Conscientiousness, hair cortisol concentration, and health behaviour in older men and women

Hair cortisol levels are associated with overweight and obesity in the ELSA-Brasil cohort

Introduction

Hair cortisol level has recently been identified as a promising marker for detecting long-term cortisol levels and a marker of hypothalamic-pituitary-adrenal cortex (HPA) axis activity. However, research on the association between obesity and an altered cortisol metabolism remains controversial.

Objective

This study aimed to investigate the relationship between hair cortisol levels and overweight and obesity in participants from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil).

Methods

This was a cross-sectional study involving 2,499 participants from the second follow-up (visit 3, 2017-2019) attending research centers in Rio de Janeiro and Rio Grande do Sul states. Hair samples were collected, and cortisol levels were analyzed using enzyme-linked immunosorbent assay (ELISA) kits. Cortisol levels were classified as low (< 40 pg/mg), medium (40-128 pg/mg), or high (> 128 pg/mg). The participants were classified as eutrophic, overweight, or obese according to their weight (kg) and height (m2). Odds ratios (ORs) with 95% confidence intervals (95%CI) were estimated.

Results

Of the 2499 individuals, 30% had eutrophic weight, 40% were overweight, and 30% were obese. Notably, cortisol levels gradually increased with increasing body weight. Among participants with high hair cortisol levels, 41.2% were classified as overweight and 34.2% as obese. Multinomial logistic regression analysis indicated that participants with high cortisol levels were 43% (OR =1.43; 95%CI: 1.02-2.03) more likely to be overweight and 72% (OR =1.72; 95%CI:1.20-2.47) more likely to be obese than participants with low hair cortisol levels. After adjustment for all covariates, high cortisol levels remained associated with obesity (OR = 1.54; 95%CI:1.02-2.31) and overweight (OR =1.33; 95%CI:0.91-1.94).

Conclusion

In the ELSA-Brazil cohort, hair stress were positively associated with overweight and obesity. These results underscore the importance of considering stress and cortisol as potential factors in obesity prevention and intervention efforts, and highlight a novel aspect of the complex relationship between stress and obesity in the Brazilian population.

Association of personality facets and cognition in the Lifelines population-based cohort study

BACKGROUND

Personality traits have been associated with cognitive functioning and risk of cognitive decline. Fewer studies have investigated how personality facets are associated with cognition in large cohorts with a prospective design.

METHODS

The association between eight personality facets and cognition (speed measures reflecting psychomotor speed and visual attention; hit rate measures reflecting visual learning and working memory) was analyzed in middle-aged adults from the Lifelines cohort (N = 79911; age 43 ± 11 years).

RESULTS

High hostility, high vulnerability, low excitement seeking, and low competence were associated with worse cognitive performance on all tasks. Impulsivity-related facets had weak and differential associations, with self-discipline negatively associated with accuracy and deliberation negatively associated with speed. These associations remained largely unchanged when accounting for lifestyle factors (smoking, alcohol consumption, physical activity). The associations with cognition were stronger in older people for impulsiveness, deliberation, and hostility, while stronger in younger people for excitement seeking, self-discipline, and vulnerability.

CONCLUSION

In a large population-based sample with a broad age range, the associations of personality facets with cognitive functioning had small effect sizes, were independent of lifestyle factors, and varied with age and among facets within the same personality domain. These findings highlight the importance of developmental stages and facet-level research in personality-cognition associations.

Personality traits and health-related behaviors in medical students facing a stressful event

Background

It is believed that personality traits have an impact on the propensity to change and maintain favorable lifestyle habits. This issue has been raised by multiple studies, however, none of them appeared to focus on population under severe psychological stress. The aim of the present study was to investigate the link between personality traits and health-related behaviors and measures such as dietary intake of specific food products, physical activity, body-mass index and the use of cigarettes in medical students facing a stressful event.

Methods

The study included a cohort of third-year medical students from the Medical University of Lodz, Poland, facing a stressful subject exam during the first COVID-19-related lockdown. At baseline, personality traits were evaluated with the use of the Polish version of the Big Five Inventory-Short questionnaire. Then, consumption of selected food products was monitored with the use of seven-day electronic dietary record. Also, some other health-related data was collected (body-mass index, physical activity and the use of cigarettes). General Linear Modeling techniques, logistic regression and exploratory factor analysis were applied to analyze the data.

Results

Four hundred and forty-four students completed the study. A two-factor pattern of food consumption was discovered by the exploratory factor analysis in the study group (34% of the variance explained). Higher conscientiousness, but not the other personality traits, was found to be significantly associated with generally healthier lifestyle manifested by higher consumption of vegetables, wholegrain products, fruits and nuts (adjusted beta 0.16, 95%CI 0.06 to 0.26, pη2 = 2.3%, p = 0.0015) and lower cigarette smoking (adjusted odds ratio 0.84, 95%CI 0.75 to 0.94, p = 0.0020), but insignificantly with physical activity and body-mass index.

Conclusion

Severely stressed medical students expressing high conscientiousness tend to present healthier behaviors. Therefore, interventions aimed at improving lifestyle habits in students with low conscientiousness might be useful.

Personality traits associated with Alcohol Dependence Syndrome and its relapse

Background

Course of Alcohol Dependence Syndrome (ADS) is studded with multiple relapses. Personality factors are implicated as one of the influencing factors in the course of this disorder. Keeping in view of scarcity of Indian data available, the study was planned with the aim to find Personality traits more commonly associated with ADS patients, and identify specific traits, associated with relapses of ADS.

Method

With sample size of 100 consecutive cases and 100 controls, socio-demographic data was collected. Alcohol Use Disorder Identification Test (AUDIT) and Severity of Alcohol Use Disorder Test (SAD-Q) were administered to each of these patient. Personality dimensions were assessed with NEO-five factor inventory (NEO-FFI) (Costa and McCrae), for both groups and further compared for differences in the dimensions in each of its subscale.

Results

The NEO scores, showed statistically significant difference with Cases having higher scores in Neuroticism and control group in Openness and Conscientiousness. Neuroticism linked to higher scores of AUDIT and SADQ and also associated with relapses. Other traits also showed statistically significant association which are discussed.

Conclusion

As new factors are being explored for effective management, routine personality profiling is easily accomplished and can give delightful insight into focused and designed management plan.

The Relationship between Conscientiousness and Well-Being among Chinese Undergraduate Students: A Cross-Lagged Study

Chinese culture attaches great importance to the education and cultivation of youth conscientiousness, however in the context of Chinese culture, little is known about the relationship between conscientiousness and mental and physical health. The present study aimed to investigate whether there is a reciprocal relationship between conscientiousness and well-being (subjective and physical well-being) among Chinese undergraduate students. A series of self-reported questionnaires were administered to 365 undergraduate students in 2 waves, separated by 1 year. Cross-lagged regression analyses were applied to examine the reciprocal relationships. Results indicated that conscientiousness positively predicted subsequent levels of positive affect and life satisfaction, while negatively predicted subsequent levels of negative affect and physical symptoms, controlling for the effects of gender, age, body-mass index, socioeconomic status, and the prior level of conscientiousness. Whereas, positive and negative affect, life satisfaction, and physical symptoms did not significantly predict subsequent levels of conscientiousness. This study suggests that conscientiousness is a robust and prospective predictor of subjective and physical well-being. The reciprocal relationship between conscientiousness and well-being was not confirmed in the current sample of Chinese undergraduate students.

Five-Factor Model Personality Traits and 24-hour Urinary Cortisol in the Baltimore Longitudinal Study of Aging

Stress is implicated in models of personality and health as a mechanism that explains why traits like conscientiousness and neuroticism are associated with long-term health outcomes. Evidence for an association between personality and cortisol, a biological marker of stress, however, has been inconsistent. This study examined the association between Five-Factor Model personality traits and 24-h urinary cortisol (operationalised as a ratio of urinary free cortisol to creatinine) measured up to 12 times over intervals as long as 30 years in the Baltimore Longitudinal Study of Aging (M_age  = 61.21, SD = 15.46; 49% female). There was a modest association between conscientiousness and lower mean-level cortisol that was attenuated only slightly in the fully-adjusted model. Neuroticism and the other traits were unrelated to cortisol levels, and none of the traits was related to cortisol change over time. The null association for neuroticism suggests that its relation with long-term health may be primarily through pathways other than cortisol. The modest association between conscientiousness and 24-h urinary cortisol replicates a previous finding with a longer-term measure of cortisol measured from hair, which calls for more research on the robustness and replicability of this finding. Cortisol may be one pathway through which conscientiousness is associated with health outcomes.

Feasibility of Hair Cortisol as a Biomarker of Chronic Stress in People With Dementia

Hair cortisol concentrations (HCC) are an innovative way to measure chronic stress relying on a small sample of hair. To date, there are no studies that have studied HCC as a biomarker of chronic stress in individuals with dementia. Given the vulnerability to chronic stress in people with dementia, using HCC as an objective measure of physiological stress in those with dementia has potential to enhance our understanding of this population. The goal of this exploratory, multidisciplinary, pilot study was to establish feasibility of HCC testing in people with dementia as a biomarker of chronic stress. HCC was examined over a 6-month period to assess physiological stress response during a transition to memory care. Newly admitted memory care residents ( n = 13, mean age = 82) were followed over 6 months. Residents’ hair samples and health information were collected at 3-month intervals. HCC levels significantly changed during the transition to memory care, which may reflect chronic physiological stress. Participants with frequent behavioral and psychological symptoms of dementia (BPSD) had significantly lower HCC at baseline and exhibited a blunted cortisol reactivity at follow-up. Based on detected changes in HCC, participants likely experienced stress reactions during the transition to memory care, providing preliminary evidence that HCC may be a useful, non-invasive measure of physiological stress in this population. This approach may also be applied to understanding the significance of person-centered care environments on minimizing chronic stress for people with dementia.

Big five traits and interpersonal goals during stressors as predictors of hair cortisol

Background

Hair cortisol concentrations (HCC) provide a biomarker for stress adaptation, which has downstream health consequences. Personality traits (e.g., neuroticism) and social processes (e.g., chronic interpersonal goals) may confer risk or buffer against dysregulated cortisol secretion. However, few studies have examined personality or interpersonal factors predicting hair cortisol, which estimates longer-term secretion and therefore provides a potential biomarker for studying trait-like psychological processes. The present study investigated effects of personality traits and daily interpersonal goals during stressors on HCC.

Method

Participants (N = 90) reported Big Five traits at baseline, recorded interpersonal (self-image and compassionate) goals pursued during their worst psychosocial stressors for 4–5 weeks (1,949 entries), then provided a hair sample to estimate cortisol secretion over the past two months.

Results

As hypothesized, neuroticism predicted higher HCC, beyond other Big Five traits (b = 7.45, SE = 3.36, p = .029). Moreover, this effect was greater for those chronically striving to promote/protect one’s self-image during psychosocial stressors (b = 14.53, SE = 4.72, p = .003), and for those low in conscientiousness (b = 14.84, SE = 4.83, p = .003). Moderate extraversion was associated with higher HCC. Striving to support others (compassionate goals) exerted no direct or interactive effect on HCC, contrary to hypotheses.

Conclusions

Results support the relevance of neuroticism and maladaptive interpersonal strivings to longer-term neuroendocrine responses, suggesting hair cortisol as a potential method for studying links of trait-like psychological and HPA processes.

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Trait neuroticism uniquely predicted higher hair cortisol concentration.

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Interpersonal goals during chronic social stressors amplified effects of neuroticism.

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Trait conscientiousness blunted the effect of neuroticism on hair cortisol.

Deciphering the Association Between Hypothalamus-Pituitary-Adrenal Axis Activity and Obesity: A Meta-Analysis

OBJECTIVE

Both the cortisol awakening response (CAR; corresponding to the state measurement) and hair cortisol concentration (HCC; corresponding to the trait measurement) are considered reliable markers of hypothalamus-pituitary-adrenal axis activity. Because cortisol has long been associated with adiposity, this systematic review and meta-analysis aims to summarize and compare the literature around CAR and HCC and their association with obesity or fat distribution indices.

METHODS

The PubMed, Web of Science (Web of Science Core Collection and Medline), EBSCO Information Services, Embase, and PsycNET databases were searched, and full-text articles investigating the association between CAR or HCC and markers of adiposity in humans were included. Meta-analyses were then performed to compare studies associating CAR or HCC with BMI (a marker of general adiposity) and waist circumference (a marker of fat distribution).

RESULTS

The results of this review highlight inconsistencies in cortisol sampling and CAR computation, which makes comparisons between studies difficult. It was found that adiposity indices are not associated with CAR but that they correlate significantly and positively with HCC. The subgroup analysis hinted to possible age differences in the magnitude of the association between HCC and BMI.

CONCLUSIONS

Trait rather than state measurement of the hypothalamus-pituitary-adrenal axis activity is associated with increased general and abdominal adiposity in humans.

Gender differences in the relationship between personality, cognitive function and regular dental visits in Japanese community-dwelling older adults

OBJECTIVES

Studies have examined the association between personality and health behaviour, but research focusing exclusively on regular dental visits has yet to be conducted. This study examined the association between personality traits and regular dental visits among Japanese community-dwelling older adults.

METHODS

The participants in this cross-sectional study included 1,057 community-dwelling older adults aged 65-74 years from Ranzan and Yoshimi towns; data were collected from October to November 2015 and October to November 2016, respectively. Interviews were conducted to obtain sociodemographic, income, occupation and medical data. The Tokyo Metropolitan Institute of Gerontology Index of Competence was used to assess higher-level competence; general intelligence was also evaluated. The 'Big Five' personality traits-openness to experience, consciousness, neuroticism, extraversion and agreeableness-were also examined. A multivariable logistic regression analysis was performed to examine the relationship between regular dental visits and personality traits.

RESULTS

Among men, the number of natural teeth, current employment status and conscientiousness were associated with dental care utilization. Among women, the number of natural teeth, current annual income, the intellectual activity domain of the Tokyo Metropolitan Institute of Gerontology Index of Competence and openness were significant.

CONCLUSIONS

The factors associated with regular dental visits differed by gender. Overall, work was associated with men's visits, whereas intellectual activity and economic factors were relevant to women. Factors such as personality traits should be considered when addressing barriers to oral health. Understanding personality traits will help practitioners more effectively encourage older adults to make dental visits.

Conscientiousness and perceived physical symptoms: Mediating effect of life events stress and moderating role of resting respiratory sinus arrhythmia

This study investigated the possible psychophysiological links between conscientiousness and perceived physical symptoms by examining the mediating role of life events stress and the moderating role of resting respiratory sinus arrhythmia (RSA). Participants participated in the collection of questionnaire data and physiological data (N = 396). Results showed life events stress mediated the association between conscientiousness and perceived physical symptoms, and the indirect effect was only significant among individuals with lower resting RSA. Findings indicate that low resting RSA as a risk-amplifying physiological marker may magnify the relationship that low conscientiousness affects physical symptoms by increasing life events stress.

Conscientiousness and engagement with national health behaviour guidelines

High conscientiousness is associated with better health and longer life. This relationship is partly accounted for by the performance of health behaviours. The current study aimed to investigate whether conscientiousness was associated with adherence to national health behaviour guidelines as an indicator of healthy lifestyle. A cross-sectional design was used, where participants (N= 886) completed online questionnaires to assess conscientiousness and the facets of conscientiousness (order, virtue, traditionalism, self-control, responsibility, industriousness) and the performance of four health behaviours (fruit and vegetable consumption, alcohol intake, smoking, and physical activity). An index was calculated to combine the health behaviours. Conscientiousness and all its facets significantly predicted the health behaviour guideline index. In comparing high and low conscientious sub-groups, the low conscientious group had lower levels of adherence to all health behaviours guidelines measured. Strikingly, the number of high conscientious participants meeting all health behaviour guidelines was nearly twice the number of low conscientious participants meeting all guidelines. Conscientiousness is associated with adherence to multiple national health behaviour guidelines. Therefore, the positive associations between conscientiousness and health/longevity may be accounted for, in part, by the adoption of a healthy lifestyle across multiple health domains.

Personality and Hypothalamic-Pituitary-Adrenal Axis in Older Men and Women

Personality has been related to health and mortality risk, which has created interest in the biological pathways that could explain this relationship. Although a dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis has been associated with health outcomes and aging, few studies have explored the association between personality and HPA axis functioning in older adults. In addition, it has been suggested that sex could moderate the relationship between personality and HPA axis functioning. Thus, our aim was to analyze the relationship between the big five personality traits and the diurnal cortisol pattern in older adults, as well as sex differences in this relationship. To do so, 79 older people (40 men and 39 women) from 59 to 81 years old (M = 69.19, SD = 4.60) completed the NEO-Five-Factor Inventory (FFI) to measure neuroticism, conscientiousness, extraversion, openness, and agreeableness. Saliva samples were provided on three consecutive days (awakening; 15, 30, and 45 min post-awakening; and bedtime) in order to analyze the diurnal cortisol pattern and, specifically, two cortisol indexes: the cortisol awakening response (CAR) and the diurnal cortisol slope (DCS). Results showed that neuroticism and conscientiousness moderated the diurnal cortisol pattern. Thus, individuals with higher neuroticism and lower conscientiousness scores showed higher bedtime cortisol levels, suggesting a less healthy diurnal cortisol pattern. Regarding the cortisol indexes, higher neuroticism and lower conscientiousness were related to greater CAR and DCS. Sex moderated the association between extraversion and the DCS. Specifically, higher extraversion was related to a lower DCS only in women. Openness and agreeableness were not related to the diurnal cortisol pattern. In conclusion, our results show that in older adults, neuroticism is a vulnerability factor for HPA axis dysregulation, with possible adverse effects on health. By contrast, conscientiousness, and extraversion only in women, appear to be protective factors of HPA axis functioning, with potential beneficial effects on health.

Association of Noncognitive Life Skills With Mortality at Middle and Older Ages in England

IMPORTANCE

Noncognitive life skills are patterns of behavior, thoughts, and feelings that complement cognitive ability in promoting positive economic and educational outcomes. These positive attributes have been associated with favorable social and health outcomes at older ages, but their combined association with survival is not known.

OBJECTIVES

To evaluate the association of the combination of 5 noncognitive life skills with mortality, and to explore the role of sociodemographic, health, cognitive, and behavioral factors in explaining associations.

DESIGN, SETTING, AND PARTICIPANTS

This cohort study used data from wave 5 of the English Longitudinal Study of Ageing, conducted in 2010. Participants included adults 52 years and older. Associations of scores on 5 noncognitive life skills, including conscientiousness, perseverance, emotional stability, optimism, and control, with all-cause mortality were analyzed for a mean (SD) of 7.2 (1.3) years. Data analyses were completed in November 2019.

EXPOSURES

Response to wave 5 of the English Longitudinal Study of Ageing.

MAIN OUTCOMES AND MEASURES

Noncognitive life skills scores, including conscientiousness, perseverance, emotional stability, optimism, and control, were measured by questionnaire. The main outcome was all-cause mortality, and the associations with noncognitive life skills scores were analyzed using Cox proportional hazards regressions models to estimate hazard ratios per 1-SD increase in score.

RESULTS

A total of 7850 participants (mean [SD] age, 66.5 [9.0] years; 4333 [55.2%] women) were included. Combined life skill score was positively associated with survival, with a hazard ratio of 0.81 (95% CI, 0.72-0.90) per 1-SD increase in positive attributes after adjustment for age, sex, race/ethnicity, childhood socioeconomic status, educational attainment, baseline chronic disease, depressive symptoms, cognitive function, mobility impairment, social isolation, smoking, physical activity, alcohol intake, and fruit and vegetable consumption (P < .001). Excluding deaths during 24 months after baseline as a check for reverse causation showed the same pattern (adjusted hazard ratio, 0.79; 95% CI, 0.70-0.89; P < .001). Associations were maintained after each life skill was omitted in turn from the aggregate score, indicating that no single positive attribute accounted for the protective association.

CONCLUSIONS AND RELEVANCE

These findings suggest that noncognitive life skills are associated with survival at older ages. Whether training and education programs could enhance these attributes and influence mortality risk is not known, but fostering and maintaining life skills may be important in later life.

Cardiovascular Disease and Hair Cortisol: a Novel Biomarker of Chronic Stress

PURPOSE OF REVIEW

This review focuses on the concentration of cortisol in human hair as a biomarker of chronic stress in cardiovascular disease (CVD). We outline the cardiovascular consequences of cortisol excess and provide a comprehensive overview of recent studies investigating the relationship of hair cortisol with CVD. In addition, clinical implications and limitations of the evidence are discussed, together with directions for future research.

RECENT FINDINGS

Hair cortisol may be a reliable biomarker of chronic stress since it provides quantification of total cortisol secreted into hair over several weeks. A growing body of evidence suggests that elevated hair cortisol levels are associated with both the incidence of CVD and poorer recovery and treatment outcomes. Moreover, increased hair cortisol concentration has been linked with established cardiometabolic risk factors for CVD including high blood pressure, diabetes, and adiposity. Hair cortisol is a promising biomarker of chronic cortisol excess which may contribute to both the pathogenesis and prognosis of CVD. However, the current evidence relies on small-scale cross-sectional studies. Further research adopting longitudinal designs across larger samples of CVD patients and healthy participants is required to inform the development of novel evidence-based interventions.

The association of potential stressors with hair steroids in parents with small children: The Ulm SPATZ health study

Previous studies have reported weak associations between questionnaire-based stress measurements and hair steroids. A stronger relationship may exist in highly stressed subpopulations or with stress brought up by novel or unpredictable situations. In the Ulm SPATZ Health Study, conducted in Ulm, Germany, baseline recruitment 04/2012 to 05/2013, we analyzed data of families enrolled shortly after childbirth. Mothers completed standardized questionnaires assessing sociodemographic, health- and family-life-related factors, and the Screening Scale of the Trier Inventory of Chronic Stress (TICS) at 6 months (T2) and 12 months postpartum (T3). Their current partners completed SSCS-TICS and an Effort-Reward Imbalance (ERI) Questionnaire obtained at 6 weeks postpartum (T1). Partners (n = 375 at T1) and mothers (n = 654 at T2 or T3) provided a 2 to 3-cm hair segment for hair analysis. Adjusted linear and cubic spline regressions were used to analyze (non-)linear relationships between potential stressors and hair cortisol (hairF) and hair cortisone (hairE) concentrations as well as the respective change scores between 12 months and 6 months. Lacking social recognition and high paternal work overload were significantly associated with paternal hairF in cubic spline models (test for overall association, chi² = 8.24, p = 0.041, chi² = 8.41, p = 0.038) but not in linear models. However, the association between ERI and hairF (chi² = 7.54, p = 0.059) was marginally significant. Maternal education was related to maternal hairF and hairE at T2. No association was observed between maternal postpartum employment and hair steroids at T2 or T3. Conversely, we could show a relationship between some change scores of stress and hairE in mothers. Considering non-linearity and family-related stressors, there are few associations between questionnaire-based stress measurements and hairF or hairE. Novelty of stressors was not shown to be a relevant factor.

Relationship between Personality and Biological Reactivity to Stress: A Review

Objective Personality traits can be the basis for individual differences in the biological response of stress. To date, many psychobiological studies have been conducted to clarify the relationship between personality and biological reactivity to stress. This review summarizes the most important findings in this area of research. Results Key findings related to the relationship between personality factors and stress-sensitive biological systems in four research models have been summarized; model of psychosocial characteristics, model based on Rumination and Emotional Inhibition, Eysenck's biopsychological model, and Five-Factor Approach of Personality. Conclusion According to the results of this review, it can be concluded that personality typology of individuals influenced their biological reactivity to stressful events. Understanding the biological basis of personality can help to better understand vulnerability to stress. Future research can be continuing based on framework of the four models.

Whole Fruits and Fruit Fiber Emerging Health Effects

Less than 10% of most Western populations consume adequate levels of whole fruits and dietary fiber with typical intake being about half of the recommended levels. Evidence of the beneficial health effects of consuming adequate levels of whole fruits has been steadily growing, especially regarding their bioactive fiber prebiotic effects and role in improved weight control, wellness and healthy aging. The primary aim of this narrative review article is to examine the increasing number of health benefits which are associated with the adequate intake of whole fruits, especially fruit fiber, throughout the human lifecycle. These potential health benefits include: protecting colonic gastrointestinal health (e.g., constipation, irritable bowel syndrome, inflammatory bowel diseases, and diverticular disease); promoting long-term weight management; reducing risk of cardiovascular disease, type 2 diabetes and metabolic syndrome; defending against colorectal and lung cancers; improving odds of successful aging; reducing the severity of asthma and chronic obstructive pulmonary disease; enhancing psychological well-being and lowering the risk of depression; contributing to higher bone mineral density in children and adults; reducing risk of seborrheic dermatitis; and helping to attenuate autism spectrum disorder severity. Low whole fruit intake represents a potentially more serious global population health threat than previously recognized, especially in light of the emerging research on whole fruit and fruit fiber health benefits.

Associations of perceived stress with the present and subsequent cortisol levels in fingernails among medical students: a prospective pilot study

Purpose

Cortisol in fingernails could retrospectively reflect cumulative stress over a long period. However, the association between fingernail cortisol and perceived stress needs to be validated. This exploratory study aimed to investigate the associations of perceived stress with the present and subsequent cortisol levels in fingernails of the subjective stress measurement among medical students.

Methods

Students were recruited from a medical university in Shenyang, China. The final sample consisted of 51 students (16 men, 35 women). On the Day 30 of our data and fingernail collection procedure, the 10-item Perceived Stress Scale was used to measure perceived stress. Fingernail samples were collected twice, on Days 15 (denoted as FD15) and 45 (denoted as FD45) of the procedure, and participants were asked to grow fingernails for 15 days in each collection. Cortisol was determined by an enzyme immunoassay method using the ELISA kit. Multiple linear regression was performed to examine the association between perceived stress and cortisol level. The Bonferroni correction was made for multiple comparisons.

Results

The level of cortisol was 5.65 pg/mg (SD =1.88) for FD15 and 5.41 pg/mg (SD =1.63) for FD45. Perceived stress was not associated with the cortisol level of FD15 (β=−0.014, P=0.924), but it was significantly and positively associated with the cortisol level of FD45 (β=0.436, P=0.003), which remained significant after Bonferroni correction. The associations between fingernail cortisol and demographic variables (gender, age, BMI, and physical activity) were not significant.

Conclusion

This study was the first to investigate fingernail cortisol in China. Perceived stress was positively associated with the subsequent cortisol levels in fingernails, but not the present. The findings suggested that fingernail cortisol could indicate stress exposure in the past. Furthermore, a simple and easy self-reported measure could reflect cumulative stress as measured by fingernail cortisol.

Positive and negative social support and HPA-axis hyperactivity: Evidence from glucocorticoids in human hair

INTRODUCTION

While positive social support is associated with lower prevalence of disease and better treatment outcomes, negative social relationships can instead have unfavourable consequences for several physical and mental health conditions. However, the specific mechanisms by which this nexus might operate remain poorly understood. Hypothalamic-pituitary-adrenal (HPA) axis hyperactivity owing to psychosocial stress has been proposed as a potential pathway underlying the link between social support and health. Hair glucocorticoids such as cortisol and cortisone are emerging as promising biomarkers of long-term retrospective HPA activation. Therefore, the aim of this investigation was to examine the effects of positive and negative experiences of social support within key relationships (i.e. spouse/partner, children, other family members, and friends) on cortisol and cortisone.

METHODS

These associations were tested in a sample of 2520 older adults (mean age 68.1) from the English Longitudinal Study of Ageing. Hair samples were collected in wave 6 (2012/13). To understand the impact of cumulative exposure to poor social support, the analysis used self-reported data from waves 4 (2008/09) and 6. Covariates included demographic, socioeconomic, lifestyle, and hair characteristics.

RESULTS

In cross sectional analyses, lower positive support from all sources and specifically from children were associated with higher cortisol. Additionally, lower positive support from children was positively associated with cortisone. Similarly, higher overall negative support was related to higher cortisol, and greater negative support from children was also positively associated with cortisone. In longitudinal analyses, there was evidence for positive associations between hair glucocorticoids and cumulative exposure to poorer social support.

CONCLUSIONS

Experiences of low positive and high negative social support, particularly from children, were both related to higher hair glucocorticoids. Hence, social relationships of poorer quality in later life may have adverse effects on the HPA axis thereby increasing the individual's susceptibility to poor health.

No Evidence for a Relationship Between Hair Testosterone Concentrations and 2D:4D Ratio or Risk Taking

Using a recently developed alternative assay procedure to measure hormone levels from hair samples, we examined the relationships between testosterone, cortisol, 2D:4D ratio, overconfidence and risk taking. A total of 162 (53 male) participants provided a 3 cm sample of hair, a scanned image of their right and left hands from which we determined 2D:4D ratios, and completed measures of overconfidence and behavioral risk taking. While our sample size for males was less than ideal, our results revealed no evidence for a relationship between hair testosterone concentrations, 2D:4D ratios and risk taking. No relationships with overconfidence emerged. Partially consistent with the Dual Hormone Hypothesis, we did find evidence for the interacting effect of testosterone and cortisol on risk taking but only in men. Hair testosterone concentrations were positively related to risk taking when levels of hair cortisol concentrations were low, in men. Our results lend support to the suggestion that endogenous testosterone and 2D:4D ratio are unrelated and might then exert diverging activating vs. organizing effects on behavior. Comparing our results to those reported in the existing literature we speculate that behavioral correlates of testosterone such as direct effects on risk taking may be more sensitive to state-based fluctuations than baseline levels of testosterone.