Stability of the diurnal cortisol profile in children and adolescents

Abstract

SummaryThe diurnal cortisol profile has been implicated in multiple physical and mental health conditions in children and adolescents; however, current knowledge regarding the stability of the diurnal cortisol profile is largely based on adults. Developmental changes throughout childhood and adolescence warrant examination of the stability of the diurnal cortisol profile during this stage in the lifecourse. The aim of the present study was to conduct a comprehensive evaluation of the diurnal cortisol profile in children and adolescents. Participants (N = 233; M = 12.40, SD = 1.83; 44.2% girls) in the Healthy Heart Project collected saliva samples, completed demographic questionnaires, and recorded bed and waking time. Intra-class correlations were calculated to evaluate the stability of aggregate and single sample measures of the diurnal cortisol profile. Total cortisol concentration (AUC TG , AUC AG ) and maximum sample were the most stable cortisol measures (ICC avg = 0.54). Dynamic measures (AUC I , slope; ICC avg = 0.22) and other single sample measures (awake, lunch, dinner, bedtime, morning random, day random; ICC avg = 0.28) were less stable. Of the developmentally relevant covariates tested, sleep duration, adrenarche, and time of awakening were most associated with cortisol values. Altogether, the diurnal cortisol profile yielded moderate to high stability in children and adolescents. These findings can inform methodological decisions regarding cortisol sampling protocols for children and adolescents. KeywordsCortisol; Stability; Children; Adolescents; HPA axis; Methodology Cortisol, the end product of the hypothalamic pituitary adrenal (HPA) axis, is released in a circadian fashion and in response to stress. The circadian rhythm of cortisol, or the diurnal cortisol profile, has been implicated in multiple physical and mental health conditions in children and adolescents, including asthma (Wolf et al., 2008;Dreger et al., 2010), bipolar disorder (Ellenbogen et al., 2006), major depression (Van den Bergh and Van Calster, 2009;Adam et al., 2010), and sleep disturbances (El-Sheikh et al., 2008), among others. However, * Corresponding author. jennifer.mcgrath@concordia.ca (J.J. McGrath). Conflict of interest statementAll authors declare that they have no conflict of interest.Psychoneuroendocrinology. Author manuscript; available in PMC 2018 January 09.Published in final edited form as: Psychoneuroendocrinology. 2012 December ; 37(12): 1981-1989. doi:10.1016/j.psyneuen.2012.014. CIHR Author ManuscriptCIHR Author Manuscript CIHR Author Manuscript the measurement of cortisol varies widely, and few studies have considered the stability of the diurnal cortisol profile in children and adolescents.The diurnal cortisol profile is characterized by cortisol levels that peak roughly 30 min after awakening (morning acrophase) and gradually decline throughout the day, reaching nadir at bedtime (Fries et al., 2009). The diurnal cortisol profile is described using aggregate measures such as: the awakening response, diurna...

Sampling compliance for cortisol upon awakening in children and adolescents

“…To accurately capture the cortisol awakening response (CAR) individuals must be compliant with saliva sampling, which includes collecting a sample immediately upon waking (awake 0 sample). Compliance with this initial sample is also important for other measures of the diurnal cortisol profile (e.g., diurnal slope), as they too use the awake 0 sample in their calculation (Adam and Kumari, 2009;Rotenberg et al, 2012). To date, most research has exclusively focused on verifying self-reported sampling time with an objective measure of time, such as an electronic monitor that date-and time-stamps bottle opening and presumed time of saliva collection (e.g., MEMS Cap; Kudielka et al, 2003;Broderick et al, 2004).…”

“…Adult findings cannot be generalized to children and adolescents due to several developmental factors that influence the diurnal cortisol profile (Rotenberg et al, 2012). Developmental factors during childhood and adolescence influence awake 0 sampling (e.g., school routine, changes to sleep/wake pattern; Jessop and Turner-Cobb, 2008) as well as the cortisol response.…”

“…Feeling drowsy and less alert in the morning may contribute to children and adolescents forgetting to take the sample or less precision in the collection of their awake 0 sample. Relatedly, shorter sleep duration is associated with higher awake 0 cortisol levels (Rotenberg et al, 2012) and flatter diurnal slope (Zeiders et al, 2011). Further, adolescents commonly experience phase-shift delay, resulting in potentially greater morning fatigue and grogginess due to the propensity to sleep-in later, despite early school start times.…”

“…Finally, the cortisol response differs across childhood and adolescence, as total cortisol concentrations increase steadily (Lupien et al, 2001;Walker et al, 2001;Tornhage, 2002;Gunnar et al, 2009). Pubertal maturation is also associated with a flatter diurnal slope (Rotenberg et al, 2012), increased cortisol (Kiess et al, 1995;Oskis et al, 2009), and reduced CAR (Adam, 2006). Given that these developmental factors may influence awake 0 sampling and the cortisol response, and in turn, that awake 0 sampling is important to accurately capture CAR and the diurnal cortisol profile, it is necessary to consider whether children and adolescents are compliant with awake 0 sampling.…”

“…Previous methodological studies have examined the stability of CAR and the diurnal profile in children and adolescents (see Oskis et al, 2009;Rotenberg et al, 2012). However, the methodological issue regarding awake 0 compliance has yet to be examined in childhood.…”