Association between salivary cortisol levels and subclinical measures of atherosclerosis: The Multi-Ethnic Study of Atherosclerosis

Researchers have hypothesized that stress, through the dysregulation of the hypothalamic-pituitary-adrenal axis, results in poor cardiovascular disease (CVD) outcomes. Cortisol, a stress hormone with metabolic, immunologic and homeostatic functions, also has numerous physiologic effects relevant to development of CVD. The purpose of this study is to investigate the association between diurnal salivary cortisol rhythms and measures of subclinical atherosclerosis. Few past studies have explored this association. Three subclinical measures of atherosclerosis were evaluated: coronary calcium (assessed by chest computed tomography), intima media thickness (IMT) and stenosis (> 25% narrowing) and ankle-brachial index (a ratio of < 1.1 indicates high risk for peripheral artery disease (PAD)). Salivary cortisol samples were collected 6 times per day over 3 days: at awakening, 30 minutes later, at 1000h, noon, 1800h and at bedtime. We used piecewise linear mixed models with knots at 30 and 120 minutes after wake-up to model cortisol. Data were collected from 969 black, white and Hispanic adults age 48 to 90 years. Preliminary results adjusted for age, race, sex, day and wake-up time show those at high risk for PAD had 11.6% less cortisol at wake-up (95% confidence interval (CI): -20.9%, -3.0%) and 5.8% less pronounced early decline (CI: -0.2%, 12.3%). We found no association between cortisol and coronary calcium, IMT and stenosis. The literature in this area remains mixed; however, this study is an improvement because of its large sample size, diverse study population, and improved cortisol measurement.