The identification of true rises in disease incidence, in conjunction with other population trends, may provide useful insights into disease pathogenesis, especially with regard to environmental influences. By contrast, trends in disease prevalence are invaluable for organising current healthcare provision and also for planning future service design. For the general paediatrician, the rising incidence of inflammatory bowel disease (IBD) can be noted along with the general increase in incidence of complex immune diseases such as asthma and type 1 diabetes. Although IBD, comprising Crohn's disease (CD) and ulcerative colitis, can develop at any age, a significant proportion of patients are diagnosed in childhood. CD occurs anywhere in the gastrointestinal tract, notably with more extensive involvement at diagnosis in children when compared with adult-onset CD.1 Similarly, in ulcerative colitis, extensive or pancolonic involvement is more common in early-onset disease.1 Besides the acute medical complications faced in childhood, the burden of chronic IBD has further serious consequences for linear growth, education, future employment and psychosocial well-being.

Although there is currently a large body of evidence with regard to paediatric-onset IBD (PIBD) incidence worldwide, a significant proportion lacks data on trends over time.2 This issue of Archives of Disease in Childhood presents new and unique Irish PIBD data, evaluating incidence rates in the decade since the turn of the millennium. To place this research in context, it is important to consider historical data from the UK and Ireland. Within the UK, Scotland has a long history of PIBD …