Bradley J. Wright

Psychosocial predictors of irritable bowel syndrome diagnosis and symptom severity.

OBJECTIVE This study explored the role of psychosocial factors in predicting both membership to either an irritable bowel syndrome (IBS) or control group, and the severity of IBS symptoms. METHODS A total of 149 participants (82 IBS and 67 controls) completed a battery of self-report inventories assessing disposition and environment, cognitive processes, and psychological distress. Logistic regression analyses were used to assess predictive contribution of psychosocial variables to IBS diagnosis. Hierarchical linear regression was then used to assess the relationship of psychosocial variables with the severity of IBS symptoms. RESULTS Significant predictors of IBS were found to be alexithymia, the defectiveness/shame schema, and four coping dimensions (active coping, instrumental support, self-blame, and positive reframing), χ(2) (6, N=130)=46.99, p<.001, with predictive accuracy of 72%. Significant predictors of IBS symptom severity were two of the alexithymia subscales (difficulty identifying feelings, and difficulty describing feelings), gender, the schemas of defectiveness/shame and entitlement, and global psychological distress. This model predicted IBS severity F (6, 64)=16.94, p<.001 and accounted for 61.3% of the variability in IBS severity scores. CONCLUSION Psychosocial variables account for a large percentage of the differences between an IBS and control group, as well as the variance of symptoms experienced within the IBS group. Alexithymia and the defectiveness schema appear to be related to both IBS and symptom severity.

Calorie restriction increases lipopolysaccharide-induced neuropeptide Y immunolabeling and reduces microglial cell area in the arcuate hypothalamic nucleus.

Calorie restriction (CR) increases longevity and elicits many health promoting benefits including delaying immunosenescence and reducing the incidence of age-related diseases. Although the mechanisms underlying the health-enhancing effects of CR are not known, a likely contributing factor is alterations in immune system functioning. CR suppresses lipopolysaccharide (LPS)-induced release of pro-inflammatory cytokines, blocks LPS-induced fever, and shifts hypothalamic signaling pathways to an anti-inflammatory bias. Furthermore, we have recently shown that CR attenuates LPS-stimulated microglial activation in the hypothalamic arcuate nucleus (ARC), a brain region containing neurons that synthesize neuropeptide Y (NPY), an orexigenic neuropeptide that is upregulated by a CR diet and has anti-inflammatory properties. To determine if increased NPY expression in the ARC following CR was associated with changes in microglial activation, a set of brain sections from mice that were exposed to 50% CR or ad libitum feeding for 28 days before being injected with LPS were immunostained for NPY. The density of NPY-immunolabeling was assessed across the rostrocaudal extent of the ARC and hypothalamic paraventricular nucleus (PVN). An adjacent set of sections were immunostained for ionized calcium-binding adapter molecule-1 (Iba1) and immunostained microglia in the ARC were digitally reconstructed to investigate the effects of CR on microglial morphology. We demonstrated that exposure to CR increased NPY expression in the ARC, but not the PVN. Digital reconstruction of microglia revealed that LPS increased Iba1 intensity in ad libitum fed mice but had no effect on Iba1 intensity in CR mice. CR also decreased the size of ARC microglial cells following LPS. Correlational analyses revealed strong associations between NPY and body temperature, and body temperature and microglia area. Together these results suggest that CR-induced changes in NPY are not directly involved in the suppression of LPS-induced microglial activation, however, NPY may indirectly affect microglial morphology through changes in body temperature.

A Systematic Review and Meta-analysis of the Effort-reward Imbalance Model of Workplace Stress and HPA Axis Measures of Stress

Objective The association between effort-reward imbalance (ERI) and various health outcomes has been well documented over the past 20 years, but the mechanisms responsible for this association remain unclear. The present meta-analysis assessed the associations of ERI and overcommitment (OC) in the workplace with hypothalamic-pituitary-adrenal (HPA) axis measures. Methods Electronic databases were searched with the phrase “effort*reward*imbalance,” which yielded 319 studies leading to 56 full-text studies being screened. Thirty-two studies within 14 articles met inclusion criteria and were meta-analyzed using mixed and random effects models. Results Greater ERI was associated with increased HPA axis activity (r = .09, p < .001, k = 14, N = 2541). The cortisol awakening response (r = .14, p < .001, k = 9, N = 584) and cortisol waking concentrations (r = .12, p = .01, k = 6, N = 493) were the only HPA measures associated with ERI. OC was also associated with greater HPA axis activity (r = .06, p < .01, k = 10, N = 1918). Cortisol (PM) (r = .13, p = .02, k = 3, N = 295) was the only HPA measure associated with OC. Conclusions ERI and OC were similarly related with HPA responsivity. However, because OC moderated the relationship between ERI and HPA axis markers, the importance of OC should not be overlooked. Because OC is likely more malleable than ERI to intervention, this may be a promising avenue for future research.

Associations between the effort-reward imbalance model of workplace stress and indices of cardiovascular health: A systematic review and meta-analysis

HighlightsERI and OC were most associated with IMT and fibrinogen.Sex moderates the association between OC and both IMT and mean BP.OC moderates the association between ERI and fibrinogen.‘White coat effect’ may explain disparity in ERI and hypertension associations. Abstract Work stress can increase the risk of cardiovascular disease by 50%, with increasing research focusing on the underlying mechanisms responsible for these associations. Our meta‐analysis assessed the associations of the effort‐reward imbalance (ERI) workplace stress model with indices of cardiovascular disease. The search term ‘effort*reward*imbalance’ produced 22 papers (129 associations, N = 93,817) meeting inclusion criteria. Greater ERI was most associated with increased hypertension (r = 0.26, p < 0.001, N = 1180), intima media thickness (r = 0.23, p < .001, N = 828) and fibrinogen (r = 0.13, p = 0.03, N = 4315). Trait over‐commitment was most associated with increased hypertension (r = 0.24, p =0.02, N = 899) and intima media thickness (r = 0.19, p = 0.02, N = 828). Interventions aimed at reducing the impact of ERI and over‐commitment on cardiovascular disease should consider concurrently assessing changes in physiological markers of cardiovascular disease.

An experimental examination of the effort-reward imbalance model of occupational stress: Increased financial reward is related to reduced stress physiology

Effort-reward imbalance in the workplace is linked to a variety of negative health and organisational outcomes, but it has rarely been assessed experimentally. We manipulated reward (while keeping effort constant) in a within-subjects design with female participants (N=60) who were randomly assigned to high and standard reward conditions within a simulated office environment. Self-report, behavioural (task performance), and physiological (heart rate variability, salivary alpha amylase) measures assessed the impact of increased financial reward. Participants reported increased perceptions of reward, performed moderately better on the task, and were less physiologically reactive in the high reward versus the standard condition. These findings highlight the importance of assessing both subjective self-reports of stress together with objective physiological measures of stress, and suggest that increasing monetary rewards has the potential to decrease stress physiological reactivity, and in turn, reduce the risk of ill-health in employees, and may also positively influence task efficacy.

Irritable bowel syndrome and symptom severity: Evidence of negative attention bias, diminished vigour, and autonomic dysregulation

OBJECTIVE To determine if cognitive processing, and subjective and physiological responses to stress and relaxation differed between an irritable bowel syndrome (IBS) group and control group. How these variables relate to the severity of IBS symptoms was also determined. METHODS Twenty-one IBS participants and 20 controls provided cognitive (attention and processing), subjective (perceived stress and vigour), and physiological (heart rate, blood pressure, and skin conductance) data during a relaxation and stress phase. Logistic regression analyses determined which variables are related to the IBS group and hierarchical linear regression assessed how the variables are related to the severity of IBS symptoms. RESULTS Subjective and cognitive factors (drowsiness at baseline, total vigour, and reduced Stroop colour-naming accuracy for negative words) are significantly related to IBS, χ2 (3, N=41)=23.67, p<.001, accurately categorising 85% of participants. IBS symptom severity was associated with both subjective (drowsiness at baseline and a smaller reduction in tiredness from relaxation to stress) and physiological (smaller increase in systolic blood pressure from baseline to stress phase and lower skin conductance at baseline) variables. This model predicted IBS severity, F (4, 16)=11.20, p<.001, and accounted for 74% of the variability in scores. CONCLUSIONS A negative attention bias, which may be related to a negative self-schema, as well as perceived low vigour were important in categorising IBS. Low subjective vigour and reduced physiological reactivity to both relaxation and stress conditions were associated with IBS severity, suggestive of illness-related allostatic load.

Perceived Success, Auditory Feedback, and Mental Imagery: What Best Predicts Improved Efficacy and Motor Performance?

Purpose: Performance enhancement techniques can improve self-efficacy (SE) and task performance. The focus of this study was to determine which techniques could best achieve this with three novel tasks. Method: Participants (n = 98) were counterbalanced across tasks and conditions (48 participants assigned to each condition in each task) and completed two trials of putting (imagery vs. no imagery), throwing (easy vs. difficult), and kicking (verbal feedback vs. no feedback) tasks, and SE and performance scores were recorded. Results: The results revealed that the auditory feedback condition had the greatest impact as it significantly explained both SE and performance scores, with a greater effect recorded for SE scores. Use of imagery or allocation to the easy-to-score condition did not improve performance or SE scores more than did the control conditions. Conclusions: These findings were unexpected as successful past performance is often cited as the main determinant of SE change. Further empirical investigation is required to determine if these findings are repeatable and if they generalize to sporting settings.

Enhancing Self-Efficacy and Performance: An Experimental Comparison of Psychological Techniques

Purpose: We assessed how 6 psychological performance enhancement techniques (PETs) differentially improved self-efficacy (SE) and skill performance. We also assessed whether vicarious experiences and verbal persuasion as posited sources of SE (Bandura, 1982) were supported and, further, if the effects of the 6 PETs remained after controlling for achievement motivation traits and self-esteem. Method: A within-subject design assessed each individual across 2 trials for 3 disparate PETs. A between-groups design assessed differences between PETs paired against each other for 3 similar novel tasks. Participants (N = 96) performed 2 trials of 10 attempts at each of the tasks (kick, throw, golf putt) in a counterbalanced sequence using their nondominant limb. Participants completed the Sport Orientation Questionnaire, Rosenberg Self-Esteem Scale, and General Self-Efficacy Scale and were randomly allocated to either the modeling or imagery, goal-setting or instructional self-statement, or knowledge-of-results or motivational feedback conditions aligned with each task. Results: An instructional self-statement improved performance better than imagery, modeling, goal setting, and motivational and knowledge-of-results augmented feedback. Motivational auditory feedback most improved SE. Increased SE change scores were related to increased performance difference scores on all tasks after controlling for age, sex, achievement motivation, and self-esteem. Conclusions: Some sources of SE may be more influential than others on both SE and performance improvements. We provide partial support for the sources of SE proposed by Banduras social-cognitive theory with verbal persuasion but not vicarious experiences improving SE.

Increased systolic blood pressure reactivity to acute stress is related with better self-reported health

The stress reactivity hypothesis posits that the magnitude of cardiovascular reactions to acute stress tasks is related with future blood pressure status, heart hypertrophy, and atherosclerosis. We assessed the stress reactivity hypothesis and aimed to identify which physiological indices (blood pressure, heart-rate, cortisol, salivary immunoglobulin A (sIgA)) related to self-reported mental and physical health. We also assessed if physiological reactions elicited by an acute stressor were more related than basal assessments. Participants provided physiological samples, self-reported stress and health-data before and after an assessed 5–7 minute academic oral presentation. In hierarchical regression models, increased systolic and reduced sIgA reactivity was associated with better perceptions of mental health. Reactivity data were more related to self-reported data than basal data. In line with the only 2 studies to assess the reactivity hypothesis with self-perceived health, increased systolic reactivity was best associated with better perceived physical and mental health. The findings suggest that increased SBP reactivity may also be associated with positive health outcomes. Further research is required to determine if increased or decreased sIgA reactivity is most predictive of future morbidity.

Identifying the sources of stress and rewards in a group of Australian apprentice jockeys

Abstract Previous stress-in-sport research has generally focused on elite athletes while overlooking the experiences of professional, paid athletes. Similarly, despite their susceptibility to chronic stress, professional athletes have rarely been examined by occupational stress researchers, and little is known about the adverse health effects of the stressors they experience. Despite the unique demands faced by jockeys, there is a paucity of research examining the incidence and impact of occupational stress on professional jockeys within the thoroughbred racing industry. This paper describes the results of a qualitative study aimed at identifying the sources of stress (demands vs. rewards) experienced by a group of Australian professional apprentice jockeys. The study also aimed to investigate whether the effort–reward imbalance (ERI) model of occupational stress can be generalised to this group of professional athletes. Thirty-five apprentice jockeys registered in an apprentice jockey training programme in an Australian capital city took part in semi-structured focus group discussions. Five major themes relating to demands emerged: time demands, role suppression, physical demands, cognitive demands and ancillary demands. Demands not only stemmed from the competitive environment, but also from the broader work environment. Five themes emerged relating to rewards: financial rewards, positive emotion, status, winning and new experiences, which generally aligned with the categories highlighted by the ERI model. Although undoubtedly a challenging career, it also emerged as an extremely rewarding vocation. For this group of apprentice jockeys, it is conceivable that the rewards outweigh the demands of the occupation.