Long working hours and change in body weight: analysis of individual-participant data from 19 cohort studies.

OBJECTIVE: To examine the relation between long working hours and change in body mass index (BMI). METHODS: We performed random effects meta-analyses using individual-participant data from 19 cohort studies from Europe, US and Australia (n = 122,078), with a mean of 4.4-year follow-up. Working hours were measured at baseline and categorised as part time (<35 h/week), standard weekly hours (35-40 h, reference), 41-48 h, 49-54 h and ≥55 h/week (long working hours). There were four outcomes at follow-up: (1) overweight/obesity (BMI ≥ 25 kg/m2) or (2) overweight (BMI 25-29.9 kg/m2) among participants without overweight/obesity at baseline; (3) obesity (BMI ≥ 30 kg/m2) among participants with overweight at baseline, and (4) weight loss among participants with obesity at baseline. RESULTS: Of the 61,143 participants without overweight/obesity at baseline, 20.2% had overweight/obesity at follow-up. Compared with standard weekly working hours, the age-, sex- and socioeconomic status-adjusted relative risk (RR) of overweight/obesity was 0.95 (95% CI 0.90-1.00) for part-time work, 1.07 (1.02-1.12) for 41-48 weekly working hours, 1.09 (1.03-1.16) for 49-54 h and 1.17 (1.08-1.27) for long working hours (P for trend <0.0001). The findings were similar after multivariable adjustment and in subgroup analyses. Long working hours were associated with an excess risk of shift from normal weight to overweight rather than from overweight to obesity. Long working hours were not associated with weight loss among participants with obesity. CONCLUSIONS: This analysis of large individual-participant data suggests a small excess risk of overweight among the healthy-weight people who work long hours.

Long working hours and risk of coronary heart disease and stroke: a systematic review and meta-analysis of published and unpublished data for 603,838 individuals.

BACKGROUND: Long working hours might increase the risk of cardiovascular disease, but prospective evidence is scarce, imprecise, and mostly limited to coronary heart disease. We aimed to assess long working hours as a risk factor for incident coronary heart disease and stroke. METHODS: We identified published studies through a systematic review of PubMed and Embase from inception to Aug 20, 2014. We obtained unpublished data for 20 cohort studies from the Individual-Participant-Data Meta-analysis in Working Populations (IPD-Work) Consortium and open-access data archives. We used cumulative random-effects meta-analysis to combine effect estimates from published and unpublished data. FINDINGS: We included 25 studies from 24 cohorts in Europe, the USA, and Australia. The meta-analysis of coronary heart disease comprised data for 603,838 men and women who were free from coronary heart disease at baseline; the meta-analysis of stroke comprised data for 528,908 men and women who were free from stroke at baseline. Follow-up for coronary heart disease was 5·1 million person-years (mean 8·5 years), in which 4768 events were recorded, and for stroke was 3·8 million person-years (mean 7·2 years), in which 1722 events were recorded. In cumulative meta-analysis adjusted for age, sex, and socioeconomic status, compared with standard hours (35-40 h per week), working long hours (≥55 h per week) was associated with an increase in risk of incident coronary heart disease (relative risk [RR] 1·13, 95% CI 1·02-1·26; p=0·02) and incident stroke (1·33, 1·11-1·61; p=0·002). The excess risk of stroke remained unchanged in analyses that addressed reverse causation, multivariable adjustments for other risk factors, and different methods of stroke ascertainment (range of RR estimates 1·30-1·42). We recorded a dose-response association for stroke, with RR estimates of 1·10 (95% CI 0·94-1·28; p=0·24) for 41-48 working hours, 1·27 (1·03-1·56; p=0·03) for 49-54 working hours, and 1·33 (1·11-1·61; p=0·002) for 55 working hours or more per week compared with standard working hours (ptrend<0·0001). INTERPRETATION: Employees who work long hours have a higher risk of stroke than those working standard hours; the association with coronary heart disease is weaker. These findings suggest that more attention should be paid to the management of vascular risk factors in individuals who work long hours. FUNDING: Medical Research Council, Economic and Social Research Council, European Union New and Emerging Risks in Occupational Safety and Health research programme, Finnish Work Environment Fund, Swedish Research Council for Working Life and Social Research, German Social Accident Insurance, Danish National Research Centre for the Working Environment, Academy of Finland, Ministry of Social Affairs and Employment (Netherlands), US National Institutes of Health, British Heart Foundation.

The indirect association of job strain with long-term sickness absence through bullying: a mediation analysis using structural equation modeling.

BACKGROUND: In this longitudinal study the complex interplay between both job strain and bullying in relation to sickness absence was investigated. Following the "work environment hypothesis", which establishes several work characteristics as antecedents of bullying, we assumed that job strain, conceptualized by the Job-Demand-Control model, has an indirect relation with long-term sickness absence through bullying. METHODS: The sample consisted of 2983 Belgian workers, aged 30 to 55 years, who participated in the Belstress III study. They completed a survey, including the Job Content Questionnaire and a bullying inventory, at baseline. Their sickness absence figures were registered during 1 year follow-up. Long-term sickness absence was defined as at least 15 consecutive days. A mediation analysis, using structural equation modeling, was performed to examine the indirect association of job strain through bullying with long-term sickness absence. The full structural model was adjusted for several possible confounders: age, gender, occupational group, educational level, company, smoking habits, alcohol use, body mass index, self-rated health, baseline long-term sickness absence and neuroticism. RESULTS: The results support the hypothesis: a significant indirect association of job strain with long-term sickness absence through bullying was observed, suggesting that bullying is an intermediate variable between job strain and long-term sickness absence. No evidence for the reversed pathway of an indirect association of bullying through job strain was found. CONCLUSIONS: Bullying was observed as a mediating variable in the relation between job strain and sickness absence. The results suggest that exposure to job strain may create circumstances in which a worker risks to become a target of bullying. Our findings are generally in line with the work environment hypothesis, which emphasizes the importance of organizational work factors in the origin of bullying. This study highlights that remodeling jobs to reduce job strain may be important in the prevention of bullying and subsequent sickness absence.

Do psychosocial job resources buffer the relation between physical work demands and coronary heart disease? A prospective study among men.

PURPOSE: Increasing evidence shows the detrimental impact of high physical work demands for cardiovascular health and mortality. The aim of this study was to investigate the buffering effects of social support at work and job control in the relation between physical work demands and incidence of coronary events. METHODS: The study included 14,337 middle-aged men free from coronary heart disease (CHD) at baseline. The sample consisted of a mixed occupational group recruited within 18 organizations from the manufacturing, service, and public sector. Data were collected through standardized questionnaires and clinical examinations. The incidence of clinical coronary events was monitored during a mean follow-up time of 3.15 years. Multilevel Cox proportional hazard regression modeling was used, adjusting for socio-demographic and classical coronary risk factors. RESULTS: Social support at work buffered the impact of physical work demands on CHD risk: Only among workers with low social support at work did physical work demands significantly increase the risk for CHD incidence (fully adjusted HR 2.50: 95 % CI 1.13-5.50), while this harmful effect completely disappeared in case of high level of workplace social support (fully adjusted HR 0.40; 95 % CI 0.09-1.70). No interaction or buffering effect with job control was observed. CONCLUSIONS: The results of our study suggest that supportive relationships at work may be a useful resource for reducing the cardiovascular risk associated with physical work demands in men. Future studies are needed to confirm this moderating role of workplace social support and to unravel the underlying mechanisms.

The combined relationship of occupational and leisure-time physical activity with all-cause mortality among men, accounting for physical fitness.

The aim of this study was to assess the combined relationship of occupational physical activity and leisure-time physical activity with all-cause mortality among men, while accounting for physical fitness. The prospective Belgian Physical Fitness Study included 1,456 male workers aged 40-55 years who were free of coronary heart disease at baseline. Baseline data were collected through questionnaires and clinical examinations from 1976 to 1978. To estimate physical fitness, a submaximal graded exercise test was performed on a bicycle ergometer. Total mortality was registered during a mean follow-up period of 16.9 years. Main results were obtained through Cox proportional hazards regression analysis. A total of 145 deaths were registered during follow-up. After adjustment for confounders, a significantly increased mortality rate was observed in workers who had low levels of both physical activity types (hazard ratio = 2.07, 95% confidence interval: 1.03, 4.19) but also in workers combining high occupational physical activity and low leisure-time physical activity (hazard ratio = 2.04, 95% confidence interval: 1.07, 3.91); the latter finding was particularly pronounced among workers with a low physical fitness level. The present results confirm the existence of a complex interplay among different physical activity settings and fitness levels in predicting mortality.

The relation between psychosocial risk factors and cause-specific long-term sickness absence.

BACKGROUND: The aim was to study the impact of psychosocial risk factors on long-term sickness absence due to mental health problems (LSA-MH) or musculoskeletal disorders (LSA-MSD) in 2983 Belgian middle-aged workers. METHODS: Data were collected from 1372 male and 1611 female workers in the Belstress III study. Considered psychosocial risk factors were job demands, job control, social support, job strain, efforts, rewards, effort-reward imbalance and bullying. Prospective registered sickness absence data were collected during 12 months follow-up; the causes for long-term sickness absence episodes of at least 15 consecutive days were obtained by contacting the general practitioner of the worker. Multiple logistic regression models were used to investigate the relationship between the psychosocial risk factors and LSA-MH and LSA-MSD. RESULTS: Higher levels of rewards at baseline were independently and significantly associated with a lower risk for LSA-MH. Higher levels of control were associated with a lower risk for LSA-MSD during follow-up. Higher job demands and efforts were significantly related to a lower risk for LSA-MSD. Finally, bullying was significantly and independently related to both LSA-MH and LSA-MSD during the follow-up period. CONCLUSIONS: These results suggest that psychosocial risk factors are related to LSA-MH and LSA-MSD, of which especially bullying seems to be a potent stressor.

[Exploratory analysis of work engagement: use of the Utrecht scale in Benin]. / Analyse exploratoire de l'engagement au travail: utilisation de l'echelle d'Utrecht au Bénin.

INTRODUCTION: Work engagement, an emerging concept in the field of positive psychology in the workplace is not well known in developing countries. Defined as a positive and and fulfilling mindset related to work, it recalls a positive attitude incentive of performance and need to be investigated. In the context of the socioeconomic crisis of health workers, and with the chronic issue of poor quality of data, this study was designed to identify the factors associated with work engagement among health workers. in charge of data collection in the Benin Routine Health Information System. METHODS: This study was a cross-sectional and analytical study targeting health workers in charge of data collection in public and private health centres. The dependent variable was work engagement and independent variables were sociodemographic and professional features, personal and professional resources and perception of technical factors. Logistic regression was used. The adequacy of the model was tested with the Hosmer-Lemeshow goodness of fit test. RESULTS: The results indicate that the level of work engagement is similar with that observed in previous studies. Predictors identified in logistic regression are perception of technical factors, location of the job, and personal resources, such as level of effort and overcommitment. DISCUSSION: This study identified factors associated with work engagement in a developing country, and adds to the knowledge concerning this new concept in Benin. The findings can contribute to research for improvement of human resources management in the health sector to achieve real performance and development.

Job strain as a risk factor for coronary heart disease: a collaborative meta-analysis of individual participant data.

BACKGROUND: Published work assessing psychosocial stress (job strain) as a risk factor for coronary heart disease is inconsistent and subject to publication bias and reverse causation bias. We analysed the relation between job strain and coronary heart disease with a meta-analysis of published and unpublished studies. METHODS: We used individual records from 13 European cohort studies (1985-2006) of men and women without coronary heart disease who were employed at time of baseline assessment. We measured job strain with questions from validated job-content and demand-control questionnaires. We extracted data in two stages such that acquisition and harmonisation of job strain measure and covariables occurred before linkage to records for coronary heart disease. We defined incident coronary heart disease as the first non-fatal myocardial infarction or coronary death. FINDINGS: 30,214 (15%) of 197,473 participants reported job strain. In 1·49 million person-years at risk (mean follow-up 7·5 years [SD 1·7]), we recorded 2358 events of incident coronary heart disease. After adjustment for sex and age, the hazard ratio for job strain versus no job strain was 1·23 (95% CI 1·10-1·37). This effect estimate was higher in published (1·43, 1·15-1·77) than unpublished (1·16, 1·02-1·32) studies. Hazard ratios were likewise raised in analyses addressing reverse causality by exclusion of events of coronary heart disease that occurred in the first 3 years (1·31, 1·15-1·48) and 5 years (1·30, 1·13-1·50) of follow-up. We noted an association between job strain and coronary heart disease for sex, age groups, socioeconomic strata, and region, and after adjustments for socioeconomic status, and lifestyle and conventional risk factors. The population attributable risk for job strain was 3·4%. INTERPRETATION: Our findings suggest that prevention of workplace stress might decrease disease incidence; however, this strategy would have a much smaller effect than would tackling of standard risk factors, such as smoking. FUNDING: Finnish Work Environment Fund, the Academy of Finland, the Swedish Research Council for Working Life and Social Research, the German Social Accident Insurance, the Danish National Research Centre for the Working Environment, the BUPA Foundation, the Ministry of Social Affairs and Employment, the Medical Research Council, the Wellcome Trust, and the US National Institutes of Health.

Job strain and health-related lifestyle: findings from an individual-participant meta-analysis of 118,000 working adults.

OBJECTIVES: We examined the associations of job strain, an indicator of work-related stress, with overall unhealthy and healthy lifestyles. METHODS: We conducted a meta-analysis of individual-level data from 11 European studies (cross-sectional data: n = 118,701; longitudinal data: n = 43,971). We analyzed job strain as a set of binary (job strain vs no job strain) and categorical (high job strain, active job, passive job, and low job strain) variables. Factors used to define healthy and unhealthy lifestyles were body mass index, smoking, alcohol intake, and leisure-time physical activity. RESULTS: Individuals with job strain were more likely than those with no job strain to have 4 unhealthy lifestyle factors (odds ratio [OR] = 1.25; 95% confidence interval [CI] = 1.12, 1.39) and less likely to have 4 healthy lifestyle factors (OR = 0.89; 95% CI = 0.80, 0.99). The odds of adopting a healthy lifestyle during study follow-up were lower among individuals with high job strain than among those with low job strain (OR = 0.88; 95% CI = 0.81, 0.96). CONCLUSIONS: Work-related stress is associated with unhealthy lifestyles and the absence of stress is associated with healthy lifestyles, but longitudinal analyses suggest no straightforward cause-effect relationship between work-related stress and lifestyle.

Associations of job strain and lifestyle risk factors with risk of coronary artery disease: a meta-analysis of individual participant data.

BACKGROUND: It is unclear whether a healthy lifestyle mitigates the adverse effects of job strain on coronary artery disease. We examined the associations of job strain and lifestyle risk factors with the risk of coronary artery disease. METHODS: We pooled individual-level data from 7 cohort studies comprising 102 128 men and women who were free of existing coronary artery disease at baseline (1985-2000). Questionnaires were used to measure job strain (yes v. no) and 4 lifestyle risk factors: current smoking, physical inactivity, heavy drinking and obesity. We grouped participants into 3 lifestyle categories: healthy (no lifestyle risk factors), moderately unhealthy (1 risk factor) and unhealthy (2-4 risk factors). The primary outcome was incident coronary artery disease (defined as first nonfatal myocardial infarction or cardiac-related death). RESULTS: There were 1086 incident events in 743,948 person-years at risk during a mean follow-up of 7.3 years. The risk of coronary artery disease among people who had an unhealthy lifestyle compared with those who had a healthy lifestyle (hazard ratio [HR] 2.55, 95% confidence interval [CI] 2.18-2.98; population attributable risk 26.4%) was higher than the risk among participants who had job strain compared with those who had no job strain (HR 1.25, 95% CI 1.06-1.47; population attributable risk 3.8%). The 10-year incidence of coronary artery disease among participants with job strain and a healthy lifestyle (14.7 per 1000) was 53% lower than the incidence among those with job strain and an unhealthy lifestyle (31.2 per 1000). INTERPRETATION: The risk of coronary artery disease was highest among participants who reported job strain and an unhealthy lifestyle; those with job strain and a healthy lifestyle had half the rate of disease. A healthy lifestyle may substantially reduce disease risk among people with job strain.

The association between leisure time physical activity and coronary heart disease among men with different physical work demands: a prospective cohort study.

The interplay of occupational and leisure time physical activity (LTPA) in affecting cardiovascular health is subject to debate. This study aimed to examine the independent and interacting associations of leisure time and occupational physical activity (OPA) with the incidence of coronary events within the BELSTRESS cohort. The study included 14,337 middle-aged men free from coronary heart disease at baseline. Standardized questionnaires and clinical examinations were used to assess socio-demographic factors, level of physical activity, job strain and classical coronary risk factors. The incidence of clinical coronary events was monitored during a mean follow-up time of 3.15 years. Results demonstrated overall a beneficial relation of LTPA and an adverse relation of physical work demands with cardiovascular health. However, an interaction effect between both physical activity types was observed, showing that men with high physical job demands who also engaged in physical activity during leisure time had an almost four times increased incidence of coronary events after adjusting for socio-demographic and classical coronary risk factors (HR 3.82; 95% CI 1.41-10.36). Stratified analyses revealed that moderate to high physical activity during leisure time was associated with a 60% reduced incidence rate of coronary events in men with low OPA (age adjusted HR 0.40; 95% CI 0.21-0.76), while this protective association was not observed in workers being exposed to high physical work demands (age adjusted HR 1.67; 95% CI 0.63-4.48). These findings suggest that recommendations regarding LTPA should be tailored according to the level of occupational physical activity.

Gender difference in sickness absence from work: a multiple mediation analysis of psychosocial factors.

BACKGROUND: Previous research has shown that job characteristics, private life and psychosocial factors partially account for gender difference in work absences because of sickness. Most studies have analysed these factors separately. The aim of the present study was to evaluate whether these explanatory factors act as mediators when they are considered simultaneously. METHODS: The evaluated data set comprises the merger of two Belgian longitudinal studies, BELSTRESS III and SOMSTRESS. It includes 3821 workers (1541 men) aged 21-66 years, employed in eight organizations. A multiple mediation analysis was performed to explain the higher prevalence among women. Estimated factors were occupational grade, total number of paid working hours per week, job strain, overcommitment, home-work interference and social support at and outside work. Prospective data concerning duration and frequency of medically justified sickness absence (registered by the organizations) were used as outcomes. RESULTS: Overall, the mediating factors partially account for gender difference in sickness absence. The strongest mediator for both outcomes is job strain. In addition, difference in absence duration is mediated by social support at work, whereas difference in frequency is mediated by professional grade and home-work interference. CONCLUSIONS: Our results call attention to the necessity to elaborate actual preventive actions aiming at favouring a better positioning of women on the labour market in term of hierarchical level as well as in terms of quality of work for reducing sickness absence in this group.

Job strain as a risk factor for leisure-time physical inactivity: an individual-participant meta-analysis of up to 170,000 men and women: the IPD-Work Consortium.

Unfavorable work characteristics, such as low job control and too high or too low job demands, have been suggested to increase the likelihood of physical inactivity during leisure time, but this has not been verified in large-scale studies. The authors combined individual-level data from 14 European cohort studies (baseline years from 1985-1988 to 2006-2008) to examine the association between unfavorable work characteristics and leisure-time physical inactivity in a total of 170,162 employees (50% women; mean age, 43.5 years). Of these employees, 56,735 were reexamined after 2-9 years. In cross-sectional analyses, the odds for physical inactivity were 26% higher (odds ratio = 1.26, 95% confidence interval: 1.15, 1.38) for employees with high-strain jobs (low control/high demands) and 21% higher (odds ratio = 1.21, 95% confidence interval: 1.11, 1.31) for those with passive jobs (low control/low demands) compared with employees in low-strain jobs (high control/low demands). In prospective analyses restricted to physically active participants, the odds of becoming physically inactive during follow-up were 21% and 20% higher for those with high-strain (odds ratio = 1.21, 95% confidence interval: 1.11, 1.32) and passive (odds ratio = 1.20, 95% confidence interval: 1.11, 1.30) jobs at baseline. These data suggest that unfavorable work characteristics may have a spillover effect on leisure-time physical activity.

Occupational and leisure time physical activity in contrasting relation to ambulatory blood pressure.

BACKGROUND: While moderate and vigorous leisure time physical activities are well documented to decrease the risk for cardiovascular disease, several studies have demonstrated an increased risk for cardiovascular disease in workers with high occupational activity. Research on the underlying causes to the contrasting effects of occupational and leisure time physical activity on cardiovascular health is lacking. The aim of this study was to examine the relation of objective and self-report measures of occupational and leisure time physical activity with 24-h ambulatory systolic blood pressure (BP). METHODS: Results for self-reported physical activity are based on observations in 182 workers (60% male, mean age 51 years), while valid objective physical activity data were available in 151 participants. The usual level of physical activity was assessed by 5 items from the Job Content Questionnaire (high physical effort, lifting heavy loads, rapid physical activity, awkward body positions and awkward positions of head or arms at work) and one item asking about the general level of physical activity during non-working time. On a regular working day, participants wore an ambulatory BP monitor and an accelerometer physical activity monitor during 24 h. Associations were examined by means of Analysis of Covariance. RESULTS: Workers with an overall high level of self-reported occupational physical activity as well as those who reported to often lift heavy loads at work had a higher mean systolic BP at work, at home and during sleep. However, no associations were observed between objectively measured occupational physical activity and BP. In contrast, those with objectively measured high proportion of moderate and vigorous leisure time physical activity had a significantly lower mean systolic BP during daytime, while no differences were observed according to self-reported level of leisure time physical activity. CONCLUSIONS: These findings suggest that workers reporting static occupational physical activities, unlike general physically demanding tasks characterized by dynamic movements of large muscle groups, are related to a higher daily systolic BP, while high objective levels of moderate and vigorous leisure time physical activity are related to lower daytime systolic BP. Ambulatory systolic BP may be a physiological explanatory factor for the contrasting effects of occupational and leisure time physical activity.

Comparison of alternative versions of the job demand-control scales in 17 European cohort studies: the IPD-Work consortium.

BACKGROUND: Job strain (i.e., high job demands combined with low job control) is a frequently used indicator of harmful work stress, but studies have often used partial versions of the complete multi-item job demands and control scales. Understanding whether the different instruments assess the same underlying concepts has crucial implications for the interpretation of findings across studies, harmonisation of multi-cohort data for pooled analyses, and design of future studies. As part of the 'IPD-Work' (Individual-participant-data meta-analysis in working populations) consortium, we compared different versions of the demands and control scales available in 17 European cohort studies. METHODS: Six of the 17 studies had information on the complete scales and 11 on partial scales. Here, we analyse individual level data from 70 751 participants of the studies which had complete scales (5 demand items, 6 job control items). RESULTS: We found high Pearson correlation coefficients between complete scales of job demands and control relative to scales with at least three items (r > 0.90) and for partial scales with two items only (r = 0.76-0.88). In comparison with scores from the complete scales, the agreement between job strain definitions was very good when only one item was missing in either the demands or the control scale (kappa > 0.80); good for job strain assessed with three demand items and all six control items (kappa > 0.68) and moderate to good when items were missing from both scales (kappa = 0.54-0.76). The sensitivity was > 0.80 when only one item was missing from either scale, decreasing when several items were missing in one or both job strain subscales. CONCLUSIONS: Partial job demand and job control scales with at least half of the items of the complete scales, and job strain indices based on one complete and one partial scale, seemed to assess the same underlying concepts as the complete survey instruments.

The perception of work stressors is related to reduced parasympathetic activity.

PURPOSE: The aim was to examine the perception of work stressors in relation to ambulatory measures of heart rate variability (HRV). METHODS: Results are based on a sample of 653 healthy male workers aged 40-55 from the Belgian Physical Fitness Study conducted in 1976-1978. Data were collected by means of self-administered questionnaires and bio-clinical examinations. An index of physical and psychosocial work stressors containing five items was constructed based on the job stress questionnaire. Data on HRV were collected by means of 24-h ambulatory ECG recordings on a working day. Both time and frequency domain measures of HRV were calculated. Associations between work stressors and HRV measures were assessed by means of correlations, multiple linear regression analysis and analysis of (co)variance. RESULTS: The work stressor index was significantly associated with lower pNN50 (the percentage of differences between adjacent normal RR intervals > 50 ms), lower high frequency power and a higher ratio of low frequency over high frequency power. Very similar results were obtained after adjusting for age, language, occupation, smoking, body mass index, total cholesterol, systolic blood pressure and leisure time physical activity. No significant associations were found with SDNN (the standard deviation of all normal RR intervals) and low frequency power. CONCLUSIONS: The perception of work stressors was related to reduced parasympathetic activity in a sample of 653 healthy male workers. These findings support the idea that particularly the parasympathetic component of the autonomic nervous system is related to work stress.

Gender specificity in the prediction of clinically diagnosed depression. Results of a large cohort of Belgian workers.

BACKGROUND: The recent increase in the incidence of clinical depression represents a major public health and socio-economical burden. Depression has its roots in both professional and private domains but few epidemiological studies have looked at predictors of long term clinical depression as defined by a sick-leave of 28 days or more and a diagnosis by a general practitioner in both genders. OBJECTIVES: To study baseline predictors of long term spells of clinical depression within the framework of a large prospective study, the Belstress Study, in 6,659 men and 2,737 women aged 35-59 years at baseline survey. METHODS: Kaplan-Meyer survival curves and Cox regression models were used in order to relate long term clinical depression defined by a sick-leave of 28 days or more to baseline socio-demographic and work and non-work variables. RESULTS AND CONCLUSIONS: Density incidence of long term clinical depression is 0.5 years and 1.1/1,000 persons/months for men and women respectively. In univariate analyses specific gender predictors were observed as for men predictors besides level of education, were work related: high job-strain OR 1.67 (CI 95% 1.03; 2.71) and work dissatisfaction OR 1.78 (CI 95% 1.09; 2.91) whereas for women baseline predictors are related to private life dissatisfaction OR 1.84 (CI 95% 1.16; 2.91) and to a lesser degree low social support from co-workers OR 1.50 (CI 95% 0.93; 2.40). In both genders baseline severe depression symptoms defined by a CES-D score of percentile 90 or above is a predictor of long term sick-leave for clinical depression. In multivariate analyses, in a model without baseline CES-D high job-strain and job dissatisfaction remain independent predictors for incident clinical depression in men whereas only private life dissatisfaction remains a significant predictor in women. When added to the model CES-D is the most powerful predictor of clinical depression in both genders. Together with level of education, work dissatisfaction remains borderline significant in men whereas private life dissatisfaction remains an independent predictor for clinical depression in women. In men baseline symptoms of depression alleviate the impact of high job-strain on incident clinical depression whereas in women, private life dissatisfaction remains an independent predictor of clinical depression.

High job strain and ambulatory blood pressure in middle-aged men and women from the Belgian job stress study.

OBJECTIVE: The aim of this study was to assess whether job strain is associated with 24-hour ambulatory blood pressure measurements within a subsample of the Belgian Job Stress Project (BELSTRESS) population. METHODS: A group of 89 middle-aged male and female workers perceiving high job strain and an equally large group of workers perceiving no high job strain wore an ambulatory blood pressure monitor for 24 hours on a regular working day. RESULTS: Mean ambulatory blood pressure at work, at home, and while asleep was significantly higher in workers with job strain as compared with others. The associations between job strain and ambulatory blood pressure were independent from the covariates. CONCLUSIONS: Within this study, high job strain was an important independent risk factor for higher ambulatory blood pressure at work, at home, and during sleep in a group of men and women.

Job stress and depression symptoms in middle-aged workers--prospective results from the Belstress study.

OBJECTIVE: The aim of this study was to explore the prospective relation between job stress and symptoms of depression within a cohort study. METHODS: Altogether 2821 workers were involved in the longitudinal Belstress study (Belgian job stress study); there were two measurements with a mean follow-up time of 6.6 years. Job stress was assessed by the Job Content Questionnaire. Depression symptoms were assessed by the Iowa form of the Center for Epidemiological Studies-Depression Scale. Baseline and repeated exposures to job stress were related to the development of high levels of depression symptoms through logistic regression analysis. RESULTS: Within a population free of high depression scores at baseline, job stress increased the risk of developing high levels of depression symptoms after a mean follow-up time of 6.6 years. Independent associations were found for low decision latitude, high job strain, and isolated strain among women, but not among men. The adjusted association with high job strain among men was borderline significant. Repeated high job strain was associated with a more elevated risk of developing high levels of depression symptoms among both the women and the men. CONCLUSIONS: The results of this study confirm that job stress is a risk factor for developing symptoms of depression. Stronger associations were found for women. The impact of high job strain among both men and women was more harmful when there was repeated exposure.

Long-term changes in the perception of job characteristics: results from the Belstress II--study.

The aim was to explore long-term changes in the perception of job characteristics--based on the Job Content Questionnaire (JCQ)--in view of the changing labor market in Western societies. A total number of 2,821 workers from nine companies were involved in the longitudinal Belstress-project. Data were gathered on two occasions with a mean time interval of 6.6 yr. At both times, participants completed the JCQ which measures the perception of job demands, job control and social support. In addition, the instrument contains questions regarding physical job demands, job insecurity and impact of world market competition (WMC). Changes over time in the perception of the different dimensions of the JCQ were evaluated within a sample of 2,490 respondents who remained in the same job. A statistically significant long-term stability of all JCQ scales was found. As far as intra-individual changes over time are concerned, the population showed a modest average increase in the perception of job demands, control and support of approximately 3%. Long-term changes in the other scales were larger, with an average increase of 10.3% in job insecurity and 15.5% in impact of WMC. Substantial variation in these two scales was found at the level of the company and in some socio-demographic factors. While perceived job characteristics remained relatively stable over an average period of 6.6 yr, a substantial increase was noted in job insecurity and the impact of WMC. These dimensions are becoming increasingly important within the context of economic globalization and labor market flexibility.