Incidence of cirrhosis in young birth cohorts in Canada from 1997 to 2016: a retrospective population-based study.

BACKGROUND: Recent data show that the prevalence of chronic liver disease and cirrhosis is increasing in adolescents and young adults in the USA. We aimed to describe the epidemiology of cirrhosis using an age-period-cohort approach to define birth-cohort effects on the incidence of cirrhosis in Ontario, Canada.

METHODS: We did a retrospective population-based cohort study in Ontario, Canada, using linked administrative health data from the databases of ICES, formerly the Institute for Clinical Evaluative Sciences. Patients aged at least 18 years with cirrhosis were identified by use of a validated case definition (defined as at least one inpatient or outpatient visit with a diagnosis of cirrhosis or oesophageal varices without bleeding). We calculated annual standardised incidence and prevalence in the general population. We used an age-period-cohort approach to assess the independent association between birth cohort and incidence of cirrhosis in men and women.

FINDINGS: Between Jan 1, 1997, and Dec 31, 2016, 165 979 individuals with cirrhosis were identified. The age-standardised incidence increased over the study (from 70·6 per 100 000 person-years in 1997 to 89·6 per 100 000 person-years in 2016) as did the prevalence (from 0·42% in 1997 to 0·84% in 2016). Using age-period-cohort modelling and the median birth year as the reference, the incidence of cirrhosis was higher in participants born in 1980 (incidence rate ratio 1·55, 95% CI 1·50-1·59, p<0·0001); and in participants born in 1990 (2·16, 95% CI 2·06-2·27, p<0·0001) compared with a person of the same age born in 1951. The increase in incidence of cirrhosis was greater in women than in men (eg, women born in 1990: 2·60, 95% CI 2·41-2·79; men born in 1990: 1·98, 1·85-2·12).

INTERPRETATION: The incidence of cirrhosis has increased over the past two decades, and more so in younger birth cohorts and in women. Future studies to define the cause and natural history of cirrhosis in these groups are essential to develop strategies that could reverse these trends for future generations.

FUNDING: Southeastern Ontario Academic Medical Association New Clinician Scientist Award; American Association for the Study of Liver Disease (AASLD) Foundation Clinical, Translational and Outcomes Research Award in Liver Disease (JAF).