Integrating time activity in environmental exposure assessment: Implications for epidemiological studies

Abstract

The built environment is associated with various environmental exposures such as air pollution, noise, and fast-food outlets. In this thesis, we use environmental data at fine resolution and we integrate time-activity information in exposure assessment methodologies to study the relations between environmental factors and health, and to investigate the distribution of exposures among groups with different socio-economic status (SES). To test the exposure methodologies and examine the associations between environmental exposures and health we applying them in existing cohorts. The thesis is divided into three parts. In the first part, the associations between air pollution and health in children are examined by using exposure assessment methodologies which incorporate time-activity patterns. We showed that air pollution exposures are consistently associated with decreased carotid artery distensibility in children 5 years old. Furthermore, by comparing the associations between air pollution and lung function, by using four exposure assessment methodologies, we concluded that the annual average exposure to air pollution for 8-year-old children in the Netherlands is sufficiently captured by the residential exposures. In the second part of the thesis we studied the associations between fast-food environment and cardio-metabolic diseases. Individual level analysis showed that the presence of fast-food outlets near the residential address showed significant associations with the presence of both cardiovascular diseases (CVD) and diabetes. The strength of the associations varied among the network buffer-sizes used in the exposure assessment. The smaller buffer (500m) showed the strongest associations between fast-food outlet environment and CVD in the urban environment. The presence indicator (exposed or not to fast-food outlets) in urban areas showed the most consistent associations among the buffer sizes. In the third part, disparities in environmental exposures and exposure response among social groups in the Netherlands were investigated. We showed that unfavourable environmental exposures were higher for neighbourhoods in the highest and lowest quartiles of SES score and individual income compared to the two mid-quartiles. Neighbourhoods with a higher proportion of impoverished residents are characterised by higher levels of air pollution, noise and green space.