Epidemiology of primary biliary cirrhosis in Victoria, Australia: High prevalence in migrant populations

Background & Aims: The prevalence of primary biliary cirrhosis (PBC) reported in different countries varies widely, indicating that genetic or environmental factors may be important in the etiology of the disease. The aim of this study was to examine this issue further by determining the overall prevalence of PBC in one state in Australia and to examine the prevalence among different migrant groups within this population. Methods: Thorough case-finding methods were used to identify all cases of PBC in Victoria, Australia. Age-adjusted prevalence rates among different migrant groups were examined. Results: A total of 249 cases were identified, giving a prevalence of 51 cases per million. This is significantly higher than the rate documented in a 1991 Victorian study. Prevalence in the 3 largest migrant groups was greater than that of Victoria as a whole (141, 200, and 208 cases per million in British, Italian, and Greek migrants, respectively). In women older than 40 years, previous studies have documented a prevalence of 940 cases per million in women in the United Kingdom; however, the prevalence was 344 cases per million in British-born immigrants to Victoria and 160 cases per million in Australian-born women. Conclusions: The current prevalence of PBC in Victoria is higher than previously reported, but the age-adjusted prevalence in those born in Victoria remains significantly lower than in the United Kingdom and is less than in migrant communities. These findings suggest that Victorians may be relatively protected from developing the disease and add further weight to the suggestion that environmental factors may play a role in the etiology of PBC.