Incidence and mortality for respiratory cancer and traffic-related air pollution in São Paulo, Brazil
Introduction
Ambient air pollution has been well established as a risk factor in the development of lung cancer, with the International Agency for Research on Cancer (IARC) classifying ambient air pollution and its associated particulate matter as a Group 1 carcinogen (IARC, 2013). Further, diesel engine exhaust or emissions are also classified as Group 1 carcinogens based on sufficient evidence of increased risk of lung cancer (IARC, 2012).
The bulk of the evidence investigating air pollution and lung cancer risk has been derived from high-income countries, predominantly in North America and Europe (Beelen et al., 2008a, Hamra et al., 2014, Hystad et al., 2013, Olsson et al., 2011, Puett et al., 2014, Raaschou-Nielsen et al., 2016, Raaschou-Nielsen et al., 2013, Villeneuve et al., 2014, Yorifuji et al., 2016). With the exception of several studies conducted mainly in China (Li et al., 2018, Shao et al., 2019, Yue et al., 2017), there is a dearth of evidence from low and middle income countries (LMIC). Furthermore, a large number of recent studies only utilized mortality data and long-term exposure to conduct their risk analyses (Beelen et al., 2014, Bidoli et al., 2016, Carugno et al., 2016, Crouse et al., 2015, Fischer et al., 2015, Hansell et al., 2016, Lepeule et al., 2012, Yorifuji et al., 2013, Zhou et al., 2015) with relatively few studies using incidence data, with the notable exception of the ESCAPE study which analyzed air pollution and lung cancer incidence in European cohorts (Raaschou-Nielsen et al., 2013).
Previous studies have established that socioeconomic status (SES) can influence the exposure and effects of air pollution (Cesaroni et al., 2010, Deguen and Zmirou-Navier, 2010, Habermann et al., 2014, Havard et al., 2009, Pearce et al., 2006). In 2009, the Environmental Protection Agency (EPA) initiated activities to formalize and ensure that the development of regulations, in the context of environmental and health impacts, take into account environmental justice (Nweke et al., 2011). Thus, when evaluating the relationship between living near areas of high traffic density and exposure to air pollution, a socioeconomic analysis should be considered. According to Galobardes et al. (2007), socioeconomic measures on an area-level are specifically needed to investigate whether these aspects of the place where a person lives affects the person's health. Moreover, understanding the role of SES as an important factor of susceptibility to ambient air pollution is essential to the process of implementing air quality control programs (Samet and White, 2004).
To address the dearth of studies in LMICs and to evaluate the impact of a wider contrast in SES, we performed a study in São Paulo, where a broad contrast in SES exists, to quantify the association between incidence and mortality for respiratory cancers and traffic-related air pollution and its interaction with SES.
Section snippets
Study area
The municipality of São Paulo occupies an area of 1521.11 km2 and has a population of approximately 12 million, making it the largest and most populous city in Brazil (Fig. 1). It is the capital of the state of São Paulo, which is considered the main national industrial center, with a Gross Domestic Product (GDP) per capita of approximately 16 thousand dollars in 2014 (IBGE, 2017). It has a fleet of approximately 8.6 million vehicles (of which approximately 16% are diesel operated) which
Results
Of the incident cases, 21% were laryngeal malignancies (C32), 78% were bronchial and lung malignancies (C34) and less than 1% were tracheal malignancies (C33). Of the mortalities, 15% were related to laryngeal malignancies, 85% bronchial and lung malignancies, and less than 1% tracheal malignancies.
Fig. 2a and b show the traffic density and annual NO2 estimates for São Paulo respectively. In general, traffic density and NO2 were higher in the central regions than the peripheral regions and were
Discussion
This study found an increased rate of respiratory cancer incidence and mortality in association with an increase in traffic density and NO2 concentrations within São Paulo. Stratifying by categories of MHDI showed that the degree of this relationship was even more pronounced in the lowest, indicating that residents of these regions may suffer more from the effects of traffic-related air pollution.
Our results are generally consistent with previous work, although the larger IRRs observed here may
Conclusions
The results of this study show that traffic density and ambient NO2 concentrations were associated with an increased rate of incidence and death for respiratory cancers in São Paulo. This study also indicates that those with lower SES were more vulnerable to the development of respiratory cancers due to traffic pollution. While the reasons for this are not completely clear, it indicates an important at-risk group that warrants additional focus by policy makers and health providers.
Acknowledgments
We thank the National Council for Scientific and Technological Development (CNPq) – Process number 475362/2012-8, and the State of São Paulo Research Foundation (FAPESP) – FAPESP/PPP-SUS 2006/61616-5.
We also acknowledge the São Paulo Municipal Population-Based Cancer Registry and the São Paulo Municipal Health Department for the availability of the databases and the Institute for Risk Assessment Sciences – IRAS, Utrecht University, The Netherlands, as an important partner in this work.
Funding
This work was supported by the Brazilian Ministry of Education – Coordination for the Improvement of Higher Education Personnel (CAPES), Adeylson G. Ribeiro/PDSE Program/Process number 88881.134281/2016-01.
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