Longitudinal stability and developmental properties of salivary cortisol levels and circadian rhythms from childhood to adolescence

Abstract

This study aimed to (1) identify a stable, trait-like component to cortisol and its circadian rhythm, and (2) investigate individual differences in developmental trajectories of HPA-axis maturation. Multiple salivary cortisol samples were collected longitudinally across four assessments from age 9 (3rd grade) through age 15 (9th grade) in a community sample of children (N=357). Sophisticated statistical models examined cortisol levels and its rhythm over time; effects of age, puberty and gender were primarily considered. In addition to situation-specific and stable short-term or epoch-specific cortisol components, there is a stable, trait-like component of cortisol levels and circadian rhythm across multiple years covering the transition from childhood into adolescence. Youth had higher cortisol and flatter circadian rhythms as they got older and more physically developed. Girls had higher cortisol, stronger circadian rhythms, and greater developmental influences across adolescence. Distinguishing a stable, trait-like component of cortisol level and its circadian rhythm provides the empirical foundation for investigating putative mechanisms underlying individual differences in HPA functioning. The findings also provide important descriptive information about maturational processes influencing HPA-axis development.

Maternal Influence on Child HPA Axis: A Prospective Study of Cortisol Levels in Hair

“…This supports the theory that the stress response system may mature over time. 8,9,19,34,35 Among the perinatal factors, birth weight was significantly positively correlated to cortisol concentration at year 1. Similarly, being small or large for gestational age was connected to higher levels of cortisol.…”

“…This combined with the highly variable and reactive nature of the HPA axis, dependent on both psychological and physical factors, [16][17][18] makes it difficult to investigate a stable trait in the cortisol response. 19 It has recently become feasible to measure cortisol levels in hair over time. 20 This new biomarker could be valuable in assessing prolonged stress.…”

Evidence of a unique and common genetic etiology between the CAR and the remaining part of the diurnal cycle: A study of 14 year-old twins

“…This is surprising on many accounts. First, basal cortisol secretion undergoes important changes during the first two decades of life, with decreasing levels noted from toddlerhood to mid-childhood followed by an opposite trend (Adam, 2006;Gunnar et al, 2009;Shirtcliff et al, 2011). These maturational changes may depend on changing social environments (e.g., daycare to formal schooling), neuroendocrine factors (e.g., sex hormones) and brain structures and functioning (e.g., prefrontal cortex; (Gunnar and Vazquez, 2006;Lupien et al, 2009).…”

Variations in the sleep–wake cycle from childhood to adulthood: chronobiological perspectives

“…32 Across adolescence, cortisol levels increase and follow a flatter rhythm with age and pubertal development. 37,38 A sex difference also emerges across adolescence, with higher morning cortisol levels in girls, likely related to gonadal changes associated with pubertal development. 37,39,40 A bidirectional relationship between the timing and length of sleep and cortisol patterns in adolescents has been reported with a steeper decline in cortisol across the day associated with longer sleep.…”

“…37,38 A sex difference also emerges across adolescence, with higher morning cortisol levels in girls, likely related to gonadal changes associated with pubertal development. 37,39,40 A bidirectional relationship between the timing and length of sleep and cortisol patterns in adolescents has been reported with a steeper decline in cortisol across the day associated with longer sleep. 41 A circadian rhythm of core body temperature (CBT) is established in the 1st year of life, showing a peak during the day and a drop to a trough at night between 1 and 6 hours after sleep onset.…”