Environnement psychosocial au travail et pression artérielle ambulatoire : une étude prospective

Objectifs: 1. Mesurer l’effet de la durée d’exposition aux contraintes psychosociales au travail sur la pression artérielle (PA) ambulatoire et l’incidence cumulative de l’hypertension sur une période de 5 ans. 2. Examiner l’effet indépendant et complémentaire des modèles demande-latitude (DL) et déséquilibre efforts-reconnaissance (DER) comme déterminant de la PA ambulatoire. 3. Examiner l'effet intermédiaire de l’indice de masse corporelle (IMC) dans la relation entre l’exposition aux contraintes psychosociales du modèle DER et l’évolution de la PA. 4. Examiner l'association entre les contraintes psychosociales du modèle DL et la prévalence de l'hypertension masquée (HM). Méthodes : La cohorte est constituée de 2 300 femmes et hommes occupant des emplois de cols blancs. Les données ont été récoltées à trois reprises, sur une période de 5 ans. À chaque temps, les contraintes psychosociales au travail ont été mesurées en utilisant des instruments validés. La PA a été mesurée à chaque 15 minutes, durant une journée de travail. Résultats : Les hommes ayant été chroniquement exposés à un emploi actif avaient une élévation de la PA systolique (+2.7 mmHg) et diastolique (+2.5 mmHg) ainsi qu’une incidence cumulative d’hypertension (RR = 2,20, 95% IC 1,50-3,23) plus élevée que les hommes non exposés. Chez les femmes, la survenue de l’exposition au DER était associée à l’augmentation de la PA systolique (+2.8 mmHg) et diastolique (+1.6 mmHg). Les contraintes psychosociales du modèle DL étaient associées à la PA, mesurée au même moment, chez les hommes. Cet effet était toutefois atténué après ajustement pour le modèle DER. Les hommes et les femmes exposés au DER avaient respectivement une PA plus élevée de +1,4/+1,4 mmHg et de +1,6/+1,3 mmHg, indépendamment de l’exposition au modèle DL. L’exposition chronique au DER étaient associées à l’augmentation de la PA indirectement, via l’IMC, chez les femmes ayant un IMC élevé au départ (≥25 kg/m2). Les hommes ayant un emploi actif avaient une prévalence plus élevée d’hypertension masquée (RC = 2,07, 95% CI 1,30-3,31). Conclusion : Cette thèse supporte l’effet délétère de l’exposition aux contraintes psychosociales au travail sur la PA. La réduction des contraintes psychosociales au travail comporte un potentiel important de prévention primaire des problèmes de santé cardiovasculaire.Objectives: 1. To measure the effect of repeated exposure to psychosocial work factors from the demand-control (DC) and ERI effort-reward imbalance (ERI) models on ABP over 5 years 2. To examine the independent and combined effect of DC and ERI on ABP 3. To examine the mediating effect of body mass index (BMI) in the association between ERI and ambulatory blood pressure (ABP) over 5 years. 4. To examine the association between psychosocial work factors from the DC model and masked hypertension prevalence. Methods: The study population was composed of 2,300 white-collar workers. They were assessed three times during a 5-year period (Year 1, 3 and 5). At each time, psychosocial work factors were measured using validated scales. ABP was measured every 15 minutes during a working day. Results: Men who were always exposed to an active job had higher systolic and diastolic ABP increases (+2.7/+2.5 mmHg) and a higher cumulative incidence of hypertension (RR = 2.20, 95% C.I. 1.50–3.23), compared to never exposed men. In women, ERI exposure onset was associated with higher increases in systolic (+2.8 mmHg) and diastolic (+1.6 mmHg) ABP, compared to never exposed women. Men exposed to psychosocial work factors from the DC model had higher ABP compared to unexposed men, using contemporaneous exposure. However, the high strain/ABP association was not significant after adjustment for ERI. Men (+1.4/+1.4 mmHg) and women (+1.6/+1.3 mmHg) exposed to ERI had higher ABP, after adjustment for DC exposure. In the prospective analyses using ERI exposure over 3 years, BMI mediated the effect of ERI exposure onset, ERI chronic exposure and ABP, in women with baseline BMI ≥25 kg/m2. For men, being active exposure was associated with masked hypertension (Adjusted OR: 2.07, 95% CI 1.30-3.31). Conclusion: In the present study, repeated exposure to psychosocial work factors from the DC and ERI models was associated with significant increases in ABP and hypertension. DC and ERI models had independent effect on ABP. In women, repeated exposure to psychosocial work factors from the ERI model was indirectly associated with BP increases, via BMI increases while exposure to psychosocial work factors from the DC model was associated with masked hypertension, in men

Polyconsommation d’alcool et de cannabis et comportements à risque chez les étudiants universitaires canadiens : une analyse situationnelle

La polyconsommation d’alcool et de cannabis est rapportée par un grand nombre de jeunes adultes canadiens (Flight, 2007). Les recherches épidémiologiques suggèrent que le statut de polyconsommateur est associé à certains comportements à risque, dont la consommation excessive d’alcool et la conduite d’un véhicule automobile sous l’influence de l’alcool (Jones et al. 2001; Mohler-Kuo, et al. 2003; Shillington & Clapp, 2006). Les études qui soutiennent le risque accru de comportements à risque pour les polyconsommateurs se focalisent sur l’effet des substances. En rupture avec cette approche, ce mémoire présente une étude situationnelle de la polyconsommation en examinant l’effet du statut de polyconsommateur et, pour ceux-ci l’effet de la consommation simultanée d’alcool et de cannabis, en situant l’action dans son contexte de survenu et en examinant la contribution du contexte. La probabilité d’avoir conduit une voiture sous l’influence de l’alcool et d’avoir consommé excessivement de l’alcool sera examinée auprès d’étudiants universitaires. La contribution respective des substances, des situations et de l’expérience de la vie universitaire sera examinée. La méthodologie employée repose sur la construction de modèles de régression logistique multiniveaux, à la fois chez l’ensemble des buveurs (10 747 occasions, nichées dans 4396 buveurs) et dans le sous-échantillon des polyconsommateurs (2311 occasions de consommation d’alcool, nichées dans 880 polyconsommateurs). Les données sont issues de l’Enquête sur les campus canadiens (2004), menée auprès d’un échantillon représentatif de 6282 étudiants issus de 40 universités. Le statut de polyconsommateur est associé à la consommation excessive d’alcool, mais pas à la conduite d’une voiture suite à la consommation. Cependant, la consommation simultanée d’alcool et de cannabis n’est pas associée à un risque plus élevé de consommer excessivement de l’alcool, et est négativement associée à la conduite d’une voiture après la consommation. Plusieurs caractéristiques situationnelles sont associées aux deux comportements à l’étude et diminuent la force d’association entre ces comportements et le statut de polyconsommateur.Alcohol and cannabis polydrug use is a common consumption pattern among Canadian young adults (Flight, 2007). Moreover, epidemiological studies suggest that alcohol and cannabis use is associated with other risky behaviours such as binge drinking and driving a vehicle under the influence of both substances (Jones et al. 2001; Mohler-Kuo et al. 2003; Shillington & Clapp, 2006). Studies which have reported an increased risk for polydrug users focus on substance use. The present study propose a situational approach, in which the effect of poly drug use, as well as the effect of simultaneous use on these risky behaviours are investigated while considering the context in which the consumption takes place. The probability of driving under the influence of alcohol, and the probability of binge drinking are examined among a sample of university students. The respective contribution of substance use, university life experience and drinking situations is examined. The methodology used to perform this study is based on multilevel logistic regression models, among drinkers (10 747 occasions, nested within 4396 drinkers) as well as among the polydrug users subsample (2311 drinking occasions, nested within 880 individuals). The data are drawn from the Canadian Campus Survey conducted in 2004 with a random nationally representative sample of 6282 students from 40 universities. Polydrug status is positively associated with episodic binge drinking, but not with driving under the influence of alcohol. However, cannabis use is not associated with binge drinking, among polydrug users. Moreover, for this specific population, cannabis smoking is negatively associated with driving under the influence of alcohol. Several situational characteristics are associated with either one or both studied behaviours and partially explain the relationship between those behaviours and polydrug use

A test for the correct specification of marginal structural models

Marginal structural models (MSMs) allow estimating the causal effect of a time‐varying exposure on an outcome in the presence of time‐dependent confounding. The parameters of MSMs can be estimated utilizing an inverse probability of treatment weight estimator under certain assumptions. One of these assumptions is that the proposed causal model relating the outcome to exposure history is correctly specified. However, in practice, the true model is unknown. We propose a test that employs the observed data to attempt validating the assumption that the model is correctly specified. The performance of the proposed test is investigated with a simulation study. We illustrate our approach by estimating the effect of repeated exposure to psychosocial stressors at work on ambulatory blood pressure in a large cohort of white‐collar workers in Québec City, Canada. Code examples in SAS and R are provided to facilitate the implementation of the test

Persistence and Progression of Masked Hypertension: A 5-Year Prospective Study

Objectives. To examine masked hypertension persistence over 5 years. Methods. White-collar workers were recruited from three public organizations. Blood pressure (BP) was measured using Spacelabs 90207. Manually operated BP was defined as the mean of the first three readings taken at rest. Ambulatory BP was defined as the mean of the next readings taken every 15 minutes and recorded during working hours. BP was assessed three times over 5 years. Masked hypertension was defined as manually operated BP less than 140 and less than 90 mmHg and ambulatory BP at least 135 or at least 85 mmHg. Sustained hypertension was defined as manually operated BP at least 140 or at least 90 mmHg and ambulatory BP at least 135 or at least 85 mmHg or being treated for hypertension. Results. BP measurements were obtained from 1669 participants from whom 232 had masked hypertension at baseline. Persistence of masked hypertension was 38% and 18.5%, after 3 and 5 years, respectively. Progression to sustained hypertension was 26% and 37%, after 3 and 5 years, respectively. Conclusion. Among baseline masked hypertensives, one-third progressed to sustained hypertension and about one out of five remained masked after 5 years, potentially delaying diagnosis and treatment

Psychosocial work factors and social inequalities in psychological distress: a population-based study.

BACKGROUND: Mental health problems (MHP) are the leading cause of disability worldwide. The inverse association between socioeconomic position (SEP) and MHP has been well documented. There is prospective evidence that factors from the work environment, including adverse psychosocial work factors, could contribute to the development of MHP including psychological distress. However, the contribution of psychosocial work factors to social inequalities in MHP remains unclear. This study evaluates the contribution of psychosocial work factors from two highly supported models, the Demand-Control-Support (DCS) and the Effort-Reward Imbalance (ERI) models to SEP inequalities of psychological distress in men and women from a population-based sample of Quebec workers. METHODS: Data were collected during a survey on working conditions, health and safety at work. SEP was evaluated using education, occupation and household income. Psychosocial work factors and psychological distress were assessed using validated instruments. Mean differences (MD) in the score of psychological distress were estimated separately for men and women. RESULTS: Low education level and low household income were associated with psychological distress among men (MD, 0.56 (95% CI 0.06; 1.05) and 1.26 (95% CI 0.79; 1.73) respectively). In men, the contribution of psychosocial work factors from the DCS and the ERI models to the association between household income and psychological distress ranged from 9% to 24%. No clear inequalities were observed among women. CONCLUSIONS: These results suggest that psychosocial work factors from the DCS and the ERI models contribute to explain a part of social inequalities in psychological distress among men. Psychosocial factors at work are frequent and modifiable. The present study supports the relevance of targeting these factors for the primary prevention of MHP and for health policies aiming to reduce social inequalities in mental health

Assessment of the healthy worker survivor effect in the relationship between psychosocial work-related factors and hypertension.

OBJECTIVES: The healthy worker survivor effect (HWSE) usually leads to underestimation of the effects of harmful occupational exposures. HWSE is characterised by the concomitance of three associations: (1) job status-subsequent exposure, (2) job status-disease and (3) previous exposure-job status. No study has reported the coexistence of these associations in the relationship between psychosocial work-related factors and health. We assessed if HWSE is present when measuring the effects of cumulative exposure to psychosocial work-related factors on the prevalence of hypertension in white-collar workers. METHODS: Data were obtained from two timepoints (1991-1993 at baseline and 1999-2001 at follow-up) of a prospective cohort study. At baseline, the population was composed of 9188 white-collar employees (women: 49.9%) in Quebec City. Job strain as psychosocial work-related factor and blood pressure were measured using validated methods. Job status (retirees vs employees) at follow-up was self-reported. Multiple multilevel robust Poisson regressions were used to estimate prevalence ratios of hypertension and risk ratios of retirement separately by gender. We performed multiple imputations to control selection bias due to missing values. RESULTS: Retirement eliminated the subsequent exposure to job strain de facto and was associated with the reduction in the prevalence of hypertension in younger (-33%) and older (-11%) men and in older women (-39%). Job strain was associated with job status in younger men and in women of any age. CONCLUSION: Data showed the presence of HWSE in younger men and older women given the coexistence of the three structural associations

Socioeconomic status, education, and aortic stiffness progression over 5 years: the Whitehall II prospective cohort study.

OBJECTIVE: The inverse association between socioeconomic status (SES) and cardiovascular disease (CVD) risk is well documented. Aortic stiffness assessed by aortic pulse wave velocity (PWV) is a strong predictor of CVD events. However, no previous study has examined the effect of SES on arterial stiffening over time. The present study examines this association, using several measures of SES, and attained education level in a large ageing cohort of British men and women. METHODS: Participants were drawn from the Whitehall II study. The sample was composed of 3836 men and 1406 women who attended the 2008-2009 clinical examination (mean age = 65.5 years). Aortic PWV was measured in 2008-2009 and in 2012-2013 by applanation tonometry. A total of 3484 participants provided PWV measurements on both occasions. The mean difference in 5-year PWV change was examined according to household income, education, employment grade, and father's social class, using linear mixed models. RESULTS: PWV increase [mean: confidence interval (m/s)] over 5 years was higher among participants with lower employment grade (0.38: 0.11-0.65), household income (0.58, 95%: 0.32-0.85), and education (0.30: 0.01, 0.58), after adjusting for sociodemographic variables, BMI, alcohol consumption, smoking, and other cardiovascular risk factors, namely SBP, mean arterial pressure, heart rate, cholesterol, diabetes, and antihypertensive use. CONCLUSION: The present study supports the presence of robust socioeconomic disparities in aortic stiffness progression. Our findings suggest that arterial aging could be an important pathophysiological pathway explaining the impact of lower SES on CVD risk

A test for the correct specification of marginal structural models

Marginal structural models (MSMs) allow estimating the causal effect of a time‐varying exposure on an outcome in the presence of time‐dependent confounding. The parameters of MSMs can be estimated utilizing an inverse probability of treatment weight estimator under certain assumptions. One of these assumptions is that the proposed causal model relating the outcome to exposure history is correctly specified. However, in practice, the true model is unknown. We propose a test that employs the observed data to attempt validating the assumption that the model is correctly specified. The performance of the proposed test is investigated with a simulation study. We illustrate our approach by estimating the effect of repeated exposure to psychosocial stressors at work on ambulatory blood pressure in a large cohort of white‐collar workers in Québec City, Canada. Code examples in SAS and R are provided to facilitate the implementation of the test

Coexistence du français et des langues nationales dans les pays francophones

La coexistence du français et des langues nationales est un problème essentiel dans la Francophonie, tout simplement parce que, la France exceptée, le français n’est langue unique dans aucun pays francophone ; il est concurrencé ou il est au contact avec d’autres langues. Dans un pays où la langue nationale n’est pas le français, on veillera donc à ce que le français n’entre pas en conflit avec cette langue. Nous sommes les uns et les autres tout à fait attachés à ce que la langue française s..