Center for Interdiscplinary Salivary Bioscience Research, Johns Hopkins University, Baltimore, MD, USA.
Psychoneuroendocrinology. 2013 Mar;38(3):367-75. doi: 10.1016/j.psyneuen.2012.06.013. Epub 2012 Jul 20.
In the present study, we employ a longitudinal design and a generalizability framework to examine the sources of variance in the diurnal rhythm of salivary α-amylase (sAA). The sample consisted of 122 first-year law students (55% male, mean age=23.9 years), who collected five saliva samples on each of three consecutive days at each of five data collection waves. In total, over 6900 saliva samples were collected, which allowed us to examine the properties of diurnal variation in sAA in great detail. Systematic individual differences accounted for 15-29% of the variability in the awakening response and diurnal slope, and for 61-65% of the variation in overall daily levels (i.e., diurnal mean, area under the curve with respect to ground [AUCg]). Although less than 1% of the variation was due to differences between waves and between days, the generalizability analyses revealed that between 16% and 17% of the variance in the diurnal mean, slope and AUCg is due to person by wave interactions, indicating that individuals vary in their biological sensitivity to environmental influences. In sum, this study documents sufficient stability and variation in diurnal sAA to warrant future studies on the origins and consequences of alterations in the diurnal rhythm of sAA worthwhile, and proposes guidelines on obtaining reliable measures.
在本研究中，我们采用纵向设计和可推广性框架来研究唾液α-淀粉酶（sAA）昼夜节律变化的来源。样本包括 122 名一年级法律系学生（55%为男性，平均年龄为 23.9 岁），他们在五个数据采集波的每三天连续五天采集五次唾液样本。总共采集了超过 6900 个唾液样本，这使我们能够详细研究 sAA 昼夜变化的特性。系统的个体差异解释了觉醒反应和昼夜斜率变异性的 15-29%，以及日间总体水平（即日间均值、相对于基线的曲线下面积 [AUCg]）变异性的 61-65%。尽管只有不到 1%的变异是由于波之间和天之间的差异造成的，但可推广性分析表明，日间均值、斜率和 AUCg 的变异性有 16%-17%是由于人与波之间的相互作用造成的，这表明个体在对环境影响的生物敏感性方面存在差异。总之，本研究记录了足够的昼夜 sAA 稳定性和变异性，值得进一步研究 sAA 昼夜节律变化的起源和后果，并提出了获取可靠测量值的指导方针。
