The current study results are consistent with previous cohort results in which a higher risk of suicide or suicidal behavior was observed among current smokers. (Hemenway et al. 1993; Tverdal et al. 1993; Doll et al. 1994; Miller et al. 2000a; Miller et al. 2000b; Tanskanen et al. 2000; Breslau et al. 2005; Iwasaki et al. 2005; Yaworski et al. 2011). The present study also confirms results of a recent meta-analysis of prospective cohort studies (Li et al. 2012). In the present study, current daily smoking, but not past smoking, was significantly associated with 2.7 times higher high risk of suicide. However, current smoking was associated with 1.8 times higher risk of suicide (95% CI=1.50–2.19) in the recent meta-analysis (Li et al. 2012). Results of the current study suggest a nonmonotonic dose-response relationship between the number of CPD and suicide risk, with a greater than fourfold increase in risk among heavy smokers (≥25 CPD). Likewise, Tanskanen et al. (2000) noted a dose-response relationship between the number of CPD and suicide risk among 36,527 men and women with mean follow-up of
