Background: Gastrointestinal (GI) infections are very common and are associated with numerous adverse consequences for the individual, healthcare sector and economy as a whole. Relatively little is known about whether the consequences of having a GI infection are experienced by all members of society equally or whether certain groups are disproportionately affected. Some evidence suggests those of lower socioeconomic status (SES) are more likely to present to healthcare services with GI infections. This may reflect greater need amongst more disadvantaged groups, either due to increased risk of infection or disease severity. This thesis endeavours to expand current understanding, by comparing inequalities in the incidence of infection amongst cases occurring in the community and those presenting to healthcare services. In addition, it explores the extent of inequalities in disease severity, sickness absence and hospitalisation outcomes due to GI infections. Methods: The framework of this thesis is based on theoretical knowledge of the mechanisms by which social stratification influences health outcomes. Three studies are presented. I begin by conducting a systematic literature review to examine inequalities in the risk of symptomatic GI infections in high income countries, using studies that have identified cases via healthcare records, laboratory notifications and population-based surveys. Narrative and meta-analytic methods are used to synthesise evidence and explore sources of statistical heterogeneity. I also analyse data collected in the UK-based Second Study of Infectious Intestinal Disease in the Community (IID2 study) to examine inequalities in self-reported symptom severity and sickness absence, amongst individuals with infectious intestinal disease (IID) aged > 5 years. Regression modeling is used to investigate inequalities in these outcomes, whilst exploring the impact of several covariates such as age, sex, ethnicity, urban/rural residency and recent foreign travel. Finally, I perform an ecological analysis using routinely collected Hospital Episode Statistics data, to evaluate inequalities in emergency hospital admissions for IID and the duration of these admissions, across England. Stratified analyses for children and adults are performed, and the effects of several neighbourhood-level characteristics on inequalities in admissions are assessed. Results: Firstly, the systematic literature review identified age as a statistically significant modifier of the association between SES and the risk of symptomatic GI infections. Children (aged < 18 years) of lower SES, but not adults, had a greater risk of infection compared to their more affluent counterparts. Lower SES was also associated with higher risk of infection amongst studies that identified cases via hospitals, most of which analysed children only. Secondly, analysis of the IID2 study revealed that IID cases aged >5 years, of lower SES, were more likely to experience severe symptoms and be absent from work or school. The association between SES and sickness absence was largely explained statistically by greater symptom severity amongst the more disadvantaged cases. Thirdly, in English neighbourhoods, increasing deprivation was associated with increasing emergency hospital admission rates and admission duration for IID, for both adults and children. The social gradient in admission rates was partly explained statistically by geographical factors and the higher prevalence of long-term health problems in the more deprived neighbourhoods. Conclusions: Important consequences of GI infections such as sickness absence, disease severity and emergency hospitalisation incur heavy burdens for individuals and societies. Evidence from this thesis suggests these adverse outcomes disproportionately affect socioeconomically disadvantaged groups. With this in mind, due consideration should be afforded to policies that address inequalities in the consequences of being ill with a GI infection, as well as current UK policies designed to reduce the risk of acquiring an infection.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:755553 |
| Date | January 2017 |
| Creators | Rose, Tanith Christine |
| Contributors | Taylor-Robinson, David ; Whitehead, Margaret ; Barr, Ben ; O'Brien, Sarah ; Hawker, Jeremy ; Violato, Mara |
| Publisher | University of Liverpool |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://livrepository.liverpool.ac.uk/3023009/ |
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