Evaluation of cortisol and telomere length measurements in ethnically diverse women with breast cancer using culturally sensitive methods.

The under-representation of ethnic minority participants, who are more likely to be socially disadvantaged in biomedical research, limits generalizability of results and reductions in health disparities. To facilitate investigations of how social disadvantage "gets under the skin," this pilot study evaluated low-intensity methods for collecting hair and saliva samples from multiethnic breast cancer survivors (N = 70) and analysis of biomarkers of chronic stress (cortisol levels) and biological age (telomere length). Methods allowed for easy self-collection of hair (for cortisol) and saliva (for telomere lengths) samples that were highly stable for shipment and long-term storage. Measuring cortisol in hair as a biomarker of chronic stress was found to overcome many of the limitations of salivary cortisol measurements, and the coefficient of variation obtained using an ELISA-based approach to measure cortisol was within acceptable standards (16%). Telomere length measurements obtained using a qPCR approach had a coefficient of variation of <10% when the DNA extracted from the saliva biospecimens was of sufficient quantity and quality (84%). The overall response rate was 47%; rates were 32% for African-Americans, 39% for Latinas, 40% for Asians, and 82% for non-Latina Whites. Self-collection of hair and saliva overcame cultural and logistical barriers associated with collection of blood. Results support the use of these biospecimen collection and analysis methods among ethnically diverse and disadvantaged populations to identify biopsychosocial pathways of health disparities. Our tools should stimulate research to better understand how social disadvantage "gets under the skin" and increase participation of ethnic minorities in biomedical research.