Associations Between Temperament and Diurnal Cortisol – Prospective Study of Children Aged 2 to 3.5 Years

• In Event: The impact of stress and coping on development: Measurement and mechanisms

Abstract

Introduction
Child temperament is suggested to moderate stress responses in out-of-home childcare (Phillips et al. 2011), and children higher in negative affectivity, social fearfulness and aggressiveness have shown higher cortisol levels in out-of-home childcare when compared to days at home (Geoffroy et al. 2006). Furthermore, temperament may contribute to child stress regulation independent of the environment. Our recent findings indicate that higher surgency/extroversion is associated with higher total diurnal cortisol production in 2-year-old children regardless of the childcare context, i.e. out-of-home childcare or at-home parental care (blinded 2020). However, more research in longitudinal settings is needed to assess the relevance for later development.

Aims and Hypotheses
We aimed to examine a) whether child temperament characteristics (i.e. negative affectivity, surgency/extroversion or effortful control) were associated with diurnal cortisol production and b) whether the associations between temperament and cortisol output would be similar across childcare settings at the age of 3.5 years c) whether child age from 2 to 3.5 years would moderate the association between temperament and cortisol production. Based on our previous study, we hypothesized that higher surgency would be associated with higher total diurnal cortisol production in both childcare groups at the age of 3.5 years. This was based on the assumption that children higher in surgency are physiologically more reactive and surgency would play a general role in early childhood stress regulation.

Methods
The participants were drawn from the larger FinnBrain Birth Cohort Study (N=3808). At the age of 2 years a total of 84 children who participated in out-of-home childcare and 79 children in at-home parental care participated. At the age of 3.5 years a total of 68 in out-of-home childcare group and 21 in at-home parental care group continued. Four saliva cortisol samples were collected across two consecutive days (Sunday and Monday) in both age points. Child temperament was measured at the age of 2 using parent-reports of Early Childhood Behavior Questionnaire.

Results
Higher surgency was not associated with diurnal cortisol production at the age of 3.5 in either childcare group. No association between negative affectivity or effortful control and cortisol production was detected either. Child age moderated the association between surgency and diurnal cortisol production in the whole population as the association between surgency and cortisol decreased along with the increasing child age. The age effect seemed to be stronger among children in at-home parental care.

Discussion
In line with our prior work, the associations between temperament and diurnal cortisol production were similar across childcare contexts, suggesting that temperament plays little role in cortisol response to the childcare setting, at least in the Nordic childcare system. Our findings further suggest that the association between surgency and diurnal cortisol production diminishes along with the child age. This may be related to the maturation of child neurobiological systems involved in stress regulation, as well as the improved social-emotional skills during the early childhood years (Gunnar et al. 2007). Our finding has implications for understanding the periods of sensitivity in early childhood stress regulation in different childcare settings.

Authors

• Katja Tervahartiala, university of turku
  Presenting Author

• Saara Nolvi, University of Turku
  Non-Presenting Author

• Susanna Kortesluoma, University of Turku
  Non-Presenting Author

• Juho Pelto, University of Turku
  Non-Presenting Author

• Annarilla Ahtola, University of Turku
  Non-Presenting Author

• Hasse Karlsson, Turku University Hospital and University of Turku
  Non-Presenting Author

• Linnea Karlsson, University of Turku
  Non-Presenting Author