Cardiovascular diseases in Quebec health administrative databases: missing diagnoses and underestimation of the number of cases in a 28-year prospective cohort. / Maladies cardiovasculaires dans les fichiers médico-administratifs québécois : diagnostics manquants et sous-estimation du nombre de cas dans une cohorte prospective de 28 ans.

INTRODUCTION: Cardiovascular disease (CVD) surveillance in Quebec and the rest of Canada is carried out using health administrative databases, which in Quebec includes the physician claims database. The presence of billing claims without diagnoses can lead to the number of CVD cases being underestimated. The purpose of this study is to estimate the proportion of CVD diagnoses and CVD cases that may be missing from these databases. METHODS: The study was conducted using a prospective cohort of 8781 participants living in the Québec City area. Access to health administrative databases was granted for the entire 28-year follow-up period. First, we performed frequency analyses to estimate the proportion of missing CVD diagnoses. Then we used validated algorithms to identify CVD cases and estimate the proportion of CVD cases that were potentially not captured over the 28-year period. RESULTS: About one-fifth (22.1%) of the diagnoses in the physician claims database were missing. The proportion of missing CVD cases was estimated at 12.7% for 1991-2018, although this varied with the period covered (1991-1996: 15.5%; 1997-2013: 10.7%; and 2014-2018: 16.3%). CONCLUSION: Approximatively 1 in 10 CVD cases are not identified due to a missing diagnosis. This underestimation of CVD cases is a potential limitation that should be considered when using Quebec health administrative databases to identify CVD cases for surveillance work and epidemiological studies.

Direct medical costs of cardiovascular diseases: Do cost components vary according to sex and age?

BACKGROUND: The aim was to estimate direct medical costs of men and women patients by age group related to cardiovascular diseases (coronary heart disease, strokes) in the province of Quebec, Canada from the economic perspective of the healthcare public system, encompassing five cost components: physician fees, hospitalization (hospital stay, intensive care stay), emergency visits and medication costs. METHODS: This matched case-control study involved secondary data from a longitudinal cohort study (1997-2018) of 4584 white-collar workers. Participants were followed for a four-year period. We used an incremental cost method of difference-in-difference. Descriptive analyses using frequency counts, arithmetic means, standardized differences, chi-squared tests, and Student's T-tests were performed. Direct medical costs were estimated using mean and 95% bootstrap confidence interval. RESULTS: Direct medical costs per case were CAD $4970 [4344, 5595] for all in the first year after the event. For men patients, direct medical costs were $5351 [4649, 6053] and $4234 [2880, 5588] for women in the first year after the event, $221 [-229, 671] for men and $226 [-727, 1179] for women in the second year, and $11 [-356, 377] for men and $-24 [-612, 564] for women in the third year. This decrease was observed for both men and women, with higher costs for men. Within the first year, physician fees dominated CVD-associated costs among both men and women cases younger than 65. However, hospital stay represented the costliest component among cases aged 65 and older, incurring higher costs in women compared to men. In the subsequent years, the distribution of costs showed variations according to sex and age, with either medication costs or physician fees being the predominant components, depending on the specific subgroups. CONCLUSIONS: CVD-associated direct medical costs varied by components, sex, age, and follow-up years. Patients with CVD incurred more than twice the medical costs as compared to patients without CVD of same age and sex.

Effort-reward imbalance at work assessed at midlife and prediabetes prevalence assessed 18 years later in a prospective cohort of white-collar workers.

OBJECTIVES: Evidence suggests that workers exposed to psychosocial stressors at work from the effort-reward imbalance (ERI) model are at increased risk for type 2 diabetes mellitus (T2DM). However, evidence about the effect of ERI on prediabetes is scarce. This study aimed to examine the association between effort-reward imbalance at work, glycated hemoglobin level and the prevalence of prediabetes in women and men from a prospective cohort study. METHODS: This study was conducted among 1354 white-collar workers followed for an average of 18 years. Effort-reward imbalance at work was measured in 1999 to 2001 using a validated instrument. Glycated hemoglobin was assessed at follow-up (2015 to 2018). Differences in mean glycated hemoglobin levels were estimated with linear models. Prediabetes prevalence ratios (PRs) were computed using robust Poisson regression models. RESULTS: In women, those exposed to effort-reward imbalance at work at baseline had a higher prevalence of prediabetes (PR = 1.60, 95% confidence interval: 1.02-2.49) at follow-up following adjustment for sociodemographic, lifestyle-related, clinical, and other occupational risk factors. There was no difference in mean glycated hemoglobin levels. CONCLUSION: Among women, effort-reward imbalance at work at midlife was associated with the prevalence of prediabetes, at older age. Preventive workplace interventions aiming to reduce the prevalence of effort-reward imbalance at work may be effective to reduce the prevalence of prediabetes among women.

Psychosocial Stressors at Work and Atrial Fibrillation Incidence: An 18-Year Prospective Study.

BACKGROUND: Psychosocial stressors at work, defined by the job strain and effort-reward imbalance at work (ERI) models, were shown to increase coronary heart disease risk. No previous study has examined the adverse effect of psychosocial stressors at work from both models on atrial fibrillation (AF) incidence. The objective of this study was to examine the separate and combined effect of psychosocial stressors at work from the job strain and ERI models on AF incidence in a prospective cohort study. METHODS AND RESULTS: A total of 5926 white-collar workers (3021 women and 2905 men) free of cardiovascular disease at baseline were followed for an average of 18 years. Job strain (high psychological demands combined with low decision latitude) and ERI were assessed using validated instruments. AF events were identified in medical databases with universal coverage. Hazard ratios (HRs) with 95% CIs were estimated using Cox regression models, controlling for socioeconomic characteristics and lifestyle-related and clinical risk factors. A total of 186 AF incident events were identified over 18 years. Workers exposed to job strain (HR, 1.83 [95% CI, 1.14-2.92]) and ERI (HR, 1.44 [95% CI, 1.05-1.98]) had a higher risk of AF in fully adjusted models. Combined exposure to job strain and ERI was associated with a 2-fold AF risk increase (HR, 1.97 [95% CI, 1.26-3.07]). CONCLUSIONS: Psychosocial stressors at work from the job strain and ERI models are associated with an increased risk of AF, separately and in combination. Workplace prevention strategies targeting these psychosocial stressors at work may be effective to reduce the burden associated with AF.

Socioeconomic inequalities, psychosocial stressors at work and physician-diagnosed depression: Time-to-event mediation analysis in the presence of time-varying confounders.

OBJECTIVES: There is evidence that both low socioeconomic status (SES) and psychosocial stressors at work (PSW) increase risk of depression, but prospective studies on the contribution of PSW to the socioeconomic gradient of depression are still limited. METHODS: Using a prospective cohort of Quebec white-collar workers (n = 9188 participants, 50% women), we estimated randomized interventional analogues of the natural direct effect of SES indicators at baseline (education level, household income, occupation type and a combined measure) and of their natural indirect effects mediated through PSW (job strain and effort-reward imbalance (ERI) measured at the follow-up in 1999-2001) on incident physician-diagnosed depression. RESULTS: During 3 years of follow-up, we identified 469 new cases (women: 33.1 per 1000 person-years; men: 16.8). Mainly in men, low SES was a risk factor for depression [education: hazard ratio 1.72 (1.08-2.73); family income: 1.67 (1.04-2.67); occupational type: 2.13 (1.08-4.19)]. In the entire population, exposure to psychosocial stressors at work was associated with increased risk of depression [job strain: 1.42 (1.14-1.78); effort-reward imbalance (ERI) 1.73 (1.41-2.12)]. The estimated indirect effects of socioeconomic indicators on depression mediated through job strain ranged from 1.01 (0.99-1.03) to 1.04 (0.98-1.10), 4-15% of total effects, and for low reward from 1.02 (1.00-1.03) to 1.06 (1.01-1.11), 10-15% of total effects. DISCUSSION: Our study suggests that PSW only slightly mediate the socioeconomic gradient of depression, but that socioeconomic inequalities, especially among men, and PSW both increase the incidence of depression.

Psychosocial Stressors at Work and Coronary Heart Disease Risk in Men and Women: 18-Year Prospective Cohort Study of Combined Exposures.

BACKGROUND: Psychosocial stressors at work, like job strain and effort-reward imbalance (ERI), can increase coronary heart disease (CHD) risk. ERI indicates an imbalance between the effort and received rewards. Evidence about the adverse effect of combined exposure to these work stressors on CHD risk is scarce. This study examines the separate and combined effect of job strain and ERI exposure on CHD incidence in a prospective cohort of white-collar workers in Quebec, Canada. METHODS: Six thousand four hundred sixty-five white-collar workers without cardiovascular disease (mean age, 45.3±6.7) were followed for 18 years (from 2000 to 2018). Job strain and ERI were measured with validated questionnaires. CHD events were retrieved from medico-administrative databases using validated algorithms. Marginal Cox models were used to calculate hazard ratios (HR) stratified by sex. Multiple imputation and inverse probability weights were applied to minimize potential threats to internal validity. RESULTS: Among 3118 men, 571 had a first CHD event. Exposure to either job strain or ERI was associated with an adjusted 49% CHD risk increase (HR, 1.49 [95% CI, 1.07-2.09]). Combined exposure to job strain and ERI was associated with an adjusted 103% CHD risk increase (HR, 2.03 [95% CI, 1.38-2.97]). Exclusion of early CHD cases and censoring at retirement did not alter these associations. Among 3347 women, 265 had a first CHD event. Findings were inconclusive (passive job HR, 1.24 [95% CI, 0.80-1.91]; active job HR, 1.16 [95% CI, 0.70-1.94]; job strain HR, 1.08 [95% CI, 0.66-1.77]; ERI HR, 1.02 [95% CI, 0.72-1.45]). CONCLUSIONS: In this prospective cohort study, men exposed to job strain or ERI, separately and in combination, were at increased risk of CHD. Early interventions on these psychosocial stressors at work in men may be effective prevention strategies to reduce CHD burden. Among women, further investigation is required.

Association between psychosocial work-related factors at midlife and arterial stiffness at older age in a prospective cohort of 1736 white-collar workers.

OBJECTIVE: Arterial stiffness and exposure to psychosocial work-related factors increase the risk of developing cardiovascular disease. However, little is known about the relationship between psychosocial work-related factors and arterial stiffness. We aimed to examine this relationship. DESIGN: Prospective cohort study. SETTING: Public organisations in Quebec City, Canada. PARTICIPANTS: The study included 1736 white-collar workers (women 52%) from 19 public organisations. PRIMARY AND SECONDARY OUTCOME MEASURES: Association between psychosocial work-related factors from the job strain and effort-reward imbalance (ERI) models assessed at study baseline (1999-2001) with validated instruments and arterial stiffness assessed using carotid-femoral pulse wave velocity at follow-up, on average 16 years later (2015-2018). Generalised estimating equations were used to estimate differences in arterial stiffness between exposed and unexposed participants. Subgroup analyses according to sex, age, blood pressure (BP), cardiovascular risk score and employment status were conducted. RESULTS: Among participants with high diastolic BP (≥90 mm Hg) at baseline, aged 47 on average, those exposed to high job strain had higher arterial stiffness (1.38 m/s (95% CI: 0.57 to 2.19)) at follow-up, 16 years later, following adjustment for a large set of potential confounders. The trend was similar in participants with high systolic BP (≥140 mm Hg) exposed to high job strain (0.84 m/s (95% CI: -0.35 to 2.03)). No association was observed for ERI in the total sample and counterintuitive associations were observed in subgroup analyses. CONCLUSIONS: Job strain may have a long-term deleterious effect on arterial stiffness in people with high BP. Interventions at midlife to reduce job strain may mitigate arterial stiffness progression.

Work-Related Psychosocial Factors and Global Cognitive Function: Are Telomere Length and Low-Grade Inflammation Potential Mediators of This Association?

The identification of modifiable factors that could maintain cognitive function is a public health priority. It is thought that some work-related psychosocial factors help developing cognitive reserve through high intellectual complexity. However, they also have well-known adverse health effects and are considered to be chronic psychosocial stressors. Indeed, these stressors could increase low-grade inflammation and promote oxidative stress associated with accelerated telomere shortening. Both low-grade inflammation and shorter telomeres have been associated with a cognitive decline. This study aimed to evaluate the total, direct, and indirect effects of work-related psychosocial factors on global cognitive function overall and by sex, through telomere length and an inflammatory index. A random sample of 2219 participants followed over 17 years was included in this study, with blood samples and data with cognitive function drawn from a longitudinal study of 9188 white-collar workers (51% female). Work-related psychosocial factors were evaluated according to the Demand-Control-Support and the Effort-Reward Imbalance (ERI) models. Global cognitive function was evaluated with the validated Montreal Cognitive Assessment (MoCA). Telomere length and inflammatory biomarkers were measured using standardised protocols. The direct and indirect effects were estimated using a novel mediation analysis method developed for multiple correlated mediators. Associations were observed between passive work or low job control, and shorter telomeres among females, and between low social support at work, ERI or iso-strain, and a higher inflammatory index among males. An association was observed with higher cognitive performance for longer telomeres, but not for the inflammatory index. Passive work overall, and low reward were associated with lower cognitive performance in males; whereas, high psychological demand in both males and females and high job strain in females were associated with a higher cognitive performance. However, none of these associations were mediated by telomere length or the inflammatory index. This study suggests that some work-related psychosocial factors could be associated with shorter telomeres and low-grade inflammation, but these associations do not explain the relationship between work-related psychosocial factors and global cognitive function. A better understanding of the biological pathways, by which these factors affect cognitive function, could guide future preventive strategies to maintain cognitive function and promote healthy aging.

Issue with Evaluating Costs Over Time in a Context of Medical Guideline Changes: An Example in Myocardial Infarction Care Based on a Longitudinal Study from 1997 to 2018.

BACKGROUND: Cost studies appear sporadically in the scientific literature and are rarely revised unless drastic technological advancements occur. However, health technologies and medical guidelines evolve over time. It is unclear if these changes render obsolete prior estimates. We examined this issue in a cost study in the context of patients' first myocardial infarction (MI), a clinical area prone to such continuous evolution in care. METHODS: We conducted a longitudinal cost analysis based on a Quebec cohort. Quebec health administrative databases were used to identify incident MI cases using diagnostic codes from the international classification of diseases (ICD-9 and ICD-10). Physician fees and hospitalization costs (ie, costs incurred by the hospital center) were derived from administrative databases and a university hospital's finance department. All costs were converted to 2019 Canadian dollars. Nonparametric bootstraps were used to estimate 95% confidence intervals (CI) of the average costs of an episode of care. Generalized linear regressions were used to examine temporal trends of cost. RESULTS: Our study sample consists of 261 patients hospitalized for a first MI. The average total cost for this first event was estimated at $5782 (95% CI: $5293 - $6373). Though total costs remained stable over time, physician fees increased by 123% ($1240 vs $2761) whereas total hospital length of stay dropped by 17% (6.6 vs 5.5 days) over the 21-year period. CONCLUSION: Patients' first MI hospitalization impose an economic burden on the healthcare system. Though overall costs remained stable, our results suggest that some cost components varied over time.

Long working hours associated with elevated ambulatory blood pressure among female and male white-collar workers over a 2.5-year follow-up.

Population-based strategies targeting modifiable risk factors are needed to improve the prevention of hypertension. Long working hours have been linked to high blood pressure (BP), but more longitudinal research is required. The objective of this study was to examine the effect of long working hours (≥41 h/week) on ambulatory BP mean over a 2.5-year follow-up. The effect modification of family responsibilities was also investigated. A repeated longitudinal design was used. Data collection was performed at three-time points over a 2.5-year follow-up among over 2000 white-collar workers. Working hours were self-reported assessed by questionnaire. BP was measured using Spacelabs 90207. The outcomes were systolic and diastolic BP mean. Cross-lagged GEE linear regressions were used to examine whether working hours were associated with BP means at the next measurement time. Women working long hours had a higher diastolic BP mean at follow-up compared to women working regular hours (+1.8 mm Hg (95% CI: 0.5-3.1)). In men, those working long hours had both higher systolic and diastolic BP means increases (systolic: +2.5 mm Hg (95% CI: 0.5-4.4)) and diastolic: +2.3 mm Hg (95% CI: 1.0-3.7)). This association was greater among workers having high family responsibilities. This longitudinal study showed that women and men working long hours had higher BP means when compared those working 35-40 h per week. These findings suggest that strategies that promote work weeks not exceeding 40 h might contribute to the primary prevention of hypertension, especially for workers with high family responsibilities.

Job strain and effort-reward imbalance as risk factors for type 2 diabetes mellitus: A systematic review and meta-analysis of prospective studies.

OBJECTIVES: This systematic review and meta-analysis aimed to synthesize the available data on prospective associations between work-related stressors and the risk of type 2 diabetes mellitus (T2DM) among adult workers, according to the demand-control-support (DCS) and the effort-reward imbalance (ERI) models. METHOD: We searched for prospective studies in PubMed, EMBASE, Web of Science, Scopus, CINHAL and PsychInfo. After screening and extraction, quality of evidence was assessed using the ROBINS-I tool adapted for observational studies. The effect estimates extracted for each cohort were synthesized using random effect models. RESULTS: We included 18 studies (reporting data on 25 cohorts) in meta-analyses for job strain, job demands, job control, social support at work and ERI. Workers exposed to job strain had a higher risk of developing T2DM when compared to unexposed workers [pooled rate ratio (RR) 1.16, 95% confidence interval (CI) 1.07-1.26]. This association was robust in several supplementary analyses. For exposed women relative to unexposed women, the RR was 1.35 (95% CI 1.12-1.64). The RR of workers exposed to ERI was 1.24 (95% CI 1.08-1.42) compared to unexposed workers. CONCLUSIONS: This is the first meta-analysis to find an effect of ERI on the onset of T2DM incidence. It also confirms that job strain increases the incidence of T2DM, especially among women.

Low Social Support at Work and Ambulatory Blood Pressure in a Repeated Cross-sectional Study of White-Collar Workers.

OBJECTIVES: Previous studies on the effect of low social support at work on blood pressure showed mixed results. Few previous studies have used ambulatory blood pressure and examined whether the effect of low social support at work vary among men and women. The aim of this study was to examine the association between low social support at work, ambulatory blood pressure means and hypertension prevalence, in a sample of white-collar workers men and women. METHODS: A repeated cross-sectional design was used. Data were collected three times during a 5-year period, among 3919 white-collar women and men. At each time, coworker and supervisor social support at work were measured using validated scales. Ambulatory blood pressure was measured every 15 min during a working day. General estimating equations were used. RESULTS: In adjusted models, women exposed to low coworker (+0.6 mmHg) and low supervisor social support at work (+0.7 mmHg) had slightly higher diastolic blood pressure means when compared to unexposed women. In men, those with low coworker social support at work had higher diastolic (+0.7 mmHg) blood pressure while those with low supervisor social support had a higher prevalence of hypertension (prevalence ratio = 1.14, 95% CI: 1.04-1.24). CONCLUSIONS: Men with low supervisor social support at work had a higher prevalence of hypertension. Low social support at work was associated with modest increases in diastolic blood pressure among men and women. Workplace prevention strategies aiming to increase social support at work could lead to beneficial effects on worker's cardiovascular health.

Validation of case definitions of depression derived from administrative data against the CIDI-SF as reference standard: results from the PROspective Québec (PROQ) study.

BACKGROUND: Administrative data have several advantages over questionnaire and interview data to identify cases of depression: they are usually inexpensive, available for a long period of time and are less subject to recall bias and differential classification errors. However, the validity of administrative data in the correct identification of depression has not yet been studied in general populations. The present study aimed to 1) evaluate the sensitivity and specificity of administrative cases of depression using the validated Composite International Diagnostic Interview - Short Form (CIDI-SF) as reference standard and 2) compare the known-groups validity between administrative and CIDI-SF cases of depression. METHODS: The 5487 participants seen at the last wave (2015-2018) of the PROQ cohort had CIDI-SF questionnaire data linked to hospitalization and medical reimbursement data provided by the provincial universal healthcare provider and coded using the International Classification of Disease. We analyzed the sensitivity and specificity of several case definitions of depression from this administrative data. Their association with known predictors of depression was estimated using robust Poisson regression models. RESULTS: Administrative cases of depression showed high specificity (≥ 96%), low sensitivity (19-32%), and rather low agreement (Cohen's kappa of 0.21-0.25) compared with the CIDI-SF. These results were consistent over strata of sex, age and education level and with varying case definitions. In known-groups analysis, the administrative cases of depression were comparable to that of CIDI-SF cases (RR for sex: 1.80 vs 2.03 respectively, age: 1.53 vs 1.40, education: 1.52 vs 1.28, psychological distress: 2.21 vs 2.65). CONCLUSION: The results obtained in this large sample of a general population suggest that the dimensions of depression captured by administrative data and by the CIDI-SF are partially distinct. However, their known-groups validity in relation to risk factors for depression was similar to that of CIDI-SF cases. We suggest that neither of these data sources is superior to the other in the context of large epidemiological studies aiming to identify and quantify risk factors for depression.

Psychosocial stressors at work and inflammatory biomarkers: PROspective Quebec Study on Work and Health.

BACKGROUND: Chronic low-grade inflammation has been associated with high risk of several chronic diseases such as cardiovascular diseases, diabetes, depression, and dementia. As low-grade inflammation could be present long before the apparition of the disease, identifying modifiable risk factors could allow to act upstream. Psychosocial stressors at work have been suggested as modifiable risk factors of low-grade inflammation, but few longitudinal studies have evaluated the association between these stressors and inflammatory biomarkers, such as C-reactive protein (CRP) and interleukin-6 (IL-6). OBJECTIVE: This longitudinal study evaluate the associations between exposure to psychosocial stressors at work and CRP and IL-6, separately and combined into an inflammatory index. METHODS: Data came from a cohort of 9188 white-collar workers recruited in 1991-1993 (T1) and followed-up after 8 (T2, 1999-2000) and 24 (T3, 2015-2018) years. Participants included in this study were randomly selected at T3 for serum biomarkers studies (n = 2557). CRP and IL-6 were measured using standardized protocols. Psychosocial stressors at work were assessed at T2 according to recognized models: Karasek's Demand-Control-Support model and Siegrist's Effort-Reward Imbalance (ERI) model, using validated questionnaires. High job strain was defined by an exposure to high psychological demand combined with low job control, and iso-strain was defined by an exposure to high job strain combined with low social support at work. ERI was defined by an imbalance between psychological demand and social, economic, and organizational reward. Several covariates were considered including sociodemographic, anthropometric, and lifestyle characteristics, and comorbidities. Prevalence ratios (PRs) and 95% confidence interval (CI) for the highest quartile of CRP, IL-6 and inflammatory index at T3 according to psychosocial stressors at work measured at T2 were calculated using generalized estimating equations. Multiple imputation and inverse probability of censoring weighting were done. RESULTS: In men, an association was observed between exposure to iso-strain and the inflammatory index (PR of 1.42 (95% CI: 1.06;1.90)), mainly among men aged less than 65 years (PR of 2.00 (95% CI: 1.37;2.92)). In this same age group, associations with inflammatory biomarkers were also observed among men with exposure to ERI, and among women with exposure to low reward at work or moderate social support at work. CONCLUSION: These results suggest that psychosocial stressors at work may increase low-grade inflammation. However, further studies are needed to corroborate these results and to clarify the potential differences between men and women. As these stressors are frequent and modifiable, their reduction is important for public health and could play a role in the primary prevention of chronic diseases.

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.

Long Working Hours and Risk of Recurrent Coronary Events.

BACKGROUND: Evidence from prospective studies has suggested that long working hours are associated with incident coronary heart disease (CHD) events. However, no previous study has examined whether long working hours are associated with an increased risk of recurrent CHD events among patients returning to work after a first myocardial infarction (MI). OBJECTIVES: The purpose of this study was to examine the effect of long working hours on the risk of recurrent CHD events. METHODS: This is a prospective cohort study of 967 men and women age 35 to 59 years who returned to work after a first MI. Patients were recruited from 30 hospitals across the province of Quebec, Canada. The mean follow-up duration was 5.9 years. Long working hours were assessed on average 6 weeks after their return to work. Incident CHD events (fatal or nonfatal MI and unstable angina) occurring during follow-up were determined using patients' medical files. Hazard ratios were estimated using Cox proportional hazard regression models. Splines and fractional polynomial regressions were used for flexible exposure and time modeling. RESULTS: Recurrent CHD events occurred among 205 patients. Participants working long hours (≥55 h/week) had a higher risk of recurrent CHD events after controlling for sociodemographics, lifestyle-related risk factors, clinical risk factors, work environment factors, and personality factors (hazard ratio vs. 35 to 40 h/week: 1.67; 95% confidence interval: 1.10 to 2.53). These results showed a linear risk increase after 40 h/week and a stronger effect after the first 4 years of follow-up and when long working hours are combined with job strain. CONCLUSIONS: Among patients returning to work after a first MI, longer working hours per week is associated with an increased risk of recurrent CHD events. Secondary prevention interventions aiming to reduce the number of working hours among these patients may lower the risk of CHD recurrence.

Effectiveness of a workplace intervention reducing psychosocial stressors at work on blood pressure and hypertension.

OBJECTIVES: To assess the effectiveness of a workplace intervention reducing psychosocial stressors at work in lowering blood pressure and hypertension prevalence. METHODS: The study design was a quasi-experimental pre-post study with an intervention group and a control group. Post-intervention measurements were collected 6 and 36 months after the midpoint of the intervention. Participants were all white-collar workers employed in three public organisations. At baseline, the intervention and the control groups were composed of 1088 and 1068 workers, respectively. The intervention was designed to reduce psychosocial stressors at work by implementing organisational changes. Adjusted changes in ambulatory blood pressure and hypertension prevalence were examined. RESULTS: Blood pressure and hypertension significantly decreased in the intervention group while no change was observed in the control group. The differential decrease in systolic blood pressure between the intervention and the control group was 2.0 mm Hg (95% CI: -3.0 to -1.0). The prevalence of hypertension decreased in the intervention group, when compared with the control group (prevalence ratio: 0.85 (95% CI: 0.74 to 0.98)). CONCLUSIONS: Findings suggest that psychosocial stressors at work are relevant targets for the primary prevention of hypertension. At the population level, systolic blood pressure reductions such as those observed in the present study could prevent a significant number of premature deaths and disabling strokes.

Job strain and incident cardiovascular disease: the confounding and mediating effects of lifestyle habits. An overview of systematic reviews.

This overview of systematic reviews (SR) aims to determine how the potential confounding and/or mediating effects of lifestyle habits were taken into consideration in SR examining the job strain effect on cardiovascular disease (CVD) incidence. Thirteen SR were identified. Lifestyle habits were often considered as confounders (n = 8). Authors reported that the job strain and CVD association remained after adjusting for lifestyle habits (n = 6); discussed lifestyle habits as potential mediators (n = 8) and postulated a total effect underestimation due to over-adjustment (n = 4). None investigated the magnitude of this bias.The effect of job strain on CVD is independent of lifestyle habits, supporting its causal effect on CVD. Lifestyle habits are also potential mediators. The current practice of adjusting for lifestyle habits can therefore lead to an underestimation of the total effect. Research using meditation methods is needed.