Occupational mortality from inflammatory bowel disease in the United States 1991–1996

Abstract

OBJECTIVE: The occupational distribution of inflammatory bowel disease (IBD) may help to shed light on its yet unknown etiology. The U.S. vital statistics offer the opportunity to study cause of death by occupation and industry. METHODS: The numbers of deaths from Crohn’s disease and ulcerative colitis were retrieved from the computerized 1991–1996 data files of the National Center for Health Statistics. Deaths were grouped by gender, ethnicity, disease type, occupation, and industry. Mortality by occupation and industry were expressed as proportional mortality ratio (PMR), adjusted for gender and ethnicity. RESULTS: Between 1991 and 1996, 2399 subjects died from Crohn’s disease and 2419 subjects died from ulcerative colitis. Significant correlations were found between the PMR values of ulcerative colitis and Crohn’s disease regarding their distribution by occupation, r = 0.36 and p < 0.05, as well as by industry, r = 0.37, p < 0.01. IBD mortality by occupation was significantly reduced among farmers (PMR: 70, 95% confidence interval [CI]: 42–97), mining machine operators (31, 95% CI: 0–74), and laborers (71, 95% CI: 45–98). A nonsignificant increase was found among sales persons (117, 95% CI: 95–139) and secretaries (122, 95% CI: 83–161). IBD mortality by industry was significantly reduced in agricultural production of livestock (39, 95% CI: 1–78), mining (46, 95% CI: 9–83), grocery stores (55, 95% CI: 17–94), and work in private households (64, 95% CI: 30–97). A nonsignificant increase was found in food production (128, 95% CI: 74–182), investment and insurance business (137, 95% CI: 77–198), and administration (122, 95% CI: 81–163). CONCLUSIONS: IBD mortality is low in occupations associated with manual work and farming and relatively high in sedentary occupations associated with indoor work. Crohn’s disease and ulcerative colitis show a similar distribution.