Exposure to ambient particulate matter increases blood count parameters with potential to mediate a cardiovascular event: results from a population-based study in Portugal

Variations in blood count parameters are potential mechanisms involved in the occurrence of cardiovascular events caused by particulate matter (PM) exposure. This study aims to estimate the effect of PM 10 exposure on blood count parameters with potential to mediate a cardiovascular event. We used data from 2211 participants of the 1st Portuguese Health Examination Survey (INSEF, 2015) with available information on blood count parameters and living within a 30-km radius of at least one air quality monitoring station with available PM 10 measurements. Generalised linear models were used to assess both short (3 days) and long-term effects (1 year) of PM 10 exposure on blood count parameters. Both short and long-term PM 10 effects on blood count parameters were found, with males and females affected in a different way. In the short-term scenario, we found a 2.76% (95% CI: 0.65–4.87) increase in white blood cells among females per each 10μg/m 3 PM 10 increment. Additionally, there was a 2.96% (95% CI: 0.80–5.12) increase in red cell distribution width (RDW), per each 10μg/m 3 PM 10 increment, among males, when considering the long-term scenario. In conclusion, we detected some sex-differential associations regarding the short and long-term effect of PM 10 exposure on blood count parameters with potential to mediate a cardiovascular event, namely on the RDW parameter, that were never been described. It is uncertain whether changes in blood count parameters due to PM 10 exposure constitute an adverse health outcome or it reflects only a normal immunity response. However, due to its potential to trigger cardiovascular events, it is essential to reduce PM 10 levels exposure to protect the population’s cardiovascular health.