Disease stigma and salivary stress biomarkers among adolescents and young adults with sickle cell disease

Abstract Introduction: Disease stigma is a known psychosocial stressor that impacts adolescents and young adults (AYA) living with sickle cell disease (SCD) who face heightened morbidity and mortality due during the transition from pediatric to adult medical care. Chronic stressors, such as stigma, are related to dysregulated stress response patterns, resulting in downstream morbidities in physical and mental health. Cortisol and salivary alpha-amylase (sAA) are biomarkers of the hypothalamic-pituitary-adrenal axis and the autonomic nervous system, respectively, each following diurnal profiles in normative samples. Cortisol rises sharply in the 30 minutes after waking and then steadily falls throughout the day, whereas sAA sharply drops in the 30 minutes after waking and then steadily rises. To our knowledge, no published study has examined the influence of any self-reported stressor on stress biomarkers among individuals living with SCD. The purpose of this study was to evaluate the association between disease stigma and physiological stress biomarkers among AYA with SCD. It was hypothesized that higher disease stigma would be associated with dysregulated biomarker patterns. Method: AYA with SCD (ages 16 to 25 years) were approached in hematology outpatient clinics to participate in a survey study. Participants completed the Measure of Sickle Cell Stigma, an 11-item measure that assesses internalized, exclusion, disclosure, and discrimination stigma on a 1-to-6 scale. They were also given the option to complete a 1-day, 4-sample, at-home saliva collection within 3 months of the baseline survey. AYA who opted into the salivary study were provided with materials to complete collection and log each sample within a mobile application at (1) waking, (2) 30 minutes after waking, (3) 8 hours after waking, and (4) bedtime. AYA stored saliva in their home freezer prior to returning samples to the study team in a sealed refrigerated envelope with an ice pack. Saliva samples were assayed at the Salimetrics' SalivaLab (Carlsbad, CA) for cortisol and sAA. Salivary cortisol was tested using a high sensitivity enzyme immunoassay, and sAA was tested using kinetic enzyme immunoassay. Cortisol and sAA values were log-transformed to reduce skewness, and the awakening response, awakening response slope, and diurnal slope were calculated for both biomarkers. Pearson correlations were used to assess bivariate associations, and multivariate linear regressions determined unique associations when controlling for participant age and gender. Results: Twenty-two AYA (Mean age = 20.4 SD = 2.76; 54.5% Female; 72.7% HbSS) completed the baseline survey and all 4 saliva samples. Internalized SCD stigma was inversely correlated with cortisol diurnal slope (r = -.43, p .050); however, internalized stigma was no longer a significant predictor of cortisol diurnal slope (ß = -.37, p = .108) when controlling for age and gender in a multivariate linear regression. Exclusion SCD stigma was inversely correlated with sAA awakening response (r = -.49, p = .022) and sAA awakening response slope (r = -.48, p = .023). Exclusion stigma remained a significant predictor of sAA awakening response (ß = -.41, p = .033) and sAA awakening response slope (ß = -.42, p = .047) when controlling for age and gender. Total stigma, disclosure stigma, and discrimination stigma were not related to any stress biomarker in bivariate or multivariate analyses. Conclusion: This study presents the first investigation linking psychosocial stress to stress biomarkers in SCD. Findings showed the opposite of the hypothesized associations, such that AYA who reported higher disease stigma also demonstrated normative diurnal stress patterns (i.e., decline in diurnal cortisol and decline in sAA after waking). This could be an indicator of physiological priming or vigilance for anticipated stress, such that the AYA who are experiencing stigma-related stressors have heightened awareness and anticipation of stressors and activate their stress physiology with appropriate reactivity. However, more research is needed to replicate this finding in a larger sample with more saliva collection days, prospective assessments to understand the long-term effects of stigma on stress biomarkers and disease outcomes, and an examination of effect modifiers such as coping and social support as sources of resilience against dysregulated stress responses in the face of disease stigma.