Abstract
The incidence of inflammatory bowel disease (IBD) continues to rise throughout the world. About one quarter of all new diagnoses of this chronic, relapsing and remitting condition are made in childhood. The Paediatric Inflammatory Bowel Disease in New Zealand (PINZ) study is the first, prospective national study looking at the epidemiology and disease characteristics of IBD among the paediatric population in New Zealand.
In this thesis, the descriptive epidemiology of paediatric IBD throughout the world is explored. Beyond that, the setting up of the PINZ study is explained and its short and medium-term goals clearly defined.
Then, the incidence of paediatric IBD in the Canterbury region of New Zealand between 1996 and 2015 is methodically described. Annual incidence rates are given per 100 000 population and the trend of incidence over the 20-year period studied is statistically analysed. Disease characteristics are given in detail according to the Paris classification system for each case of Crohn’s disease, ulcerative colitis and inflammatory bowel disease unclassified (IBDU).
The final chapters of the thesis deal with the epidemiology of paediatric IBD in New Zealand in 2015. The point prevalence of paediatric IBD (and its sub-types) on 30 June 2015 and the prospectively-calculated national incidence of the same in 2015 are provided. Also, disease phenotypic information on each of the prevalent and incident cohorts is detailed.
The regional and national data obtained in this study are compared against the published epidemiological reports from other places in the world and future directions of the PINZ study are also discussed.