Adam E K, Gunnar M R
School of Education and Social Policy, Northwestern University, 2115 North Campus Drive, Evanston, IL 60208-2610, USA.
Psychoneuroendocrinology. 2001 Feb;26(2):189-208. doi: 10.1016/s0306-4530(00)00045-7.
In 70 middle-class mothers of 2-year-old children, individual differences in mothers' morning cortisol levels, cortisol decreases across the day and average cortisol levels were predicted from demographic and medical control variables, maternal relationship functioning and home and work demands. For two days, salivary cortisol levels were measured in the morning immediately after wakeup, four times in the afternoon, and in the evening immediately prior to bedtime. Hierarchical linear modeling (HLM) growth curve analyses were used to estimate the intercept (early morning level), slope (steepness of decline in cortisol values across the day), and the average height of each mother's cortisol curve across the waking hours. HLM and multiple regression techniques were then used to predict individual differences in these parameters from the variables of interest. Time of day accounted for 72% of the variation in mothers' observed cortisol values across the day. After controlling for demographic and medical variables, positive relationship functioning was associated with higher morning cortisol levels and a steeper decline in cortisol across the day, while greater hours of maternal employment and a greater number of children in the household were associated with lower morning cortisol values and a less steep decline in cortisol levels across the day. Variables predicting higher morning values also predicted higher average cortisol levels, while variables predicting lower morning cortisol predicted lower average cortisol levels. The full model including selected control, relationship functioning and home and work demand variables accounted for 40% of the variance in mothers' morning cortisol values, 43% of the variance in cortisol slopes and 35% of the variability in mothers' average cortisol levels. This study presents the first evidence of associations between psychological variables and individual differences in the organization of cortisol levels across the waking day in normal adult women.
在70位有2岁孩子的中产阶级母亲中，母亲早晨皮质醇水平的个体差异、全天皮质醇水平的下降以及平均皮质醇水平可根据人口统计学和医学对照变量、母婴关系功能以及家庭和工作需求进行预测。连续两天，在早晨醒来后立即测量唾液皮质醇水平，下午测量4次，晚上睡前立即测量。采用分层线性模型（HLM）生长曲线分析来估计截距（清晨水平）、斜率（全天皮质醇值下降的陡度）以及每位母亲在清醒时间内皮质醇曲线的平均高度。然后使用HLM和多元回归技术从感兴趣的变量预测这些参数的个体差异。一天中的时间占母亲全天观察到的皮质醇值变化的72%。在控制了人口统计学和医学变量后，积极的关系功能与较高的早晨皮质醇水平以及全天皮质醇水平更陡峭的下降相关，而母亲工作时间越长和家庭中孩子数量越多与较低的早晨皮质醇值以及全天皮质醇水平下降较平缓相关。预测较高早晨值的变量也预测较高的平均皮质醇水平，而预测较低早晨皮质醇的变量则预测较低的平均皮质醇水平。包括选定的对照、关系功能以及家庭和工作需求变量的完整模型解释了母亲早晨皮质醇值方差的40%、皮质醇斜率方差的43%以及母亲平均皮质醇水平变异性的35%。本研究首次证明了心理变量与正常成年女性清醒日皮质醇水平组织的个体差异之间的关联。
