Infant sleep behaviors relate to their later cognitive and language abilities and morning cortisol stress hormone levels
Hernandez-Reif & Gungordu
The finding, in our words
Optimal sleep behaviours at 8 months positively predicted cognitive and language abilities at 14 months in infants. Salivary cortisol analysis also revealed that optimal toddler sleep correlated with higher morning cortisol, linking early sleep patterns to stress axis development.
A paraphrase to the Library’s standard, never the abstract. The source is one link away and is always the authority.
This study used home self-collected saliva samples to successfully monitor cytokines and cortisol in mothers and infants, finding that a community singing intervention significantly reduced salivary interleukin-6 levels in mothers with postnatal depression.
Higher lifetime trauma exposure in adolescent mothers was associated with higher evening salivary cortisol, and maternal trauma during pregnancy was associated with higher bedtime cortisol in infants, suggesting that self-collected saliva can capture diurnal cortisol patterns relevant to trauma research and decentralised sampling.
Among children of parents with bipolar disorder, saliva samples collected at home over two days showed that improvements in family organisation during a six-month prevention programme were associated with adaptive changes in hypothalamic-pituitary-adrenal axis activity, including elevated cortisol awakening response and steeper diurnal slope. These results indicate that decentralised saliva collection can capture clinically meaningful neuroendocrine responses to psychosocial interventions in at-risk paediatric populations.
A validated LC-MS/MS assay successfully measured 13 steroid hormones and two synthetic steroids in saliva, requiring only 50 microlitres, or down to 2 to 5 microlitres for nine analytes. This shows saliva's viability for non-invasive, patient-centric microsampling and decentralised monitoring in paediatric, neonatal and adult populations.
In a longitudinal cohort of 1,292 mothers, increased cortisol reactivity to children's distress at 15 months predicted higher harsh parenting at 24 months, and conversely, higher harsh parenting at 15 months predicted increased cortisol reactivity at 24 months. This bidirectional association suggests that salivary cortisol reactivity in early toddlerhood may flag risk for harsh parenting and that parenting stress can further alter maternal stress physiology, which is pertinent to decentralised monitoring of stress biomarkers via saliva.