Skov-Ettrup Lise S, Nordestgaard Børge G, Petersen Christina B, Tolstrup Janne S
National Institute of Public Health, University of Southern Denmark, Copenhagen, Denmark;
Department of Clinical Biochemistry and The Copenhagen General Population Study, Copenhagen University Hospital, Herlev, Denmark.
Nicotine Tob Res. 2017 Jan;19(1):32-38. doi: 10.1093/ntr/ntw186. Epub 2016 Aug 3.
Increasing evidence suggests that smoking influences mental health negatively. This study investigated whether high tobacco consumption is causally related to psychological distress in a Mendelian randomization design, using a variant in the nicotine acetylcholine receptor gene CHRNA3-known to influence individual tobacco consumption-as instrumental variable for tobacco consumption.
Data from 90 108 participants in the Copenhagen General Population Study was used. Exposures included self-reported cigarettes/day and pack years and the CHRNA3 rs1051730 genotype as instrumental variable for tobacco consumption. Three dimensions of psychological distress were studied: Stress, fatigue, and hopelessness. Analyses with the CHRNA3 genotype were stratified by smoking status.
Self-reported amount of smoking was associated with all three dimensions of psychological distress. For instance among participants smoking 30 cigarettes/day or more, the odds ratio (OR) for stress was 1.67 (95% confidence interval [CI] 1.47-1.89) compared to never-smokers. Corresponding ORs for fatigue and hopelessness were 2.18 (95% CI 1.92-2.47) and 3.08 (95% CI 2.62-3.62). Among current smokers, homozygotes and heterozygotes for the CHRNA3 genotype had higher tobacco consumption than noncarriers. Nevertheless, the CHRNA3 genotype was not associated with psychological distress neither in current nor in former or never-smokers. For instance among current smokers, the OR for stress was 1.02 (95% CI 0.91-1.15) among homozygotes compared to noncarriers of the CHRNA3 genotype.
Though a strong association between tobacco consumption and psychological distress was found, there was no clear evidence that high tobacco consumption was causally related to psychological distress.
Smoking is associated with several mental health outcomes and smoking cessation is associated with improved mental health. Causality in the association between smoking and mental health is difficult to establish using observational data. Using a genotype known to influence tobacco consumption as instrumental variable for amount of smoking, we found no clear evidence of a direct causal path between high tobacco consumption and psychological distress. Whatever causes the strong association between tobacco consumption and psychological distress, the co-occurrence is important to consider both in interventions for smoking prevention and cessation.
越来越多的证据表明，吸烟会对心理健康产生负面影响。本研究采用孟德尔随机化设计，利用已知会影响个体烟草消费量的尼古丁乙酰胆碱受体基因CHRNA3中的一个变体作为烟草消费的工具变量，调查高烟草消费量是否与心理困扰存在因果关系。
使用了哥本哈根普通人群研究中90108名参与者的数据。暴露因素包括自我报告的每日吸烟量、吸烟包年数以及CHRNA3 rs1051730基因型作为烟草消费的工具变量。研究了心理困扰的三个维度：压力、疲劳和绝望感。对CHRNA3基因型的分析按吸烟状况进行分层。
自我报告的吸烟量与心理困扰的所有三个维度都相关。例如，在每天吸烟30支或更多的参与者中，与从不吸烟者相比，压力的优势比（OR）为1.67（95%置信区间[CI] 1.47 - 1.89）。疲劳和绝望感的相应OR分别为2.18（95% CI 1.92 - 2.47）和3.08（95% CI 2.62 - 3.62）。在当前吸烟者中，CHRNA3基因型的纯合子和杂合子比非携带者有更高的烟草消费量。然而，CHRNA3基因型在当前吸烟者、既往吸烟者或从不吸烟者中均与心理困扰无关。例如，在当前吸烟者中，与CHRNA3基因型非携带者相比，纯合子的压力OR为1.02（95% CI 0.91 - 1.15）。
尽管发现烟草消费与心理困扰之间存在强烈关联，但没有明确证据表明高烟草消费量与心理困扰存在因果关系。
吸烟与多种心理健康结果相关，戒烟与心理健康改善相关。使用观察性数据很难确定吸烟与心理健康之间关联的因果关系。使用已知会影响烟草消费的基因型作为吸烟量的工具变量，我们没有发现高烟草消费量与心理困扰之间存在直接因果路径的明确证据。无论是什么导致了烟草消费与心理困扰之间的强烈关联，在预防吸烟和戒烟干预中都很重要考虑到这种共存情况。
