Biological Sensitivity to Context in Pakistani Preschoolers: Interactive Effects of Hair Cortisol and Family Wealth

• In Event: 1-078 - Stress Physiology in Early Childhood: Interactions with Context and Neurodevelopmental Implications in Understudied Populations

Integrative Statement

Young children in low- and middle-income countries (LMIC) face severe adversity which is linked with poorer developmental outcomes (Black et al., 2013; Walker et al., 2011), and these associations seem to vary as a function of the child’s gender (Escueta et al., 2014). Children’s stress physiology can shed light on why children are differentially susceptible to adverse experiences (Obradović, 2016). However, no known studies have examined whether the effects of environmental adversity on developmental outcomes in LMIC contexts are moderated by children’s stress physiology. Thus, the present study is the first to provide evidence of biological sensitivity to context in LMIC contexts by examining the interactive effects of hair cortisol, an indicator of chronic physiological stress regulation, and family wealth on preschoolers’ cognitive and social-emotional skills. Further, we test whether these effects differ by gender.

This study draws on a highly-disadvantaged sample of 1,320 four-year-olds living in rural Pakistan. Family wealth was assessed using a composite measure of ownership of property, livestock, household assets, and dwelling characteristics (Vyas & Kumaranayake, 2006). Stress physiology was indexed by children’s hair cortisol, which reflects cortisol output over the last three months (Stalder & Kirschbaum, 2012). Executive functions were assessed with six developmentally- and culturally-appropriate tasks (α = .60). IQ was measured using a culturally-adapted version of the Wechsler Preschool and Primary Scale of Intelligence III (α = .92). Parents reported on behavioral problems (α = .72) and prosocial behaviors (α = .74) using the Strengths and Difficulties Questionnaire.

Since previous findings revealed significant associations between hair cortisol and family adversity only for girls (Obradović et al., 2015), regression models were run separately by gender. Interactions between hair cortisol and wealth was predictive of girls’ cognitive skills and boy’s behavioral problems (Table 1). Among girls, the association between wealth and cognitive skills was stronger for girls who had lower cortisol compared to those who had higher cortisol (see Figure 1a). Among boys, the negative association between wealth and behavioral problems was stronger for boys with lower cortisol compared to boys with higher cortisol (see Figure 1b).

The current study suggests that children with lower cortisol were more sensitive to their environments, as wealth was more strongly associated with positive outcomes among children with low cortisol compared to those with high cortisol. This provides evidence of vantage sensitivity, such that that children with low cortisol may be more responsive exclusively to positive environments (Pluess & Belsky, 2012). In contexts of high adversity where the majority of primary caregivers are illiterate and have never attended school, lower levels of hair cortisol were promotive of better developmental outcomes only for children who were exposed to relatively higher levels of family wealth and resources. These findings differ from research in high-income contexts where high cortisol is promotive for children from more advantageous backgrounds but is associated with poor outcomes for children who come from relatively more disadvantaged backgrounds (Obradović et al., 2010; 2016). We will discuss how the HPA axis may function differently in highly disadvantaged environments.

Authors

• Emma Louise Armstrong-Carter, University of North Carolina at Chapel Hill
  Presenting Author

• Jenna E. Finch, University of Nebraska-Lincoln
  Non-Presenting Author

• Muneera Rasheed, Aga Khan University
  Non-Presenting Author

• Aisha Yousafzai, Harvard University
  Non-Presenting Author

• Jelena Obradovic, Stanford University
  Non-Presenting Author