Caregiver depression is associated with hair cortisol in a low-income sample of preschool-aged children

Background: Caregiver depression and child temperamental characteristics such as effortful control have been associated with child dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis. Hair cortisol concentrations (HCC) has been increasingly adopted as an integrated marker of HPA axis activity. This study examined the associations between caregiver depressive symptoms, caregiver social support, child effortful control, and child HCC in a sample of a high-risk, low-income preschool-aged children. Methods: 154 caregivers comprised mostly of mothers and their children (2-to-5 years) who were enrolled in a birth cohort study conducted in poor urban neighborhoods of Sao Paulo, Brazil. Through personal interviews at their homes, caregivers provided ratings of their psychosocial experiences and of their child's behavior. Hair was sampled from children with at least a 3-cm hair length. Results: In a multivariable regression analysis, an unadjusted model showed child age to be negatively associated with HCC (beta = -0.32, p < .001). The adjusted model, which accounted for child age and sex, showed a positive relationship between caregiver depressive symptoms and HCC (beta = 0.22, p < .01). Caregiver social support and child effortful control were not associated with HCC. Conclusions: The elevated HCC among children with caregivers reporting greater depression risk is consistent with prior findings showing elevated HCC among children exposed to persistent stress. Stabilization of child HCC may be occurring within preschool children given the negative association between HCC and age. Greater research is needed to determine whether the effects of caregiver social support and effortful control can be captured through HCC.