Systematic Review on the Health Effects of Long-term Exposure to Traffic-Related Air Pollution

Abstract

The health effects of traffic-related air pollution (TRAP) continue to be of important public health interest. Following its well-cited 2010 critical review, the Health Effects Institute (HEI) is conducting a systematic review of the epidemiological literature on the health effects of long-term exposure to TRAP, with a new expert Panel. The Panel consists of 14 experts in epidemiology, exposure assessment and biostatistics, and is chaired by Francesco Forastiere (King’s College London) and Fred Lurmann (Sonoma Technology). Results are being combined quantitatively to evaluate the strength of evidence, where appropriate. The quantitative results of the review may be useful for future risk and health impact assessments of TRAP. The Panel is using a systematic approach to search the literature, assess study quality, summarize results, and reach conclusions about the body of evidence. To this end, a review protocol was developed and registered in Prospero. An extensive search was conducted of literature published between January 1980 and July 2019. Selected health outcomes include all-cause and cause-specific mortality, respiratory effects, cardiovascular effects, diabetes, and adverse birth outcomes. In addition, the Panel has developed an exposure framework to guide the selection and evaluation of epidemiological studies on TRAP. The review is now well underway, and preliminary results will be presented. After a broad search, the Panel has identified 1100 studies relevant for further screening; about 400 of which met the inclusion criteria and will be considered in the systematic review. Effect estimates were reported for all-cause mortality (40 papers), cardiovascular effects (70 papers), respiratory effects (180 papers), and birth outcomes (100 papers). The systematic review will undergo peer-review in 2020 and publication is aimed for 2021. The new review will be an authoritative update of HEI’s most-cited report for use by researchers and policymakers.