Individuals differ widely in cortisol output over the day, but the etiology of these individual differences remains poorly understood. Twin studies are useful for quantifying genetic and environmental influences on variation in cortisol output, lending insight into underlying influences on the components of Hypothalamic-Pituitary-Adrenal (HPA) axis functioning.
Salivary cortisol was assayed on 446 twin pairs (157 monozygotic, 289 dizygotic; ages 7–8). Parents helped youth collect saliva 30 min after waking, mid-afternoon, and 30 minutes prior to bedtime across 3 consecutive days. We used hierarchical linear modeling to extract predicted cortisol levels and to distinguish cortisol’s diurnal rhythm using a slopes-as-outcome piecewise growth curve model; two slopes captured the morning-to-afternoon and afternoon-to-evening rhythm, respectively. Separate genetic models were then fit to cortisol level at waking, mid-afternoon, and evening as well as the diurnal rhythm across morning-to-afternoon and afternoon-to-evening hours.
Three results from these analyses are striking. First, morning-to-afternoon cortisol level showed the highest additive genetic variance (heritability), consistent with prior research. Second, cortisol’s diurnal rhythm had an additive genetic component, particularly across the morning-to-afternoon hours. In contrast, additive genetic variation did not significantly contribute to variation in afternoon-to-evening slope. Third, the majority of variance in cortisol concentration was associated with shared family environments. In summary, both genetic and environmental factors influence cortisol’s circadian rhythm, and they do so differentially across the day.
HPA axis; cortisol; diurnal rhythm; twins; behavior genetics
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. The Multi-Ethnic Study of Atherosclerosis (MESA) 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 minutes post-awakening), early decline (30 minutes to 2 hours post-awakening), late decline (2 hours post-awakening to bedtime), and the corresponding areas under the curve (AUC). Body-mass-index (BMI) and waist circumference (WC) were used to estimate adiposity. 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, beta blockers, steroids, hormone replacement therapy and smoking status. No heterogeneities of effects were observed by gender, age, and race/ethnicity. Higher BMI and WC are associated with neuroendocrine dysregulation, which is present in a large population sample, and only partially explained by other covariates.
adiposity; hypothalamic-pituitary-adrenal (HPA) axis; salivary cortisol; diurnal cortisol; cortisol awakening response; epidemiology; obesity; body mass index; waist circumference; epidemiology
Maltreated foster children often exhibit alterations in diurnal hypothalamic-pituitary-adrenal (HPA) axis activity that are characterized by lower cortisol levels upon waking and smaller declines in morning-to-evening cortisol levels. Previous research has shown that this dysregulated pattern is associated with high caregiver stress levels over the course of foster care placements. In contrast, therapeutic interventions that emphasize consistent and responsive caregiving have been associated with more regulated cortisol rhythms. In this paper, two related issues were explored: whether placement changes (i.e., moving between foster homes or from a foster home to a permanent placement) were associated with more blunted daily cortisol rhythms and whether a caregiver-based intervention exerted a protective effect in this context. Because the intervention program has components specifically designed to prepare foster children for placement changes and to maintain consistent parenting techniques despite them, a prevention effect on HPA axis dysregulation during placement changes was hypothesized. The results of linear mixed modeling analyses showed that placement changes predicted dysregulation in cortisol rhythms in the regular foster care group but not in the intervention foster care group. These findings are discussed in terms of implications for child welfare policy and practice.
diurnal cortisol; dysregulation; foster care; intervention; preschool
The concept of allostasis suggests that greater cumulative stress burden can influence stress-responsive physiology. Dysregulation of allostatic mediators, including the hypothalamic-pituitary-adrenal (HPA) axis, is thought to precede many other signs of age-related pathology as the persistent burden of stressors accumulates over the individual's lifespan. We predicted that even in young adulthood, HPA regulation would differ between Blacks and Whites reflecting, in part, higher rates of stressor exposure and greater potential for stressors to “get under the skin”. We examined whether stressor exposure, including experiences with racism and discrimination, explained race differences in waking cortisol and the diurnal rhythm. We also examined whether HPA functioning was associated with mental health outcomes previously linked to cortisol. Salivary cortisol was assayed in 275 young adults (127 Blacks, 148 Whites, 19 to 22 years old), four times a day across 3 days. Hierarchical linear models revealed flatter slopes for Blacks, reflecting significantly lower waking and higher bedtime cortisol levels compared to Whites. Associations of HPA functioning with stressors were typically more robust for Whites such that more stress exposure created an HPA profile that resembled that of Black young adults. For Blacks, greater stressor exposure did not further impact HPA functioning, or, when significant, was often associated with higher cortisol levels. Across both races, flatter slopes generally indicated greater HPA dysregulation and were associated with poor mental health outcomes. These differential effects were more robust for Whites. These findings support an allostatic model in which social contextual factors influence normal biorhythms, even as early as young adulthood.
allostasis; cortisol; race differences; HPA axis
The evidence on whether there is work stress related dysregulation of the hypothalamic-pituitary-adrenal axis is equivocal. This study assessed the relation between work stress and diurnal cortisol rhythm in a large-scale occupational cohort, the Whitehall II study.
Work stress was assessed in two ways, using the job-demand-control (JDC) and the effort-reward-imbalance (ERI) models. Salivary cortisol samples were collected six times over a normal day in 2002–2004. The cortisol awakening response (CAR) and diurnal cortisol decline (slope) were calculated.
In this large occupational cohort (N = 2,126, mean age 57.1), modest differences in cortisol patterns were found for ERI models only, showing lower reward (β = −0.001, P-value = 0.04) and higher ERI (β = 0.002, P-value = 0.05) were related to a flatter slope in cortisol across the day. Meanwhile, moderate gender interactions were observed regarding CAR and JDC model.
We conclude that the associations of work stress with cortisol are modest, with associations apparent for ERI model rather than JDC model.
Age-associated alterations in hypothalamic–pituitary–adrenal (HPA) axis functioning may make individuals more susceptible to HPA dysregulation in the context of mood and anxiety disorders. Little to no research has been done to examine HPA axis function in generalized anxiety disorder (GAD), particularly in late-life GAD, the most prevalent anxiety disorder in the elderly. The study sample consisted of 71 GAD subjects and 40 nonanxious comparison subjects over 60 years of age. We examined the hypotheses that elderly individuals with GAD will have elevated salivary cortisol levels compared to nonanxious subjects, and that elevated cortisol levels in GAD will be associated with measures of symptom severity. We report that late-life GAD is characterized by elevated basal salivary cortisol levels, with higher peak cortisol levels and larger areas under the curve, compared to nonanxious subjects. Additionally, severity of GAD as measured by the GAD Severity Scale and the Penn State Worry Questionnaire are positively correlated with cortisol levels. These data demonstrate HPA axis dysfunction in late-life GAD and suggest the need for additional research on the influence of aging on HPA axis function in mood and anxiety disorders.
Cortisol; Generalized anxiety disorder; Elderly; Worry; HPA axis; Saliva
Childhood sexual abuse (CSA) has been associated with dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis in non-pregnant samples. However, it is not yet known whether CSA is associated with HPA dysregulation over pregnancy. In the present study we assessed whether maternal cortisol levels across pregnancy differed in women with CSA histories compared to women with histories of non-sexual child abuse (CA) and no abuse (NA).
135 pregnant mothers (CSA=30, CA=58, NA=47) provided salivary cortisol samples at wakeup, wake +30 minutes, and bedtime for 3 consecutive days at 1–3 time points over second and third trimester. Cortisol awakening responses and slopes were computed.
Women with CSA histories displayed increasing cortisol awakening response over pregnancy compared to women with CA and NA histories. Group differences were not observed for slope.
This is the first study to show that cortisol awakening responses increase over pregnancy in women with CSA histories compared to women with CA and NA histories.
child abuse; cortisol; cortisol awakening response; cortisol slope; pregnancy
Disruptions in hypothalamic-pituitary-adrenal regulation and immunity have been associated with posttraumatic stress disorder (PTSD). We examined the association of PTSD with diurnal rhythms in salivary cortisol in a convenience sample from a population-based study of male and female American Indians. Subjects with and without PTSD were identified from American Indians living on/near a Northern Plains reservation as part of a larger study. Over two days diurnal saliva samples were collected by staff at the University of Colorado Denver Clinical Research Center at waking, 30 minutes after waking, before lunch, and before dinner. Generalized estimating equations linear regression models investigated the influence of PTSD on cortisol over time. The association of a lifetime diagnosis of PTSD with salivary cortisol level was assessed in subjects with complete data (PTSD: n=27; no PTSD n=32) for age, gender, and alcohol consumption in the past month. Subject mean age was 44 years, and 71% were women. When stratified by gender, women with a lifetime diagnosis of PTSD had significantly higher mean cortisol levels throughout the day than women without PTSD (p = 0.01); but there was no significant association between PTSD and cortisol levels in men (p = 0.36). The cortisol awakening response – the difference in cortisol levels from waking to 30 minutes after waking – was not associated with PTSD in men or women. A lifetime diagnosis of PTSD may influence diurnal cortisol among American Indian women. These effects were independent of influences of current alcohol use/abuse. The unexpected elevation in cortisol in American Indian women with a lifetime diagnosis of PTSD may reflect acute anxiety associated with experiencing a number of novel tests in a strange location (e.g., cardiac imaging, medical and dental exams, etc.), or concurrent depression.
Health disparities; Northern Plains Indians; cortisol awakening response
Generalized Anxiety Disorder (GAD) is a common disorder in older adults which has been linked to hyperactivity of the Hypothalamic-Pituitary-Adrenal (HPA) axis in this age group. We examined whether treatment of GAD in older adults with a selective serotonin reuptake inhibitor (SSRI) corrects this HPA axis hyperactivity.
We examined adults aged 60 and above with GAD in a 12-week randomized controlled trial comparing the SSRI escitalopram to placebo. We collected salivary cortisol at six daily timepoints for two consecutive days to assess peak and total (area under the curve) cortisol, both at baseline and post-treatment.
Compared with placebo-treated subjects, SSRI-treated subjects had a significantly greater reduction in both peak and total cortisol. This reduction in cortisol was limited to subjects with elevated (above the median) baseline cortisol, in whom SSRI-treated subjects showed substantially greater reduction in cortisol than did placebo-treated subjects. Reductions in cortisol were associated with improvements in anxiety. Additionally, genetic variability at the serotonin transporter promoter predicted cortisol changes.
SSRI treatment of GAD in older adults reduces HPA axis hyperactivity. Further research should determine whether these treatment-attributable changes are sustained and beneficial.
anxiety; cortisol; aging; health; stress; antidepressant
Tourette syndrome (TS) is characterized by motor and vocal tics, which are often exacerbated by stress. The hypothalamic-pituitary-adrenocortical (HPA) axis, a major stress response system is thus of interest for understanding TS.
Diurnal cortisol rhythms were estimated in medication-free children 7-to-13 years with TS (N=20) and healthy age-matched controls (N=16). Salivary samples were collected on three consecutive days from the home. HPA responsivity was assessed by examining cortisol in response to a mock and real MRI scan.
The results of diurnal rhythmicity revealed a trend showing marginally lower evening cortisol for the TS group. By contrast, the TS group had higher cortisol levels in response to the stressor. There were strong, negative correlations between evening cortisol and tic severity as well as diurnal cortisol and anxiety.
The children with TS showed increased cortisol in response to the MRI environment, supporting a model of enhanced HPA responsivity. The lower evening cortisol may be the result of chronic daily stress. Alternatively, the negative associations between cortisol and reported anxiety and tics may reflect biologically-based anxiolytic properties of tic expression. Taken together, the results clearly implicate involvement of the HPA axis in the neuropathology of TS.
Tourette syndrome; cortisol; HPA axis; stress; anxiety; diurnal rhythm
Maternal stress during pregnancy is associated with negative maternal/child outcomes. One potential biomarker of the maternal stress response is cortisol, a product of activity of the hypothalamic-pituitary-adrenal axis. This study evaluated cortisol levels in hair throughout pregnancy as a marker of total cortisol release. Cortisol levels in hair have been shown to be easily quantifiable and may be representative of total cortisol release more than single saliva or serum measures. Hair cortisol provides a simple way to monitor total cortisol release over an extended period of time. Hair cortisol levels were determined from each trimester (15, 26 and 36 wks gestation) and 3 months postpartum. Hair cortisol levels were compared to diurnal salivary cortisol collected over 3 days (3 times/day) at 14, 18, 23, 29, and 34 wks gestational age and 6 wks postpartum from 21 pregnant women. Both salivary and hair cortisol levels rose during pregnancy as expected. Hair cortisol and diurnal salivary cortisol area under the curve with respect to ground (AUCg) were also correlated throughout pregnancy. Levels of cortisol in hair are a valid and useful tool to measure long-term cortisol activity. Hair cortisol avoids methodological problems associated with collection other cortisol measures such as plasma, urine, or saliva and is a reliable metric of HPA activity throughout pregnancy reflecting total cortisol release over an extended period.
hypothalamic pituitary adrenal axis; stress biomarkers; thrifty phenotype; early programming
High levels of cortisol, a sign of potential hypothalamic-pituitary-adrenal (HPA) axis dysregulation, have been associated with poor cognitive outcomes in older adults. Most cortisol research has focused on hippocampal-related abilities such as episodic memory; however, the presence of glucocorticoid receptors in the human prefrontal cortex suggests that cortisol regulation is likely to be associated with prefrontally-mediated executive function abilities. We hypothesized that elevated cortisol levels would be associated with poorer frontal-executive function in addition to episodic memory. We assessed cortisol from 15 saliva samples paralleling individual diurnal rhythms across three non-consecutive days in a group of 778 middle-aged twin men ages 51 to 60. Cognitive domains created from 24 standard measures included: general cognitive ability, verbal and visual-spatial ability, verbal and visual-spatial memory, short-term/immediate memory, working memory, executive function, verbal fluency, abstract reasoning, and psychomotor processing speed. Adjusting for general cognitive ability at age 20, age, race, and multiple health and lifestyle indicators, higher levels of average area-under-the-curve cortisol output across three days were significantly associated with poorer performance in three domains: executive (primarily set-shifting) measures, processing speed, and visual-spatial memory. In a 35-year longitudinal component of the study, we also found that general cognitive ability at age 20 was a significant predictor of midlife cortisol levels. These results possibly support the notion that glucocorticoid exposure is associated with cognitive functions that are mediated by frontal-striatal systems, and is not specific to hippocampal-dependent memory. The results also suggest that the direction of effect is complex.
Cortisol; HPA Axis; aging; cognition; cognitive aging; VETSA
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 1,002 participants in the Multi-Ethnic Study of Atherosclerosis. Diabetes was defined as a fasting blood glucose ≥126 mg/dL or medication use. Cortisol curve measures included awakening cortisol, cortisol awakening response (CAR), early decline, late decline, and cortisol area under the curve (AUC). Urinary catecholamines included epinephrine, norepinephrine, and dopamine.
Participants with diabetes had significantly lower CAR (β=−0.19; 95% CI: −0.34 to −0.04) than those without diabetes in multivariable models. While men with diabetes had a non-significant 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=0.02 for interaction) compared to those without diabetes. Men but not women with diabetes had significantly lower urinary catecholamines, compared to those without diabetes (p<0.05).
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.
diabetes; hypothalamic-pituitary-adrenal (HPA) axis; salivary cortisol; catecholamines; epidemiology
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.
HPA Axis; cortisol; inflammation; cytokines
The normal diurnal cortisol cycle has a peak in the morning, decreasing rapidly over the day, with low levels during the night, then rising rapidly again to the morning peak. A pattern of flatter daytime slopes has been associated with more rapid cancer progression in both animals and humans. We studied the relationship between the daytime slopes and other daytime cortisol responses to both pharmacological and psychosocial challenges of hypothalamic-pituitary-adrenal (HPA) axis function as well as DHEA in a sample of 99 women with metastatic breast cancer, in hopes of elucidating the dysregulatory process.
We found that the different components of HPA regulation: the daytime cortisol slope, the rise in cortisol from waking to 30 minutes later, and cortisol response to various challenges, including dexamethasone (DEX) suppression, corticotrophin releasing factor (CRF) activation, and the Trier Social Stress Task, were at best modestly associated. Escape from suppression stimulated by 1 mg of dexamethasone administered the night before was moderately but significantly associated with flatter daytime cortisol slopes (r=0..28 to .30 at different times of the post dexamethasone administration day, all p<.01) . Daytime cortisol slopes were also moderately but significant associated with the rise in cortisol from waking to 30 minutes after awakening (r=.29, p=.004, N=96), but not with waking cortisol level (r=−0.13, p=.19). However, we could not detect any association between daytime cortisol slope and activation of cortisol secretion by either CRF infusion or the Trier Social Stress Task. The CRF activation test (following 1.5 mg of dexamethasone to assure that the effect was due to exogenous CRF) produced ACTH levels that were correlated (r=0.66 p<.0001, N = 74) with serum cortisol levels, indicating adrenal responsiveness to ACTH stimulation. Daytime cortisol slopes were significantly correlated with the slope of DHEA (r=.21, p=.04, N=95). Our general findings suggest that flatter daytime cortisol slopes among metastatic breast cancer patients may be related to disrupted feedback inhibition rather than hypersensitivity in response to stimulation.
Cortisol; HPA; stress; dexamethasone; CRF; metastatic breast cancer
Maternal psychological functioning during pregnancy affects both maternal and fetal well-being. The hypothalamic-pituitary-adrenal (HPA) axis provides one mechanism through which maternal psychosocial factors may be transduced to the fetus. However, few studies have examined maternal psychological factors or birth outcomes in relation to the diurnal pattern of cortisol across the day. The current study examined maternal psychological well-being, parity status, and birth weight in relation to the maternal cortisol diurnal rhythm in a group of 98 low-risk pregnant women (51 primiparae). At 36 weeks gestation, participants completed both pregnancy-specific and general self-report measures of psychological functioning and provided saliva samples at 800, 1200, and 1600h on 2 consecutive working days for the assay of cortisol. The expected diurnal decline in salivary cortisol was observed. Higher trait anxiety was associated with a flatter afternoon decline for all mothers. For primiparae, steeper morning cortisol declines were associated with lower infant birth weight. The findings suggest that regulation of the HPA axis may differ by parity status with downstream implications for fetal growth and development.
cortisol diurnal rhythm; pregnancy; parity; fetus; anxiety; birth weight
This study evaluated whether measures of waking or diurnal cortisol secretion, or self-reported psychological disturbances differed among police officers with a Period3 (PER3) clock gene length polymorphism.
The cortisol awakening response was characterized via the area under the salivary cortisol curve with respect to the increase (AUCI) or total waking cortisol (AUCG). Diurnal cortisol measures included the slope of diurnal cortisol and the diurnal AUCG. Psychological disturbances were characterized using the Center for Epidemiologic Studies Depression Scale, Impact of Events Scale, and Life Events Scale.
Officers with a 4/5 or 5/5 genotype had higher awakening AUCG and greater diurnal cortisol AUCG levels compared to officers with the 4/4 genotype. Among those working more afternoon or night shifts, waking AUCI and AUCG were greater among officers with a 4/5 or 5/5 genotype compared to the 4/4 referents.
Cortisol secretion was modified among police officers with different PER3 VNTR clock gene variants.
PER3 VNTR; circadian; cortisol; shiftwork; police
Racial/ethnic minorities experience persistent health disparities due in part to their exposure to chronic SES and psychosocial risk. The hypothalamic-pituitary-adrenal axis and its hormonal end product, cortisol, are believed to mediate the associations between chronic stress and poor health. In this study, racial/ethnic differences in diurnal salivary cortisol rhythms in 179 preadolescent youths and the contributing roles of SES risk, psychosocial risk, perceived discrimination, harsh parenting, and parental monitoring were examined. The analyses revealed racial/ethnic differences in diurnal cortisol rhythms, with African Americans having significantly flatter morning-to-evening cortisol slopes than Caucasians and with Latinos having significantly lower evening cortisol levels than Caucasians. Greater psychosocial risk and less parental monitoring were associated with flatter cortisol slopes. Racial/ethnic differences on the cortisol measures persisted when controlling for SES, psychosocial risk, and parenting quality. The need to assess chronic risk across the lifespan and disentangle possible genetic from environmental contributors is discussed.
cortisol; race/ethnicity; preadolescent youths; psychosocial risk; parental monitoring
Despite observations of age-dependent sexual dimorphisms in hypothalamic-pituitary-adrenal (HPA) axis activity, the role of androgens in the regulation of HPA axis activity in men has not been examined. We assessed this role by performing CRH stimulation tests in ten men (ages 18–45) during gonadal suppression with leuprolide acetate and during testosterone addition to leuprolide. CRH-stimulated cortisol levels as well as peak cortisol and greatest cortisol excursion were significantly lower (p < .05, .005, and .01, respectively) during testosterone replacement compared with the induced hypogonadal condition (leuprolide plus placebo); cortisol area under the curve was lower at a trend level (p < .1). Paradoxically, CRH-stimulated ACTH was increased significantly during testosterone replacement (p < .05). The cortisol:ACTH ratio, a measure of adrenal sensitivity, was lower during testosterone replacement (p < .1). A mixed effects regression model showed that testosterone but not estradiol or CBG significantly contributed to the variance of cortisol. These data demonstrate that testosterone regulates CRH-stimulated HPA axis activity in men, with the divergent effects on ACTH and cortisol suggesting a peripheral (adrenal) locus for the suppressive effects on cortisol. Our results further demonstrate that the enhanced stimulated HPA axis activity previously described in young men compared with young women cannot be ascribed to an activational upregulation of the axis by testosterone.
testosterone; cortisol; HPA axis; ACTH; CRH; men
In attempts to understand the social determinants of health, strong associations have been found between measures of loneliness, physiological stress processes, and physical and mental health outcomes. Feelings of loneliness are hypothesized to have implications for physiological stress processes, including activity of the hypothalamic-pituitary-adrenal (HPA) axis. In a community sample of young adults, multilevel modeling was used to examine whether trait and state feelings of loneliness were related to changes in levels of the stress-sensitive hormone cortisol, and whether the associations between loneliness and cortisol were mediated or moderated by the presence of concurrent depression or high levels of chronic life stress. Results indicated that trait loneliness was associated with a flattening of the diurnal cortisol rhythm. In addition, both daily and momentary state variations in loneliness were related to cortisol. Prior-day feelings of loneliness were associated with an increased cortisol awakening response the next morning and momentary experiences of loneliness during the day were associated with momentary increases in cortisol among youth who also had high chronic interpersonal stress. Results were significant after covarying current depression, both chronic and momentary reports of stress, and medical and lifestyle covariates. This study expanded on prior work by investigating and revealing three different time-courses of association between loneliness and HPA axis activity in young adults: trait, daily and momentary.
loneliness; cortisol diurnal rhythms; HPA axis; young adults; momentary emotion; CAR
Prior research suggests that individuals with particular personality traits, like negative emotionality, are at greater risk for adverse health outcomes. Despite bivariate associations between negative emotionality, depressive symptoms and the hypothalamic pituitary adrenal axis (HPA axis), few studies have sought to understand the biological pathways through which negative emotionality, depressive symptomology and cortisol--one of the primary hormonal products of the HPA axis--are associated. The present study explored whether negative emotionality influenced cortisol dysregulation through current depressive symptomatology and whether negative emotionality served as a moderator of the relationship between depressive symptoms and cortisol. In the community-based Vietnam Era Twin Study of Aging, 783 male twins completed two days of cortisol saliva sampling in their natural environments. Three measures of cortisol were analyzed: waking levels, the cortisol awakening response, and the peak to bed slope. Depressive symptoms significantly mediated the associations between negative emotionality and the peak to bed slope. A 2-way interaction between depressive symptoms and negative emotionality was significant for the peak to bed slope and for waking levels of cortisol. Exploration of the interactions illustrated that depressive symptoms only affected cortisol slopes at average or high levels of negative emotionality and only affected waking levels at low levels of negative emotionality. Negative emotionality and depressive symptoms were not related to the cortisol awakening response. This is the first study to find indirect associations between negative emotionality and peak to bed cortisol slopes through depressive symptoms. These findings illustrate the complex interplay between personality characteristics, depressive symptoms and different indices of the cortisol diurnal rhythm.
cortisol; negative emotionality; depressive symptomatology
The hypothesis of fetal origins of adult disease has during the last decades received interest as an explanation of chronic, e.g. cardiovascular, disease in adulthood stemming from fetal environmental conditions. Early programming and enduring dysregulations of the hypothalamic-pituitary-adrenal (HPA axis), with cortisol as its end product, has been proposed as a possible mechanism by which birth weight influence later health status. However, the fetal origin of the adult cortisol regulation has been insufficiently studied. The present study aims to examine if body size at birth is related to circadian cortisol levels at 43 years.
Participants were drawn from a prospective cohort study (n = 752, 74.5%). Salivary cortisol samples were collected at four times during one day at 43 years, and information on birth size was collected retrospectively from delivery records. Information on body mass during adolescence and adulthood and on health behavior, medication and medical conditions at 43 years was collected prospectively by questionnaire and examined as potential confounders. Participants born preterm or < 2500 g were excluded from the main analyses.
Across the normal spectrum, size at birth (birth weight and ponderal index) was positively related to total (area under the curve, AUC) and bedtime cortisol levels in the total sample. Results were more consistent in men than in women. Descriptively, participants born preterm or < 2500 g also seemed to display elevated evening and total cortisol levels. No associations were found for birth length or for the cortisol awakening response (CAR).
These results are contradictory to previously reported negative associations between birth weight and adult cortisol levels, and thus tentatively question the assumption that only low birth weight predicts future physiological dysregulations.
This study examined links between diurnal patterns of the stress hormone, cortisol, and adolescents’ time in nine common daily activities.
During eight consecutive nightly telephone interviews, 28 youths (n = 12 girls), 10-18 years of age, reported their day’s activities. On four days, four saliva samples also were collected and assayed for cortisol. Multilevel models assessed within- and between-person associations between time in each activity and cortisol Area Under the Curve (AUC), cortisol awakening response (CAR), morning peak (30 minutes after wake up) and daily decline (morning peak to bedtime).
Links with AUC were found for most activities; significant associations with cortisol rhythms suggested that most effects were due to anticipation of the day’s activities. Specifically, on days when youths spent more time than usual on videogames and TV they had lower AUCs, with lower morning peaks. Youths who spent more time reading (within-person) and in computer activities (between-person) had higher AUCs, with stronger CARs (within-person). Youths who slept more had lower AUCs, with lower morning peaks on both the between- and within-person levels. Amounts of time spent in clubs, and for older adolescents, sports, were also linked to lower AUCs. Finally, youths who spent more time in school/schoolwork had lower AUCs, but on days when youths spent more time than usual in school, they had higher AUCs, stronger CARs, and steeper daily declines.
Beyond their known implications for psychological adjustment, youths’ everyday activities are linked to stress physiology.
stress; salivary cortisol; daily activities; time use
Millions of adults in the United States travel abruptly across time zones each year. Nevertheless, the impact of traveling over relatively short distances (across 3 or fewer time zones) on diurnal patterning of typical physiological response patterns has yet to be studied in a large, epidemiological sample.
The current research focuses on 764 middle-aged men comparing variations in diurnal cortisol regulation based on number of time zones traveled eastward or westward the day before.
Main Outcome Measure
Participants provided samples of salivary cortisol at waking, 30-min postwaking, 10 a.m., 3 p.m., and bedtime.
Eastward travel was associated with a steeper salivary cortisol awakening response ( p < .01) and lower peak (PEAK) levels of salivary cortisol the next morning ( p < .05). Westward travel was associated with lower peak levels of cortisol the next morning ( p < .05). Effect sizes for these differences ranged from Cohen’s d = .29 to .47. Differences were not present for 2 days in their home environment.
The results provide evidence that traveling across time zones is associated with diurnal cortisol regulation and should be studied further to understand the subsequent impacts on health and well-being in large national samples.
jet lag; cortisol diumal rhythms; travel
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 (rs) 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.
Adrenal gland volume; Cortisol awakening response; Cortisol diurnal curve; Dexamethasone suppression test; Reliability; Salivary cortisol