David Gimeno

Associations of C-reactive protein and interleukin-6 with cognitive symptoms of depression: 12-year follow-up of the Whitehall II study.

BACKGROUND A lack of longitudinal studies has made it difficult to establish the direction of associations between circulating concentrations of low-grade chronic inflammatory markers, such as C-reactive protein and interleukin-6, and cognitive symptoms of depression. The present study sought to assess whether C-reactive protein and interleukin-6 predict cognitive symptoms of depression or whether these symptoms predict inflammatory markers. METHOD In a prospective occupational cohort study of British white-collar civil servants (the Whitehall II study), serum C-reactive protein, interleukin-6 and cognitive symptoms of depression were measured at baseline in 1991-1993 and at follow-up in 2002-2004, an average follow-up of 11.8 years. Symptoms of depression were measured with four items describing cognitive symptoms of depression from the General Health Questionnaire. The number of participants varied between 3339 and 3070 (mean age 50 years, 30% women) depending on the analysis. RESULTS Baseline C-reactive protein (beta=0.046, p=0.004) and interleukin-6 (beta=0.046, p=0.005) predicted cognitive symptoms of depression at follow-up, while baseline symptoms of depression did not predict inflammatory markers at follow-up. After full adjustment for sociodemographic, behavioural and biological risk factors, health conditions, medication use and baseline cognitive systems of depression, baseline C-reactive protein (beta=0.038, p=0.036) and interleukin-6 (beta=0.041, p=0.018) remained predictive of cognitive symptoms of depression at follow-up. CONCLUSIONS These findings suggest that inflammation precedes depression at least with regard to the cognitive symptoms of depression.

Job strain as a predictor of disability pension: the Finnish Public Sector Study

Objective: To examine whether high job strain (a combination of high job demands and low job control) is a risk factor for disability pension. Setting: Ten municipalities and 21 hospitals in Finland. Design and participants: A prospective cohort study of 20 386 female and 4 764 male Finnish public sector employees aged 19–50 using data from two surveys (baseline in 2000–2 and follow-up in 2005) and employers’ registers. In addition to self-reported job strain, we computed work unit-aggregated job strain for each participant (the average of scores of all workers of participant’s work unit except the participant him/herself). Main results: 93 employees (0.4%) retired because of disability during the follow-up. In multilevel logistic regression analysis adjusted for demographic characteristics and health risk behaviour, odds for disability pension was 2.60 (95% CI 1.26 to 5.34) times higher for employees with high self-assessed job strain than for those with low self-assessed job strain at baseline. The corresponding OR for passive job versus low job strain was 2.82 (95% CI 1.34 to 5.96). Analysis of work unit-aggregated scores replicated the association for high job strain, OR 2.25 (95% CI 1.17 to 4.35), but not that for passive job. The association between work unit job strain and disability pension remained significant after further adjustment for prevalent diseases, psychological distress and perceived health status. Conclusions: Job strain is associated with risk of subsequent disability pension. If causal, this association suggests that organisational interventions to reduce job strain may also reduce early exit from work.

Low HDL Cholesterol Is a Risk Factor for Deficit and Decline in Memory in Midlife The Whitehall II Study

Objective—The purpose of this study was to examine the relationship between fasting serum lipids and short-term verbal memory in middle-aged adults. Methods and Results—Total cholesterol, high-density lipoprotein cholesterol (HDL-C), triglycerides, and memory were measured twice, at mean ages 55 and 61, in 3673 male and female participants of the Whitehall II study. Short-term verbal memory was assessed using a 20-word list. Logistic regression was used to model associations between ATP-III categories of lipids and memory deficit (recall of ≤4 words) and decline (decrease of ≥2 words). Analyses were adjusted for education, occupational position, coronary heart disease, stroke, hypertension, use of medication, diabetes, smoking, and alcohol consumption. Compared to high HDL-C (≥60 mg/dL), low HDL-C (<40 mg/dL) was associated with greater odds of memory deficit at the first (OR=1.27; 95% confidence interval [CI]=0.91 to 1.77) and second wave of this study (OR=1.53; 95% CI=1.04 to 2.25) in fully adjusted analysis. Decrease in HDL-C over the 5-year follow-up period was associated with decline in memory in the adjusted analysis (OR=1.61; 95% CI=1.19 to 2.16); no interaction with APOE e4 status was present. Conclusions—HDL-C levels are potentially modifiable, and our results suggest that low HDL-C is associated with poor memory and decline in memory in middle-aged adults.

Do Psychological Factors Affect Inflammation and Incident Coronary Heart Disease. The Whitehall II Study

Objectives—The purpose of this study was to test whether psychological factors affect inflammation processes to an extent that increases the risk of coronary heart disease (CHD). Methods and Results—We used data from 6396 civil servants (4453 men, 1943 women) from the Whitehall II Study, aged 35 to 55 years and free from clinically validated CHD at the start of the follow-up period. Two psychological factors were assessed at phase 1 (1985 to 1988) and phase 2 (1989 to 1990): negative affect and psychological distress. Inflammatory biomarkers (fibrinogen, high-sensitivity C-reactive- protein, interleukin-6) and 12 baseline covariates including biological and behavioral CHD risk factors, sociodemographic variables, and work stress were measured at phase 3 (1991 to 1993). Follow-up for CHD death, first nonfatal myocardial infarction, or definite angina occurring between phase 3 and phase 7 (2003 to 2004) was based on clinical records. Higher levels of inflammatory markers were associated with higher CHD incidence, with hazard ratios (HR) ranging from 1.31 to 2.37 in age-and sex-adjusted models. Higher levels of negative affectivity and psychological distress were not associated with greater concentrations of inflammatory markers. Negative affectivity (relative index of inequality=1.68, 95% confidence interval [CI] 1.20 to 2.36) and higher psychological distress exposure (HR=1.66, 95% CI 1.28 to 2.14) were associated with higher CHD incidence and these associations remained unchanged after adjustment for inflammatory markers. Conclusions—Our findings suggest that psychological factors do not affect inflammation although they predict incident CHD.

Social Inequality in Walking Speed in Early Old Age in the Whitehall II Study

BACKGROUND We investigated social inequalities in walking speed in early old age. METHODS Walking speed was measured by timed 8-ft (2.44 m) test in 6,345 individuals, with mean age of 61.1 (SD 6.0) years. Current or last known civil service employment grade defined socioeconomic position. RESULTS Mean walking speed was 1.36 (SD 0.29) m/s in men and 1.21 (SD 0.30) in women. Average age- and ethnicity-adjusted walking speed was approximately 13% higher in the highest employment grade compared with the lowest. Based on the relative index of inequality (RII), the difference in walking speed across the social hierarchy was 0.15 m/s (95% confidence interval [CI] 0.12-0.18) in men and 0.17 m/s (0.12-0.22) in women, corresponding to an age-related difference of 18.7 (13.6-23.8) years in men and 14.9 (9.9-19.9) years in women. The RII for slow walking speed (logistic model for lowest sex-specific quartile vs others) adjusted for age, sex, and ethnicity was 3.40 (2.64-4.36). Explanatory factors for the social gradient in walking speed included Short-Form 36 physical functioning, labor market status, financial insecurity, height, and body mass index. Demographic, psychosocial, behavioral, biologic, and health factors in combination accounted for 40% of social inequality in walking speed. CONCLUSION Social inequality in walking speed is substantial in early old age and reflects many factors beyond the direct effects of physical health.

The role of job strain on return to work after carpal tunnel surgery

Aims: To examine the impact of job strain (that is, high psychological job demands and low job control) on return to work and work role functioning at two months, six months, or both, following carpal tunnel release surgery. Methods: A community based cohort of carpal tunnel syndrome (CTS) patients from physician practices was recruited between April 1997 and October 1998 throughout Maine (USA). 128 patients at two months and 122 at six months completed all relevant questions. A three level outcome variable indicated whether patients had: (1) returned to work functioning successfully, (2) returned to work functioning with limitations, or (3) not returned to work for health reasons. Two job strain measures were created: one, by combining psychological job demands and job control; and two, by dividing demands by control. Ordinal logistic regression was used to identify predictors of the three level work outcome variable. Results: After adjustment, workers with high demands and high control (active work) were less likely to successfully return to work (OR = 0.22; p = 0.014) at two months. Having a job with higher demands than job control (high strain) predicted not returning to work or returning to work but not successfully meeting job demands (OR = 0.14; p = 0.001), at six months. Conclusions: The findings underscore the role of psychosocial work conditions, as defined by the Karasek demand-control model, in explaining a worker’s return to work. Clinicians, researchers, and employers should consider a multidimensional and integrative model of successful work role functioning upon return to work. Moreover, since the evidence of the effects of work process changes on the reduction of CTS is very scarce, these findings point to the opportunity for collaborative workplace interventions to facilitate successful return to work.

Do psychological attributes matter for adherence to antihypertensive medication? The Finnish Public Sector Cohort Study

Objective Psychological factors may be important determinants of adherence to antihypertensive medication, as they have been repeatedly found to be associated with an increased risk of hypertension, coronary heart disease, and health-damaging behaviours. We examined the importance of several psychological attributes (sense of coherence, optimism, pessimism, hostility, anxiety) with regard to antihypertensive medication adherence assessed by pharmacy refill records. Methods A total of 1021 hypertensive participants, aged 26–63 years, who were employees in eight towns and 12 hospitals in Finland were included in the analyses. Results We found 60% of patients to be totally adherent, 36% partially adherent, and 4% totally nonadherent. Multinomial regression analyses revealed high sense of coherence to be associated with lower odds of being totally nonadherent in contrast of being totally adherent (odds ratio = 0.55; 95% confidence interval: 0.31–0.96). This association was independent of factors that influenced adherence to antihypertensive medication, such as sociodemographic characteristics, health-related behaviours, self-reported medical history of doctor-diagnosed comorbidity, and anteriority of hypertension status. The association was not specific to certain types of antihypertensive drugs. Conclusion High sense of coherence may influence antihypertensive medication-adherence behaviour. Aspects characterizing this psychological attribute, such as knowledge (comprehensibility), capacity (manageability), and motivation (meaningfulness) may be important determinants of adherence behaviour for asymptomatic illnesses, such as hypertension, in which patients often do not feel or perceive the immediate consequences of skipping medication doses.

A glossary for the social epidemiology of work organisation: Part 3, Terms from the sociology of labour markets

This is part 3 of a three-part glossary on the social epidemiology of work organisation. The first two parts deal with the social psychology of work and with organisations.1,2 This concluding part presents concepts related to labour markets. These concepts are drawn from economics, business and sociology. They relate both to traditional interests in these disciplines and to contemporary ideas on post-industrialisation and globalisation,3 particularly the growth of employment in service industries, the development of a 24-h economy, increased participation of the female labour force and the perceived needs of employers in emerging high-tech economies.4,5 These changes are of particular interest because they are linked to increasing inequality in earnings and changes in social relationships in employment.6 These concepts have the potential to elucidate the pathways through which health is affected by conditions of work as an underlying cause.7,8 Contingent employment refers to work with unpredictable hours or of limited duration.9,10 Work may be unpredictable because jobs are structured to be of short term or temporary, or because the hours vary in unpredictable ways. The US Bureau of Labour Statistics has adopted the first part of this definition, short-term or temporary work contracts, as its definition of contingent employment, and has considered the second part, unpredictably variable hours, as an alternative employment arrangement, a strategy for increasing the flexibility of work assignments.11 Workers are in contingent employment when they are working on limited-duration contracts, working through temporary work agencies or on call. One form of particular interest is the development of firms specialising in the placement of temporary workers. This industry has grown dramatically in recent years and was a substantial proportion of job growth in the US in the 1990s.12 Some self-employed workers may be considered to …

Organisational and occupational risk factors associated with work related injuries among public hospital employees in Costa Rica

Aims: To explore the relation between occupational and organisational factors and work related injuries (WRI) among public hospital employees in Costa Rica. Methods: A cross-sectional survey was conducted among a stratified random sample of 1000 employees from 10 of the 29 public hospitals in Costa Rica. A previously validated, self-administered questionnaire which included occupational and organisational factors and sociodemographic variables was used. From the final eligible sample (n = 859), a total of 842 (response rate 98%) questionnaires were returned; 475 workers were analysed after excluding not-at-risk workers and incomplete questionnaires. WRI were computed for the past six months. Results: Workers exposed to chemicals (RR = 1.36) and physical hazards (RR = 1.26) had higher WRI rate ratios than non-exposed workers. Employees reporting job tasks that interfered with safety practices (RR = 1.46), and a lack of safety training (RR = 1.41) had higher WRI rate ratios than their counterparts. Low levels of safety climate (RR = 1.51) and safety practices (RR = 1.27) were individually associated with an increased risk of WRI. Also, when evaluated jointly, low levels of both safety climate and safety practices showed the highest association with WRI (RR = 1.92). Conclusions: When evaluated independently, most of the occupational exposures and organisational factors investigated were significantly correlated with an increased injury risk. As expected, some of these associations disappeared when evaluated jointly. Exposure to chemical and physical hazards, lack of safety training, and low levels of safety climate and safety practices remained significant risk factors for WRI. These results will be important to consider in developing future prevention interventions in this setting.

Cumulative exposure to high-strain and active jobs as predictors of cognitive function: the Whitehall II study

Objectives: A high-strain job (a combination of high job demands and low job control) is expected to increase the risk of health problems, whereas an active job (high demands and high control) can be hypothesised to be associated with a greater capacity to learn. We tested associations between high-strain and active jobs and cognitive function in middle-aged men and women. Methods: Data on 4146 British civil servants (2989 men and 1157 women) aged 35–55 years at baseline came from the Whitehall II study. Cumulative exposure to both high-strain and active jobs was assessed at phases 1 (1985–1988), 2 (1989–1990) and 3 (1991–1993). Cognitive performance was assessed at phases 5 (1997–1999) and 7 (2003–2004) using the following tests: verbal memory, inductive reasoning (Alice Heim), verbal meaning (Mill Hill), phonemic and semantic fluency. Analyses were adjusted for age, sex and employment grade. Results: Longer exposure to high job strain and shorter exposure to active jobs were associated with lower scores in most of the cognitive performance tests. However, these associations disappeared on adjustment for employment grade. Phonemic fluency was an exception to this pattern. Associations between exposure to an active job and phonemic fluency at both follow-up phases were robust to adjustment for employment grade. However, there was no association between exposure to active jobs and change in phonemic fluency score between the follow-up phases after adjustment for employment grade. Conclusions: In these data, associations between cumulative exposure to high-strain or active jobs and cognition are largely explained by socioeconomic position.