Background: Dysregulation of the hypothalamic-pituitary-adrenal (HPA-axis) has been suggested as an independent risk factor for ischemic heart disease. The aim of our study was to evaluate whether two markers of the HPA-axis activity, the level of salivary cortisol and the diurnal salivary cortisol pattern, are associated with atherosclerosis of the carotid arteries in an elderly population.

Methods and Results: 1866 participants of the Rotterdam Study, a population-based cohort study in the elderly, provided four salivary cortisol samples throughout one day and underwent ultrasonography to examine the presence of plaques in the common, internal and bifurcation sites of both carotid arteries. Two summary measures of the separate cortisol values were computed: area under the curve (AUC), which is a measure of total cortisol exposure while awake, and the slope, which is a measure of diurnal cortisol decline.

Results: Total cortisol exposure while awake (AUC) was associated with higher plaque scores ( = 0.08 per SD of AUC, 95% CI; 0.00 – 0.17, p-value = 0.04) in a fully adjusted linear regression model. Persons with an AUC in the highest tertile had a higher number of plaques of carotid arteries compared to those in the lowest tertile (3.08 versus 2.80, 95% CI of difference; 0.09 – 0.48, p-value = 0.005). There was no relation between diurnal cortisol decline and plaque score.

Conclusion: Our results support the hypothesis that increased total cortisol exposure is independently associated with atherosclerosis of the carotid arteries.