Short-Term Exposure to Ambient Particulate Matter Pollution and Surgical Outcomes

Introduction Particulate matter less than 2.5 mu m in diameter (PM2.5) can activate inflammatory cascades, cause oxidative damage, and induce cell death. Short-term exposures to PM2.5 have been associated with appendicitis and inflammatory bowel disease presentations, yet it is unclear if exposures may impact surgical recovery. Methods We conducted a retrospective cohort study of adult, colorectal surgery patients from 2006 to 2021. Institutional American College of Surgeons National Surgical Quality Improvement Program data were linked to Environmental Protection Agency PM2.5 concentrations on the day of admission stratified into low, moderately elevated, and high exposures. The environmental justice index chronic environmental burden and social vulnerability modules accounted for chronic stressors. The outcomes included length of stay (LOS), complications, and readmissions. After appropriate bivariate tests, multivariable regression models for the primary outcomes were constructed. Results 1038 patients were included with the majority experiencing low PM2.5 (53.4%, n = 554). Patients were similar in terms of demographic, clinical, and procedural characteristics across pollution groups, with a median age of 59.6, 53.5% female, 38.3% Black, and 74.5% American Society of Anesthesiologists class 3. The unadjusted outcomes did not differ significantly across groups; however, on adjusted models, higher PM2.5 groups had longer LOS: incident rate ratio 1.12 [95% CI 1.05-1.19] and incident rate ratio 1.37 [95% CI 1.16-1.62] for moderately elevated and high PM2.5, respectively (P < 0.001). Conclusions This study found a novel association between surgical outcomes and short-term ambient air pollution, with higher PM2.5 on the day of admission associated with longer LOS. Notably, this is also the first surgical study to use the environmental justice index to control for social and environmental determinants of health.