Association between particulate matter air pollution and risk of depression and suicide: systematic review and meta-analysis

Background Some recent studies examined the effect of ambient particulate matter (PM) pollution on depression and suicide. However, the results have been inconclusive. Aims To determine the overall relationship between PM exposure and depression/suicide in the general population. Method We conducted a systematic review and meta-analysis of case-crossover and cohort studies to assess the association between PM 2.5 (particles with an aerodynamic diameter of 2.5 µm or less) or PM 10 (particles with an aerodynamic diameter between 2.5 and 10 µm) exposure and depression/suicide. Results A total of 14 articles (7 for depression and 7 for suicide) with data from 684 859 participants were included in the meta-analysis. With a 10 µg/m 3 increase in PM 2.5 we found a 19% (odds ratio [95% CI] 1.19 [1.07, 1.33]) increased risk of depression and a marginally increased risk of suicide (odds ratio [95% CI] 1.05 [0.99, 1.11]) in the general population. We did not observe any significant associations between increasing exposure to PM 10 and depression/suicide. Sensitivity and subgroup analyses were used to determine the robustness of results. The strongest estimated effect of depression associated with PM 2.5 appeared in a long-term lag pattern (odds ratio [95% CI] 1.25 [1.07, 1.45], P P Conclusions The meta-analysis suggested that an increase in ambient PM 2.5 concentration was strongly associated with increased depression risk in the general population, and the association appeared stronger at long-term lag and cumulative lag patterns, suggesting a potential cumulative exposure effect over time. Declaration of interest None.