Inflammatory bowel disease prevalence by age, gender, race, and geographic location in the U.S. military health care population.

Background: There is limited data examining the prevalence of inflammatory bowel disease (IBD) in a diverse North American population.

Methods: Using International Classification of Diseases, Ninth Revision codes, patients with Crohn's disease (CD) and ulcerative colitis (UC) seen within the military health care system (Tricare) from October 1, 2008 to September 30, 2009 were identified. This database comprised all active duty military, retirees, and dependents. The overall prevalence of IBD, UC, and CD was calculated, and the prevalence by age, gender, race, and geographic location.

Results: A total of 35,404 cases of IBD were identified in 10.2 million military health care beneficiaries establishing a prevalence of total IBD, UC, and CD of 348, 202, and 146 per 100,000, respectively. IBD was more prevalent in females compared with males (417 versus 284 per 100,000; relative risk, 1.53; 95% confidence interval, 1.50-1.57). There was an increased prevalence of IBD with each decade of life. IBD was more common in Caucasians (324 per 100,000) compared with blacks, Asians, Hispanics, and American Indians (239, 162, 147, and 224 per 100,000, respectively; relative risk, 1.60; 95% confidence interval, 1.53-1.67). There was no difference in prevalence when comparing Northern versus Southern states (339 versus 333 per 100,000, respectively, P = 0.114).

Conclusions: This large population study establishes a prevalence of IBD, UC, and CD (348, 202, and 146 per 100,000, respectively) in the military health care population. The prevalence of IBD, UC, and CD was higher in females and with increasing age, whereas IBD was most common in whites compared with other ethnicities in our patient population.