Avon & Wiltshire Mental Health Partnership NHS Trust; and Severn Postgraduate Medical Education School of Psychiatry, Health Education England, UK.
School of Psychological Science, University of Bristol; MRC Integrative Epidemiology Unit, University of Bristol; NIHR Biomedical Research Centre, University Hospitals Bristol NHS Foundation Trust, University of Bristol; and UK Centre for Tobacco and Alcohol Studies, University of Bristol, UK.
Br J Psychiatry. 2020 Dec;217(6):701-707. doi: 10.1192/bjp.2020.68.
Previous literature has demonstrated a strong association between cigarette smoking, suicidal ideation and suicide attempts. This association has not previously been examined in a causal inference framework and could have important implications for suicide prevention strategies.
We aimed to examine the evidence for an association between smoking behaviours (initiation, smoking status, heaviness, lifetime smoking) and suicidal thoughts or attempts by triangulating across observational and Mendelian randomisation analyses.
First, in the UK Biobank, we calculated observed associations between smoking behaviours and suicidal thoughts or attempts. Second, we used Mendelian randomisation to explore the relationship between smoking and suicide attempts and ideation, using genetic variants as instruments to reduce bias from residual confounding and reverse causation.
Our observational analysis showed a relationship between smoking behaviour, suicidal ideation and attempts, particularly between smoking initiation and suicide attempts (odds ratio, 2.07; 95% CI 1.91-2.26; P < 0.001). The Mendelian randomisation analysis and single-nucleotide polymorphism analysis, however, did not support this (odds ratio for lifetime smoking on suicidal ideation, 0.050; 95% CI -0.027 to 0.127; odds ratio on suicide attempts, 0.053; 95% CI, -0.003 to 0.110). Despite past literature showing a positive dose-response relationship, our results showed no clear evidence for a causal effect of smoking on suicidal ideation or attempts.
This was the first Mendelian randomisation study to explore the effect of smoking on suicidal ideation and attempts. Our results suggest that, despite observed associations, there is no clear evidence for a causal effect.
先前的文献表明，吸烟、自杀意念和自杀企图之间存在很强的关联。这种关联以前没有在因果推理框架中进行过检验，这可能对自杀预防策略有重要意义。
我们旨在通过观察分析和孟德尔随机化分析的三角测量，检验吸烟行为（开始吸烟、吸烟状况、吸烟量、终生吸烟）与自杀想法或自杀企图之间的关联的证据。
首先，在英国生物银行中，我们计算了吸烟行为与自杀想法或企图之间的观察关联。其次，我们使用孟德尔随机化来探索吸烟与自杀企图和意念之间的关系，使用遗传变异作为工具来减少残留混杂和反向因果关系引起的偏差。
我们的观察性分析表明，吸烟行为与自杀意念和企图之间存在关联，尤其是吸烟开始与自杀企图之间存在关联（优势比，2.07；95%置信区间 1.91-2.26；P < 0.001）。然而，孟德尔随机化分析和单核苷酸多态性分析并不支持这一点（终生吸烟对自杀意念的优势比为 0.050；95%置信区间 -0.027 至 0.127；自杀企图的优势比为 0.053；95%置信区间，-0.003 至 0.110）。尽管过去的文献表明存在正剂量-反应关系，但我们的结果没有显示吸烟对自杀意念或企图有明确的因果效应的证据。
这是第一项探索吸烟对自杀意念和企图影响的孟德尔随机化研究。我们的结果表明，尽管存在观察到的关联，但没有明确的因果效应证据。
