Particulate Matter and Temperature effects on respiratory mortality, considering socio-economic disparities, Sao Paulo - Brazil: a case-crossover analysis

摘要

Introduction: Socio-economic disparities inside large urban areas are a concern to the urban-planners as well to public health and environmental agencies. These disparities may interact with public health issues and environmental problems as air pollution and climate change, resulting a risk and effect harvesting. This study aims to investigating the interaction of environmental risk factors, such temperature and particulate matter, and socio-economic inequality in one of the world largest cities, Sao Paulo - Brazil. Methods: We applied time-stratified case-crossover analysis to 10 years of respiratory mortality daily counts in 35 districts with varrying social characteristics, also aggregated by 5 regions. Modeling of interaction terms and random effects were included to estimate the risk associated with PM10 and temperature based on district and region. Results: The total population results indicate that a 10μg/cm3 increase in PM10 concentration was associated with a higher respiratory mortality risk. The random effects model was not able to detect a significant effect by district, or region data due the stratification. The interaction terms provided an estimation of the effect modification by region. Conclusion: The risk associated with environmental factors may change by differential socio-economic characteristics, as illustrated in this study. The effect harvesting due these disparities highlight the need to draw up action plans by environmental and public health agents focusing on the more susceptible populations.