Cortisol diurnal patterns, associations with depressive symptoms, and the impact of intervention in older adults: results using modern robust methods aimed at dealing with low power due to violations of standard assumptions

Depression, perceived social control, and hypothalamic-pituitary-adrenal axis function in African-American adults

OBJECTIVE

Social determinants may negatively affect health via Hypothalamic-Pituitary-Adrenal (HPA) axis dysfunction. The potential contribution of social determinants and related factors to HPA-axis functioning is important to study among African American adults, who are more likely to experience societal inequities and health disparities relative to other racial/ethnic groups. This study examined the relationship between depressive symptoms and perceived social control on HPA-axis functioning among African American adults.

METHOD

Participants (N = 107; Mage = 50, 79% female) were administered measures including the Center for Epidemiologic Studies-Depression and Informal (neighborhood) Social Control. Study procedures included the provision of 6 saliva samples for cortisol analysis (at wakeup, 30- and 90-min post-wakeup, 2:00 PM, 5:00 PM, and prebedtime). The relationship between depression and social control on the functioning of the HPA-axis were simultaneously examined within a 2-level hierarchical linear model.

RESULTS

Variability in the Cortisol Awakening Response (CAR) was accounted for by depressive symptomatology (p = .023) and perceived social control (p = .016), whereby greater depression was associated with a blunted CAR (less awakening cortisol production) and greater perceptions of neighborhood social control with a higher CAR.

CONCLUSIONS

Elevated depressive symptoms and low perceptions of neighborhood social control may serve as mechanisms that help to explain within-group variability in the functioning of stress physiology among African American adults. Findings enhance understanding of how social determinants may affect African Americans' health. (PsycINFO Database Record (c) 2020 APA, all rights reserved).

Physiological and Psychological Stress in Patients Living With a Left Ventricular Assist Device

Patients with a left ventricular assist device (LVAD) commonly experience psychological distress post-implantation, but physiological stress and differences by implant strategy remain unstudied. This study describes indicators of physiological (salivary cortisol, C-reactive protein, sleep quality) and psychological (perceived stress, depression, and fatigue) stress by implant strategy and examines relationships between stress and outcomes (quality of life [QOL] and functional status). Prospective, cross-sectional data were collected from patients ≥3 months post-LVAD implantation (n = 44), and descriptive statistics and logistic regression were used. The study sample was average age 57.7 ± 13 years, mostly male (73%), married (70.5%), and racially diverse. Median LVAD support was 18.2 months. Most had normal cortisol awakening response and fair sleep quality, with moderate psychological stress. There were no differences in stress by implant strategy. Normal cortisol awakening response was correlated with low depressive symptoms. Sleep quality and psychological stress were associated with QOL, whereas cortisol and C-reactive protein levels were associated with functional status. This is the first report of salivary biomarkers and stress in LVAD outpatients. Future research should examine physiological and psychological stress and consider potential clinical implications for stress measurement for tailored approaches to stress management in this population.

Cortisol, oxytocin, and quality of life in major depressive disorder

PURPOSE

Quality of life (QoL) is greatly impaired in major depressive disorder (MDD). These impairments are not fully accounted for by symptom severity, may persist beyond depressive episodes, and are a risk factor for poor outcomes. MDD is often associated with prominent neuroendocrine changes and increased risk of chronic disease. However, there is a lack of research examining whether biological factors are related to QoL in MDD. This research examined relationships between cortisol, oxytocin, symptom severity, and QoL in MDD.

METHODS

Sixty adults meeting DSM-5 criteria for MDD and 60 healthy controls provided morning plasma samples which were analysed for cortisol and oxytocin levels, and completed measures of QoL and psychopathology.

RESULTS

Participants with MDD had lower QoL than controls. Cortisol correlated negatively with overall QoL and all QoL domains. Oxytocin correlated positively with overall QoL, and Psychological and Social-Relationships domains. Additionally, cortisol levels were inversely related to psychological QoL, and oxytocin was positively related to social QoL, after controlling for symptom severity and demographic variables.

CONCLUSIONS

This study provides novel evidence linking neuroendocrine pathways to particular domains of QoL in MDD. The results indicate that activity of the hypothalamic-pituitary-adrenal axis is linked to poor psychological QoL, and that oxytocin is important to social QoL, independently of severity of psychopathology. Biopsychosocial approaches to QoL associated with mental health conditions may lead to greater understanding of the underlying mechanisms and to improved, tailored interventions.

Probability of bivariate superiority: A non-parametric common-language statistic for detecting bivariate relationships

Researchers often focus on bivariate normal correlation (r) to evaluate bivariate relationships. However, these techniques assume linearity and depend on parametric assumptions. We propose a new nonparametric statistical model that can be more intuitively understood than the conventional r: probability of bivariate superiority (PBS). Our development of B_p, the estimator of a PBS relationship, extends Dunlap's (1994) common-language transformation of r (CL_r) by providing a method to directly estimate PBS-the probability that when x is above (or below) the mean of all X, its paired y score will also be above (or below) the mean of all Y. Probability of superiority is an important form of bivariate relationship that until now could only be accurately estimated when data met the parametric assumptions for r. We specify the copula that forms the theoretical basis for PBS, provide an algorithm for estimating PBS from a sample, and describe the results of a Monte Carlo experiment that evaluated our algorithm across 448 data conditions. The PBS estimate, B_p, is robust to violations of parametric assumptions and offers a useful method for evaluating the significance of probability-of-superiority relationships in bivariate data. It is critical to note that B_p estimates a different form of bivariate relationship than does r. Our working examples show that a PBS effect can be significant in the absence of a significant correlation, and vice versa. In addition to utilizing the PBS model in future research, we suggest that this new statistical procedure be used to find theoretically important but previously overlooked effects from past studies.

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.

Use of Salivary Diurnal Cortisol as an Outcome Measure in Randomised Controlled Trials: a Systematic Review

Background

Dysregulation of the hypothalamic-pituitary-adrenal (HPA) axis is associated with diverse adverse health outcomes, making it an important therapeutic target. Measurement of the diurnal rhythm of cortisol secretion provides a window into this system. At present, no guidelines exist for the optimal use of this biomarker within randomised controlled trials (RCTs).

Purpose

The aim of this study is to describe the ways in which salivary diurnal cortisol has been measured within RCTs of health or behavioural interventions in adults.

Methods

Six electronic databases (up to May 21, 2015) were systematically searched for RCTs which used salivary diurnal cortisol as an outcome measure to evaluate health or behavioural interventions in adults. A narrative synthesis was undertaken of the findings in relation to salivary cortisol methodology and outcomes.

Results

From 78 studies that fulfilled the inclusion criteria, 30 included healthy participants (38.5 %), 27 included patients with physical disease (34.6 %) and 21 included patients with psychiatric disease (26.9 %). Psychological therapies were most commonly evaluated (n = 33, 42.3 %). There was substantial heterogeneity across studies in relation to saliva collection protocols and reported cortisol parameters. Only 39 studies (50 %) calculated a rhythm parameter such as the diurnal slope or the cortisol awakening response (CAR). Patterns of change in cortisol parameters were inconsistent both within and across studies and there was low agreement with clinical findings.

Conclusions

Salivary diurnal cortisol is measured inconsistently across RCTs, which is limiting the interpretation of findings within and across studies. This indicates a need for more validation work, along with consensus guidelines.

Electronic supplementary material

The online version of this article (doi:10.1007/s12160-015-9753-9) contains supplementary material, which is available to authorized users.

Daily cortisol activity, loneliness, and coping efficacy in late adolescence: A longitudinal study of the transition to college

Many late adolescents who transition to the college environment perceive changes in psychosocial stress. One such stressor, loneliness, has been associated with numerous health problems among adolescents and adults. The hypothalamic-pituitary-adrenal axis is one mechanism through which loneliness may affect health. Guided by a risk and resilience framework, the present study investigated the association between longitudinal changes in loneliness from high school to college and diurnal cortisol activity (waking levels, cortisol awakening response, diurnal slope) by sampling saliva intensively 5 times a day for 3 weekdays in a US sample of late adolescents in their first semester of college (N = 70; M_age = 18.49, SD = 0.38). The present study also explored how the link between loneliness and cortisol might depend on coping efficacy-one's belief in successfully coping with future stressors or novel situations. Results from hierarchical linear growth curve models demonstrated that an increase in loneliness across this contextual transition was associated with steeper cortisol slopes in college. Coping efficacy at baseline (in high school) significantly moderated the relation between changes in loneliness and diurnal slopes, such that late adolescents with low levels of coping efficacy who reported increased loneliness across the transition exhibited significantly flatter diurnal slopes in college. Higher levels of coping efficacy at baseline also significantly predicted lower waking cortisol levels during the first semester of college. These results suggest that coping efficacy may serve as a protective factor by contributing to regulation of daily physiological stress activity for late adolescents as they struggle with loneliness across the transition to college.