Objective:

To examine the association of body mass index (BMI) and metabolic status with cognitive function and decline.

Methods:

A total of 6,401 adults (71.2% men), aged 39–63 years in 1991–1993, provided data on BMI (normal weight 18.5–24.9 kg/m2, overweight 25–29.9 kg/m2; and obese ≥30 kg/m2) and metabolic status (abnormality defined as 2 or more of 1) triglycerides ≥1.69 mmol/L or lipid-lowering drugs, 2) systolic blood pressure ≥130 mm Hg, diastolic blood pressure ≥85 mm Hg, or antihypertensive drugs, 3) glucose ≥5.6 mmol/L or medications for diabetes, and 4) high-density lipoprotein cholesterol <1.04 mmol/L for men and <1.29 mmol/L for women). Four cognitive tests (memory, reasoning, semantic, and phonemic fluency) were administered in 1997–1999, 2002–2004, and 2007–2009, standardized to z scores, and averaged to yield a global score.

Results:

Of the participants, 31.0% had metabolic abnormalities, 52.7% were normal weight, 38.2% were overweight, and 9.1% were obese. Among the obese, the global cognitive score at baseline (p = 0.82) and decline (p = 0.19) over 10 years was similar in the metabolically normal and abnormal groups. In the metabolically normal group, the 10-year decline in the global cognitive score was similar (p for trend = 0.36) in the normal weight (−0.40; 95% confidence interval [CI] −0.42 to −0.38), overweight (−0.42; 95% CI −0.45 to −0.39), and obese (−0.42; 95% CI −0.50 to −0.34) groups. However, in the metabolically abnormal group, the decline on the global score was faster among obese (−0.49; 95% CI −0.55 to −0.42) than among normal weight individuals (−0.42; 95% CI −0.50 to −0.34), (p = 0.03).

Conclusions:

In these analyses the fastest cognitive decline was observed in those with both obesity and metabolic abnormality.

Backround

This study examined whether asthma alone or together with chronic co-morbidity is associated with increased risk of long-term work disability.

Methods

We examined data from 2,332 asthmatic and 66,354 non-asthmatic public sector employees in Finland who responded to a survey between 1997 and 2004. Respondents were coded as persistent asthmatics based on the special reimbursement for continuous asthma medication by the Social Insurance Institution. Data on long-term work disability (sickness absences or disability pensions >90 days) were obtained from national registers. The risk of work disability was examined by Cox proportional hazard models adjusted for age, gender, socioeconomic status, type of employment contract and type of employer.

Results

Asthma increased the risk of all-cause long-term work disability, hazard ratio (HR) 1.8 (95 % CI 1.62–2.09) compared to controls (no asthma). Asthma and one other chronic co-morbidity increased the risk for long-term all-cause work disability with HR 2.2 (95% CI 1.78–2.83). Asthma together with two or more other chronic conditions increased the risk with HR 4.5 (95% CI 2.98–6.78). Asthma and depression increased the risk with HR 3.6 and the risk was especially high for permanent work-disability (HR 6.8). Among those with asthma there were more women, obesity (BMI ≥30), ex-smokers and lower-grade non-manual workers.

Conclusions

Asthma is associated with increased risk of long-term all-cause work disability. The risk increases further with chronic co-morbidities, and is especially high in patients with asthma and depression.

In genetics, major progress was made after pooling of data sets to mega-studies became the norm in the field. In the present commentary, the authors ask whether such an approach would also be worthy of broader application in the field of social epidemiology. Research on job strain and coronary heart disease provides an illustrative example. Over 3 decades, debate has continued as to the relative importance of high psychological demands versus low control—that is, whether one component of job strain is more toxic than the other—and differences by age and sex. Recently, these controversies were largely resolved in an individual-participant meta-analysis of 200,000 participants from 13 cohorts: The combination of both high demands and low control was a greater risk factor than either of the components alone, there were no differences in the associations of job strain with CHD between men and women, between the young and old, or at different levels of socioeconomic position, and the impact was more modest when unpublished data were included but was still robust to all adjustments. The fact that longstanding debates in the job strain literature were resolved by applying an individual-participant data meta-analysis approach suggests that lessons learned in genetics might also apply to social epidemiology.

Background

Concern has been recently raised about possible adverse cardio-metabolic effects of high selenium status, such as increased risks of diabetes and hyperlipidemia. However, most of the evidence comes from selenium-replete populations such as the US.

Objectives

To examine cross-sectional and longitudinal associations of serum selenium with cardiovascular risk factors in Finland where selenium levels were among the lowest in the world until the early 1980s before the implementation of a nationwide selenium fertilization program.

Methods

Serum selenium was measured in 1,235 young Finns aged 3-18 years at baseline in 1980 (pre-fertilization), and in a subgroup (N=262) at the 6-year follow-up (1986, post-fertilization). During the 27-year follow-up, serum lipids, blood pressure, BMI, and smoking were assessed five times (1980, 1983, 1986, 2001, and 2007).

Results

Mean (±SD) serum selenium concentrations were 74.3±14.0 ng/mL in 1980 and 106.6±12.5 ng/mL in 1986 (average increase 32.3 ng/mL; 95% CI: 30.3 to 34.3, p<0.0001). In univariate and multivariable cross-sectional models in 1980 and 1986, increased serum selenium levels were consistently associated with increased total, HDL- and LDL-cholesterol. However, the average longitudinal changes in lipids were −0.20 mmol/L (95% CI: −0.30 to −0.10, p<0.0001) for total cholesterol, 0.06 mmol/L (95% CI: 0.03 to 0.10, p<0.0001) for HDL-cholesterol, and −0.23 mmol/L (95% CI: −0.31 to −0.14, p<0.0001) for LDL-cholesterol. Selenium measured in 1986 was not associated with lipids assessed in 2001 and 2007.

Conclusions

Cross-sectional findings from the Young Finns study corroborate positive associations of selenium status with serum lipids. However, longitudinal evidence does not support the causality of this link.

Objectives

Childhood adversities may be important determinants of later illnesses and poor health behaviour. However, large-scale prospective studies on the associations between childhood adversities and the onset of asthma in adulthood are lacking.

Design

Prospective cohort study with 7-year follow-up.

Setting

Nationally representative study. Data were collected from the Health and Social Support (HeSSup) survey and national registers.

Participants

The participants represent the Finnish population from the following age groups: 20–24, 30–34, 40–44, and 50–54 years at baseline in 1998 (24 057 survey participants formed the final cohort of this study). The occurrence of childhood adversities was assessed at baseline with a six-item survey scale. The analyses were adjusted for sociodemographic characteristics, behavioural health risks and common mental disorders.

Primary and secondary outcomes

The survey data were linked to data from national health registers on incident asthma during a 7-year follow-up to define new-onset asthma cases with verified diagnoses.

Results

A total of 12 126 (59%) participants reported that they encountered a childhood adversity. Of them 3677 (18% of all) endured three to six adversities. During a follow-up of 7 years, 593 (2.9%) participants were diagnosed with incident asthma. Those who reported three or more childhood adversities had a 1.6-fold (95% CI 1.31 to 2.01) greater risk of asthma compared to those without childhood adversities. This hazard attenuated but remained statistically significant after adjustment for conventional risk factors (HR 1.33; 95% CI 1.06 to 1.67).

Conclusions

Adults who report having encountered adversities in childhood may have an increased risk of developing asthma.

Objectives

Although sickness absence is a strong predictor of health, little work has examined whether this association varies by occupational position. The aim of this study was to investigate overall and diagnosis-specific sickness absence as a predictor of future long-term sub-optimal health by occupational position.

Methods

Prospective occupational cohort study; 15,320 employees (73% men) aged 37–51. Sickness absences (1990–1992), including 13 diagnostic categories, were examined by occupational position, based on employment grade, in relation to self-rated health measured annually 1993–2006.

Results

60% of employees in higher grade and 22% in lower grade occupations had no sickness absence. Conversely, 40% of employees in lower grade and 9.5% in higher grade occupations had over 30 sick-leave days. Repeated-measures logistic regression analyses adjusted for age, sex, and chronic disease showed employees with over 30 days absence, compared to those with no absence, had approximately double the risk of suboptimal health over the 14-year follow-up in all occupational positions. However, 1–30 days sick-leave was associated with greater odds of suboptimal health in the high; odds ratio 1.48, 95% confidence intervals (1.27–1.72) and intermediate 1.29 (1.15–1.45), but not lower grade occupations 1.06 (0.82–1.38). Differences by occupational position in the association between sickness absence in 13 specific diagnostic categories and sub-optimal health over the ensuing 14 years were limited to stronger associations observed with cancer and mental disorders in the higher grades.

Conclusions

The association between sickness absence of over 30 days a year and future long-term self-rated health appears to differ little by occupational position.

Background: Associations between traffic noise and sleep problems have been detected in experimental studies, but population-level evidence is scarce.

Objectives: We studied the relationship between the levels of nighttime traffic noise and sleep disturbances and identified vulnerable population groups.

Methods: Noise levels of nighttime–outdoor traffic were modeled based on the traffic intensities in the cities of Helsinki and Vantaa, Finland. In these cities, 7,019 public sector employees (81% women) responded to postal surveys on sleep and health. We linked modeled outdoor noise levels to the residences of the employees who responded to the postal survey. We used logistic regression models to estimate associations of noise levels with subjectively assessed duration of sleep and symptoms of insomnia (i.e., difficulties falling asleep, waking up frequently during the night, waking up too early in the morning, nonrestorative sleep). We also used stratified models to investigate the possibility of vulnerable subgroups.

Results: For the total study population, exposure to levels of nighttime–outside (Lnight, outside) traffic noise > 55 dB was associated with any insomnia symptom ≥ 2 nights per week [odds ratio (OR) = 1.32; 95% confidence interval (CI): 1.05, 1.65]. Among participants with higher trait anxiety scores, which we hypothesized were a proxy for noise sensitivity, the ORs for any insomnia symptom at exposures to Lnight, outside traffic noises 50.1–55 dB and > 55 dB versus ≤ 45 dB were 1.34 (95% CI: 1.00, 1.80) and 1.61 (95% CI: 1.07, 2.42), respectively.

Conclusions: Nighttime traffic noise levels > 50 dB Lnight, outside was associated with insomnia symptoms among persons with higher scores for trait anxiety. For the total study population, Lnight, outside > 55 dB was positively associated with any symptoms.

Summary

Background

Published work assessing psychosocial stress (job strain) as a risk factor for coronary heart disease is inconsistent and subject to publication bias and reverse causation bias. We analysed the relation between job strain and coronary heart disease with a meta-analysis of published and unpublished studies.

Methods

We used individual records from 13 European cohort studies (1985–2006) of men and women without coronary heart disease who were employed at time of baseline assessment. We measured job strain with questions from validated job-content and demand-control questionnaires. We extracted data in two stages such that acquisition and harmonisation of job strain measure and covariables occurred before linkage to records for coronary heart disease. We defined incident coronary heart disease as the first non-fatal myocardial infarction or coronary death.

Findings

30 214 (15%) of 197 473 participants reported job strain. In 1·49 million person-years at risk (mean follow-up 7·5 years [SD 1·7]), we recorded 2358 events of incident coronary heart disease. After adjustment for sex and age, the hazard ratio for job strain versus no job strain was 1·23 (95% CI 1·10–1·37). This effect estimate was higher in published (1·43, 1·15–1·77) than unpublished (1·16, 1·02–1·32) studies. Hazard ratios were likewise raised in analyses addressing reverse causality by exclusion of events of coronary heart disease that occurred in the first 3 years (1·31, 1·15–1·48) and 5 years (1·30, 1·13–1·50) of follow-up. We noted an association between job strain and coronary heart disease for sex, age groups, socioeconomic strata, and region, and after adjustments for socioeconomic status, and lifestyle and conventional risk factors. The population attributable risk for job strain was 3·4%.

Interpretation

Our findings suggest that prevention of workplace stress might decrease disease incidence; however, this strategy would have a much smaller effect than would tackling of standard risk factors, such as smoking.

Funding

Finnish Work Environment Fund, the Academy of Finland, the Swedish Research Council for Working Life and Social Research, the German Social Accident Insurance, the Danish National Research Centre for the Working Environment, the BUPA Foundation, the Ministry of Social Affairs and Employment, the Medical Research Council, the Wellcome Trust, and the US National Institutes of Health.

Objectives

Although sickness absence is a strong predictor of health, little work has examined whether this association varies by occupational position. The aim of this study was to investigate overall and diagnosis-specific sickness absence as a predictor of future long-term sub-optimal health by occupational position.

Methods

Prospective occupational cohort study; 15,320 employees (73% men) aged 37–51. Sickness absences (1990–1992), including 13 diagnostic categories, were examined by occupational position, in relation to self-rated health measured annually 1993–2006.

Results

60% of employees in higher occupational position and 22% in lower position had no sickness absence. Conversely, 9.5% of employees in higher position and 40% in lower occupational position had over 30 sick-leave days. Repeated-measures logistic regression analyses adjusted for age, sex, and chronic disease showed employees with over 30 days absence, compared to those with no absence, had approximately double the risk of suboptimal health over the 14-year follow-up in all occupational positions. However, 1–30 days sick-leave was associated with greater odds of suboptimal health in the high; odds ratio 1.48, 95% confidence intervals (1.27–1.72) and intermediate 1.29 (1.15–1.45), but not lower occupational positions 1.06 (0.82–1.38). Differences by occupational position in the association between sickness absence in 13 specific diagnostic categories and sub-optimal health over the ensuing 14 years were limited to stronger associations observed with cancer and mental disorders in the higher occupational positions.

Conclusions

The association between sickness absence of over 30 days a year and future long-term self-rated health appears to differ little by occupational position.

Background

Shift-working nurses are exposed to a stressful work environment, which puts them at an increased risk for burnout and depression. We explored the effect of environmental stress on serotonin transporter gene (SLC6A4) promoter methylation among nurses from high and low work stress environments.

Methodology

Using bisulfite sequencing, we investigated the methylation status of five CpG residues of a CpG-rich region in the promoter of SLC6A4 by comparing female shift working nurses from a high work stress environment (n = 24) to low work stress environment (n = 25). We also analyzed the association of 5-HTTLPR polymorphism at 5′ end of SLC6A4. Work stress was assessed by the Karasek’s Model and possible signs of burnout or depression were measured by the Maslach Burnout Index General Survey and Beck Depression Index. Methylation levels were assessed by bisulfite sequencing of DNA extracted from peripheral blood leucocytes. Restriction enzyme treatment followed by standard PCR was used to identify 5-HTTLPR genotypes.

Principal Findings

We found that nurses in the high stress environment had significantly lower promoter methylation levels at all five CpG residues compared to nurses in the low stress environment (p<0.01). There was no significant interaction of 5-HTTLPR genotype and work stress with methylation (p = 0.58). In unadjusted (bivariate) analysis, burnout was not significantly associated to methylation levels. However, when mutually adjusted for both, burnout and work stress were significant contributors (p = 0.038 and p<0.0001 respectively) to methylation levels.

Conclusions

Our findings show that environmental stress is concurrent with decreased methylation of the SLC6A4 promoter. This may lead to increased transcriptional activity of the gene, increased reuptake of serotonin from synaptic clefts, and termination of the activity of serotonin. This could present a possible coping mechanism for environmental stress in humans that could eventually increase risk for disturbed functional capability and experience of depressed mood in long-term stress.

Background

Cardiovascular risk factors and diseases are important aetiological factors in depression, particularly late-life depression. Brain changes associated with vascular disease and depression can be detected using magnetic resonance imaging. Using diffusion tensor imaging (DTI), we investigated whether the Framingham stroke risk profile (FSRP), a well validated risk prediction algorithm, is associated with changes in white-matter connectivity. We hypothesised that depressed participants would show reduced white-matter integrity with higher FSRP, and non-depressed controls (matched for mean vascular risk) would show minimal co-variance with white-matter changes.

Methods

36 participants with major depression (age 71.8±7.7 years, mean FSRP 10.3±7.6) and 25 controls (age 71.8±7.3 years, mean FSRP 10.1±7.7) were clinically interviewed and examined, followed by 60-direction DTI on a 3.0 Tesla scanner. Image analysis was performed using FSL tools (www.fmrib.ox.ac.uk/fsl) to assess the correlation between FSRP and fractional anisotropy (FA). Voxelwise statistical analysis of the FA data was carried out using Tract Based Spatial Statistics. The significance threshold for correlations was set at p<0.05 using threshold-free cluster-enhancement. Partial correlation analysis investigated significant correlations in each group.

Results

Participants in the depressed group showed highly significant correlations between FSRP and FA within: body of corpus callosum (r=−0.520, p=0.002), genu of corpus callosum (r= −0.468, p=0.005), splenium of corpus callosum (r=−0.536, p=0.001) and corticospinal tract (r=−0.473, p=0.005). In controls, there was only one significant correlation in the body of corpus callosum (r=−0.473, p=0.023).

Conclusions

FSRP is associated with impairment in white-matter integrity in participants with depression; these results suggest support for the vascular depression hypothesis.

Background

Poor indoor air quality (IAQ) and psychosocial problems are common in schools worldwide, yet longitudinal research on the issue is scarce. We examined whether the level of or a change in pupil-reported school environment (IAQ, school satisfaction, and bullying) predicts recorded sick leaves among teachers.

Methods

Changes in the school environment were assessed using pupil surveys at two time points (2001/02 and 2004/05) in 92 secondary schools in Finland. Variables indicating change were based on median values at baseline. We linked these data to individual-level records of teachers’ (n = 1678) sick leaves in 2001–02 and in 2004–05.

Results

Multilevel multinomial logistic regression models adjusted for baseline sick leave and covariates showed a decreased risk for short-term (one to three days) sick leaves among teachers working in schools with good perceived IAQ at both times (OR = 0.6, 95% CI: 0.5-0.9), and for those with a positive change in IAQ (OR = 0.6, 95% CI: 0.4-0.9), compared to teachers in schools where IAQ was constantly poor. Negative changes in pupil school satisfaction (OR = 1.8, 95% CI: 1.1-2.8) and bullying (OR = 1.5, 95% CI: 1.0-2.3) increased the risk for short-term leaves among teachers when compared to teachers in schools where the level of satisfaction and bullying had remained stable. School environment factors were not associated with long-term sick leaves.

Conclusions

Good and improved IAQ are associated with decreased teacher absenteeism. While pupil-related psychosocial factors also contribute to sick leaves, no effect modification or mediation of psychosocial factors on the association between IAQ and sick leave was observed.

The authors aggregated the results of observational studies examining the association between long working hours and coronary heart disease (CHD). Data sources used were MEDLINE (through January 19, 2011) and Web of Science (through March 14, 2011). Two investigators independently extracted results from eligible studies. Heterogeneity between the studies was assessed using the I2 statistic, and the possibility of publication bias was assessed using the funnel plot and Egger's test for small-study effects. Twelve studies were identified (7 case-control, 4 prospective, and 1 cross-sectional). For a total of 22,518 participants (2,313 CHD cases), the minimally adjusted relative risk of CHD for long working hours was 1.80 (95% confidence interval (CI): 1.42, 2.29), and in the maximally (multivariate-) adjusted analysis the relative risk was 1.59 (95% CI: 1.23, 2.07). The 4 prospective studies produced a relative risk of 1.39 (95% CI: 1.12, 1.72), while the corresponding relative risk in the 7 case-control studies was 2.43 (95% CI: 1.81, 3.26). Little evidence of publication bias but relatively large heterogeneity was observed. Studies varied in size, design, measurement of exposure and outcome, and adjustments. In conclusion, results from prospective observational studies suggest an approximately 40% excess risk of CHD in employees working long hours.

Objective

To examine the association between workplace social capital and all-cause mortality in a large occupational cohort from Finland.

Methods

Responses of 28,043 participants to surveys in 2000–2002 and 2004 were linked to national mortality registers through 2009. We used repeated measurements of self-assessed and co-workers' assessed workplace social capital. Cox proportional hazard and fixed effects logistic regressions were conducted.

Results

196 employees died during the 5-year follow-up period. A one unit increase in the mean of repeat measurements of self-assessed workplace social capital (range 1–5) was associated with a 19% decrease in the risk of all-cause mortality [age- and sex-adjusted HR=0.81; 95% CI 0.66–0.99]. The corresponding point estimate for the mean of co-workers' assessed social capital was similar, although the association was more imprecisely estimated [age- and sex-adjusted HR=0.77; 95% CI 0.50–1.20]. In fixed-effects analysis, a one unit increase in self-assessed social capital across the two time points was associated with a lower mortality risk (OR=0.81, 95% CI 0.55–1.19).

Conclusion

These findings suggest that workplace social capital is associated with decreased risk of mortality in the working-age population.

Objective

To examine the combined effects of depressive symptoms and resting heart rate (RHR) on mortality.

Methods

Data come from 5936 participants, aged 61 ± 6 years, from the Whitehall II study. Depressive symptoms were assessed in 2002–2004 using the center-for-epidemiologic-studies-depression-scale (score ≥ 16). RHR was measured at the same study phase via electrocardiogram. Participants were assigned to 1 of 6 risk-factor-groups based on depression status (yes/no) and RHR categories (<60, 60 – 80, >80 bpm). Mean follow-up for mortality was 5.6 years.

Results

In mutually adjusted Cox regression models, depression (hazard ratio = 1.93 p<0.001) and RHR>80 bpm (hazard ratio = 1.67, p<0.001) were independent predictors of mortality. After adjustment for potential confounding and mediating variables, participants with both depression and high RHR had a 3.0-fold higher (p<0.001) risk of death compared to depression-free participants with RHR ranging from 60 to 80 bpm. This risk is particularly marked in participants with prevalent CHD.

Conclusions

This study provides evidence that the coexistence of depressive symptoms and elevated RHR is associated with substantially increased risk of death compared to those without these two factors. This finding raises the possibility that treatments that improve both depression and RHR might improve survival.

Objectives

Cognitive reserve is associated with a lower risk of dementia but the extent to which it shapes cognitive aging trajectories remains unclear. Our objective is to examine the impact of three markers of reserve from different points in the lifecourse on cognitive function and decline in late adulthood.

Methods

Data are from 5234 men and 2220 women, mean age 56 years (standard deviation=6) at baseline, from the Whitehall II cohort study. Memory, reasoning, vocabulary, phonemic and semantic fluency were assessed three times over 10 years. Linear mixed models were used to assess the association between markers of reserve (height, education, and occupation) and cognitive decline, using the 5 cognitive tests and a global cognitive score composed of these tests.

Results

All three reserve measures were associated with baseline cognitive function, with strongest associations with occupation and the weakest with height. All cognitive functions except vocabulary declined over the 10 year follow-up period. On the global cognitive test, there was greater decline in the high occupation group (−0.27; 95% confidence interval (CI): −0.28, −0.26) compared to the intermediate (−0.23; 95% CI: −0.25, −0.22) and low groups (−0.21; 95% CI: −0.24, −0.19); p=0.001. The decline in reserve groups defined by education (p=0.82) and height (p=0.55) was similar.

Interpretation

Cognitive performance over the adult lifecourse was remarkably higher in the high reserve groups. However, rate of cognitive decline did not differ between reserve groups except occupation where there was some evidence of greater decline in the high occupation group.

Objective To quantify the link between lower, subclinically symptomatic, levels of psychological distress and cause-specific mortality in a large scale, population based study.

Design Individual participant meta-analysis of 10 large prospective cohort studies from the Health Survey for England. Baseline psychological distress measured by the 12 item General Health Questionnaire score, and mortality from death certification.

Participants 68 222 people from general population samples of adults aged 35 years and over, free of cardiovascular disease and cancer, and living in private households in England at study baseline.

Main outcome measures Death from all causes (n=8365), cardiovascular disease including cerebrovascular disease (n=3382), all cancers (n=2552), and deaths from external causes (n=386). Mean follow-up was 8.2 years (standard deviation 3.5).

Results We found a dose-response association between psychological distress across the full range of severity and an increased risk of mortality (age and sex adjusted hazard ratio for General Health Questionnaire scores of 1-3 v score 0: 1.20, 95% confidence interval 1.13 to 1.27; scores 4-6: 1.43, 1.31 to 1.56; and scores 7-12: 1.94, 1.66 to 2.26; P<0.001 for trend). This association remained after adjustment for somatic comorbidity plus behavioural and socioeconomic factors. A similar association was found for cardiovascular disease deaths and deaths from external causes. Cancer death was only associated with psychological distress at higher levels.

Conclusions Psychological distress is associated with increased risk of mortality from several major causes in a dose-response pattern. Risk of mortality was raised even at lower levels of distress.

Background

To examine explanations for the higher rates of male mortality in two Scottish cohorts compared with a cohort in south-east England for which similar data were collected.

Methodology/Principal Findings

We compared three cohort studies which recruited participants in the late 1960s and early 1970s. A total of 13,884 men aged 45–64 years at recruitment in the Whitehall occupational cohort (south-east England), 3,956 men in the Collaborative occupational cohort and 6,813 men in the Renfrew & Paisley population-based study (both central Scotland) were included in analyses of all-cause and cause-specific mortality. All-cause mortality was 25% (age-adjusted hazard ratio 1.25, 95% confidence interval (CI)1.21 to 1.30) and 41% (hazard ratio 1.41 (95% CI 1.36 to 1.45) higher in the Collaborative and Renfrew & Paisley cohorts respectively compared to the Whitehall cohort. The higher mortality rates were substantially attenuated by social class (to 8% and 17% higher respectively), and were effectively eliminated upon the further addition of the other baseline risk factors, such as smoking habit, lung function and pre-existing self-reported morbidity. Despite this, coronary heart disease mortality remained 11% and 16% higher, stroke mortality 45% and 37% higher, mortality from accidents and suicide 51% and 70% higher, and alcohol-related mortality 46% and 73% higher in the Collaborative and Renfrew & Paisley cohorts respectively compared with the Whitehall cohort in the fully adjusted model.

Conclusions/Significance

The higher all-cause, respiratory, and lung cancer male mortality in the Scottish cohorts was almost entirely explained by social class differences and higher prevalence of known risk factors, but reasons for the excess mortality from stroke, alcohol-related causes, accidents and suicide remained unknown.

Background

Psychological stress is suggested to accelerate the rate of biological aging. We investigated whether work-related exhaustion, an indicator of prolonged work stress, is associated with accelerated biological aging, as indicated by shorter leukocyte telomeres, that is, the DNA-protein complexes that cap chromosomal ends in cells.

Methods

We used data from a representative sample of the Finnish working-age population, the Health 2000 Study. Our sample consisted of 2911 men and women aged 30–64. Work-related exhaustion was assessed using the Maslach Burnout Inventory - General Survey. We determined relative leukocyte telomere length using a quantitative real-time polymerase chain reaction (PCR) -based method.

Results

After adjustment for age and sex, individuals with severe exhaustion had leukocyte telomeres on average 0.043 relative units shorter (standard error of the mean 0.016) than those with no exhaustion (p = 0.009). The association between exhaustion and relative telomere length remained significant after additional adjustment for marital and socioeconomic status, smoking, body mass index, and morbidities (adjusted difference 0.044 relative units, standard error of the mean 0.017, p = 0.008).

Conclusions

These data suggest that work-related exhaustion is related to the acceleration of the rate of biological aging. This hypothesis awaits confirmation in a prospective study measuring changes in relative telomere length over time.

Background

The clinical utility of identifying pediatric metabolic syndrome (MetS) is controversial. This study sought to determine the status of pediatric MetS as a risk factor for adult subclinical atherosclerosis (carotid intima-media thickness, cIMT) and type 2 diabetes mellitus (T2DM), and compare and contrast this prediction with its individual components.

Methods and Results

Using data from the population-based, prospective, observational Bogalusa Heart and Cardiovascular Risk in Young Finns studies, we examined the utility of four categorical definitions of youth MetS and their components in predicting adult high cIMT, and T2DM among 1781 participants aged 9–18 years at baseline (1984–88) who were then examined 14–27 years later (2001–2007) when aged 24–41 years. Youth with MetS were at 2–3 times the risk of having high cIMT, and T2DM as adults compared with those free of MetS at youth. Risk estimates using high body mass index (BMI) were similar to that of MetS phenotypes in predicting adult outcomes. Comparisons of area under the receiver operating characteristic curve and net reclassification suggested that prediction of adult MetS, high cIMT, and T2DM in adulthood using youth MetS was either equivalent or inferior to classification based on high BMI or overweight and obesity.

Conclusions

Youth with MetS are at increased risk of meaningful adult outcomes, however, the simplicity of screening for high BMI or overweight and obesity in the pediatric setting offers a simpler, equally accurate alternative to identifying youth at risk of developing adult MetS, high cIMT, or T2DM.

Background

Recent studies based on self-reported data suggest that retirement may have beneficial effects on mental health, but studies using objective endpoints remain scarce. This study examines longitudinally the changes in antidepressant medication use across the 9 years spanning the transition to retirement.

Methods

Participants were Finnish public-sector employees: 7138 retired at statutory retirement age (76% women, mean age 61.2 years), 1238 retired early due to mental health issues (78% women, mean age 52.0 years), and 2643 retired due to physical health issues(72% women, mean age 55.4 years). Purchase of antidepressant medication four years prior to and four years after retirement year were based on comprehensive national pharmacy records in 1994-2005.

Results

One year before retirement, the use of antidepressants was 4% among those who would retire at statutory age, 61% among those who would retire due to mental health issues, and 14% among those who would retire due to physical health issues. Retirement-related changes in antidepressant use depended on the reason for retirement. Among old-age retirees, antidepressant medication use decreased during the transition period (age- and calendar-year-adjusted prevalence ratio for antidepressant use 1 year after vs. 1 year before retirement = 0.77 [95% confidence interval = 0.68 – 0.88]). Among those whose main reason for disability pension was mental health issues or physical health issues, there was an increasing trend in antidepressant use prior to retirement and, for mental health retirements, a decrease after retirement.

Conclusions

Trajectories of recorded purchases of antidepressant medication are consistent with the hypothesis that retirement is beneficial for mental health.

The status of stressful life events as a risk factor for asthma is unclear and may be dependent on pre-existing allergic rhinitis. This study examined whether exposure to stressful life events predicted the onset of asthma in adults.

This is a prospective, population-based cohort study of 16,881 men and women, aged 20–54 and free of diagnosed asthma at the beginning of the follow-up (January 1, 2004). Data about stressful life events were gathered with a postal survey. The onset of asthma was ascertained through national registers until December 31, 2005.

During the follow-up period, 192 incident cases of asthma were identified. High total exposure to stressful life events, as indicated by a cumulative severity score, predicted the onset of asthma (HR 1.96; 95% CI 1.22–3.13). This association was robust to adjustment for demographics, smoking, and having a cat/dog at home, and it was observed both among those with and without allergic rhinitis at the baseline. Of the 10 most stressful life events, the illness of a family member, marital problems, divorce or separation, and conflicts with a supervisor were associated with the onset of asthma.

Our study suggests that stressful life events may increase the onset of asthma.

Background

Social determinants of sleep may prove to be as important as health status. In this study we examined the extent to which persistent and changing economic difficulties are associated with sleep problems in two prospective occupational cohorts.

Methods

We used data from Finnish (baseline 2000–2002; follow-up 2007; n = 6328) and British (baseline 1997–1999; follow-up 2003–2004; n = 5002) public sector employees. Economic difficulties, sleep problems, and a variety of covariates were assessed at baseline and follow-up.

Results

Prevalence of frequent sleep problems at follow-up was 27% and 20% among women and men in the Finnish cohort, and 34% and 27% in the British cohort, respectively. Odds for sleep problems were higher among those with persistent economic difficulties (frequent economic difficulties at baseline and follow-up) compared to those with no difficulties. This association remained after multiple adjustments, including parental and current socioeconomic position, in the Finnish (OR 1.72, 95% CI 1.35–2.18) cohort. Increases in economic difficulties were similarly associated with sleep problems in the Finnish and the British cohort.

Conclusion

Evidence from two occupational cohorts suggests strong associations between economic difficulty and poor sleep. Awareness of this association will help health care professionals identify and prevent sleep problems.