Organisational justice and markers of inflammation: the Whitehall II study

OBJECTIVES

Low organisational justice has been shown to be associated with increased risk of various health problems, but the underlying mechanisms remain unclear. We tested whether organisational injustice contributes to chronic inflammation in a population of middle-aged men and women.

METHODS

This prospective cohort study uses data from 3205 men and 1204 women aged 35-55 years at entry into the Whitehall II study (phase 1, 1985-1988). Organisational justice perceptions were assessed at phase 1 and phase 2 (1989-1990) and circulating inflammatory markers C-reactive protein (CRP) and interleukin (IL)-6 at phase 3 (1991-1993) and phase 7 (2003-2004).

RESULTS

In men, low organisational justice was associated with increased CRP levels at both follow-ups (phase 3 and 7) and increased IL-6 at the second follow-up (phase 7). The long term (phase 7) associations were largely independent of covariates, such as age, employment grade, body mass index and depressive symptoms. In women, no relationship was found between organisational justice and CRP or IL-6.

CONCLUSIONS

This study suggests that organisational injustice is associated with increased long-term levels of inflammatory markers among men.

Obesity, unexplained weight loss and suicide: the original Whitehall study

BACKGROUND

Evidence on the association between obesity and suicide is mixed. However, the strength of obesity as a predictor of suicide may be reduced, because of the role of weight changes associated with mental disorders. We tested the hypothesis that both obesity and unexplained weight loss are related to elevated suicide risk.

METHODS

A clinical examination with measurements of height, weight and self-reported unexplained weight loss was conducted at baseline for 18,784 men aged 40 to 69. Based on national mortality register data, 61 suicides were identified during the 38-year follow-up.

RESULTS

The age-adjusted hazard ratio for suicide among obese versus normal weight men was 2.22 (95% CI 0.94 to 5.28). Additional adjustment for unexplained weight loss raised this ratio to 2.48 (95% CI 1.04 to 5.92). Unexplained weight loss was associated with a substantial excess risk of suicide irrespective of obesity (age-adjusted hazard ratio 5.38, 95% CI 2.31 to 12.50; age- and obesity-adjusted hazard ratio 5.58, 95% CI 2.37 to 13.13).

LIMITATIONS

Inability to take into account the effect of depression as a potential mediating mechanism.

CONCLUSIONS

This study provides evidence that both obesity and unexplained weight loss may be important predictors of suicide. Lack of adjustment for weight loss may suppress the observed association between obesity and suicide.

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.

Association between passive jobs and low levels of leisure-time physical activity: the Whitehall II cohort study

BACKGROUND

There is mixed evidence on the association between psychosocial work exposures (ie, passive jobs) and physical activity, but previous studies did not take into account the effect of cumulative exposures nor did they examine different trajectories in exposure. We investigated whether exposure to passive jobs, measured three times over an average of 5 years, is associated with leisure-time physical activity (LTPA).

METHODS

Data were from working men (n = 4291) and women (n = 1794) aged 35-55 years who participated in the first three phases of the Whitehall II prospective cohort. Exposure to passive jobs was measured at each phase and LTPA at phases 1 and 3. Participants were categorised according to whether or not they worked in a passive job at each phase, leading to a scale ranging from 0 (non-passive job at all three phases) to 3 (passive job at all three phases). Poisson regression with robust variance estimates were used to assess the prevalence ratios of low LTPA.

RESULTS

An association was found in men between exposure to passive jobs over 5 years and low LTPA at follow-up, independently of other relevant risk factors. The prevalence ratio for low LTPA in men was 1.16 (95% CI 1.01 to 1.33) times greater for employees with three reports of passive job than for those who had never worked in passive jobs. No association was observed in women.

CONCLUSION

This study provides evidence that working in passive jobs may encourage a passive lifestyle in men.

Long working hours and sleep disturbances: the Whitehall II prospective cohort study

STUDY OBJECTIVE

To examine whether exposure to long working hours predicts various forms of sleep disturbance; short sleep, difficulty falling asleep, frequent waking, early waking and waking without feeling refreshed.

DESIGN

Prospective study with 2 measurements of working hours (phase 3, 1991-1994 and phase 5, 1997-1999) and 2 measurements of subjective sleep disturbances (phase 5 and phase 7, 2002-2004).

SETTING

The Whitehall II study of British civil servants.

PARTICIPANTS

Full time workers free of sleep disturbances at phase 5 and employed at phases 5 and 7 (n = 937-1594) or at phases 3, 5, and 7 (n = 886-1510).

MEASUREMENTS AND RESULTS

Working more than 55 hours a week, compared with working 35-40 hours a week, was related to incident sleep disturbances; demographics-adjusted odds ratio (95% CI) 1.98 (1.05, 3.76) for shortened sleeping hours, 3.68 (1.58, 8.58) for difficulty falling asleep; and 1.98 (1.04, 3.77) for waking without feeling refreshed. Repeat exposure to long working hours was associated with odds ratio 3.24 (1.45, 7.27) for shortened sleep, 6.66 (2.64, 16.83) for difficulty falling asleep, and 2.23 (1.16, 4.31) for early morning awakenings. Some associations were attenuated after adjustment for other risk factors. To a great extent, similar results were obtained using working hours as a continuous variable. Imputation of missing values supported the findings on shortened sleep and difficulty in falling asleep.

CONCLUSION

Working long hours appears to be a risk factor for the development of shortened sleeping hours and difficulty falling asleep.

Non-response to baseline, non-response to follow-up and mortality in the Whitehall II cohort

BACKGROUND

Little is known about the associations between non-response to follow-up surveys and mortality, or differences in these associations by socioeconomic position in studies with repeat data collections.

METHODS

The Whitehall II study of socioeconomic inequalities in health provided response status from five data collection surveys; Phase 1 (1985-88, n = 10 308), Phase 5 (1997-99, n = 6533), and all-cause mortality to 2006. Odd-numbered phases included a medical examination in addition to a questionnaire.

RESULTS

Non-response to baseline and to follow-up phases that included a medical examination was associated with a doubling of the mortality hazard in analyses adjusted for age and sex. Compared with complete responders, responders who missed one or more phases, but completed the last possible phase before they died, had a 38% excess risk of mortality. However, those who missed one or more phases including the last possible phase before death had an excess risk of 127%. There was no evidence that these associations differed by socioeconomic position.

CONCLUSION

In studies with repeat data collections, non-response to follow-up is associated with the same doubling of the mortality risk as non-response to baseline; an association that is not modified by socioeconomic position.

Occupational exposures and asthma in health-care workers: comparison of self-reports with a workplace-specific job exposure matrix

The authors compared self-reported occupational exposures with a workplace-specific job exposure matrix (JEM) in a 2004 survey of Texas health-care professionals (n = 3,650), by asthma status. Sensitivity, specificity, chance-corrected (kappa) and chance-independent (phi) agreement, and associations of self-reported exposures with asthma were compared with those for the JEM. Among asthmatics, the median sensitivity of self-reported exposures was 74% (range, 53-90); specificity was 64% (range, 27-74). For nonasthmatics, median sensitivity was 67% (range, 40-88) and specificity was 70% (range, 33-82). Sensitivity was higher among asthmatics for exposures involving perceptible odors. Specificity was higher among nonasthmatics for instrument cleaning and exposure to adhesives/solvents. Asthmatics showed better agreement with the JEM for patient-care-related cleaning (phi = 0.51 vs. 0.40); there was little difference for other exposures. In all cases, confidence intervals overlapped. Prevalence ratios were higher with self-reported exposures than with the JEM; differences were greatest for cleaning products, adhesives/solvents, and gases/vapors. However, confidence intervals overlapped with those obtained using the JEM. In asthma studies, differential reporting bias by health status should be taken into consideration. Findings favor using externally developed methods of exposure classification, although information gleaned from examining distributions of exposure self-reports, particularly among nondiseased persons, can provide useful information for improving the reliability of exposure ascertainment.

Long working hours and cognitive function: the Whitehall II Study

This study examined the association between long working hours and cognitive function in middle age. Data were collected in 1997-1999 (baseline) and 2002-2004 (follow-up) from a prospective study of 2,214 British civil servants who were in full-time employment at baseline and had data on cognitive tests and covariates. A battery of cognitive tests (short-term memory, Alice Heim 4-I, Mill Hill vocabulary, phonemic fluency, and semantic fluency) were measured at baseline and at follow-up. Compared with working 40 hours per week at most, working more than 55 hours per week was associated with lower scores in the vocabulary test at both baseline and follow-up. Long working hours also predicted decline in performance on the reasoning test (Alice Heim 4-I). Similar results were obtained by using working hours as a continuous variable; the associations between working hours and cognitive function were robust to adjustments for several potential confounding factors including age, sex, marital status, education, occupation, income, physical diseases, psychosocial factors, sleep disturbances, and health risk behaviors. This study shows that long working hours may have a negative effect on cognitive performance in middle age.

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.

Socioeconomic position, psychosocial work environment and cerebrovascular disease among women: the Finnish public sector study

BACKGROUND

The excess risk of fatal and non-fatal cerebrovascular disease in people from low socioeconomic positions is only partially explained by conventional cerebrovascular risk factors. This has led to the suggestion that poor psychosocial work environments provide important additional explanatory power. However, little evidence is available for women.

METHODS

We examined whether job demands or job control contributed to the socioeconomic gradient in cerebrovascular disease among 48 361 women aged 18-65 years. Job demands, job control and behavioural risk factors were self-reported in 2000-2002; socioeconomic position (as indexed by occupational class) and all of the health measures were obtained from registers. The outcome was recorded hospitalization or death from cerebrovascular disease.

RESULTS

During a mean follow-up of 3.4 years, 124 women had a new cerebrovascular disease event. The risk was 2.3 (95% CI 1.3-3.9) times higher among women in low vs high socioeconomic positions. Adjustment for conventional risk factors, such as prevalent hypertension, coronary heart disease, diabetes, smoking, heavy alcohol consumption, physical inactivity and obesity, attenuated this excess risk by 23%. In contrast, adjustment for job demands and job control actually amplified the gradient by 36% suggesting a suppression effect.

CONCLUSIONS

In this contemporary cohort of employed women, job demands-alone and in combination with job control-suppressed rather than explained socioeconomic differences in cerebrovascular disease.

Inflammatory markers and cognitive function in middle-aged adults: the Whitehall II study

OBJECTIVES

To assess whether C-reactive protein (CRP) and interleukin-6 (IL-6) are associated with low cognitive performance and decline in middle-aged adults.

DESIGN/SETTING

The Whitehall II study; an ongoing large-scale, prospective occupational cohort study of employees from 20 London-based white-collar Civil Service departments.

PARTICIPANTS

Data from more than 3000 males and 1200 female employees.

MEASURES

Inflammatory makers measured in 1991-1993 and five cognitive tests (short-term verbal memory, inductive reasoning (AH4-I), vocabulary (Mill Hill), and phonemic and semantic fluency) performed in 1997-1999 and 2002-2004. Performance in the lowest sex-specific quintile indicated low cognitive performance or decline. Covariates included sociodemographics, health behaviours and health conditions.

RESULTS

In age-adjusted analyses both CRP and IL-6 were associated with all cognitive measures in 1997-1999, even though the association with memory was not consistent. After extensive adjustment raised CRP levels were only associated with poor cognitive performance on the AH4-I (OR=1.38; 95% CI: 1.05-1.82) and Mill Hill (OR=1.52; 95% CI: 1.14-2.03) and IL-6 on semantic fluency (OR=1.27; 95% CI: 1.14-2.03). Associations were more evident in men than in women. No clear relationship was observed for decline.

CONCLUSIONS

Our results suggest that raised levels of inflammatory markers in midlife are moderately associated with lower cognitive status, but little with cognitive decline.

Neighbourhood characteristics and trajectories of health functioning: a multilevel prospective analysis

BACKGROUND

Prospective data from over 10 years of follow-up were used to examine neighbourhood deprivation, social fragmentation and trajectories of health.

METHODS

From the third phase (1991-93) of the Whitehall II study of British civil servants, SF-36 health functioning was measured on up to five occasions for 7834 participants living in 2046 census wards. Multilevel linear regression models assessed the Townsend deprivation index and social fragmentation index as predictors of initial health and health trajectories.

RESULTS

Independent of individual socioeconomic factors, deprivation was inversely associated with initial SF-36 physical component summary (PCS) score. Social fragmentation was not associated with PCS scores. Deprivation and social fragmentation were inversely associated with initial mental component summary (MCS) score. Neighbourhood characteristics were not associated with trajectories of PCS score or MCS score for the whole set. However, restricted analysis on longer term residents revealed that residents in deprived or socially fragmented neighbourhoods had lowest initial and smallest improvements in MCS score.

CONCLUSIONS

This longitudinal study provides evidence that residence in a deprived or fragmented neighbourhood is associated with poorer mental health and that longer exposure to such neighbourhood environments has incremental effects. Associations between physical health functioning and neighbourhood characteristics were less clear. Mindful of the importance of individual socioeconomic factors, the findings warrant more detailed examination of materially and socially deprived neighbourhoods and their consequences for health.

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.

Does return to work occur earlier after work-related sick leave episodes than after non-work-related sick leave episodes? A retrospective cohort study in Spain

OBJECTIVE

In Spain, sick pay benefits for work-related sick leave episodes are higher than for non-work-related episodes. Our aim is to assess whether time to return to work is longer for higher paid sick leave episodes than for lower paid episodes.

METHODS

We used data from 62,376 work-related and 76,932 non-work-related sick leave episodes occurring among 338,226 workers from 56,099 companies in Spain in 2002. All episodes were followed for up to 18 months. Episodes were classified by a physician as being work- or non-work-related according to medico-legal judgments. The median episode duration and the 25th and 75th percentiles were calculated. The probability of remaining absent from work was estimated by a non-parametric estimator of the marginal survival function. The time ratio between both types of sick leave was estimated by a log-logistic regression model, using non-work-related episodes as the reference.

RESULTS

Median episode duration (25th-75th percentiles) was 11 (6-21) days for work-related episodes and 9 (4-29) days for non-work-related episodes. Time to return to work was longer for work-related episodes than for non-work-related episodes of less than 16 days (time ratio: 1.19 in men and 1.08 in women), while the opposite was observed for episodes of more than 15 days (0.58 in men and 0.40 in women).

CONCLUSIONS

Sick pay benefits have a limited effect on time to return to work after a sick leave episode.

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 < or =4 words) and decline (decrease of > or =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 (> or =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.

Work organization and drinking: an epidemiological comparison of two psychosocial work exposure models

OBJECTIVES

To examine the relationship between two alternative psychosocial work exposure measurement frameworks (i.e., job alienation and job stress) and three drinking behaviours (frequent, heavy and drinking and work).

METHODS

A cross-sectional survey was conducted among 3,099 US drinking workers. Job stress conditions were assessed according to the Karasek's job strain model. Alienating job conditions were assessed with measures based on Kohn and Schooler's occupational self-direction concept. Multivariate logistic regression controlling for a wide range of known covariates was used.

RESULTS

High strain work showed no associations, while workers in passive jobs had an increased likelihood of heavy (OR = 1.29; 95%CI: 1.02-1.64) and lower likelihood of frequent drinking (OR = 0.71; 95%CI: 0.52-0.97). Unexpectedly, low complexity combined with low constraint related to more frequent drinking (OR = 1.60; 95%CI: 1.22-2.10). No associations with drinking at work were observed.

CONCLUSION

Our findings suggest an association between different work environment features and drinking behaviours. Our findings highlight the value of exploring the hypothesized passive pathway of the job strain model together with other theoretical perspectives, such as alienating job conditions.

Do psychological factors affect inflammation and incident coronary heart disease: the Whitehall II Study

OBJECTIVE

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.

When do social inequalities in C-reactive protein start? A life course perspective from conception to adulthood in the Cardiovascular Risk in Young Finns Study

BACKGROUND

It is unclear when in the life course do social inequalities in inflammation emerge. We examined whether the association between socioeconomic position (SEP) and C-reactive protein (CRP) is determined at conception, in childhood, adolescence or adulthood in 1484 participants from the population-based Cardiovascular Risk in Young Finns Study.

METHODS

Five variants of the CRP gene were used to investigate whether SEP differences in CRP levels are determined at conception. SEP and serum CRP were assessed in childhood (age 3-9), adolescence (age 12-18) and in adulthood (age 24-39). SEP was measured using parental education and occupational status in childhood and adolescence, and participants' own education and occupational status in adulthood. Participants with CRP > 10 mg/l were excluded.

RESULTS

All CRP gene variants were associated with circulating CRP concentrations in childhood, but there were no differences in the distribution of these variants by SEP. No strong evidence was found of associations between parental SEP and CRP. A graded association between higher SEP and lower CRP was observed in adulthood for education (P = 0.0005) but not for occupational status. Trajectories that led to high educational achievement both in the participants and their parents were associated with lower (P <or= 0.047) CRP levels in adulthood. Excluding participants with infectious diseases, pregnant or lactating women and women using oral contraceptives did not change the findings.

CONCLUSION

In this cohort, SEP differences in CRP concentrations seen in adulthood appear not to be determined at conception or evident in childhood or adolescence.

[Return to work after a non-work related sick spell: the role of age, sex, economic activity and autonomous community]

BACKGROUND

To describe the duration of non-work related sickness absences incidents according to age, sex, economic activity and Autonomous Community.

METHODS

The sample of non-work related sick spells included 76,598 incident cases started in 2002 among workers cover by the general regime of the Social Security system, and managed by an insurance company. The median and intercuartils range were estimated by sex, age, economic activities and Autonomous Comunnity. Probability ratio of continuing out of work (PRCOW) were compared among Autonomous Comunities, after adjusting by sexo, age and economic activities, taking Navarra as reference, using a log-logistic regression model with a gamma distribution.

RESULTS

The 25% of cases there were returned to work at 40 day, the 50% at 90 day; and the 75% at 26 degrees day. Extremadura (PCOW=2,7; IC95%: 2,4-3,1) and Galicia (2,6; 2,4-2,9) showed the highest differences with Navarra. There were also statistically significant differences among economic activities after adjusting by age and sex.

CONCLUSIONS

Return to work after a non-work related sick spell is a complex process, which is influenced by age, sex, economic activities and autonomous community.

Association of occupation and safety practices with work-injury absence among public hospital employees in Latin America: a study from Costa Rica

BACKGROUND

Injury-related statistics in developing countries are rare.

OBJECTIVE

To assess the relationship between occupational and safety-related risk factors and absences from work during the preceding 6 months due to work-related injury among public hospital employees in Costa Rica.

METHODS

Data were used from a cross-sectional survey conducted in December 2000 among a stratified random sample of 1000 employees from 10 of the 29 public hospitals in Costa Rica. The questionnaire included sociodemographic data, occupational exposures, and organizational risk factors. A dichotomous variable was created to indicate work-injury absence. At-risk employees (n = 466) were classified as having had a work-injury absence if they reported having been absent for at least 1 day in the preceding 6 months because of a work-related injury. OR and 95% CI were calculated using unconditional logistic regression models.

RESULTS

There is a greater likelihood of injury-related absence in non-professional occupational positions (ie, auxiliary personnel (OR = 2.29) and general services employees (OR = 5.55)) than in professional positions, and in employees who show poor compliance with safety practices (OR = 2.03) and have high interference from their job task (OR = 3.79) compared with their counterparts.

CONCLUSIONS

Work-injury absence appears not only to be a function of work injury, but also a function of occupation and degree of compliance with safety practices.