Literature review: impacts of socioeconomic status on the risk of inflammatory bowel disease and its outcomes.

The relationship between socioeconomic status (SES) and inflammatory bowel disease (IBD) is controversial. To date, research has focused on effects on incidence and prevalence, disease management and clinical outcomes; however, conclusions remain uncertain. This review examines current evidence, identifies what remains to be understood and explores the practical implications this has for today. A structured literature search in Ovid, Medline, the Cochrane library, Google Scholar and clinicaltrials.gov was performed using defined key words, including all articles up until 5 October 2016 assessing SES as a primary or secondary outcome measure. Twenty-one studies were identified, investigating incidence and prevalence (n=13), disease outcomes (n=5) and mortality (n=3). Data linking SES with IBD incidence are conflicting, with studies citing both positive and negative trends. Patients with low SES, particularly those with Crohn's disease, show higher rates of hospitalization, service usage and IBD-associated mortality. On the basis of the available study data, it is difficult to relate SES with the risk of IBD. For Crohn's disease, in particular, the link between deprivation and increased hospitalization and mortality observed from world-wide studies is alarming. It seems most likely that the cause links to well-documented behavioural, materialistic, psychosocial and life-course models used to explain social class inequalities in other diseases.