Sharon Toker

Burnout and risk of cardiovascular disease: evidence, possible causal paths, and promising research directions.

Burnout is characterized by emotional exhaustion, physical fatigue, and cognitive weariness, resulting from prolonged exposure to work-related stress. The authors review the accumulated evidence suggesting that burnout and the related concept of vital exhaustion are associated with increased risk of cardiovascular disease and cardiovascular-related events. The authors present evidence supporting several potential mechanisms linking burnout with ill health, including the metabolic syndrome, dysregulation of the hypothalamic-pituitary-adrenal axis along with sympathetic nervous system activation, sleep disturbances, systemic inflammation, impaired immunity functions, blood coagulation and fibrinolysis, and poor health behaviors. The association of burnout and vital exhaustion with these disease mediators suggests that their impact on health may be more extensive than currently indicated.

The Association Between Burnout, Depression, Anxiety, and Inflammation Biomarkers: C-Reactive Protein and Fibrinogen in Men and Women

Following the demonstrated association of employee burnout or vital exhaustion with several risk factors for cardiovascular disease (CVD) and CVD risk, the authors investigated the possibility that one of the mechanisms linking burnout with CVD morbidity is microinflammation, gauged in this study by high-sensitivity C-reactive protein (hs-CRP) and fibrinogen concentrations. Their sample included 630 women and 933 men, all apparently healthy, who underwent periodic health examinations. The authors controlled for possible confounders including 2 other negative affective states: depression and anxiety. In women, burnout was positively associated with hs-CRP and fibrinogen concentrations, and anxiety was negatively associated with them. In men, depression was positively associated with hs-CRP and fibrinogen concentrations, but not with burnout or anxiety. Thus, burnout, depression, and anxiety are differentially associated with microinflammation biomarkers, dependent on gender.

Burnout and risk of type 2 diabetes: a prospective study of apparently healthy employed persons.

Objective: This prospective study was designed to test the extent to which the onset of type 2 diabetes in apparently healthy individuals was predicted by burnout, a unique affective response to combined exposure to chronic stressors. Methods: The study participants were 677 employed men and women who were followed up for 3 to 5 years (mean = 3.6 years) for the onset of diagnosed type 2 diabetes. Burnout was assessed by the Shirom-Melamed Burnout Measure with its three subscales: emotional exhaustion, physical fatigue, and cognitive weariness. Results: The burnout symptoms were remarkably consistent over the follow-up period irrespective of changes in place of work and in employment status. During the follow-up period, 17 workers developed type 2 diabetes. Logistic regression results indicated that burnout was associated with a 1.84-fold increased risk of diabetes (95% confidence interval [CI] = 1.19–2.85) even after adjusting for age, sex, body mass index, smoking, alcohol use, leisure time physical activity, initial job category, and follow-up duration. In a subsample of 507 workers, the relative risk of diabetes was found to be much higher after additional control for blood pressure levels (odds ratio = 4.32, 95% CI = 1.75–10.67), available only for this subsample. Conclusions: These findings suggest that chronic burnout might be a risk factor for the onset of type 2 diabetes in apparently healthy individuals. CI = confidence interval; CVD = cardiovascular disease; SMBM = Shirom-Melamed Burnout Measure; HbA1c = glycosylated hemoglobin A1c; VE = vital exhaustion; MI = myocardial infarction; MBI = Maslach Burnout Inventory; BMI = body mass index; SBP = systolic blood pressure; DBP = diastolic blood pressure; OR = odds ratio; APR = acute phase response; CRP = C-reactive protein; HDL = high-density lipoprotein; HPA = hypothalamic–pituitary–adrenal.

Job Burnout and Depression: Unraveling Their Temporal Relationship and Considering the Role of Physical Activity

Job burnout and depression have been generally found to be correlated with one another. However, evidence regarding the job burnout-depression association is limited in that most studies are cross-sectional in nature. Moreover, little is known about factors that may influence the job burnout-depression association, other than individual or organizational factors (e.g., gender, supervisor support). The current study seeks to address these gaps by (a) unraveling the temporal relationship between job burnout and depression and (b) examining whether the job burnout-depression association may be contingent upon the degree to which employees engage in physical activity. On the basis of a full-panel 3-wave longitudinal design with a large sample of employees (N = 1,632), latent difference score modeling indicated that an increase in depression from Time 1 to Time 2 predicts an increase in job burnout from Time 2 to Time 3, and vice versa. In addition, physical activity attenuated these effects in a dose-response manner, so that the increase in job burnout and depression was strongest among employees who did not engage in physical activity and weakest to the point of nonsignificance among those engaging in high physical activity.

Heart rate and microinflammation in men: a relevant atherothrombotic link

Objective and background: To explore the possibility that increased resting heart rate (HR) is associated with a microinflammatory response. Such an association could explain, at least in part, the recently described worse cardiovascular prognosis in individuals with increased HR. Methods: Concentrations of fibrinogen and high-sensitivity C-reactive protein, as well as the absolute number of polymorphonuclear leucocytes, were analysed in a cohort of 4553 apparently healthy men and in those with atherothrombotic risk factors. Results: Following adjustment for age and body mass index, lipid profile and cardiovascular risk factors, a significant (p<0.001) difference was noted between individuals in the first quintile of HR (⩽58 beats/min) and those in the fifth quintile (⩾79 beats/min) regarding all the above-mentioned inflammatory biomarkers, the respective mean values being 7.38 and 8.11 μmol/l, 1.12 and 1.61 mg/l, and 4.23 and 4.74×109/l. Conclusions: Resting HR is associated with a microinflammatory response in apparently healthy men and in those with atherothrombotic risk factors. Sympathetic activation might be a common factor explaining such an association. If confirmed in additional studies, this association might be a relevant target for therapeutic manipulations.

The Effects of Physical Fitness and Feeling Vigorous on Self-Rated Health

OBJECTIVE We prospectively studied the hypothesized beneficial effects of feeling vigorous and of objective physical fitness (gauged based on functional capacity) on subsequently assessed self-rated health (SRH), controlling for possible confounders known to be precursors of SRH and of our predictors. We also investigated the reverse-causation hypothesis that SRH predicts subsequent vigor and functional capacity. DESIGN Participants were apparently healthy employees (N = 779) who underwent a routine health check at two points of time, Time 1 (T1) and Time 2 (T2), about 18 months apart. We used regression analysis, predicting T2 SRH by T1 SRH, the control variables, and T1vigor and functional capacity. MAIN OUTCOME MEASURES Vigor was assessed using the Shirom-Melamed Vigor Measure; objective physical fitness was indicated by functional capacity following a treadmill exercise, and self-rated health was measured by a single item. RESULTS As hypothesized, we found that the change in T2 SRH was positively predicted by T1 vigor, functional capacity, and their interactive term. Testing the reverse causation paths, we found that T1 SRH did not predict subsequent functional capacity and was a relatively weak predictor of subsequent vigor. CONCLUSION The affective state of vigor and objectively assessed functional capacity interact to predict subsequent changes in self-rated health.

Burnout and Risk of Coronary Heart Disease: A Prospective Study of 8838 Employees

Objective Burnout is a negative affective state consisting of emotional exhaustion, physical fatigue, and cognitive weariness symptoms. This study was designed to evaluate prospectively the association between burnout and coronary heart disease (CHD) incidence and to test the possibility that this association is nonlinear. Methods Participants were 8838 apparently healthy employed men and women, aged 19 to 67 years, who came for routine health examinations at the Tel Aviv Sourasky Medical Center. They were followed up for 3.4 years on average. Burnout was measured by the Shirom-Melamed Burnout Measure. CHD incidence was defined as a composite of acute myocardial infarction, diagnosed ischemic heart disease, and diagnosed angina pectoris. Results During follow-up, we identified 93 new cases of CHD. Baseline levels of burnout were associated with an increased risk of CHD, after adjustment for various risk factors (hazard ratio = 1.41; 95% confidence interval = 1.08–1.85). In addition, we observed a significant threshold effect of burnout on CHD incidence. Participants who scored high on burnout (scores in the upper quintile of the Shirom-Melamed Burnout Measure scores distribution) had a higher risk (hazard ratio = 1.79; 95% confidence interval = 1.05–3.04) of developing CHD on follow-up compared with others. Conclusions Burnout is an independent risk factor for future incidence of CHD. Individuals with high levels of burnout (upper quintile) have a significantly higher risk of developing CHD compared with those with low levels of burnout. Abbreviations CI = confidence interval CHD = coronary heart disease IHD = ischemic heart disease SMBM = Shirom-Melamed Burnout Measure BMI = body mass index ECG = electrocardiogram LDL = low-density lipoprotein

Association of fear of terror with low-grade inflammation among apparently healthy employed adults.

Objective: Based on evidence that psychological stress may induce a chronic inflammatory process, we hypothesized that the stress caused by chronic fear of terror may be associated with low-grade inflammation. This hypothesis was examined in employed men and women with the presence of low-grade inflammation measured by high sensitivity C-reactive protein (CRP). Methods: Apparently healthy employed adults (N = 1153) undergoing periodic health check-ups in a tertiary hospital in Israel completed a questionnaire. Fear of terror (scored 1–5) was assessed by three items measuring the extent to which respondents have deep concern for personal safety, elevated tension in crowded places, and fear of terror strikes causing harm to ones self or ones family members. The main outcome measure was the presence or absence of an elevated CRP level (>3.0 mg/L). Results: Women scored significantly higher on fear of terror compared with men (M = 2.16 vs. M = 1.68, respectively; p < .0001). Most of the study participants who scored high (4 or 5) on fear of terror, reported having experienced this feeling for 1 year or more. In women only, there was a positive association between fear of terror and risk of elevated CRP level (adjusted OR = 1.7, 95% CI 1.2–2.4) in a multivariate model adjusting for generalized anxiety, depressive symptoms, and potentially confounding demographic and biomedical variables. Conclusions: Chronic fear of terror in women, but not in men, is associated with elevated CRP levels, which suggests the presence of low-grade inflammation and a potential risk of cardiovascular disease.

Relation of Educational Level to Inflammation-Sensitive Biomarker Level

It is a well-established finding that cardiovascular morbidity varies among groups of different socioeconomic status. Inflammatory processes have been proposed as a possible mediator of this variance. Level of education is an important indicator of socioeconomic status, inversely related to levels of inflammatory biomarkers. Whether this association was significant in a subpopulation of highly educated individuals was questioned. This cross-sectional study enrolled attendees of an executive health screening program intended specifically for executive and high-wage personnel from September 2002 to November 2007. A detailed questionnaire, anthropometric measurements, and laboratory data were used to determine self-reported years of education and cardiovascular risk factors. Linear regression models included high-sensitivity C-reactive protein, fibrinogen, erythrocyte sedimentation rate, and white blood cell count as dependent variables and were adjusted for multiple potential confounders. Data for 8,998 subjects (5,757 men, 3,241 women) with a mean age of 44 years (range 18 to 84) were analyzed. More than two-thirds reported >or=14 years of schooling, and >2,900 reported >or=17 years of schooling. We found a statistically significant inverse association between number of school years and high-sensitivity C-reactive protein, fibrinogen, and erythrocyte sedimentation rate. Higher levels of education were associated with lower prevalences of diabetes and current smoking in both genders and lower prevalences of hypertension and dyslipidemia in women. In conclusion, level of education was inversely associated with inflammatory biomarkers and prevalence of cardiovascular risk factors, even within highly educated populations.

Feeling vigorous and the risks of all-cause mortality, ischemic heart disease, and diabetes: a 20-year follow-up of healthy employees.

Objective: To investigate prospectively the effects of vigor at work on the end points of mortality and the prevalence of ischemic heart disease (IHD) and diabetes. Methods: We tested the hypothesized beneficial effects of feeling vigorous at work at baseline on the risks of all-cause mortality, IHD, and diabetes during a 20-year follow-up. Participants were healthy employees (n = 968) who underwent a routine health check at baseline. We calculated the risk of all-cause mortality, IHD, and diabetes, with days as the time scale, using the Cox proportional hazard model. In our analyses, we predicted the above end points by baseline vigor, age, gender, and educational level, adjusting for the physiological risk factors of total cholesterol, glucose, and body mass index, the behavioral risk factors of smoking, alcohol intake, and physical activity, and the psychological risk factors of depressive and anxiety symptoms. Results: As hypothesized, we found that, after the above adjustments, baseline vigor decreased the risk of follow-up mortality by 26% (hazard ratio, 0.74; 95% confidence interval, 0.58–0.95) and the risk of diabetes by 17% (hazard ratio, 0.83; 95% confidence interval, 0.68–0.98). However, vigor did not have a significant effect on the risk of IHD. Conclusions: Independently of physiological, behavioral, and psychological risk factors, feeling vigorous at work protected the participants from diabetes and reduced their risk of mortality. IHD = ischemic heart disease; CHS = Clalit Health Services; BMI = body mass index; SES = socioeconomic status.