9 This

is the first and largest population-based epidemiological study of AIH which has used the standardized scoring system to classify patients. Access to all Gastroenterologists and Hepatologists in the region allowed identification of cases under their care and a recording of demographic, clinical, laboratory and liver biopsy results. The population studied was predominantly of European descent, mainly from the UK and Ireland, with a smaller proportion being of Maori, Asian or Pacific Islander origin. The findings demonstrated a relatively high incidence (2.0/100 000) and prevalence (24.5/100 000) of autoimmune hepatitis in this region. The age-standardized GSI-IX mouse incidence and prevalence were 1.7/100 000 and 18.9/100 000, respectively. Consistent with earlier demographic studies, AIH was significantly more prevalent in women and in the Caucasian population. However the peak age at presentation was in the sixth decade with a median and

mean age at presentation of 54 and 50, respectively. This contrasts with older studies, in what was then called autoimmune chronic active hepatitis, which indicated that this syndrome was a disease of teenage and young female adults.5 Later studies suggested a bimodal distribution of the age at presentation with peaks in the peripubertal and 40–50 age brackets.10 More recent studies, from the UK, Europe, Asia and Australia1,7,11 have revealed a unimodal age at presentation; with a peak in the sixth decade of life and this is certainly consistent this website with the results reported by Ngu et al.9 check details Multiple factors could have contributed to this

apparent change in the age of patients presenting with AIH. The introduction of a more robust scoring system to identify patients with AIH may have detected disease in older patient groups that had not been captured in earlier epidemiological studies because of mild disease or atypical clinical features and presentation. Examples include patients with variant, overlap or mixed forms of AIH, or those classified by the IAHG scoring system as probable AIH. Such patients were included in the study reported by Ngu et al. as well as other more recent epidemiological studies. Alternatively, the change could reflect an increasing incidence of AIH among the older population, and/or a decreasing incidence among the young. The pathogenesis of AIH remains unknown. However, the most popular concept is that an environmental trigger initiates an immunologically mediated inflammatory reaction directed against liver antigens in a genetically predisposed host. In turn, this results in liver cell necrosis and hepatic fibrosis and can progress to cirrhosis and liver failure.1 A genetic susceptibility to AIH has been well established over many years, largely based on studies linking HLA genes to a predisposition to AIH Type 1.12 AIH is associated with the HLA–DR3 serotype, particularly among young female Caucasians with the early onset severe form of AIH.