstract

Background & Aims: Many centers worldwide have reported an increased incidence of Crohn's disease, but population-based data in North America are sparse. We studied the incidence and prevalence of Crohn's disease in Olmsted County, Minnesota, and examined temporal trends in incidence and survival. Methods: Residents diagnosed with Crohn's disease between 1970 and 1993 were incidence cases, and residents with Crohn's disease who were alive on January 1, 1991, were prevalence cases. Cases from previous studies were reconfirmed. Rates were adjusted using 1990 U.S. Census figures for whites. Incidence trends were evaluated with a Poisson regression model. Survival from diagnosis was compared with that expected for U.S. north-central whites. Results: Between 1940 and 1993, 225 incidence cases were identified, for an adjusted incidence rate of 5.8 per 100,000 person-years. On January 1, 1991, there were 145 residents with Crohn's disease, an adjusted prevalence rate of 133 per 100,000, 46% higher than that seen in 1980. Incidence rates before 1964 were significantly lower than those of 1989–1993. Observed survival was less than expected (P = 0.007). Conclusions: The incidence of Crohn's disease has stabilized since the 1970s at a rate higher than that seen previously. Prevalence has increased by 46% since 1980. Overall survival is slightly decreased.

GASTROENTEROLOGY 1998;114:1161-1168

Section snippets

Setting

Olmsted County, situated in southeastern Minnesota, comprised approximately 106,000 people in the 1990 U.S. Census. The county's urban center, Rochester, comprised approximately 71,000 people in 1990. The remainder of the county is rural. In 1990, 96% of the population was white. Although 25% of the residents are employed in health care services (vs. 8% nationwide) and the level of education is higher (30% have completed college vs. 21% nationwide), the residents of Olmsted County are

Demographic characteristics

Between 1940 and 1993, a new diagnosis of Crohn's disease was made in 225 Olmsted County residents. One hundred twenty-two patients were female (54%), resulting in a female to male ratio of 1.2:1. The mean age at diagnosis was 33.4 years. The median age at diagnosis was 29.5 years (range, 4.2–83.8 years). The diagnosis was most commonly made in the third and fourth decades of life (Figure 1).

. Crude incidence of Crohn's disease in Olmsted County, 1940–1993, by age at diagnosis.

There was no

Discussion

The incidence of Crohn's disease in Olmsted County, Minnesota, increased dramatically during the 1960s and early 1970s, and has since stabilized at a rate of roughly 7 cases per 100,000 person-years. The prevalence rate increased by 46% between 1980 and 1991. The “classic” age distribution of onset of Crohn's disease, with the majority of cases diagnosed in the third and fourth decades of life, did not become evident in our county until the mid-1960s. The overall survival of this inception

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Supported by Schering–Plough, by National Institute of Arthritis and Musculoskeletal and Skin Diseases grant AR30582, and by the Mayo Foundation for Medical Education and Research.

☆☆

Address requests for reprints to: Edward V. Loftus, Jr., M.D., Division of Gastroenterology, Mayo Clinic, 200 First Street, Southwest, Rochester, Minnesota 55905. e-mail: [email protected]; fax: (507) 266-0335.

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