Workplace bullying and risk of suicide and suicide attempts: A register-based prospective cohort study of 98 330 participants in Denmark

OBJECTIVES

The aim of this study was to analyze whether individuals reporting exposure to workplace bullying had a higher risk of suicidal behavior, including both suicide attempt and death by suicide, than those not reporting such exposure.

METHODS

Using a prospective cohort study design, we linked data from nine Danish questionnaire-based surveys (2004-2014) to national registers up to 31 December 2016. Exposure to workplace bullying was measured by a single item. Suicide attempts were identified in hospital registers and death by suicide in the Cause of Death Register. Among participants with no previous suicide attempts, we estimated hazard ratios (HR) and 95% confidence intervals (CI), adjusting for sex, age, marital status, socioeconomic status, and history of psychiatric morbidity.

RESULTS

The sample consisted of 98 330 participants (713 798 person-years), 63.6% were women, and the mean age was 44.5 years. Of these participants, 10 259 (10.4%) reported workplace bullying. During a mean follow-up of 7.3 years, we observed 184 cases of suicidal behavior, including 145 suicide attempts, 35 deaths by suicide and 4 cases that died by suicide after surviving a suicide attempt. The fully-adjusted HR for the association between workplace bullying and suicidal behavior was 1.65 (95% CI 1.06-2.58). The HR for suicide attempts and death by suicide were 1.65 (1.09-2.50) and 2.08 (0.82-5.27), respectively. Analyses stratified by sex showed a statistically significant association between workplace bullying and suicidal behavior among men but not women.

CONCLUSIONS

The results suggest that exposure to workplace bullying is associated with an elevated risk of suicidal behavior among men.

Labour market affiliation among non-bullied colleagues at work units with reported bullying

AIM

This study investigates if non-bullied employees in Work units (WUs) where bullying occur, are more prone to leave the WUs than employees in WUs with no bullying, and if the prevalence of workplace bullying had an impact on leaving the WUs. Leaving the workplace was defined by unemployment or change of workplace at follow-up.

METHODS

We had data from 8326 Danish public health invited employees from 302 WUs. Of these 3036 responded to a questionnaire on working conditions and health in 2007. WUs were classified into three categories of WUs: (1) no bullying (0% bullied), (2) moderate prevalence of bullying (< 10% bullied), and (3) high prevalence of bullying (≥ 10% bullied). Bullied respondents were used to classify the WUs and excluded in the analyses.

RESULTS

We found odds ratios (ORs) for unemployment 1 year later of 1.27 [95% CI 0.69-2.37] in WUs with moderate prevalence of bullying and 1.38 [95% CI 0.85-2.23] among employed in WUs with high prevalence of bullying, adjusted for size of WUs, age, sex, and job category. For turnover 1 year later the ORs were 1.27 [95% CI 0.78-2.15] and 1.46 [95% CI 0.99-2.15] in WUs with moderate and high prevalence of bullying, respectively.

CONCLUSION

We did not find that non-bullied employees leave the WUs with moderate and high prevalence of bullying more than employees in WUs with no bullying behaviour 1 year later. Leaving the workplace tended to be higher among employees in WUs with high prevalence of bullying compared to no and moderate bullying.

Perceived stress and dementia: Results from the Copenhagen city heart study

Objectives: We investigated if perceived stress in midlife increased the risk of dementia. Furthermore, we explored differences between subgroups related to sex, age and employment status when reporting stress.Methods: In this longitudinal study, we used information on perceived stress from 10,814 participants (mean age 56.7 years). Participants were followed through Danish national registers for development of dementia. Participants were considered at risk of dementia from the date they turned 60 years. Perceived stress was assessed as a combination of self-reported intensity and frequency of stress, and categorized into low (score 0-1), medium (score 2-4), and high stress (score 5-6). We used Poisson regression to estimate incidence rate ratios (IRR) and their 95% confidence intervals (CI) and adjusted for sociodemographic factors and psychiatric morbidity at baseline (main model) as well as cardio/cerebrovascular diseases and health behaviors at baseline (additional model).Results: The mean follow-up time was 13.8 years, and 1,519 participants were registered with dementia. Dementia risk was higher in participants reporting medium stress (IRR = 1.11, 95% CI: 0.99-1.24) and high stress (IRR = 1.36, 95% CI: 1.13-1.65). Adjustment for cardio/cerebrovascular diseases and health behaviors did not alter the results. We did not find strong support for differences between subgroups, although the association between stress and dementia was stronger for those who were employed at the time of reporting high stress.Conclusion: Our results provide empirical support for an effect of perceived stress on the risk of dementia in old age.

Physical and psychosocial work factors as explanations for social inequalities in self-rated health

OBJECTIVE

We investigated the contribution of physical and psychosocial work factors to social inequalities in self-rated health (SRH) in a sample of Danish 40 and 50 years old occupationally active women and men.

METHODS

In this longitudinal study, the study population consisted of 3338 Danish women and men. Data were collected by postal questionnaires in 2000 (baseline) and 2006 (follow-up). The independent variable, socioeconomic position (SEP), was assessed by the highest achieved educational level at baseline. We conducted gender-stratified parallel multiple mediation analyses. In the mediation analyses, SEP was categorised as SEP I, II, III, VI and V among men. Among women, SEP was dichotomised into SEP I-IV and V. The outcome, SRH, was assessed at baseline and follow-up. A wide range of physical and psychosocial work factors were included as potential mediators.

RESULTS

We found a social gradient in SRH across all levels of SEP among men. Among women, we only found a poorer SRH among those with the lowest SEP. Mediation analyses showed that work factors together accounted for 56% of the social inequalities in SRH among men and 44% among women. In both genders, ergonomic exposures and job insecurity seemed to play the major role for social inequalities in SRH. For women only, we also found noise to contribute to the social inequalities in SRH.

CONCLUSION

Physical and psychosocial work factors partially explained social inequalities in SRH among both genders. Improvement of the working environment can potentially contribute to the reduction of social inequalities in health.

Vital Exhaustion and Incidence of Dementia: Results from the Copenhagen City Heart Study

BACKGROUND

Psychological distress is potentially linked to the risk of dementia through neurologic and cardiovascular mechanisms. Vital exhaustion (VE) is a mental state of psychological distress, which could be a risk factor for dementia.

OBJECTIVE

To investigate whether VE is a risk factor for dementia in later life.

METHODS

We used data from 6,807 participants attending the third survey of the Copenhagen City Heart Study in 1991-1994. VE was assessed by 17 symptoms (score: 0-17) from the Maastricht Questionnaire. Information on dementia was obtained from national registers. Risk time for dementia was counted from five years after VE assessment for participants > 55 years at the time of VE assessment. For younger participants, risk time for dementia was counted from the year they turned 60 years and onwards. Participants were followed until 2016. We used Poisson regression to calculate incidence rate ratios (IRR) and their 95% confidence intervals (CI).

RESULTS

During an average follow-up of 10 years, 872 participants were registered with dementia. We found a dose-response relation between the number of VE symptoms and the incidence of dementia. For every additional VE symptom, the dementia incidence increased by 2% (IRR = 1.024; 95% CI: 1.004-1.043). Adjustment for socio-demographic and health-related factors did not change the results substantially. Neither did stratification by age, sex, educational level, and marital status.

CONCLUSION

We found evidence that VE is a risk factor for dementia. Our sensitivity analyses supported that this association was not only due to VE being a potential prodromal sign of dementia.

Midlife Forgetfulness and Risk of Dementia in Old Age: Results from the Danish Working Environment Cohort Study

BACKGROUND

Despite the current evidence of a high prevalence of forgetfulness in middle-aged individuals, and the evidence of a link between midlife memory complaints and biological changes in the brain, no previous study has yet investigated midlife forgetfulness in relation to risk of dementia in old age.

AIMS

We investigated whether midlife forgetfulness was an indicator of an increased risk of dementia in old age.

METHODS

We used data from 3,136 employed men and women who participated in the Danish Work Environment Cohort Study in 1990. These data were linked to Danish national registers. Participants were asked whether their closest relative had ever told them that they were forgetful. Incidence rate ratios (IRR) were estimated using Poisson regression analysis.

RESULTS

At baseline, 749 (24%) study participants were categorized as forgetful, and 86 (2.7%) participants were diagnosed with dementia during a total of 31,724 person-years at risk. After adjusting for sociodemographic factors, comorbidities, and work-related factors, midlife forgetfulness was associated with a higher risk of dementia (IRR = 1.82; 95% CI: 1.12-2.97).

CONCLUSIONS

This study is the first to investigate midlife forgetfulness and dementia, and the results suggest that midlife forgetfulness is an early indicator of an increased risk of dementia in old age.

The longitudinal association between shift work and headache: results from the Danish PRISME cohort

PURPOSE

We investigated the effect of shift work on headache. Furthermore, we investigated whether the association between shift work and headache was explained by potential mediators in terms of perceived stress, poor sleep and health behaviors.

METHODS

In this longitudinal study, we used questionnaire data (collected in 2007 and 2009) from civil servants and hospital employees from the PRISME study. 2952 individuals were available for the analyses of shift work and headache and 2272 individuals were available for the analyses of shift work and migraine. Headache was operationalized as the participants' experience of "being bothered by headache during the past 4 weeks". Migraine was operationalized as "ever being diagnosed with migraine by a medical doctor". We used binary logistic regression to compare shift workers with permanent day workers and adjusted for socio-demographic factors. In a subsequent step, we adjusted for potential mediators.

RESULTS

We found higher odds of unspecific headache (OR = 1.25; 95% CI 1.02-1.54) and migraine (OR = 1.72; 95% CI 1.04-2.86) among shift workers compared with day workers. Our results suggest that the effect of shift work on headache and migraine differ between men and women. Inclusion of potential mediators in the analyses did not attenuate the associations.

CONCLUSION

Shift workers have higher risk of reporting being bothered by headache as well as reporting being diagnosed with migraine. Future research is needed to disentangle the underlying mechanisms with the aim of reducing headache related to occupational exposures.

Night shift work, long working hours and dementia: a longitudinal study of the Danish Work Environment Cohort Study

OBJECTIVE

Shift work and long working hours are potential risk factors for dementia, but previous studies on shift work, long working hours and dementia are sparse and their findings are conflicting. Therefore, we investigated the effect of night shift work and long working hours on dementia.

DESIGN

A longitudinal study.

SETTING

Denmark.

PARTICIPANTS

3435 occupationally active men and women from the general working population.

METHODS

Work schedule covered day work (reference) and shift schedules without/with night work. Working hours covered <27, 28-36, 37 (reference), 38-44, and ≥45 hours/week. As the primary outcome, we used register-based information about dementia, and estimated incidence rate ratios (IRR) and 95% CI. Estimates were adjusted for gender, age, psychosocial work factors and cardiovascular risk factors.

RESULTS

We identified 85 dementia cases during a mean of 9.8 years of follow-up. We found a positive, but statistically insignificant association between night shift work and dementia (IRR=2.01; 95% CI: 0.87-4.65). Post hoc analyses indicated that this was only due to a higher risk in permanent night workers (IRR=3.25; 95% CI: 1.35-7.83). The dementia risk was also significantly higher among participants working 38-44 hours/week (IRR=2.08; 95% CI: 1.11-3.90) compared with those working 37 hours/week. We found no indications of a higher risk of dementia in participants working <37 hours/week or ≥45 hours/week.

CONCLUSION

We did not find arguments that night shift work or long working hours increased dementia risk in general. However, we found a higher risk of dementia in specific subgroups, that is, permanent night workers and employees with moderately longer weekly working hours than the standard.

The associations between workplace bullying, salivary cortisol, and long-term sickness absence: a longitudinal study

BACKGROUND

Workplace stressors, such as bullying, are strongly related to subsequent long-term sickness absence, but little is known of the possible physiological mechanisms linking workplace stressors and sickness absence. The primary aim of this study was to investigate to what extent cortisol levels were associated with subsequent sickness absence and if cortisol mediated the association between workplace bullying and sickness absence. We additionally investigated possible bidirectional associations between bullying, cortisol, and long-term sickness absence.

METHODS

Participants came from two Danish cohort studies, the "Psychosocial RIsk factors for Stress and MEntal disease" (PRISME) cohort and the "Workplace Bullying and Harassment" (WBH) cohort (n = 5418). Information about exposure to workplace bullying and morning and evening salivary cortisol was collected at three time points with approximately two years in between. After each data collection, all participants were followed for two years in registers, and cases with long-term sickness absence lasting 30 or more consecutive days were identified. The association between cortisol levels and subsequent sickness absence was assessed by logistic regression, while the extent to which the association between bullying and sickness absence was mediated by cortisol was quantified through natural direct and indirect effects.

RESULTS

High evening cortisol was associated with a decreased risk of sickness absence (OR = 0.82, 95% CI = 0.68-0.99), but we did not find that high morning cortisol levels (OR = 0.98, 95% CI = 0.81-1.18) or high morning-to-evening slope (OR = 0.99, 95% CI = 0.82-1.18) were associated with subsequent sickness absence. We also tested for reverse causation and found that long-term sickness absence, but not salivary cortisol, was a strong risk factor for subsequent workplace bullying. There was no indication that cortisol mediated the association between workplace bullying and sickness absence.

CONCLUSION

We found no straightforward and simple association between cortisol and long-term sickness absence. Furthermore, the association between workplace bullying and long-term sickness absence was not mediated by cortisol.

Prolonged perceived stress and saliva cortisol in a large cohort of Danish public service employees: cross-sectional and longitudinal associations

Purpose

It is well known that acute stress can lead to a transient increase in cortisol secretion, but the effects of prolonged stress on cortisol secretion are uncertain. This study examines the cross-sectional and longitudinal associations between prolonged perceived stress and salivary cortisol.

Methods

In 2007, 4467 Danish public service employees participated in a study of stress and mental health, and 3217 participated in a follow-up in 2009. Perceived stress during the past 4 weeks was assessed by Cohen’s four item perceived stress scale. Participants were asked to collect saliva 30 min after awakening and at approximately 20:00 in the evening. The cortisol dependence on perceived stress was examined in regression analyses adjusted for effects of potential confounders. We adjusted for a large variation in saliva sampling times by modelling the time trajectory of cortisol concentrations in the morning and in the evening and examined if they were influenced by perceived stress.

Results

Perceived stress had no statistically significant effects on the level or time trajectory of morning or evening cortisol, neither cross-sectionally nor longitudinally. The 1 month prevalence of frequently perceived stress was low, approximately 2.5%.

Conclusion

Our results did not support the hypothesis that prolonged perceived stress is associated with the level or time trajectory of morning or evening salivary cortisol.

Electronic supplementary material

The online version of this article (doi:10.1007/s00420-017-1241-z) contains supplementary material, which is available to authorized users.

The association between workplace bullying and depressive symptoms: the role of the perpetrator

Background

The aim of the present study was to investigate whether the depressive symptoms of the bullied respondents differed according to who the perpetrator was.

Methods

We used cross-sectional questionnaire data from two representative cohorts: the Danish Working Environment Cohort Study (DWECS 2010) and the Work and Health Study (WH 2012). After excluding respondents not having a leader, or being self-employed, assisting spouses, and those reporting multiple perpetrators in WH 2012, the statistical analysis included 2478 bullied individuals. We compared respondents reporting being bullied by their (1) leader, (2) subordinates, (3) clients / customers / patients / students, or (4) colleagues, respectively. The occurrence of depressive symptoms was measured by the Major Depression Inventory (MDI).

Results

The most frequent perpetrator of bullying was clients (41.5 %) in DWECS 2010 and colleagues (60.3 %) in WH 2012. In DWECS 2010, the MDI score of those being bullied by clients were significantly lower than the MDI scores of the other groups. In WH 2012, respondents who reported bullying from leaders had a significantly higher mean MDI score than participants being bullied by colleagues. Also in WH 2012, our results indicated that those who were bullied by leaders had a higher MDI score than those bullied by clients, although this difference was not statistically significant at conventional levels.

Conclusion

Our findings indicated a similar pattern in the two cohorts, with a tendency of more severe depressive symptoms among employees who are exposed to bullying by their leaders, and the least severe symptoms among those who are bullied by clients.

The role of poor sleep in the relation between workplace bullying/unwanted sexual attention and long-term sickness absence

PURPOSE

While exposure to bullying and unwanted sexual attention was previously found to increase the risk of sickness absence, the underlying mechanisms are largely unknown. Poor sleep can be a consequence of stressful exposures and a cause of poor health, and poor sleep is also a determinant of insufficient recovery. Therefore, the present study investigated whether poor sleep mediates and/or moderates the association between bullying and unwanted sexual attention, on the one hand, and long-term sickness absence (LTSA), on the other hand.

METHODS

We used questionnaire data from 7650 individuals contributing with 15,040 2-year observation periods. Workplace bullying, unwanted sexual attention, disturbed sleep, and difficulties awakening were measured at three time points, and participants were followed in registers to measure the occurrence of LTSA, defined as ≥30 consecutive days of sickness absence during the subsequent 2 years.

RESULTS

The odds of LTSA were significantly increased by workplace bullying (OR 1.77; 95 % CI 1.50-2.12) and unwanted sexual attention (OR 1.55; 95 % CI 1.06-2.29). Together, disturbed sleep and difficulties awakening mediated 12.8 % (95 % CI 8.1-19.8) of the association between bullying and long-term sickness absence, and 8.5 % (95 % CI -0.45 to 37.1) of the association between unwanted sexual attention and long-term sickness absence in the fully adjusted model. Neither disturbed sleep nor difficulties awakening moderated these associations.

CONCLUSION

As expected, bullying and unwanted sexual attention were prospectively associated with long-term sickness absence. Only a small part of this association was mediated by poor sleep.

Workplace bullying, sleep problems and leisure-time physical activity: a prospective cohort study

OBJECTIVES

Workplace bullying is a potent stressor that may increase sleep problems. Since physical fitness improves resilience to stress, it seems plausible that recreational physical activities may moderate the association between bullying and sleep. The study aimed to examine prospectively whether (i) bullying increases the risk of sleep problems, and (ii) the association between bullying and sleep problems is moderated by leisure-time physical activity (LTPA).

METHODS

The study sample comprised a cohort of public and private sector employees, who were enrolled into the Work Bullying and Harassment (WBH) cohort (N=3278) or the Psychosocial Risk Factors for Stress and Mental Disease (PRISME) cohort (N=4455). We measured workplace bullying using one question that was preceded by a definition of bullying. We used the Karolinska sleep questionnaire to assess sleep problems. The number of hours per week spent on LTPA estimated the degree of physical activity.

RESULTS

Workplace bullying at baseline (T1) was associated with awakening problems and lack of restful sleep at follow-up (T2) but not with overall sleep problems and disturbed sleep. T1-LTPA did not moderate the association between T1-workplace bullying and T2-sleep problems.

CONCLUSION

We found support that workplace bullying is related to development of T2-sleep problems, but this association seems not to be modified by LTPA.

Atherogenic risk factors and hearing thresholds

The objective of this study was to evaluate the influence of atherogenic risk factors on hearing thresholds. In a cross-sectional study we analyzed data from a Danish survey in 2009-2010 on physical and psychological working conditions. The study included 576 white- and blue-collar workers from children's day care units, financial services and 10 manufacturing trades. Associations between atherogenic risk factors (blood lipids, glycosylated hemoglobin, smoking habits, body mass index (BMI), and ambulatory blood pressure) and hearing thresholds were analyzed using multiple linear regression models. Adjusted results suggested associations between smoking, high BMI and triglyceride level and low high-density lipoprotein level and increased low-frequency hearing thresholds (average of pure-tone hearing thresholds at 0.25, 0.5 and 1 kHz). Furthermore, an increasing load of atherogenic risk factors seemed associated with increased low-frequency hearing thresholds, but only at a borderline level of statistical significance. Associations were generally strongest with hearing levels of the worst hearing ear. We found no statistically significant associations between atherogenic risk factors and high-frequency hearing thresholds (average of pure-tone hearing thresholds at 4, 6 and 8 kHz).

Salivary cortisol and depression in public sector employees: cross-sectional and short term follow-up findings

INTRODUCTION

Increased cortisol levels have been suggested to play a role in the development of depression. An association has been shown in some studies but not consistently. The timing of an association is uncertain, and long-term follow-up studies may miss associations in narrower time windows. In the present study, we examined the association of several cortisol measures and depression in a repeated cross-sectional and short-term follow-up design. Depression was assessed by both self-reported symptoms of depression and clinical interviews.

METHOD

In 2007, 10,036 public sector employees received a questionnaire along with salivary cortisol test tubes for home administration. Morning (30min after awakening) and evening (2000h) salivary samples were collected. Questionnaires and valid saliva samples were returned from 3536 employees. Approximately 3.6 months later a subsample of the participants collected three morning saliva samples (at awakening, 20min and 40min after awakening) plus an evening sample (2000h); participants with high baseline scores of self-reported depressive symptoms, burnout and perceived stress were invited to a standardized interview (SCAN) to detect clinical depression; and the symptom questionnaire was repeated for subsample participants. The study was repeated in 2009 with questionnaires and salivary test tubes (n=2408). In four cross-sectional and two short-term follow-up analyses odds ratios of depressive symptoms and of clinical depression were estimated by logistic regression for morning, evening, mean and the difference between morning and evening cortisol (slope). For the subsample, awakening response (CAR) and area under the curve (AUC) cortisol measures were calculated. We adjusted for sex, age, income, education, family history of depression, physical activity and alcohol consumption.

RESULTS

None except one of the measures of salivary cortisol were associated with self-reported depressive symptoms or clinical depression, neither in the four cross-sectional analyses nor in the two short term follow-up analyses. E.g. in 2007, the adjusted odds ratios (OR) of depressive symptoms by a one unit increase in morning and evening cortisol (ln(nmol/litre saliva)) were 1.01 (95% CI: 0.88-1.17) and 1.05 (0.93-1.18), respectively. The one exception was significant at p=0.04 and was considered as due to chance.

CONCLUSION

In this large study, salivary cortisol was not associated with self-reported symptoms of depression or with clinical depression.

Recent and long-term occupational noise exposure and salivary cortisol level

Environmental and occupational noise exposure have been related to increased risk of cardiovascular disease, hypothetically mediated by stress-activation of the hypothalamic-pituitary-adrenal (HPA) axis. The objective of this study was to investigate the relation between recent and long-term occupational noise exposure and cortisol level measured off work to assess a possible sustained HPA-axis effect. We included 501 industrial, finance, and service workers who were followed for 24h during work, leisure, and sleep. Ambient occupational noise exposure levels were recorded every 5s by personal dosimeters and we calculated the full-shift LAEq value and estimated duration and cumulative exposure based on their work histories since 1980. For 332 workers who kept a log-book on the use of hearing protection devices (HPD), we subtracted 10 dB from every noise recording obtained during HPD use and estimated the noise level at the ear. Salivary cortisol concentration was measured at 20.00 h, the following day at awakening, and 30 min after awakening on average 5, 14 and 14.5h after finishing work. The mean ambient noise exposure level was 79.9 dB(A) [range: 55.0-98.9] and the mean estimated level at the ear 77.7 dB(A) [range: 55.0-94.2]. In linear and mixed regression models that adjusted for age, sex, current smoking, heavy alcohol consumption, personal income, BMI, leisure-time noise exposure level, time since occupational noise exposure ceased, awakening time, and time of saliva sampling, we observed no statistically significant exposure response relation between recent, or long-term ambient occupational noise exposure level and any cortisol parameter off work. This was neither the case for recent noise level at the ear. To conclude, neither recent nor long-term occupational noise exposure levels were associated with increased cortisol level off work. Thus, our results do not indicate that a sustained activation of the HPA axis, as measured by cortisol, is involved in the causal pathway between occupational noise exposure and cardiovascular disease.

A two-year follow-up study of salivary cortisol concentration and the risk of depression

Stress is a suspected cause of depression. High cortisol concentration, a biomarker of an activated stress response, has been found in depressed patients. The aim of this study was to determine if a high level of salivary cortisol is a risk factor of depression. In 2007, we enrolled 4467 public employees. Morning and evening salivary cortisol concentration were measured for each participant. Participants reporting high levels of depressive, burnout, or stress symptoms, assessed by questionnaires were assigned to a psychiatric interview. In this interview 98 participants were diagnosed with depression and subsequently excluded. Two years later in 2009, 2920 participants who had provided at least one valid saliva cortisol measurement at baseline participated at follow up. The psychiatric interviews were repeated and 62 cases of newly onset depression were diagnosed. Odds ratios of depression were estimated for every 1.0nmol/l increase in morning, evening, and daily mean cortisol concentration, as well as for the difference between morning and evening cortisol concentration. The risk of depression decreased by increasing daily mean cortisol concentration and by increasing difference between morning and evening concentrations, while morning and evening cortisol concentrations were not significantly associated with depression. The adjusted odds ratios for 1.0nmol/l increase in morning, evening, and daily mean cortisol concentration were 0.69 (95% CI: 0.45, 1.05), 0.87 (95% CI: 0.59, 1.28), and 0.53 (95% CI: 0.32, 0.90), respectively. The adjusted odds ratio for 1.0nmol/l increase in difference between morning and evening concentration were 0.64 (95% CI: 0.45, 0.90). This study did not support the hypothesis that high salivary cortisol concentration is a risk factor of depression, but indicate that low mean salivary cortisol concentration and a small difference between morning and evening cortisol concentration may be risk factors of depression.

Work-unit measures of organisational justice and risk of depression--a 2-year cohort study

OBJECTIVES

The aim of this study is to analyse if low justice at work, analysed as aggregated workplace means, increases the risk of depression.

METHODS

A total of 4237 non-depressed Danish public employees within 378 different work units were enrolled in 2007. Mean levels of procedural and relational justice were computed for each work unit to obtain exposure measures that were robust to reporting bias related to depression. Two years later in 2009, 3047 (72%) participated at follow-up. Those reporting high levels of depressive, burn-out or stress symptoms were assigned to a psychiatric diagnostic interview. In the interview 58 cases of new onset depression were identified. Depression ORs by work unit level of procedural and relational justice were estimated by multivariable logistic regression accounting for established risk factors for depression.

RESULTS

Working in a work unit with low procedural justice (adjusted ORs of 2.50, 95% CI 1.06 to 5.88) and low relational justice (3.14, 95% CI 1.37 to 7.19) predicted onset of depression.

CONCLUSIONS

Our results indicate that a work environment characterised by low levels of justice is a risk factor for depression.

A two-year follow-up study of risk of depression according to work-unit measures of psychological demands and decision latitude

OBJECTIVES

The aim of this study was to examine if high psychological demands and low decision latitude at work increase the risk of depression.

METHODS

In 2007, 4237 non-depressed Danish public employees within 378 different work units were enrolled in the study. Mean levels of psychological demands and decision latitude were computed for each work unit to obtain exposure measures that were robust to reporting bias. In 2009, 3046 (72%) participated at follow-up, and those reporting high levels of depressive, burnout or stress symptoms went through a psychiatric interview by which 58 cases of new onset depression were diagnosed. Odds ratios (OR) of depression for different levels of work unit mean psychological demands and decision latitude were estimated by logistic regression taking established risk factors into account.

RESULTS

The OR for depression according to psychological demands was 1.07 [95% confidence interval (95% CI) 0.42-2.49] for every unit of change on a 5-point scale. The corresponding OR for decision latitude was 1.85 (95% CI 0.55-6.26). No interactive effects of psychological demands and decision latitude were observed.

CONCLUSION

These findings suggest that low decision latitude may predict depression, but confidence intervals are wide and findings are also compatible with no increased risk.