Rudolph Kara E, Sánchez Brisa N, Stuart Elizabeth A, Greenberg Benjamin, Fujishiro Kaori, Wand Gary S, Shrager Sandi, Seeman Teresa, Diez Roux Ana V, Golden Sherita H
Am J Epidemiol. 2016 Mar 1;183(5):497-506. doi: 10.1093/aje/kwv280. Epub 2016 Feb 22.
Evidence of the link between job strain and cortisol levels has been inconsistent. This could be due to failure to account for cortisol variability leading to underestimated standard errors. Our objective was to model the relationship between job strain and the whole cortisol curve, accounting for sources of cortisol variability. Our functional mixed-model approach incorporated all available data-18 samples over 3 days-and uncertainty in estimated relationships. We used employed participants from the Multi-Ethnic Study of Atherosclerosis Stress I Study and data collected between 2002 and 2006. We used propensity score matching on an extensive set of variables to control for sources of confounding. We found that job strain was associated with lower salivary cortisol levels and lower total area under the curve. We found no relationship between job strain and the cortisol awakening response. Our findings differed from those of several previous studies. It is plausible that our results were unique to middle- to older-aged racially, ethnically, and occupationally diverse adults and were therefore not inconsistent with previous research among younger, mostly white samples. However, it is also plausible that previous findings were influenced by residual confounding and failure to propagate uncertainty (i.e., account for the multiple sources of variability) in estimating cortisol features.
工作压力与皮质醇水平之间联系的证据并不一致。这可能是由于未能考虑皮质醇的变异性，导致标准误差被低估。我们的目标是建立工作压力与整个皮质醇曲线之间的关系模型，同时考虑皮质醇变异性的来源。我们的功能混合模型方法纳入了所有可用数据——3天内的18个样本——以及估计关系中的不确定性。我们使用了动脉粥样硬化应激I多族裔研究中的在职参与者以及2002年至2006年期间收集的数据。我们在大量变量上使用倾向得分匹配来控制混杂因素。我们发现工作压力与较低的唾液皮质醇水平以及较低的曲线下总面积相关。我们发现工作压力与皮质醇觉醒反应之间没有关系。我们的研究结果与之前的几项研究不同。我们的结果可能对于中老年、种族、民族和职业多样的成年人来说是独特的，因此与之前针对较年轻、大多为白人样本的研究并不矛盾。然而，之前的研究结果也有可能受到残余混杂因素以及在估计皮质醇特征时未能传播不确定性（即考虑多种变异性来源）的影响。
