Psychological stress and inflammatory bowel disease: a follow-up study in parents who lost a child in Denmark.

Little is known about the association between psychological stress and the risk of inflammatory bowel disease (IBD). This study aimed to examine whether the death of a child is related to the development and exacerbation of IBD in bereaved parents. We undertook a follow-up study based on national registers. All 21,062 parents who lost a child (younger than 18 yr) from 1980 to 1996 in Denmark were included in the exposed cohort, and 293,745 parents matched on family structure were selected randomly from the general population to the unexposed cohort. Cox's proportional-hazards regression models were used to evaluate the relative risks (RRs) of first IBD hospitalization in the exposed parents, compared to the unexposed. Poisson regression models were fitted to estimate the frequency of IBD readmission between the exposed and the unexposed IBD parents. We used Wilcoxon tests to compare the mean duration of hospitalizations in the two groups of patients. There were 32 prevalent IBD patients at the study entry in the exposed cohort and 451 prevalent cases in the unexposed cases. We observed 301 incident cases of Crohn's disease (20 in the exposed, 281 in the unexposed) and 766 incident cases of ulcerative colitis (51 in the exposed, 715 in the unexposed). The RRs of first hospitalization for Crohn's disease and ulcerative colitis were 0.97 (95% CI = 0.62-1.53) and 1.01 (95% CI = 0.76-1.34), respectively. For incident or prevalent IBD patients, we did not observe any differences in the frequency or duration of hospitalization in the exposed and unexposed patients. Our findings do not support an association between psychological stress and the development of IBD in young-to-middle-aged adults.