We also explored the risk of suicide attempt among former smokers versus nonsmokers (no figure is given). The association was not statistically significant. The overall estimate of OR was 1.40 (95% CI: 0.50, 3.30; 2 studies; I2 = 46.6%; P = 0.171) based on cohort studies and 1.09 (95% CI: 0.75, 1.43; 5 studies; I2 = 54.8%; P = 0.065) based on case-control/cross-sectional studies.
