Growth delay as an index of allostatic load in young children: predictions to disinhibited social approach and diurnal cortisol activity.

The goal of this study was to examine whether growth delay can serve as an index of allostatic load during early development, as it is well known that the activity of stress-mediating systems inhibits growth. The participants were children adopted internationally from institutional care (n = 36), children adopted internationally from foster care (n = 26), and nonadopted children (n = 35). For the adopted children, height for age and weight for height were assessed at adoption; for all children, disinhibited social approach (DSA; termed elsewhere as "indiscriminate friendliness") and diurnal cortisol were assessed at 6-8 years (M = 6.9 years). For internationally adopted children in general, and postinstitutionalized children specifically, linear growth delay assessed at the time of adoption was associated with more dysregulated behavior in response to an unfamiliar adult (i.e., greater DSA) and a more dysregulated diurnal cortisol rhythm (i.e., higher late afternoon and evening values). Further, among the most growth-delayed children, higher cortisol levels later in the day were correlated with DSA. The potential for using growth delay as an allostatic load indicator and the possible problems and limitations in its use in child populations are discussed.