Influence of atmospheric conditions and air pollution on pulmonary embolism incidence and severity: findings from a retrospective cohort study

Introduction: Pulmonary embolism (PE) is a complex condition influenced by both genetic and acquired factors. While traditional risk factors are well-documented, emerging research highlights the role of environmental factors, including meteorological conditions and air pollution, on the incidence of PE. The growing impacts of climate change, particularly through rising temperatures and increasing air pollution, may exacerbate these environmental risks. However, existing studies provide inconsistent findings on this relationship. Our study aimed to assess the associations between air temperature, barometric pressure, particulate matter (PM), and the incidence and severity of PE at a major tertiary care center.

Method: We conducted a single-center cohort study of all PE cases at the Vienna General Hospital (Austria) during a four-year period. Poisson regression was used to analyze the relationship between PM_2.5, PM₁₀, air temperature, and barometric pressure on PE incidence. Ordinal logistic regression assessed the association between these environmental factors and PE severity, classified according to European Society of Cardiology (ESC) guidelines. Daily average concentrations of PM_2.5, PM₁₀, barometric pressure, and air temperature were calculated by using a 10-day moving average (lag 0-9 days) for each variable prior to PE diagnosis.

Results: Data of 969 PE patients (median (IQR) age: 64 (50-75) years; 50.3% women) were analyzed. Higher average levels of barometric pressure, PM_2.5, and PM₁₀ (lag 0-9 days) were significantly associated with an increased weekly incidence of PE (see [Fig. 1]). The relationship between air temperature and PE incidence followed a reverse U-shaped pattern (p=0.052). Specifically, for each 1 hectopascal (hPa) increase in barometric pressure, weekly PE incidence increased by 1.8% (95% CI: 0.4%; 3.1%). A 1 µg/m³ increase in PM_2.5 was linked to a 0.8% (95% CI: 0.0%; 1.6%) increase in PE cases, while a 1 µg/m³ increase in PM₁₀ was associated with a 0.9% (95% CI: 0.1%; 1.6%) rise in PE cases. These associations were primarily driven by the subgroups of patients with no known risk factors for PE and outpatients. None of the environmental parameters were linked to PE severity.

Fig. 1 Incidence of PE correlated with air temperature, barometric pressure, PM2.5 and PM10. PM=particulate matter in µg/m ³ (micrograms per cubic meter); air temperature in degrees Celsius (°C); barometric pressure in hectopascal (hPa);barometric pressure, air temperature, PM ₁₀ and PM _2.5 are averaged (lag 0-9 days) with respect to the exposure time before the diagnosis of PE.

Conclusion: PE incidence was significantly associated with barometric pressure, PM_2.5, and PM₁₀, with higher environmental exposure linked to increased weekly PE cases. These results indicate that environmental factors, potentially exacerbated by climate change, may substantially contribute to the occurrence of PE.