Cohort Profile: The PROspective Québec (PROQ) Study on Work and Health

Cardiovascular diseases (CVD) are the leading cause of mortality worldwide, accounting for 17.7 million deaths per year.1 CVD also rank first in terms of hospitalization costs in Canada,2 and are among the leading diagnoses for direct health expenditures in the USA.3 Mental health problems (MHP) are the first cause of disability worldwide.4 Their prevalence, long duration and high risk of recurrence5 place a considerable burden on health and social care systems and incur important productivity losses for employers.4 A number of prospective studies have documented the effects of adverse psychosocial work factors (work stressors) on CVD6,7 and MHP.8–11 To assess the exposure of psychosocial work factors, two theoretical models have mainly been used. The demand-control (DC) model suggests that workers simultaneously experiencing high psychological demands and low decision latitude, i.e. job strain, are more likely to develop stress-related health problems.12 The Siegrist’s effort-reward imbalance (ERI) model, proposes that efforts at work should be rewarded in various ways: income, respect and esteem, and occupational status control.13 Workers are in a state of detrimental imbalance when high efforts are accompanied by low reward, and are thus more susceptible to health problems. In industrialized countries, the proportions of working men and women exposed to these adverse factors at work have been found to be about 20–25%.14 The aim of The PROspective Québec (PROQ) Study on Work and Health is to further extend our comprehension of the effect of work stressors on cardiovascular and mental health, including a thorough examination of the pathways by which adverse psychosocial work factors accumulated over the working life could lead to higher risk of CVD and MHP at older ages. The PROspective Québec (PROQ) Study on Work and Health is a prospective cohort initiated in 1991-93, with two follow-ups 8 and 24 years later. Baseline (1991-93) and 8-year (1999-2001) follow-up data collections were funded by the Canadian Medical Research Council.15,16 The ongoing 24-year follow-up (2015-18) is supported by the Canadian Institutes of Health Research.17–20 This follow-up is a crucial phase, required to examine the effect of adverse psychosocial work factors exposure, accumulated over the working life, on: (i) the longitudinal progression of CVD and mental health outcomes assessed at earlier phases (blood pressure, psychological distress): (ii) CVD and MHP incidence before and after retirement; (iii) CVD and MHP social costs (health care costs and production losses costs) attributable to adverse psychosocial work factors exposure;20 and (iv) novel subclinical markers of disease risk (aortic stiffness, inflammatory markers, telomere length, cognitive function). These latter indicators intervene in the pathogenic process, leading to more severe form of diseases, and are therefore of great interest for early prevention. All white-collar workers employed in 19 public and semi-public organizations were invited to participate in the study. These organizations were participating in an epidemiological study of job strain and cardiovascular diseases that was coupled (for the purposes of recruitment and data collection) with a cardiovascular health promotion programme led by the regional Public Health Centre. About half of the organizations were selected by the researchers based on an a priori impression of possible exposure to job strain (jobs involving repetitive tasks and semi-public insurance companies, income tax services). Other organizations were selected by the cardiovascular health promotion programme team. A personalized letter was sent to every worker of the organizations, inviting them to participate. At baseline (1991–93), 9189 white-collar workers aged 18 to 65 years participated (participation proportion: 75%). Sociodemographic characteristics of the population are described in Table 1. Their jobs encompassed the full range of white-collar occupations, including senior management (10.4%), professional (35.5%), technical (20.8%) and office (30.6%) workers. Education levels ranged from no high-school diploma to university degree. At the baseline data collection, participants were met at their worksite during working hours in a room especially set aside. Data collection included a self-reported questionnaire, a face-to-face interview, anthropometric and clinical measurements and administrative databases extraction (Table 2). Sociodemographic characteristics of the PROspective Québec (PROQ) Study on Work and Health Sociodemographic characteristics of the PROspective Québec (PROQ) Study on Work and Health Measurements at each phase of the PROQ-Study on Work and Health Measurements at each phase of the PROQ-Study on Work and Health At the first follow-up 8 years later (1999–2001), 8121 agreed to participate again, corresponding to 89% of the initial sample. There were 117 deaths (1.2%) and 744 refusals (7.7%). For the ongoing 24-year follow-up (2015–18), 9020 of participants from the initial cohort (98.1%) were retraced. Approximately 63% of all participants are now aged over 60 years and about 70% of them are retired. Among retired participants, for whom data collection has already begun, a participation of 74% is actually attained. We expect to obtain a final proportion of ≥ 80% for questionnaires and anthropometric and clinical measures, and written consent of ≥ 95% of the cohort sample to access medico-administrative data for cardiovascular and mental health events. Retired participants are met in specially designed rooms at the Hospital du Saint-Sacrement du CHU de Québec (Québec City, Canada). Active workers are met at their workplace, during regular working hours. Table 2 summarizes all the variables measured at the three time points for each procedure, namely self-reported questionnaire, interview, biological variables and medico-administrative databases. Psychological demands (PD) and decision latitude (DL) were assessed with both 9-item scales of the Karasek’s Job Content Questionnaire.12 The results of previous studies have supported the psychometric properties (internal consistency, factorial validity and discriminant validity) of both the original English21 and French version of the questionnaire.22,23 PD refer to an excessive work load, very hard or very fast work, task interruption, intense concentration and conflicting demands. DL reflects opportunities for learning, autonomy and participation in the decision-making process. Psychological demands and decision latitude were computed according to the algorithms recommended by Karasek.12 Workers with PD scores of 24 or higher (the median for the general Québec working population) were classified as having high PD. Workers with DL scores of 72 or lower (median of general Québec working population) were classified as having low DL.24 The passive group comprised workers with low PD and low DL, the active group comprised workers with high PD and high DL, and the job strain (high strain) group comprised workers with high PD and low DL. Other workers were classified as unexposed. The effort-reward imbalance (ERI) model proposes that efforts at work should be rewarded in various ways: income, respect and esteem, and occupational status control. Workers are in a state of detrimental imbalance when high efforts are accompanied by low reward, and are thus more susceptible to health problems. Efforts and reward were respectively measured with 4 and 11 items on a 4-point Likert scale adapted from the original Siegrist’s questionnaire.13 The factorial validity and internal consistency of both the original English and the French versions of this instrument have been demonstrated.25,26 Scores of effort and reward were calculated with the sum of items, and the ERI ratio was obtained by divided the score of effort by the score of reward. Annual exposure to psychosocial work factors from the demand-control model will be defined using a job exposure matrix. This matrix will be created from the professional history of each subject and the average exposure scores per job title. Professional history covering the whole study period will be retrieved from registries of all organizations. Job title will be obtained for all occupied positions. Mean exposure scores will be computed using recommended methods, adjusting for age, gender and education.27 Annual exposure will be estimated using the job exposure matrix Casual blood pressure was measured following the American Heart Association protocol.28 Workers’ blood pressure (BP) was measured at rest after they had been sitting for 5 min. The averages of two blood pressure measurements taken at baseline and three taken at follow-up, 1 to 2 min apart, was used as baseline and follow-up blood pressure levels. At the 24-year follow-up, BP was measured by trained personnel using a validated automated oscillometric device (Microlife Watch BP Office) to improve precision and validity.29 Moreover, blood pressure measurements were performed on both arms simultaneously for assessing inter-arm blood pressure differences. After the participant had been sitting for 5 min, three readings were taken on both arms and registered automatically on the Microlife software. Ambulatory blood pressure (ABP) was measured in a subsample composed of approximately 2200 workers from three public insurance institutions. They were contacted by the researchers to conduct a prospective examination within a shorter time span of the cumulative effect of adverse psychosocial work exposures on ambulatory blood pressure in middle-aged workers. More than half (N = 1240) were employed in an organization included in the main study sample, and workers from two other organizations also participated in this additional prospective examination. Workers from the main study sample and the ambulatory blood pressure subsample share the same distribution of sociodemographic factors, occupational characteristics and adverse psychosocial exposures at work. Data collection was performed at three time points in a distinct period: at baseline (2000–04), 3 years later (2004–06) and 5 years later (2006–09). At each measurement time, ABP was assessed by the Spacelabs 90207 oscillometric devices.30,31 The device was installed on the non-dominant arm if BP difference measured on both arms was inferior to 10 mmHg. Otherwise, it was installed on the arm showing the higher BP level. ABP was measured every 15 min during daytime working hours. ABP was defined as the mean of all readings taken during the working day. Information on blood pressure will be merged among workers participating in both samples, to provide additional insights on BP trajectories over the whole follow-up. Arterial stiffness is measured with carotid-femoral pulse wave velocity (PWV) according to actual recommendations,32 using the Complior Analyses Device.33 Carotid-femoral velocity was measured from the carotid-femoral distance and the transit time between the carotid and the femoral pulse, recorded simultaneously. In each participant, PWV was measured twice, and if the difference in velocity between the two measurements was larger than 0.5 m/s, a third measurement was taken. Inter- and intra-observor reproducibility was assessed in previous studies and found to be excellent.34,35 CVD incidence is assessed using medico-administrative databases, including: the hospitalization (MEDECHO) database; the Québec medical claims database from the public health insurance system in Québec (RAMQ); and the death registry. Information on the following CVD events is retrieved: acute myocardial infarction, unstable angina, acute stroke, atrial fibrillation, peripheral vascular diseases and revascularization. Psychological distress was measured using a validated 14-item version of the Psychiatric Symptom Index (PSI).36–38 The PSI assessed the presence and intensity of a range of symptoms: anxiety, depression, aggressiveness and minor cognitive impairment, during the previous week. The validity of the French version of the PSI has been demonstrated and has a good concurrent validity with four other mental health measures: consultation with a professional, hospitalization, suicidal ideation or suicide attempt and use of psychotropic medication.39 At the 24-year follow-up, we have included the K6 questionnaire, elaborated and validated by Kessler et al. Because of its brevity and good validity, it is now the main instrument used in major health surveys in Canada40 and specifically Québec.41 The K6 includes six questions covering the two most frequent distress symptoms, i.e. depressive symptoms and anxiety. Medically certified work absences were obtained retrospectively from computerized records from the employers’ unique insurance service. The covered period was from 1 year before study baseline to the end of follow-up. Data included the exact date of each work absence episode. The work absence policy was the same for each employer. For each episode of 3 days or more, workers had to provide a medical certificate from a physician to their employer. These data were rigorously verified by employers because they were used to pay indemnity to workers. Diagnoses on medical certificates are coded by a medical archivist using ICD-9 and ICD-10.42 The prevalence of depression was measured at the 24-year follow-up (2015-18) using the validated French version of the Composite International Diagnostic Interview-Short Form (CIDI-SF). This instrument measures depression according to the definitions and criteria of the DSM-IV, and assesses the occurrence of symptoms of a major depressive episode within the past 12 months. The CIDI-SF was validated by the World Health Organization (WHO)43 and recently used in Canadian population-based studies.44,45 Depression incidence over the follow-up was measured using the hospitalization and medical claims databases as well as the employer’s registry of medically certified work absences for depression. Cognitive function was assessed using the Montréal Cognitive Assessment (MoCA). The MoCA test is designed to detect mild cognitive impairment (MCI).46 It is a global cognitive function 30-point short test which evaluates different domains: visuospatial abilities, executive functions, short-term memory recall, attention, concentration, working memory, language and orientation to time and space. The original validation study compared the MoCA with the Mini Mental State Examination (MMSE),- another test for global cognitive performance. The MMSE had a sensitivity of 18% to detect MCI, whereas the MoCA detected 90% of MCI subjects. In the mild Alzheimer’s disease group, the MMSE had a sensitivity of 78%, whereas the MoCA detected 100%. Specificity was excellent for both MMSE and MoCA (100% and 87%, respectively). Studies examining the individual MoCA domains with more comprehensive and commonly used neuropsychological measures showed further support for the use of the MoCA as a cognitive screen that reflects sconstructs similar to those measured by a comprehensive battery.47,48 Total cholesterol was measured at baseline using the Boehringer Mannaheim Reflotron Chemistry Analyser.49 Blood samples for measurements of inflammatory markers and telomeres were performed by a qualified research nurse using a standardized protocol, in 2015-18. Blood samples were collected in EDTA-treated tubes and in tubes with gel serum separator, processed and stored at −80°C until analysis. C-reactive protein (CRP) and interleukin 6 (IL-6) were measured following strict quality assurances procedures. CRP serum concentrations were measured using high-sensivity immunoturbidimetric assay on the Roche Modular analytical system (Roche Diagnostics, Indianapolis, IN). IL-6 serum concentrations were measured using enzyme-linked immunosorbent assay (ELISA), according to the manufacturer’s protocol (R & D Systems, Minneapolis, MN, USA) and the signal was measured using an automated fluorometer. For telomere measurement, leukocyte genomic DNA was extracted using QIAamp blood minikit (QIAGEN Inc., Missisauga, ON).50 Telomere length was measured using a highly reproducible quantitative polymerase chain reaction (PCR) method in peripheral white blood cells. This technique was validated by Southern blot.51,53 Glycated haemoglobin will be measured in a subsample of active and recently retired workers using immunochemical assay on a Roche Diagnostics Integra platform [coefficient of variation (CV), 1.6%]. Serum creatinine will be dosed using the Jaffe method on a Siemens Advia 1800 automated analyser ratio will be measured using an immunoturbidimetric assay on a Siemens Advia 1800 analyser ratio will be dosed in the sample using an method data included are health care costs costs) and costs to production losses and to CVD and as measured from the Health care costs medical and and room from the public health insurance databases in Québec costs to production losses will medically certified work absences and years of production because of death and at work is measured at the ongoing 24-year follow-up (2015-18) among active workers using the Work and The measures productivity and costs for various health problems including CVD and The of the proportion of these CVD and MHP costs attributable to psychosocial work factors is based on attributable which risk and prevalence of exposure using cohort included were age, a and was defined by and was measured by trained ratio was also measured as a of history of social support work, social and life were measured using the self-reported The following were also social support at and were measured for the first time in the ongoing follow-up, including social care of a or and in the social In retired participants, working after the date was also was in using an questionnaire, validated in a Québec was with a standardized and validated the we have documented the validity of the French version of the instrument used to psychosocial work factors from the demand-control We have also demonstrated that the prevalence of these adverse psychosocial work factors was which is to that of the general population of Québec and of other industrialized countries, the public health of these We have that adverse psychosocial work factors are with an prevalence of CVD risk factors as and We have documented the adverse effect of job strain exposure on blood psychological and psychotropic the subsample with ambulatory blood pressure measurements (N = we showed that job strain and effort-reward imbalance are with and 5 in ambulatory blood and with a higher prevalence of We have also that these adverse psychosocial exposures at work have an effect on psychological and medically certified absence for mental health Analyses among women also documented the effect of adverse psychosocial work factors exposure and high on blood The cohort has Blood pressure measures were based on a number of as is of most epidemiological were three psychosocial work factors over the 24-year exposure The job exposure matrix will to this the study population was composed of white-collar and thus the results to other the prevalence of exposure to adverse psychosocial work factors in the cohort was similar to that of the Québec general working This cohort has important (i) it was in a sample of men and (ii) the participation proportion at baseline was the proportion was 89% at first follow-up and at the ongoing follow-up, 80% participation is for the data collection and 95% for medico-administrative (iii) validated were used to adverse psychosocial work (iv) the of psychosocial work factors cumulative exposure to be at or later life, a number of CVD and mental health outcomes were measured as well as their major risk and the costs of CVD and MHP attributable to adverse psychosocial work factors were assessed with a longitudinal including a set of direct and costs are highly the corresponding with The aim of The PROspective Québec (PROQ) Study on Work and Health is to further extend our comprehension of the effect of work stressors on cardiovascular and mental The effect of adverse psychosocial work exposure, accumulated over the working life, will be using cardiovascular (CVD) and mental health (MHP) measured before and after among men and The cohort is in Québec City, Baseline data collection (1991-93) in the recruitment of 9189 white-collar workers aged 18 to 65 At the first follow-up, 8 years later 8121 agreed to participate of the initial For the ongoing 24-year follow-up 9020 of participants from the initial cohort (98.1%) were retraced. We expect to obtain a final participation of ≥ 80% for anthropometric and clinical measures and participation of ≥ 95% of the cohort sample, to access medico-administrative data adverse psychosocial work exposure strain, effort-reward cardiovascular outcomes (blood pressure, stiffness, CVD mental health outcomes medically certified depression, and including main CVD and MHP risk are highly the corresponding This work was supported by the Medical Research of number and the Canadian Institutes of Health Research of All the no of The PROspective Québec (PROQ) Study on Work and and by all in Québec Québec Québec Québec Québec Québec Québec Québec Québec Québec Québec Québec de Québec Québec Québec Québec of and du Québec Québec Québec Québec de et de Montréal Québec

Récupéré en direct depuis OpenAlex et désinversé. Les résumés ne sont pas conservés dans cette base de données : les index inversés représentent 8,6 Go des 9,3 Go de texte de la base, et le serveur dispose de 13 Go libres.