"The causes of flat slopes in cortisol or raised evening levels are unknown. It is unclear whether a flatter slope in cortisol is due to stress-related elevations, resulting from a stressful day, long-term changes in circadian regulation as a result of chronic stress, or impaired central negative feedback sensitivity of the HPA axis (particularly to melanocorticoid receptors) as recently described in obesity."
In addition, obesity was independently predictive of both cardiovascular and noncardiovascular mortality (HR, 2.10 and 1.72 respectively) based on analyses of bedtime cortisol. Fatigue was also predictive of both cardiovascular and noncardiovascular deaths (HR, 2.37 and 1.72 respectively), in analyses of bedtime cortisol. Interestingly, self-reported stress on day of cortisol sampling also was independently associated with cardiovascular deaths (HR, 3.45).
"Our findings are novel in that they suggest a cause-specific association with cardiovascular mortality in a nonclinical population. The pathway by which this association occurs remains unclear, but further follow-up of our participants with cumulated numbers of deaths will allow examination of these issues in greater detail," wrote Dr. Kumari and her coinvestigators.
The authors reported that they have nothing to disclose.