MRC Integrative Epidemiology Unit at the University of Bristol, Bristol, UK.
UK Centre for Tobacco and Alcohol Studies, School of Psychological Science, University of Bristol, Bristol, UK.
Psychol Med. 2019 Oct;49(13):2197-2205. doi: 10.1017/S0033291718003069. Epub 2018 Oct 25.
Despite the well-documented association between smoking and personality traits such as neuroticism and extraversion, little is known about the potential causal nature of these findings. If it were possible to unpick the association between personality and smoking, it may be possible to develop tailored smoking interventions that could lead to both improved uptake and efficacy.
Recent genome-wide association studies (GWAS) have identified variants robustly associated with both smoking phenotypes and personality traits. Here we use publicly available GWAS summary statistics in addition to individual-level data from UK Biobank to investigate the link between smoking and personality. We first estimate genetic overlap between traits using LD score regression and then use bidirectional Mendelian randomisation methods to unpick the nature of this relationship.
We found clear evidence of a modest genetic correlation between smoking behaviours and both neuroticism and extraversion. We found some evidence that personality traits are causally linked to certain smoking phenotypes: among current smokers each additional neuroticism risk allele was associated with smoking an additional 0.07 cigarettes per day (95% CI 0.02-0.12, p = 0.009), and each additional extraversion effect allele was associated with an elevated odds of smoking initiation (OR 1.015, 95% CI 1.01-1.02, p = 9.6 × 10-7).
We found some evidence for specific causal pathways from personality to smoking phenotypes, and weaker evidence of an association from smoking initiation to personality. These findings could be used to inform future smoking interventions or to tailor existing schemes.
尽管吸烟与神经质和外向等人格特质之间存在大量文献记载的关联，但对于这些发现的潜在因果性质知之甚少。如果能够解开人格与吸烟之间的关联，就有可能开发出针对特定人群的吸烟干预措施，从而提高戒烟的成功率和效果。
最近的全基因组关联研究（GWAS）已经确定了与吸烟表型和人格特质都密切相关的变异。在这里，我们使用公开的 GWAS 汇总统计数据以及英国生物库的个体水平数据来研究吸烟与人格之间的联系。我们首先使用 LD 得分回归估计性状之间的遗传重叠，然后使用双向孟德尔随机化方法来解开这种关系的本质。
我们发现吸烟行为与神经质和外向之间存在明显的中度遗传相关性。我们发现一些证据表明人格特质与某些吸烟表型之间存在因果关系：在当前吸烟者中，每增加一个神经质风险等位基因，每天吸烟量就会增加 0.07 支（95%CI 0.02-0.12，p = 0.009），而每增加一个外向效应等位基因，就会增加吸烟起始的几率（OR 1.015，95%CI 1.01-1.02，p = 9.6×10-7）。
我们发现了一些从人格到吸烟表型的特定因果途径的证据，以及从吸烟起始到人格的较弱的关联证据。这些发现可以用于为未来的戒烟干预措施提供信息，或定制现有的戒烟方案。
