Socioeconomic status disparities affect children's anxiety and stress-sensitive cortisol awakening response through parental anxiety.

Socioeconomic status (SES) disparities have profound impacts on child development and health, which are linked to negative emotions and alterations in the integrity of stress-sensitive hypothalamus-pituitary-adrenal (HPA)-axis system. However, its underlying psychophysiological mechanisms remain poorly understood. Here we investigate how family SES, in concert with parental anxiety, affects children's anxiety and their integrity of HPA-axis system in two studies involving a total of 1318 children and their parents. In Study 1 with a cohort of 1088 children and their parents, we found that low-SES children relative to high-SES ones experienced a higher level of anxiety mediated by increasing parental anxiety. In Study 2 with an independent cohort of 230 children and their parents, we found that low-SES children exhibited an increase in pre-bedtime basal cortisol but a decrease in cortisol awakening response (CAR). Structural equation modeling (SEM) further revealed that the association between low SES and children's reduced CAR was mediated by increased parental and child anxiety. Our findings suggest that low-SES children are more vulnerable to anxiety and altered HPA-axis integrity, most likely mediated through increased parental anxiety.