Prospective association between tobacco smoking and death by suicide: a competing risks hazard analysis in a large twin cohort with 35-year follow-up

Abstract

BackgroundThe relationship between smoking and suicide remains controversial.MethodA total of 16 282 twin pairs born before 1958 in Finland and alive in 1974 were queried with detailed health and smoking questionnaires in 1975 and 1981, with response rates of 89% and 84%. Smoking status and dose, marital, employment, and socio-economic status, and indicators of psychiatric and somatic illness were assessed at both time points. Emergent psychiatric and medical illness and vital status, including suicide determined by forensic autopsy, were evaluated over 35-year follow-up through government registries. The association between smoking and suicide was determined in competing risks hazard models. In twin pairs discordant for smoking and suicide, the prospective association between smoking and suicide was determined using a matched case–control design.ResultsSmokers had a higher cumulative suicide incidence than former or never smokers. Heavy smokers had significantly higher suicide risk [hazard ratio (HR) 3.47, 95% confidence interval (CI) 2.31–5.22] than light smokers (HR 2.30, 95% CI 1.61–3.23) (p = 0.017). Compared with never smokers, smokers, but not former smokers, had increased suicide risk (HR 2.56, 95% CI 1.43–4.59), adjusting for depressive symptoms, alcohol and sedative–hypnotic use, and excluding those who developed serious somatic or psychiatric illness. In twin pairs discordant for smoking and suicide, suicide was more likely in smokers [odds ratio (OR) 6.0, 95% CI 2.06–23.8].ConclusionsAdults who smoked tobacco were more likely to die by suicide, with a large, dose-dependent effect. This effect remained after consideration of many known predictors of suicide and shared familial effects, consistent with the hypothesis that exposure to tobacco smoke increases the risk of suicide.

Predictors of Neuropsychiatric Adverse Events with Smoking Cessation Medications in the Randomized Controlled EAGLES Trial

“…That smoking and suicidal thinking and behaviors are linked is well established. [23][24][25] However, our finding that past SI/SB predicts the likelihood of one experiencing a serious NPS adverse effect during a medication-assisted quit attempt is novel. Moreover, that prior history of SI/SB was independently associated with elevated risk-even after considering other factors such as measures of cigarette addiction itself or of psychiatric illness-related characteristics-speaks to the potential value of obtaining such a history in all smokers who are attempting to quit smoking.…”

Examining the effect of smoking on suicidal ideation and attempts: A triangulation of epidemiological approaches

“…The World Health Organisation (WHO) has recognised this significant public health problem and the need for comprehensive suicide prevention strategies, however at present there is limited evidence of sustained reductions in suicides rates 1 . Studies of the relationship between cigarette smoking and suicide have demonstrated a strong association between current cigarette smoking and suicide-related behaviours characterised as ideation, plans, attempts and suicide related death [3][4][5][6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] . These associations have been shown to have positive dose-response relationships 7,8,14 that remain after adjustment for potential confounding variables such as psychiatric symptoms 5 , familial risk factors 17 , socio-economic characteristics 6 and alcohol consumption 18 .…”

“…However, there is an alternate possibility, that smoking acts as a causative agent 11 . A number of possible biological pathways have been explored 7 , including evidence that smoking lowers the levels of serotonin 15 and monoamine oxidase A and B 23 .…”

Identifying Potential Causal Risk Factors for Self-Harm: A Polygenic Risk Scoring and Mendelian Randomisation Approach

“…A range of individual vulnerabilities and traits can potentially lead to self-harm, such as psychiatric illnesses, 6 substance use, 7–9 cognitive abilities, 10 personality traits 11 and physical traits. 12 Although associations between these risk factors and self-harm have been shown in numerous observational studies, causality is difficult to infer reliably.…”

“…The aforementioned PRS studies with mixed results were limited in several ways. Firstly, these studies focused on PRS for psychiatric disorders or psychiatric symptoms, and did not include potential risk factors from other domains, such as substance use 7–9 , cognitive abilities, 10 personality traits 11 and physical traits. 12 Secondly, with two exceptions, 21,25 none of the studies had investigated SSH and NSSH simultaneously.…”