Katie O'Donnell

Positive affect, psychological well-being, and good sleep.

OBJECTIVE To discover whether positive affect and purpose in life (eudaimonic well-being) are associated with good sleep independently of health problems and socioeconomic status, and to evaluate their role in mediating the influence of psychosocial risk factors on poor sleep. METHODS A cross-sectional study was carried out with 736 men and women aged 58-72 years, with positive affect assessed by aggregating ecological momentary samples. Sleep problems were assessed with the Jenkins Sleep Problems Scale, and psychosocial risk factors were measured by standardized questionnaires. RESULTS Both positive affect and eudaimonic well-being were inversely associated with sleep problems after adjustment for age, gender, household income, and self-rated health (P<.001). Negative psychosocial factors including financial strain, social isolation, low emotional support, negative social interactions, and psychological distress were also related to reported sleep problems. The strength of these associations was reduced by 20-73% when positive affect and eudaimonic well-being were taken into account, suggesting that effects were partly mediated by positive psychological states. CONCLUSIONS These results suggest that both positive affect and eudaimonic well-being are directly associated with good sleep and may buffer the impact of psychosocial risk factors. The relationships are likely to be bidirectional, with disturbed sleep engendering lower positive affect and reduced psychological well-being, and positive psychological states promoting better sleep.

Salivary cortisol responses to mental stress are associated with coronary artery calcification in healthy men and women

AIMS Psychosocial stress is a risk factor for coronary heart disease (CHD), although the mechanisms are incompletely understood. We examined the cross-sectional association between the cortisol response to laboratory-induced mental stress and a marker of sub-clinical coronary atherosclerosis. METHODS AND RESULTS Participants were 514 healthy men and women (mean age = 62.9 +/- 5.7 years), without history or objective signs of CHD, drawn from the Whitehall II epidemiological cohort. Salivary cortisol was measured in response to mental stressors, consisting of a 5 min Stroop task and a 5 min mirror tracing task. Coronary artery calcification (CAC) was measured using electron beam computed tomography. Approximately 40% of the sample responded to the stress tasks with a notable (>or=1 nmol/L) increase in cortisol. Significant CAC (Agatston score >or= 100) was recorded in 23.9% of the sample. The cortisol response group demonstrated a higher risk of significant CAC (odds ratio = 2.20, 95% CI, 1.39-3.47) after adjustments for age, gender, baseline cortisol, employment grade, and conventional risk factors, although cortisol was unrelated to the presence of detectable CAC. Among participants with detectable CAC, the cortisol response group also demonstrated higher log Agatston scores compared with non-responders (age and sex adjusted scores; 4.51 +/- 0.15 vs. 3.94 +/- 0.13, P = 0.004). CONCLUSION In healthy, older participants without history or objective signs of CHD, heightened cortisol reactivity is associated with a greater extent of CAC. These data support the notion that heightened hypothalamic pituitary adrenal activity is a risk factor for CHD.

Psychological coping styles and cortisol over the day in healthy older adults.

Patterns of psychological coping are associated with a variety of health outcomes but the underlying pathways are not yet established. The purpose of this study was to assess the relationship between salivary cortisol output over the course of a day and coping style. Data were available from 350 men and 192 women with an average age of 60.9 years. Participants were drawn from the Whitehall II cohort, and had no history of cardiovascular disease. Individuals who were taking medication that might affect cortisol levels were also excluded. Saliva samples were provided on waking, then 0.5, 2.5, 8 and 12h after waking, and just before the participant went to sleep. Coping style was measured with a standard instrument, the COPE, and data were factor analysed to generate three factors: seeking social support, problem engagement and problem avoidance. The relationships between these factors and the cortisol awakening response (CAR), the slope of cortisol change over the day and total cortisol output over the day (excluding the waking period) were assessed using multiple linear regression. Cortisol output over the day was inversely associated with coping with stress by seeking social support (p=0.034) and by problem engagement (p=0.003), independently of age, gender, body mass index, smoking, depression, self-rated health, time of waking and income. Individuals who coped by problem engagement and seeking support had lower cortisol levels. Additionally, gender, BMI, smoking, self-rated health and time of waking were independently related to cortisol output over the day. There were no significant associations between coping and the CAR or cortisol slope over the day. The results indicate that adaptive coping styles are related to low levels of cortisol over the day, suggesting that neuroendocrine pathways may partly mediate relationships between psychological coping and health.

Self-esteem levels and cardiovascular and inflammatory responses to acute stress

Acute mental stress tests have helped to clarify the pathways through which psychosocial factors are linked to disease risk. This methodology is now being used to investigate potentially protective psychosocial factors. We investigated whether global self-esteem might buffer cardiovascular and inflammatory responses to acute stress. One hundred and one students completed the Rosenberg Self-Esteem Scale. Heart rate and heart rate variability (HRV) were recorded for 5 min periods at baseline, during two mental stress tasks, (a speech and a color-word task) and 10, 25 and 40 min into a recovery period. Plasma levels of tumor-necrosis factor-alpha (TNF-alpha), interleukin-6 (IL-6) and interleukin-1 receptor antagonist (IL-1Ra) were assessed at baseline, immediately post-stress and after 45 min recovery. Repeated measures analysis of variance demonstrated that heart rate levels were lower across all time points in those with high self-esteem, although heart rate reactivity to stress was not related to self-esteem. There were no differences in baseline HRV, TNF-alpha, IL-6 or IL-1Ra. Multiple linear regressions revealed that greater self-esteem was associated with a smaller reduction in heart rate variability during the speech task, but not the color-word task. Greater self-esteem was associated with smaller TNF-alpha and IL-1Ra responses immediately following acute stress and smaller IL-1Ra responses at 45 min post-stress. In conclusion, global self-esteem is associated with lower heart rate and attenuated HRV and inflammatory responses to acute stress. These responses could be processes through which self-esteem protects against the development of disease.

Stress-induced cytokine responses and central adiposity in young women

Background:Evidence suggests that people who are more responsive to psychological stress are at an increased risk of developing obesity. However, the biological mechanisms underlying this phenomenon are poorly understood. The cytokines leptin, interleukin-1 receptor antagonist (IL-1Ra) and interleukin-6 (IL-6) play a key role in fat metabolism and abnormal circulating levels of these proteins have been reported in obese people and in individuals subject to stress.Objective:This study investigated whether cytokine responses to acute mental stress are associated with adiposity in healthy young women.Design and Subjects:A laboratory study of 67 women, aged 18–25 years, recruited from University College London.Measurements:Height, weight and waist circumference were measured and body fat mass was estimated by bioelectrical impedance body composition analysis. Laboratory mental stress testing was carried out and blood pressure and heart rate were recorded at baseline, during two moderately challenging tasks (Stroop and speech) and during recovery 40–45 min post-stress. Blood samples taken at baseline, immediately post-stress and 45 min post-stress, were used for assessment of circulating cytokines. Saliva samples taken throughout the session were assessed for cortisol.Results:Women who had larger cytokine responses to stress were more abdominally obese than women with smaller cytokine stress responses. Specifically, there was a positive correlation between waist circumference and stress-induced increases in plasma levels of leptin (r=0.35, P<0.05) and IL-1Ra responses (r=0.29, P<0.05). There was also a significant positive correlation between prolonged diastolic blood pressure responses to stress and measures of total and abdominal obesity (r=0.28–0.33, P<0.05).Conclusion:Increased cytokine production could be a mechanism linking stress and abdominal obesity.

Delayed Blood Pressure Recovery After Psychological Stress Is Associated With Carotid Intima-Media Thickness Whitehall Psychobiology Study

Objective—Delayed blood pressure (BP) recovery after psychological stress is associated with low socioeconomic status (SES) and prospectively with increases in clinic BP. We tested whether poststress BP recovery was related to carotid atherosclerosis. Methods and Results—Psychophysiological stress testing was performed with a healthy subgroup of the Whitehall II epidemiological cohort, and recovery systolic BP was monitored 40 to 45 minutes after stressful behavioral tasks. Carotid ultrasound scanning was conducted on 136 men and women (aged 55.3±2.7 years) 3 years after stress testing. Participants were divided into those whose systolic BP had returned to baseline in the recovery period (adequate recovery, n=37), and those whose BP remained elevated (delayed recovery, n=99). Systolic BP stress responses did not differ in the 2 groups. Carotid intima-media thickness (IMT) was associated with delayed recovery in lower SES (means 0.78 versus 0.65 mm) but not higher SES participants (means 0.75 versus 0.74 mm) after adjustment for age, gender, baseline systolic BP, and resting BP, smoking, body mass and fasting cholesterol at the time of ultrasound scanning (P=0.010). Conclusions—Variations in poststress recovery reflect dysfunction of biological regulatory processes, and may partly mediate psychosocial influences on cardiovascular disease.

Plasma heat shock protein 60 and cardiovascular disease risk: the role of psychosocial, genetic, and biological factors

Abstract The Whitehall Study is a prospective epidemiological study of cardiovascular risk factors in healthy members of the British Civil Service, which has identified psychological distress as a major risk factor for coronary heart disease. The levels of circulating Hsp60 in 860 participants from the Whitehall cohort and 761 individuals diagnosed with diabetes have been measured and related to psychological, biological, and genetic factors. In the Whitehall participants, concentrations of Hsp60 ranged from undetectable to mg/mL levels. Circulating Hsp60 correlated with total and low-density lipoprotein (LDL) cholesterol and was positively associated with a flattened slope of cortisol decline over the day. Levels of this stress protein also correlated with measures of psychological stress including psychological distress, job demand, and low emotional support. Mass spectrometric analysis of circulating immunoreactive Hsp60 reveal that it is predominantly the intact protein with no mitochondrial import peptide, suggesting that this circulating protein emanates from mitochondria. The Hsp60 is stable when added to plasma and the levels in the circulation of individuals are remarkably constant over a 4-year period, suggesting plasma levels are partly genetically controlled. Sequence analysis of the HSP60-HSP10 intergenic promoter region identified a common variant 3175 C>G where the G allele had a frequency of 0.30 and was associated with higher Hsp60 levels in 761 type 2 diabetic patients. The extended range of plasma Hsp60 concentrations in the general population is genuine and is likely to be related to genetic, biological, and psychosocial risk factors for coronary artery disease.

Socioeconomic status and subclinical coronary disease in the Whitehall II epidemiological study.

Background There are pronounced socioeconomic disparities in coronary heart disease, but the extent to which these primarily reflect gradients in underlying coronary artery disease severity or in the clinical manifestation of advanced disease is uncertain. We measured the relationship between socioeconomic status (SES) as indexed by grade of employment and coronary artery calcification (CAC) in the Whitehall II epidemiological cohort, and tested the contribution of lifestyle, biological and psychosocial factors in accounting for this association. Methods and Findings CAC was assessed in 528 asymptomatic men and women aged 53–76 years, stratified into higher, intermediate and lower by grade of employment groups. Lifestyle (smoking, body mass index, alcohol consumption, physical activity), biological (blood pressure, lipids, fasting glucose, inflammatory markers) and psychosocial factors (work stress, financial strain, social support, depression, hostility, optimism) were also measured. Detectable CAC was present in 293 participants (55.5%). The presence of calcification was related to lifestyle and biological risk factors, but not to grade of employment. But among individuals with detectable calcification, the severity of CAC was inversely associated with grade of employment (p = 0.010), and this relationship remained after controlling for demographic, lifestyle, biological and psychosocial factors. Compared with the higher grade group, there was a mean increase in log Agatston scores of 0.783 (95% C.I. 0.265–1.302, p = 0.003) in the intermediate and 0.941 (C.I. 0.226–1.657, p = 0.010) in the lower grade of employment groups, after adjustment for demographic, lifestyle, biological and psychosocial factors. Conclusions Low grade of employment did not predict the presence of calcification in this cohort, but was related to the severity of CAC. These findings suggest that lower SES may be particularly relevant at advanced stages of subclinical coronary artery disease, when calcification has developed.

Circulating Leptin and Stress-induced Cardiovascular Activity in Humans

Obesity is associated with an elevated risk of hypertension and cardiovascular disease. The adipocyte hormone leptin, which stimulates energy expenditure in animals by activating the sympathetic nervous system (SNS), is believed to play a role in this association. However, evidence in humans remains sparse. We investigated the relationship between circulating leptin and cardiovascular and inflammatory responses to acute psychological stress in humans. Participants were 32 men and 62 women aged 18–25 years. Cardiovascular activity was assessed using impedance cardiography at baseline, during acute laboratory stress, and during a 45‐min recovery period. Plasma cytokines were measured in blood drawn at baseline and 45‐min poststress. In women only, baseline plasma leptin was significantly associated with stress‐induced changes in heart rate (β = 0.53, P = 0.006), heart rate variability (HRV) (β = −0.44, P = 0.015), and cardiac preejection period (PEP) (β = −0.51, P = 0.004), independent of age, adiposity, and smoking. Womens plasma leptin levels also correlated with stress‐induced elevations in the proinflammatory cytokine interleukin‐6 (IL‐6) (β = 0.35, P = 0.042). Circulating leptin is an independent predictor of sympathetic cardiovascular activity, parasympathetic withdrawal, and inflammatory responses to stress in women. Because cardiovascular and inflammatory stress responses are predictive of future cardiovascular disease, leptin may be a mechanism mediating the adverse effects of stress and obesity on womens cardiovascular health.

Social Support in Trauma

Trauma arising from natural and technological disasters or mass violence is a pervasive feature of life. Social support is rapidly mobilized in many of these situations, although it often fails to reach those who need it most. Favorable adaptation is associated with the extent of the received social support. However, people experiencing disasters may be disappointed at the support they actually receive, leading to support deterioration.