A comprehensive assessment of environmental exposures among 1000 North American patients with primary sclerosing cholangitis, with and without inflammatory bowel disease

BACKGROUND: The relationships between primary sclerosing cholangitis (PSC) and the environment are largely unknown. AIM: To validate associations reported in previous studies and to identify novel environmental exposures among PSC patients. METHODS: We performed a multicenter, case-control analysis utilising self-administered questionnaires. Responses between cases (n = 1000) and controls (n = 663) were compared using multivariable logistic regression adjusted for age and gender. The model was further stratified based on inflammatory bowel disease (IBD) status (with IBD n = 741 without IBD n = 259). RESULTS: Smoking was associated with PSC only when IBD was present (OR, 0.5; 95% CI 0.4-0.7) but not among those PSC patients without IBD (OR, 0.9; 95% CI 0.7-1.2). Compared to controls, women with PSC (irrespective of the presence of IBD) were less likely to have received hormone replacement therapy (HRT; OR, 0.5; 95% CI 0.4-0.7) and were more likely to have recurrent urinary tract infections (OR, 1.6; 95% CI 1.2-2.3). PSC patients regardless of gender or IBD status were less likely to eat fish (OR, 0.4; 95% CI 0.3-0.6) and grilled/barbecued meat (OR, 0.8; 95% CI 0.7-0.9). In contrast, PSC patients with and without IBD were more likely to consume steak/burgers that were more well done (OR, 1.3; 95% CI 1.2-1.5). CONCLUSIONS: IBD (rather than PSC) is associated with smoking. Women with PSC are more likely to have recurrent urinary tract infections and less likely to receive HRT. Dietary intake and methods of food preparation differ in PSC patients when compared to controls