The effect of cumulative early life adversities, and their differential mediation through hair cortisol levels, on childhood growth and cognition: Three-year follow-up of a birth cohort in rural India

Association between parental well-being and preschooler stress measured as hair cortisol concentration: A prospective cohort study

Hair cortisol concentration (HCC) is a valuable biomarker for evaluating chronic stress in preschoolers. However, few studies have explored early life HCC and its associated factors. This prospective cohort study analysed the HCC in children aged 6-48 months and its associations with parental HCC as well as positive and negative parental mental health outcomes. We used data from the ongoing Longitudinal Examination Across Prenatal and Postpartum Health in Taiwan (LEAPP-HIT) project, conducted in Taipei between 2020 and 2024. Hair samples were collected from both parents and children in 177 families (91 samples obtained during pregnancy and 86 during the postpartum period). The parents also completed self-reported questionnaires. Multiple linear regression was conducted to analyse the data. We observed a significant positive correlation between parents' and preschoolers' HCC. Furthermore, maternal depression (adjusted beta coefficient [aβ] = 0.09, 95% confidence interval [CI] = 0.02, 0.16) and perceived stress (aβ = 0.15, 95% CI = 0.02, 0.26) were positively associated with preschoolers' HCC. By contrast, higher maternal eudaimonia was associated with lower HCC in preschoolers (aβ = -0.11, 95% CI = -0.20, -0.01). For parents, maternal depression, anxiety, and perceived stress were independently associated with an increased HCC during the postnatal period, whereas maternal eudaimonia was negatively associated with HCC. Our results indicate that both mothers and fathers affect children's responses to stress. Assessment of cortisol stress hormone concentrations through hair samples can be a key means of detecting preschoolers' stress levels and enabling early intervention.

Fecal Microbiota and Hair Glucocorticoid Concentration Show Associations with Growth during Early Life in a Pig Model

Identifying characteristics associated with fast or slow growth during early life in a pig model will help in the design of nutritional strategies or recommendations during infancy. The aim of this study was to identify if a differential growth during lactation and/or the nursery period may be associated with fecal microbiota composition and fermentation capacity, as well as to leave a print of glucocorticoid biomarkers in the hair. Seventy-five commercial male and female pigs showing extreme growth in the lactation and nursery periods were selected, creating four groups (First, lactation growth, d0−d21; second, nursery growth, d21−d62): Slow_Slow, Slow_Fast, Fast_Slow, and Fast_Fast. At d63 of life, hair and fecal samples were collected. Fast-growing pigs during nursery had higher cortisone concentrations in the hair (p < 0.05) and a tendency to have a lower cortisol-to-cortisone ratio (p = 0.061). Both lactation and nursery growth conditioned the fecal microbiota structure (p < 0.05). Additionally, fast-growing pigs during nursery had higher evenness (p < 0.05). Lactation growth influenced the relative abundance of eight bacterial genera, while nursery growth affected only two bacterial genera (p < 0.05). The fecal butyrate concentration was higher with fast growth in lactation and/or nursery (p < 0.05), suggesting it has an important role in growth, while total SCFA and acetate were related to lactation growth (p < 0.05). In conclusion, piglets’ growth during nursery and, especially, the lactation period was associated with changes in their microbiota composition and fermentation capacity, evidencing the critical role of early colonization on the establishment of the adult microbiota. Additionally, cortisol conversion to cortisone was increased in animals with fast growth, but further research is necessary to determine its implications.