Hair Cortisol Concentration as an Indicator of Chronic Stress among Ethnic/Racial Minority Young Adults

• In Event: 1-184 - Biomarkers of Chronic Stress, Disparities, and Development: Does Hair Cortisol Reflect Minority Experiences Across the Lifespan?

Integrative Statement

Ethnic/racial minorities are disproportionately exposed to stress, due in part to experiences of discrimination and unfair treatment. Scholars have begun to investigate physiological markers of stress such as salivary cortisol and cardiovascular indicators. However, the majority of research on biological markers has focused primarily on point estimates of acute stress, leaving open the question of whether and how biomarkers are developmentally cumulative and reflect more chronic stress exposure. The current study explores the association between discrimination and a biomarker of chronic stress. Our indicator of chronic stress includes assessing levels of cortisol in hair samples (“hair cortisol concentration”, HCC). Hair cortisol analysis is relatively new in developmental science especially applied to ethnic/racial minority populations. Cortisol is deposited in hair, as it grows at a rate of approximately 1 cm/month; approximating chronic stress levels.

Methods
In a diverse sample of 220 college students (28% Asian, 9% Black, 19% Latinx, 44% White; 66% female, 33% male, 1% other), the association between ethnic/racial discrimination and HCC was investigated. A 2cm sample of hair was taken from the posterior vertex of participants’ scalps, approximating cortisol levels over the last 2 months. The hair was ground into a fine powder and assayed with ELISA cortisol kits. Hair cortisol had a strong positive skew and data were log transformed for normality (x ̅ = 2.59, SD = .52, min = .96, max = 4.48). Participants also completed the Daily Life Experiences scale which includes 18 items referring experiences in the past 2 months (Harrell, 1994). Consistent with the literature, discrimination was relatively low frequency (x ̅ = 2.02, SD = 2.61, min = 0, max = 15.33).

Results
Asian and Black students reported the highest levels of discrimination (F(3) = 89.26, p < .001), significantly higher than Latinx and White students. In addition, Asian (but not Black) students also reported the highest levels of hair cortisol concentration (F(3) = 2.66, p < .05), levels that were significantly higher than the White students (difference = .27, SE = .10, p < .05) but not statistically different from Black or Latinx students. Despite ethnic/racial differences in both HCC and discrimination, there was no association between the two. HCC was also not significantly associated with self-reported stress, depression, self-esteem, somatic symptoms, or mood. This observation is consistent with a recent meta-analysis of 66 independent studies (124 samples) which failed to observe a significant association between HCC and self-reported stress (Stalder et al, 2017). However, also consistent with the meta-analysis (r = .15, .18; Stalder et al 2017), HCC was significantly associated with salivary cortisol (r = .29, p < .001) and anthropometric measures of BMI (r = -.20, p = .07). Recent analyses suggest that HCC levels have a weaker association with self-report assessments (Stalder et al, 2017), leaving open a discussion of how best to analyze datasets that include self-report and HCC indicators. The utility of adopting HCC methods for assessing chronic stress in diverse samples will be discussed.

Authors

• Tiffany Yip, Fordham University
  Presenting Author

• Yuen Mi Cheon, Fordham University
  Non-Presenting Author

• Paul Smith, Fordham University
  Non-Presenting Author