Cortisol Elevations in Racially Minoritized Young Children and Their Parents

• In Event: Cortisol as a Stress Biomarker: Associations with Socioeconomic Risks, Racial Inequalities, and Family-Based Interventions

Abstract

Early life stress increases mental and physical health risks (Anda et al., 2010), and dysregulation of the stress hormone cortisol is a key mechanism through which these risks are transmitted into adulthood (McEwen, 2006). The hypothalamic-pituitary adrenal (HPA) axis, which produces cortisol, is shaped by early experiences (Gunnar & Talge, 2008). Race and ethnicity play a role in biological stress (Berry et al, 2016); however, most prior research has focused on middle childhood and adolescence (Tackett et al, 2017). Less is known about race and cortisol in early childhood, when the HPA axis is developing rapidly. Cortisol is deposited in hair as it grows, indexing chronic biological stress, but one complication is that African American hair grows more slowly than Non-Hispanic White hair (Loussouarn, 2001). Higher hair cortisol concentration (HCC) has been reported in young Black children (Palmer et al, 2013), but the extent to which this finding reflects hair growth rates versus early life stress is unclear. Socioeconomic status (SES) is linked to cortisol dysfunction (Flom et al., 2017), and is often confounded with race. We examined hair and salivary cortisol in young children in relation to race and SES.

Method: Hair samples from children (N=181, 11-42 months) and parents were assayed for HCC to index chronic biological stress. Parents collected 3 days of child salivary cortisol at home to yield diurnal cortisol slope, indexing daily biological stress regulation. Income-to-needs ratio relative to the federal poverty line was computed from parent-reported family income and household composition. Based on parent report, children were classified as White (N=100), Black (N=18), Asian American (N=21), and Hispanic (N=29).

Results: Child salivary cortisol slope varied by race, (F(3,139)=3.27,p=.02), such that Black children had a flatter slope than Asian Americans (p=.04 following Bonferroni corrections). Child and parent HCC also varied by race (F(3,153)=3.93,p=.01; F(3,164)=7.59,p<.001) such that Hispanic children had higher HCC than White children, p=.02, and Black parents had higher HCC than White parents, p<.001. When income-to-needs ratio was covaried, main effects of race remained significant for child cortisol slope (p=.004) and parent HCC (p=.001), and there was a nonsignificant trend (p=.05) for child HCC.

Discussion: Young children in racially minoritized groups had greater chronic and daily biological stress than White and Asian American children. Specifically, Hispanic children had higher HCC than White children, indexing chronic biological stress. Black children had a flatter diurnal slope than Asian American children, indexing dysregulated daily cortisol rhythms. HCC in Hispanic and Black children was similar, suggesting that elevated biological stress in Black children cannot be wholly attributed to slower hair growth. Black parents had higher HCC than White parents, which has implications for their children’s biological stress given prior findings that parent HCC predicts child HCC longitudinally (Flom et al., 2017). These results largely persisted after controlling for SES, indicating race is a specific risk factor. Structural racism may shape the development of biological stress systems in early childhood, with long-term implications for mental and physical health in adulthood.

Authors

• Amanda R Tarullo, Boston University
  Presenting Author

• Valeria Lazaro, Boston University
  Non-Presenting Author

• Amos Mwaura, Boston University
  Non-Presenting Author

• Katie Kao
  Non-Presenting Author

• Charu Tuladhar, Boston University
  Non-Presenting Author

• Jerrold Meyer, UMass-Amherst
  Non-Presenting Author