Centre for Health Equity, Melbourne School of Population and Global Health, The University of Melbourne, Melbourne, Australia.
Work, Health and Wellbeing Unit, Population Health Research Centre, School of Health & Social Development, Deakin University, Melbourne, Australia.
J Public Health (Oxf). 2018 Jun 1;40(2):426-434. doi: 10.1093/pubmed/fdx070.
Previous studies suggest that poor psychosocial job quality is a risk factor for mental health problems, but they use conventional regression analytic methods that cannot rule out reverse causation, unmeasured time-invariant confounding and reporting bias.
This study combines two quasi-experimental approaches to improve causal inference by better accounting for these biases: (i) linear fixed effects regression analysis and (ii) linear instrumental variable analysis. We extract 13 annual waves of national cohort data including 13 260 working-age (18-64 years) employees. The exposure variable is self-reported level of psychosocial job quality. The instruments used are two common workplace entitlements. The outcome variable is the Mental Health Inventory (MHI-5). We adjust for measured time-varying confounders.
In the fixed effects regression analysis adjusted for time-varying confounders, a 1-point increase in psychosocial job quality is associated with a 1.28-point improvement in mental health on the MHI-5 scale (95% CI: 1.17, 1.40; P < 0.001). When the fixed effects was combined with the instrumental variable analysis, a 1-point increase psychosocial job quality is related to 1.62-point improvement on the MHI-5 scale (95% CI: -0.24, 3.48; P = 0.088).
Our quasi-experimental results provide evidence to confirm job stressors as risk factors for mental ill health using methods that improve causal inference.
以往研究表明较差的心理社会工作质量是心理健康问题的一个风险因素,但这些研究使用的传统回归分析方法无法排除反向因果关系、不可测量的时不变混杂因素和报告偏倚。
本研究结合了两种准实验方法来改善因果推断,更好地考虑这些偏差:(i)线性固定效应回归分析和(ii)线性工具变量分析。我们从包括 13 000 名工作年龄(18-64 岁)员工的 13 个年度队列数据中提取了 13 个年度波次的数据。暴露变量是自我报告的心理社会工作质量水平。使用的工具是两种常见的工作场所权利。结果变量是心理健康量表(MHI-5)。我们调整了可测量的时变混杂因素。
在调整了时变混杂因素的固定效应回归分析中,心理社会工作质量每增加 1 分,MHI-5 量表上的心理健康评分就会提高 1.28 分(95%CI:1.17,1.40;P<0.001)。当固定效应与工具变量分析相结合时,心理社会工作质量每增加 1 分,MHI-5 量表上的心理健康评分就会提高 1.62 分(95%CI:-0.24,3.48;P=0.088)。
我们的准实验结果提供了证据,证实工作压力源是导致心理健康不佳的风险因素,使用的方法改善了因果推断。