Association of salivary cortisol circadian pattern with cynical hostility: multi-ethnic study of atherosclerosis

Association between leukocyte telomere length and hostility in US army service members

Hostility is a common form of emotionally charged anger which can lead to maladaptive and unhealthy behaviors. Significant association between shortened telomeres and greater levels of hostility has been observed in civilian populations, but has not yet been comprehensively studied in military populations. Our study investigates the relationship between hostility, post-traumatic stress disorder (PTSD), and leukocyte telomere length (LTL) in a sample of United States Army Special Operations personnel (n = 474) who deployed to Iraq and/or Afghanistan as part of combat operations. Hostility was measured with five items from the Brief Symptom Inventory (BSI). PTSD was determined using the PTSD Checklist (PCL) total score. The LTL was assessed using quantitative polymerase chain reaction methods and regression analyses were conducted to determine the association of hostility and telomere length. PTSD subjects reported higher hostility scores compared with those without PTSD. Among the participants with PTSD, those with medium or high level of hostility had shorter LTL than those with low level hostility (P < 0.01). Stepwise regression indicated that hostility level and age, but not gender and PTSD, were negatively correlated with LTL. Univariate regression showed that total hostility score was negatively associated with LTL (CI= -0.06 to -0.002, Beta= -0.095, p < 0.039) as well as a significant correlation between LTL and hostility impulses (HI) (CI= -0.108 to -0.009, Beta= -0.106, p < 0.021) and hostility controlling (HC) (CI= -0.071 to -0.002, Beta= -0.095, p < 0.004). Multiple regression analyses revealed that, while HC has no significant association with LTL, HI was still negatively correlated with LTL (p = 0.021). Our data indicates that LTL is associated with HI levels. Prevention and treatment efforts designed to reduce hostility may help mitigate risk for LTL shortening, a process of cellular aging, and thus slow accelerated aged-related health outcomes.

Aggression as an independent entity even in psychosis - The role of cortisol

Aggression is a common entity in psychiatric disorders, particularly psychotic disorders. Glucocorticoid hypofunction has been linked to abnormal forms of aggressive behavior in various studies in a 'possibly causal' role. We hypothesise that aggression, even among those having psychosis is associated with glucocorticoid alterations similar to those who are aggressive but not psychotic. To our knowledge, this is the first study attempting to look at the cortisol functioning in relation to both aggression and psychosis. The present study included 80 participants divided into four groups depending upon presence or absence of aggression and psychosis. Morning cortisol, afternoon cortisol and their variability were measured using ELISA. The groups were compared on measures of aggression, psychosis, morning cortisol, afternoon cortisol and their variability using standard statistical instruments. The present study found lower levels of morning cortisol, afternoon cortisol and cortisol variability among the aggressive group (vs. non aggressive group) and among the diseased group (vs. non diseased group). The differences were most marked for cortisol variability which was related to both aggression and psychosis independently. There were statistically significant correlation between cortisol variability and aggression, which was retained even after controlling for psychosis. There was no significant correlation of cortisol variability with psychosis severity (after controlling for aggression score) or with age, gender or duration of psychosis. We conclude that aggression, even among patients with psychosis, is an independent entity characterized by lower levels of morning cortisol and cortisol variability. The etio-pathology may lie in some altered neuro-immune parameters executed by cortisol and psychosis as trigger.

Psychosocial functioning and the cortisol awakening response: Meta-analysis, P-curve analysis, and evaluation of the evidential value in existing studies

Cortisol levels rise immediately after awakening and peak approximately 30-45min thereafter. Psychosocial functioning influences this cortisol awakening response (CAR), but there is considerable heterogeneity in the literature. The current study used p-curve and meta-analysis on 709 findings from 212 studies to test the evidential value and estimate effect sizes of four sets of findings: those associating worse psychosocial functioning with higher or lower cortisol increase relative to the waking period (CARi) and to the output of the waking period (AUCw). All four sets of findings demonstrated evidential value. Psychosocial predictors explained 1%-3.6% of variance in CARi and AUCw responses. Based on these effect sizes, cross-sectional studies assessing CAR would need a minimum sample size of 617-783 to detect true effects with 80% power. Depression was linked to higher AUCw and posttraumatic stress to lower AUCw, whereas inconclusive results were obtained for predictor-specific effects on CARi. Suggestions for future CAR research are discussed.

A pilot randomized controlled trial of mindfulness-based stress reduction for caregivers of family members with dementia

OBJECTIVES

The majority of care for those with Alzheimer's disease and other age-related dementias is provided in the home by family members. To date, there is no consistently effective intervention for reducing the significant stress burden of many family caregivers. The present pilot randomized controlled trial tested the efficacy of an adapted, eight-week mindfulness-based stress reduction (MBSR) program, relative to a near structurally equivalent, standard social support (SS) control condition for reducing caregiver stress and enhancing the care giver-recipient relationship.

METHOD

Thirty-eight family caregivers were randomized to MBSR or SS, with measures of diurnal salivary cortisol, and perceived stress, mental health, experiential avoidance, caregiver burden, and relationship quality collected pre- and post-intervention and at three-month follow-up.

RESULTS

MBSR participants reported significantly lower levels of perceived stress and mood disturbance at post-intervention relative to SS participants. At three-month follow-up, participants in both treatment conditions reported improvements on several psychosocial outcomes. At follow-up, there were no condition differences on these outcomes, nor did MBSR and SS participants differ in diurnal cortisol response change over the course of the study.

CONCLUSION

Both MBSR and SS showed stress reduction effects, and MBSR showed no sustained neuroendocrine and psychosocial advantages over SS. The lack of treatment condition differences could be attributable to active ingredients in both interventions, and to population-specific and design factors.

Hostile attitudes and effortful coping in young adulthood predict cognition 25 years later

OBJECTIVE

We studied the relation of early-life (mean age 25 years) and mid-life (mean age 50 years) cognitive function to early measures of hostile attitudes and effortful coping.

METHODS

In 3,126 black and white men and women (born in 1955-1968) from the Coronary Artery Risk Development in Young Adults Study (CARDIA), we used linear regression to examine the association of hostile attitudes (Cook-Medley questionnaire) and effortful coping assessed at baseline (1985-1986) to cognitive ability measured in 1987 and to a composite cognitive Z score of tests of verbal memory, psychomotor speed, and executive function ascertained in midlife (2010-2011).

RESULTS

Baseline hostility and effortful coping were prospectively associated with lower cognitive function 25 years later, controlling for age, sex, race, education, long-term exposure to depression, discrimination, negative life events, and baseline cognitive ability. Compared to the lowest quartile, those in the highest quartile of hostility performed 0.21 SD units lower (95% confidence interval [CI] -0.39, -0.02). Those in the highest quartile of effortful coping performed 0.30 SD units lower (95% CI -0.48, -0.12) compared to those in the lowest quartile. Further adjustment for cumulative exposure to cardiovascular risk factors attenuated the association with the cognitive composite Z score for hostility.

CONCLUSIONS

Worse cognition in midlife was independently associated with 2 psychological characteristics measured in young adulthood. This suggests that interventions that promote positive social interactions may have a role in reducing risk of late-age cognitive impairment.

Relationships between inflammatory cytokine and cortisol responses in firefighters exposed to simulated wildfire suppression work and sleep restriction

The interplay between inflammatory and cortisol responses modulates an appropriate response to a stressor. Exposure to severe stressors, however, may alter the actions and relationships of these responses and contribute to negative health outcomes. Physical work and sleep restriction are two stressors faced by wildland firefighters, yet their influence on the relationship between inflammatory and cortisol responses is unknown. The aim of the present study was to quantify the relationship between the cytokine and cortisol responses to sleep restriction while performing simulated physical wildfire suppression work. Firefighters completed 3 days of simulated physical firefighting work separated by either an 8-h (Control condition; n = 18) or 4-h sleep (Sleep restriction condition; n = 17) opportunity on each of the two nights. Salivary cortisol and inflammatory cytokines (IL-6, IL-8, IL-1β, TNF-α, IL-4, and IL-10) were measured throughout each day. An increase in morning IL-6 was related to a rise (6.2%, P = 0.043) in evening cortisol among firefighters in the sleep restriction condition. Higher morning IL-6 levels were related to increased (5.3%, P = 0.048) daily cortisol levels, but this relationship was not different between conditions. Less pronounced relationships were demonstrated between TNF-α, IL-10, IL-4, and cortisol independent of the sleep opportunity, but relationships did not persist after adjusting for demographic factors and other cytokines. These findings quantify the relationship between cytokine and cortisol responses among wildland firefighters exposed to simulated occupational stressors. Potential disturbances to the IL-6 and cortisol relationship among sleep-restricted firefighters’ supports further investigations into the negative health effects related to possible imbalances between these systems.

Association of Sleep Duration and Quality With Alterations in the Hypothalamic-Pituitary Adrenocortical Axis: The Multi-Ethnic Study of Atherosclerosis (MESA)

CONTEXT

Short sleep duration and poor sleep quality are associated with cardiovascular outcomes. One mechanism proposed to explain this association is altered diurnal cortisol secretion.

OBJECTIVE

The objective of the study was to examine the associations of sleep duration and sleep quality with diurnal salivary cortisol levels.

DESIGN

This was a cross-sectional analysis using data from examination 5 (2010-2012) of the Multi-Ethnic Study of Atherosclerosis. Actigraphy-based measures of sleep duration and efficiency were collected over 7 days, and salivary cortisol samples were collected over 2 days from participants aged 54-93 years (n = 600 with analyzable data).

RESULTS

Shorter average sleep duration (<6 h/night) was associated with less pronounced late decline in cortisol [2.2% difference in slope; 95% confidence interval (CI) 0.8-3.7; P ≤ .01] and less pronounced wake-to-bed slope (2.2% difference; 95% CI 1.0-3.4; P ≤ .001) compared with longer sleep duration (≥6 h/night). Lower sleep efficiency (<85%) was associated with less pronounced early decline in cortisol (29.0% difference in slope; 95% CI 4.1-59.7; P < .05) compared with higher sleep efficiency (≥85%). Subjects reporting insomnia had a flatter cortisol awakening response (-16.1% difference in slope; 95% CI -34.6 to -0.1; P < .05) compared with those not reporting insomnia.

CONCLUSIONS

Shorter sleep duration, lower sleep efficiency, and insomnia are associated with alterations in diurnal cortisol levels consistent with changes in hypothalamic-pituitary-adrenal regulation.

Hostility and physiological responses to acute stress in people with type 2 diabetes

OBJECTIVE

Hostility is associated with cardiovascular mortality and morbidity, and one of the mechanisms may involve heightened reactivity to mental stress. However, little research has been conducted in populations at high risk for cardiovascular disease. The aim of the present study was to assess the relationship between hostility and acute stress responsivity in individuals with Type 2 diabetes.

METHODS

A total of 140 individuals (median age [standard deviation] 63.71 [7.00] years) with Type 2 diabetes took part in laboratory-based experimental stress testing. Systolic blood pressure, diastolic blood pressure, heart rate, plasma interleukin-6 (IL-6), and salivary cortisol were assessed at baseline, during two stress tasks, and 45 and 75 minutes later. Cynical hostility was assessed using the Cook Medley Cynical Hostility Scale.

RESULTS

Participants with greater hostility scores had heightened increases in IL-6 induced by the acute stress tasks (B = 0.082, p = .002), independent of age, sex, body mass index, smoking, household income, time of testing, medication, and baseline IL-6. Hostility was inversely associated with cortisol output poststress (B = -0.017, p = .002), independent of covariates. No associations between hostility and blood pressure or heart rate responses were observed.

CONCLUSIONS

Hostile individuals with Type 2 diabetes may be susceptible to stress-induced increases in inflammation. Further research is needed to understand if such changes increase the risk of cardiovascular disease in this population.

Variability and reliability of diurnal cortisol in younger and older adults: implications for design decisions

The extant research is inconclusive regarding the best sampling methods to construct reliable measures of between-person differences in derived parameters of diurnal cortisol, and no study provides such recommendations for detecting within-person changes. These studies determined how many days of sampling are necessary to assess between-person differences and within-person changes over multiple occasions in diurnal mean, diurnal slope, and area under the curve (AUC). Generalizability and decision analyses were conducted on diurnal salivary cortisol data from two separate longitudinal studies, one with younger adults (N=124) and one with older adults (N=148). In both studies, results indicated that 3 days of data collection provided the minimal level of reliability in mean cortisol to detect between-person differences; 4-8 days were necessary to reliably assess AUC, and 10 days for cortisol slope. Similarly, in order to reliably characterize within-person changes across occasions, at least 3 days of data collection were needed for mean cortisol and AUC and 5-8 days for slope. Results also indicated that only two samples per day, taken morning and evening, could faithfully reproduce the diurnal slope calculated from 3 or 4 samples (r=.97-.99). Instead of having participants provide many samples per day over the course of a few days, we recommend collecting fewer samples per day over more days.

Depressive Mood, Anger, and Daily Cortisol of Caregivers on High- and Low-Stress Days

OBJECTIVES

This study examines the association of daily cortisol with depressive mood and anger.

METHOD

Depressive mood, anger and 2 markers of cortisol, area under the curve (AUC), and cortisol awakening response (CAR) were examined for caregivers (N = 164) of individuals with dementia (IWDs) across 8 days, some of which IWDs attended an adult day service (ADS) program. Caregivers were primarily female (86.7%) with a mean age of 61.99. First, multilevel models were run with CAR and AUC each as separate covariates of anger and depressive mood. A second set of models examined contextual factors of caregivers (i.e., care-related stressors and amount of ADS use) were added to the models for anger and depressive mood (Model 2).

RESULTS

On days where caregivers had AUCs below their average they expressed higher anger scores. However in Model 2, anger was associated with more care-related stressors, but not ADS use or daily cortisol. Caregivers who on average had smaller CARs were more likely to be depressed. In Model 2, depressed mood was associated with more care-related stressors and a low average CAR.

DISCUSSION

We found that hypocortisol patterns, reflective of chronic stress experienced by caregivers, are associated with negative mood.

Associations of socioeconomic and psychosocial factors with urinary measures of cortisol and catecholamines in the Multi-Ethnic Study of Atherosclerosis (MESA)

BACKGROUND

Stress hormones have been hypothesized to contribute to the social patterning of cardiovascular disease but evidence of differences in hormone levels across social groups is scant.

PURPOSE

To examine the associations of socioeconomic and psychosocial factors with urinary levels of cortisol and catecholamines and determine whether these associations are modified by race/ethnicity.

METHODS

Measures of cortisol, epinephrine, norepinephrine and dopamine were obtained on 12-h overnight urine specimens from 942 White, African American and Hispanic participants in the Multi-Ethnic Study of Atherosclerosis (MESA). Linear regression was used to examine associations of income-wealth index, education, depression, anger, anxiety and chronic stress with the four hormones after adjustment for covariates.

RESULTS

Higher income-wealth index was associated with lower levels of urinary cortisol, epinephrine, norepinephrine and dopamine, after adjustment for age, sex, race/ethnicity, medication use, body mass index, smoking, and alcohol use. Education and psychosocial factors were not associated with urinary stress hormone levels in the full sample. However, there was some evidence of effect modification by race: SES factors were more strongly inversely associated with cortisol in African Americans than in other groups and anger was inversely associated with catecholamines in African Americans but not in the other groups.

CONCLUSIONS

Lower SES as measured by income-wealth index in a multi-ethnic sample is associated with higher levels of urinary cortisol and catecholamines. Heterogeneity in these associations by race/ethnicity warrants further exploration.

Relationship between the cortisol awakening response and other features of the diurnal cortisol rhythm: the Multi-Ethnic Study of Atherosclerosis

Cumulative cortisol burden is known to influence neuropsychiatric and metabolic disorders. To better understand the relationship between daily cortisol exposure and measures of the diurnal circadian cortisol rhythm, we examined the cross-sectional association of the cortisol awakening response (CAR) with wake-up cortisol, bedtime cortisol, diurnal slope, and total cortisol area under the curve (AUC). Up to 18 salivary cortisol samples were collected over 3 days from 935 White, Hispanic, and Black individuals (mean age 65 ± 9.8 years) in the Multi-Ethnic Study of Atherosclerosis. Outcome measures included awakening cortisol, CAR (awakening to 30 min post-awakening), early decline (30 min to 2h post-awakening), late decline (2h post-awakening to bedtime), and the corresponding AUCs. Total cortisol AUC was a summary measure of cumulative cortisol exposure. Higher CAR was associated with significantly lower wake-up cortisol (β=-0.56; 95% CI: -0.59 to -0.53) and a higher early decline AUC (β=0.38; 95% CI: 0.34-0.42) but was not associated with total cortisol AUC (β=0.04; 95% CI: -0.01 to 0.09), or other diurnal cortisol curve components following multivariable adjustment. Total cortisol AUC was significantly and positively associated with wake-up cortisol (β=0.36; 95% CI: 0.32-0.40), bedtime cortisol (β=0.61; 95% CI: 0.58-0.64), and other AUC measures, following multivariable adjustment. Associations were similar by sex, race/ethnicity, and age categories. We conclude that bedtime cortisol showed the strongest correlation with total cortisol AUC, suggesting it may be a marker of daily cortisol exposure.

Daytime trajectories of cortisol: demographic and socioeconomic differences--findings from the National Study of Daily Experiences

Cortisol's daytime rhythm is thought to be altered by aging and by exposure to chronic stress. However, measurement of an individual's usual cortisol rhythm is hampered by the effects of acute stressors, by differences between working days and weekends, by between-day variation in waking time and sleep duration, by variability in cortisol sampling times, and by possible variability in the timing of cortisol peak and nadir. Therefore, to determine differences in the usual daytime cortisol rhythm by age, socioeconomic status, and race/ethnicity, we measured salivary cortisol levels at four time-points, repeated over four days that included both weekdays and weekend days, in 1693 men and women from a national sample, and used three alternate growth curve specifications for the underlying cortisol rhythm (linear spline, quadratic spline, piece-wise linear-cubic) in order to minimize the impact of sample timing and other methodological issues. Model-predicted mean values of (and demographic and socioeconomic differences in) cortisol peak, nadir, and area under the curve (AUC) were nearly identical across model specifications. Older age and male gender were independently associated with higher cortisol peak, nadir, and AUC. Low education and minority race/ethnicity status were independently associated with lower cortisol peak and higher nadir, but were not associated with AUC. We also found significant cortisol peak and AUC associations with waking time, sleep duration, and workday vs. weekend day status, suggesting the importance of measuring these confounders and of collecting cortisol measurements over multiple days in research studies. We conclude that daytime cortisol levels are higher in older age and in men compared to women, and that the daytime cortisol rhythm is flatter (more blunted) in less privileged segments of society. Flattening of daytime cortisol rhythms may represent one mechanism by which social stressors lead to poor health outcomes.

A day-centered approach to modeling cortisol: diurnal cortisol profiles and their associations among U.S. adults

Diurnal cortisol is a marker of HPA-axis activity that may be one of the biological mechanisms linking stressors to age-related health declines. The current study identified day-centered profiles of diurnal cortisol among 1101 adults living in the United States. Participants took part in up to four consecutive days of salivary cortisol collection, assessed at waking, 30min post-waking, before lunch, and before bedtime. Growth mixture modeling with latent time basis was used to estimate common within-day trajectories of diurnal cortisol among 2894 cortisol days. The 3-class solution provided the best model fit, showing that the majority of study days (73%) were characterized by a Normative cortisol pattern, with a robust cortisol awakening response (CAR), a steep negative diurnal slope, coupled with low awakening and bedtime levels. Relative to this profile, diurnal cortisol on the remainder of days appeared either elevated throughout the day (20% of days) or flattened (7% of days). Relative to the normative trajectory, the elevated trajectory was distinguished by a higher morning cortisol level, whereas the flattened trajectory was characterized by a high bedtime level, with weaker CAR and diurnal slope parameters. Relative to the normative profile, elevated profile membership was associated with older age and cigarette smoking. Greater likelihood of the flattened cortisol pattern was observed among participants who were older, male, smoked cigarettes, used medications that are known to affect cortisol output, and reported poorer health. The current study demonstrates the value of a day-centered growth mixture modeling approach to the study of diurnal cortisol, showing that deviations from the classic robust rhythm of diurnal cortisol are associated with older age, male sex, use of medications previously shown to affect cortisol levels, poorer health behaviors, and poorer self-reported health.

Blunted nocturnal cortisol rise is associated with higher carotid artery intima-media thickness (CIMT) in overweight African American and Latino youth

BACKGROUND

Blunted diurnal cortisol variation has been associated with overt cardiovascular disease in adults. The relationship between the diurnal cortisol variation and subclinical atherosclerosis in youth has yet to be investigated. The objectives of this study were to (1) determine the relationship between overnight cortisol measures and CIMT in overweight and obese, African-American and Latino children; (2) assess ethnic differences in these relationships; and (3) explore whether overnight cortisol and CIMT relationships were independent of inflammatory markers, C-reactive protein (CRP), interleukin-6 (IL-6) and tumor necrosis factor-∝ (TNF-∝).

METHODS

One hundred fifty-six overweight and obese African-American and Latino children (ages 8-17, 86 M/70 F, 55 African-American/101 Latino) underwent measures of CIMT by B-mode ultrasound, nocturnal cortisol rise (NCR = salivary cortisol rise from 2200 h to awakening at 0530 h), cortisol awakening response (CAR = salivary cortisol from time of awakening to 30 min later), fasting serum cortisol and overnight urinary free cortisol.

RESULTS

Using linear regression, salivary cortisol(0530 h) and NCR were negatively associated with CIMT (β(standardized) = -0.215 and -0.220, p < 0.01) independent of age, height, percent body fat, ethnicity and systolic blood pressure. Nocturnal salivary cortisol(2200 h), morning serum cortisol, and overnight urinary free cortisol were not associated with CIMT. Using ANCOVA, participants with LOW NCR (NCR < 0.44 μg/dL, n = 52) had significantly greater CIMT than those with HIGH NCR (NCR ≥ 0.91 μg/dL, n = 52; 0.632 ± 0.008 vs. 0.603 ± 0.008 mm, p=0.01) after controlling for covariates. Ethnicity was independently associated with CIMT, whereby African-American children had greater CIMT than Latino children (-0.028 ± 0.009, p=0.006). The relationships between cortisol measures and CIMT did not differ between the two ethnic groups (all p(interaction) = 0.28-0.97). CRP, IL-6 and TNF-∝ were not associated with CIMT (p > 0.05). IL-6 was inversely related to NCR (r = -0.186, p = 0.03), but it did not explain the relationship between NCR and CIMT.

CONCLUSIONS

Salivary cortisol(0530 h) and NCR, but not CAR, nocturnal salivary cortisol(2200 h), morning serum cortisol or overnight urinary free cortisol were associated with CIMT, independent of relevant covariates, including inflammatory factors. A low awakening salivary cortisol or a blunted NCR may be related to increased atherosclerosis risk in overweight and obese minority youth. These findings support adult studies suggesting flattened daytime diurnal cortisol variation impacts cardiovascular disease risk.

Diurnal salivary cortisol is associated with body mass index and waist circumference: the Multiethnic Study of Atherosclerosis

OBJECTIVE

Neuroendocrine abnormalities, such as activation of the hypothalamic-pituitary-adrenal (HPA) axis, are associated with obesity; however, few large-scale population-based studies have examined HPA axis and markers of obesity. We examined the cross-sectional association of the cortisol awakening response (CAR) and diurnal salivary cortisol curve with obesity.

DESIGN AND METHODS

The Multiethnic Study of Atherosclerosis Stress Study includes 1,002 White, Hispanic, and Black men and women (mean age 65 ± 9.8 years) who collected up to 18 salivary cortisol samples over 3 days. Cortisol profiles were modeled using regression spline models that incorporated random parameters for subject-specific effects. Cortisol curve measures included awakening cortisol, CAR (awakening to 30-min postawakening), early decline (30 min to 2-h postawakening), late decline (2-h postawakening to bedtime), and the corresponding areas under the curve (AUC). Body mass index (BMI) and waist circumference (WC) were used to estimate adiposity.

RESULTS

For the entire cohort, both BMI and WC were negatively correlated with awakening cortisol (P < 0.05), AUC during awakening rise, and early decline and positively correlated to the early decline slope (P < 0.05) after adjustments for age, race/ethnicity, gender, diabetes status, socioeconomic status, β-blockers, steroids, hormone replacement therapy, and smoking status. No heterogeneities of effects were observed by gender, age, and race/ethnicity.

CONCLUSIONS

Higher BMI and WC are associated with neuroendocrine dysregulation, which is present in a large population sample, and only partially explained by other covariates.

Modeling the salivary cortisol profile in population research: the multi-ethnic study of atherosclerosis

In many studies, it has been hypothesized that stress and its biologic consequences may contribute to disparities in rates of cardiovascular disease. However, understanding of the most appropriate statistical methods to analyze biologic markers of stress, such as salivary cortisol, remains limited. The authors explore the utility of various statistical methods in modeling daily cortisol profiles in population-based studies. They demonstrate that the proposed methods allow additional insight into the cortisol profile compared with commonly used summaries of the profiles based on raw data. For instance, one can gain insights regarding the shape of the population average curve, characterize the types of individual-level departures from the average curve, and better understand the relation between covariates and attained cortisol levels or slopes at various points of the day, in addition to drawing inferences regarding common features of the cortisol profile, such as the cortisol awakening response and the area under the curve. The authors compare the inference and interpretations drawn from these methods and use data collected as part of the Multi-Ethnic Study of Atherosclerosis to illustrate them.

Do negative emotional factors have independent associations with excess adiposity?

OBJECTIVE

Taken in isolation, depression, anxiety, and hostility/anger have been shown to predict obesity. It is unknown whether these negative emotional factors are associated with adiposity, independently of each other. The objective of this review was to determine whether negative emotional factors have independent associations with adiposity.

METHODS

We searched for observational studies examining adiposity and two or more negative emotional factors. Studies which examined a negative emotional factor using analyses which controlled for other emotional factor(s) were selected for the review.

RESULTS

Three prospective and 11 cross-sectional studies met our inclusion/exclusion criteria. Of these investigations, 64% indicated that depression had positive associations with adiposity, independent of anxiety or hostility, and 56% indicated that anxiety had independent associations with adiposity. Only 33% of studies found independent associations for hostility and adiposity; however, far fewer studies were available.

CONCLUSION

Depression and anxiety have independent associations with excess adiposity when controlling for other emotional factors. Additional studies are needed to determine whether hostility/anger is independently associated with excess adiposity. These results have implications for the design of effective obesity prevention programs.

Neighborhood-level stressors, social support, and diurnal patterns of cortisol: the Chicago Community Adult Health Study

Neighborhood disadvantage has consistently been linked to increased rates of morbidity and mortality, but the mechanisms through which neighborhood environments may get "under the skin" remain largely unknown. Differential exposure to chronic environmental stressors has been identified as a potential pathway linking neighborhood disadvantage and poor health, particularly through the dysregulation of stress-related biological pathways such as cortisol secretion, but the majority of existing observational studies on stress and neuroendocrine functioning have focused exclusively on individual-level stressors and psychosocial characteristics. This paper aims to fill that gap by examining the association between features of the neighborhood environment and the diurnal cortisol patterns of 308 individuals from Chicago, Illinois, USA. We found that respondents in neighborhoods with high levels of perceived and observed stressors or low levels of social support experienced a flatter rate of cortisol decline throughout the day. In addition, overall mean cortisol levels were found to be lower in higher stress, lower support neighborhoods. This study adds to the growing evidence of hypocortisolism among chronically stressed adult populations and suggests hypocortisolism rather than hypercortisolism as a potential mechanism linking social disadvantage to poor health.

Associations of salivary cortisol levels with inflammatory markers: the Multi-Ethnic Study of Atherosclerosis

Socioeconomic and psychosocial factors have been found to be associated with systemic inflammation. Although stress is often proposed as a contributor to these associations, no population studies have investigated the links between inflammation and biomarkers of stress. The current study examines associations between daily cortisol profiles and inflammatory markers interleukin-6 (IL-6), interleukin-10 (IL-10), and tumor necrosis factor (TNF-a) in a population-based sample of 869 adults with repeat measures of cortisol over multiple days. Persons with higher levels of IL-6 had a less pronounced cortisol awakening response, a less steep daily decline, and higher cortisol area under the curve for the day with associations persisting after controls for risk factors and other cytokines. Persons with higher levels of TNF-a had lower cortisol levels upon waking, and flatter daily decline, although associations with decline were attenuated when controlling for inflammatory risk factors. Higher levels of IL-10 were associated with marginally flatter daily cortisol decline (p<.10). This study is the first to identify associations of basal cortisol activity and inflammatory markers in a population based sample. Findings are consistent with the possibility that HPA axis activity may mediate associations between psychosocial stressors and inflammatory processes. Additional prospective data are necessary to clarify the directionality of associations between cortisol and inflammatory markers.

Diurnal salivary cortisol and urinary catecholamines are associated with diabetes mellitus: the Multi-Ethnic Study of Atherosclerosis

The objective was to examine the cross-sectional association of diurnal salivary cortisol curve components and urinary catecholamines with diabetes status. Up to 18 salivary cortisol samples over 3 days and overnight urinary catecholamines were collected from 1002 participants in the Multi-Ethnic Study of Atherosclerosis. Diabetes was defined as a fasting blood glucose of at least 126 mg/dL or medication use. Cortisol curve measures included awakening cortisol, cortisol awakening response, early decline, late decline, and cortisol area under the curve (AUC). Urinary catecholamines included epinephrine, norepinephrine, and dopamine. Participants with diabetes had significantly lower cortisol awakening response (β = -0.19; 95% confidence interval [CI], -0.34 to -0.04) than those without diabetes in multivariable models. Whereas men with diabetes had a nonsignificant trend toward lower total AUC (β = -1.56; 95% CI, -3.93 to 0.80), women with diabetes had significantly higher total AUC (β = 2.62; 95% CI, 0.72 to 4.51) (P = .02 for interaction) compared with those without diabetes. Men but not women with diabetes had significantly lower urinary catecholamines compared with those without diabetes (P < .05). Diabetes is associated with neuroendocrine dysregulation, which may differ by sex. Further studies are needed to determine the role of the neuroendocrine system in the pathophysiology of diabetes.

Salivary cortisol in ambulatory assessment--some dos, some don'ts, and some open questions

The impact of stress on health and disease is an important research topic in psychosomatic medicine. Because research on hypothalamic-pituitary-adrenal (HPA) axis regulation under controlled laboratory studies lacks ecological validity, it needs to be complemented by a research program that includes momentary ambulatory assessment. The measurement of salivary cortisol offers the possibility to trace the free steroid hormone concentrations in ambulant settings. Therefore, in this article, we first discuss the role of salivary cortisol in ambulatory monitoring. We start with a brief description of HPA axis regulation, and we then consider cortisol assessments in other organic materials, followed by a presentation of common salivary markers of HPA axis regulation suitable for ambulatory assessment. We further provide an overview on assessment designs and sources of variability within and between subjects (intervening variables), acknowledge the issue of (non)compliance, and address statistical aspects. We further give an overview of associations with psychosocial and health-related variables relevant for ambulatory assessment. Finally, we deal with preanalytical aspects of laboratory salivary cortisol analysis. The relative simplicity of salivary cortisol assessment protocols may lead to an overoptimistic view of the robustness of this method. We thus discuss several important issues related to the collection and storage of saliva samples and present empirical data on the stability of salivary cortisol measurements over time.

Social strain and cortisol regulation in midlife in the US

Chronic stress has been implicated in a variety of adverse health outcomes, from compromised immunity to cardiovascular disease to cognitive decline. The hypothalamic pituitary adrenal (HPA) axis has been postulated to play the primary biological role in translating chronic stress into ill health. Stressful stimuli activate the HPA-axis and cause an increase in circulating levels of cortisol. Frequent and long-lasting activation of the HPA-axis, as occurs in recurrently stressful environments, can in the long run compromise HPA-axis functioning and ultimately affect health. Negative social interactions with family and friends may be a significant source of stress in daily life, constituting the type of recurrently stressful environment that could lead to compromised HPA functioning and altered diurnal cortisol rhythms. We use data from two waves (1995 and 2004-2005) of the Midlife in the U.S. (MIDUS) study and from the National Study of Daily Experiences (NSDE) and piecewise growth curve models to investigate relationships between histories of social strain and patterns of diurnal cortisol rhythms. We find that reported levels of social strain were significantly associated with their diurnal cortisol rhythm. These effects were more pronounced for individuals with a history of greater reported strain across a ten-year period.

Associations of salivary cortisol levels with metabolic syndrome and its components: the multi-ethnic study of atherosclerosis

CONTEXT

Prior research has identified associations between social-environmental factors and metabolic syndrome (MetS) components. The physiological mechanisms underlying these associations are not fully understood, but alterations in activity of the hypothalamic-pituitary-adrenal axis, a stress-responsive biological system, have been hypothesized to play a role.

OBJECTIVE

The aim of the study was to determine whether MetS diagnosis and specific clusters of MetS components (waist circumference, high-density lipoproteins, glucose, and blood pressure) are associated with cortisol levels.

DESIGN AND SETTING

We conducted cross-sectional analyses of data from the Multi-Ethnic Study of Atherosclerosis (MESA) study in the general community.

PATIENTS OR OTHER PARTICIPANTS

We studied a population-based sample of 726 adults (ages 48 to 89 yr) who do not have clinical diabetes.

INTERVENTION(S)

There were no interventions.

MAIN OUTCOME MEASURE(S)

Cortisol awakening response, cortisol decline across the waking day, and total cortisol output were analyzed (using 18 timed measures of salivary cortisol over 3 d).

RESULTS

Overall, we found little evidence that the presence of MetS or its components is related to cortisol output or patterns. Contrary to expectation, the presence of MetS was associated with lower rather than higher area under the curve, and no consistent pattern was observed when MetS components or subsets of components were examined in relation to cortisol.

CONCLUSIONS

Our findings do not support the hypothesis that differences in level or diurnal pattern of salivary cortisol output are associated with MetS among persons without clinical diabetes.

Reliability of hypothalamic-pituitary-adrenal axis assessment methods for use in population-based studies

Population-based studies have been hampered in exploring hypothalamic-pituitary-adrenal axis (HPA) activity as a potential explanatory link between stress-related and metabolic disorders due to their lack of incorporation of reliable measures of chronic cortisol exposure. The purpose of this review is to summarize current literature on the reliability of HPA axis measures and to discuss the feasibility of performing them in population-based studies. We identified articles through PubMed using search terms related to cortisol, HPA axis, adrenal imaging, and reliability. The diurnal salivary cortisol curve (generated from multiple salivary samples from awakening to midnight) and 11 p.m. salivary cortisol had the highest between-visit reliabilities (r = 0.63-0.84 and 0.78, respectively). The cortisol awakening response and dexamethasone-suppressed cortisol had the next highest between-visit reliabilities (r = 0.33-0.67 and 0.42-0.66, respectively). Based on our own data, the inter-reader reliability (r(s)) of adrenal gland volume from non-contrast CT was 0.67-0.71 for the left and 0.47-0.70 for the right adrenal glands. While a single 8 a.m. salivary cortisol is one of the easiest measures to perform, it had the lowest between-visit reliability (R = 0.18-0.47). Based on the current literature, use of sampling multiple salivary cortisol measures across the diurnal curve (with awakening cortisol), dexamethasone-suppressed cortisol, and adrenal gland volume are measures of HPA axis tone with similar between-visit reliabilities which likely reflect chronic cortisol burden and are feasible to perform in population-based studies.

Circadian rhythm of cortisol and neighborhood characteristics in a population-based sample: the Multi-Ethnic Study of Atherosclerosis

Although stress is often hypothesized to contribute to the effects of neighborhoods on health, very few studies have investigated associations of neighborhood characteristics with stress biomarkers. This study helps address the gap in the literature by examining whether neighborhood characteristics are associated with cortisol profiles. Analyses were based on data from the Multi-Ethnic Study of Atherosclerosis Stress study, which collected multiple measures of salivary cortisol over three days on a population based sample of approximately 800 adults. Multilevel models with splines were used to examine associations of cortisol levels with neighborhood poverty, violence, disorder, and social cohesion. Neighborhood violence was significantly associated with lower cortisol values at wakeup and with a slower decline in cortisol over the earlier part of the day, after sociodemographic controls. Associations were weaker and less consistent for neighborhood poverty, social cohesion, and disorder. Results revealed suggestive, though limited, evidence linking neighborhood contexts to cortisol circadian rhythms.

Nervous temperament in infant monkeys is associated with reduced sensitivity of leukocytes to cortisol's influence on trafficking

There is growing evidence that temperament/personality factors are associated with immune function and health-related outcomes. Neuroticism, in particular, is a risk-factor for several diseases, many with a strong inflammatory component. We propose that neuroticism (or nervous temperament in monkeys) is related to dysregulation of immune function by glucocorticoids. The present study tested the hypothesis that animals with a nervous temperament would show no relationship between cortisol concentrations and leukocyte numbers in peripheral blood (an easily obtainable measure of glucocorticoid-mediated immune function), while animals low on this factor would show expected relationships. Infant rhesus monkeys (n=1507) experienced a standardized testing procedure involving blood sampling, behavioral tests, and temperament ratings. Results confirmed the hypothesis: low-nervous animals showed the expected positive relationship between cortisol levels and neutrophil numbers, while high-nervous animals showed no relationship. High-nervous animals also showed elevated cortisol concentrations at most sample points, and responded to a human challenge with more negative emotional behavior. These data suggest that individuals with a nervous temperament show evidence of glucocorticoid desensitization of immune cells. Differences with other studies, including the specific types of leukocytes that are affected, are discussed, and implications for disease processes are suggested.

Salivary cortisol in a middle-aged community sample: results from 990 men and women of the KORA-F3 Augsburg study

OBJECTIVE

Analysis of salivary cortisol concentrations and derived indices is increasingly used in clinical and scientific medicine. However, comprehensive data on these parameters in the general population are scarce. The aim of this study was to evaluate the concentrations of salivary cortisol in a large middle-aged community sample and to identify major factors associated with altered hormone levels.

DESIGN

We conducted a cross-sectional study within the Cooperative Health Research in the Region of Augsburg (KORA)-F3 study. A total of 1484 participants aged 50-69 years (52% women) had agreed to provide four saliva samples during a regular weekday.

METHODS

We measured salivary cortisol concentrations at wake-up (F0), (1/2) h (F(1/2)), 8 h (F8), and 14 h (F14) after waking. We calculated cortisol awakening response (CAR), slope, and area under the curve (AUC(G)) of the circadian cortisol secretion. Sociodemographic and clinical characteristics were evaluated by interview and questionnaires, sampling conditions by protocol. In total, 1208 participants returned saliva samples, exclusion criteria left 990 subjects for final analyses.

RESULTS

Salivary cortisol levels were (means+/-s.d.) F0=13.7+/-7.6, F(1/2)=20.5+/-9.8, F8=5.4+/-3.3, and F14=2.0+/-1.8 nmol/l. Earlier sampling times were associated with higher CAR and smaller slope. Cortisol secretion was also influenced by gender and smoking habits. Higher perceived social support was associated with lower AUC(G) and smaller slope.

CONCLUSIONS

We provide data on salivary cortisol concentrations in a large middle-aged community sample. Gender, sampling time, smoking habits, and perceived social support appeared as determinants of cortisol secretion.

Cross-sectional and longitudinal associations of neighborhood characteristics with inflammatory markers: findings from the multi-ethnic study of atherosclerosis

We investigated cross-sectional associations of neighborhood deprivation, problems, safety, and cohesion with circulating levels of fibrinogen, interleukin-6, and C-reactive protein (n = 5370) and longitudinal associations with changes in IL-6 over a 3-4 year period (n = 946). In cross-sectional analyses, higher levels of neighborhood deprivation and problems were associated with higher levels of all three inflammatory markers, whereas higher levels of safety were associated with lower levels. Fibrinogen remained associated with all neighborhood characteristics except cohesion and IL-6 remained associated with safety after adjustment for race and SES. In longitudinal analyses, higher levels of neighborhood deprivation and problems, and lower levels of safety were associated with greater longitudinal increases in IL-6 after adjustment for age, sex, race, and SES. These findings were not substantially modified by further risk factor adjustment. Although findings regarding different inflammatory markers were mixed, the longitudinal results that are less limited by race confounding suggest that inflammatory pathways may contribute to neighborhood differences in cardiovascular disease risk.

Socioeconomic and race/ethnic differences in daily salivary cortisol profiles: the multi-ethnic study of atherosclerosis

It has often been hypothesized that stress and its biological consequences mediate the relationship between low socioeconomic status (SES) or minority status and poor cardiovascular disease outcomes. The objective of this study was to determine if daily cortisol patterns, a biomarker of the stress response, differ by race/ethnicity and socioeconomic status. Data were collected from 935 Black, White and Hispanic adults age 48-90 years old. Salivary cortisol samples were collected six times per day over 3 days: at awakening, 30min later, at 1000h, noon, 1800h and at bedtime. Blacks and Hispanics had lower levels of wake-up cortisol and less steep early declines, while Blacks had flatter and Hispanics steeper late day declines relative to Whites. Similarly the low socioeconomic status group also had lower levels of wake-up cortisol and less steep decline during the early part of the day. These patterns remained after adjustment for health behaviors and psychosocial factors. This study finds an association between salivary cortisol and race/ethnicity and SES in a multi-ethnic study population. Further work is needed to determine the health consequences of these differences.