*2.4. Statistical Methods*

The chi-square test, or the Fisher exact test was used to test the association between qualitative variables. The two independent sample *t*-test was used to compare the quantitative variables.

Odds ratio and the respective 95% CI was used to estimate the magnitude of the association between lifetime PTSD and several vulnerability factors. Simple and multinomial unconditional logistic regression was used to estimate the crude and adjusted odds ratio. The interaction between independent variables with lifetime PTSD was studied using logistic regression models.
