Spatial Analysis and Determinants of Asthma Health and Health Services Use Outcomes in Ontario

Abstract

This thesis explores the spatial patterns and determinants of asthma prevalence and health services use (ICD-10 codes J45, J46) for the total population (all ages and both sexes combined) of the province of Ontario, Canada, between 2003 and 2013. Asthma is characterized by high health services use and reduced quality of life for asthma sufferers, representing a considerable burden on individuals, society and the health care system. While recent evidence suggests increasing asthma prevalence in Ontario, little research has been done to understand the identified spatial variability of this disease. Using population-based, ecological-level data and refined spatial analysis techniques, this research aims to explore the spatial patterns of asthma prevalence and health services use in Ontario, and examine the contribution of potential risk factors including air pollution, pollen, deprivation, physician supply and rurality. Results indicated considerable spatial variability in asthma outcomes across Ontario. Similar patterns were found between asthma prevalence and physician visits; clusters of high rates were generally found in southern urban/suburban areas, and clusters of low rates were mainly identified in most northern and southern rural areas. Conversely, clusters of high rates of ED visits and hospitalizations were found in most northern and southern rural areas, whereas clusters of low rates were found in south urban/suburban areas near Toronto. Findings from the spatial regression analysis indicated that while rurality was negatively associated with asthma prevalence and physician visits, it was positively associated with ED visits. Moreover, positive associations were also found between material deprivation and asthma prevalence and ED visits, and between NO2 and asthma physician visits. This research contributes to a better understanding of area characteristics that influence asthma disparities, which can help develop better, locally relevant public health strategies aimed at reducing the burden of asthma in Ontario. Further, it demonstrates the importance of using a population-based framework and spatial analysis approaches, which take into account the spatial nature of asthma morbidity and their determinants.