Examining the influence of socio-economic status, area level deprivation and exposure to air pollution on asthma in childhood in England

Abstract

The co-location of air pollution and socio-economic deprivation is increasingly well documented and studies have found that the socio-spatial distribution of health-related environmental characteristics, specifically air pollution, can be an important driver of geographical inequalities in health. The most deprived members of society face the highest exposures and the greatest risks due to a concept termed the triple jeopardy. Children face an increased susceptibility to air pollution exposure, and exposure can result in a range of health issues, such as asthma. Linking longitudinal data from the Millennium Cohort Study (MCS), air pollution data available from EMEP4UK, and area level deprivation data from the Index of Multiple Deprivation, this thesis aims to explore the relationship between air pollution exposure, and both individual and area level socio-economic status to understand how these exposures interact to impact respiratory health in children. Following data linkage, cross-sectional analysis, time series analysis and multilevel modelling are employed to examine the data. Multilevel modelling is used to appropriately attribute variations in spatial health outcomes to differences between places, differences between people within places and differences over time. The use of multilevel modelling is an innovative step in understanding the relationship between socio-economic factors, air pollution and health outcomes. Multilevel modelling found that 85% of the variation in asthma prevalence in children lies within MSOAs, whilst 14% of the variation was found to be over time. In comparison, 47% of the variation in wheezing was found to be due to differences over time. Two- and three-way interaction terms were included in the analysis to explore the impact of individual level socio-economic status, area level deprivation and air pollution exposure on asthma and wheezing prevalence in children, however no association was found. Moving forward, focussing interventions on improving both individual and area level socio-economic status, and implementing policies to lower pollution in the most deprived areas could help alleviate the health burden faced by the most deprived in society when exposed to air pollution