['Little is known about the exact etiology of primary sclerosing cholangitis (PSC); epidemiologic data are scarce. We performed a population-based epidemiologic study of PSC in Canterbury, New Zealand.', 'By using multiple case-finding methods, we searched public and private adult and pediatric outpatient clinics, hospital discharge summaries, and radiology and pathology reports to identify all cases of PSC in the region. Cases were included if PSC was identified by endoscopic retrograde cholangiography, magnetic resonance cholangiography, or liver biopsy analysis (n = 79).', 'The incidence of PSC in 2008 was 1.6 per 100,000 persons (95% confidence interval [CI], 0.5-2.7). The point prevalence on December 31, 2008, was 11.7 per 100,000 persons (95% CI, 8.7-14.8). The mean and median ages at diagnosis were 50 years (95% CI, 46-53 years) and 49 years (range, 17-80 years), respectively. Patients who had inflammatory bowel disease (IBD) presented with PSC earlier than those without IBD (P = .003), were more likely to develop serious malignant complications (P = .017), and were more likely to require liver transplantation or die (P = .03).'] Is inflammatory bowel disease associated with poor outcomes of patients with primary sclerosing cholangitis?