Respective Mediating Effects of Social Position and Work Environment on the Incidence of Common Cardiovascular Risk Factors.

Background Social position and work environment are highly interrelated and their respective contribution to cardiovascular risk is still debated. Methods and Results In a cohort of 20 625 French workers followed for 25 years, discrete-time survival analysis with reciprocal mediating effects, adjusted for sex, age, and parental history of early coronary heart disease, was performed using Bayesian structural equation modeling to simultaneously investigate the extent to which social position mediates the effect of work environment and, inversely, the extent to which work environment mediates the effect of social position on the incidence of common cardiovascular risk factors. Depending on the factor, social position mediates 2% to 53% of the effect of work environment and work environment mediates 9% to 87% of the effect of social position. The mediation by work environment is larger than that by social position for the incidence of obesity, hypertension, dyslipidemia, diabetes, sleep complaints, and depression (mediation ratios 1.32-41.5, 6.67 when modeling the 6 factors together). In contrast, the mediation by social position is larger than that by work environment for the incidence of nonmoderate alcohol consumption, smoking, and leisure-time physical inactivity (mediation ratios 0.16-0.69, 0.26 when modeling the 3 factors together). Conclusions The incidence of behavioral risk factors seems strongly dependent on social position whereas that of clinical risk factors seems closely related to work environment, suggesting that preventive strategies should be based on education and general practice for the former and on work organization and occupational medicine for the latter.

Work environment mediates a large part of social inequalities in the incidence of several common cardiovascular risk factors: Findings from the Gazel cohort.

Whether working conditions contribute to social inequalities in cardiovascular disease is still a matter of debate. The present study investigates the extent to which the social gradient in the incidence of common behavioral and clinical risk factors is explained by work environment. In a well-characterized cohort of 20,625 middle-aged French civil servants followed for 25 years, social status and work environment were globally measured at baseline by combining respectively four socioeconomic indicators (education, wealth, income, occupational grade) and 25 physical, biomechanical, organizational and psychosocial occupational exposures. These 2 global measures are strongly correlated with each other (p < 0.0001), lower is social status, worse is work environment. In proportional hazard regression models adjusted for sex, age and parental cardiovascular disease, low social status increases the incidence of 9 risk factors with hazard ratios ranging from 1.12 to 1.72 while bad work environment increases the incidence of 7 risk factors with hazard ratios ranging from 1.15 to 2.02. Structural equation models to discrete-time survival analysis with moderated mediation show that bad work environment explains nearly 50% of the global effect of low social status on the incidence of the 9 risk factors (p < 0.01). This mediating effect varies substantially from one risk factor to another, explaining 32-39% of social gradients in the risk of physical inactivity, obesity, diabetes, dyslipidemia and 64-90% of gradients in the risk of hypertension, sleep complaints and depression (all p < 0.01). No significant mediating effect of work environment is found for social gradients in the incidence of non-moderate alcohol consumption and smoking. These results suggest that work environment mediates a large part of the social gradient in the incidence of several common cardiovascular risk factors, emphasizing the necessity to include working conditions in policies aimed to reduce social inequalities in health.

A Global View of the Relationships between the Main Behavioural and Clinical Cardiovascular Risk Factors in the GAZEL Prospective Cohort.

Although it has been recognized for a long time that the predisposition to cardiovascular diseases (CVD) is determined by many risk factors and despite the common use of algorithms incorporating several of these factors to predict the overall risk, there has yet been no global description of the complex way in which CVD risk factors interact with each other. This is the aim of the present study which investigated all existing relationships between the main CVD risk factors in a well-characterized occupational cohort. Prospective associations between 12 behavioural and clinical risk factors (gender, age, parental history of CVD, non-moderate alcohol consumption, smoking, physical inactivity, obesity, hypertension, dyslipidemia, diabetes, sleep disorder, depression) were systematically tested using Cox regression in 10,736 middle-aged individuals free of CVD at baseline and followed over 20 years. In addition to independently predicting CVD risk (HRs from 1.18 to 1.97 in multivariable models), these factors form a vast network of associations where each factor predicts, and/or is predicted by, several other factors (n = 47 with p<0.05, n = 37 with p<0.01, n = 28 with p<0.001, n = 22 with p<0.0001). Both the number of factors associated with a given factor (1 to 9) and the strength of the associations (HRs from 1.10 to 6.12 in multivariable models) are very variable, suggesting that all the factors do not have the same influence within this network. These results show that there is a remarkably extensive network of relationships between the main CVD risk factors which may have not been sufficiently taken into account, notably in preventive strategies aiming to lower CVD risk.

Occupational biomechanical exposure predicts low back pain in older age among men in the Gazel Cohort.

PURPOSE: Occupational biomechanical exposures are considered as risk factors for low back pain in the working population. It has also been suggested that their effects persist after retirement. Our objectives were to assess the role of past biomechanical occupational exposure on low back pain in early old age among male participants of the Gazel Cohort. METHODS: Low back pain for more than 30 days in the past 12 months (LBP30) was assessed in 1996 and 2006 using a French version of the Nordic questionnaire in a subsample of the Gazel Cohort. Logistic regression models were used to study associations between LBP30 in 2006 and past occupational biomechanical exposure, self-reported in 1996, taking into account personal and psychosocial work factors self-reported in 1996, and the date of retirement provided by the company. A multinomial model served to study persistent and new cases, according to LBP30 in 1996. RESULTS: We studied 1,520 men aged 58-67 in 2006, most of them retired. Low back pain for more than 30 days in the past 12 months reported in 2006 was related to occupational biomechanical exposure encountered many years earlier (OR 1.55, 95% CI 1.05-2.27 for 10-20 years of exposure to bending/twisting, OR 1.71, 95% CI 1.17-2.49 for >20 years). These associations appeared specific to low back pain for more than 30 days in the past 12 months which persisted between 1996 and 2006. CONCLUSION: These results suggest that occupational biomechanical exposure during active life has persistent effects among men in early old age, even for people who left the workforce. They point out the importance of preventive measures at work for better health later and appear relevant for policy-making decisions concerning age at retirement.

Work stress and risk of cancer: meta-analysis of 5700 incident cancer events in 116,000 European men and women.

OBJECTIVE: To investigate whether work related stress, measured and defined as job strain, is associated with the overall risk of cancer and the risk of colorectal, lung, breast, or prostate cancers. DESIGN: Meta-analysis of pooled prospective individual participant data from 12 European cohort studies including 116,056 men and women aged 17-70 who were free from cancer at study baseline and were followed-up for a median of 12 years. Work stress was measured and defined as job strain, which was self reported at baseline. Incident cancers (all n=5765, colorectal cancer n=522, lung cancer n=374, breast cancer n=1010, prostate cancer n=865) were ascertained from cancer, hospital admission, and death registers. Data were analysed in each study with Cox regression and the study specific estimates pooled in meta-analyses. Models were adjusted for age, sex, socioeconomic position, body mass index (BMI), smoking, and alcohol intake RESULTS: A harmonised measure of work stress, high job strain, was not associated with overall risk of cancer (hazard ratio 0.97, 95% confidence interval 0.90 to 1.04) in the multivariable adjusted analyses. Similarly, no association was observed between job strain and the risk of colorectal (1.16, 0.90 to 1.48), lung (1.17, 0.88 to 1.54), breast (0.97, 0.82 to 1.14), or prostate (0.86, 0.68 to 1.09) cancers. There was no clear evidence for an association between the categories of job strain and the risk of cancer. CONCLUSIONS: These findings suggest that work related stress, measured and defined as job strain, at baseline is unlikely to be an important risk factor for colorectal, lung, breast, or prostate cancers.

Job strain and tobacco smoking: an individual-participant data meta-analysis of 166,130 adults in 15 European studies.

BACKGROUND: Tobacco smoking is a major contributor to the public health burden and healthcare costs worldwide, but the determinants of smoking behaviours are poorly understood. We conducted a large individual-participant meta-analysis to examine the extent to which work-related stress, operationalised as job strain, is associated with tobacco smoking in working adults. METHODOLOGY AND PRINCIPAL FINDINGS: We analysed cross-sectional data from 15 European studies comprising 166,130 participants. Longitudinal data from six studies were used. Job strain and smoking were self-reported. Smoking was harmonised into three categories never, ex- and current. We modelled the cross-sectional associations using logistic regression and the results pooled in random effects meta-analyses. Mixed effects logistic regression was used to examine longitudinal associations. Of the 166,130 participants, 17% reported job strain, 42% were never smokers, 33% ex-smokers and 25% current smokers. In the analyses of the cross-sectional data, current smokers had higher odds of job strain than never-smokers (age, sex and socioeconomic position-adjusted odds ratio: 1.11, 95% confidence interval: 1.03, 1.18). Current smokers with job strain smoked, on average, three cigarettes per week more than current smokers without job strain. In the analyses of longitudinal data (1 to 9 years of follow-up), there was no clear evidence for longitudinal associations between job strain and taking up or quitting smoking. CONCLUSIONS: Our findings show that smokers are slightly more likely than non-smokers to report work-related stress. In addition, smokers who reported work stress smoked, on average, slightly more cigarettes than stress-free smokers.

Long-term effects of biomechanical exposure on severe shoulder pain in the Gazel cohort.

OBJECTIVE: We aimed to assess whether the risk factors for severe shoulder pain, especially exposure to arm elevation, were still relevant after a 12-year follow-up, even following retirement. METHODS: All men participating in the ARPEGE ancillary study of the GAZEL cohort (followed-up since 1989) and who answered the 1994 or 1995 general GAZEL self-administered questionnaire were included. Weight and self-reported exposure (arm elevation >90° with and without carrying loads) over the entire working life were collected at baseline (1994-1995). Shoulder pain and its intensity were recorded in 1994-1995 and again in 2006. Shoulder pain was measured on an intensity or discomfort 6-point scale in 1994-1995 and on an 8-point scale in 2006. Severe shoulder pain was defined as point-rated higher than the mid-points (>3/6 in 1994-1995 and >4/8 in 2006) while moderate pain was lower or equal to these thresholds. RESULTS: At baseline, 1786 47-51-year-old men were included. In 1994-1995, moderate pain was observed among 8.5% (N=151) of men and severe shoulder pain among 14.6% (N=261). Exposure to arm elevation >90° while carrying loads was significantly associated with severe shoulder pain with >25 years of exposure [adjusted odds ratio (OR (adj)) 4.2, 95% confidence interval (95% CI) 1.7-10.5], taking into account age, sports, smoking habits, history of shoulder trauma, and body mass index. In 2006, when most of the subjects had retired, 1482 men (83.0%) answered the questionnaire, 17.3% of them with severe shoulder pain; the association between exposure to arm elevation >90° while carrying loads and severe shoulder pain was still significant (ORadj 3.3, 95% CI 1.3-8.0), and remained so when subjects with shoulder pain at baseline were excluded. CONCLUSIONS: Among men, the effect of high shoulder exposure (arm elevation >90° while carrying loads) during working life on severe shoulder pain remains even after retirement. Extended surveillance and prevention should be offered to these workers.

Post-retirement surveillance of workers exposed to asbestos or wood dust: first results of the French national SPIRALE Program.

OBJECTIVES: In France, 15 000-20 000 cancers attributable to occupational exposure occur each year. These cancers appear most often after the worker has retired. Since 1995, a system of post-retirement medical surveillance (PRMS) has been set up for former workers, but it remains largely underused. DESIGN: The SPIRALE program is a public health intervention aimed at identifying the former workers having been exposed to asbestos or wood dust during their working life and to propose them a PRMS. Additionally, it is also an epidemiologic research on the longterm effects of occupational exposure.We report the results of first years of the program conducted in 2006-2008, in 13 districts. SETTING AND PARTICIPANTS: a self-administered questionnaire was sent to 50 000 newly retired men, to identify potential past occupational carcinogen exposure. For respondents detected as possibly exposed, exposure was assessed in Health Screening Centres and a PRMS was recommended if necessary. MAIN OUTCOME MEASURES: Participation rate, rate of confirmed exposure, increased rate of PRMS, satisfaction about the program. RESULTS: The participation rate was 24%. From 12 002 questionnaires analysed, 72% of respondents were identified as possibly exposed: 3%to wood dust, 50%to asbestos and 19%to both exposures. Exposure to asbestos was confirmed for 73.4%, and according to the level of exposure, PRMS was recommended for 47.1%. Wood dust exposure was confirmed for 56.7%. In these districts, PRMS for asbestos increased by 45% and for wood dust by 600%. Additional surveys showed that participants showed a high degree of satisfaction about the program. CONCLUSIONS: The results are positive in terms of detection, information and medical surveillance of exposed workers.

Long-term effects of biomechanical exposure on severe knee pain in the Gazel cohort.

OBJECTIVE: Little is known about the long-term effect of occupational determinants on knee pain. We aimed to assess whether the risk factors for severe knee pain, observed with a cross-sectional approach, were still relevant after retirement, 12 years later. METHODS: All men participating in the ARPEGE side study of the GAZEL cohort (employees of the French national utility for energy production and distribution, recruited in 1989) and who answered the 1994 or 1995 general GAZEL self-administered questionnaire, were included. Weight and self-reported exposures over the entire working life were collected at baseline. Knee pain and its intensity were recorded in 1994-1995 and again in 2006. Moderate and severe knee pain, defined from an intensity or discomfort scale (threshold 3 on a 6-level scale in 1994-1995, and 4 on an 8-level scale in 2006), were the main outcomes. RESULTS: At baseline, 1786 men were included. In 1994-1995, moderate knee pain was observed among 10.3% and severe pain in 12.8% of men. In 2006, 1482 men (83%) answered the questionnaire. Moderate and severe knee pain were observed in 18.6% and 16.3% of respondents, respectively. Working in a kneeling or squatting position was significantly associated with severe knee pain at baseline, taking into account age, sports, smoking habits, and body mass index [adjusted odds ratio (OR (adj)) 1.4, 95% confidence interval (95% CI) 1.1-1.9 for "ever exposed" and OR (adj)2.0, 95% CI 1.3-3.1 for >25 years of exposure]. In 2006, when most subjects were retired, the association between working in a kneeling or squatting position and severe pain was weaker but still significant (OR (adj)1.4, 95% CI 1.04-1.85). CONCLUSIONS: The effect of high knee exposure in the working life on severe knee pain remains even after retirement, although decreased. An extended surveillance and prevention program for these workers could be proposed.