Abstract A53: Plasma glucocorticogenic activity differs by race/ethnicity and alcohol intake among San Francisco Bay Area women

Breast cancer mortality is higher among non-Hispanic Black (NHB) and Hispanic women than non-Hispanic White (NHW) women in the United States. While various sociodemographic and lifestyle factors contribute to racial/ethnic disparities in breast cancer, the biologic processes underlying these associations remain poorly understood. Cortisol, the predominant endogenous glucocorticoid present in humans, is secreted in a diurnal pattern with the highest concentration occurring shortly after waking followed by a steady decline throughout the day. A flattened diurnal cortisol pattern (e.g., due to lower morning and/or elevated evening cortisol levels) is often observed among chronically stressed individuals and has been linked to poorer survival among breast cancer patients. We examined the association between race/ethnicity and other breast cancer risk factors with glucocorticogenic (G) activity, a measure that reflects plasma cortisol levels, in 503 controls from the San Francisco Bay Area Breast Cancer Study (SFBCS, 329 Hispanic, 100 NHB and 74 NHW women) using a low-cost Chemical-Activated LUciferase gene eXpression (CALUX) assay. Associations between G activity and sociodemographic and lifestyle factors were examined using multivariable linear regression models. Hispanic and NHB women had 14% (P = 0.016) and 16% (P = 0.007) lower morning G activity than NHW women, respectively. Additionally, we replicated our previously reported association between G activity and alcohol intake (women who drank >10 gm had 22% higher G activity than non-drinkers, P = 0.003). This association was only present in Hispanics and NHB. No statistically significant associations were observed between G activity and Indigenous American ancestry, body mass index, or neighborhood socioeconomic status. Our results indicate that NHB and Hispanic women may have a blunted cortisol awakening response potentially due to chronic stress. The increase in morning G activity observed with higher alcohol intake in Hispanics and NHB might reflect the use of alcohol as a stress-coping mechanism. Further research should assess the association between G activity and breast cancer survival in biospecimens from a prospective cohort so as to characterize the relationship between prediagnosis chronic stress and breast cancer outcome across different racial/ethnic groups. Citation Format: Rosemarie M. de la Rosa, Sylvia S. Sanchez, Phum Tachachartvanich, Heather Ruiz, Scarlett Lin Gomez, Esther M. John, Martyn T. Smith, Laura Fejerman. Plasma glucocorticogenic activity differs by race/ethnicity and alcohol intake among San Francisco Bay Area women [abstract]. In: Proceedings of the Tenth AACR Conference on the Science of Cancer Health Disparities in Racial/Ethnic Minorities and the Medically Underserved; 2017 Sep 25-28; Atlanta, GA. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2018;27(7 Suppl):Abstract nr A53.