title: Low incidence and prevalence of primary biliary cirrhosis in Canterbury, New Zealand: a population-based study.
abstract: OBJECTIVE
  Epidemiological data on primary biliary cirrhosis (PBC) in the Southern Hemisphere is scarce. Our aim was to perform a population-based epidemiological study of PBC in Canterbury, New Zealand.
  
  
  METHODS
  Multiple case-finding methods were employed. All public and private, adult and pediatric outpatient clinics, hospital discharge summaries, and laboratory and pathology reports were searched to identify all cases in the region. Cases were included if at least two of the following criteria were fulfilled: (1) positive anti-mitochondrial antibodies, (2) elevated alkaline phosphatase for greater than 6 months, and (3) compatible liver histology.
  
  
  RESULTS
  A total of 71 cases of PBC were included. The incidence in 2008 was 0.8 (95% confidence interval (CI) 0.1-1.6) per 100,000. The point prevalence on December 31, 2008 was 9.9 (95% CI 7.1-12.7) per 100,000. Male to female ratio was 1:11. At presentation, 45% were asymptomatic. Age at diagnosis peaked at the seventh decade with mean age at diagnosis of 61 (95% CI 58-64).
  
  
  CONCLUSIONS
  This is the first population-based epidemiological study of PBC conducted in New Zealand and only the second in the Southern Hemisphere. The incidence and prevalence are lower than the Northern Hemisphere, even though the majority of our population has shared genetic background with some of these countries. Our study has provided further support to the hypothesis that there may be a protective effect or lack of a risk factor for PBC in New Zealand.
authors.affiliation: Department of Gastroenterology, Christchurch Hospital, Private bag 4710, Christchurch, Canterbury, New Zealand.|University of Otago, Christchurch, Canterbury, New Zealand.
authors.forename: Jing Hieng
authors.initials: JH
authors.lastname: Ngu
authors.affiliation: Department of Gastroenterology, Christchurch Hospital, Private bag 4710, Christchurch, Canterbury, New Zealand.|University of Otago, Christchurch, Canterbury, New Zealand.
authors.forename: Richard Blair
authors.initials: RB
authors.lastname: Gearry
authors.affiliation: University of Otago, Christchurch, Canterbury, New Zealand.
authors.forename: Andrew Jeffrey
authors.initials: AJ
authors.lastname: Wright
authors.affiliation: Department of Gastroenterology, Christchurch Hospital, Private bag 4710, Christchurch, Canterbury, New Zealand. Catherine.stedman@cdhb.govt.nz.|University of Otago, Christchurch, Canterbury, New Zealand. Catherine.stedman@cdhb.govt.nz.
authors.forename: Catherine Ann Malcolm
authors.initials: CA
authors.lastname: Stedman
keywords: Epidemiology; Incidence; Prevalence; Primary biliary cirrhosis