Robert Karasek

The Job Content Questionnaire (JCQ): an instrument for internationally comparative assessments of psychosocial job characteristics.

Part I discusses the Job Content Questionnaire (JCQ), designed to measure scales assessing psychological demands, decision latitude, social support, physical demands, and job insecurity. Part II describes the reliability of the JCQ scales in a cross-national context using 10,288 men and 6,313 women from 6 studies conducted in 4 countries. Substantial similarity in means, standard deviations, and correlations among the scales, and in correlations between scales and demographic variables, is found for both men and women in all studies. Reliability is good for most scales. Results suggest that psychological job characteristics are more similar across national boundaries than across occupations.

Job decision latitude, job demands, and cardiovascular disease: a prospective study of Swedish men.

The association between specific job characteristics and subsequent cardiovascular disease was tested using a large random sample of the male working Swedish population. The prospective development of coronary heart disease (CHD) symptoms and signs was analyzed using a multivariate logistic regression technique. Additionally, a case-controlled study was used to analyze all cardiovascular-cerebrovascular (CHD-CVD) deaths during a six-year follow-up. The indicator of CHD symptoms and signs was validated in a six-year prospective study of CHD deaths (standardized mortality ratio 5.0; p less than or equal to .001). A hectic and psychologically demanding job increases the risk of developing CHD symptoms and signs (standardized odds ratio 1.29, p less than 0.25) and premature CHD-CVD death (relative risk 4.0, p less than .01). Low decision latitude-expressed as low intellectual discretion and low personal schedule freedom-is also associated with increased risk of cardiovascular disease. Low intellectual discretion predicts the development of CHD symptoms and signs (SOR 1.44, p less than .01), while low personal schedule freedom among the majority of workers with the minimum statutory education increases the risk of CHD-CVD death (RR 6.6, p less than .0002). The associations exist after controlling for age, education, smoking, and overweight.

Current issues relating to psychosocial job strain and cardiovascular disease research.

: The authors comment on recent reviews of cardiovascular job strain research by P. L. Schnall and P. A. Landsbergis (1994), and by T. S. Kristensen (1995), which conclude that job strain as defined by the demand-control model (the combination of contributions of low job decision latitudes and high psychological job demands) is confirmed as a risk factor for cardiovascular mortality in a large majority of studies. Lack of social support at work appears to further increase risk. Several still-unresolved research questions are examined in light of recent studies: (a) methodological issues related to use of occupational aggregate estimations and occupational career aggregate assessments, use of standard scales for job analysis and recall bias issues in self-reporting; (b) confounding factors and differential strengths of association by subgroups in job strain-cardiovascular disease analyses with respect to social class, gender, and working hours; and (c) review of results of monitoring job strain-blood pressure associations and associated methodological issues.

Job characteristics in relation to the prevalence of myocardial infarction in the US Health Examination Survey (HES) and the Health and Nutrition Examination Survey (HANES).

Associations between psychosocial job characteristics and past myocardial infarction (MI) prevalence for employed males were tested with the Health Examination Survey (HES) 1960-61, N = 2,409, and the Health and Nutrition Examination Survey (HANES) 1971-75, N = 2,424. A new estimation method is used which imputes to census occupation codes, job characteristic information from national surveys of job characteristics (US Department of Labor, Quality of Employment Surveys). Controlling for age, we find that employed males with jobs which are simultaneously low in decision latitude and high in psychological work load (a multiplicative product term isolating 20 per cent of the population) have a higher prevalence of myocardial infarction in both data bases. In a logistic regression analysis, using job measures adjusted for demographic factors and controlling for age, race, education, systolic blood pressure, serum cholesterol, smoking (HANES only), and physical exertion, we find a low decision latitude/high psychological demand multiplicative product term associated with MI in both data bases. Additional multiple logistic regressions show that low decision latitude is associated with increased prevalence of MI in both the HES and the HANES. Psychological workload and physical exertion are significant only in the HANES.

Myocardial infarction risk and psychosocial work environment: An analysis of the male Swedish working force

The project was designed to test the assumption that certain psychosocial characteristics of occupational groups are associated with elevated myocardial infarction risk. All cases of myocardial infarction below the age of 65 in men living in the region of greater Stockholm during the years 1974-1976 were identified (deaths as well as survivals) in the official registries of hospitalizations and deaths. For each case two controls without infarction (in younger ages four) matched for age, area of residence and sex were selected randomly from the parish registries. For each case and control (n = 334 and 882, respectively) information was available regarding occupation. The psychosocial characteristics of each one of the 118 occupations were recorded by means of a nation wide interview survey (3876 working men) in 1977. Relative age-adjusted risks of developing a myocardial infarction were calculated for occupations in which many vs occupations in which few subjects reported a given characteristic (50% with most vs 50% with least). Shift work and monotony were associated with significant excess risk. Hectic work was not associated with excess risk by itself but in combination with variables associated with low decision latitude and/or few possibilities for growth it was associated with significant excess risk.

Physiology of Stress and Regeneration in Job Related Cardiovascular Illness

Abstract The possible physiological significance of individual control over environmental/occupational stressors has not been discussed systematically in relation to cardiovascular disease. In this paper we review associations between stressors and control in the work situation and endocrine, metabolic, and cardiovasclar activity, using the categories “anabolic” and “catabolic” to organize the findings in relation to the development of ischemic cardiovascular disease. We propose a comprehensive hypothesis, related to existing stress models which incorporates potential physiological regenerative or ameliorating—as well as pathologic—effects of stressor exposure. Regenerative processes are hypothesized to occur in circumstances where equilibrium or a match exists between environmental demands and possibilities for individual control over those demands, whereas pathologic consequences would occur when demands exceed control. This theory is further proposed to account for cardiovascular pathophysiologic diffe...

A procedure for linking psychosocial job characteristics data to health surveys.

A system is presented for linking information about psychosocial characteristics of job situations to national health surveys. Job information can be imputed to individuals on surveys that contain three-digit US Census occupation codes. Occupational mean scores on psychosocial job characteristics-control over task situation (decision latitude), psychological work load, physical exertion, and other measures-for the linkage system are derived from US national surveys of working conditions (Quality of Employment Surveys 1969, 1972, and 1977). This paper discusses a new method for reducing the biases in multivariate analyses that are likely to arise when utilizing linkage systems based on mean scores. Such biases are reduced by modifying the linkage system to adjust imputed individual scores for demographic factors such as age, education, race, marital status and, implicitly, sex (since men and women have separate linkage data bases). Statistics on the linkage systems efficiency and reliability are reported. All dimensions have high inter-survey reproducibility. Despite their psychosocial nature, decision latitude and physical exertion can be more efficiently imputed with the linkage system than earnings (a non-psychosocial job characteristic). The linkage system presented here is a useful tool for initial epidemiological studies of the consequences of psychosocial job characteristics and constitutes the methodological basis for the subsequent paper.

Covariation between workplace physical and psychosocial stressors: evidence and implications for occupational health research and prevention

There is increasing interest in distinguishing the effects of physical and psychosocial workplace stressors on the aetiology of work-related musculoskeletal disorders (MSD). Modest associations have been found between psychosocial stressors and MSD, such as intensive load, monotonous work and low job control. Interpretation of these results has been limited by likely covariation between physical and psychosocial stressors. This investigation examined exposure covariation among blue- and white-collar workers employed in a mass production manufacturing environment (N = 410). Physical stressors were assessed from questionnaire and accelerometry. Psychosocial stressors were assessed from questionnaire. Pearson and Spearman correlation coefficients were computed. An exploratory factor analysis procedure identified possible common factors linking specific physical and psychosocial stressors. Moderate to high correlations between some physical and psychosocial stressors showed evidence of covariation both across and within groups. Covariation was strongest among blue-collar production and low-status office workers. Factor analysis results showed considerable shared variance between some physical and psychosocial stressors, such as repetition and job control, suggesting that these disparate stressors manifest from common work organization factors that govern the structure of work. While recognizing the conceptual differences between physical and psychosocial stressors, these results call attention to the strong empirical relationships that can exist between some stressors in the workplace setting. To guard against ambiguous study findings that can occur when exposures are mixed, it is critical that future epidemiologic studies include information about the degree of association between task-level stressors. Future research on work organization determinants of task-level stressors, and their coincident occurrence in jobs with greater specialization, may provide promising new insights into the nature of risk for MSD and effective prevention strategies.

Job strain variations in relation to plasma testosterone fluctuations in working men - a longitudinal study

Abstract. Job strain, a high level of psychological demands combined with a low level of decision latitude, has been hypothesized to induce mobilization of energy and inhibition of anabolism. In the present project this hypothesis was tested using four repeated observations every third month in a group of 44 men working in six widely different occupations. On each occasion scores of self‐reported demands and decision latitude were calculated for every participant. An earlier report has shown that systolic blood pressure during work hours ‐ an indicator of mobilization of energy ‐ increased with increasing job strain (ratio between demands and decision latitude). Blood samples were drawn in the morning at the work site. For each man the plasma testosterone levels ‐ representing the general level of anabolic activity ‐ on the two occasions with the worst strain (ratio between demands and decision latitude) were compared with the plasma testosterone levels on the two occasions with the least strain. The results indicated that total plasma testosterone (but not free testosterone) levels increased when strain diminished in sedentary but not in physically demanding work. Subjects with a family history of hypertension showed a greater decrease in testosterone levels than others when job strain increased.

Sedentary work, low physical job demand, and obesity in US workers

BACKGROUND Little is known about the role of low physical activity at work (sedentary work or low physical job demand) in the increasing prevalence of obesity of US workers. METHODS This cross-sectional and secondary data analysis included 1,001 male and 1,018 female workers (age range: 32-69) from the National Survey of Midlife Development in the United States (MIDUS) II study (2004-2006). Sedentary work and physical job demand were measured by questionnaire items. Total obesity (based on body mass index) and central obesity (based on waist circumference) were defined using WHO criteria. RESULTS After controlling for covariates (socio-demographic, psychosocial working conditions, health status, and health behaviors), sedentary work, low physical job demand, or their combination increased the risk for total and central obesity in male workers, particularly when they worked longer than 40 hr per week. Sedentary work marginally increased the risk for total and central obesity in female workers. CONCLUSIONS Low physical activity at work is a significant risk factor for total and central obesity in middle-aged US male workers.