Associations between change in sleep duration and inflammation: findings on C-reactive protein and interleukin 6 in the Whitehall II Study

Cross-sectional evidence suggests associations between sleep duration and levels of the inflammatory markers, C-reactive protein and interleukin-6. This longitudinal study uses data from the London-based Whitehall II study to examine whether changes in sleep duration are associated with average levels of inflammation from 2 measures 5 years apart. Sleep duration (≤5, 6, 7, 8, ≥9 hours on an average week night) was assessed in 5,003 middle-aged women and men in 1991/1994 and 1997/1999. Fasting levels of C-reactive protein and interleukin-6 were measured in 1997/1999 and 2002/2004. Cross-sectional analyses indicated that shorter sleep is associated with higher levels of inflammatory markers. Longitudinal analyses showed that each hour per night decrease in sleep duration between 1991/1994 and 1997/1999 was associated with higher levels of C-reactive protein (8.1%) and interleukin-6 (4.5%) averaged across measures in 1997/1999 and 2002/2004. Adjustment for longstanding illness and major cardiometabolic risk factors indicated that disease processes may partially underlie these associations. An increase in sleep duration was not associated with average levels of inflammatory markers. These results suggest that both short sleep and reductions in sleep are associated with average levels of inflammation over a 5-year period.

Safety climate and verbal abuse among public hospital-based workers in Costa Rica

OBJECTIVE

Low levels of safety climate and training have been associated with higher occurrence of occupational-related health outcomes; workplace violence and verbal abuse could be considered an early indicator of escalating psychological workplace violence. We examined whether low level of safety factors were associated with a higher prevalence of verbal abuse at the workplace.

METHODS

We used data from a cross-sectional survey administered among a stratified random sample of 1,000 employees from 10 of the 29 public hospitals in Costa Rica. Odds ratios (OR) and 95% confidence intervals (95%CI) were calculated using survey logistic regression models to estimate the association between safety factors and verbal abuse from the following sources: administrators, supervisors, patients, patients' relatives and coworkers.

RESULTS

There was a high prevalence of verbal abuse among the healthcare workforce from both external (i.e., patients and patients' relatives) and internal workplace sources (i.e., coworkers, supervisors and administrators). A low level of safety climate was associated with verbal abuse from all sources with associations ranging from verbal abuse from administrators (OR=6.07; 95%CI: 2.05-17.92) to verbal abuse from patients (OR=2.24; 95%CI: 1.23-4.09).

CONCLUSION

These results highlight the need to address organizational characteristics of the workplace that may increase the risk of verbal abuse for the future development of prevention interventions in this setting.

The CUPID (Cultural and Psychosocial Influences on Disability) study: methods of data collection and characteristics of study sample

Background

The CUPID (Cultural and Psychosocial Influences on Disability) study was established to explore the hypothesis that common musculoskeletal disorders (MSDs) and associated disability are importantly influenced by culturally determined health beliefs and expectations. This paper describes the methods of data collection and various characteristics of the study sample.

Methods/Principal Findings

A standardised questionnaire covering musculoskeletal symptoms, disability and potential risk factors, was used to collect information from 47 samples of nurses, office workers, and other (mostly manual) workers in 18 countries from six continents. In addition, local investigators provided data on economic aspects of employment for each occupational group. Participation exceeded 80% in 33 of the 47 occupational groups, and after pre-specified exclusions, analysis was based on 12,426 subjects (92 to 1018 per occupational group). As expected, there was high usage of computer keyboards by office workers, while nurses had the highest prevalence of heavy manual lifting in all but one country. There was substantial heterogeneity between occupational groups in economic and psychosocial aspects of work; three- to five-fold variation in awareness of someone outside work with musculoskeletal pain; and more than ten-fold variation in the prevalence of adverse health beliefs about back and arm pain, and in awareness of terms such as “repetitive strain injury” (RSI).

Conclusions/Significance

The large differences in psychosocial risk factors (including knowledge and beliefs about MSDs) between occupational groups should allow the study hypothesis to be addressed effectively.

Contribution of volcanic ashes to the regional geochemical balance: the 2008 eruption of Chaitén volcano, Southern Chile

The environmental geochemical behaviour of the rhyolitic ashes from the 2008 eruption of Chaitén volcano, Southern Chile, has been studied. After the bulk characterisation, the potential contribution to the regional geochemical fluxes was examined using: i) single batch leaching tests to provide a rapid screening of the implied major and trace elements; and ii) column experiments to evaluate the temporal mobility of leached elements. The environmental concerns of these ashes are related to the fine grained component present in each sample (independent of distance from the source), in particular the presence of cristobalite, and the geochemical hazards posed by ash-water interaction. Leaching experiments show the fast dissolution of surface salts and aerosols, which dominate over glass dissolution during the first steps of the ash-water interaction. Chaitén ashes could transfer to the environment more than 1×10(10)g or 10,000 metric tonnes (mt) of Cl, S, Ca, Na, Si, and K; between 1000 and 10,000 mt of F, Mg, and Al; between 100 and 1000 mt of As, Pb, P, Fe, Sr, Zn, Mn, and Br; between 10 and 100 mt of Ba, Li, Ti, Ni, Nb, Cu, Rb, Zr, V, Mo, Co, and Sc; and less than 10 mt of Cr, Sb, Ce, Ga, Cs, and Y. These results show the fertilising potential of the ashes (e.g., providing Ca and Fe) but also the input of potentially toxic trace elements (e.g., F and As) in the regional geochemical mass balance. The Chaitén results evidence lower potentials for poisoning and fertilising than low silica ashes due to the lower contents released of practically all elements.

Return to work expectations of workers on long-term non-work-related sick leave

INTRODUCTION

Despite suggestions that worker perception might be the best predictor of return to work (RTW), there still is limited research on time to RTW in workers with lengthy non-work-related sick leave.

METHODS

Prospective cohort study of 663 workers with a current long-term non-work-related sick leave episode recruited during the first medical visit in a mutua (Spanish health insurance company) and followed until their sick leave episode ended. Workers completed a baseline questionnaire regarding their perceptions of sick leave episode and expectations of RTW (i.e., health status, work ability, expectations and time required to RTW, self-efficacy and self-perceived connection between health and job). Time to RTW was established based on the mutua's register. Cox regression models were used to examine the associations of worker perception and expectation of RTW with time to RTW within the study population as a whole as well as in three diagnostic subgroups (i.e., musculoskeletal disorders, mental disorders and other physical conditions).

RESULTS

As a whole, time to RTW was longer for workers reporting poor health [hazard ratio (HR) = 0.71, 95%CI 0.59-0.85], extremely reduced work ability (HR = 0.69, 95%CI 0.53-0.88), a longer period of time required to RTW (HR = 0.36, 95%CI 0.25-0.52) and lack of expectation of returning to the same job (HR = 0.13, 95%CI 0.06-0.31). Workers with musculoskeletal and other physical conditions showed a similar pattern to whole study population, while workers with mental disorders did not.

CONCLUSION

Self-required time and RTW expectations are important prognostic factors in sick listed workers by all types of health conditions certified as non-work-related. Questioning the workers on their perceptions and expectations of RTW during medical visits could help health care professionals to identify individuals at risk of long-term sickness absence and facilitate triage and management of the patient.

Mechanical systems versus smoking bans for secondhand smoke control

INTRODUCTION

Despite international efforts to implement smoking bans, several national legislations still allow smoking and recommend mechanical systems, such as ventilation and air extraction, to eliminate secondhand smoke (SHS) health-related risks. We aimed to quantify the relative contribution of mechanical systems and smoking bans to SHS elimination.

METHODS

A cross-sectional study was conducted in randomly selected establishments from 4 Mexican cities (3 with no ban). SHS exposure was assessed using nicotine passive monitors. Establishment characteristics, presence of mechanical systems, and enforcement of smoking policies were obtained through direct observation and self-report. Multilevel models were used to assess relative contributions to SHS reduction.

RESULTS

Compared with Mexico City, nicotine concentrations were 3.8 times higher in Colima, 5.4 in Cuernavaca, and 6.4 in Toluca. Mechanical systems were not associated with reduced nicotine concentrations. Concentration differences between cities were largely explained by the presence of smoking bans (69.1% difference reduction) but not by mechanical systems (-5.7% difference reduction).

CONCLUSIONS

Smoking bans represent the only effective approach to reduce SHS. Tobacco control regulations should stop considering mechanical systems as advisable means for SHS reduction and opt for complete smoking bans in public places.

Effect of working conditions on non-work-related sickness absence

BACKGROUND

There is limited evidence of the role of working conditions as prognostic factors for non-work-related sickness absence (i.e. absence due to injuries or diseases of non-occupational origin).

AIMS

To analyse the association between working conditions and time to return to work (RTW) in workers with long-term (>15 days) non-work-related sickness absence.

METHODS

We followed up a total of 655 workers, who completed a baseline questionnaire including physical and psychosocial work factors, until their non-work-related long-term sickness absence ended. Time to RTW was determined based on the health insurance company register. Cox proportional hazard models were constructed to evaluate the associations between working conditions and time to RTW.

RESULTS

A self-perceived high level of physical activity at work and work with back twisted or bent were related to longer duration of sickness absence. We did not find any strong evidence of associations between psychosocial work factors and time to RTW, although higher job insecurity and low reward showed marginal statistical significance.

CONCLUSIONS

Hazardous physical working conditions are associated with longer duration of non-work-related sickness absence. Workplace ergonomic interventions could conceivably shorten the length of sickness absence that has not originated at work.

Natural course of recurrent psychological distress in adulthood

BACKGROUND

The course of major depressive disorder is often characterized by progressing chronicity, but whether this applies to the course of self-reported psychological distress remains unclear. We examined whether the risk of self-reported psychological distress becomes progressively higher the longer the history of distress and whether prolonged history of distress modifies associations between risk markers and future distress.

METHODS

Participants were British civil servants from the prospective Whitehall II cohort study (n=7934; 31.5% women, mean age 44.5 years at baseline) followed from 1985 to 2006 with repeat data collected in 7 study phases. Psychological distress was assessed with the 30-item General Health Questionnaire (GHQ). Sex, socioeconomic status, marital status, ethnicity, physical activity, alcohol consumption, smoking, and obesity were assessed as risk markers.

RESULTS

Recurrent history of psychological distress was associated with a progressively increasing risk of future distress in a dose-response manner. Common risk markers, such as low socioeconomic status, non-White ethnicity, being single, and alcohol abstinence, were stronger predictors of subsequent distress in participants with a longer history of psychological distress. Sex differences in psychological distress attenuated with prolonged distress history.

LIMITATIONS

The participants were already adults in the beginning of the study, so we could not assess the progressive chronicity of psychological distress from adolescence onwards.

CONCLUSIONS

These data suggest that self-reported psychological distress becomes more persistent over time and that a longer prior exposure to psychological distress increases sensitivity to the stressful effects of certain risk markers.

Association of CRP and IL-6 with lung function in a middle-aged population initially free from self-reported respiratory problems: the Whitehall II study

To assess whether two inflammatory markers, C-reactive protein (CRP) and interleukin-6 (IL-6), and change in their concentrations over 12 years, are associated with lung function (FVC and FEV(1)) 12 years after baseline. Data are from over 1,500 participants free from self-reported respiratory problems in a large-scale prospective cohort study of white-collar male and female civil servants. CRP and IL-6 measured at baseline (1991-1993) and follow-up (2002-2004) and FVC and FEV(1), measured at follow-up. Results adjusted for sociodemographic and anthropometric characteristics, health behaviours, biological factors, chronic conditions and medications, and corrected for short-term variability in CRP and IL-6 concentrations. Higher baseline levels of CRP and IL-6 were strongly associated with lower FVC and FEV(1), independent of potential confounders. A 10% increase serum CRP from baseline to follow-up was associated with lower values of FVC and FEV(1) at follow-up, 4.7 and 3.0 ml, respectively. The corresponding values for a 10% increase in IL-6 were 12.6 ml for FVC and 7.3 ml for FEV(1). Systemic low-grade inflammation is associated with only slightly poorer pulmonary function in a population free from self-reported respiratory problems 12 years earlier. These data provide evidence linking inflammation to adverse outcomes beyond cardiovascular disease. Interventions targeting inflammation may prevent lung function impairment.

[Tobacco smoke exposure in public places in Mexico City, Guadalajara and Monterrey]

OBJECTIVE

To quantify environmental tobacco smoke exposure in public places in Mexico to promote policies of 100% smoke-free environments.

MATERIALS AND METHODS

In hospitals, schools and public offices of Monterrey, Guadalajara and Mexico City 20% of inner areas were monitored. Median nicotine concentrations were estimated by city, type of public space and type of inner area.

RESULTS

Median concentration in areas where nicotine was detected was 0.06 µg/m³ (P₂₅=0.03, P₇₅=0.12 µg/m³). Higher concentrations were found in Mexico City and in public offices. Nicotine was not detected in 75% of monitored areas.

CONCLUSIONS

Monitoring environmental nicotine is a useful tool to evaluate compliance of public places with the smoke-free environments legislation, and could constitute an important source of information to strengthen implementation efforts.

[Perception over smoke-free policies amongst bar and restaurant representatives in central Mexico]

OBJECTIVE

To analyze the perceptions and appreciations over smoke-free environments of restaurant and bar managers from four cities in central Mexico.

MATERIAL AND METHODS

Managers from 219 restaurants and bars from Mexico City, Colima, Cuernavaca and Toluca were surveyed about smoke-free environments opinions and implementation. Simultaneously, environmental nicotine was monitored.

RESULTS

The majority of surveyed managers considered public places should be smoke-free, although more than half were concerned with potential economic loses. Implementation of smoke-free environments was more frequent in Mexico City (85.4%) than in the other cities (15.3% overall), with consequently lower environmental nicotine concentrations.

CONCLUSION

Managers acknowledge the need to create smoke-free environments. Concerns over economic negative effects derived from the prohibition could explain, at least partially, the rejection of this sector towards the implementation of this type of policy.

Organisational justice and cognitive function in middle-aged employees: the Whitehall II study

BACKGROUND

Little is known about the role that work-related factors play in the decline of cognitive function. This study examined the association between perceived organisational justice and cognitive function among middle-aged men and women.

METHODS

Perceived organisational justice was measured at phases 1 (1985-8) and 2 (1989-90) of the Whitehall II study when the participants were 35-55 years old. Assessment of cognitive function at the screening clinic at phases 5 (1997-9) and 7 (2003-4) included the following tests in the screening clinic: memory, inductive reasoning (Alice Heim 4), vocabulary (Mill Hill), and verbal fluency (phonemic and semantic). Mean exposure to lower organisational justice at phases 1 and 2 in relation to cognitive function at phases 5 and 7 were analysed using linear regression analyses. The final sample included 4531 men and women.

RESULTS

Lower mean levels of justice at phases 1 and 2 were associated with worse cognitive function in terms of memory, inductive reasoning, vocabulary and verbal fluency at both phases 5 and 7. These associations were independent of covariates, such as age, occupational grade, behavioural risks, depression, hypertension and job strain.

CONCLUSIONS

This study suggests an association between perceived organisational justice and cognitive function. Further studies are needed to examine whether interventions designed to improve organisational justice would affect employees' cognition function favourably.

Environmental geochemistry of ancient volcanic ashes

Volcanic ashes from the Puna and surrounding Andean areas in northern Argentina show that sometimes volcanic ash deposits are very well preserved (up to several million years) and can remain a potential hazard for the environment in a similar way as current deposits. Eight ashes have been characterized by SEM-EDX and DRX, and their potential released geochemical fluxes were examined by using water and nitric acid batches, which are analyzed by ICP-OES, ICP-MS and ISE (F). Results demonstrate that water batch system is better medium than nitric acid for this study. The high and fast reactivity of these ancient ashes is mainly associated with their high content in glass. The order of magnitude of released contents of implied elements is consistent among the samples, i.e., Al>B>Fe>Zn>F>P>Mn>Ba>Sr>Li>Ti>Rb>Cu>Ni>Sb>Pb>As>Cr>V. Ash-water interaction, although infrequent in arid regions such as the Puna Region in northern Argentina, introduces rapid changes in the geochemical fluxes of elements and pH and may constitute a potential hazard for the environment. In fact, many of these elements are included in the drinking water guidelines due to their potential toxicity and may constitute potential hazards for the environment and human health.

Occupational safety and health interventions to reduce musculoskeletal symptoms in the health care sector

INTRODUCTION

Health care work is dangerous and multiple interventions have been tested to reduce the occupational hazards.

METHODS

A systematic review of the literature used a best evidence synthesis approach to address the general question "Do occupational safety and health interventions in health care settings have an effect on musculoskeletal health status?" This was followed by an evaluation of the effectiveness of specific interventions.

RESULTS

The initial search identified 8,465 articles, for the period 1980-2006, which were reduced to 16 studies based on content and quality. A moderate level of evidence was observed for the general question. Moderate evidence was observed for: (1) exercise interventions and (2) multi-component patient handling interventions. An updated search for the period 2006-2009 added three studies and a moderate level of evidence now indicates: (1) patient handling training alone and (2) cognitive behavior training alone have no effect on musculoskeletal health. Few high quality studies were found that examined the effects of interventions in health care settings on musculoskeletal health.

CONCLUSIONS

The findings here echo previous systematic reviews supporting exercise as providing positive health benefits and training alone as not being effective. Given the moderate level of evidence, exercise interventions and multi-component patient handling interventions (MCPHI) were recommended as practices to consider. A multi-component intervention includes a policy that defines an organizational commitment to reducing injuries associated with patient handling, purchase of appropriate lift or transfer equipment to reduce biomechanical hazards and a broad-based ergonomics training program that includes safe patient handling and/or equipment usage. The review demonstrates MCPHI can be evaluated if the term multi-component is clearly defined and consistently applied.

The association of cognitive performance with mental health and physical functioning strengthens with age: the Whitehall II cohort study

BACKGROUND

Cognitive performance has been associated with mental and physical health, but it is unknown whether the strength of these associations changes with ageing and with age-related social transitions, such as retirement. We examined whether cognitive performance predicted mental and physical health from midlife to early old age.

METHOD

Participants were 5414 men and 2278 women from the Whitehall II cohort study followed for 15 years between 1991 and 2006. The age range included over the follow-up was from 40 to 75 years. Mental health and physical functioning were measured six times using SF-36 subscales. Cognitive performance was assessed three times using five cognitive tests assessing verbal and numerical reasoning, verbal memory, and phonemic and semantic fluency. Socio-economic status (SES) and retirement were included as covariates.

RESULTS

High cognitive performance was associated with better mental health and physical functioning. Mental health differences associated with cognitive performance widened with age from 39 to 76 years of age, whereas physical functioning differences widened only between 39 and 60 years and not after 60 years of age. SES explained part of the widening differences in mental health and physical functioning before age 60. Cognitive performance was more strongly associated with mental health in retired than non-retired participants, which contributed to the widening differences after 60 years of age.

CONCLUSIONS

The strength of cognitive performance in predicting mental and physical health may increase from midlife to early old age, and these changes may be related to SES and age-related transitions, such as retirement.

Work disability following major organisational change: the Whitehall II study

BACKGROUND

Privatisation and private sector practices have been increasingly applied to the public sector in many industrialised countries. Over the same period, long-term work disability has risen substantially. We examined whether a major organisational change--the transfer of public sector work to executive agencies run on private sector lines--was associated with an increased risk of work disability.

METHODS

The study uses self-reported data from the prospective Whitehall II cohort study. Associations between transfer to an executive agency assessed at baseline (1991-1994) and work disability ascertained over a period of approximately 8 years at three follow-up surveys (1995-1996, 1997-1999 and 2001) were examined using Cox proportional hazard models.

RESULTS

In age- and sex-adjusted models, risk of work disability was higher among the 1263 employees who were transferred to an executive agency (HR 1.90, 95% CI 1.46 to 2.48) compared with the 3419 employees whose job was not transferred. These findings were robust to additional adjustment for physical and mental health and health behaviours at baseline.

CONCLUSIONS

Increased work disability was observed among employees exposed to the transfer of public sector work to executive agencies run on private sector lines. This may highlight an unintentional cost for employees, employers and society.

Physical and cognitive function in midlife: reciprocal effects? A 5-year follow-up of the Whitehall II study

BACKGROUND

Cognitive and physical functions are closely linked in old age, but less is known about this association in midlife. Whether cognitive function predicts physical function and whether physical function predicts cognitive function were assessed in middle-aged men and women.

METHODS

Data were from Whitehall II, an ongoing large-scale, prospective occupational cohort study of employees from 20 London-based white-collar Civil Service departments. The participants, 3446 men and 1274 women aged 45-68 years at baseline (1995-1997), had complete data on cognitive performance and physical function at both baseline and follow-up (2002-2004). A composite cognitive score was compiled from the following tests: verbal memory, inductive reasoning (Alice Heim 4-I), verbal meaning (Mill Hill), phonemic and semantic fluency. Physical function was measured using the physical composite score of the short form (SF-36) scale. Average follow-up was 5.4 years.

RESULTS

Poor baseline cognitive performance predicted poor physical function at follow-up (beta = 0.08, p<0.001), while baseline physical function did not predict cognitive performance (beta = 0.01, p = 0.67). After full adjustment for sociodemographic, behavioural and biological risk factors, baseline cognitive performance (beta = 0.04 p = 0.009) remained predictive of physical function.

CONCLUSION

Despite previous work indicating that the association between physical and cognitive performance may be bidirectional, these findings suggest that, in middle age, the direction of the association is predominantly from poor cognition to poor physical function.

Justice at work and metabolic syndrome: the Whitehall II study

OBJECTIVES

Growing evidence shows that high levels of justice are beneficial for employee health, although biological mechanisms underlying this association are yet to be clarified. We aim to test whether high justice at work protects against metabolic syndrome.

METHODS

A prospective cohort study of 20 civil service departments in London (the Whitehall II study) including 6123 male and female British civil servants aged 35-55 years without prevalent coronary heart disease at baseline (1985-1990). Perceived justice at work was determined by means of questionnaire on two occasions between 1985 and 1990. Follow-up for metabolic syndrome and its components occurring from 1990 to 2004 was based on clinical assessments on three occasions over more than 18 years.

RESULTS

Cox proportional hazard models adjusted for age, ethnicity and employment grade showed that men who experienced a high level of justice at work had a lower risk of incident metabolic syndrome than employees with a low level of justice (HR 0.75; 95% CI 0.63 to 0.89). There was little evidence of an association between organisational justice and metabolic syndrome or its components in women (HR 0.88; 95% CI 0.67 to 1.17).

CONCLUSIONS

Our prospective findings provide evidence of an association between high levels of justice at work and the development of metabolic syndrome in men.

Do pre-employment influences explain the association between psychosocial factors at work and coronary heart disease? The Whitehall II study

OBJECTIVES

To examine whether the association between psychosocial factors at work and incident coronary heart disease (CHD) is explained by pre-employment factors, such as family history of CHD, education, paternal education and social class, number of siblings and height.

METHODS

A prospective cohort study of 6435 British men aged 35-55 years at phase 1 (1985-1988) and free from prevalent CHD at phase 2 (1989-1990) was conducted. Psychosocial factors at work were assessed at phases 1 and 2 and mean scores across the two phases were used to determine long-term exposure. Selected pre-employment factors were assessed at phase 1. Follow-up for coronary death, first non-fatal myocardial infarction or definite angina between phase 2 and 1999 was based on clinical records (250 events, follow-up 8.7 years).

RESULTS

The selected pre-employment factors were associated with risk for CHD: HRs (95% CI) were 1.33 (1.03 to 1.73) for family history of CHD, 1.18 (1.05 to 1.32) for each quartile decrease in height and 1.16 (0.99 to 1.35) for each category increase in number of siblings. Psychosocial work factors also predicted CHD: 1.72 (1.08 to 2.74) for low job control and 1.72 (1.10 to 2.67) for low organisational justice. Adjustment for pre-employment factors changed these associations by 4.1% or less.

CONCLUSIONS

In this occupational cohort of British men, the association between psychosocial factors at work and CHD was largely independent of family history of CHD, education, paternal educational attainment and social class, number of siblings and height.