Relationship between hair cortisol and perceived chronic stress in a diverse sample

Hair cortisol (CORT) is a biomarker of chronic stress via long-term alterations in hypothalamus-pituitary-adrenal axis activity. Relationships to perceived stress measures, however, have rarely been specifically investigated. A diverse sample of 135 adults participated in a study assessing relationships between chronic stress indicator CORT to perceived stress and health indicators. CORT was not correlated to single perceived domain indices but with a global stress composite. Differences in objective and subjective measures were found for sociodemographics: racial/ethnic identity, sex and socioeconomic status (SES). Race by SES interactions predicted both CORT and perceived stress, but produced a complex and partially unanticipated pattern of results. For minorities, low and high SES showed the highest CORT, with mid-SES showing the lowest CORT; there was little change in perceived stress at all levels of SES. For non-minorities, mid-SES showed the highest CORT, with decreases in both CORT and perceived stress in high SES. The unanticipated findings of deleterious outcomes for high SES minorities highlight the importance of investigating potential stressors and moderators, including perceived discrimination and social identity. Moreover, these results suggest that CORT may not always correlate with single stress indices but may provide a global assessment of chronic stress, with implications for the allostatic load literature.