Yoichi Chida

The effects of acute psychological stress on circulating inflammatory factors in humans: A review and meta-analysis

Stress influences circulating inflammatory markers, and these effects may mediate the influence of psychosocial factors on cardiovascular risk and other conditions such as psoriasis and rheumatoid arthritis. Inflammatory responses can be investigated under controlled experimental conditions in humans, and evidence is beginning to emerge showing that circulating inflammatory factors respond to acute psychological stress under laboratory conditions. However, research published to date has varied greatly in the composition of study groups, the timing of samples, assay methods, and the type of challenge imposed. The purpose of this review is to synthesize existing data using meta-analytic techniques. Thirty studies met inclusion criteria. Results showed robust effects for increased levels of circulating IL-6 (r=0.19, p=0.001) and IL-1beta (r=0.58, p<0.001) following acute stress, and marginal effects for CRP (r=0.12, p=0.088). The effects of stress on stimulated cytokine production were less consistent. Significant variation in the inflammatory response was also related to the health status of participants and the timing of post-stress samples. A number of psychobiological mechanisms may underlie responses, including stress-induced reductions in plasma volume, upregulation of synthesis, or enlargement of the cell pool contributing to synthesis. The acute stress-induced inflammatory response may have implications for future health, and has become an important topic of psychoneuroimmunological research.

Positive Psychological Well-being and Mortality: A Quantitative Review of Prospective Observational Studies

Objective: To review systematically prospective, observational, cohort studies of the association between positive well-being and mortality using meta-analytic methods. Recent years have witnessed increased interest in the relationship between positive psychological well-being and physical health. Methods: We searched general bibliographic databases: Medline, PsycINFO, Web of Science, and PubMed up to January 2008. Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. Results: There were 35 studies (26 articles) investigating mortality in initially healthy populations and 35 studies (28 articles) of disease populations. The meta-analyses showed that positive psychological well-being was associated with reduced mortality in both the healthy population (combined hazard ratio (HR) = 0.82; 95% Confidence Interval (CI) = 0.76–0.89; p < .001) and the disease population (combined HR = 0.98; CI = 0.95–1.00; p = .030) studies. There were indications of publication bias in this literature, although the fail-safe numbers were 2444 and 1397 for healthy and disease population studies, respectively. Intriguingly, meta-analysis of studies that controlled for negative affect showed that the protective effects of positive psychological well-being were independent of negative affect. Both positive affect (e.g., emotional well-being, positive mood, joy, happiness, vigor, energy) and positive trait-like dispositions (e.g., life satisfaction, hopefulness, optimism, sense of humor) were associated with reduced mortality in healthy population studies. Positive psychological well-being was significantly associated with reduced cardiovascular mortality in healthy population studies, and with reduced death rates in patients with renal failure and with human immunodeficiency virus-infection. Conclusions: The current review suggests that positive psychological well-being has a favorable effect on survival in both healthy and diseased populations. CHD = coronary heart disease; CI = Confidence Interval; HIV = human immunodeficiency virus-infection; HR = hazard ratio; ln = natural logarithm; RR = relative risk.

Cortisol awakening response and psychosocial factors: A systematic review and meta-analysis

The magnitude of the cortisol awakening response, a relatively new indicator of hypothalamic-pituitary-adrenocortical (HPA) axis activation, has been related to a number of psychosocial factors. But findings have been inconsistent across studies. We systematically reviewed previous studies investigating the association between the cortisol awakening response and psychosocial factors. 147 eligible studies from 62 articles were identified. Separate analyses were carried out on the increase in cortisol following waking (CARi), and the integrated volume of cortisol released over the waking period (CARauc). We found that the CARi was positively associated with job stress and general life stress. It was negatively associated with fatigue, burnout, or exhaustion. There were less reliable negative associations between the CARi and positive affects. The CARauc was positively related to general life stress and negatively related to posttraumatic stress syndrome. This review concludes that different psychosocial factors are associated with an enhanced or reduced cortisol awakening response.

Physical activity and risk of neurodegenerative disease: a systematic review of prospective evidence.

BACKGROUND The association between physical activity and risk of neurodegenerative diseases is not well established. We therefore aimed to quantify this association using meta-analytical techniques. METHOD We searched Medline, the Cochrane Database of Systematic Reviews and Web of Science databases from 1990 to 2007 for prospective epidemiological studies of physical activity and incident dementia, Alzheimers and Parkinsons disease. We excluded studies of physical activity and cognitive decline without diagnosis of a neurodegenerative disease. Information on study design, participant characteristics, measurement of exposure and outcome variables, adjustment for potential confounding, and estimates of associations was abstracted independently by the two investigators. RESULTS We included 16 prospective studies in the overall analysis, which incorporated 163797 non-demented participants at baseline with 3,219 cases at follow-up. We calculated pooled relative risk (RR) using a random effects model. The RR of dementia in the highest physical activity category compared with the lowest was 0.72 [95% confidence interval (CI) 0.60-0.86, p<0.001], for Alzheimers, 0.55 (95% CI 0.36-0.84, p=0.006), and for Parkinsons 0.82 (95% CI 0.57-1.18, p=0.28). CONCLUSIONS Our results suggest that physical activity is inversely associated with risk of dementia. Future studies should examine the optimal dose of physical activity to induce protection, which presently remains unclear.

Do stress-related psychosocial factors contribute to cancer incidence and survival?

A substantial body of research has investigated the associations between stress-related psychosocial factors and cancer outcomes. Previous narrative reviews have been inconclusive. In this Review, we evaluated longitudinal associations between stress and cancer using meta-analytic methods. The results of 165 studies indicate that stress-related psychosocial factors are associated with higher cancer incidence in initially healthy populations (P = 0.005); in addition, poorer survival in patients with diagnosed cancer was noted in 330 studies (P <0.001), and higher cancer mortality was seen in 53 studies (P <0.001). Subgroup meta-analyses demonstrate that stressful life experiences are related to poorer cancer survival and higher mortality but not to an increased incidence. Stress-prone personality or unfavorable coping styles and negative emotional responses or poor quality of life were related to higher cancer incidence, poorer cancer survival and higher cancer mortality. Site-specific analyses indicate that psychosocial factors are associated with a higher incidence of lung cancer and poorer survival in patients with breast, lung, head and neck, hepatobiliary, and lymphoid or hematopoietic cancers. These analyses suggest that stress-related psychosocial factors have an adverse effect on cancer incidence and survival, although there is evidence of publication bias and results should be interpreted with caution.

The Association of Anger and Hostility With Future Coronary Heart Disease: A Meta-Analytic Review of Prospective Evidence

OBJECTIVES This review aimed to evaluate the association between anger and hostility and coronary heart disease (CHD) in prospective cohort studies using quantitative methods. BACKGROUND The harmful effect of anger and hostility on CHD has been widely asserted, but previous reviews have been inconclusive. METHODS We searched general bibliographic databases: MEDLINE, PsycINFO, Web of Science, and PubMed up to November 2008. Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. RESULTS There were 25 studies (21 articles) investigating CHD outcomes in initially healthy populations and 19 studies (18 articles) of samples with existing CHD. Anger and hostility were associated with increased CHD events in the healthy population studies (combined hazard ratio [HR]: 1.19; 95% confidence interval [CI]: 1.05 to 1.35, p = 0.008) and with poor prognosis in the CHD population studies (HR: 1.24; 95% CI: 1.08 to 1.42, p = 0.002). There were indications of publication bias in these reports, although the fail-safe numbers were 2,020 and 750 for healthy and disease population studies, respectively. Intriguingly, the harmful effect of anger and hostility on CHD events in the healthy populations was greater in men than women. In studies of participants with CHD at baseline that controlled fully for basal disease status and treatment, the association of anger and hostility with poor prognosis persisted. CONCLUSIONS The current review suggests that anger and hostility are associated with CHD outcomes both in healthy and CHD populations. Besides conventional physical and pharmacological interventions, this supports the use of psychological management focusing on anger and hostility in the prevention and treatment of CHD.

Greater Cardiovascular Responses to Laboratory Mental Stress Are Associated With Poor Subsequent Cardiovascular Risk Status. A Meta-Analysis of Prospective Evidence

An increasing number of studies has tested whether greater cardiovascular responses to acute mental stress predict future cardiovascular disease, but results have been variable. This review aimed quantitatively to evaluate the association between cardiovascular responses to laboratory mental stress and subsequent cardiovascular risk status in prospective cohort studies. We searched general bibliographic databases, PsycINFO, Web of Science, and PubMed, up to December 2009. Two reviewers independently extracted data on study characteristics, quality, and estimates of associations. There were 169 associations (36 articles) of stress reactivity and 30 associations (5 articles) of poststress recovery in relation to future cardiovascular risk status, including elevated blood pressure, hypertension, left ventricular mass, subclinical atherosclerosis, and clinical cardiac events. The overall meta-analyses showed that greater reactivity to and poor recovery from stress were associated longitudinally with poor cardiovascular status (r=0.091 [95% CI: 0.050 to 0.132], P<0.001, and r=0.096 [95% CI: 0.058 to 0.134], P<0.001, respectively). These findings were supported by more conservative analyses of aggregate effects and by subgroup analyses of the methodologically strong associations. Notably, incident hypertension and increased carotid intima-media thickness were more consistently predicted by greater stress reactivity and poor stress recovery, respectively, whereas both factors were associated with higher future systolic and diastolic blood pressures. In conclusion, the current meta-analysis suggests that greater responsivity to acute mental stress has an adverse effect on future cardiovascular risk status, supporting the use of methods of managing stress responsivity in the prevention and treatment of cardiovascular disease.

Chronic psychosocial factors and acute physiological responses to laboratory-induced stress in healthy populations: a quantitative review of 30 years of investigations.

This meta-analysis included 729 studies from 161 articles investigating how acute stress responsivity (including stress reactivity and recovery of hypothalamic-pituitary-adrenal [HPA] axis, autonomic, and cardiovascular systems) changes with various chronic psychosocial exposures (job stress; general life stress; depression or hopelessness; anxiety, neuroticism, or negative affect; hostility, aggression, or Type-A behavior; fatigue, burnout, or exhaustion; positive psychological states or traits) in healthy populations. In either the overall meta-analysis or the methodologically strong subanalysis, positive psychological states or traits were associated with reduced HPA reactivity. Hostility, aggression, or Type-A behavior was associated with increased cardiovascular (heart rate or blood pressure) reactivity, whereas anxiety, neuroticism, or negative affect was associated with decreased cardiovascular reactivity. General life stress and anxiety, neuroticism, or negative affect were associated with poorer cardiovascular recovery. However, regarding the sympathetic nervous system and parasympathetic nervous system, there were no associations between the chronic psychosocial factors and stress reactivity or recovery. The results largely reflect an integrated stress response pattern of hypo- or hyperactivity depending on the specific nature of the psychosocial background.

Walking and Primary Prevention: A Meta-analysis of Prospective Cohort Studies

Objective: To quantify the association between walking and the risk of cardiovascular disease (CVD) and all-cause mortality in healthy men and women. Data sources: Medline, Cochrane Database of Systematic Reviews, and Web of Science databases were searched to May 2007. Study selection: Prospective epidemiological studies of walking and CVD and all-cause mortality. Results: 18 prospective studies were included in the overall analysis, which incorporated 459 833 participants free from CVD at baseline with 19 249 cases at follow-up. From the meta-analysis the pooled hazard ratio of CVD in the highest walking category compared with the lowest was 0.69, (95% CI 0.61 to 0.77, p<0.001), and 0.68 (0.59 to 0.78, p<0.001) for all-cause mortality. These effects were robust among men and women, although there was evidence of publication biases for the associations with CVD risk. Walking pace was a stronger independent predictor of overall risk compared with walking volume (48% versus 26% risk reductions, respectively). There was also evidence of a dose–response relationship across the highest, intermediate, and lowest walking categories in relation to the outcome measures. Conclusions: The results suggest walking is inversely associated with clinical disease endpoints and largely support the current guidelines for physical activity. The mechanisms that mediate this relationship remain largely unknown and should be the focus of future research.

A bidirectional relationship between psychosocial factors and atopic disorders: A systematic review and meta-analysis.

Objective: There is growing epidemiological literature focusing on the bidirectional association between psychosocial factors and atopic disorders, but no efforts to quantify the relationship systematically have been published. Methods: We searched Medline, PsycINFO, Web of Science, and PubMed up to June 2007. The studies included were prospective cohort studies investigating the influence of psychosocial factors on atopic disorders and the effect of atopic disorders on mental health. Two investigators independently extracted data and determined study quality. Results: There were 43 studies (in 22 articles), of which 34 evaluated the effect of psychosocial factors on atopic disorders and 9 evaluated the effect of atopic disorders on mental health. The major atopic disease assessed in these studies was asthma (90.7%) with allergic rhinitis, 4.7%; atopic dermatitis, 2.3%; and food allergies, 2.3%. The overall meta-analysis exhibited a positive association between psychosocial factors and future atopic disorder (correlation coefficient (r) as combined size effect .024; 95% confidence interval, 0.014–0.035; p < .001) as well as between atopic disorders and future poor mental health (r = .044, 95% confidence interval, 0.021–0.067, p < .001). More notably, the subgroup meta-analysis on the healthy and atopic disorder populations showed psychosocial factors had both an etiological and prognostic effect on atopic disorders. Conclusions: The current review revealed a robust relationship between psychosocial factors and atopic disorders. This supports the use of psychological in addition to conventional physical and pharmacological interventions, in the successful prevention and management of atopic disorders. 95% CI = 95% confidence interval; r = correlation coefficient.