PB0892 - Risk of venous thromboembolism is not increased with short-term PM2.5 air pollution even among at risk groups

Background: We formerly reported that acute exposure to PM2.5 was not associated with an increased odds of venous thromboembolism (‘VTE’—defined as deep vein thrombosis of the lower extremities and pulmonary embolism). However, we hypothesize that subgroups of patients with preexisting comorbidities exist that are at an increased risk of VTE when exposed to short-term PM2.5 air pollution.

Aims: Report the odds of VTE related to exposure to fine particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) with incremental increases in PM2.5 concentration of each 10 µg/m3 among at-risk patient subgroups. Risk was assessed overall, and during summer (June-October) and winter (November-March).

Methods: 25,560 VTE cases were identified using natural language processing interrogation of the electronic health record among non-hospitalized patients of Utah’s greater Salt Lake City area between 1 January 2008 and 31 March 2022. Patients were partitioned into at-risk subgroups (Table). The primary statistical analysis of VTE events and ambient PM2.5 were based on a time-stratified case-crossover design that matches exposures at the time of event with ≥1 period when the event did not occur to estimate the potential excess risk using conditional Poisson regression. PM2.5 exposure was estimated based on air monitoring at two stations with exposure attribution assigned to the station closest to the patient’s residence. VTE odds is reported in relation to increased PM2.5 exposure as a moving average (mAvg) of increased PM2.5 during the days –2 to 0 and days –6 to 0 preceding the VTE event.

Results: No significant associations were observed for PM2.5 exposure and the odds for VTE during a moving average of –2 to 0 days and –6 to 0 days preceding VTE diagnosis. When separated into summer and winter seasons similar results were observed (Table).

Conclusion(s): Short-term PM2.5 exposure was not associated with an increased odds for VTE even among at risk groups.