Role of real and perceived exposures to multiple pollutants on depression symptoms

Previous studies showed links between exposure to environmental pollutants (e.g. air pollution and noise) and depression symptoms. Others underlined the role of perceived exposure on depression symptoms (e.g. electromagnetic fields). The aims of this study are to investigate how real (measured) and perceived exposures to several pollutants relate (1) to each other and (2) to depression symptoms. This cross-sectional study focuses on individual exposure to fine particles (PM2.5), noise (Lden: noise level weighted over day-evening-night), and extremely low-frequency magnetic fields (ELF-MF). It gathered the participation of 490 inhabitants of Brussels (Belgium) who wore monitoring devices to measure their multiple exposures for 24 hours. They self-reported their perceived exposures to the three pollutants of interest, and filled in a standardised depression symptoms questionnaire (PHQ-9). Data analyses involved hierarchical clustering of perceived exposure items. Perceived exposure clusters were first tested for their potential association with measured exposure using Kruskall-Wallis tests. In a second step, linear models were applied to identify potential associations between perceived/measured exposure and the score of depression. Preliminary results showed no significant differences in the levels of measured exposure to ELF-MF between the 5 clusters of perceived exposure to ELF-MF (X2= 4.87, p-value= 0.29). First step bivariate analysis (accepted signif. p-value <0.25) showed significant associations between both perceived (p = 0.24) or measured (p = 0.14) exposure to PM2.5, and depression. A stronger association was observed between perceived exposure to noise and depression (p = 0.003), but no association was observed with measured noise exposure (p = 0.79). These results underline the importance of air quality policies to protect mental health. They also support previous results showing the importance of perception in mental health issues.

Key messages

• Perceived exposure to a pollutant is not necessarily linked to actual exposure, however it may show a stronger association with depression symptoms than actual exposure.

• Both measured and perceived air pollution (PM2.5) show links with depression, highlighting the need for strong air‑quality policies.