Childhood adversity and the risk of gestational diabetes: A population-based cohort study of nulliparous pregnant women

AIMS

Gestational diabetes mellitus (GDM) is one of the most common pregnancy complications, and though it may be linked to childhood adversity, the effect of different types of adversity remains unclear. Childhood adversity is linked to a younger maternal age, which may hide the overall impact of adversity on GDM risk. We therefore aimed to explore the association between different types of childhood adversity and GDM while accounting for the potential impact of maternal age.

METHODS

We used Danish nation-wide register data, including 208,207 women giving birth for the first time from 2004 to 2018. Five adversity groups were used to examine the effect of childhood adversity on GDM risk: (1) low (referent group), (2) early life material deprivation, (3) persistent deprivation, (4) loss or threat of loss within the family and (5) high adversity.

RESULTS

5375 women were diagnosed with GDM in the study population (2.6% absolute risk). Compared to women who experienced low adversity, the other adversity groups had a higher GDM risk (absolute difference [%]) directly; early material deprivation (0.64% [95% CI 0.44; 0.84]), persistent deprivation (0.63% [0.41; 0.86]), loss or threat of loss (0.73% [0.42; 1.05]) and high adversity (0.80% [0.32; 1.27]). The indirect effect of maternal age attenuated the total effect of childhood adversity on GDM by an absolute difference of 0.25%-0.46%.

CONCLUSIONS

Experiencing childhood adversity to any extent is associated with a higher risk of GDM. Interventions aimed at preventing childhood adversity may have a positive effect in reducing GDM burden and the associated health risks.

Variations in sociodemographic and health-related factors are linked to distinct clusters of individuals with depression based on the PHQ-9 instrument: NHANES 2007-2018

BACKGROUND

Depression is a heterogeneous disease. Identification of latent depression subgroups and differential associations across these putative groups and sociodemographic and health-related factors might pave the way toward targeted treatment of individuals.

METHODS

We used model-based clustering to identify relevant subgroups of 2900 individuals with moderate to severe depression (defined as scores ≥10 on the PHQ-9 instrument) from the NHANES cross-sectional survey. We used ANOVA and chi-squared tests to assess associations between cluster membership and sociodemographics, health-related variables, and prescription medication use.

RESULTS

We identified six latent clusters of individuals, three based on depression severity and three differentially loaded by somatic and mental components of the PHQ-9. The Severe mental depression cluster had the most individuals with low education and income (P < 0.05). We observed differences in the prevalence of numerous health conditions, with the Severe mental depression cluster showing the worst overall physical health. We observed marked differences between the clusters regarding prescription medication use: the Severe mental depression cluster had the highest use of cardiovascular and metabolic agents, while the Uniform severe depression cluster showed the highest use of central nervous system and psychotherapeutic agents.

LIMITATIONS

Due to the cross-sectional design we cannot make conclusions about causal relationships. We used self-reported data. We did not have access to a replication cohort.

CONCLUSIONS

We show that socioeconomic factors, somatic diseases, and prescription medication use are differentially associated with distinct and clinically relevant clusters of individuals with moderate to severe depression.

Childhood adversity and risk of type 2 diabetes in early adulthood: results from a population-wide cohort study of 1.2 million individuals

AIMS/HYPOTHESIS

To examine whether childhood adversity is related to development of type 2 diabetes in early adulthood (16 to 38 years) among men and women.

METHODS

We used nationwide register data of 1,277,429 individuals born in Denmark between 1 January 1980 and 31 December 2001, who were still resident in Denmark and without diabetes at age 16 years. Individuals were divided into five childhood adversity groups based on their yearly exposure to childhood adversities (from age 0-15 years) across three dimensions: material deprivation, loss or threat of loss, and family dynamics. We estimated HR and hazard differences (HD) for type 2 diabetes according to the childhood adversity groups using Cox proportional hazards and Aalen additive hazards models.

RESULTS

During follow-up from age 16 to 31 December 2018, 4860 individuals developed type 2 diabetes. Compared with the low adversity group, the risk of type 2 diabetes was higher in all other childhood adversity groups among both men and women. For example, the risk was higher in the high adversity group characterised by high rates of adversity across all three dimensions among men (HR 2.41; 95% CI 2.04, 2.85) and women (1.58; 1.31, 1.91), translating into 36.2 (25.9, 46.5) additional cases of type 2 diabetes per 100,000 person-years among men and 18.6 (8.2, 29.0) among women.

CONCLUSIONS/INTERPRETATION

Individuals who experienced childhood adversity are at higher risk of developing type 2 diabetes in early adulthood. Intervening upon proximal determinants of adversity may help reduce the number of type 2 diabetes cases among young adults.

Psychosocial working conditions and sickness absence among younger employees in Denmark: a register-based cohort study using job exposure matrices

OBJECTIVE

Previous literature has established associations between psychosocial working conditions and sickness absence (SA), but only few studies have examined associations among younger employees. This study aimed to investigate associations between psychosocial working conditions and SA among employees, aged 15-30 years, who entered the labor market in Denmark between 2010 and 2018.

METHOD

We followed 301 185 younger employees in registers for on average 2.6 years. Using job exposure matrices, we assessed job insecurity, quantitative demands, decision authority, job strain, emotional demands, and work-related physical violence. Adjusted rate ratios of SA spells of any length were estimated for women and men separately with Poisson models.

RESULTS

Among women, employment in occupations with high quantitative demands, low decision authority, high job strain, high emotional demands, or high work-related physical violence was associated with higher rates of SA. Being employed in occupations with high versus low emotional demands showed the strongest association with SA, with a rate ratio of 1.44 [95% confidence interval (CI) 1.41-1.47]. Among men, being employed in occupations with low decision authority showed the strongest association with SA (1.34, 95% CI 1.31-1.37), whereas occupations with high quantitative demands, high job strain, and high emotional demands were associated with lower rates of SA.

CONCLUSION

We found that several psychosocial working conditions were associated with SA spells of any length. Associations with SA spells of any length resemble associations with long-term SA, suggesting that results from previous studies on long-term SA may be generalizable to all lengths of SA among younger employees.

Assessing racial bias in type 2 diabetes risk prediction algorithms

Risk prediction models for type 2 diabetes can be useful for the early detection of individuals at high risk. However, models may also bias clinical decision-making processes, for instance by differential risk miscalibration across racial groups. We investigated whether the Prediabetes Risk Test (PRT) issued by the National Diabetes Prevention Program, and two prognostic models, the Framingham Offspring Risk Score, and the ARIC Model, demonstrate racial bias between non-Hispanic Whites and non-Hispanic Blacks. We used National Health and Nutrition Examination Survey (NHANES) data, sampled in six independent two-year batches between 1999 and 2010. A total of 9,987 adults without a prior diagnosis of diabetes and with fasting blood samples available were included. We calculated race- and year-specific average predicted risks of type 2 diabetes according to the risk models. We compared the predicted risks with observed ones extracted from the US Diabetes Surveillance System across racial groups (summary calibration). All investigated models were found to be miscalibrated with regard to race, consistently across the survey years. The Framingham Offspring Risk Score overestimated type 2 diabetes risk for non-Hispanic Whites and underestimated risk for non-Hispanic Blacks. The PRT and the ARIC models overestimated risk for both races, but more so for non-Hispanic Whites. These landmark models overestimated the risk of type 2 diabetes for non-Hispanic Whites more severely than for non-Hispanic Blacks. This may result in a larger proportion of non-Hispanic Whites being prioritized for preventive interventions, but it also increases the risk of overdiagnosis and overtreatment in this group. On the other hand, a larger proportion of non-Hispanic Blacks may be potentially underprioritized and undertreated.

Workplace psychosocial resources and risk of cardiovascular disease among employees: a multi-cohort study of 135 669 participants

OBJECTIVE

In terms of prevention, it is important to determine effects on cardiovascular disease (CVD) when some workplace psychosocial resources are high while others are low. The aim of the study was to assess the prospective relationship between clustering of workplace psychosocial resources and risk of CVD among employees.

METHODS

We pooled data from three cohort studies of 135 669 employees (65% women, age 18-65 years and free of CVD) from Denmark, Finland and Sweden. Baseline horizontal resources (culture of collaboration and support from colleagues) and vertical resources (leadership quality and procedural justice) were measured using standard questionnaire items. Incident CVD, including coronary heart and cerebrovascular disease, was ascertained using linked electronic health records. We used latent class analysis to assess clustering (latent classes) of workplace psychosocial resources. Cox proportional hazard models were used to examine the association between these clusters and risk of CVD, adjusting for demographic and employment-related factors and pre-existing physical and mental disorders.

RESULTS

We identified five clusters of workplace psychosocial resources from low on both vertical and horizontal resources (13%) to generally high resources (28%). High horizontal resources were combined with either intermediate [hazard ratio (HR) 0.84, 95% confidence interval (CI) 0.74-0.95] or high (HR 0.88, 95% CI 0.78-1.00) vertical resources were associated with lower risks of CVD compared to those with generally low resources. The association was most prominent for cerebrovascular disease (eg, general high resources: HR 0.80, 95% CI 0.67-0.96).

CONCLUSIONS

Individuals with high levels of workplace psychosocial resources across horizontal and vertical dimensions have a lower risk of CVD, particularly cerebrovascular disease.

Impact of hypothetical improvements in the psychosocial work environment on sickness absence rates: a simulation study

Background

The association between psychosocial working environments and sickness absence is well-known. However, the potential for reducing sickness absences of different lengths through improvements in psychosocial work factors is not fully understood. We aim to quantify the potential for reducing short-, intermediate- and long-term sickness absence rates, respectively, through hypothetical improvements in several psychosocial work factors.

Methods

This longitudinal study includes 24 990 public hospital employees from the 2014 wave of the Well-being in Hospital Employees study. The 1-year sickness absence rate was divided into short- (1–3 days), intermediate- (4–28 days) and long-term (29 days or more) periods. We simulated hypothetical scenarios with improvements in 17 psychosocial work factors using the parametric g-formula and estimated resulting changes in sickness absence rate ratios (RRs) with 95% confidence intervals (95% CIs).

Results

Setting all 17 psychosocial work factors to their most desirable levels (vs. least desirable levels) was associated with an overall 54% lower rate of sickness absence (95% CI: 48–60%). Reducing bullying (no vs. yes RR: 0.86, 95% CI: 0.83–0.90) and perceived stress (low vs. high RR: 0.90, 95% CI: 0.87–0.92), and increasing skill discretion (high vs. low RR: 0.91, 95% CI: 0.89–0.94) held the largest potential for reducing the total sickness absence rate. Overall, associations were similar for short-, intermediate- and long-term sickness absence.

Conclusions

The psychosocial working environment was strongly associated with sickness absence. Improving the working environment may have a great impact on short-, intermediate- and long-term sickness absence rates.

Organizational Justice and Long-term Metabolic Trajectories: A 25-Year Follow-up of the Whitehall II Cohort

CONTEXT

Organizational justice has been linked to lower risk of several chronic conditions among employees, but less is known about the long-term mechanisms underlying this risk reduction.

OBJECTIVE

To assess whether self-reported organizational justice is associated with individual and composite long-term metabolic trajectories.

DESIGN

Twenty-five-year follow-up of the Whitehall II prospective cohort study.

SETTING

Middle-aged public servants from the United Kingdom.

PARTICIPANTS

Data on 8182 participants were used.

MAIN OUTCOME MEASURES

Levels of 11 anthropometric, glycemic, lipid, and blood pressure biomarkers were measured at 5 timepoints (1991-2013). We used generalized estimating equations and group-based trajectory modeling to investigate the relationship between organizational justice and biomarker trajectories.

RESULTS

High vs low organizational justice were associated with lower waist (-1.7 cm) and hip (-1 cm) circumference, body mass index (-0.6 kg/m2), triglycerides (-1.07 mmol/L), and fasting insulin (-1.08 µIU/mL) trajectories. Two latent metabolic trajectory clusters were identified: a high- and a low-risk cluster. High organizational justice (vs low) were associated with belonging to the low-risk cluster (pooled odds ratio = 1.47). The low-risk cluster demonstrated lower baseline levels of most biomarkers and better glycemic control, whereas the high-risk cluster showed higher baseline levels of most biomarkers, glycemic deterioration, but also greater improvements in lipid levels over time.

CONCLUSIONS

People with high organizational justice had more favorable long-term cardiometabolic biomarker patterns than those with low organizational justice, indicating a potential mechanism contributing to the lower risk of chronic diseases in the first group. Further intervention studies are warranted to determine whether improvement of organizational justice might improve long-term health.

Time trends in mental health indicators during the initial 16 months of the COVID-19 pandemic in Denmark

BACKGROUND

The COVID-19 pandemic and its associated national lockdowns have been linked to deteriorations in mental health worldwide. A number of studies analysed changes in mental health indicators during the pandemic; however, these studies generally had a small number of timepoints, and focused on the initial months of the pandemic. Furthermore, most studies followed-up the same individuals, resulting in significant loss to follow-up and biased estimates of mental health and its change. Here we report on time trends in key mental health indicators amongst Danish adults over the course of the pandemic (March 2020 - July 2021) focusing on subgroups defined by gender, age, and self-reported previously diagnosed chronic and/or mental illness.

METHODS

We used time-series data collected by Epinion (N=8,261) with 43 timepoints between 20 March 2020 and 22 July 2021. Using a repeated cross-sectional study design, independent sets of individuals were asked to respond to the Copenhagen Corona-Related Mental Health questionnaire at each timepoint, and data was weighted to population proportions. The six mental health indicators examined were loneliness, anxiety, social isolation, quality of life, COVID-19-related worries, and the mental health scale. Gender, age, and the presence of previously diagnosed mental and/or chronic illness were used to stratify the population into subgroups for comparisons.

RESULTS

Poorer mental health were observed during the strictest phases of the lockdowns, whereas better outcomes occurred during reopening phases. Women, young individuals (<34 yrs), and those with a mental- and/or chronic illness demonstrated poorer mean time-series than others. Those with a pre-existing mental illness further had a less reactive mental health time-series. The greatest differences between women/men and younger/older age groups were observed during the second lockdown.

CONCLUSIONS

People with mental illness have reported disadvantageous but stable levels of mental health indicators during the pandemic thus far, and they seem to be less affected by the factors that result in fluctuating time-series in other subgroups.

Characteristics of Workplace Psychosocial Resources and Risk of Diabetes: A Prospective Cohort Study

OBJECTIVE

To examine whether characteristics of workplace psychosocial resources are associated with the risk of type 2 diabetes among employees.

RESEARCH DESIGN AND METHODS

Participants were 49,835 employees (77% women, aged 40-65 years, and diabetes free at baseline) from the Finnish Public Sector cohort study. Characteristics of horizontal (culture of collaboration and support from colleagues) and vertical (leadership quality and organizational procedural justice) psychosocial resources were self-reported. Incident type 2 diabetes (n = 2,148) was ascertained through linkage to electronic health records from national registers. We used latent class modeling to assess the clustering of resource characteristics. Cox proportional hazards models were used to examine the relationship between the identified clusters and risk of type 2 diabetes during 10.9 years of follow-up, adjusting for age, sex, marital status, educational level, type of employment contract, comorbidity, and diagnosed mental disorders.

RESULTS

We identified four patterns of workplace psychosocial resources: unfavorable, favorable vertical, favorable horizontal, and favorable vertical and horizontal. Compared with unfavorable, favorable vertical (hazard ratio 0.87 [95% CI 0.78; 0.97]), favorable horizontal (0.77 [0.67; 0.88]), and favorable vertical and horizontal (0.77 [0.68; 0.86]) resources were associated with a lower risk of type 2 diabetes, with the strongest associations seen in employees at age ≥55 years (Pinteraction = 0.03). These associations were robust to multivariable adjustments and were not explained by reverse causation.

CONCLUSIONS

A favorable culture of collaboration, support from colleagues, leadership quality, and organizational procedural justice are associated with a lower risk of employees developing type 2 diabetes than in those without such favorable workplace psychosocial resources.

Mental health indicators in pregnant women compared with women in the general population during the coronavirus disease 2019 pandemic in Denmark

Introduction

The coronavirus disease 2019 (COVID‐19) pandemic and the associated regulations issued to minimize risk of disease transmission seem to have had an impact on general mental health in most populations, but it may have affected pregnant women even more because of pregnancy‐related uncertainties, limited access to healthcare resources, and lack of social support. We aimed to compare the mental health response among pregnant women with that in similarly aged women from the general population during the first wave of the COVID‐19 pandemic.

Material and methods

From April 14 to July 3, 2020, 647 pregnant women in their second trimester were enrolled in this study. For comparison, 858 women from the general Danish population (20–46 years) were sampled from an ongoing observational study. Participants responded to a questionnaire including six mental health indicators (concern level, perceived social isolation, quality of life, anxiety, mental health, and loneliness). Loneliness was measured using the UCLA Three‐item Loneliness Scale and anxiety by the Common Mental Health Disorder Questionnaire 4‐item Anxiety Subscale.

Results

The pregnant women had better scores during the entire study period for all mental health indicators, and except for concerns, social isolation, and mental health, the differences were also statistically significant. Pregnant women were more concerned about becoming seriously ill (40.2% vs. 29.5%, p < 0.001), whereas the general population was more concerned about economic consequences and prospects. Many pregnant women reported negative feelings associated with being pregnant during the COVID‐19 pandemic and concerns regarding social isolation and regulation‐imposed partner absence during hospital appointments and childbirth. All mental health indicators improved as Denmark began to reopen after the first wave of the pandemic.

Conclusions

Pregnant women exhibited lower rates of poor mental health compared with the general population. However, they were more concerned about becoming seriously ill, expressed negative feelings about being pregnant during the pandemic, and were worried about the absence of their partner due to imposed regulations. These finding may be taken into account by policy‐makers during pandemics to balance specific preventive measures over the potential mental health deterioration of pregnant women.

Loneliness, worries, anxiety, and precautionary behaviours in response to the COVID-19 pandemic: A longitudinal analysis of 200,000 Western and Northern Europeans

BACKGROUND

In response to the COVID-19 pandemic, governments around the world instituted various public-health measures. Our project aimed to highlight the most significant similarities and differences in key mental-health indicators between four Western and Northern European countries, and identify the population subgroups with the poorest mental-health outcomes during the first months of the pandemic.

METHODS

We analysed time-series survey data of 205,084 individuals from seven studies from Denmark, France, the Netherlands, and the UK to assess the impact of the pandemic and associated lockdowns. All analyses focused on the initial lockdown phase (March-July 2020). The main outcomes were loneliness, anxiety, and COVID-19-related worries and precautionary behaviours.

FINDINGS

COVID-19-related worries were consistently high in each country but decreased during the gradual reopening phases. While only 7% of the respondents reported high levels of loneliness in the Netherlands, percentages were higher in the rest of the three countries (13-18%). In all four countries, younger individuals and individuals with a history of mental illness expressed the highest levels of loneliness.

INTERPRETATION

The pandemic and associated country lockdowns had a major impact on the mental health of populations, and certain subgroups should be closely followed to prevent negative long-term consequences. Younger individuals and individuals with a history of mental illness would benefit from tailored public-health interventions to prevent or counteract the negative effects of the pandemic. Individuals across Western and Northern Europe have thus far responded in psychologically similar ways despite differences in government approaches to the pandemic.

FUNDING

See the Funding section.

Trajectories of Childhood Adversity and Type 1 Diabetes: A Nationwide Study of One Million Children

OBJECTIVE

Experiencing adversities in childhood may increase the risk of type 1 diabetes through hyperactivation of the stress response system, but the empirical evidence is conflicting. We aim to describe the age-specific incidence of type 1 diabetes for males and females separately in five predefined groups covering the most common trajectories of adversity among Danish children.

RESEARCH DESIGN AND METHODS

We included all 1,081,993 children without parental type 1 diabetes born in Denmark from 1980 to 1998. We used register data to estimate age-specific incidence rates of type 1 diabetes in five trajectory groups of adversity characterized by 1) low adversity, 2) early life material deprivation, 3) persistent material deprivation, 4) loss or threat of loss in the family, and 5) cumulative high adversity. All analyses were stratified by sex.

RESULTS

In total, 5,619 people developed type 1 diabetes before 2016. We found only minor differences when comparing the incidence rates of type 1 diabetes between the trajectory groups. The only clear exceptions were in the high versus low adversity group, in which males had a higher incidence of type 1 diabetes in childhood (<11 years [incidence rate ratio (IRR) 1.78 (95% CI 1.31-2.42)]) and females had a higher incidence in early adulthood (≥16 years [IRR 2.19 (95% CI 1.57-3.07)]).

CONCLUSIONS

Childhood adversities were generally not associated with age-specific incidence of type 1 diabetes except among those exposed to a very high and increasing annual rate of childhood adversities. Differences between highly exposed males and females seem to depend on age at onset of type 1 diabetes.

Onset of Workplace Bullying and Risk of Weight Gain: A Multicohort Longitudinal Study

OBJECTIVE

This study aimed to examine the onset of workplace bullying as a risk factor for BMI increase.

METHODS

Repeated biennial survey data from three Nordic cohort studies were used, totaling 46,148 participants (67,337 participant observations) aged between 18 and 65 who did not have obesity and who were not bullied at the baseline. Multinomial logistic regression was applied for the analysis under the framework of generalized estimating equations.

RESULTS

Five percent reported onset of workplace bullying within 2 years from the baseline. In confounder-adjusted models, onset of workplace bullying was associated with a higher risk of weight gain of ≥ 1 BMI unit (odds ratio = 1.09; 95% CI: 1.01-1.19) and of ≥ 2.5 BMI units (odds ratio = 1.24; 95% CI: 1.06-1.45). A dose-response pattern was observed, and those exposed to workplace bullying more frequently showed a higher risk (P_trend  = 0.04). The association was robust to adjustments, restrictions, stratifications, and use of relative/absolute scales for BMI change.

CONCLUSIONS

Participants with exposure to the onset of workplace bullying were more likely to gain weight, a possible pathway linking workplace bullying to increased long-term risk of type 2 diabetes.

Accumulation of childhood adversities and type 1 diabetes risk: a register-based cohort study of all children born in Denmark between 1980 and 2015

BACKGROUND

Previous studies have indicated an association between childhood adversities and type 1 diabetes but have been underpowered and limited by selection. We aim to quantify the effect of accumulation of childhood adversities on type 1 diabetes risk, and to assess whether the effect differs between males and females in a large and unselected population sample.

METHODS

We used register-based data covering all children born in Denmark between 1980 and 2015, totalling >2 million children. We specified a multi-state model to quantify the effect of accumulation of childhood adversities on type 1 diabetes risk. The effects of specific childhood adversities on type 1 diabetes were estimated using proportional hazards models.

RESULTS

Accumulation of childhood adversities had a quantitatively small effect on type 1 diabetes risk among females [adjusted hazard ratio (HR) per adversity increase: 1.07; 95% confidence interval (CI): 1.02-1.11], but not among males (adjusted HR per adversity increase: 0.99; 95% CI: 0.97-1.03). Females exposed to extreme numbers (7+) of adversities had two times higher risk of type 1 diabetes compared with unexposed females (adjusted HR: 2.06; 95% CI: 1.10-3.86).

CONCLUSIONS

In an unselected total population sample, we generally find no or negligible effects of childhood adversities on type 1 diabetes risk, which may be reassuring to persons with type 1 diabetes who are concerned that personal trauma contributed to their disease. There is a very small group of females exposed to a high degree of adversity who may have a higher risk of type 1 diabetes and this group needs further attention.

Education and incident type 2 diabetes: quantifying the impact of differential exposure and susceptibility to being overweight or obese

AIMS/HYPOTHESIS

Educational inequality in type 2 diabetes incidence is evident in many high-income countries. Previous studies have shown that differential exposure to being overweight/obese across educational groups may partly explain this inequality. Whether differential susceptibility to being overweight/obese across educational groups contributes to this inequality has been investigated less frequently, even though it is a plausible mechanism. The two mechanisms may even be highly intertwined. In this longitudinal cohort study, we investigated the simultaneous contribution of differential exposure and differential susceptibility to being overweight/obese to educational inequality in type 2 diabetes incidence.

METHODS

The study population comprised 53,159 Danish men and women aged 50-64 years at baseline who were followed for a mean of 14.7 years. We estimated rate differences of type 2 diabetes by education level per 100,000 person-years. Using counterfactual mediation analysis, these rate differences were decomposed into proportions attributable to differential exposure, differential susceptibility and all other pathways, respectively. We compared this approach with conventional approaches to mediation and interaction analysis.

RESULTS

Compared with a high level of education, a low education level was associated with 454 (95% CI 398, 510) additional cases of type 2 diabetes, and a medium education level with 316 (CI 268, 363) additional cases. Differential exposure to being overweight/obese accounted for 37% (CI 31%, 45%) of the additional cases among those with a low education level and 29% (CI 24%, 36%) of the additional cases among those with a medium education level. Differential susceptibility accounted for 9% (CI 4%, 14%) and 6% (CI 3%, 10%) of the additional cases among those with a low and medium education level, respectively. Compared with the counterfactual approach, the conventional approaches suggested stronger effects of both mechanisms.

CONCLUSIONS/INTERPRETATION

Differential exposure and susceptibility to being overweight/obese are both important mechanisms in the association between education and type 2 diabetes incidence.

Trajectories of childhood adversity and mortality in early adulthood: a population-based cohort study

BACKGROUND

Childhood is a sensitive period with rapid brain development and physiological growth, and adverse events in childhood might interfere with these processes and have long-lasting effects on health. In this study, we aimed to describe trajectories of adverse childhood experiences and relate these to overall and cause-specific mortality in early adult life.

METHODS

For this population-based cohort study, we used unselected annually updated data from Danish nationwide registers covering more than 1 million children born between 1980 and 1998. We distinguished between three different dimensions of childhood adversities: poverty and material deprivation, loss or threat of loss within the family, and aspects of family dynamics such as maternal separation. We used a group-based multi-trajectory clustering model to define the different trajectories of children aged between 0 and 16 years. We assessed the associations between these trajectories and mortality rates between 16 and 34 years of age using a Cox proportional hazards model and an Aalen hazards difference model.

FINDINGS

Between Jan 1, 1980 and Dec 31, 2015, 2 223 927 children were included in the Danish Life Course cohort. We excluded 1 064 864 children born after 1998, 50 274 children who emigrated before their 16th birthday, and 11 161 children who died before their 16th birthday, resulting in a final sample of 1 097 628 children. We identified five distinct trajectories of childhood adversities. Compared with children with a low adversity trajectory, those who had early-life material deprivation (hazard ratio 1·38, 95% CI 1·27-1·51), persistent deprivation (1·77, 1·62-1·93), or loss or threat of loss (1·80, 1·61-2·00) had a moderately higher risk of premature mortality. A small proportion of children (36 081 [3%]) had multiple adversities within all dimensions and throughout the entire childhood. This group had a 4·54 times higher all-cause mortality risk (95% CI 4·07-5·06) than that of children with a low adversity trajectory, corresponding to 10·30 (95% CI 9·03-11·60) additional deaths per 10 000 person-years. Accidents, suicides, and cancer were the most common causes of death in this high adversity population.

INTERPRETATION

Almost half of Danish children in our study experienced some degree of adversity, and this was associated with a moderately higher risk of mortality in adulthood. Among these, a small group of children had multiple adversities across social, health, and family-related dimensions. This group had a markedly higher mortality risk in early adulthood than that of other children, which requires public health attention.

FUNDING

None.

Changes in effort-reward imbalance at work and risk of onset of sleep disturbances in a population-based cohort of workers in Denmark

Objective/background

Associations between exposure to effort-reward imbalance at work (eg, high time pressure/low appreciation) and risk of sleep disturbances have been reported, but the direction of the effect is unclear. The present study investigated changes in effort-reward imbalance and risk of concomitant and subsequent onset of sleep disturbances.

Methods

Participants with sleep disturbances at baseline were excluded. We included participants from a population-based cohort in Denmark (n = 8,464, 53.6% women, mean age = 46.6 years), with three repeated measurements (2012 (T₀); 2014 (T₁); 2016 (T₂)). Changes in effort-reward imbalance (T₀-T₁) were categorized into 'increase', 'decrease' and 'no change'. Self-reported sleep disturbances (difficulties initiating or maintaining sleep, non-restorative sleep, daytime tiredness) were dichotomized (presence versus absence). We regressed concomitant (T₁) and subsequent (T₂) sleep disturbances on changes in effort-reward imbalance (T₀-T₁) and calculated odds ratios (OR) and 95% confidence intervals, adjusted for sex, age, education and cohabitation.

Results

At follow-up, 8.4% (T₁) and 12.5% (T₂) reported onset of sleep disturbances. Increased effort-reward imbalance was associated with concomitant sleep disturbances (T₁) (OR = 3.16, 2.56-3.81), whereas decreased effort-reward imbalance was not (OR = 1.22, 0.91-1.63). There was no association between increased effort-reward imbalance and subsequent sleep disturbances (T₂) (OR = 1.00, 0.74-1.37). Results were similar for men and women.

Conclusions

Increased effort-reward imbalance was associated with a three-fold higher risk of concomitant onset of sleep disturbances at two-year follow-up, but not subsequent onset of sleep disturbances at four-year follow-up, indicating that changes in effort-reward imbalance have immediate rather than delayed effects on sleep impairment. It is possible that the results from the two-year follow-up were to some extent affected by reverse causality.

Job insecurity and risk of coronary heart disease: Mediation analyses of health behaviors, sleep problems, physiological and psychological factors

Job insecurity has been linked to increased risk of coronary heart disease (CHD), but underlying mechanisms remain uncertain. Our aim was to assess the extent to which this association is mediated through life style, physiological, or psychological factors. A total of 3917 men and women free from CHD provided data on job insecurity in the Whitehall II cohort study in 1997-1999. The association between job insecurity and CHD was decomposed into a direct and indirect effect mediated through unhealthy behaviors (smoking, high alcohol consumption, physical inactivity), sleep disturbances, 'allostatic load', or psychological distress. The counterfactual analyses on psychological distress indicated a marginally significant association between job insecurity and incident CHD (hazard ratio (HR) 1.32; 95 % confidence interval (CI) 1.00-1.75). This association was decomposed into a direct (HR 1.22, 95 %CI 0.92-1.63) and indirect association (1.08, 95 %CI 1.01-1.15), suggesting that about 30 % of the total relationship was mediated by psychological distress. No mediation was indicated via health behaviors, sleep disturbances, or allostatic load, although job insecurity was related to disturbed sleep and C-reactive protein, which, in turn were associated with CHD. In conclusion, our results suggest that psychological distress may play a role in the relation between job insecurity and CHD.

Workplace bullying and workplace violence as risk factors for cardiovascular disease: a multi-cohort study

AIMS

To assess the associations between bullying and violence at work and cardiovascular disease (CVD).

METHODS AND RESULTS

Participants were 79 201 working men and women, aged 18-65 years and free of CVD and were sourced from three cohort studies from Sweden and Denmark. Exposure to workplace bullying and violence was measured at baseline using self-reports. Participants were linked to nationwide health and death registers to ascertain incident CVD, including coronary heart disease and cerebrovascular disease. Study-specific results were estimated by marginal structural Cox regression and were combined using fixed-effect meta-analysis. Nine percent reported being bullied at work and 13% recorded exposure to workplace violence during the past year. We recorded 3229 incident CVD cases with a mean follow-up of 12.4 years (765 in the first 4 years). After adjustment for age, sex, country of birth, marital status, and educational level, being bullied at work vs. not was associated with a hazard ratio (HR) of 1.59 [95% confidence interval (CI) 1.28-1.98] for CVD. Experiencing workplace violence vs. not was associated with a HR of 1.25 (95% CI 1.12-1.40) for CVD. The population attributable risk was 5.0% for workplace bullying and 3.1% for workplace violence. The excess risk remained similar in analyses with different follow-up lengths, cardiovascular risk stratifications, and after additional adjustments. Dose-response relations were observed for both workplace bullying and violence (Ptrend < 0.001). There was only negligible heterogeneity in study-specific estimates.

CONCLUSION

Bullying and violence are common at workplaces and those exposed to these stressors are at higher risk of CVD.

Education and T2DM: the role of differential exposure and susceptibility to overweight and obesity

Background

There is a clear educational gradient in type 2 diabetes and differential exposure and susceptibility to overweight and obesity across educational groups may explain part of this gradient. Previous studies have mainly addressed differential exposure to overweight/obesity, even though the pathways are highly intertwined. We take advantage of novel methodological developments to assess the simultaneous contribution of both pathways. We further compare these analyses to more traditional approaches.

Methods

A prospective cohort of 53,159 Danish men and women, aged 50-64 years at enrollment in 1993-1997, were followed for a mean of 14.7 years. We used national register data to ascertain education and incident type 2 diabetes. Overweight/obesity was determined by BMI. Using a marginal structural approach and a three-way effect decomposition, we estimated rate differences of type 2 diabetes by education and decomposed these into direct, indirect and mediated interactive proportions. We compared this approach to traditional and separate approaches to mediation and interaction analysis.

Results

Compared with high education, medium education was associated with 316 (95% CI: 268-363) extra cases of type 2 diabetes per 100,000 person-years, and low education with 454 (95% CI: 398-510) extra cases. Differential exposure to overweight/obesity accounted for 29% (95% CI: 24-36) and 37% (95% CI: 31-45) of the cases in the medium and low educational levels, respectively, while differential susceptibility accounted for 6% (95% CI: 3-10) and 9% (95%CI 4-14). Traditional approaches suggested stronger effects of both pathways.

Conclusions

Differential exposure and susceptibility to overweight/obesity are both important pathways in the education-type 2 diabetes association, and the results emphasize the importance of addressing them simultaneously.

Key messages

Lower educated groups are more exposed and susceptible to the adverse effects of overweight/obesity with regard to type 2 diabetes, suggesting a large preventive potential. Future studies could benefit from estimating both differential exposure and differential susceptibility to better understand social inequality in type 2 diabetes and other health outcomes.

Sleep Duration and Sleep Disturbances as Predictors of Healthy and Chronic Disease-Free Life Expectancy Between Ages 50 and 75: A Pooled Analysis of Three Cohorts

Background

The aim of this study was to examine the associations of sleep duration and sleep disturbances with healthy and chronic disease-free life expectancy (LE) between ages 50 and 75.

Methods

Data were drawn from repeated waves of three occupational cohort studies in England, Finland, and Sweden (n = 55,494) and the follow-up ranged from 6 to 18 years. Self-reported sleep duration was categorized into <7, 7-8.5, and ≥9 hours and sleep disturbances into no, moderate, and severe. Health expectancy was estimated with two health indicators: healthy LE based on years in good self-rated health and chronic disease-free LE based on years without chronic diseases. Multistate life table models were used to estimate healthy and chronic disease-free LE from age 50 to 75 years for each category of sleep measures in each cohort. Fixed-effects meta-analysis was used to pool the cohort-specific results into summary estimates.

Results

Persons who slept 7-8.5 hours could expect to live 19.1 (95% CI 19.0-19.3) years in good health and 13.5 (95% CI 13.2-13.7) years without chronic diseases between ages 50 and 75. Healthy and disease-free years were 1-3 years shorter for those who slept less than 7 hours or slept 9 hours or more. Persons who did not have sleep disturbances could expect to live 20.4 (95% CI 20.3-20.6) years in good health and 14.3 (95% CI 14.1-14.5) years without chronic diseases between ages 50 and 75. Healthy and disease-free years were 6-3 years shorter for those who reported severe sleep disturbances.

Conclusions

Sleeping 7-8.5 hours and having no sleep disturbances between ages 50 to 75 are associated with longer healthy and chronic disease-free LE.

Economic hardship over twenty-two consecutive years of adult life and markers of early ageing

Background

The authors examined the associations between annual measures of economic hardship (EH) across 22 years of adulthood and objective measures of early ageing in a Danish late-middle aged population.

Methods

A linkage of longitudinal register data from Statistics Denmark covering the period 1987-2008 and cross-sectional survey data from the Copenhagen Ageing and Midlife Biobank collected in 2009-11 (N = 5,575). EH was defined as &lt; 60% of the National median equivalized household disposable income and two exposures were calculated: 1) a categorical measure of total number if years in EH, and 2) trajectories of the probability of EH being low, declining, rising or high. Early ageing outcomes included four measures of physical capability, three inflammatory markers and one cognitive test. Associations were analyzed using linear regression models adjusted for sex, age, cohort, education, baseline income and long-term parental unemployment/financial problems.

Results

Four or more years in EH (reference=null years in EH) was related to poorer physical capability (chair rise: -1.49 counts/30 seconds [95% confidence interval (CI) -2.36, -0.61], hand grip strength: -1.22 kg [95% CI -2.38, -0.07], jump height: -1.67 cm [95% CI -2.44, -0.91] and balance: 18% [95% CI 9, 28]), poorer cognitive function (Intelligenz-Struktur-Test: -1.50 points [95% CI -2.89, -0.12]) and higher inflammatory levels (C-reactive protein: 22% [95% CI 4, 44], and Interleukin-6: 23% [95% CI 10, 39]). Comparing the four EH trajectories, people with a high vs. low probability of EH over time had poorer physical capability (chair rise: -1.70 counts/30 seconds [95% CI -3.38, -0.01], grip: -4.33 kg [95% CI -6.50, -2.16], jump: -1.68 cm [95% CI -3.12, -0.25], and balance: 31% [95% CI 12, 52]). No associations were observed with Tumor necrosis factor α.

Conclusions

This study suggests that sustained EH across adulthood may lead to early ageing.

Key messages

Sustained economic hardship in adulthood may lead to early ageing. Being in economic hardship for a few years is not associated with early ageing.

Antidepressant treatment among social workers, human service professionals, and non-human service professionals: A multi-cohort study in Finland, Sweden and Denmark

BACKGROUND

Social workers have an elevated risk for mental disorders, but little is known about their antidepressant treatment.

AIMS

To examine any and long-term antidepressant treatment among social workers in Finland, Sweden and Denmark.

METHODS

We linked records from drug prescription registers to three prospective cohorts: the Finnish Public Sector study, years 2006-2011, and nation-wide cohorts in Sweden and Denmark, years 2006-2014, including a total of 1.5 million employees in (1) social work, (2) other social and health care professions, (3) education and (4) office work. We used Cox proportional hazards models to estimate hazard ratios for any and long-term (>6 months) antidepressant treatment among social workers compared to the three reference occupational groups and carried out meta-analyses.

RESULTS

During follow-up, 25% of social workers had any prescriptions for antidepressants (19-24% reference occupations) and 20% for long-term treatment (14-19% reference occupations). The pooled effects for any and long-term treatment showed that probabilities were 10% higher in social workers compared to other health and social care professionals and 30% higher compared to education and non-human service professionals. Probabilities for any treatment in the three countries were relatively similar, but for long-term treatment social workers in Finland had a greater risk compared with other human service professions.

LIMITATIONS

There were differences between the cohorts in the availability of data. Specific diagnoses for the antidepressant treatment were not known neither adherence to treatment.

CONCLUSION

Social workers have a higher risk for any and long-term antidepressant treatment than other human and non-human service professionals.

Does inflammation provide a link between psychosocial work characteristics and diabetes? Analysis of the role of interleukin-6 and C-reactive protein in the Whitehall II cohort study

OBJECTIVE

Inflammation may underlie the association between psychological stress and cardiometabolic diseases, but this proposition has not been tested longitudinally. We investigated whether the circulating inflammatory markers interleukin-6 (IL-6) and C-reactive protein (CRP) mediate the relationship between psychosocial work characteristics and diabetes.

METHODS

We used three phases of data at 5 years intervals from the Whitehall II cohort study, originally recruiting 10,308 civil service employees aged 35-55 years. The data included repeat self-reports of job demands, control and social support, IL-6 from plasma samples, CRP from serum samples, and diabetes, ascertained through oral glucose tolerance test, medications, and self-reports of doctor-diagnosed diabetes.

RESULTS

Structural equation models with age, sex and occupational position considering men and women combined, showed that low social support at work, but not high job demands or low job control, was prospectively associated with diabetes (standardized ß  =  0.05, 95% confidence interval (CI) 0.01-0.09) and higher levels of IL-6 (ß  =  0.03, CI 0.00-0.06). The inflammatory markers and diabetes were bidirectionally associated over time. A mediation model including workplace social support, IL-6 and diabetes further showed that 10% of the association between social support and diabetes over the three repeat examinations (total effect ß  =  0.08, CI 0.01-0.15) was attributable to a weak indirect effect through IL-6 (ß  =  0.01, CI 0.00-0.02). A similar indirect effect was observed for CRP in men only, while job control was prospectively associated with IL-6 among women.

CONCLUSIONS

This study indicates an association between poor workplace support and diabetes that is partially ascribed to an inflammatory response.

Measuring social integration and tie strength with smartphone and survey data

Recordings of smartphone use for contacts are increasingly being used as alternative or supplementary measurement methods for social interactions and social relations in the health sciences. Less work has been done to understand how these measures compare with widely used survey-based information. Using data from the Copenhagen Network Study, we investigated whether derived survey and smartphone measures on two widely studied concepts; Social integration and Tie strength were associated. The study population included 737 college students (mean age 21.6 years, Standard deviation: 2.6), who were followed with surveys and continuous recordings of smartphone usage over a one-month period. We derived self-reported and smartphone measures of social integration (social role diversity, social network size), and tie strength (contact frequency, duration and tie reciprocity). Logistic regression models were used to assess the associations between smartphone derived and self-reported measures adjusting for gender, age and co-habitation. Larger call and text message networks were associated with having a high self-reported social role diversity, and a high self-reported social contact frequency was likewise associated with having both frequent call and text message interactions, longer call duration and a higher level of reciprocity in call and text message communication. Self-reported aspects of social relations and smartphone measures of social interactions have considerable overlap supporting a measurement of similar underlying concepts.

Longitudinal associations between organizational change, work-unit social capital, and employee exit from the work unit among public healthcare workers: a mediation analysis

Objectives Organizational changes are associated with higher rates of subsequent employee exit from the workplace, but the mediating role of social capital is unknown. We examined the associations between organizational changes and subsequent employee exit from the work unit and mediation through social capital. Methods Throughout 2013, 14 059 healthcare employees worked in the Capital Region of Denmark. Data on work-unit changes (yes/no) from July‒December 2013 were collected via a survey distributed to all managers (merger, split-up, relocation, change of management, employee layoff, budget cuts). Eight employee-reported items assessing social capital were aggregated into work-unit measures (quartiles: low-high). Data on employee exit from the work unit in 2014 were obtained from company registries. Results We found a somewhat higher rate of employee exit from the work unit after changes versus no changes [hazard ratio (HR) 1.10, 95% confidence interval (CI) 1.01-1.19] and an inverse dose‒response relationship between social capital and employee-exit rates (low versus high: HR 1.65, 95% CI 1.46-1.86). We also showed a higher risk of low social capital in work units exposed to changes [low versus high: odds ratio (OR) 2.04, 95% CI 1.86-2.23]. Accounting for potential mediation through social capital seemed slightly to reduce the association between changes and employee-exit rates (HR 1.07, 95% CI 0.98-1.16 versus HR 1.10). Conclusions Work-unit organizational changes prospectively predict lower work-unit social capital, and lower social capital is associated with higher employee-exit rates. Detection of weak indications of mediation through social capital, if any, were limited by inconsistent associations between changes and employee exit from the work unit.

Parental break-ups and stress: roles of age & family structure in 44 509 pre-adolescent children

Background

Parental break-up is wide spread, and the effects of parental break-up on children's well-being are known. The evidence regarding child age at break-up and subsequent family arrangements is inconclusive. Aim: to estimate the effects of parental break-up on stress in pre-adolescent children with a specific focus on age at break-up and post-breakup family arrangements.

Methods

We used data from the Danish National Birth Cohort. Participants included 44 509 children followed from birth to age 11. Stress was self-reported by children at age 11, when the children also reported on parental break-up and post break-up family arrangements.

Results

Twenty-one percent of the children had experienced a parental break-up at age 11, and those who had experienced parental break-up showed a higher risk of stress (OR:1.72, 95%CI:1.55;1.91) regardless of the child's age at break-up. Children living in a new family with stepparents (OR = 1.63, 95%CI:1.38;1.92), or shared between the parents (OR = 1.48, 95%CI:1.26;1.75) reported higher stress than children of intact families. Single parent families reported markedly higher stress levels than children in intact families (OR = 2.18, 95%CI:1.90;2.50) and all other family types. Children who were satisfied with their living arrangements post-break-up reported the same stress level as children living in intact families (OR = 1.01, 95%CI:0.86;1.18).

Conclusion

Children who experience parental break-up have higher stress levels, also many years after the break-up, and those living in a single parent household post break-up seem to be most vulnerable. Living arrangements post-breakup should be further investigated as a potential protective factor.

Job strain and loss of healthy life years between ages 50 and 75 by sex and occupational position: analyses of 64 934 individuals from four prospective cohort studies

Objectives

Poor psychosocial working conditions increase the likelihood of various types of morbidity and may substantially limit quality of life and possibilities to remain in paid work. To date, however, no studies to our knowledge have quantified the extent to which poor psychosocial working conditions reduce healthy or chronic disease-free life expectancy, which was the focus of this study.

Methods

Data were derived from four cohorts with repeat data: the Finnish Public Sector Study (Finland), GAZEL (France), the Swedish Longitudinal Occupational Survey of Health (Sweden) and Whitehall II (UK). Healthy (in good self-rated health) life expectancy (HLE) and chronic disease-free (free from cardiovascular disease, cancer, respiratory disease and diabetes) life expectancy (CDFLE) was calculated from age 50 to 75 based on 64 394 individuals with data on job strain (high demands in combination with low control) at baseline and health at baseline and follow-up.

Results

Multistate life table models showed that job strain was consistently related to shorter HLE (overall 1.7 years difference). The difference in HLE was more pronounced among men (2.0 years compared with 1.5 years for women) and participants in lower occupational positions (2.5 years among low-grade men compared with 1.7 years among high-grade men). Similar differences in HLE, although smaller, were observed among those in intermediate or high occupational positions. Job strain was additionally associated with shorter CDFLE, although this association was weaker and somewhat inconsistent.

Conclusions

These findings suggest that individuals with job strain have a shorter health expectancy compared with those without job strain.

Loneliness and objectively measured physical capability in middle-aged adults

Background

Loneliness is associated with poor functional ability in older people. Little is known about this association in the middle-aged. The aim is to investigate if perceived loneliness is associated with lower physical capability among middle-aged men and women and if the associations of loneliness with physical capability interact with socioeconomic position and cohabitation status.

Methods

5224 participants from Copenhagen Aging and Midlife Biobank (CAMB) aged 49-62 years (mean age 54) were included. Handgrip strength (measured by a dynamometer) and maximal number of chair rises in 30 s was recorded. Multivariate linear regression analyses were adjusted for age, occupational social class, cohabitation status, morbidity and personality traits.

Results

No association was found between loneliness and physical capability. For example estimates for handgrip strength in 'often' lonely men and women compared with the 'not lonely' were 1.2 kg (95% CI - 0.5;2.9)/1.0 kg (-0.7;2.6). Low occupational social class was associated with poorer physical capability, and living alone was associated with poorer handgrip strength in men [-2.4 kg (95% CI - 3.2;-1.5)] and poorer chair rise test in women [-0.8 rises (95% CI - 1.6;-0.1)]. There was no support for interactions.

Conclusion

In contrast to earlier studies among older people, no association between loneliness and physical capability was found in this cohort of middle-aged men and women. Loneliness may not yet have resulted in detectable differences in physical capability in this age group. Further research is needed to clarify if, and at what point in the life course loneliness begins to affect physical capability.

Workplace bullying and violence as risk factors for type 2 diabetes: a multicohort study and meta-analysis

AIMS/HYPOTHESIS

The aim of this multicohort study was to examine whether employees exposed to social stressors at work, such as workplace bullying and violence, have an increased risk of type 2 diabetes.

METHODS

The study included 45,905 men and women (40-65 years of age and free of diabetes at baseline) from four studies in Sweden, Denmark and Finland. Workplace bullying and violence were self-reported at baseline. Incident diabetes was ascertained through national health and medication records and death registers. Marginal structural Cox models adjusted for age, sex, country of birth, marital status and educational level were used for the analyses.

RESULTS

Nine per cent of the population reported being bullied at work and 12% were exposed to workplace violence or threats of violence. Bullied participants had a 1.46 (95% CI 1.23, 1.74) times higher risk of developing diabetes compared with non-bullied participants. Exposure to violence or threats of violence was also associated with a higher risk of diabetes (HR 1.26 [95% CI 1.02, 1.56]). The risk estimates attenuated slightly when taking BMI into account, especially for bullying. The results were similar for men and women, and were consistent across cohorts.

CONCLUSIONS/INTERPRETATION

We found a higher risk of incident type 2 diabetes among employees exposed to bullying or violence in the workplace. Further research is needed to determine whether policies to reduce bullying and violence at work may reduce the incidence of type 2 diabetes in working populations. Research on the mechanisms is also highly warranted.

Change in Job Strain as a Predictor of Change in Insomnia Symptoms: Analyzing Observational Data as a Non-randomized Pseudo-Trial

Study objectives:

To examine whether change in job strain leads to change in insomnia symptoms.

Methods:

Among 24873 adults (82% women, mean age 44 years) who participated in a minimum of three consecutive study waves (2000–2012), job strain was assessed at the first and second wave and insomnia symptoms at all three waves. We analyzed observational data as a “pseudo-trial” including participants with no job strain in the first wave and no insomnia symptoms in the first and second wave (n = 7354) to examine whether the onset of job strain between the first and second waves predicted the onset of insomnia symptoms in the third wave. We used a corresponding approach, including those with job strain in the first wave and insomnia symptoms in the first and second wave (n = 2332), to examine whether the disappearance of job strain between the first two waves predicted remission of insomnia symptoms in the third wave.

Results:

The onset of job strain predicted the onset of subsequent insomnia symptoms after adjustment for sex, age, marital status, education, smoking, physical activity, alcohol consumption, body mass index, and comorbidities (odds ratio compared to no onset of job strain 1.32, 95% CI 1.16–1.51). The disappearance of job strain was associated with lower odds of repeated insomnia symptoms (odds ratio compared to no disappearance of job strain 0.78, 95% CI 0.65–0.94). Further adjustment for shift work or sleep apnea did not change these associations.

Conclusions:

These results suggest that job strain is a modifiable risk factor for insomnia symptoms.

Occupational Social Class and Personality Traits in Relation to Leisure-Time Physical Activity Level: Cross-Sectional Results From the Copenhagen Aging and Midlife Biobank

OBJECTIVE

To investigate separate and combined associations of occupational social class and personality traits with late midlife leisure-time physical activity duration and intensity.

METHOD

Cross-sectional data from the Copenhagen Aging and Midlife Biobank ( N = 4,649) were analyzed using linear regression models with leisure-time physical activity (metric equivalence) as outcome.

RESULTS

Low versus high occupational social class was associated with 4% (95% confidence interval [CI] = [3%, 5%]) greater leisure-time physical activity duration, but 2% (CI = [1%, 3%]) lower intensity. Each 10-unit increase in extraversion was associated with 5% (CI = [2%, 8%]) greater duration. Intensity increased by each 10-unit increase in conscientiousness (6%, CI = [4%, 7%]), openness (3%, CI = [1%, 4%]), neuroticism (3%, CI = [1%, 4%]), and extraversion (5%, CI = [4%, 7%]). Conscientiousness was positively associated with duration in low, but not in high, occupational social class (interaction p value = .002).

DISCUSSION

Higher occupational social class was associated with lower leisure-time physical activity duration, but higher intensity. Extraversion was positively associated with duration and intensity. Conscientiousness, openness, and neuroticism were positively associated with intensity. Overall, interactions were not consistent.

Metabolically Healthy Obesity and Ischemic Heart Disease: A 10-Year Follow-Up of the Inter99 Study

CONTEXT

Recent studies have suggested that a subgroup of obese individuals is not at increased risk of obesity-related complications. This subgroup has been referred to as metabolically healthy obese.

OBJECTIVE

To investigate whether obesity is a risk factor for development of ischemic heart disease (IHD) irrespective of metabolic health.

DESIGN

In all, 6238 men and women from the Danish prospective Inter99 study were followed during 10.6 (standard deviation = 1.7) years.

SETTING

General community.

PARTICIPANTS

Participants were classified according to body mass index and four metabolic risk factors (low high-density lipoprotein cholesterol, elevated blood pressure, triglycerides, and fasting plasma glucose). Metabolically healthy individuals were defined as having no metabolic risk factors, and metabolically unhealthy individuals were defined as having a minimum of one.

MAIN OUTCOME MEASURES

IHD.

RESULTS

During follow-up, 323 participants developed IHD. Metabolically healthy obese men had increased risk of IHD compared with metabolically healthy normal-weight men [hazard ratio (HR), 3.1; 95% confidence interval (CI), 1.1 to 8.2)]. The corresponding results for women were less pronounced (HR, 1.8; 95% CI, 0.7 to 4.8). Being metabolically healthy but overweight was not associated with higher risk of IHD in men (HR, 1.1; 95% CI, 0.5 to 2.4), and in women the risk was only slightly increased and insignificant (HR, 1.5; 95% CI, 0.8 to 3.0). A substantial proportion of metabolically healthy individuals became metabolically unhealthy after 5 years of follow-up. When these changes in exposure status were taken into account, slightly higher risk estimates were found.

CONCLUSIONS

Being obese is associated with higher incidence of IHD irrespective of metabolic status, and we question the feasibility of denoting a subgroup of obese individuals as metabolically healthy.

Informal caregiving as a risk factor for type 2 diabetes in individuals with favourable and unfavourable psychosocial work environments: A longitudinal multi-cohort study

AIM

To examine whether informal caregiving is associated with increased risk of type 2 diabetes (T2D), and whether job strain and social support at work modify the association.

METHODS

Individual participant's data were pooled from three cohort studies-the French GAZEL study, the Swedish Longitudinal Occupational Survey of Health (SLOSH) and the British Whitehall II study-a total of 21,243 study subjects. Informal caregiving was defined as unpaid care for a closely related person. Job strain was assessed using the demand-control model, and questions on co-worker and supervisor support were combined in a measure of social support at work. Incident T2D was ascertained using registry-based, clinically assessed and self-reported data.

RESULTS

A total of 1058 participants developed T2D during the up to 10 years of follow-up. Neither informal caregiving (OR: 1.09, 95% CI: 0.92-1.30) nor high job strain (OR: 1.04, 95% CI: 0.86-1.26) were associated with T2D risk, whereas low social support at work was a risk factor for T2D (OR: 1.18, 95% CI: 1.02-1.37). Also, informal caregivers who were also exposed to low social support at work were at higher risk of T2D (OR: 1.40, 95% CI: 1.08-1.82) compared with those who were not informal caregivers and had high social support at work (multiplicative test for interaction, P=0.04; additive test for interaction, synergy index=10).

CONCLUSION

Informal caregiving was not independently associated with T2D risk. However, low social support at work was a risk factor, and informal caregivers with low social support at work had even higher risks of T2D.

Risk of depressive disorder following disasters and military deployment: systematic review with meta-analysis

BACKGROUND

Numerous studies describe the occurrence of post-traumatic stress disorder following disasters, but less is known about the risk of major depression.

AIMS

To review the risk of depressive disorder in people surviving disasters and in soldiers returning from military deployment.

METHOD

A systematic literature search combined with reference screening identified 23 controlled epidemiological studies. We used random effects models to compute pooled odds ratios (ORs).

RESULTS

The average OR was significantly elevated following all types of exposures: natural disaster OR = 2.28 (95% CI 1.30-3.98), technological disaster OR = 1.44 (95% CI 1.21-1.70), terrorist acts OR = 1.80 (95% CI 1.38-2.34) and military combat OR = 1.60 (95% CI 1.09-2.35). In a subset of ten high-quality studies OR was 1.41 (95% CI 1.06-1.87).

CONCLUSIONS

Disasters and combat experience substantially increase the risk of depression. Whether psychological trauma per se or bereavement is on the causal path is unresolved.

Lifestyle, family history, and risk of idiopathic Parkinson disease: a large Danish case-control study

The relationship between Parkinson disease (PD) and smoking has been examined in several studies, but little is known about smoking in conjunction with other behaviors and a family history of PD. Using unconditional logistic regression analysis, we studied individual and joint associations of these factors with idiopathic PD among 1,808 Danish patients who were diagnosed in 1996-2009 and matched to 1,876 randomly selected population controls. Although there was a downward trend in duration of smoking, this was not observed for daily tobacco consumption. A moderate intake of caffeine (3.1-5 cups/day) was associated with a lower odds ratio for PD (0.45, 95% confidence interval: 0.34, 0.62), as was a moderate intake of alcohol (3.1-7 units/week) (odds ratio = 0.60, 95% confidence interval: 0.58, 0.84); a higher daily intake did not reduce the odds further. When these behaviors were studied in combination with smoking, the odds ratios were lower than those for each one alone. Compared with never smokers with no family history of PD, never smokers who did have a family history had an odds ratio of 2.81 (95% confidence interval: 1.91, 4.13); for smokers with a family history, the odds ratio was 1.60 (95% confidence interval: 1.15, 2.23). In conclusion, duration of smoking seems to be more important than intensity in the relationship between smoking and idiopathic PD. The finding of lower risk estimates for smoking in combination with caffeine or alcohol requires further confirmation.

Distance to high-voltage power lines and risk of childhood leukemia--an analysis of confounding by and interaction with other potential risk factors

We investigated whether there is an interaction between distance from residence at birth to nearest power line and domestic radon and traffic-related air pollution, respectively, in relation to childhood leukemia risk. Further, we investigated whether adjusting for potential confounders alters the association between distance to nearest power line and childhood leukemia. We included 1024 cases aged <15, diagnosed with leukemia during 1968-1991, from the Danish Cancer Registry and 2048 controls randomly selected from the Danish childhood population and individually matched by gender and year of birth. We used geographical information systems to determine the distance between residence at birth and the nearest 132-400 kV overhead power line. Concentrations of domestic radon and traffic-related air pollution (NOx at the front door) were estimated using validated models. We found a statistically significant interaction between distance to nearest power line and domestic radon regarding risk of childhood leukemia (p = 0.01) when using the median radon level as cut-off point but not when using the 75th percentile (p = 0.90). We found no evidence of an interaction between distance to nearest power line and traffic-related air pollution (p = 0.73). We found almost no change in the estimated association between distance to power line and risk of childhood leukemia when adjusting for socioeconomic status of the municipality, urbanization, maternal age, birth order, domestic radon and traffic-related air pollution. The statistically significant interaction between distance to nearest power line and domestic radon was based on few exposed cases and controls and sensitive to the choice of exposure categorization and might, therefore, be due to chance.

Psychosocial risk factors, pre-motor symptoms and first-time hospitalization with Parkinson's disease: a prospective cohort study

BACKGROUND AND PURPOSE

Experimental studies support a link between stress and development of parkinsonian symptoms, but prospective population studies are lacking. The aim of the current study is to determine the effects of several psychosocial factors on the risk of Parkinson's disease (PD), as well as to identify potential pre-motor symptoms for PD in a large prospective cohort study.

METHODS

In 1991-1993, a total of 9955 women and men free of PD from the Copenhagen City Heart Study were asked about major life events, economic hardship, social network, impaired sleep and vital exhaustion. The participants were followed for first-time hospitalization with PD in nationwide registers until 2011.

RESULTS

Vital exhaustion was associated with a higher risk of PD hospitalization in an exposure-dependent manner (P(trend) = 0.001), with high vs. low vital exhaustion being associated with a hazard ratio of 2.50 [95% confidence interval (CI): 1.28-4.89]. A slightly higher risk of PD hospitalization (hazard ratio = 1.49; 95% CI: 0.87-2.56) was suggested in participants with impaired sleep at baseline. No more than weak associations were observed for economic hardship, major life events or inadequate social network in the current study.

CONCLUSIONS

Overall, the hypothesis that psychosocial risk factors affect the risk of PD is not supported. The results, however, suggest that vital exhaustion may be a pre-motor marker of the neurodegenerative process eventually leading to motor symptoms and clinical PD. Vital exhaustion may be useful for screening aimed at early detection and when considering disease-modifying therapies in people at high risk of clinical PD.

Negative aspects of close social relations and 10-year incident ischaemic heart disease hospitalization among middle-aged Danes

BACKGROUND

Little is known about the association between negative aspects of close social relations and development of ischaemic heart disease (IHD). We aim to address if the experience of worries/demands and conflicts with close social relations are related to risk of first-time hospitalization with IHD and whether emotional support can buffer this effect.

METHODS

A total of 8550 randomly selected men and women aged 36-52 years free of earlier IHD hospitalization at baseline in 2000 were followed prospectively for first-time hospitalization with IHD (ICD10: I21-25) through 2010 in the Danish National Patient Registry. Cox regression analysis was used to analyse data and all analyses were adjusted for age, gender, social class, cohabitation, and depressive symptoms.

RESULTS

Worries/demands from and conflicts with children were associated with IHD hospitalization in an exposure-dependent manner (p-trends 0.0001 and 0.03) with twice the risk among those most highly exposed, HRworries/demands = 2.05 (95% CI 0.91-4.54) and HRconflicts=1.90 (95% CI 1.00-3.61). 'Always' experiencing worries/demands from partner was also associated with a nearly twice the risk of IHD, whereas no association was found for conflicts with partner. High levels of worries/demands from or conflicts with family and friends were associated with a 40% higher risk of IHD.

CONCLUSIONS

Negative aspects of close social relations are associated with higher risk of incident IHD hospitalization except for conflicts with partner. We found no clear evidence of a buffering effect of emotional support.

Major life events and development of major depression in Parkinson's disease patients

BACKGROUND AND PURPOSE

Non-motor symptoms including depression are important features of Parkinson's disease (PD). We aim to address the relationship between major life events and depression amongst PD patients free of depressive symptoms at baseline.

METHODS

New-onset PD patients from California were recruited in 2001-2007 and followed up for 3-4 years. The participants (n=221) were examined by neurologists and responded to comprehensive interviews that included major life events, social support, and coping measures from validated scales. Major depression was assessed using the Structured Clinical Interview for the DSM-IV depression module (SCID).

RESULTS

More than half of all patients had experienced major life events since diagnosed with PD, and 22 patients developed a major depression. The number of life events was associated with risk of depression in an exposure-dependent manner, with each additional event being associated with a 56% higher risk of depression (95% CI: 1.23-1.98). Most individual life events were associated with a two- to eight-fold higher risk of depression. Patients with low social support or coping capacities seemed to be particularly susceptible to developing depression after experiencing major life events.

CONCLUSIONS

Life events play an important role for onset of depression in patients with PD; an effect that seems to be modulated by social support and coping capacities and these factors may therefore be important to assess in order to identify patients with PD at high risk of depression and provide effective interventions.

Perceived stress and risk of adult-onset asthma and other atopic disorders: a longitudinal cohort study

BACKGROUND

Psychological stress can affect airway inflammatory response to irritants and allergens, but the importance of stress in the etiology of adult-onset respiratory and dermatologic allergic disorders remains unclear. We aim to address the relationship between perceived stress and the risk of adult-onset asthma, allergic rhinitis, atopic dermatitis, and asthma/bronchitis medication.

METHODS

Participants (n = 9785) from the Copenhagen City Heart Study, Denmark, free of atopic disorders at baseline in 1981-1983 were asked questions on stress intensity and frequency. They were followed for first-time asthma hospitalization in nationwide registers until 2010, with < 0.1% loss to follow-up. Objective measures of lung function allowed for thorough adjustment for confounding and prevented ambiguity between diagnosis of asthma and chronic obstructive lung disease. Daily intake of asthma/bronchitis medication and incidence of asthma, allergic rhinitis, and atopic dermatitis were assessed by self-report after 10 years of follow-up in 5648 persons.

RESULTS

Perceived stress was associated with atopic disorders in a dose-dependent manner (P(trend)  < 0.001). High vs low stress was associated with higher risk of self-reported asthma incidence (OR = 2.32; 95% CI: 1.47-3.65), daily intake of asthma/bronchitis medication (OR = 2.26; 95% CI: 1.42-3.58), first-time asthma hospitalization (HR = 2.01; 95% CI: 1.41-2.86), allergic rhinitis (OR = 1.64; 95% CI: 0.99-2.72), and atopic dermatitis (OR = 1.75; 95% CI: 1.11-2.77). The associations were similar for smokers and nonsmokers.

CONCLUSIONS

Stress is strongly associated with asthma incidence and hospitalization, use of asthma medication as well as with allergic rhinitis and atopic dermatitis in adults.

Quantifying mediating effects of endogenous estrogen and insulin in the relation between obesity, alcohol consumption, and breast cancer

BACKGROUND

Increased exposure to endogenous estrogen and/or insulin may partly explain the relationship of obesity, physical inactivity, and alcohol consumption and postmenopausal breast cancer. However, these potential mediating effects have not been formally quantified in a survival analysis setting.

METHODS

We combined data from two case-cohort studies based in the Women's Health Initiative-Observational Study with serum estradiol levels, one of which also had insulin levels. A total of 1,601 women (601 cases) aged 50 to 79 years who were not using hormone therapy at enrollment were included. Mediating effects were estimated by applying a new method based on the additive hazard model.

RESULTS

A five-unit increase in body mass index (BMI) was associated with 50.0 [95% confidence interval (CI), 23.2-76.6] extra cases per 100,000 women at-risk per year. Of these, 23.8% (95% CI, 2.9-68.4) could be attributed to estradiol and 65.8% (95% CI, 13.6-273.3) through insulin pathways. The mediating effect of estradiol was greater (48.8%; 95% CI, 18.8-161.1) for BMI when restricted to estrogen receptor positive (ER(+)) cases. Consuming 7+ drinks/wk compared with abstinence was associated with 164.9 (95% CI, 45.8-284.9) breast cancer cases per 100,000, but no significant contribution from estradiol was found. The effect of alcohol on breast cancer was restricted to ER(+) breast cancers.

CONCLUSIONS

The relation of BMI with breast cancer was partly mediated through estradiol and, to a greater extent, through insulin.

IMPACT

The findings provide support for evaluation of interventions to lower insulin and estrogen levels in overweight and obese postmenopausal women to reduce breast cancer risk.

Loss of partner and breast cancer prognosis - a population-based study, Denmark, 1994-2010

BACKGROUND

The extent to which experiencing a stressful life event influences breast cancer prognosis remains unknown, as the findings of the few previous epidemiological studies are inconsistent. This large population-based study examines the association between a common major life event, loss of a partner and breast cancer recurrence and all-cause mortality.

METHODS

N=21,213 women diagnosed with a first primary breast cancer 1994-2006, who had a cohabiting partner in the 4 years before their breast cancer diagnosis, were followed for death and recurrence in population-based registers and clinical databases. Information on education, disposable income, comorbidity and prognostic risk factors were included in Cox regression analyses.

RESULTS

Women who had lost a partner either before diagnosis or in subsequent years were not at significantly higher risk of recurrence or dying than women who had not lost a partner.

CONCLUSION

Our results do not support the concern that experiencing a stressful life event, the loss of a partner, negatively affects prognosis of breast cancer.