Correlation between short-term air pollution exposure and unprovoked lung embolism. Prospective observational (Contamina-TEP Group).

Background: The aim was to analyze the temporal relationship between short-term air pollution exposure and acute symptomatic unprovoked pulmonary embolism (PE).

Patients/methods: We performed a prospective, multicenter study in consecutive patients diagnosed with acute symptomatic unprovoked PE from February 2012 to January 2013. We analyzed demographic and clinical data, patients' addresses, meteorological and air pollutants data (PM, SO, CO, NO, ozone emission data). We considered the number of days the patient had symptoms, and the study period constituted the previous 30 days. Likewise, the mean annual data of the reference season were calculated as well as the data of the 30-day study period corresponding to the same dates in the previous 3 years in order to obtain the monthly mean of the different pollutants for each period.

Results: A total of 162 patients with acute symptomatic PE were recruited (43.2% unprovoked PE). The air pollutants could be determined in 50% of the patients with unprovoked PE, and a final analysis was performed in 35 patients. In the multiple comparison analysis to verify a possible correlation between the study period and the annual median, only NO showed a statistically significant association (p = 0.009). When comparing the study period with the previous 3 years, only NO maintained a statistically significant association for the 3 study periods.

Conclusions: We found a relationship between short-term exposure to NO and the presence of unprovoked PE.