Giesbrecht Gerald F, Bryce Crystal I, Letourneau Nicole, Granger Douglas A
Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada; Alberta Children's Hospital Research Institute, Calgary, AB, Canada; Institute for Interdisciplinary Salivary Bioscience Research, Arizona State University, Tempe, AZ, USA.
Institute for Interdisciplinary Salivary Bioscience Research, Arizona State University, Tempe, AZ, USA; T. Denny Sanford School of Social and Family Dynamics, Arizona State University, Tempe, AZ, USA.
Psychoneuroendocrinology. 2015 Dec;62:149-58. doi: 10.1016/j.psyneuen.2015.08.009. Epub 2015 Aug 14.
Individual differences in the activity of the hypothalamic pituitary adrenal (HPA) axis are often operationalized using summary measures of cortisol that are taken to represent stable individual differences. Here we extend our understanding of a novel latent variable approach to latent trait cortisol (LTC) as a measure of trait-like HPA axis function during pregnancy. Pregnant women (n=380) prospectively collected 8 diurnal saliva samples (4 samples/day, 2 days) within each trimester. Saliva was assayed for cortisol. Confirmatory factor analyses were used to fit LTC models to early morning and daytime cortisol. For individual trimester data, only the daytime LTC models had adequate fit. These daytime LTC models were strongly correlated between trimesters and stable over pregnancy. Daytime LTC was unrelated to the cortisol awakening response and the daytime slope but strongly correlated with the area under the curve from ground. The findings support the validity of LTC as a measure of cortisol during pregnancy and suggest that it is not affected by pregnancy-related changes in HPA axis function.
下丘脑-垂体-肾上腺（HPA）轴活性的个体差异通常通过皮质醇的汇总测量来体现，这些测量被认为代表了稳定的个体差异。在此，我们拓展了对一种新颖的潜在变量方法的理解，即潜在特质皮质醇（LTC），将其作为孕期特质样HPA轴功能的一种测量方法。380名孕妇在每个孕期前瞻性地收集8份日间唾液样本（每天4份样本，共2天）。对唾液进行皮质醇检测。使用验证性因素分析将LTC模型拟合至清晨和日间皮质醇数据。对于各个孕期的数据，只有日间LTC模型拟合良好。这些日间LTC模型在不同孕期之间高度相关且在孕期内保持稳定。日间LTC与皮质醇觉醒反应和日间斜率无关，但与从基线开始的曲线下面积高度相关。这些发现支持了LTC作为孕期皮质醇测量指标的有效性，并表明它不受孕期HPA轴功能变化的影响。
