Background & Objectives: While exposure to fine particulate matter air pollution (PM2.5) is known to cause adverse health effects, its impact on postoperative outcomes in US adults remains understudied. Perioperative exposure to PM2.5 may induce inflammation that insidiously interacts with the systemic inflammatory response after surgery, leading to higher postoperative complications. Methods: We conducted a single center, retrospective cohort study using data from 64,313 surgical patients living along Utah's Wasatch Front and undergoing elective surgical procedures at a single academic medical center from 2016-2018. Patient addresses were geocoded and linked to daily Census-tract level PM2.5 estimates preoperatively. We hypothesized that elevated PM2.5 concentrations in the seven days prior to surgery would be associated with an increase in a bundle of major postoperative complications. A hierarchical Bayesians regression model was fit adjusting for age, sex, season, neighborhood disadvantage, and the Elixhauser index of comorbidities. Results: Postoperative complications increased in a dose-dependent manner with higher concentrations of PM2.5 exposure, with a relative increase of 7% in the odds of complications for every 10ug/m3 increase in the highest single-day 24-hr PM2.5 exposure during the 7 days prior to surgery. The association persisted after controlling for comorbidities and potential confounders; our inferences were robust to modeling choices and sensitivity analysis. Discussion & Conclusion: In this large Utah cohort, exposure to elevated PM2.5 concentrations in the week before surgery was associated with increased postoperative complications in a dose-dependent manner, suggesting a potential impact of air pollution on surgical outcomes. These findings merit replication in larger datasets to identify populations at risk and to define the interaction and impact of different pollutants. PM2.5 exposure is a potential perioperative risk factor and, given the unmitigated air pollution in urban areas, a global health concern.

Ben Goodrich and Jonah Gabry are both member-managers of GG Statistics, LLC.

This study was funded from an intramural University of Utah Wilkes Center for Climate Science and Policy seed grant [to JFP and NW] as well as partially supported by the National Institute of Health National Institute of Environmental Health Sciences and National Cancer Institute (NIH grant 5R01ES029528-05 [to MS], 5R37CA276365-02 [to NW]). Further funding was from the National Science Foundation (NSF grant 2051246 [BG] and 2153019[BG]). The funding sources were not involved in the study design, collection, analysis and interpretation of the data, in writing the report, or in the decision to submit the article for publication. The content is solely the responsibility of the authors and does not necessarily represent the official views of the National Institutes of Health, the National Science Foundation, or the University of Utah Wilkes Center for Climate Science and Policy.

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The Institutional Review Board of the University of Utah gave ethical approval of this work as Category 4, Exempt with IRB approval number 00142167.

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