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Long-term outdoor air pollution and cause-specific mortality in a pooled analysis of multiple Asian cohorts

Principal Investigator: 

Utrecht University, Netherlands

This is a large cohort study investigating long-term air pollution and cause-specific mortality in Asia, using pooled data from multiple cohorts in the Asia Cohort Consortium.

Funded under

Abstract for the 2019 HEI Annual Conference

Long Term Outdoor Air Pollution and Cause-Specific Mortality in a Pooled Analysis of Asian Cohorts

George S Downward1, Gerard Hoek1, Perry Hystad2, Eiko Sato3, Manami Inoue3, Sarah K. Abe3, Md. Shafiur Rahman3, Nat Rothman4, Qing Lan4, Zhu Tong5, Lutzen Portengen1, Roel CH Vermeulen1

1Utrecht University, Utrecht, the Netherlands; 2Oregon State University, Corvallis, OR, USA; 3National Cancer Center, Tokyo, Japan; 4National Cancer Institute, Bethesda, MD, USA; 5Peking University, Beijing, China

Background. Air pollution represents one of the most important risk factors for human health and global burden of disease (GBD). Annual GBD studies attribute approximately 4 million deaths per annum to ambient (outdoor) air pollution with much of the world – especially those in low-and-middle-income nations subject to levels of ambient air pollution in excess of World Health Organization (WHO) guidelines. The bulk of studies from which disease burdens and policy efforts have been derived are performed in North America and Europe. However, the largest global impacts of air pollution are estimated to occur in Asia, where air pollution levels are typically higher than North America and Europe. It is therefore uncertain whether the linear associations between air pollution and health often found in relatively low pollution areas extend to the higher pollution levels found in Asia. This knowledge gap is further compounded by cultural and socio-economic differences between (and within) Asian nations.

Objectives. The objectives of this project are to assess the association between long-term exposure to outdoor PM2.5 and NO2 and all-cause and cause-specific mortality in a pooled analysis of Asian cohorts. As a secondary objective, we aim to explore any observed heterogeneity in mortality risks in the context of cultural, social, economic, or infrastructural differences between cohorts and countries.

Study Design. Cohorts are being recruited from the Asia Cohort Consortium – a multicenter consortium representing about 500,000 participants. Levels of ambient air pollution will be assigned to the residential address(es) of study participants via the application of satellite-derived global models of air pollution (specifically PM2.5 and NO2). The association between ambient air pollution and natural cause and cause-specific mortality will be assessed by the generation of Cox proportional hazards models. Specific mortality outcomes which will be evaluated include lung cancer, cardiovascular disease, metabolic disease, and non-malignant lung disease. Data will be analyzed as a single “meta-cohort” in addition to cohort-specific analyses with subsequent meta-analysis. In addition to linear analysis, spline analysis will be employed to further evaluate the shape of the exposure-response relationship, especially at the higher levels of exposure. Together, these findings will provide important new insight into the burden of disease attributable to air pollution.


Poster by Vermeulen et al., 2019 HEI Annual Conference