Cumulative exposure to high-strain and active jobs as predictors of cognitive function: the Whitehall II study

An urgent call to address work-related psychosocial hazards and improve worker well-being

Work-related psychosocial hazards are on the verge of surpassing many other occupational hazards in their contribution to ill-health, injury, disability, direct and indirect costs, and impact on business and national productivity. The risks associated with exposure to psychosocial hazards at work are compounded by the increasing background prevalence of mental health disorders in the working-age population. The extensive and cumulative impacts of these exposures represent an alarming public health problem that merits immediate, increased attention. In this paper, we review the linkage between work-related psychosocial hazards and adverse effects, their economic burden, and interventions to prevent and control these hazards. We identify six crucial societal actions: (1) increase awareness of this critical issue through a comprehensive public campaign; (2) increase etiologic, intervention, and implementation research; (3) initiate or augment surveillance efforts; (4) increase translation of research findings into guidance for employers and workers; (5) increase the number and diversity of professionals skilled in preventing and addressing psychosocial hazards; and (6) develop a national regulatory or consensus standard to prevent and control work-related psychosocial hazards.

The effects of work on cognitive functions: a systematic review

Introduction

Cognitive functions play a crucial role in individual's life since they represent the mental abilities necessary to perform any activity. During working life, having healthy cognitive functioning is essential for the proper performance of work, but it is especially crucial for preserving cognitive abilities and thus ensuring healthy cognitive aging after retirement. The aim of this paper was to systematically review the scientific literature related to the effects of work on cognitive functions to assess which work-related factors most adversely affect them.

Method

We queried the PubMed and Scopus electronic databases, in February 2023, according to the PRISMA guidelines (PROSPERO ID number = CRD42023439172), and articles were included if they met all the inclusion criteria and survived a quality assessment. From an initial pool of 61,781 papers, we retained a final sample of 64 articles, which were divided into 5 categories based on work-related factors: shift work (n = 39), sedentary work (n = 7), occupational stress (n = 12), prolonged working hours (n = 3), and expertise (n = 3).

Results

The results showed that shift work, occupational stress, and, probably, prolonged working hours have detrimental effects on cognitive functioning; instead, results related to sedentary work and expertise on cognitive functions are inconclusive and extremely miscellaneous.

Discussion

Therefore, workplace health and well-being promotion should consider reducing or rescheduling night shift, the creation of less demanding and more resourceful work environments and the use of micro-breaks to preserve workers' cognitive functioning both before and after retirement.

Systematic review registration

https://www.crd.york.ac.uk/prospero/display_record.php?ID=CRD42023439172, identifier CRD42023439172.

Dysfunction of large-scale brain networks underlying cognitive impairments in shift work disorder

It has been demonstrated that shift work can affect cognitive functions. Several neuroimaging studies have revealed altered brain function and structure for patients with shift work disorder (SWD). However, knowledge on the dysfunction of large-scale brain networks underlying cognitive impairments in shift work disorder is limited. This study aims to identify altered functional networks associated with cognitive declines in shift work disorder, and to assess their potential diagnostic value. Thirty-four patients with shift work disorder and 36 healthy controls (HCs) were recruited to perform the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) and resting-state functional scans. After surface-based preprocessing, we calculated within- and between-network functional connectivity (FC) using the Dosenbach atlas. Moreover, correlation analysis was done between altered functional connectivity of large-scale brain networks and scores of cognitive assessments in patients with shift work disorder. Finally, we established a classification model to provide features for patients with shift work disorder concerning the disrupted large-scale networks. Compared with healthy controls, increased functional connectivity within-networks across the seven brain networks, and between-networks involving ventral attention network (VAN)-subcortical network (SCN), SCN-frontoparietal network (FPN), and somatosensory network (SMN)-SCN were observed in shift work disorder. Decreased functional connectivity between brain networks was found in shift work disorder compared with healthy controls, including visual network (VN)-FPN, VN-default mode network (DMN), SMN-DMN, dorsal attention network (DAN)-DMN, VAN-DMN, and FPN-DMN. Furthermore, the altered functional connectivity of large-scale brain networks was significantly correlated with scores of immediate memory, visuospatial, and delayed memory in patients with shift work disorder, respectively. Abnormal functional connectivity of large-scale brain networks may play critical roles in cognitive dysfunction in shift work disorder. Our findings provide new evidence to interpret the underlying neural mechanisms of cognitive impairments in shift work disorder.

Triangulating evidence from observational and Mendelian randomization studies of ketone bodies for cognitive performance

BACKGROUND

Ketone bodies (KBs) are an alternative energy supply for brain functions when glucose is limited. The most abundant ketone metabolite, 3-β-hydroxybutyrate (BOHBUT), has been suggested to prevent or delay cognitive impairment, but the evidence remains unclear. We triangulated observational and Mendelian randomization (MR) studies to investigate the association and causation between KBs and cognitive function.

METHODS

In observational analyses of 5506 participants aged ≥ 45 years from the Whitehall II study, we used multiple linear regression to investigate the associations between categorized KBs and cognitive function scores. Two-sample MR was carried out using summary statistics from an in-house KBs meta-analysis between the University College London-London School of Hygiene and Tropical Medicine-Edinburgh-Bristol (UCLEB) Consortium and Kettunen et al. (N = 45,031), and publicly available summary statistics of cognitive performance and Alzheimer's disease (AD) from the Social Science Genetic Association Consortium (N = 257,841), and the International Genomics of Alzheimer's Project (N = 54,162), respectively. Both strong (P < 5 × 10-8) and suggestive (P < 1 × 10-5) sets of instrumental variables for BOHBUT were applied. Finally, we performed cis-MR on OXCT1, a well-known gene for KB catabolism.

RESULTS

BOHBUT was positively associated with general cognitive function (β = 0.26, P = 9.74 × 10-3). In MR analyses, we observed a protective effect of BOHBUT on cognitive performance (inverse variance weighted: βIVW = 7.89 × 10-2, PIVW = 1.03 × 10-2; weighted median: βW-Median = 8.65 × 10-2, PW-Median = 9.60 × 10-3) and a protective effect on AD (βIVW =  - 0.31, odds ratio: OR = 0.74, PIVW = 3.06 × 10-2). Cis-MR showed little evidence of therapeutic modulation of OXCT1 on cognitive impairment.

CONCLUSIONS

Triangulation of evidence suggests that BOHBUT has a beneficial effect on cognitive performance. Our findings raise the hypothesis that increased BOHBUT may improve general cognitive functions, delaying cognitive impairment and reducing the risk of AD.

Psychosocial working conditions and cognitive and physical impairment in older age

BACKGROUND

Psychosocial working conditions are associated with cognitive and physical impairments. The aim of this study was to investigate the associations between mid-late life psychosocial working conditions and the combination of physical and cognitive impairment among older adults, and the potential sex differences in these associations.

METHODS

Data were derived from two Swedish nationally representative surveys (n = 839; follow-up: 20-24 years). Multinomial and binary logistic regressions assessed the associations between work stressors (job demand-control model), and a combination of cognitive and physical impairment.

RESULTS

Low control jobs were significantly associated with higher odds of cognitive (OR: 1.41, CI: 1.15-1.72) and physical impairment (OR: 1.23, CI: 1.02-1.47), and cognitive and physical impairment combined (OR: 1.50, CI: 1.19-1.89). Passive jobs (low control, low demand) were associated with higher odds of cognitive impairment (OR: 1.57, CI: 1.12-2.20), and combined cognitive and physical impairment (OR: 1.59, CI: 1.07-2.36). Active jobs (high control, high demand) were associated with lower odds of cognitive impairment (OR: 0.48, CI: 0.29-0.80). Sex-stratified analyses showed stronger associations among men; passive jobs were associated with both cognitive (OR: 2.18, CI: 1.31-3.63) and physical impairment (OR: 1.78, CI: 1.13-2.81), while low strain jobs were associated with less physical impairment (OR: 0.55, CI: 0.33-0.89). No significant associations between work stressors and impairment were found for women.

CONCLUSIONS

These results highlight the importance of psychosocial working conditions for late-life physical and cognitive impairment, especially among men. Jobs characterised by low control and low demands are associated with higher risk for impairments.

Psychosocial work environment as a dynamic network: a multi-wave cohort study

While characteristics of psychosocial work environment have traditionally been studied separately, we propose an alternative approach that treats psychosocial factors as interacting elements in networks where they all potentially affect each other. In this network analysis, we used data from a prospective occupational cohort including 10,892 participants (85% women; mean age 47 years) and repeated measurements of seven psychosocial work characteristics (job demands, job control, job uncertainty, team climate, effort-reward imbalance, procedural justice and interactional justice) assessed in 2000, 2004, 2008 and 2012. Results from multilevel longitudinal vector autoregressive models indicated that job demands as well as interactional and procedural justice were most broadly associated with the subsequent perceptions of the work-related psychosocial factors (high out-Strength), suggesting these factors might be potentially efficient targets of workplace interventions. The results also suggest that modifying almost any of the studied psychosocial factors might be relevant to subsequent perceptions of effort-reward imbalance and interactional justice at the workplace.

The Role of Executive Function in the Effectiveness of Multi-Component Interventions Targeting Physical Activity Behavior in Office Workers

A knowledge gap remains in understanding how to improve the intervention effectiveness in office workers targeting physically active (PA) behavior. We aim to identify the modifying effect of executive function (EF) on the intervention effectiveness targeting PA-behaviors, and to verify whether the observed effect varies by Job Demand Control (JDC) categories. This workplace-based intervention study included 245 participants who were randomized into a control group and two intervention arms-promoting physical activity (iPA) group or reducing sedentary behavior (iSED) group. The interventions were conducted through counselling-based cognitive behavioral therapy and team activities over 6 months. PA-behaviors were measured by an accelerometer. EF was assessed by the Trail Making Test-B, Stroop, and n-back test. The JDC categories were measured by the demand control questionnaire. Higher EF level at baseline was significantly associated with the intervention effect on increased sleep time (β-coefficient: 3.33, p = 0.003) and decreased sedentary time (-2.76, p = 0.049) in the iSED-group. Participants with active jobs (high job demands, high control) presented significantly increased light-intensity PA in the iSED-group in comparison to the control group. Among participants with a high level of EF and active jobs, relative to the control group, the iPA-group showed a substantial increase in light-intensity PA (1.58, p = 0.036) and the iSED-group showed a tendency of reducing sedentary behavior (-5.35, p = 0.054). The findings suggest that office workers with a high EF and active jobs may benefit most from an intervention study targeting PA-behaviors.

Association of mental demands in the workplace with cognitive function in older adults at increased risk for dementia

Objectives

Growing evidence suggests a protective effect of high mental demands at work on cognitive function in later life. However, evidence on corresponding associations in older adults at increased risk for dementia is currently lacking. This study investigates the association between mental demands at work and cognitive functioning in the population of the AgeWell.de-trial.

Methods

Cross-sectional investigation of the association between global cognitive functioning (Montreal Cognitive Assessment) and mental demands at work in older individuals at increased risk for dementia (Cardiovascular Risk Factors, Aging, and Incidence of Dementia (CAIDE)score ≥ 9; n = 941, age: 60–77 years). Occupational information was matched to Occupational Information Network (O*NET)-descriptors. Associations between cognitive function and O*NET-indices executive, verbal and novelty were investigated using generalized linear models.

Results

Higher values of index verbal (b = .69, p = .002) were associated with better cognitive function when adjusting for covariates. No association was observed for indices executive (b = .37, p = .062) and novelty (b = .45, p = .119). Higher education, younger age, and employment were linked to better cognitive function, while preexisting medical conditions did not change the associations. Higher levels of depressive symptomatology were associated with worse cognitive function.

Conclusions

Higher levels of verbal demands at work were associated with better cognitive function for older adults with increased dementia risk. This suggests an advantage for older persons in jobs with high mental demands even after retirement and despite prevalent risk factors. Longitudinal studies are warranted to confirm these results and evaluate the potential of workplaces to prevent cognitive decline through increased mental demands.

Working life job strain status and cognitive aging in Europe: A 12-year follow-up study

BACKGROUND

To examine the association of job strain with cognitive ability and the influence of life-course job strain on later life cognitive decline.

METHODS

Data were derived from six waves of the Survey of Health, Aging, and Retirement in Europe. The study sample consists of 13349 participants aged 50 to 98 years at wave 2 and has been followed up for 12-years. Job strain status across working life was assessed using a short demand-control job strain model containing two core dimensions: job demands and job control collected in wave 3. Cognitive abilities concerning episodic memory was assessed by immediate recall and delayed recall tests, executive function was evaluated by verbal fluency test collected in all waves (waves 2-7) except wave 3. Mixed-effects model was used to estimate working life job strain and its cumulative effect on cognitive decline.

RESULTS

Both passive and high strain jobs were associated with lower levels of cognitive ability (episodic memory and verbal fluency) in comparison with active job. Long exposure to active- or low strain-job was associated with higher cognitive ability whereas long exposure to passive job or moderate duration of high strain job was associated with lower cognitive ability. The rate of memory decline was positively related to moderate duration of passive job and negatively related to long-term exposure to low strain job.

LIMITATIONS

Information on working conditions was based on self-reported recollections.

CONCLUSIONS

Working life variation in job strain status and their duration may explain individual differences in cognitive ability in later life.

Organizational Justice and Cognitive Failures in Japanese Employees: A Cross-Sectional Study

OBJECTIVE

We examined the association of organizational justice (ie, procedural justice and interactional justice) with cognitive failures, and the mediation effect of psychological distress on this association in Japanese employees.

METHODS

A total of 189 men and 35 women from two sites of a manufacturing company in Japan were surveyed using a self-administered web-based questionnaire. A multiple mediation analysis was conducted.

RESULTS

A significant negative total effect of procedural justice on cognitive failures was observed (c = -0.180 [95% confidence interval: -0.315 to -0.044]). Furthermore, the mediation effect of psychological distress was significant (c-c' = -0.213 [95% confidence interval: -0.323 to -0.115]). Similar patterns were observed for interactional justice.

CONCLUSIONS

Employees may be more likely to experience cognitive failures in daily activities in work settings where organizational justice is lower, which seems to be explained by psychological distress.

Job Strain and Trajectories of Cognitive Change Before and After Retirement

OBJECTIVES

We examined associations between job strain and trajectories of change in cognitive functioning (general cognitive ability plus verbal, spatial, memory, and speed domains) before and after retirement.

METHODS

Data on indicators of job strain, retirement age, and cognitive factors were available from 307 members of the Swedish Adoption/Twin Study of Aging. Participants were followed up for up to 27 years (mean = 15.4, SD = 8.5).

RESULTS

In growth curve analyses controlling for age, sex, education, depressive symptoms, cardiovascular health, and twinness, greater job strain was associated with general cognitive ability (estimate = -1.33, p = .002), worse memory (estimate = -1.22, p = .007), speed (estimate = -1.11, p = .012), and spatial ability (estimate = -0.96, p = .043) at retirement. Greater job strain was also associated with less improvement in general cognitive ability before retirement and a somewhat slower decline after retirement. The sex-stratified analyses showed that the smaller gains of general cognitive ability before retirement (estimate = -1.09, p = .005) were only observed in women. Domain-specific analyses revealed that greater job strain was associated with less improvement in spatial (estimate = -1.35, p = .010) and verbal (estimate = -0.64, p = .047) ability before retirement in women and a slower decline in memory after retirement in women (estimate = 0.85, p = .008) and men (estimate = 1.12, p = .013). Neither preretirement nor postretirement speed was affected significantly by job strain.

DISCUSSION

Greater job strain may have a negative influence on overall cognitive functioning prior to and at retirement, while interrupting exposure to job strain (postretirement) may slow the rate of cognitive aging. Reducing the level of stress at work should be seen as a potential target for intervention to improve cognitive aging outcomes.

Cumulative exposure to psychosocial stressors at work and global cognitive function: the PROspective Quebec Study on Work and Health

OBJECTIVES

Psychosocial stressors at work have been proposed as modifiable risk factors for mild cognitive impairment (MCI). This study aimed to evaluate the effect of cumulative exposure to psychosocial stressors at work on cognitive function.

METHODS

This study was conducted among 9188 white-collar workers recruited in 1991-1993 (T1), with follow-ups 8 (T2) and 24 years later (T3). After excluding death, losses to follow-up and retirees at T2, 5728 participants were included. Psychosocial stressors at work were measured according to the Karasek's questionnaire. Global cognitive function was measured with the Montreal Cognitive Assessment. Cumulative exposures to low psychological demand, low job control, passive job and high strain job were evaluated using marginal structural models including multiple imputation and inverse probability of censoring weighting.

RESULTS

In men, cumulative exposures (T1 and T2) to low psychological demand, low job control or passive job were associated with higher prevalences of more severe presentation of MCI (MSMCI) at T3 (Prevalence ratios (PRs) and 95% CIs of 1.50 (1.16 to 1.94); 1.38 (1.07 to 1.79) and 1.55 (1.20 to 2.00), respectively), but not with milder presentation of MCI. In women, only exposure to low psychological demand or passive job at T2 was associated with higher prevalences of MSMCI at T3 (PRs and 95% CI of 1.39 (0.97 to 1.99) and 1.29 (0.94 to 1.76), respectively).

CONCLUSIONS

These results support the deleterious effect of a low stimulating job on cognitive function and the cognitive reserve theory. Psychosocial stressors at work could be part of the effort for the primary prevention of cognitive decline.

Social hallmarks of aging: Suggestions for geroscience research

This paper focuses on the social hallmarks of aging including low lifetime socioeconomic status, adversity in childhood and adulthood, being a member of a minority group, adverse health behaviors, and adverse psychological states. The "Social Hallmarks of Aging" are analogous to the "Geroscience Hallmarks of Aging" in reflecting a set of underlying and interrelated social causes of multiple age-related health outcomes. The paper presents empirical work incorporating the social hallmarks of aging with indicators of multiple biological hallmarks of aging as well as downstream biology in explaining a range of health outcomes. Results show the relative strength of the associations of social and biological measures with important health outcomes. Social factors are strongly related to physical and cognitive functioning and multimorbidity in this older population; this remains true when the significant number of biological measures are controlled. These results can be interpreted to mean that a significant amount of the social variance in age-related health outcomes is not explained by these measures of biology. Indicators of the geroscience hallmarks of aging only relate modestly to the variability in human health outcomes. Attention to the social hallmarks related to human aging can usefully be incorporated into work on the biological hallmarks of aging to make greater progress in understanding human aging.

Work-related stress and cognitive performance among middle-aged adults: The Brazilian Longitudinal Study of Adult Health (ELSA-Brasil)

Assessing risk factors exposure, such as stress in the workplace during adulthood, may contribute to detecting early signs of cognitive impairment in order to implement effective actions to improve brain health and consequently to decrease cognitive disorders later in life. In this cross-sectional study, we aimed to investigate whether work-related stress is associated with low cognitive performance in middle-aged adults from the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil) and whether social support mediates this relationship. Work-related stress was evaluated in 9,969 workers using the Demand-Control-Support Questionnaire. Cognitive function was assessed using the verbal fluency, trail-making version B, and delayed recall word tests. Work-related stress was associated with lower performance on the delayed recall, verbal fluency, and executive function tests in middle-aged adults. Social support may mediate the association between work demands and cognitive performance. These findings support that work-related stress is associated with cognitive performance during adulthood.

Job strain and cognitive change: the Baltimore Epidemiologic Catchment Area follow-up study

OBJECTIVES

To investigate the association between job strain and subsequent cognitive change over approximately 11 years, using data from the population-based Baltimore Epidemiologic Catchment Area follow-up study.

METHODS

The sample ranged from 555 to 563 participants, depending on the outcome, who reported psychosocial characteristics corresponding to the full-time job they held at baseline (1993-1996). Overall cognitive performance was measured by the Mini-Mental State Examination (MMSE), and verbal memory was measured by the ImmediateWord Recall Task and Delayed Word Recall Task at baseline and follow-up (2004-2005). Multiple linear regression was used to examine the association between job strain and cognitive change, and inverse probability weighting was used to account for differential attrition.

RESULTS

Participants with high job demands (psychological or physical demands) and/or low job control had greater decrease in the MMSE and memory scores than those with low job demands and high job control. After adjustment for baseline outcome scores, age and sex, the greatest decrease was observed in participants with high job demands and low job control (MMSE: -0.24, 95% CI -0.36 to -0.11; verbal memory scores: -0.26, 95% CI -0.44 to -0.07). The differences were partially explained by sociodemographic characteristics, occupational prestige and health factors.

CONCLUSIONS

Findings from this prospective study suggest that job strain is associated with and may be a potential modifiable risk factor for adverse cognitive outcomes.

Socioeconomic status, gender and dementia: The influence of work environment exposures and their interactions with APOE ɛ4

It is a well-established fact that unfavourable social and economic conditions have a negative impact on health and longevity. Recent findings suggest that this is also true of age-related dementias. Yet most common indicators of socioeconomic status (SES) say very little about the actual mechanisms at play in disease development. The present paper explores five work exposure characteristics, all of which have a clear social gradient, that could potentially shed further light on the relationship between SES and dementia. Specifically, it investigates whether these exposures could moderate the impact of a well-known genetic risk factor: the APOE ɛ4 allele. The empirical analyses are based on data from a Swedish population study (n = 1019). Main occupation was linked to The Job Exposure Matrix to estimate the individuals’ exposure to the following work environment factors: work control, support, psychological demands, physical demands and job hazards. All analyses were conducted using binary logistic regression and focused specifically on gene-work exposure interactions. A significant main effect of work control on dementia risk was detected for males (OR = 0.68; p< 0.05), but not for females. However, control was found to significantly moderate the effect of APOE ɛ4 in both genders, albeit in different ways. These findings do not only underscore the importance of considering interactions between social and genetic risk factors to better understanding multifactorial diseases such as dementia. They also propose that gender- and class-based inequities interact, and hence must be considered simultaneously, also in relation to this particular disease.

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There are steep social gradients in exposure to various work environment conditions.

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Work control alters the effect of APOE ɛ4 in both genders, albeit in different ways.

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High work control protects male, but not female, APOE ɛ4-carriers.

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‘Male’ high control jobs differ greatly from ‘female’ high control jobs.

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Gender- and class-based inequities interact also in the development of dementia.

Do Effort and Reward at Work Predict Changes in Cognitive Function? First Longitudinal Results from the Representative German Socio-Economic Panel

It has been suggested that work characteristics, such as mental demands, job control, and occupational complexity, are prospectively related to cognitive function. However, current evidence on links between psychosocial working conditions and cognitive change over time is inconsistent. In this study, we applied the effort–reward imbalance model that allows to build on previous research on mental demands and to introduce reward-based learning as a principle with beneficial effect on cognitive function. We aimed to investigate whether high effort, high reward, and low over-commitment in 2006 were associated with positive changes in cognitive function in terms of perceptual speed and word fluency (2006–2012), and whether the co-manifestation of high effort and high reward would yield the strongest association. To this end, we used data on 1031 employees who participated in a large and representative study. Multivariate linear regression analyses supported our main hypotheses (separate and combined effects of effort and reward), particularly on changes in perceptual speed, whereas the effects of over-commitment did not reach the level of statistical significance. Our findings extend available knowledge by examining the course of cognitive function over time. If corroborated by further evidence, organization-based measures in the workplace can enrich efforts towards preventing cognitive decline in ageing workforces.

Midlife Work-Related Stress Increases Dementia Risk in Later Life: The CAIDE 30-Year Study

Objective

To investigate the associations between midlife work-related stress and mild cognitive impairment (MCI), dementia, and Alzheimer's disease later in life, in a large representative population.

Method

Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study participants were randomly selected from independent population-based surveys (mean age 50 years). A random sample of 2,000 individuals was invited for two reexaminations including cognitive tests (at mean age 71 and mean age 78), and 1,511 subjects participated in at least one reexamination (mean follow-up 28.5 years). Work-related stress was measured using two questions on work demands that were administered in midlife. Analyses adjusted for important confounders.

Results

Higher levels of midlife work-related stress were associated with higher risk of MCI (odds ratio [OR], 1.38; 95% confidence interval [CI], 1.08-1.76), dementia (OR, 1.53; CI, 1.13-2.07), and Alzheimer's disease (OR, 1.55; CI, 1.19-2.36) at the first follow-up among the CAIDE participants. Results remained significant after adjusting for several possible confounders. Work-related stress was not associated with MCI and dementia during the extended follow-up.

Discussion

Midlife work-related stress increases the risk for MCI, dementia, and Alzheimer's disease in later life. The association was not seen after the extended follow-up possibly reflecting selective survival/participation, heterogeneity in dementia among the oldest old, and a critical time window for the effects of midlife stress.

Midlife work-related stress is associated with late-life cognition

To investigate the associations between midlife work-related stress and late-life cognition in individuals without dementia from the general population. The Cardiovascular Risk Factors, Aging and Dementia (CAIDE) study population (n = 2000) was randomly selected from independent Finnish population-based surveys (baseline mean age 50 years). Participants underwent two re-examinations in late life (mean age 71 and 78 years, respectively). 1511 subjects participated in at least one re-examination (mean total follow-up 25 years). Work-related stress was measured using two questions on work demands administered in midlife. Multiple cognitive domains were assessed. Analyses were adjusted for several potential confounders. Higher levels of midlife work-related stress were associated with poorer performance on global cognition [β-coefficient, -0.02; 95% confidence interval (CI), -0.05 to -0.00], and processing speed [β -0.03, CI -0.05 to -0.01]. Results remained significant after adjusting for potential confounders. Work-related stress was not significantly associated with episodic memory, executive functioning, verbal fluency or manual dexterity. This study shows that global cognition and processing speed may be particularly susceptible to the effects of midlife work-related stress.

Can psychosocial work conditions protect against age-related cognitive decline? Results from a systematic review

According to the use it or lose it hypothesis, intellectually stimulating activities postpone age-related cognitive decline. A previous systematic review concluded that a high level of mental work demands and job control protected against cognitive decline. However, it did not distinguish between outcomes that were measured as cognitive function at one point in time or as cognitive decline. Our study aimed to systematically review which psychosocial working conditions were prospectively associated with high levels of cognitive function and/or changes in cognitive function over time. Articles were identified by a systematic literature search (MEDLINE, Web of Science (WOS), PsycNET, Occupational Safety and Health (OSH)). We included only studies with longitudinal designs examining the impact of psychosocial work conditions on outcomes defined as cognitive function or changes in cognitive function. Two independent reviewers compared title-abstract screenings, full-text screenings and quality assessment ratings. Eleven studies were included in the final synthesis and showed that high levels of mental work demands, occupational complexity or job control at one point in time were prospectively associated with higher levels of cognitive function in midlife or late life. However, the evidence to clarify whether these psychosocial factors also affected cognitive decline was insufficient, conflicting or weak. It remains speculative whether job control, job demands or occupational complexity can protect against cognitive decline. Future studies using methodological advancements can reveal whether workers gain more cognitive reserve in midlife and late life than the available evidence currently suggests. The public health implications of a previous review should thereby be redefined accordingly.

Domains of cognitive function in early old age: which ones are predicted by pre-retirement psychosocial work characteristics?

BACKGROUND

Psychosocial work characteristics may predict cognitive functioning after retirement. However, little research has explored specific cognitive domains associated with psychosocial work environments. Our study tested whether exposure to job demands, job control and their combination during working life predicted post-retirement performance on eight cognitive tests.

METHODS

We used data from French GAZEL cohort members who had undergone post-retirement cognitive testing (n=2149). Psychosocial job characteristics were measured on average for 4 years before retirement using Karasek's Job Content Questionnaire (job demands, job control and demand-control combinations). We tested associations between these exposures and post-retirement performance on tests for executive function, visual-motor speed, psychomotor speed, verbal memory, and verbal fluency using ordinary least squares regression.

RESULTS

Low job control during working life was negatively associated with executive function, psychomotor speed, phonemic fluency and semantic fluency after retirement (p's<0.05), even after adjustment for demographics, socioeconomic status, health and social behaviours and vascular risk factors. Both passive (low-demand, low-control) and high-strain (high-demand, low-control) jobs were associated with lower scores on phonemic and semantic fluency when compared to low-strain (low-demand, high-control) jobs.

CONCLUSIONS

Low job control, in combination with both high and low-job demands, is associated with post-retirement deficits in some, but not all, cognitive domains. In addition to work stress, associations between passive work and subsequent cognitive function may implicate lack of cognitive engagement at work as a risk factor for future cognitive difficulties.

Job strain and trajectories of change in episodic memory before and after retirement: results from the Health and Retirement Study

BACKGROUND

We examined indicators of job strain in relation to level and change in episodic memory in the years leading up to as well as following retirement.

METHODS

Our analyses centre on 3779 individuals from the nationally representative Health and Retirement Study (baseline age 57.3 years) who reported gainful employment in an occupation for 10+ years prior to retirement, and who were assessed for episodic memory performance over up to 20 years (median 8 waves over 16 years). We used ratings from the Occupational Information Network (O*Net) to score occupations for job control and job demands, and to measure job strain (job demands/job control).

RESULTS

Controlling for sociodemographic characteristics, depressive symptoms, and cardiovascular disease, less job control and greater job strain were not significantly associated with change in episodic memory in the period leading up to retirement, but were associated with significantly poorer episodic memory at retirement and an accelerated rate of decline in episodic memory following retirement. The results did not vary for men and women or by self-employment status.

CONCLUSIONS

Job strain expressed mainly as low job control is linked to poorer episodic memory at retirement and more decline after retirement. Job characteristics appear to have implications for cognitive ageing independent of relevant confounds.

Association between exposure to work stressors and cognitive performance

OBJECTIVE

To examine the association between work stress and cognitive performance.

METHODS

Cognitive performance of a total of 99 women (mean age = 47.3 years) working in hospital wards at either the top or bottom quartiles of job strain was assessed using validated tests that measured learning, short-term memory, and speed of memory retrieval.

RESULTS

The high job strain group (n = 43) had lower performance than the low job strain group (n = 56) in learning (P = 0.025), short-term memory (P = 0.027), and speed of memory retrieval (P = 0.003). After controlling for education level, only the difference in speed of memory retrieval remained statistically significant (P = 0.010).

CONCLUSIONS

The association found between job strain and speed of memory retrieval might be one important factor explaining the effect of stress on work performance.

Is there an association between work stress and diurnal cortisol patterns? Findings from the Whitehall II study

OBJECTIVE

The evidence on whether there is work stress related dysregulation of the hypothalamic-pituitary-adrenal axis is equivocal. This study assessed the relation between work stress and diurnal cortisol rhythm in a large-scale occupational cohort, the Whitehall II study.

METHODS

Work stress was assessed in two ways, using the job-demand-control (JDC) and the effort-reward-imbalance (ERI) models. Salivary cortisol samples were collected six times over a normal day in 2002-2004. The cortisol awakening response (CAR) and diurnal cortisol decline (slope) were calculated.

RESULTS

In this large occupational cohort (N = 2,126, mean age 57.1), modest differences in cortisol patterns were found for ERI models only, showing lower reward (β = -0.001, P-value = 0.04) and higher ERI (β = 0.002, P-value = 0.05) were related to a flatter slope in cortisol across the day. Meanwhile, moderate gender interactions were observed regarding CAR and JDC model.

CONCLUSIONS

We conclude that the associations of work stress with cortisol are modest, with associations apparent for ERI model rather than JDC model.

Psychosocial working conditions and cognitive complaints among Swedish employees

BACKGROUND

Cognitive complaints involving problems with concentration, memory, decision-making and thinking are relatively common in the work force. The sensitivity of both subjective and objective cognitive functioning to common psychiatric conditions, stress levels and to cognitive load makes it plausible that psychosocial working conditions play a role in cognitive complaints. Thus, this study aimed to test the associations between psychosocial work factors and cognitive complaints in nationally representative samples of the Swedish work force. Cross-sectional (n = 9751) and prospective (n = 3644; two time points two years apart) sequential multiple regression analyses were run, adjusting for general confounders, depressive- and sleeping problems. Additional prospective analyses were run adjusting for baseline cognitive complaints.

CROSS/SECTIONAL RESULTS

High quantitative demands, information and communication technology (ICT) demands, under qualification and conflicts were positively associated with cognitive complaints, while social support, good resources at work and over qualification were negatively associated with cognitive complaints in all models. Skill discretion and decision authority were weakly associated with cognitive complaints. Conflicts were more strongly associated with cognitive complaints in women than in men, after adjustment for general confounders.

PROSPECTIVE RESULTS

Quantitative job demands, ICT demands and under qualification were positively associated with future cognitive complaints in all models, including when adjusted for baseline cognitive complaints. Decision authority was weakly positively associated with future cognitive complaints, only after adjustment for depressive- and sleeping problems respectively. Social support was negatively associated with future cognitive complaints after adjustment for general confounders and baseline cognitive complaints. Skill discretion and resources were negatively associated with future cognitive complaints after adjustment for general confounders. The associations between quantitative demands and future cognitive complaints were stronger in women.

DISCUSSION/CONCLUSIONS

The findings indicate that psychosocial working conditions should be taken into account when considering cognitive complaints among employees.

The Road to Psychological Safety

In Part 1 of this article, the legal and scientific origins of the concept of psychological safety are examined as background to, and support for, the new Canadian National Standard on Psychological Health and Safety in the Workplace (CSA Z1003/BNQ 9700). It is shown that five factors influencing psychological safety can be identified as being common to both legal and scientific perspectives: job demands and requirements of effort, job control or influence, reward, fairness, and support. This convergence of evidence from legal and scientific perspectives creates a powerful case for the development of a national standard built around these five factors. In Part 2, it is proposed that the introduction of a national standard can be expected in the long run to have positive social benefits since the health or harm that is generated in the workplace does not remain there but migrates into families, communities, and society at large in the form of either social capital or social exhaust. Consequently, psychological safety is a concept that connects the dynamics of the workplace to the health, resilience, and well-being of society at large.

Chronic stress modulates neural and cardiovascular responses during reversal learning

Animal studies have revealed that chronic stress shifts cognitive strategies from the flexible goal-directed action to the simple and rigid habit action. In addition, stress-induced atrophy in the prefrontal cortex and dorsomedial striatum which are involved in the goal-directed action and hypertrophy of the dorsolateral striatum which is critical for the habit action were parallel with the effects of chronic stress on behaviors. The present study tested whether these previous findings in animal studies are compatible in humans by analyzing effects of chronic stress on neural and cardiovascular responses, which are likely important for performing appropriate actions. Twenty healthy men exposed to low or high chronic job stress performed a stochastic reversal learning task, which required cognitive flexibility and the goal-directed action. Regional cerebral blood flow was evaluated during the task using (15)O-water positron emission tomography, and cardiovascular parameters such as blood pressure and heart rate were also measured. During the reversal learning task, whereas participants with low chronic job stress exhibited activity in the anterior caudate, as well as orbitofrontal cortex, ventrolateral prefrontal cortex, insula, and midbrain, which might be related to the goal-directed action, participants with high chronic job stress exhibited no activity in such brain regions. Furthermore, participants with high chronic job stress exhibited less reactivity in diastolic blood pressure, which might be mediated by anterior cingulate cortical activity. These findings, in line with previous studies, suggested that chronic job stress correlates with less activity in brain regions related to the goal-directed action, and insensitive physiological responses in humans.

Indicators of job strain at midlife and cognitive functioning in advanced old age

OBJECTIVES

We used data from SWEOLD, a Swedish nationally representative study of individuals aged 77 years or older, to examine midlife indicators of job strain in relation to cognitive performance and impairment.

METHODS

In all, 827 participants completed an abridged 11-point version of the Mini-Mental State Examination in-person in 1992 and/or 2002 and had self-reported and/or occupation-based scores for job control and demands from data collected in 1968. Seventeen percent scored below the cutoff for cognitive impairment.

RESULTS

Controlling for age, sex, education, self-rated health, and year of cognitive screening, low self-reported and occupation-based job control at midlife was associated with poorer cognitive performance later (ps < .001). For the occupation-based measure, low job control was also associated with greater likelihood of impairment, whereas having an active job (high job control/high job demands) was associated with better cognitive performance and lower likelihood of impairment (ps < .01). Childhood environment, midlife depressive symptoms, and social activity had limited influence, whereas the influence of both adulthood socioeconomic position and work complexity on these results was more pronounced.

DISCUSSION

Job control at midlife, by itself and in combination with job demands, may influence cognitive functioning later above and beyond demographic variables and other occupational characteristics.

Cognitive functioning in relation to burnout symptoms and social and occupational functioning in a population-based sample of young adults

BACKGROUND

There may be an association between cognitive functioning and burnout, but this has previously been investigated in only few studies, all using clinical samples.

AIMS

This study aimed at examining the relationship of cognitive functioning with burnout symptoms and social and occupational functioning in a population-based sample of young adults.

METHODS

Neuropsychological tests assessing verbal and visual short-term memory, verbal long-term memory, general intelligence, attention, psychomotor processing speed and executive functioning were administered to a population-based sample of working young adults aged 22-35 years (n=225). Burnout was measured with the Maslach Burnout Survey-General Survey (MBI-GS) and social and occupational functioning with examiner-rated Social and Occupational Functioning Assessment Scale (SOFAS).

RESULTS

Higher scores in the MBI-GS related to better performance in tests of verbal working memory and general intelligence. Lower SOFAS associated with poorer performance in tests assessing verbal attention, memory and learning.

CONCLUSIONS

In a representative population sample of young adults, self-reported symptoms of burnout are not associated with difficulties in cognitive functioning. However, examiner-rated lower social and occupational functioning is related to problems in verbal attention, memory and learning, suggesting the importance of evaluating and enhancing cognitive functioning among those with difficulties in social and occupational functioning.

Organisational justice and cognitive function in middle-aged employees: the Whitehall II study

BACKGROUND

Little is known about the role that work-related factors play in the decline of cognitive function. This study examined the association between perceived organisational justice and cognitive function among middle-aged men and women.

METHODS

Perceived organisational justice was measured at phases 1 (1985-8) and 2 (1989-90) of the Whitehall II study when the participants were 35-55 years old. Assessment of cognitive function at the screening clinic at phases 5 (1997-9) and 7 (2003-4) included the following tests in the screening clinic: memory, inductive reasoning (Alice Heim 4), vocabulary (Mill Hill), and verbal fluency (phonemic and semantic). Mean exposure to lower organisational justice at phases 1 and 2 in relation to cognitive function at phases 5 and 7 were analysed using linear regression analyses. The final sample included 4531 men and women.

RESULTS

Lower mean levels of justice at phases 1 and 2 were associated with worse cognitive function in terms of memory, inductive reasoning, vocabulary and verbal fluency at both phases 5 and 7. These associations were independent of covariates, such as age, occupational grade, behavioural risks, depression, hypertension and job strain.

CONCLUSIONS

This study suggests an association between perceived organisational justice and cognitive function. Further studies are needed to examine whether interventions designed to improve organisational justice would affect employees' cognition function favourably.

Psychosocial stress at work doubles the risk of type 2 diabetes in middle-aged women: evidence from the Whitehall II study

OBJECTIVE

To investigate the effect of psychosocial stress at work on risk of type 2 diabetes, adjusting for conventional risk factors, among a sample of British, white-collar, middle-aged men and women.

RESEARCH DESIGN AND METHODS

This was a prospective analysis (1991-2004) from the Whitehall II cohort study. The current sample consists of 5,895 Caucasian middle-aged civil servants free from diabetes at baseline. Type 2 diabetes was ascertained by an oral glucose tolerance test supplemented by self-reports at baseline and four consecutive waves of data collection including two screening phases. The job strain and iso-strain models were used to assess psychosocial work stress.

RESULTS

Iso-strain in the workplace was associated with a twofold higher risk of type 2 diabetes in age-adjusted analysis in women but not in men (hazard ratio 1.94 [95% CI 1.17-3.21). This effect remained robust to adjustment for socioeconomic position and outside work stressors and was only attenuated by 20% after adjustment for health behaviors, obesity, and other type 2 diabetes risk factors.

CONCLUSIONS

Psychosocial work stress was an independent predictor of type 2 diabetes among women after a 15-year follow-up. This association was not explained by potential confounding and mediating factors. More evidence from prospective studies using the same work stress models is needed to support the current findings and provide further information on sex differences.