Background: The Department of Veterans Affairs (VA) is the largest healthcare system in the United States. The VA database was used to analyze patterns of hospitalization for inflammatory bowel disease (IBD) among US military veterans.
Methods: The study used the VA Patient Treatment File (PTF) between 1975 and 2006. Each hospital record extracted from the PTF included diagnosis, patient age, and ethnicity. Patient age was analyzed in three age groups: 0-44, 45-64, and 65+. Patient ethnicity was analyzed by two broad categories as white and nonwhite.
Results: Among veterans, Crohn's disease was more common than ulcerative colitis and both diseases were more common in whites than in nonwhites. During the past 30 years, the age distributions of both diseases have shifted towards older patients who have come to represent an increasingly larger fraction of patients with Crohn's disease, as well as ulcerative colitis. Hospitalization rates for inflammatory bowel disease among whites recently declined, while most rates among nonwhites continued to rise throughout the observation period.
Conclusion: The present study revealed a time-dependent shift towards older ages in the age distribution of IBD among hospitalized veterans. These changes, which have been observed similarly in other US statistics, may reflect a birth-cohort phenomenon underlying the long-term time trends of IBD.