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This paper examined the relation of early environmental adversity associated with poverty to child resting or basal level of cortisol in a prospective longitudinal sample of 1,135 children seen at 7, 15, 24, 35, and 48 months of age. We found main effects for length of time in poverty, poor housing quality, African American ethnicity, and low positive caregiving behavior in which each was uniquely associated with an overall higher level of cortisol from age 7 months to 48 months. We also found that two aspects of the early environment in the context of poverty, adult exits from the home and perceived economic insufficiency, were related to salivary cortisol in a time dependent manner. The effect for the first of these, exits from the home, was consistent with the principle of allostatic load in which the effects of adversity on stress physiology accumulate over time. The effect for perceived economic insufficiency was one in which insufficiency was associated with higher levels of cortisol in infancy but with a typical but steeper decline in cortisol with age at subsequent time points.

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Relations of maternal and child characteristics to child cortisol reactivity to and recovery from emotional arousal were examined prospectively at approximately 7 months of age (infancy) and then again at approximately 15 months of age (toddlerhood). The sample was diverse and population based (N = 1,292 mother-infant dyads) and included families from predominantly low-income, rural communities. Maternal behavior, family income-to-need ratio and social advantage, and child temperament, attention, and mental development were assessed, and children's saliva was sampled before and after standardized procedures designed to elicit emotional arousal. Maternal engagement in infancy was associated with greater cortisol reactivity at the infancy assessment and with reduced overall cortisol level at the toddler assessment. Also at the toddler assessment, child attention, mental development, and temperamental distress to novelty were associated with increased cortisol reactivity and regulation, whereas temperamental distress to limitations and African American ethnicity were associated with reduced cortisol reactivity. Findings are consistent with prior work linking early caregiving to the development of the hypothalamic-pituitary-adrenal axis stress response system and with a conceptual model in which developing temperament is characterized by the interplay of emotional reactivity and the emergence of the ability to effortfully regulate this reactivity using attention.

This study examined the relationship between mother and infant adrenocortical levels and reactivity to an emotion eliciting task. The impact of intimate partner violence (IPV) on these relationships was assessed as a moderator. The sample (n = 702 mother-infant dyads) was racially diverse and from predominantly low-income, rural communities. During a home visit, the dyad's saliva was sampled before, 20 min, and 40 min after standardized tasks designed to elicit the infant's emotional arousal and later assayed for cortisol. Mothers completed self-report measures of their partner's violence, and parenting behaviors were assessed via structured interview and mother-child interactions. In response to the task, infants had positive, and mothers had negative, cortisol slopes. Contrary to expectations, there were no IPV-related differences in mean pretask cortisol levels or reactivity in the mothers or infants. Mother-infant dyads from households characterized by either (1) violence or (2) restrictive and punitive parenting behaviors exhibited correlated cortisol reactivity measured in response to the infant challenge task. The findings suggest that social contextual features of the early caregiving environment may influence individual differences in the coordination between maternal and infant adrenocortical reactivity.