Chronic work stress is associated with atherogenic lipids and elevated fibrinogen in middle-aged men

Influence of socioeconomic status and job control on plasma fibrinogen responses to acute mental stress

OBJECTIVE

An elevation in plasma fibrinogen may be one of the pathways through which low socioeconomic status increases cardiovascular disease risk. This study assessed the influence of socioeconomic status, job control, and social isolation on fibrinogen responses to acute stress.

METHODS

The study was conducted with 125 white men and 96 white women aged 47 to 58 years, drawn from the Whitehall II cohort. Socioeconomic status was indexed by grade of employment, with 82 high, 75 intermediate, and 64 low grade participants. Plasma fibrinogen and hematocrit were assessed at baseline, immediately after performance of color-word and mirror tracing tasks, and 45 minutes later.

RESULTS

Plasma fibrinogen increased from baseline to stress (from 2.85 +/- 0.57 to 2.92 +/- 0.58 g/liter), remaining elevated 45 minutes after stress (2.89 +/- 0.58 g/liter, p <.001). Fibrinogen concentration was greater in the low than in the high or intermediate employment grade groups, independently of sex, age, body mass index, smoking status, and hematocrit. Fibrinogen responses to acute stress did not differ across employment grades. Women had higher fibrinogen levels than men, but this pattern was abolished in women taking hormone replacement therapy. Men experiencing low job control showed greater fibrinogen responses to acute stress than did those with high job control (p =.003). Fibrinogen levels were greater in socially isolated individuals, but social isolation did not affect responses to acute stress.

CONCLUSIONS

Socioeconomic status and acute stress had independent effects on the plasma fibrinogen level. Low job control may influence cardiovascular disease risk in men partly through provoking greater fibrinogen stress responses.

When reciprocity fails: effort-reward imbalance in relation to coronary heart disease and health functioning within the Whitehall II study

BACKGROUND

A deleterious psychosocial work environment, as defined by high efforts expended in relation to few rewards reaped, is hypothesised to increase the risk of future poor health outcomes.

AIMS

To test this hypothesis within a cohort of London based civil servants.

METHODS

Effort-reward imbalance (ERI) was measured among 6895 male and 3413 female civil servants aged 35-55 during the first phase of the Whitehall II study (1985-88). Participants were followed until the end of phase 5 (1997-2000), with a mean length of follow up of 11 years. Baseline ERI was used to predict incident validated coronary heart disease (CHD) events during follow up and poor mental and physical functioning at phase 5.

RESULTS

A high ratio of efforts in relation to rewards was related to an increased incidence of all CHD (hazard ratio (HR) = 1.36, 95% CI 1.12 to 1.65) and fatal CHD/non-fatal myocardial infarction (HR = 1.28, 95% CI 0.89 to 1.84) during follow up, as well as poor physical (odds ratio (OR) = 1.47, 95% CI 1.24 to 1.74) and mental (OR = 2.24, 95% CI 1.89 to 2.65) functioning at phase 5, net of employment grade. A one item measure of high intrinsic effort also significantly increased the risk of these health outcomes, net of grade. ERI may be particularly deleterious with respect to CHD risk among those with low social support at work or in the lowest employment grades.

DISCUSSION

Within the Whitehall II study, a ratio of high efforts to rewards predicted higher risk of CHD and poor physical and mental health functioning during follow up. Although the increased risk associated with ERI was relatively small, as ERI is common it could be of considerable public health importance.

Occupational stress and work-related upper extremity disorders: concepts and models

BACKGROUND

While research has suggested that interventions targeted at occupational stress (job stress) factors may improve clinical and work outcomes related to work-related musculoskeletal disorders, the emerging hypotheses relating occupational stress to work-related upper extremity disorders (WRUEDs) are not particularly well known among occupational health providers and researchers.

METHODS

Generic job stress and health models and multivariable models of WRUEDs were described and evaluated.

RESULTS

Models on occupational stress and health/WRUEDs offer unique perspectives on the role of occupational stressors on WRUEDs. However, the limited support for the structure and proposed mechanisms of these models suggest that investigations examining and validating proposed biobehavioral pathways are still needed.

DISCUSSION

Difficulties in conceptualizing occupational stress have, in the past, hindered its systematic incorporation into occupational health research and prevention/intervention strategies. The present paper provides a common basis for researchers and practitioners with diverse backgrounds to understand job stress and its relation to WRUEDs in order to enhance future efforts. Given the present limitations in the field and the need for comprehensive approaches to WRUEDs, there is great potential for occupational health researchers and clinicians to advance knowledge in this area.

Responsiveness of measures in the effort-reward imbalance questionnaire to organizational changes: a validation study

OBJECTIVE

To examine the responsiveness of measures adopted in the effort-reward imbalance (ERI) questionnaire to organizational changes.

METHOD

For the employees who had been affected by restructuring of their company due to the economic hardship, two consecutive questionnaire surveys were conducted over a specific period. A total of 544 full-time employees responded to both surveys. Changes in four summary measures from the situation-specific model component and the person-specific component, and items/subscales that constitute the questionnaire were evaluated.

RESULTS

The summary measures on psychological deterioration in the total study population. The deterioration was prevalent in those employees who had presumably experienced the effects of stressful organizational changes related to the restructuring, while improvement in the summary measures was observed for those employees who were promoted during the period. On the whole, the measures for the items of the situation-specific component and subscales for the personal component changed in the expected direction. With regard to ERI, potentially stronger effects of multiple organizational changes on employees were indicated.

CONCLUSION

Measurements of ERI at work are valid in terms of responsiveness to organizational changes.

[A sense of responsibility in health personnel as a cause of work-related stress]

INTRODUCTION

Job stress is a great problem in developed countries of the world, but in Yugoslavia, it is increased due to additional reasons associated with economic crisis in the society. Health services and health workers are in particularly difficult conditions. The aim of this paper was to examine sources and causes of job stress in health workers.

MATERIAL AND METHODS

The research was undertaken among health workers treated at Health Centre "Hospital" in Novi Sad. The study group included health workers--doctors, nurses and laboratory workers, and the control group included the rest of non-medical staff. Adapted Siegrist questionnaire was used. Three factors were examined: extrinsic efforts (disturbances at work, sense of great job responsibility and the need for overtime work); intrinsinc efforts (major criticism, thinking about the job from the early morning, getting nervous because of minor problems, discontentment because of unsolved problems at work, relaxation at home and so on), and low reward (respect from the superiors and colleagues, support and security at workplace). Answers were scored indicating intensity (high, moderate, low, not at all). Statistic analysis included testing the level of significance in health workers in relation to non-medical staff (t test and Fisher's exact test).

RESULTS

Applying the scoring system it has been established that health workers are exposed to greater job stress, great sense of very high job responsibility and frequent overtime work (p < 0.001) than the control group. In regard to answers from the second group--intrinsic effort and low reward, there was no statistiscal significance between the study and control group. Generally, high level of risk factors was established, especially presence of one or more risk factors.

DISCUSSION

Job stress increases absenteeism, reduces work productivity, causes higher expenses of medical treatment, rehabilitation and staff retraining. It is of great importance to identify factors which cause job dissatisfaction in order to decrease them to the lowest level.

CONCLUSION

High sense of responsibility in health workers is a course of job stress.

Inflammation and coagulation factors in persons > 65 years of age with symptoms of depression but without evidence of myocardial ischemia

Depression is associated with increased cardiovascular disease, but the underlying mechanisms are not well understood. This study examines associations of depressive symptoms with inflammation and coagulation factors in persons aged > 65 years. Blood samples were obtained from 4,268 subjects free of cardiovascular disease (age 72.4 +/- 5.5 years, 2,623 women). Inflammation markers were C-reactive protein (CRP), white blood cell (WBC) count, total platelet count, and albumin; coagulation factors included factors VIIc and VIIIc and fibrinogen. Depression was assessed with the Center for Epidemiologic Studies Depression scale, and states of energy depletion with a validated exhaustion index. Statistical adjustments were made for risk factors (age, sex, race, systolic blood pressure, smoking status, diabetes mellitus) and physical measures of frailty (isometric handgrip, timed 15-feet walk test, activity level). Depression was associated with elevated CRP (3.31 +/- 0.10 vs 3.51 +/- 0.21 mg/L), WBC (6.14 +/- 0.03 vs 6.43 +/- 0.11 10(6)/L), fibrinogen (319 +/- 1 vs 326 +/- 3 mg/dl), and factor VIIc (124.6 +/- 0.6% vs 127.2 +/- 1.3%; all p <0.05). Exhaustion also was related to elevated inflammation and coagulation markers (p < 0.05). Exhausted men had markedly elevated CRP levels (6.82 +/- 2.10 mg/L) versus nonexhausted men (3.05 +/- 0.16: p = 0.007). After adjustment for control variables, exhaustion remained associated with albumin (p = 0.033), fibrinogen (p = 0.017), CRP (p = 0.066), and WBC (p = 0.060), whereas associations of depressive symptoms with biochemistry measures lost statistical significance. Thus, depression and exhaustion are associated with low-grade inflammation and elevated coagulation factors in persons aged > 65 years.

Effects of psychological stress and psychiatric disorders on blood coagulation and fibrinolysis: a biobehavioral pathway to coronary artery disease?

OBJECTIVE

A hypercoagulable state before overt thrombosis resulting from an imbalance between the coagulation and fibrinolysis systems is related to cardiovascular disease progression and acute coronary syndromes. Psychological stressors and depressive and anxiety disorders also are associated with coronary artery disease. This review explores whether changes in blood coagulation, anticoagulant, and fibrinolytic activity may constitute psychobiological pathways that link psychological factors with coronary syndromes.

METHODS

Literature on coagulation, anticoagulation, and fibrinolysis measures in conjunction with psychological factors (mental stress, psychosocial strain, and psychiatric disorders) was identified by MEDLINE search back to 1966 and through checking the bibliographies of these sources. Sixty-eight articles were critically reviewed.

RESULTS

In healthy subjects, acute mental stress simultaneously activates coagulation (ie, fibrinogen or von Willebrand factor) and fibrinolysis (ie, tissue-type plasminogen activator) within a physiological range. In patients with atherosclerosis and impaired endothelial anticoagulant function, however, procoagulant responses to acute stressors may outweigh anticoagulant mechanisms and thereby promote a hypercoagulable state. Chronic psychosocial stressors (job strain or low socioeconomic status) are related to a hypercoagulable state reflected by increased procoagulant molecules (ie, fibrinogen or coagulation factor VII) and by reduced fibrinolytic capacity. There is also some evidence that points to hypercoagulability in depression.

CONCLUSIONS

Different categories of psychological measures to varying extent are associated with characteristic patterns of coagulation and fibrinolysis activity. Associations between psychological factors and several coagulation and fibrinolysis variables related to atherosclerosis provide a plausible biobehavioral link to coronary artery disease.

Biological correlates of social support and pressure at work in managers

The aim was to explore the patterns of correlations between psychosocial stress indices and neuroendocrinological factors in managers. Fifty-eight male managers in three Swedish companies constituted the sample. They answered two questionnaires with 17 selected stress indices and also an organizational test. The indices have been analyzed by means of computations of age adjusted partial correlations with nine different variables analyzed in fasting blood samples. The serum concentrations of lipids were the variables most strongly correlated with psychosocial factors. Neither smoking nor physical activity changed the correlations significantly. Good social support at work and in private life was consistently associated with low adverse serum lipids and corresponding lipoproteins. On the other hand, some indices of social support were associated with indices of high arousal levels. This may indicate a possible psychophysiological "load effect" of some aspects of social support in managers. The analyses of corporate culture measured as "Rules of the Game" indicated that "bureaucracy" was significantly associated with high LDL-cholesterol and low HDL-cholesterol. Managers have special conditions and therefore the patterns of associations between psychosocial conditions and coping strategies on one hand and endocrine-biochemical state on the other hand may be different from those of other groups. To what extent such differences are due to individual characteristics or environmental factors needs to be further investigated. According to the results, however, good social support is in general health promoting also to managers, at least with regard to serum lipids. Bureaucracy, on the other hand, seems to be dangerous to the health of managers.

Psychological factors associated with coronary heart disease

Objectives: Psychological coronary-proncncss is most probably one of the first recognised risk factors for coronary heart disease (CHD). The mechanisms by which psychological risk factors might exert their influence on the cardiovascular system arc less clear than those for the more standard biological risk factors. The aim of this review was to classify all possible mechanisms of potentiation of CHD by psychological factors.

Method: A MEDLINE search was conducted by selecting literature on both standard biological risk factors (eg. dyslipidaemia, hypertension, smoking) and psychological risk factors (eg. personality traits, behavioural characteristics, coping with stress) for CHD.

Results: It was suggested that six biological mechanisms could mediate psychological influences specifically for CHD, of course, together with the seventh mechanism of general alterations in health-related behaviours. These are: increased oxygen demand of the heart muscle, decreased blood supply to the heart muscle, increased concentration of blood, enhanced blood clotting, increase in cholesterol and other plasma lipids, disturbances of blood sugar level, and alterations in health-related behaviours.

Conclusions: If more studies of CHD were conducted with both physical and psychological risk factors simultaneously, it would be possible to investigate which of the above suggested mechanisms are important, which could in turn substantially improve both primary and secondary preventive measures.

Job strain and risk indicators for cardiovascular disease in young female nurses

This study examined the possible effects of job demands, decision latitude, and job-related social support on risk indicators for cardiovascular disease (CVD) in 165 female nurses. Job strain was measured with the Job Content Questionnaire; CVD risk was measured with insulin, total cholesterol, triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), fibrinogen, tissue-type plasminogen activator (tPA) antigen, tPA activity, plasminogen activator inhibitor-1 antigen, and blood pressure. Multivariate analysis of covariance and regression analyses revealed no effects of either job strain or social support on these risk indicators. All risk indicators deteriorated with age and body mass index. Oral contraceptive use improved fibrinolytic potential and increased HDL-C but had adverse effects on TG levels. Results suggest that in healthy young women job strain is not associated with an unfavorable metabolic or fibrinolytic risk profile.

The relationship between employment grade and plasma fibrinogen level among Japanese male employees. YKKJ Research Group

Plasma fibrinogen is an important risk factor for cardiovascular disease, and is associated with socioeconomic status in Europe and the United States. We evaluated whether the relationship between socioeconomic status and plasma fibrinogen level exists in Japanese male employees, and whether this relationship is independent of other correlates of plasma fibrinogen. This cross-sectional study was conducted on full-time male employees aged 20-58 in a metal-products factory between April 1996 and March 1997. Altogether 4375 employees (92.9%) participated. Low employment grade and low educational background were associated with increased age-adjusted plasma fibrinogen level. Adjusting for body mass index, waist to hip ratio, height, smoking habit, alcohol consumption, physical activity at leisure and systolic blood pressure did not attenuate these associations much. Adjusting for white blood cell count and hemoglobin Alc reduced the associations of both employment grade and educational background with plasma fibrinogen level, nevertheless these relationships remained significant.

Work stress and metabolic and hemostatic risk factors

OBJECTIVE

A high level of work stress has been associated with cardiovascular disease. However, the pathophysiological mechanisms underlying this association remain unclear. This study examined the effect of work stress on a cluster of metabolic and hemostatic risk factors.

METHODS

Blood was collected three times, on the first, third, and fifth day of a work week, from 124 middle-aged, white-collar workers. Metabolic measures were insulin, glucose, triglycerides, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, and total cholesterol. Hemostatic measures were fibrinogen, tissue-type plasminogen activator activity, tissue-type plasminogen activator antigen, and type 1 plasminogen activator inhibitor antigen. Chronic work stress was defined according to Siegrist's model as 1) a combination of high effort and low reward at work (effort-reward imbalance) or 2) high overcommitment (an exhaustive work-related coping style).

RESULTS

Overcommitment, but not imbalance or the imbalance-overcommitment interaction, was associated with an impaired fibrinolytic system, as reflected in decreased tissue-type plasminogen activator activity levels and increased type 1 plasminogen activator inhibitor antigen levels on all three measurement occasions. After controlling for body mass index, total cholesterol, triglycerides, high-density lipoprotein/low-density lipoprotein cholesterol ratio, glucose, and insulin, the relation between overcom-mitment and the fibrinolytic factors was attenuated but remained significant.

CONCLUSIONS

The results suggest that individuals with an exhaustive coping style at work have an impaired fibrinolytic capacity that is possibly due to the effects of chronic stress on insulin resistance.

Glycated hemoglobin as an indicator of social environmental stress among indigenous versus westernized populations

BACKGROUND

This study assessed whether glycated hemoglobin concentration, an indicator of psychogenic stress, differs between indigenous populations and non-indigenous reference groups.

METHODS

Multivariate and stratified analyses were undertaken of cross-sectional data from multi-center community-based diabetes diagnostic and risk factor screening initiatives in Canada and Australia. Population groups were Australian Aborigines (n = 116), Torres Strait Islanders (n = 156), Native Canadians (n = 155), Greek migrants to Australia (n = 117), and Caucasian Australians (n = 67). Measurements included fasting glycated hemoglobin (HbA(1c)) concentration, fasting and 2-h post-load glucose concentrations, body mass index, waist-to-hip ratio, and demographic variables.

RESULTS

Mean HbA(1c) concentrations were greater for indigenous groups than for Greek migrants and Caucasian Australians (P < 0. 0001). The covariate adjusted indigenous versus non-indigenous difference (95% CI) was 0.90 (0.58-1.22) percentage units, 18.2% higher for indigenous people. Stratified analyses indicated greater HbA(1c) for indigenous than for non-indigenous persons with normoglycemia (P = 0.009), impaired glucose tolerance (P = 0.097), and diabetes (P < 0.0001).

CONCLUSIONS

HbA(1c) concentrations are greater for indigenous than for non-indigenous groups. Social changes, low control, and living conditions associated with westernization may be inherently stressful at the biological level for indigenous populations in westernized countries.

Excess catecholamine syndrome. Pathophysiology and therapy

In addition to genetic factors, lifestyle has a predominant influence on primary hypertension and noninsulin-dependent diabetic mellitus (NIDDM). We initiated studies using radiotelemetry for characterizing molecular events linked with excess calorie intake and psychologic stress. An increased calorie intake was associated with raised (p < 0.05) systolic and diastolic blood pressure as well as heart rate independent of day-night cycle. Sympathetic activity was in excess when related to the unchanged motility. The hyperkinetic hypertension is expected to result in adverse remodeling of resistance vessels and to aggravate insulin resistance. To examine adverse effects of psychological stress, rats were subjected to intermittent food pellet feeding. Urinary catecholamines and cardiac norepinephrine stores were increased (p < 0.05). The depressed (p < 0.05) rate of Ca2+ uptake of sarcoplasmic reticulum is expected to contribute to cellular Ca2+ overload. These lifestyle influences strengthen the notion of an excess catecholamine syndrome which requires selective reduction of sympathetic outflow of the brain by I1-receptor agonists.

High effort, low reward, and cardiovascular risk factors in employed Swedish men and women: baseline results from the WOLF Study

STUDY OBJECTIVE

To examine associations between measures of work stress (that is, the combination of high effort and low reward) and cardiovascular risk factors.

DESIGN

Cross sectional first screening of a prospective cohort study.

SETTING AND PARTICIPANTS

The study was conducted among 5720 healthy employed men and women living in the greater Stockholm area aged 19-70 years. All analyses were restricted to subjects with complete data (n = 4958). The investigation of associations between indicators of effort-reward imbalance and cardiovascular risk factors was restricted to the age group 30-55 years (n = 3427).

MAIN RESULTS

Subjects reporting high effort and low reward at work had a higher prevalence of well known risk factors for coronary heart disease. After adjustment for relevant confounders, associations between a measure of extrinsic effort and reward (the effort-reward ratio) and hypertension (multivariate prevalence odds ratio (POR) 1.62-1.68), increased total cholesterol (upper tertile 220 mg/dl)(POR = 1.24) and the total cholesterol/high density lipoprotein(HDL)-cholesterol ratio (upper tertile 4.61)(POR 1.26-1.30) were found among men. Among women a measure of high intrinsic effort (immersion) was related to increased low density lipoprotein (LDL)-cholesterol (upper tertile 130 mg/dl)(POR 1.37-1.39). Analyses of variance showed increasing mean values of LDL cholesterol with an increasing degree of the effort-reward ratio among men and increased LDL-cholesterol among women with high levels of intrinsic effort (upper tertile of immersion).

CONCLUSIONS

Findings lend support to the hypothesis that effort-reward imbalance represents a specific constellation of stressful experience at work related to cardiovascular risk. The relation was not explained by relevant confounders (for example, lack of physical exercise, body weight, cigarette smoking).

Effects of moxonidine on stress-induced peak blood pressure and renal function: a randomized, double-blind, placebo-controlled crossover study

Moxonidine is an imidazoline I1-receptor agonist that centrally acts by reducing the sympathetic tone. Furthermore, proximal tubular I1-receptors have been isolated in human kidneys, but their natriuretic effects have never been demonstrated. Because stress tests elicited a sympathetically mediated increase in blood pressure and in sodium reabsorption, the aim of this study was to assess the effects of moxonidine (0.4 mg/day; 1 month) on stress-induced cardiovascular response and renal sodium handling in hypertensives, in a double-blind, crossover, placebo-controlled study. The stress test used is an efficient and reproducible computerized version of Stroop's stress test. During the experimental sessions, both rest and stress renal functional parameters were determined: glomerular filtration rate (inulin clearance), renal plasma flow (para-aminohippurate clearance), filtration fraction, sodium excretion, and segmental sodium tubular reabsorption (lithium clearance). During the placebo phase, stress induced a significant increase in systolic blood pressure (deltaSBP; 15.8+/-10.7 mm Hg) and diastolic blood pressure (deltaDBP; 8.2+/-6.1 mm Hg). During stress, glomerular filtration rate tended to decrease, whereas renal plasma flow significantly decreased, resulting in a significant increase in filtration fraction. Despite the increase in BP, stress induced a decrease in sodium excretion that was mainly due to a nonsignificant increase in sodium reabsorption in the proximal parts of the tubules. Moxonidine significantly reduced rest and stress BP, but the stress cardiovascular reactivity was not altered. At rest, renal function was well preserved by the treatment. Stress-induced modifications in renal function and sodium handling were not altered by the treatment. In conclusion, moxonidine reduced rest and stress-induced peak BP and preserved basal renal function. The study failed to demonstrate any effect of moxonidine either on basal renal sodium handling or on stress-induced increase in sodium reabsorption.