Child Temperament and Total Diurnal Cortisol in Out-of-Home Center-Based Child Care and in At-Home Parental Care.

The association between child temperament characteristics and total diurnal saliva cortisol in 84 children (M = 2.3 years, SD = 0.6) attending out-of-home, center-based child care and 79 children (M = 2.0 years, SD = 0.5) attending at-home parental care was examined. Saliva samples were collected during two consecutive days, that is, Sunday and Monday, with four samples taken per day. While children higher in surgency had higher total diurnal cortisol production, we did not find evidence that temperament moderated the associations between child-care context and total diurnal cortisol. Negative affectivity and effortful control were not related to cortisol output. Our findings suggest that temperamental surgency may be associated with higher total cortisol production in early childhood across child-care settings.

Sex differences in the associations between maternal prenatal distress and infant cortisol reactivity and recovery.

Previous research suggests that maternal prenatal psychological distress (PPD) is related to altered cortisol reactivity in the exposed child. There are indications for the sex differences in vulnerability for prenatal adversities that depend on the exposure and child outcome. Still, it is not known whether the association between maternal PPD and infant cortisol stress response is moderated by sex. In addition, the recovery phase of the cortisol stress response has not been given as much attention as reactivity. Our aim was to study the sex differences in the associations between self-reported maternal prenatal depressive-, anxiety- and pregnancy-related anxiety symptoms through gestational weeks 14, 24 and 34 and the saliva cortisol reactivity to and recovery from the acute stress among 10-week-old infants. The study population comprised of 363 mother-infant pairs from the FinnBrain Birth Cohort Study. We found evidence for sex-dependent associations between PPD exposure and infant cortisol response. A less steep recovery slope (-10 % per one SD increase in PPD [95 % CI = -18 to -2 %] and -8 % [-16 to 0 %] depending on the exposure) and a possibly less steep reactivity slope (-14 % [95 % CI = -25 to 0 %] and -10 % [-21 to 3 %]) were associated with higher PPD exposure in females. Of the PPD measures, the strongly intercorrelated, and thus combined, depressive and anxiety symptom score provided the most robust prediction of infant cortisol recovery. Our results demonstrate sexually dimorphic alterations in the functioning of the infant hypothalamus-pituitary-adrenal axis and especially in the functioning of the negative feedback loop of the axis after prenatal PPD exposure among healthy babies.

Toddlers' diurnal cortisol levels affected by out-of-home, center-based childcare and at-home, guardian-supervised childcare: comparison between different caregiving contexts.

Previous research suggests that attending non-parental out-of-home childcare is associated with elevated cortisol levels for some children. We aimed to compare diurnal saliva cortisol levels between children having out-of-home, center-based childcare or those having at-home, guardian-supervised childcare in Finland. A total of 213 children, aged 2.1 years (SD = 0.6), were drawn from the ongoing Finnish birth cohort study. Saliva samples were collected over 2 consecutive days (Sunday and Monday), with four samples drawn during each day: 30 min after waking up in the morning, at 10 am, between 2 and 3 pm, and in the evening before sleep. These results suggest that the shapes of the diurnal cortisol profiles were similar in both childcare groups following a typical circadian rhythm. However, the overall cortisol levels were on average 30% higher (95% CI: [9%, 54%], p = .004) with the at-home childcare in comparison with the out-of-home childcare group. Furthermore, a slight increase in the diurnal cortisol pattern was noticed in both groups and in both measurement days during the afternoon. This increase was 27% higher ([2%, 57%], p = .031) in the out-of-home childcare group during the out-of-home childcare day in comparison with the at-home childcare day. The elevated afternoon cortisol levels were partly explained by the afternoon naps, but there were probably other factors as well producing the cortisol rise during the afternoon hours. Further research is needed to define how a child's individual characteristic as well as their environmental factors associate with cortisol secretion patterns in different caregiving contexts.

An interlaboratory comparison between similar methods for determination of melatonin, cortisol and testosterone in saliva.

An interlaboratory comparison study for melatonin, cortisol and testosterone in saliva in which five laboratories participated is reported in this study. Each laboratory blindly measured eight samples prepared from natural saliva spiked with melatonin, cortisol and testosterone in the range 0-579 pmol/L for melatonin, 0-90 nmol/L for cortisol, and 0-622 pmol/L for testosterone. The recovery of spiked material for melatonin ranged from 91-110%, from 83-100% for cortisol and from 80-94% for testosterone. The content of natural hormone in saliva was estimated to be between 0.278 and 6.90 pmol/L for melatonin, 0.56 and 6.72 nmol/L for cortisol and 11.9 and 73.8 pmol/L for testosterone. This indicates a large interlaboratory variation. The present study emphasizes the importance of external quality control for the analysis of melatonin, cortisol and testosterone in saliva.