The relationship between environmental chaos and diurnal cortisol levels of preschoolers

Cortisol is a widely used biomarker of the hypothalamic-pituitary-adrenal (HPA) axis of stress system. The aim of the present study was to investigate the main, additive and interactive role of chaotic home and daycare environment on preschoolers' diurnal cortisol levels, above and beyond socioeconomic status (SES). Participants were 75 preschoolers (47-to-83-months old), their mothers and teachers. Chaos was measured by CHAOS and LECP scales for home and daycare, respectively. SES was calculated as the standardized average of income and parental education. HPA-axis activity was measured as diurnal salivary cortisol. Samples were collected in the morning and afternoon, for two days at home and daycare. Diurnal slopes were calculated by subtracting afternoon values from morning values. Replicating previous research, diurnal slopes were higher at home compared to daycare, indicating a steeper decrease from morning to afternoon. Hierarchical linear regression analyses were conducted to test the main hypotheses. No main contributions of home or daycare chaos on relevant cortisol measures were observed. Contrary to expectations, daycare chaos was positively associated with home diurnal slope, whereas home chaos was uniquely and positively associated with daycare diurnal slope, over and above SES. An interaction was observed on individual daycare cortisol levels, suggesting a dual risk. Findings were discussed in terms of the possible adaptive role of mild stressors across different microsystems for low-risk samples and other factors in light of previous research.