BACKGROUND: Suicide is a major public health problem, with some environmental risk factors.
OBJECTIVE: This meta-analysis study explored the association between short-term exposure to air pollution and suicide mortality, with an emphasis on different lag times.
METHODS: A systematic search was used to find relevant studies in databases including Scopus, Web of Knowledge, Pubmed, and Embase published up to 19 May 2020. The inclusion criteria included case-crossover or time-series studies assessing the association of criteria air pollutants with suicide mortality at different Lag Days of 0-7 (LD0 to LD7) and Cumulative Lags of 1-7 days (CL1 to CL7). Odds ratios (OR) were calculated with 95% confidence intervals (CI).
RESULTS: Of 1436 retrieved articles, 11 were eligible for data extraction, representing data on 283,550 suicides published between 2010 and 2019. The odds of suicide death increase with each 10 μg/m3 increase in the mean concentrations of NO2 at CL1 (1.013: 1.006-1.021), CL2 (1.028: 1.003-1.053), CL3 (1.035: 1.001-1.070), and LD2 (1.011: 1.001-1.022), SO2 at CL1 (1.024: 1.014-1.034), CL2 (1.030: 1.012-1.048), CL3 (1.029: 1.009-1.049), and CL4 (1.027: 1.005-1.049), O3 at CL6 (1.008: 1.000-1.016), PM10 at CL1 (1.004: 1.000-1.008), and PM2.5 at CL1 (1.017: 1.003-1.031). Besides, the odds of suicide death increases with each 0.5 mg/m3 increase in the mean concentration of CO at LD6 (1.005: 1.000-1.011). However, it decreased with increased O3 exposure at LD3 (0.997: 0.994-1.000).
CONCLUSIONS: The study supports a positive association between air pollution and suicide mortality. No immediate risk was elucidated but the possible effects seem to be exerted cumulatively.