PBC occurs in individuals of all ethnic origins and accounts for up to 2.0% of deaths from cirrhosis [15] . It primarily affects women with a peak incidence in the fifth decade of life, and it is uncommon in persons under 25 years of age. Incidence and prevalence vary strikingly in different geographic regions (as does the quality of epidemiological studies related to PBC), ranging from 0.7 to 49 and 6.7 to 402 per million, respectively [16] [17] [18] [19] [20] [21] [22] [23] . The highest incidence and prevalence rates are reported from the UK [16, 21] , Scandinavia [17] , Canada [18] , and the USA [19, 22] , all in the northern hemisphere, whereas the lowest was found in Australia [20] . There is no clear evidence to support or exclude the concept of "a polar-equatorial gradient," as it has been reported for other autoimmune conditions [24] .