Objective: To determine if cynical hostility is associated with alterations in diurnal profiles of cortisol. Hostility has been linked to cardiovascular disease but the biological mechanisms mediating this association remain unknown.
Methods: Up to 18 measures of salivary cortisol taken over 3 days were obtained from each of 936 participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Cynical hostility was measured using an eight-item subscale of the Cook-Medley Hostility Scale. Cortisol profiles were modeled using regression spline models that incorporated random parameters for subject-specific effects. Models were adjusted for race, sex, age, socioeconomic position, and lifestyle factors. The association of cynical hostility with key features of the cortisol diurnal profile, both in the full sample and important subsamples, was examined.
Results: Waking cortisol levels as well as the extent of the morning surge in cortisol levels did not differ significantly across tertiles of cynical hostility. Respondents in the lowest tertile of cynical hostility experienced a 22% sharper decline in salivary cortisol (age- and sex-adjusted slope of -0.49 microg/dL per hour) than respondents in the highest tertile (-0.40 microg/dL per hour, p for difference = .0004). Intertertile differences in these parameters remained unaltered after further adjustment for potential confounders. This pattern of differences in cortisol diurnal profile tended to be related in a dose-response way to level of cynical hostility, and persisted in stratified analyses.
Conclusions: Cynical hostility is associated with the declining phase of the awakening cortisol response. The implications of this for cardiovascular and other health outcomes remain to be determined.