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.

Serum ω-3 Fatty Acids and Cognitive Domains in Community-Dwelling Older Adults from the NuAge Study: Exploring the Associations with Other Fatty Acids and Sex.

BACKGROUND: Omega-3 (n-3) PUFAs are suggested to play a role in the prevention of cognitive decline. The evidence may be inconsistent due to methodologic issues, including interrelations with other long-chain (14 or more carbons) fatty acids (LCFAs) and use of sex as a confounding factor rather than an effect modifier. OBJECTIVES: This study evaluated the association between serum n-3 PUFAs and performance across 4 cognitive domains, overall and by sex, while controlling for other LCFAs. METHODS: In total, 386 healthy older adults (aged 77.4 ± 3.8 y; 53% females) from the Quebec Longitudinal Study on Nutrition and Successful Aging underwent a cognitive evaluation and blood sampling. Verbal and nonverbal episodic memory, executive functioning, and processing speed were evaluated. Serum LCFA concentrations were measured by gas chromatography. LCFAs were grouped according to standard fatty acid classes and factor analysis using principal component analysis (FA-PCA). Multivariate linear regression models were performed, including unadjusted and adjusted models for other LCFAs. RESULTS: Higher n-3 PUFA concentrations were associated with better nonverbal memory and processing speed in fully adjusted models not including other LCFAs (ßs of 0.21 and 0.19, respectively). The magnitude of these associations varied when other LCFAs were entered in the model (ßs of 0.27 and 0.32, respectively) or when FA-PCA factors were considered (ßs of 0.27 and 0.21, respectively). Associations with verbal episodic memory were limited to higher concentrations of EPA, whereas there was no association between n-3 PUFAs and executive functioning. Higher n-3 PUFAs were associated with better verbal and nonverbal episodic memory in females and with better executive functioning and processing speed in males. CONCLUSIONS: These results suggest that other LCFAs should be considered when evaluating the association between n-3 PUFAs and cognitive performance in healthy older adults. Sex differences across cognitive domains warrant further investigation.

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.

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.

The impact of adjusting for pure predictors of exposure, mediator, and outcome on the variance of natural direct and indirect effect estimators.

It is now well established that adjusting for pure predictors of the outcome, in addition to confounders, allows unbiased estimation of the total exposure effect on an outcome with generally reduced standard errors (SEs). However, no analogous results have been derived for mediation analysis. Considering the simplest linear regression setting and the ordinary least square estimator, we obtained theoretical results showing that adjusting for pure predictors of the outcome, in addition to confounders, allows unbiased estimation of the natural indirect effect (NIE) and the natural direct effect (NDE) on the difference scale with reduced SEs. Adjusting for pure predictors of the mediator increases the SE of the NDE's estimator, but may increase or decrease the variance of the NIE's estimator. Adjusting for pure predictors of the exposure increases the variance of estimators of the NIE and NDE. Simulation studies were used to confirm and extend these results to the case where the mediator or the outcome is binary. Additional simulations were conducted to explore scenarios featuring an exposure-mediator interaction as well as the relative risk and odds ratio scales for the case of binary mediator and outcome. Both a regression approach and an inverse probability weighting approach were considered in the simulation study. A real-data illustration employing data from the Canadian Study of Health and Aging is provided. This analysis is concerned with the mediating effect of vitamin D in the effect of physical activity on dementia and its results are overall consistent with the theoretical and empirical findings.

Validity of participants' self-reported diagnosis for a work absence due to a mental health problem compared with physician-certified diagnosis for the same work absence among 709 Canadian workers.

OBJECTIVES: This study assesses the validity of a self-reported mental health problem (MHP) diagnosis as the reason for a work absence of 5 days or more compared with a physician-certified MHP diagnosis related to the same work absence. The potential modifying effect of absence duration on validity is also examined. METHODS: A total of 709 participants (1031 sickness absence episodes) were selected and interviewed. Total per cent agreement, Cohen's kappa, sensitivity and specificity values were calculated using the physician-certified MHP diagnosis related to a given work absence as the reference standard. Stratified analyses of total agreement, sensitivity and specificity values were also examined by duration of work absence (5-20 workdays,>20 workdays). RESULTS: Total agreement value for self-reported MHP was 90%. Cohen's kappa value was substantial (0.74). Sensitivity was 77% and specificity was 95%. Absences of more than 20 workdays had a better sensitivity than absences of shorter duration. A high specificity was observed for both short and longer absence episodes. CONCLUSION: This study showed high specificity and good sensitivity of self-reported MHP diagnosis compared with physician-certified MHP diagnosis for the same work absence. Absences of longer durations had a better sensitivity.

Psychosocial Stressors at Work and the Risk of Sickness Absence Due to a Diagnosed Mental Disorder: A Systematic Review and Meta-analysis.

Importance: Mental health problems are associated with considerable occupational, medical, social, and economic burdens. Psychosocial stressors at work have been associated with a higher risk of mental disorders, but the risk of sickness absence due to a diagnosed mental disorder, indicating a more severe condition, has never been investigated in a systematic review and meta-analysis. Objective: To synthesize the evidence of the association of psychosocial stressors at work with sickness absence due to a diagnosed mental disorder among adult workers. Data Sources: Seven electronic databases (MEDLINE, Embase, PsycInfo, Web of Science, CINAHL, Sociological Abstracts, and International Bibliography of the Social Sciences), 3 gray literature databases (Grey Literature Report, WHO-IRIS and Open Grey), and the reference lists of all eligible studies and reviews were searched in January 2017 and updated in February 2019. Study Selection: Only original prospective studies evaluating the association of at least 1 psychosocial stressor at work from the 3 most recognized theoretical models were eligible: the job demand-control-support model, including exposure to job strain (high psychological demands with low job control); effort-reward imbalance model; and organizational justice model. Study selection was performed in duplicate by blinded independent reviewers. Among the 28 467 citations screened, 23 studies were eligible for systematic review. Data Extraction and Synthesis: This meta-analysis followed the PRISMA and MOOSE guidelines. Data extraction and risk of bias evaluation, using the Risk of Bias in Nonrandomized Studies-Interventions tool, were performed in duplicate by blinded independent reviewers. Data were pooled using random-effect models. Main Outcomes and Measures: Sickness absence due to a mental disorder with a diagnosis obtained objectively. Results: A total of 13 studies representing 130 056 participants were included in the 6 meta-analyses. Workers exposed to low reward were associated with a higher risk of sickness absence due to a diagnosed mental disorder compared with nonexposed workers (pooled risk ratio [RR], 1.76 [95% CI, 1.49-2.08]), as were those exposed to effort-reward imbalance (pooled RR, 1.66 [95% CI, 1.37-2.00]), job strain (pooled RR, 1.47 [95% CI, 1.24-1.74]), low job control (pooled RR, 1.25 [95% CI, 1.02-1.53]), and high psychological demands (pooled RR, 1.23 [95% CI, 1.04-1.45]). Conclusions and Relevance: This meta-analysis found that workers exposed to psychosocial stressors at work were associated with a higher risk of sickness absence due to a mental disorder. A better understanding of the importance of these stressors could help physicians when evaluating their patients' mental health and work capacity.

Vitamin D status, cognitive decline and incident dementia: the Canadian Study of Health and Aging.

OBJECTIVE: Vitamin D could prevent cognitive decline because of its neuroprotective, anti-inflammatory and antioxidant properties. This study aimed to evaluate the associations of plasma 25-hydroxyvitamin D (25(OH)D) concentrations with global cognitive function and incident dementia, including Alzheimer's disease (AD). METHODS: The Canadian Study of Health and Aging is a 10-year cohort study of a representative sample of individuals aged 65 years or older. A total of 661 subjects initially without dementia with frozen blood samples and follow-up data were included. Global cognitive function was measured using the validated Modified Mini-Mental State (3MS) examination. A consensus diagnosis of all-cause dementia and AD was made between the physician and the neuropsychologist according to published criteria. Cognitive decline for a 5-year increase in age at specific 25(OH)D concentrations was obtained using linear mixed models with repeated measures. Hazard ratios of incident dementia and AD were obtained using semi-parametric proportional hazards models with age as time scale. RESULTS: Over a mean follow-up of 5.4 years, 141 subjects developed dementia of which 100 were AD. Overall, no significant association was found between 25(OH)D and cognitive decline, dementia or AD. Higher 25(OH)D concentrations were associated with an increased risk of dementia and AD in women, but not in men. CONCLUSION: This study does not support a protective effect of vitamin D status on cognitive function. Further research is needed to clarify the relation by sex.

Effect of psychosocial work factors on the risk of depression: a protocol of a systematic review and meta-analysis of prospective studies.

INTRODUCTION: Depression is a common and disabling health problem that contributes to an important social and economic burden, particularly among the working age population. The deleterious effect of psychosocial work factors on depression has been documented. However, the most recent systematic reviews had restrictive eligibility criteria and, since their publications, several original studies have been published. The proposed systematic review aims to update, evaluate and synthesise the effect of psychosocial work factors from three recognised theoretical models, the demand-control-support, effort-reward imbalance and organisational justice models, on the risk of depression among workers. METHOD AND ANALYSIS: A systematic literature search will be conducted in seven academic databases (Medline, Embase, CINAHL, Web of Science, PsycInfo, Sociological abstracts and IBSS) as well as three grey literature databases. The search strategy was first run on January 2017, updated in October 2017 and will be updated 6 months prior to submission for publication. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations, study selection will be carried out using a rigorous multistep screening process in duplicate by independent reviewers. Prospective studies evaluating the effect of at least one psychosocial work factor from the three theoretical models on depression or antidepressant medication use among working adults will be included. Extracted data will be used for evidence synthesis as well as to assess risk of bias and methodological quality. Meta-estimates will be provided after considering homogeneity and number of studies. ETHICS AND DISSEMINATION: This study will only draw from published studies and grey literature available in electronic databases; ethics approval is not required. The results of this review will be published in a peer review journal and presented at relevant conferences. Given that psychosocial work factors are frequent and modifiable, the results can help reduce the social and economic burden of depression and support public policy-makers to improve occupational health standards. PROSPERO REGISTRATION NUMBER: CRD42018107666.

Job strain and the prevalence of uncontrolled hypertension among white-collar workers.

To determine whether white-collar workers treated for hypertension who are exposed to psychosocial stressors at work have a higher prevalence of uncontrolled hypertension than unexposed workers, this study conducted three waves of data collection over a 5-year period (repeated cross-sectional design). The study sample was composed of 464 white-collar workers treated for hypertension. At each collection time, ambulatory blood pressure (ABP) was measured every 15 min during the workday. Uncontrolled hypertension was defined as a mean daytime systolic ABP ≥135 mmHg and/or diastolic ABP ≥85 mmHg for non-diabetic participants and systolic ABP ≥125 mmHg and/or diastolic ABP ≥75 mmHg for diabetic participants. Job strain was evaluated with Karasek's demand-latitude model using validated scales for psychological demands and decision latitude. Prevalence ratios (PR) and 95% confidence intervals (CI) were estimated using generalized estimating equations, adjusting for sociodemographic and lifestyle-related risk factors. Men with job strain (high demands and low latitude) and active jobs (high demands and high latitude) had a higher prevalence of uncontrolled hypertension (PR job strain = 1.46, 95% CI: 1.07-1.98 and PR active = 1.47, 95% CI: 1.12-1.94). When considered separately, high demands were associated with a higher prevalence of uncontrolled hypertension in both men (PR highest tertile = 1.60, 95% CI: 1.25-2.06) and women (PR highest tertile = 1.60, 95% CI: 1.03-2.47). Workers exposed to psychosocial stressors at work according to the demand-latitude model had a higher prevalence of uncontrolled hypertension. Reducing these frequent exposures could help to reduce the burden of uncontrolled hypertension.

Evaluation of the Quebec Healthy Enterprise Standard: Effect on Adverse Physical and Psychosocial Work Factors and Work-Related Musculoskeletal Problems.

OBJECTIVE: The aim of this study was to evaluate the effect of the Quebec Healthy Enterprise Standard (QHES) on adverse physical and psychosocial work factors and work-related musculoskeletal problems (WMSP). METHODS: Workers of 10 organizations completed questionnaires before (n = 2849) and 2 to 3 years following (n = 2560) QHES implementation. Outcomes were assessed using validated instruments. RESULTS: Workers exposed to adverse physical and psychosocial work factors had a higher prevalence of WMSP. After interventions, the prevalences of one adverse physical and three adverse psychosocial work factors were lower among workers exposed to interventions. Among men exposed to physical and psychosocial interventions, the lower prevalence of neck WMSP is compatible with a beneficial intervention effect. Other results generally showed few effects on WMSP. CONCLUSION: Results suggest that QHES implementation lead to a decrease in some adverse physical and psychosocial work factors. Few effects were observed on WMSP.

Masked hypertension incidence and risk factors in a prospective cohort study.

AIMS: Masked hypertension may affect up to 30% of the general population and is associated with a high cardiovascular disease risk. No previous study has examined the incidence of masked hypertension and its risk factors. The study aim was to determine the incidence of masked hypertension and to examine its related risk factors. METHODS: This is a cohort study including 1836 initially normotensive participants followed up on average for 2.9 years. Blood pressure was measured using Spacelabs 90207. Manual blood pressure was defined as the mean of the first three readings taken at rest. Ambulatory blood pressure was defined as the mean of the next readings recorded every 15 minutes during daytime working hours. Masked hypertension incidence at follow-up was defined as manual blood pressure less than 140 and less than 90 mmHg and ambulatory blood pressure at least 135 or at least 85 mmHg. Generalised estimating equations were used. RESULTS: The cumulative incidence of masked hypertension was 10.3% and was associated with male gender (relative risk (RR) 1.51, 95% confidence interval (CI) 1.18-1.94), older age (RR40-49 years 1.56, 95% CI 1.16-2.11, RR≥50 years 1.50, 95% CI 1.06-2.10), higher education (RRcollege 1.31, 95% CI 1.03-1.65), body mass index (RR≥27 1.43, 95% CI 1.11-1.85), smoking (RR 1.51, 95% CI 1.09-2.010) and alcohol intake (RR≥6/week 1.65, 95% CI 1.13-2.03). CONCLUSION: The present study is the first to identify risk factors for the incidence of masked hypertension. Current guidelines for hypertension detection recommend ambulatory blood pressure in patients with an elevated blood pressure reading at the clinic. As it is impractical to measure ambulatory blood pressure in all normotensive patients, factors identified in the present study should be considered for the screening of at-risk individuals and for primary prevention of masked hypertension.

Effect of psychosocial work factors on the risk of certified absences from work for a diagnosed mental health problem: a protocol of a systematic review and meta-analysis of prospective studies.

INTRODUCTION: Mental health problems (MHPs) are frequent and disabling and are the first or second leading cause of certified sickness absences from work in industrialised countries. They are generally long lasting and generate a considerable human and socioeconomic burden. The deleterious effect of adverse psychosocial work factors on MHP has been documented. However, the evidence regarding the effect of these factors on absences from work for an MHP has not been synthesised since 2007. The proposed systematic review aims to synthesise the effect of adverse psychosocial work factors from three validated theoretical models (the demand-control-support, effort-reward-imbalance and organisational justice models) on the risk of certified absences from work for diagnosed MHP among workers. METHOD AND ANALYSIS: A systematic search strategy will be conducted in seven databases: Medline, Embase, CINAHL, Web of Science, PsycInfo, Sociological abstracts and IBSS. Following Preferred Reporting Items for Systematic Reviews and Meta-Analyses recommendations, a multistep screening process by independent reviewers will lead to study selection. The search strategy was first run in 16 January 2017 and will be updated in October 2018. Only quantitative, prospective studies evaluating the effect of at least one psychosocial work factor from the validated theoretical models on certified absence from work for a diagnosed MHP will be considered for inclusion. Extracted data will be used for quantitative and qualitative evidence synthesis as well as to assess risk of bias and methodological quality. Meta-estimates will be provided for high-quality studies and by each psychosocial work factor, after considering homogeneity and number of studies. ETHICS AND DISSEMINATION: As this study will be based only on published studies, ethics approval is not required. Given that psychosocial works factors are frequent and modifiable, the results of this systematic review may provide evidence to support prevention strategies that can help to reduce the human social and economic burden associated with medically certified absences from work for an MHP. PROSPERO REGISTRATION NUMBER: CRD42018091632.

Evaluation of the Quebec Healthy Enterprise Standard: Effect on Adverse Psychosocial Work Factors and Psychological Distress.

Adverse psychosocial work factors are recognized as a significant source of psychological distress, resulting in a considerable socioeconomic burden. The impact of occupational health standards that aim to reduce these adverse work factors, such as the Quebec Healthy Enterprise Standard (QHES), is of great interest for public health. The aim of this study was to evaluate, for the first time, the effect of QHES interventions targeting adverse psychosocial work factors on the prevalence of these factors and of psychological distress among ten Quebec organizations. These outcomes were assessed by questionnaire using validated instruments before (T1, n = 2849) and 2-3 years following (T2, n = 2560) QHES implementation. Beneficial effects of interventions were observed for two adverse psychosocial work factors: low rewards (ratio of prevalence ratios (PRs) = 0.77, 95% CI = 0.66-0.91) and low social support at work (ratio of PRs = 0.89, 95% CI = 0.77-1.03). Moreover, beneficial effects of interventions were also observed on the prevalence of high psychological distress (ratio of PRs = 0.86, 95% CI = 0.75-0.998). Psychosocial interventions implemented in the context of this standard improved the psychosocial work environment and had beneficial effects on workers' mental health.

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.

Association between intake of sugar-sweetened beverages and circulating 25-hydroxyvitamin D concentration among premenopausal women.

Intake of sugar-sweetened beverages has increased in North America and seems to have several adverse health effects possibly through decreased circulating 25-hydroxyvitamin D (25(OH)D) concentrations. The aim of this cross-sectional study was to evaluate the association between sugar-sweetened beverages intake and 25(OH)D concentrations among premenopausal women. Intake of sugar-sweetened beverages including colas, other carbonated beverages and sweet fruit drinks was assessed using a validated food frequency questionnaire among 741 premenopausal women. Plasma concentrations of 25(OH)D were quantified by radioimmunoassay. The association between sugar-sweetened beverages intake and 25(OH)D concentrations was evaluated using multivariate generalized linear models and Spearman correlations. A higher intake of colas was associated with lower mean 25(OH)D levels (67.0, 63.7, 64.7 and 58.5 nmol/L for never, <1, 1-3 and >3 servings/week, respectively; r = -0.11 (p = 0.004)). A correlation was observed between intake of other carbonated beverages and 25(OH)D concentrations but was not statistically significant (r = -0.06 (p = 0.10)). No association was observed between intake of sweet fruit drinks and 25(OH)D concentrations. This study suggests that high intake of colas may decrease 25(OH)D levels in premenopausal women. Considering the high consumption of these drinks in the general population and the possible consequences of vitamin D deficiency on health, this finding needs further investigation.

Consumption of sweet foods and mammographic breast density: a cross-sectional study.

BACKGROUND: The increasing consumption of sugar worldwide seems to lead to several health problems, including some types of cancer. While some studies reported a positive association between sweet foods intake and breast cancer risk, little is known about their relation to mammographic density (MD), a strong breast cancer risk factor. This study examined the association of sweet foods and drinks intake with MD among 776 premenopausal and 779 postmenopausal women recruited at mammography. METHODS: A food-frequency questionnaire was used to assess intake of sweet foods, sugar-sweetened beverages and spoonsful of sugar added. Percent and absolute breast density were estimated using a computer-assisted method. Multivariate generalized linear models were used to evaluate associations. All models were adjusted for potential confounders, including age and body mass index. RESULTS: For increasing quartiles of sugar-sweetened beverages intake, adjusted-mean absolute density was respectively 32, 34, 32 and 36 cm2 among all women (P(trend) = 0.040) and 43, 46, 44 and 51 cm2 among premenopausal women (P(trend) = 0.007). For increasing quartiles of sweet foods intake, adjusted-mean percent density was respectively 16, 16, 17 and 19% among postmenopausal women (P(trend) = 0.036). No association was shown between intake of spoonsful of sugar added and MD. CONCLUSION: Our results suggest that an increase in sweet foods or sugar-sweetened beverage intake is associated with higher MD.