Background: An increasing amount of empirical attention is focused on adrenocortical synchrony as an index of biobehavioral co-regulation between parent and child in the context of early child development. Working with an ethnically diverse community sample of children (N = 99, 50.5% male, ages 9-12), we collected saliva samples from mother-child dyads prior to and after a laboratory-based performance challenge task, and tested whether maternal overcontrol and child age moderated dyadic synchrony in cortisol. Results revealed that cortisol levels between mothers and children were significantly positively correlated at pretask for dyads with mean age and older children only, at 25-min post-task for all dyads, and at 45-min post-task for all dyads. Higher overcontrol/older child dyads exhibited a unique pattern of cortisol synchrony wherein at pretask, mother-child levels had the strongest positive correlation, whereas at 25 and 45 min, mother-child cortisol levels were significantly inversely correlated. These findings contribute to theory and research on parent-child relationships by examining parenting behavior, developmental stage, and adrenocortical synchrony in tandem.
Background: Adversity experienced early in life has the potential to influence physical health later in life. The stress-health relation may be partially explained by stress-related effects on cardiovascular risk factors. This study explored links between individual differences in trait-like variation in the activity of the hypothalamic-pituitary-adrenal (HPA) axis with cardiovascular risk factors in children. 474 children (M age=9.22years; 54% female; 83% Caucasian) were included in this study, in which cardiovascular risk was assessed using the following indices – triglycerides (TG), HDL-cholesterol (HDL-C), glucose (Glu); resting systolic and diastolic blood pressure, body mass index (BMI), waist-to-hip ratio, and % fat. Saliva samples were measured 3 times a day (waking, 30min post-waking and bedtime) over 3days (later assayed for cortisol). A latent trait cortisol (LTC) factor explained 43% of the variance in cortisol levels within and across days. Confirmatory factor analysis identified three cardiovascular risk factors: lipids (i.e., TG and HDL-C), blood pressure (i.e., systolic and diastolic), and body composition (i.e., BMI, Waist-to-hip ratio, and % fat). Lower salivary LTC was associated with higher lipids, higher blood pressure, and higher body composition. The findings further support the internal and external validity of the LTC construct, and may also advance our understanding of the link between interindividual differences in HPA axis activity and cardiovascular risk in middle childhood.