Job strain as a risk factor for clinical depression: systematic review and meta-analysis with additional individual participant data

BACKGROUND

Adverse psychosocial working environments characterized by job strain (the combination of high demands and low control at work) are associated with an increased risk of depressive symptoms among employees, but evidence on clinically diagnosed depression is scarce. We examined job strain as a risk factor for clinical depression.

METHOD

We identified published cohort studies from a systematic literature search in PubMed and PsycNET and obtained 14 cohort studies with unpublished individual-level data from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium. Summary estimates of the association were obtained using random-effects models. Individual-level data analyses were based on a pre-published study protocol.

RESULTS

We included six published studies with a total of 27 461 individuals and 914 incident cases of clinical depression. From unpublished datasets we included 120 221 individuals and 982 first episodes of hospital-treated clinical depression. Job strain was associated with an increased risk of clinical depression in both published [relative risk (RR) = 1.77, 95% confidence interval (CI) 1.47-2.13] and unpublished datasets (RR = 1.27, 95% CI 1.04-1.55). Further individual participant analyses showed a similar association across sociodemographic subgroups and after excluding individuals with baseline somatic disease. The association was unchanged when excluding individuals with baseline depressive symptoms (RR = 1.25, 95% CI 0.94-1.65), but attenuated on adjustment for a continuous depressive symptoms score (RR = 1.03, 95% CI 0.81-1.32).

CONCLUSIONS

Job strain may precipitate clinical depression among employees. Future intervention studies should test whether job strain is a modifiable risk factor for depression.

Associations between systemic pro-inflammatory markers, cognitive function and cognitive complaints in a population-based sample of working adults

BACKGROUND

The knowledge is limited regarding the relation between systemic inflammatory biomarkers and subjective and objective cognitive functioning in population-based samples of healthy adults across the adult age-span. Thus, the aim of this study was to study a selection of four pro-inflammatory biomarkers (IL-6, MCP-1, TNF-α, CRP) in relation to executive cognitive functioning, episodic memory and subjective cognitive complaints (SCC) in a population-based sample of 215 working adults (age 25-67).

RESULTS

Higher levels of MCP-1 were associated with poorer executive cognitive functioning, even after adjustments for demographical factors, health status/conditions, SCC and depressive symptoms. IL-6 and CRP were associated with poorer executive cognitive functioning, but these associations covaried with age especially and were not present after adjustment for demographical factors. MCP-1 was associated with poorer episodic memory, but this association also covaried with age especially and was not present after adjustment for demographical factors, and CRP was associated with episodic memory only among participants without reported health conditions. Higher MCP-1 levels were also associated with more SCC and this association covaried with depressive symptoms, while higher levels of TNF-α were associated with less SCC.

CONCLUSION

Low grade inflammatory processes in terms of higher systemic levels of pro-inflammatory biomarkers (MCP-1, IL-6 & CRP) were associated with poorer executive functioning in this sample of working adults, and MCP-1 was so after extensive adjustments. Support for associations between these biomarkers and episodic memory and SCC were more limited. Future research should address the causality of associations between low grade inflammatory processes and cognitive functioning.

Predictors of continued playing or singing--from childhood and adolescence to adult years

Aim

Many individuals play an instrument or sing during childhood, but they often stop later in life. This study surveyed adults representative of the Swedish population about musical activities during childhood.

Methods

We asked 3820 adults (65% women) aged from 27 to 54 from the Swedish Twin Registry, who took extra music lessons to those provided at school, to fill in a web‐based questionnaire. Factors analysed were the age they started studying music, the instrument they played, kind of teaching, institution and educational content, number of lessons and perceived characteristics of the lessons, the music environment during their childhood years and their preferred music genre. All variables were dichotomised.

Results

Factors strongly associated with continued playing or singing were male sex, young starting age, cultural family background, self‐selected instrument, attending music classes and more than once a week, church‐related or private education, pop, rock or classical music, playing by ear and improvisation.

Conclusion

Several significant predictors determined whether a child continued to sing or play an instrument as an adult and many could be externally influenced, such as starting at a young age, taking music classes more than once a week, improvisation and the type of music they played.

Job strain and the risk of severe asthma exacerbations: a meta-analysis of individual-participant data from 100 000 European men and women

Background

Many patients and healthcare professionals believe that work‐related psychosocial stress, such as job strain, can make asthma worse, but this is not corroborated by empirical evidence. We investigated the associations between job strain and the incidence of severe asthma exacerbations in working‐age European men and women.

Methods

We analysed individual‐level data, collected between 1985 and 2010, from 102 175 working‐age men and women in 11 prospective European studies. Job strain (a combination of high demands and low control at work) was self‐reported at baseline. Incident severe asthma exacerbations were ascertained from national hospitalization and death registries. Associations between job strain and asthma exacerbations were modelled using Cox regression and the study‐specific findings combined using random‐effects meta‐analyses.

Results

During a median follow‐up of 10 years, 1 109 individuals experienced a severe asthma exacerbation (430 with asthma as the primary diagnostic code). In the age‐ and sex‐adjusted analyses, job strain was associated with an increased risk of severe asthma exacerbations defined using the primary diagnostic code (hazard ratio, HR: 1.27, 95% confidence interval, CI: 1.00, 1.61). This association attenuated towards the null after adjustment for potential confounders (HR: 1.22, 95% CI: 0.96, 1.55). No association was observed in the analyses with asthma defined using any diagnostic code (HR: 1.01, 95% CI: 0.86, 1.19).

Conclusions

Our findings suggest that job strain is probably not an important risk factor for severe asthma exacerbations leading to hospitalization or death.

Job strain in relation to body mass index: pooled analysis of 160 000 adults from 13 cohort studies

BACKGROUND

Evidence of an association between job strain and obesity is inconsistent, mostly limited to small-scale studies, and does not distinguish between categories of underweight or obesity subclasses.

OBJECTIVES

To examine the association between job strain and body mass index (BMI) in a large adult population.

METHODS

We performed a pooled cross-sectional analysis based on individual-level data from 13 European studies resulting in a total of 161 746 participants (49% men, mean age, 43.7 years). Longitudinal analysis with a median follow-up of 4 years was possible for four cohort studies (n = 42 222).

RESULTS

A total of 86 429 participants were of normal weight (BMI 18.5-24.9 kg m(-2) ), 2149 were underweight (BMI < 18.5 kg m(-2) ), 56 572 overweight (BMI 25.0-29.9 kg m(-2) ) and 13 523 class I (BMI 30-34.9 kg m(-2) ) and 3073 classes II/III (BMI ≥ 35 kg m(-2) ) obese. In addition, 27 010 (17%) participants reported job strain. In cross-sectional analyses, we found increased odds of job strain amongst underweight [odds ratio 1.12, 95% confidence interval (CI) 1.00-1.25], obese class I (odds ratio 1.07, 95% CI 1.02-1.12) and obese classes II/III participants (odds ratio 1.14, 95% CI 1.01-1.28) as compared with participants of normal weight. In longitudinal analysis, both weight gain and weight loss were related to the onset of job strain during follow-up.

CONCLUSIONS

In an analysis of European data, we found both weight gain and weight loss to be associated with the onset of job strain, consistent with a 'U'-shaped cross-sectional association between job strain and BMI. These associations were relatively modest; therefore, it is unlikely that intervention to reduce job strain would be effective in combating obesity at a population level.

A prospective cohort study of deficient maternal nurturing attitudes predicting adulthood work stress independent of adulthood hostility and depressive symptoms

Stressful childhood environments arising from deficient nurturing attitudes are hypothesized to contribute to later stress vulnerability. We examined whether deficient nurturing attitudes predict adulthood work stress. Participants were 443 women and 380 men from the prospective Cardiovascular Risk in Young Finns Study. Work stress was assessed as job strain and effort-reward imbalance in 2001 when the participants were from 24 to 39 years old. Deficient maternal nurturance (intolerance and low emotional warmth) was assessed based on mothers' reports when the participants were at the age of 3-18 years and again at the age of 6-21 years. Linear regressions showed that deficient emotional warmth in childhood predicted lower adulthood job control and higher job strain. These associations were not explained by age, gender, socioeconomic circumstances, maternal mental problems or participant hostility, and depressive symptoms. Deficient nurturing attitudes in childhood might affect sensitivity to work stress and selection into stressful work conditions in adulthood. More attention should be paid to pre-employment factors in work stress research.

Covert coping with unfair treatment at work and risk of incident myocardial infarction and cardiac death among men: prospective cohort study

BACKGROUND

Covert coping with unfair treatment at work--occurring when an employee does not show the "aggressor" that he/she feels unfairly treated--has been found to be associated with cardiovascular risk factors. This study examined whether covert coping also predicts incident coronary heart disease.

METHODS

A prospective cohort study (the WOLF Stockholm study) of workplaces in the Stockholm area, Sweden. The participants were 2755 men with no history of myocardial infarction at baseline screening in 1992-1995. The main outcome measure was hospitalisation due to myocardial infarction or death from ischaemic heart disease until 2003 obtained from national registers (mean follow-up 9.8 ± 0.9 years).

RESULTS

Forty-seven participants had myocardial infarction or died from ischaemic heart disease during follow-up. After adjustment for age, socioeconomic factors, risk behaviours, job strain and biological risk factors at baseline, there was a dose-response relationship between covert coping and risk of incident myocardial infarction or cardiac death (p for trend=0.10). Men who frequently used covert coping had a 2.29 (95% CI 1.00 to 5.29) times higher risk than those who did not use coping. Restricting the analysis to direct coping behaviours only strengthened this association (p for trend=0.02).

CONCLUSIONS

In this study, covert coping is strongly related to increased risk of hard-endpoint cardiovascular disease.

Prevalence and characteristics of hearing problems in a working and non-working Swedish population

BACKGROUND

Hearing problems are among the top 10 most common burdens of disease and are projected to be become even more common by the year 2030. The aim of the present study was to give a current assessment of the prevalence of communication difficulties because of hearing loss and tinnitus, in the general Swedish working and non-working populations in relation to sex, age, socioeconomic status (SES) and noise exposure. How prevalence is affected by SES has not been previously established.

METHODS

A total of 18 734 individuals were invited to participate in the study, of which 11 441 (61%) enrolled. Of the participants, 9756 answered the questionnaire for those who work and 1685 answered the version for non-workers.

FINDINGS

The most important findings are that 31% in the working population and 36% in the non-working population report either hearing loss or tinnitus or both. The prevalence of hearing problems increases with age, is higher among men and persons with low self-rated SES, and covaries with exposure to noise at work. Severe hearing problems are already present in men and women under 40 years of age who are exposed to work-related noise.

INTERPRETATION

Prevalence of hearing problems is far more common than previously estimated and is associated with SES and noise exposure history. Hearing problems have a gradual onset that can take years to become recognised. In order to proactively intervene and prevent this deleterious, yet avoidable handicap, statistics need to be regularly updated.

Quality of life and maintenance of improvements after early multimodal rehabilitation: A 5-year follow-up

PURPOSE

There is a paucity of long-term evaluations on rehabilitation of musculoskeletal disorders, e.g., neck, shoulder or back pain. The aim of this study was to assess quality of life and the effect of early multimodal rehabilitation on 91 patients with musculoskeletal pain and disability at a 5-year follow-up.

METHOD

The follow-up assessment, which included questions on pain, function, quality of life, perceived health, sick leave and psychosomatic symptoms, was performed 5 years after the assessment of baseline status.

RESULTS

Improvements in pain, perceived health and psychosomatic symptoms were maintained at the 5-year follow-up. In addition, improvements in function, quality of life, and level of acceptable pain were significant in comparison to baseline. At the time of the baseline assessment all patients were on sick leave (13% were on partial sick leave). At the 5-year follow-up, 58% of the patients were at work part or full time. The results show that those working differed significantly from those not working at the 5-year follow-up on almost all variables, indicating that those working enjoy better health. The most salient prognostic factors for return to work were perceived health and educational level at the time of the baseline evaluation.

CONCLUSIONS

These results show that treatment improved quality of life and the effects were basically maintained at 5 years. Work capacity as reflected in return to work increased greatly (81%) at a 1-year follow-up and was substantial (58%) at the 5-year follow-up. Moreover, perceived health and educational levels were important prognostic factors. Finally, the fact that patients working reported better health underscores the probable importance of return to work. Our results imply that it may be feasible to obtain long-term benefits from such a primary care-based intervention.

Electrocardiographic changes during total energy deprivation (fasting)

The effect of 10 days of total energy deprivation (fasting) on ECG reactions was evaluated in 14 healthy normal-weight males. The heart rate and the ratios between QRS and T wave amplitudes in leads I and II decreased significantly, as did body weight and blood glucose levels. The urinary excretion of adrenaline increased. It is concluded that other hormonal (e.g. thyroidal), neural and metabolic mechanisms are of greater significance for the heart than the sympatho-adreno-medullary activity during fasting. T wave abnormality without an abnormal Q wave and without other clinical symptoms was noted in one subject on the 8th day of starvation and remained abnormal for more than a year.

Relation between ventricular arrhythmias and psychological profile

The association between psychological characteristics and ventricular arrhythmias was investigated in 150 men (50 with manifest IHD, 50 with risk indicators of IHD and 50 healthy men). Arrhythmias were recorded with 24-hour Holter monitoring. Psychological characteristics were assessed by the Emotions Profile Index and the Structured Interview for pattern A behaviour. A depressive emotional state was associated with prognostically severe ventricular arrhythmia in healthy men, but not in men with overt IHD or risk indicators of IHD. When clinical characteristics and age were taken into account, depressiveness was-among healthy men-the second most important factor after high age. The results suggest that-in absence of IHD or other cardiovascular disease-a depressive emotional state may participate in the formation of ventricular arrhythmia.

Relation between arrhythmic sensations, cardiac arrhythmias and psychological profile

The relation between arrhythmic sensations and objective findings of ectopic arrhythmic activity was studied in 150 middle-aged men. Objective arrhythmias were studied by 24-hour Holter monitoring and subjective symptoms assessed by a questionnaire and a dairy protocol during the ECG recording. Psychological characteristics were described by means of a personality inventory, the Emotions Profile Index. No direct relationship was found between subjective symptoms and objective findings of cardiac arrhythmias. Those men, however, who complained of arrhythmic sensations but had no clinically important arrhythmias exhibited a few specific characteristics. They had no signs of organic heart disease and appeared less trustful and more aggressive than those with arrhythmias.

Clinical characteristics of 18-year-old men with elevated blood pressure

Twenty "hypertensive" 18-year-old men (systolic BP greater than or equal to 146 and/or diastolic BP greater than or equal to 90 mmHg) from the screening examinations of a military draught bureau were compared with 17 normotensive (systolic BP 124-131) and 12 hypotensive (systolic BP 100-106) subjects. The hypertensive subjects were on average taller, showed more often ECG evidence of sympathoadrenomedullary overactivity, tended to excrete more adrenaline in the urine during a standardized psychological stress test, had higher serum levels of sodium and potassium and reported more frequently family prevalence of hypertension than the normotensives and hypotensives. Non-participating subjects without verified hypertension had higher mean relative weight than any of the study groups. Only one hypertensive subject showed dilated pulmonary vessels on chest X-ray and borderline evidence of mild left ventricular hypertrophy. None of the hypertensive subjects showed evidence of decreased glomerular filtration rate or endocrine disorder. The subjects in both comparison groups showed frequently ECG evidence of parasympathetic activity. The hypotensive group had a lower average relative body weight than the other groups.

Non-invasive methods for evaluating the importance of heart rate and atrial activity in cardiac pacing. Results of ballistocardiography and digital plethysmography studies in six patients with heart block

Ultralow frequency ballistocardiography (UFB) and digital pulse plethysmography (DPP) were performed in six patients with an external artificial pacemaker system. UFB was used mainly to evaluate the force of contraction of the left ventricle (IJ amplitude) and DPP for evaluating relative changes in the peripheral pulse volume. Four patients were studied at 40, 50, 60, 70, 80, 90 and 100 beats/min. There was a significant decrease (p less than 0.001) in LJ and pulse amplitudes when the heart rate increased from 40 to 100 beats/min. A positive correlation between relative IJ and pulse amplitude was observed in all cases studied. In beat-to-beat analysis it was found that the importance of the PR interval for the IJ and pulse amplitudes varied between patients. It is concluded that both UFB and DPP may be of value in clinical practice for evaluating hemodynamics in patients with slow spontaneous heart rate. The methods may be of help in selecting the most effective type of pacemaker for the individual patient.

Day and night work: changes in cholesterol, uric acid, glucose and potassium in serum and in circadian patterns of urinary catecholamine excretion. A longitudinal cross-over study of railway workers

Two groups of railway workers (n = 16 and n = 17) have been followed on their place of work during a period of shifts between day and night work. Catecholamine excretion in the urine and blood levels of lipids, glucose, uric acid, potassium and calcium were followed during the different phases of shift work. Dramatic fluctuations were noted in the diurnal pattern of catecholamine excretion during and after night work. Significant elevations in the serum levels of cholesterol, glucose, uric acid and potassium were observed during the first week after a night shift, and these changes could not be explained on the basis of shifts in the diurnal pattern or changes in dietary or other habits.

Acute chest pain without obvious organic cause before the age of 40. Respiratory and circulatory response to mental stress

Reactivity to mental stress and relaxation was studied in 63 consecutive patients below the age of 40 attending the emergency care unit because of chest pain without obvious organic cause. The results were compared with a control group (n = 32). Of the patients, 41% reported chest pain or oppression in the chest during mental stress compared to 10% of the control subjects (p less than 0.01). During relaxation the subjects in the female patient group reported significantly less ability to relax and had significantly higher respiration rate as compared to the female control group. There were no significant differences between the groups regarding heart rate, blood pressure or end-tidal PCO2 and there was no evidence of hyperventilation, neither during relaxation nor during mental stress. In combination with our earlier findings of high scores for "type A behaviour", "neuroticism", "vital exhaustion" and "stressful life events" these findings indicate that psychosomatic mechanisms may be of great importance for the development of chest pain in this group of patients.

Managerial leadership and ischaemic heart disease among employees: the Swedish WOLF study

Objective:

To investigate the association between managerial leadership and ischaemic heart disease (IHD) among employees.

Methods:

Data on 3122 Swedish male employees were drawn from a prospective cohort study (WOLF). Baseline screening was carried out in 1992–1995. Managerial leadership behaviours (consideration for individual employees, provision of clarity in goals and role expectations, supplying information and feedback, ability to carry out changes at work successfully, and promotion of employee participation and control) were rated by subordinates. Records of employee hospital admissions with a diagnosis of acute myocardial infarction or unstable angina and deaths from IHD or cardiac arrest to the end of 2003 were used to ascertain IHD. Cox proportional-hazards analyses were used to calculate hazard ratios for incident IHD per 1 standard deviation increase in standardised leadership score.

Results:

74 incident IHD events occurred during the mean follow-up period of 9.7 years. Higher leadership score was associated with lower IHD risk. The inverse association was stronger the longer the participant had worked in the same workplace (age-adjusted hazard ratio 0.76 (95% CI 0.61 to 0.96) for employment for 1 year, 0.77 (0.61 to 0.97) for 2 years, 0.69 (0.54 to 0.88) for 3 years, and 0.61 (0.47 to 0.80) for 4 years); this association was robust to adjustments for education, social class, income, supervisory status, perceived physical load at work, smoking, physical exercise, BMI, blood pressure, lipids, fibrinogen and diabetes. The dose–response association between perceived leadership behaviours and IHD was also evident in subsidiary analyses with only acute myocardial infarction and cardiac death as the outcome.

Conclusion:

If the observed associations were causal then workplace interventions should focus on concrete managerial behaviours in order to prevent IHD in employees.

Psychosocial stress and atherosclerosis: family and work stress accelerate progression of coronary disease in women. The Stockholm Female Coronary Angiography Study

OBJECTIVE

To examine the impact of psychosocial stress, experienced in the family and work life, on the progression of coronary atherosclerosis in women cardiac patients.

DESIGN

Longitudinal follow-up study. The mean luminal diameter change over 3 years was averaged over 10 predefined coronary segments, representing the entire coronary tree. Stress in family life was measured by using the Stockholm Marital Stress Scale and that of work life by the demand-control questionnaire.

SUBJECTS

Amongst patients enrolled in the Stockholm Female Coronary Angiography Study, 80 women were evaluated for stress exposure and coronary atherosclerosis progression using serial quantitative coronary angiography.

RESULTS

Multi-variable-controlled mixed models anova analyses revealed that women with high stress from either family or work had significant disease progression over 3 years, whereas those with low stress had only slight progression. In women who were free of stress from either family or work life, i.e. they were satisfied with both of these life domains, the coronary artery changes had regressed. Their mean coronary luminal diameter increased by 0.22 mm (95% CI: 0.10; 0.35 mm) when compared with women who experienced stress from both sources, whose luminal diameter decreased by 0.20 mm (95% CI: -0.14; -0.25). These associations were independent of baseline luminal diameter and standard cardiovascular risk factors, including age smoking, hypertension and HDL at baseline.

CONCLUSIONS

Stress from family or work life may accelerate coronary disease processes in women, whereas relative protection may be obtained from a satisfactory job and a happy marriage.

Are intrinsic motivational factors of work associated with functional incapacity similarly regardless of the country?

BACKGROUND

Many psychosocial models of wellbeing at work emphasise the role of intrinsic motivational factors such as job autonomy, job complexity, and innovativeness. However, little is known about whether the employees of multinational enterprises differ from country to country with regard to intrinsic motivational factors, and whether these factors are associated with wellbeing similarly in the different countries. The purpose of this study was to examine the level of intrinsic motivational factors and their impact on functional incapacity in different countries in a multinational corporation.

METHODS

In 2000, data were collected from a globally operating corporation with a questionnaire survey. The participants were 13 795 employees (response rate 59%; 56% under age 45; 80% men; 61% blue collar employees), who worked in similar industrial occupations in five countries (Canada, China, Finland, France, and Sweden).

RESULTS

The Chinese employees reported higher autonomy and lower complexity at work than the employees from the other countries. After adjustment for age, sex, socioeconomic status, and physical work environment, job autonomy, and job complexity at work were associated with functional incapacity in most countries, whereas in China the impact was significantly stronger. In Finland and in China employees with low innovativeness at work were more prone to functional incapacity than corresponding employees in other countries.

CONCLUSIONS

The level of intrinsic motivational factors varied between the Chinese employees and those in other countries. In line with theoretical notions, the relation between intrinsic motivational factors of work and functional incapacity followed a similar pattern in the different countries. However, these country specific results show that a culture specific approach to employee wellbeing should also be applied.

Acoustics and psychosocial environment in intensive coronary care

BACKGROUND

Stress, strain, and fatigue at the workplace have previously not been studied in relation to acoustic conditions.

AIMS

To examine the influence of different acoustic conditions on the work environment and the staff in a coronary critical care unit (CCU).

METHOD

Psychosocial work environment data from start and end of each individual shift were obtained from three shifts (morning, afternoon, and night) for a one-week baseline period and for two four-week periods during which either sound reflecting or sound absorbing tiles were installed.

RESULTS

Reverberation times and speech intelligibility improved during the study period when the ceiling tiles were changed from sound reflecting tiles to sound absorbing ones of identical appearance. Improved acoustics positively affected the work environment; the afternoon shift staff experienced significantly lower work demands and reported less pressure and strain.

CONCLUSIONS

Important gains in the psychosocial work environment of healthcare can be achieved by improving room acoustics. The study points to the importance of further research on possible effects of acoustics in healthcare on staff turnover, quality of patient care, and medical errors.

Mental fatigue, work and sleep

OBJECTIVE

The study examined the multivariate relationship between mental fatigue and different work-related (work load, work hours) and background/life style factors, as well as disturbed sleep.

METHODS

A total of 5720 healthy employed men and women living in the greater Stockholm area participated in a questionnaire study on cardiovascular risk factors. The data were analysed using a multiple logistic regression analysis with self-rated fatigue as the dependent variable.

RESULTS

Fatigue was predicted by disturbed sleep (4.31; 3.50-5.45, high immersion in work (4.17; 2.93-5.94), high work demands (2.39; 1.54-3.69), social support, being a female, being a supervisor and high age. Shift work, work hours (including overtime) and influence at work did not become significant predictors. With control for work demands a high number of work hours was associated with lower fatigue.

CONCLUSION

Disturbed sleep is an important predictor of fatigue, apparently stronger than previously well-established predictors such as work load, female gender, lack of exercise, etc.

Low job control and myocardial infarction risk in the occupational categories of Kaunas men, Lithuania

STUDY OBJECTIVE

To determine the association between adverse psychosocial characteristics at work and risk of first myocardial infarction in the occupational categories of Kaunas men, Lithuania.

DESIGN

The analysis was based upon a case-control study among full time working men in the general population of Kaunas.

OUTCOME MEASURE

First non-fatal myocardial infarction diagnosed in 2001-2002. The Swedish version of the demand-control questionnaire was used to examine the effect of job control and demands.

SETTING

Kaunas, the second largest city in Lithuania, a former socialist country in a transition market economy.

PARTICIPANTS

Cases were 203 men 25-64 years of age with a first non-fatal myocardial infarction and controls were 287 men group randomly selected from the study base.

MAIN RESULTS

Low job control had a significant effect on myocardial infarction risk in the general 25-64 year old Kaunas male population (OR = 2.68; 95% CI 1.68 to 4.28) after adjustment for age and socioeconomic status. Low job control was a risk factor in the occupational categories of the increased myocardial infarction risk (1st occupational category--legislators, senior officials and managers and the 8th--plant and machine operators and assemblers; OR = 2.78; 95% CI 1.31 to 5.93 and 2.72; 95% CI 1.56 to 4.89, respectively, after adjustment for age and socioeconomic status). Though the adjusted odds ratio estimates were significantly high for the rest of the occupational categories (2nd--professionals, 3rd--technicians and associate professionals, and 7th--craft and related trades workers).

CONCLUSIONS

The association between low job control and first myocardial infarction risk was significant for all occupational categories of Kaunas men.

Downsizing of staff is associated with lowered medically certified sick leave in female employees

AIM

To determine whether changes in number of staff in work sites are associated with medically certified sick leave among employees with an increased risk of developing cardiovascular disease.

METHODS

The 5720 employees (aged 18-65) were from the WOLF study of cardiovascular risk factors in working men and women in greater Stockholm during the years 1992-95. From the medical examination a cardiovascular score was calculated for each participant. The WOLF study base was linked to a Statistics Sweden registry of economic and administrative activities. Sick leave spells lasting for at least 15 days during the calendar year following downsizing/expansion were identified for each subject.

RESULTS

In multiple logistic regression an increased likelihood of having no medically certified sick leave (15 days or more) was found in women during the year following both downsizing and expansion. These analyses were adjusted for age and cardiovascular score. A high cardiovascular risk score reduced the likelihood of having no medically certified sick leave. The inclusion of psychosocial work environment variables did not change the results markedly. Separate analyses of women with and without high cardiovascular score showed that downsizing had a more pronounced effect on reduced long term sick leave among those with high than among those without low cardiovascular score. There were no consistent findings in men.

CONCLUSIONS

There is evidence of a reduction of long term sick leave in women after downsizing and this is particularly evident among those with high cardiovascular score.

Work organisation and unintentional sleep: results from the WOLF study

BACKGROUND

Falling asleep at work is receiving increasing attention as a cause of work accidents.

AIMS

To investigate which variables (related to work, lifestyle, or background) are related to the tendency to fall asleep unintentionally, either during work hours, or during leisure time.

METHODS

5589 individuals (76% response rate) responded to a questionnaire. A multiple logistic regression analysis of the cross sectional data was used to estimate the risk of falling asleep.

RESULTS

The prevalence for falling asleep unintentionally at least once a month was 7.0% during work hours and 23.1% during leisure time. The risk of unintentional sleep at work was related to disturbed sleep, having shift work, and higher socioeconomic group. Being older, being a woman, and being a smoker were associated with a reduced risk of unintentionally falling asleep at work. Work demands, decision latitude at work, physical load, sedentary work, solitary work, extra work, and overtime work were not related to falling asleep at work. Removing "disturbed sleep" as a predictor did not change the odds ratios of the other predictors in any significant way. With respect to falling asleep during leisure time, disturbed sleep, snoring, high work demands, being a smoker, not exercising, and higher age (>45 years) became risk indicators.

CONCLUSION

The risk of involuntary sleep at work is increased in connection with disturbed sleep but also with night work, socioeconomic group, low age, being a male, and being a non-smoker.

Sleep disturbances, work stress and work hours: a cross-sectional study

OBJECTIVE

The study examined the multivariate relationship between disturbed sleep and different work-related and background/life style factors.

METHODS

5720 healthy employed men and women living in the greater Stockholm area participated. A factor analysis of eight items provided one main factor: "disturbed sleep." The data were analyzed using a multiple logistic regression analysis against the index disturbed sleep as well as the separate items "not well rested" and "difficulties awakening."

RESULTS

The results showed that high work demands [odds ratio (OR) = 2.15] and physical effort at work (OR = 1.94) are risk indicators for disturbed sleep, while high social support is associated with reduced risk (OR = 0.44). In addition, higher age (45+), female gender, a high body mass index (BMI) and lack of exercise are background/life style risk indicators. Introducing into the model an item representing inability to stop thinking about work during free time yielded the highest OR (3.20) and forced work demands out of the regression. With regard to not feeling well rested, the same significant predictors, except physical effort, were obtained, as well as for having night work and being married. In addition, the age effect was reversed--high age predicted reduced risk of not feeling well rested. Difficulties awakening was predicted by high work demands, low social support, being male, low age and smoking. It is notable that, whereas subjective sleep quality decreased with age, the difficulties awakening and feelings of not being well rested after sleep increased with age.

CONCLUSION

It was concluded that stress and the social situation at work are strongly linked to disturbed sleep and impaired awakening, that gender and, even more so, age may modify this and that the inability to stop worrying about work during free time may be an important link in the relation between stress and sleep.

Psychosocial work environment and myocardial infarction: improving risk estimation by combining two complementary job stress models in the SHEEP Study

OBJECTIVES

Associations between two alternative formulations of job stress derived from the effort-reward imbalance and the job strain model and first non-fatal acute myocardial infarction were studied. Whereas the job strain model concentrates on situational (extrinsic) characteristics the effort-reward imbalance model analyses distinct person (intrinsic) characteristics in addition to situational ones. In view of these conceptual differences the hypothesis was tested that combining information from the two models improves the risk estimation of acute myocardial infarction.

METHODS

951 male and female myocardial infarction cases and 1147 referents aged 45-64 years of The Stockholm Heart Epidemiology (SHEEP) case-control study underwent a clinical examination. Information on job stress and health adverse behaviours was derived from standardised questionnaires.

RESULTS

Multivariate analysis showed moderately increased odds ratios for either model. Yet, with respect to the effort-reward imbalance model gender specific effects were found: in men the extrinsic component contributed to risk estimation, whereas this was the case with the intrinsic component in women. Controlling each job stress model for the other in order to test the independent effect of either approach did not show systematically increased odds ratios. An improved estimation of acute myocardial infarction risk resulted from combining information from the two models by defining groups characterised by simultaneous exposure to effort-reward imbalance and job strain (men: odds ratio 2.02 (95% confidence intervals (CI) 1.34 to 3.07); women odds ratio 2.19 (95% CI 1.11 to 4.28)).

CONCLUSIONS

Findings show an improved risk estimation of acute myocardial infarction by combining information from the two job stress models under study. Moreover, gender specific effects of the two components of the effort-reward imbalance model were observed.

Self-reported life event patterns and their relation to health among recently resettled Iraqi and Kurdish refugees in Sweden

This paper presents the findings of a longitudinal study of life events in refugees belonging to different language groups from Iraq. Eighty-six individuals were included in the study. Data regarding life events and self-reported health measurements were collected after baseline assessment with 3-monthly intervals on three occasions. Posttraumatic stress disorder was diagnosed by means of a structured interview at baseline. The results indicate that the subjects were influenced to a great extent by political events and the situation of significant others in the home country. Further, the number of negative life events in the host country showed a significant association with self-rated deteriorated health. In subjects with posttraumatic stress disorder, the effects of certain life events were more pronounced.

Employee effects of an educational program for managers at an insurance company

BACKGROUND

Possible health effects for employees of efforts to improve the psychosocial competence of managers have not been studied scientifically in the past.

OBJECTIVE

To explore how efforts to improve management will change the work environment and health of the employees.

METHODS

Managers of the experimental department in a large insurance corporation underwent 2-hour biweekly training sessions for 1 year-altogether, 60 hours. A control group of employees in other departments in the corporation not affected by the modification was followed with the same assessments. Morning blood samples for the assessment of serum cortisol were collected both at baseline and after 1 year in 155 participants in the experimental group and in 147 subjects in the control group. Liver enzymes and lipids were also assessed. In the questionnaire part of the 1-year follow-up study, there were 119 participants in the experimental group and 132 in the control group.

RESULTS

When repeated-measures ANOVA was used, a significant interaction effect was found for the level of serum cortisol; serum cortisol levels were decreased in the intervention group and were unchanged in the control group (ANOVA two-way interaction, p =.02; after exclusion of the managers, p =.005). A significant interaction effect was also observed for decision authority, with increased decision authority in the intervention group and, conversely, a decreased level in the control group (p =.001; after exclusion of managers, p =.02).

CONCLUSIONS

The study indicates that a moderately intensive psychosocial manager program lasting for 1 year can be beneficial for the employees with regard to both lowered serum cortisol and improved authority over decisions.

The influence on seeking care because of neck and shoulder disorders from work-related exposures

The aim of this study was to assess the influence of work-related physical and psychosocial factors on seeking care for neck or shoulder disorders among men and women in a general working population. The study population comprised gainfully employed (>17 hours per week) men and women in the municipality of Norrtälje, altogether 392 cases and 1,511 controls. Cases were defined as persons seeking care because of neck or shoulder disorders by any caregiver in the region. The study began in 1994 and continued to 1997. We assessed physical and psychosocial exposures by questionnaires and interviews. The pattern of seeking care for neck or shoulder disorders differed between men and women. Among men, work with vibrating tools [relative risk (RR) = 1.6], not having a fixed salary (RR = 1.9), and low demands in relation to competence (RR = 1.5) were the strongest risk indicators obtained in analyses stratified for age and previous symptoms. Among women, repetitive hand or finger movements (RR = 1.6), constrained sitting (RR = 1.6), not having a fixed salary (RR = 2.0), and solitary work (RR = 1.8) were the strongest risk indicators. A large proportion of the general population was exposed to several of these moderately harmful conditions, and their concomitant effect may explain the high incidence of neck and shoulder disorders in the general working population.

Stress markers in relation to job strain in human service organizations

BACKGROUND

Workers in human service organizations are often confronted with conflicting demands in providing care or education. The aim of this cross-sectional study was to relate levels of endocrine stress markers to perceived job strain in two human service organizations.

METHODS

Employees in two local units of the social insurance organization and two local units of the individual and family care sections of the social welfare in Sweden were selected and 103 employees participated (56% participation rate). The perceived job strain was assessed with a standardized questionnaire containing questions of the demand-control model. Questions specially designed to measure emotional demands were also included. The stress markers cortisol, prolactin, thyroid-stimulating hormone, testosterone and IgA and IgG were analysed in blood samples.

RESULTS

The main finding was an association between high emotional strain and increased levels of prolactin. The levels of cortisol, but none of the other four stress markers, increased slightly with emotional strain.

CONCLUSIONS

Emotional strain experienced in human service work may cause psychological stress. The increase in prolactin was modest but consistent with findings in other published studies on stress-related endocrine alterations.

Dissonant imperatives in nursing: a conceptualization of stress in intensive care in Sweden

The aim of this study was to explore nurses' experiences of stress within the context of intensive care. The theoretical perspective for the study builds on a cognitive-phenomenological-transactional theory of stress and coping and the theory of cognitive dissonance. Respondents were 36 registered nurses recruited from 10 intensive care units (general, neonatal and thoracic units). Their experience as nurses ranged from one to 32 years. These intensive care units had similar structural characteristics, namely a high working pace, advanced technology, constrained finances, frequent reorganizations, a shortage of registered nurses and all were filled to overcapacity. Data were collected in open-ended interviews that were audio-taped and transcribed. A content analysis identified four contradictory themes: (1) controlled by the work situation--needing to be in control; (2) constrained by prioritization--wanting to do more; (3) lacking the authority to act--knowing that something should be done; and (4) professional distance--interpersonal involvement. These four themes were synthesized at a higher level of abstraction into a main theme: stress induced by dissonant imperatives, which conceptualizes nursing stress in the intensive care unit. In conclusion, dissonant imperatives might lead to stress in intensive care nursing.