Schnall PL, Schwartz JE, Landsbergis PA, Warren K, Pickering TG. A longitudinal study of job strain and ambulatory blood pressure: Results from a three-year follow-up. Psychosomatic Medicine 1998;60:697-706.
Abstract
Objective: This study was conducted to investigate the hypothesis that exposure to "job strain" is related to increased ambulatory blood pressure (ABP).
Method: Participants were 195 men who wore an ABP monitor for 24 hours on two occasions 3 years apart. Job strain status, evaluated at each assessment, was used to identify four groups: those not having job strain at either assessment (N=138), those having job strain at both times (N=15), and the two crossover groups. Regression analysis was used to examine the cross-sectional associations of ABP change with category of job strain change.
Results: The cross-sectional analysis of the Time 2 data yielded almost identical, highly significant effects of job strain on ABP as was shown in our previously published Time 1 analysis. Those in high strain jobs at both times had systolic/diastolic ABPs at work and at home that were, on average, 11/7 mm Hg higher than those with no job strain at both times; the crossover groups had intermediate levels of ABP. The longitudinal analysis showed that those with a high strain job at Time 1, but not at time 2, had a significant decrease in work and home ABP of approximately 5/3 mm Hg.
Conclusions: The previously reported cross-sectional association between job strain and ABP was replicated at follow-up. The group repeatedly exposed to job strain had higher levels of ABP at Time 2 than either crossover group. Furthermore, change in job strain status partially predicted change in ABP. These results provide new evidence supporting the hypothesis that job strain is an occupational risk factor in the etiology of essential hypertension.
Pickering TG; Devereux RB; James GD; Gerin W; Landsbergis P; Schnall PL; Schwartz JE. Environmental influences on blood pressure and the role of job strain. J Hypertens Suppl 1996 Dec;14(5):S179-85.
ABSTRACT:
OBJECTIVE: To review the evidence that human essential hypertension
is at least in part the result of the influence of psychosocial
factors, with special reference to occupational stress (job strain).
FINDINGS: The prevalence of human hypertension is related to social
factors such as urbanization and education. Several studies, conducted
both experimentally in animals and observationally in people,
have suggested that chronic social conflict is associated with
higher blood pressure. Ambulatory monitoring has shown that most
people have their highest pressures during working hours. Occupational
stress can be evaluated as job strain, which is a combination
of high demands at work with low decision latitude or control.
Job strain has been related to coronary heart disease, and a number
of studies have shown that it is also associated with higher ambulatory
blood pressures, both cross-sectionally and prospectively, in
men but not in women. Men in high strain jobs also show an increased
left ventricular mass. Laboratory studies of blood pressure reactivity
to stressful tasks support the concept of loss of control being
associated with higher pressures.
CONCLUSIONS: Job strain is a risk factor for hypertension in men,
but not in women.
Schnall PL; Landsbergis PA; Baker D. Job strain and cardiovascular disease. Annu Rev Public Health 1994;15:381-411.
Landsbergis PA; Schnall PL; Warren K; Pickering TG; Schwartz JE. Association between ambulatory blood pressure and alternative formulations of job strain. Scand J Work Environ Health 1994 Oct;20(5):349-63.
ABSTRACT:
OBJECTIVES--The goal of the study was to determine whether
alternative formulations of Karasek & Theorell's job-strain
construct are associated with ambulatory blood pressure and the
risk of hypertension.
METHODS--Full-time male employees (N = 262) in eight worksites
completed a casual blood pressure screening, medical examinations,
and questionnaires and wore an ambulatory blood pressure monitor
for 24 h on a workday. Cases of hypertension were ascertained
from casual blood pressure readings for a case-referent analysis.
A cross-sectional analysis was also conducted, ambulatory (continuous)
blood pressure measurements being used as the outcome.
RESULTS--All formulations of job strain exhibited significant
associations with systolic blood pressure at work and home, but
not with diastolic blood pressure. Employees experiencing job
strain had a systolic blood pressure that was 6.7 mm Hg (approximately
0.89 kPa) higher and a diastolic blood pressure that was 2.7 mm
Hg (approximately 0.36 kPa) higher at work than other employees,
and the odds of hypertension were increased [odds ratio (OR) 2.9,
95% confidence interval (95% CI) 1.3-6.6]. Using national means
for decision latitude and demands to define job strain increased
the systolic and diastolic blood pressure associations to 11.5
mm Hg (approximately 1.53 kPa) and 4.1 mm Hg (approximately 0.54
kPa), respectively. Adding organizational influence to the task-level
decision latitude variable produced a stronger association for
hypertension with job strain (OR 3.7, 95% CI 1.6-8.5). Adding
social support to the job-strain model also slightly increased
the hypertension risk.
CONCLUSIONS--The impact of job strain, at least on systolic blood
pressure, is consistent and robust across alternative formulations,
more restrictive cut points tending to produce stronger effects.
Landsbergis PA; Schnall PL; Deitz D; Friedman R; Pickering TA. The patterning of psychological attributes and distress by "job strain" and social support in a sample of working men. J Behav Med 1992 Aug;15(4):379-405.
ABSTRACT:
As a test of the "job strain" (job demands-control) model, 297 healthy men aged 30-60 were recruited at eight New York City worksites. The association among job demands and control, social support, and psychological outcomes was tested using both ANCOVA and moderated multiple regression, controlling for demographic variables. The job strain model was supported by various psychological outcome measures, with workers in "active" jobs reporting the highest level of Type A behavior, job involvement, and positive attributional style, workers in "low-strain" jobs reporting the lowest job dissatisfaction and trait anxiety, workers in "passive" jobs reporting the most external locus of control and trait anxiety, and workers in "high-strain" jobs reporting the highest job dissatisfaction. Low social support was associated with greater symptomatology, and a significant three-way interaction (demands x control x support) for job dissatisfaction was observed. While selection of subjects into jobs may partially explain these findings, the results support the hypothesis that working conditions influence psychological attributes and distress.
Schnall PL; Landsbergis PA; Pieper CF; Schwartz J; Dietz D; Gerin W; Schlussel Y; Warren K; Pickering TG. The impact of anticipation of job loss on psychological distress and worksite blood pressure. Am J Ind Med 1992;21(3):417-32.
ABSTRACT:
The impact of occupational stressful life events on psychological distress and blood pressure was examined among employees of a major New York City brokerage firm undergoing massive layoffs. One hundred thirty-nine employees of the firm, who had participated in a blood pressure screening in 1986, were rescreened during the period of layoffs within their company in 1989. About two-thirds of the 139 employees reported being "somewhat" or "very" anxious or upset in 1989 during the period of layoffs, and psychological distress was significantly elevated among those employees reporting possible or definite layoff or job change and/or difficulty in obtaining a comparable job. However, we found no increase in overall blood pressure level, and no effect of anticipation of job loss on 1989 blood pressure when controlling for 1986 blood pressure level, age, body mass index, work hours, and other demographic variables. On the other hand, employment in a department sold to another employer on the day of screening, as well as employment in a clerical job title, were both associated with significant increases in diastolic blood pressure of about 5 mm Hg.
Schnall PL; Schwartz JE; Landsbergis PA; Warren K; Pickering TG. Relation between job strain, alcohol, and ambulatory blood pressure. Hypertension 1992 May;19(5):488-94.
ABSTRACT:
"Job strain" (defined as high psychological demands and low decision latitude on the job) has been previously reported to be associated with increased risk of hypertension and increased left ventricular mass index (LVMI) in a case-control study of healthy employed men, aged 30-60 years, without evidence of coronary heart disease. We hypothesized that job strain would be associated with increased ambulatory blood pressure (AmBP). A total of 264 men at eight work sites wore an AmBP monitor for 24 hours on a working day. In an analysis of covariance model, job strain was associated with an increase in systolic AmBP of 6.8 mm Hg (p = 0.002) and diastolic AmBP of 2.8 mm Hg at work (p = 0.03) after adjusting for age, race, body mass index, Type A behavior, alcohol behavior, smoking, work site, 24-hour urine sodium, education, and physical demand level of the job. Alcohol use also had a significant effect on AmBP. However, among subjects not in high-strain jobs, alcohol had no apparent effect on AmBP at work. Instead, alcohol use and job strain interacted such that workers in high-strain jobs who drank regularly had significantly higher systolic AmBP at work (p = 0.007). Among the other risk factors, only age, body mass index, and smoking had significant effects on AmBP. Job strain also had significant effects on AmBP at home and during sleep as well as on LVMI.
Pickering TG; Schnall PL; Schwartz JE; Pieper CF. Can behavioural factors produce a sustained elevation of blood pressure? Some observations and a hypothesis. J Hypertens Suppl 1991 Dec;9(8):S66-8.
ABSTRACT:
A major problem confronting behavioural theories of hypertension, such as the reactivity hypothesis, is that stress is likely to be intermittent, whereas the early stages of hypertension appear to be characterized by an increase in the tonic level of blood pressure and sympathetic activity. Furthermore, intermittent sympathetic arousal (e.g. exercise, thigh-cuff compression) does not necessarily raise tonic blood pressure. A worksite-based study of occupational stress has indicated that people in high-stress jobs have increased blood pressure throughout the day and night, which is at least consistent with a behaviourally mediated resetting of the tonic blood pressure level. There is evidence that adrenaline is preferentially released in response to behavioral stresses. According to the 'adrenaline hypothesis', adrenaline can raise tonic blood pressure while noradrenaline does not. We therefore propose that the different long-term effects of behavioural stress and exercise on blood pressure can be explained by their differing effects on catecholamine release.
Schlussel YR; Schnall PL; Zimbler M; Warren K; Pickering TG. The effect of work environments on blood pressure: evidence from seven New York organizations. J Hypertens 1990 Jul;8(7):679-85.
ABSTRACT:
The prevalence of hypertension defined according to National Health and Nutrition Examination Survey II (NHANES II) criteria (140/90 mmHg and/or taking antihypertensive medication) was analyzed cross-sectionally at seven worksites in New York City (n = 4274; 2616 men and 1648 women), in order to assess whether exposure to different work environments and occupations contributes to blood pressure variation. The prevalence of hypertension across worksites was 26% among men and 12% among women. Blood pressure was significantly different across worksites even after controlling for known risk factors using analysis of covariance. Of the variation in systolic pressure, 34% was predicted significantly by eight variables; after adjusting for upper-arm circumference, age and body mass index, higher pressures were associated with worksite differences (9.0 mmHg), being male (7.2 mmHg), lacking a high-school education (4.3 mmHg), having a clerical occupation (2.9 mmHg) and being unmarried (1.8 mmHg). Similar results for diastolic pressure suggest that researchers should consider worksite and job characteristics as important predictors of blood pressure differences in working populations.
Schnall PL; Pieper C; Schwartz JE; Karasek RA; Schlussel Y; Devereux RB; Ganau A; Alderman M; Warren K; Pickering TG. The relationship between 'job strain,' workplace diastolic blood pressure, and left ventricular mass index. Results of a case-control study [published erratum appears in JAMA 1992 Mar 4;267(9):1209]. JAMA 1990 Apr 11;263(14):1929-35.
ABSTRACT:
To determine whether "job strain" (defined as high psychological demands and low decision latitude on the job) is associated with increased workplace diastolic blood pressure and the left ventricular mass index, we conducted a case-control study at seven urban work sites of 215 employed men aged 30 to 60 years without evidence of coronary heart disease. After comprehensive blood pressure screening of male employees (N = 2556) at the work site, 87 cases of hypertension and a random sample of 128 controls were studied. In a multiple logistic regression model, job strain was significantly related to hypertension, with an estimated odds ratio of 3.1, after adjusting for age, race, body-mass index, type A behavior, alcohol intake, smoking, work site, 24-hour urine sodium excretion, education, and physical demand level of the job. Controlling for the above variables in subjects aged 30 to 40 years with job strain, we found that the echocardiographically determined left ventricular mass index was, on average, 10.8 g/m2 greater than in subjects without job strain. We conclude that job strain may be a risk factor for both hypertension and structural changes of the heart in working men.
Karasek RA; Theorell T; Schwartz JE; Schnall PL; Pieper CF; Michela JL 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). Am J Public Health 1988 Aug;78(8):910-8.
ABSTRACT:
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.