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Objective To investigate the separate and combined effects of overall heavy physical workload (PWL) and low decision authority on all-cause disability pension (DP) or musculoskeletal DP. Methods This study uses a sample of 1,804,242 Swedish workers aged 44–63 at the 2009 baseline. Job Exposure Matrices (JEMs) estimated exposure to PWL and decision authority. Mean JEM values were linked to occupational codes, then split into tertiles and combined. DP cases were taken from register data from 2010 to 2019. Cox regression models estimated sex-specific Hazard Ratios (HR) with 95% confidence intervals (95% CI). The Synergy Index (SI) estimated interaction effects. Results Heavy physical workload and low decision authority were associated with an increased risk of DP. Workers with combined exposure to heavy PWL and low decision authority often had greater risks of all-cause DP or musculoskeletal DP than when adding the effects of the single exposures. The results for the SI were above 1 for all-cause DP (men: SI 1.35 95%CI 1.18–1.55, women: SI 1.19 95%CI 1.05–1.35) and musculoskeletal disorder DP (men: SI 1.35 95%CI 1.08–1.69, women: 1.13 95%CI 0.85–1.49). After adjustment, the estimates for SI remained above 1 but were not statistically significant. Conclusion Heavy physical workload and low decision authority were separately associated with DP. The combination of heavy PWL and low decision authority was often associated with higher risks of DP than would be expected from adding the effects of the single exposures. Increasing decision authority among workers with heavy PWL could help reduce the risk of DP.

Objectives The aim of the study was to examine the associations between heavy physical workload among middle-aged and older workers and disability pension due to any diagnosis, as well as musculoskeletal, psychiatric, cardiovascular or respiratory diagnoses. The population-based design made it possible to examine dose–response and potential gender differences in the associations. Methods About 1.8 million men and women aged 44–63 years and registered as living in Sweden in 2005 were followed regarding disability pension during 2006–2016, until ages 55–65 years. Mean values of physical workload and job control, estimated through gender-specific job-exposure matrices (JEMs), were assigned to individuals through their occupational titles in 2005. Exposure values were ranked separately for women and men and divided into quintiles. Associations were analyzed with Cox proportional-hazards regression. Results The analyses showed robust, dose–response associations between physical workload and disability pension with a musculoskeletal diagnosis in both genders: the adjusted hazard ratio and 95% confidence interval for those with the heaviest exposure was 2.58 (2.37–2.81) in women and 3.34 (2.83–3.94) in men. Dose–response associations were also seen in relation to disability pension with a cardiovascular or a respiratory diagnosis, though the hazard ratios were smaller. Physical workload was not associated with disability pension with a psychiatric diagnosis after adjustment for job control. Conclusion This study of the entire Swedish population of middle-aged and older workers suggests that higher degrees of physical workload may increase the risk of disability pension overall, and specifically with musculoskeletal, cardiovascular or respiratory diagnosis, in both women and men.

Background The present study aims to investigate the association between educational qualification and early labor market exit among men and to examine the contribution of labor market marginalization measured across the working life on this association. Method A register-linked cohort study was conducted including men who completed military service in 1969/70 (born between 1949 and 1951) and were alive at age 55 and not disability pension beneficiaries (n = 40 761). Information on the highest level of educational qualification and the outcome of early exit (disability pension, sickness absence, unemployment, and early old-age pension) was obtained from Swedish nationwide registers between the ages of 55 and 64 years. Labor market marginalization was defined as periods of long-term unemployment and sickness absence over the working life and up to follow-up. Cox regression analyses were used to obtain hazard ratios (HR) with 95% confidence intervals (CI). Results Low-educated men were more likely to leave the labor force early due to disability pension or sickness absence (HR: 2.48), unemployment (HR: 2.09), and early old-age pension with- (HR:1.25) and without -income (HR: 1.58). Labor market marginalization across the working life explained a large part of the association for the more involuntary early exit routes (disability pensions, sickness absence, unemployment) and explained very little with regards to the more voluntary early exit routes (early old-age pension with and without income). Conclusion Exposure to labor market marginalization across the working life was important in explaining educational differences in early labor market exit due to disability pension or sickness absence and unemployment. This study underscores the importance of identifying and implementing preventive measures in the workplace (e.g. adaptions) to prevent new spells of sickness absence and unemployment, especially among low educated individuals.

Introduction Body mass index (BMI) is a composite variable of weight and height, often used as a predictor of health outcomes, including mortality. The main purpose of combining weight and height in one variable is to obtain a measure of obesity independent of height. It is however unclear how accurate BMI is as a predictor of mortality compared with models including both weight and height or a weight × height interaction as predictors. Methods The current study used conscription data on weight, height, and BMI of Swedish men (N = 48,904) in 1969/70 as well as linked data on mortality (3442 deaths) between 1969 and 2008. Cox proportional hazard models including combinations of weight, height, and BMI at conscription as predictors of subsequent all‐cause and cause‐specific mortality were fitted to data. Results An increase by one standard deviation on weight and BMI were associated with an increase in hazard for all‐cause mortality by 5.4% and 11.5%, respectively, while an increase by one standard deviation on height was associated with a decrease in hazard for all‐cause mortality by 9.4%. The best‐fitting model indicated lowest predicted all‐cause mortality for those who weighed 60.5 kg at conscription, regardless of height. Further analyses of cause‐specific mortality suggest that this weight seems to be a compromise between lower optimal weights to avoid cancer and CVD mortality and a higher optimal weight to not die by suicide. Conclusions According to the present findings, there are several ways to make better use of measured weight and height than to calculate BMI when predicting mortality.

Background Psychosocial workplace factors may be associated with alcohol-related morbidity, but previous studies have had limited opportunities to take non-occupational explanatory factors into account. The aim of this study is to investigate associations between job control, job demands and their combination (job strain) and diagnosed alcohol-related morbidity while accounting for several potentially confounding factors measured across the life-course, including education. Methods Job control, job demands and job strain were measured using the Swedish job exposure matrix measuring psychosocial workload on the occupational level linked to over 3 million individuals based on their occupational titles in 2005 and followed up until 2016. Cox regression models were built to estimate associations with alcohol-related diagnoses recorded in patient registers. Results Low job control was associated with an increased risk of alcohol-related morbidity, while high job demands tended to be associated with a decreased risk. Passive and high-strain jobs among men and passive jobs among women were also associated with an increased risk of alcohol diagnoses. However, all associations were found to be weakened in models adjusted for other factors measured prospectively over the life-course, especially in models that included level of education. Conclusion The associations between low job control and high job demands, and the risk of alcohol-related morbidity reflect underlying socioeconomic differences to some extent. Lower job control, however, remained associated with a higher risk of alcohol-related morbidity.

Background Some studies have suggested that teachers are particularly at risk for mental health problems but the research in this area has not been conclusive. This study aims to compare the risk of being diagnosed with depression for different types of teachers in Sweden, both with each other and with the rest of the population, using register data. Methods Just over 3 million individuals age 30-60 were included of which 256,166 were teachers. The exposure variable was the occupation held in 2005 and the outcome was any diagnosis of depression during the follow up period of 2006 to 2016. The data was analyzed using Cox proportional hazard regression. Results Around 5 % of women and 3 % of men developed depression during the follow up. For women, teachers had a decreased risk of developing depression compared to non-teachers, but this association was no longer present after adjusting for common covariates including education. For men, teachers had an increased risk of depression both before and after adjustment (HR 1.27 95% CI 1.22-1.32). When comparing different kinds of teachers to university teachers, several types of teachers including primary and special education teachers had an increased risk among men while primary and secondary teachers had a decreased risk among women. Conclusion The increased risk of depression in male teachers is a result that requires further exploration in terms of occupational differences between male and female teachers.

ObjectiveTo investigate the association between job control, job demands and their combination (job strain) and suicide attempts and deaths among male and female workers in Sweden.MethodsJob control and demands were measured separately for men and women using a job exposure matrix, which was linked to around three million individuals based on their occupational title in 2005. Suicide attempts and deaths were measured in the hospital and cause of death registers from 2006 to 2016. HRs were estimated using discrete proportional hazards models with annually updated age as the time axis. Models were adjusted for sociodemographic, family, health, labour market and childhood factors, as well as the time-varying effects of unemployment, sick leave and family factors during follow-up.ResultsLow job control was associated with an increased risk of suicide attempts and deaths among both men and women while high job demands tended to be associated with a decreased risk. The combination of job control and job demands (job strain) reflected the increased risk of low control jobs and the decreased risk of high demand jobs. Associations were attenuated but still present after adjustments.ConclusionsLow job control is related to suicide attempts and deaths, and this is only partially explained by important covariates measured both prebaseline and during follow-up. Attempts to increase job control among workers may be beneficial in preventing suicide.

Introduction The EPHOR project is constructing a mega cohort for pooled analysis of data from multiple European cohort studies of occupation and health. The objective is to provide new evidence of the impact of occupational exposures on the risk of major non-communicable diseases, through systematic and agnostic analyses across the life-course. Materials and Methods Cohorts are registered in an online inventory. Cohort data and occupational information are being harmonised and documented in an online variable catalogue, and will be linked with a newly developed European Job-Exposure Matrix (EuroJEM) characterising multiple: chemical and particle, ergonomic, physical, and psychosocial exposures and precariousness. Cohort information on working time will also be harmonised. Knowledge gaps on occupational exposures in relation to major non-communicable diseases were identified. Both meta-analysis and decentralized analysis approaches will be used, as appropriate. Ethics approval is provided by all relevant committees. Results Currently 29 European cohorts covering a broad range of countries as well as multi-country studies are participating, containing more than 20 million participants. Cohort designs range from smaller scale studies including hundreds to thousands of workers with detailed exposure and/or outcome characterisation, to large-scale general population cohorts including multiple millions of participants with occupational information captured using registry-based methods. Cohorts were largely established and followed-up during the 2000s through the current time, though some were established earlier. Occupational information primarily entails the working lifetime or follow-up period. Outcome information includes disease incidence, disability, and mortality. In some studies, information about genetics, epigenetics, other biomarkers and clinical/functional evaluations is available. Analysis will address knowledge gaps of cancer, respiratory, cardiovascular/metabolic, and neurodegenerative diseases, mental and musculoskeletal disorders, and work participation. Conclusions We expect the mega cohort will be a useful long-term resource to study relationships of occupations, work-related exposures and health in Europe to inform policy and prevention.

Background Earlier research has identified both synergistic and compensatory personality traits by intelligence interaction effects on academic performance. Methods The present study employed data on intelligence, personality traits, and academic performance in the 1997 National Longitudinal Survey of Youth (NLSY97, N = 8984). Results Some intelligence by personality trait interaction effects, mainly involving indicators of dependability, on high school grades were identified. The interaction effects tended to be synergistic, meaning that the association between the trait and grades tended to strengthen with increased intelligence. A positive association between intelligence and the reliability in the measurement of a dependability composite score accounted for a substantial portion of the synergistic dependability by intelligence interaction effect on academic performance. Conclusions Personality trait by intelligence interaction effects on academic performance tend to be synergistic and may, at least to some degree, be due to a positive association between intelligence and reliability in the measurement of personality traits.

To assess the risk of disability and early-age retirement associated with previous long-term sickness absence for back pain (back-pain SA), exposure to high physical workload, low job control, high demands and high strain, and to evaluate effect modification by work factors on the relationship between back-pain SA and premature retirement.All employed Swedish residents born 1946-1955 (n = 835,956) were followed up from 2010 to 2016 for disability (DP) and early-age pension (EAP). Associations of premature retirement with exposure to work factors and back-pain SA in the 3 years before follow-up were estimated through proportional hazards models. Retirement, back-pain SA and covariates were assessed through administrative sources, and exposure to work factors through a job-exposure matrix.In both genders, back-pain SA was associated with DP ( 1 episode: HR 3.23 among men; HR 3.12 among women) and EAP ( 1 episode: HR 1.24 among men; HR 1.18 among women). Higher physical workload and lower job control were also associated with an increased DP risk in both genders, whereas higher job demands showed a decreased risk. For EAP, associations with work factors were weak and inconsistent across genders. No effect modification by work factors was found, except for a negative effect modification by job strain on DP risk among women, i.e. a reduced effect of back-pain SA with increasing exposure.Back-pain SA was a significant predictor of both DP and EAP, while work factors were consistently associated only with DP. Our results indicate that the joint effect of back-pain SA and work factors on DP is additive and does not support effect modification by work factors.

We identified occupations with a high incidence of prolonged sickness absence (SA) in Nordic employees and explored similarities and differences between the countries. Utilizing data from national registers on 25–59-year-old wage-earners from Denmark, Finland, Norway and Sweden, we estimated the gender- and occupation-specific age-adjusted cumulative incidence of SA due to any cause, musculoskeletal diseases and mental disorders. To increase the comparability of occupations between the countries, we developed a Nordic crosswalk for occupational codes. We ranked occupational groups with the incidence of SA being statistically significantly higher than the population average of the country in question and calculated excess fractions with the employee population being the reference group. We observed considerable occupational differences in SA within and between the countries. Few occupational groups had a high incidence in all countries, particularly for mental disorders among men. In each country, manual occupations typically had a high incidence of SA due to any cause and musculoskeletal diseases, while service occupations had a high incidence due to mental disorders. Preventive measures targeted at specific occupational groups have a high potential to reduce work disability, especially due to musculoskeletal diseases. Particularly groups with excess SA in all Nordic countries could be at focus.

Background Cognitive ability and socioeconomic background (SEB) have been previously identified as determinants of achieved level of education. According to a “discrimination hypothesis”, higher cognitive ability is required from those with lower SEB in order to achieve the same level of education as those with higher SEB. Support for this hypothesis has been claimed from the observation of a positive association between SEB and achieved level of education when adjusting for cognitive ability. We propose a competing hypothesis that the observed association is due to residual confounding. Methods To adjudicate between the discrimination and the residual confounding hypotheses, data from the 1997 National Longitudinal Survey of Youth (NLSY97, N = 8984) was utilized, including a check of the logic where we switched predictor and outcome variables. Results The expected positive association between SEB and achieved level of education when adjusting for cognitive ability (predicted by both hypotheses) was found, but a positive association between cognitive ability and SEB when adjusting for level of education (predicted only by the residual confounding hypothesis) was also observed. Conclusions These results highlight the potential use of reversing predictors and outcomes to test the logic of hypothesis testing, and support a residual confounding hypothesis over a discrimination hypothesis in explaining associations between SEB, cognitive ability, and educational outcome.

The effect of higher education on intelligence has been examined through analyses of longitudinal data. Such studies typically have found a positive effect on the order of 1 IQ point per year of higher education in analyses where pre-education intelligence was included as a covariate. Unfortunately, this statistical technique is known to yield positively biased results if the covariate has measurement errors and is correlated with the predictor. At the same time, a negative bias arises if the intelligence measure after higher education has a ceiling effect, as in data from the 1970 British Cohort Study that were used in a recent study on the effect of higher education. Here, we develop a method that combines mathematical analysis and simulations to account for both aspects of limited reliability of intelligence measures. When we apply this method in a reanalysis of the data from the 1970 British Cohort Study, we find that the estimated effect of higher education is reduced to 0.4 IQ points per year. We also find that the effect of higher education appears to be somewhat larger in the first two years of higher education, consistent with diminishing marginal cognitive benefits of education.

BackgroundBoth low intelligence and low emotional control have previously been linked to a higher risk of suicide, but it is unknown whether the associations apply consistently over the life course.MethodsThe study was based on data on intelligence and emotional control, collected from 48 738 Swedish men conscripted in 1969–1970, at ages 18–20 years. The data were linked to national registers giving information on subsequent suicidal behavior (completed and attempted suicide) up to the age of 59 years. The associations were investigated using logistic regression and Cox proportional hazards regression models, with adjustment for childhood socioeconomic status.ResultsIntelligence and emotional control assessed in late adolescence both showed robust inverse associations with suicidal behavior over the 38-year follow-up. However, while the association between lower intelligence and higher rate of suicidal behavior remained the same throughout (~40% increased hazard per unit on a five-level scale), the association between lower emotional control and suicidal behavior was substantially stronger in early adulthood (~100% increased hazard per unit) than in late middle age (~30% increased hazard per unit).ConclusionsThe study adds to previous research by showing that the association between poor emotional control and subsequent suicide risk in men becomes weaker over the life course, while the association between low intelligence and suicide risk seems to be constant. The particularly high suicide risk of young men with poor emotional control may motivate targeted prevention efforts.

Earlier research has identified personality traits × intelligence interaction effects on academic performance. The present study, employing data from the 1997 National Longitudinal Survey of Youth (NLSY97, N = 8984), identified some interaction effects, mainly involving indicators of dependability, on high school grades. The interaction effects tended to be synergistic, meaning that the association between the trait and grades tended to strengthen with increased intelligence. This could be due to a sufficient level of intelligence being necessary for higher grades, and that lack thereof cannot be compensated for by a high degree of some advantageous personality trait. However, a positive association between intelligence and reliability in the measurement of personality, as well as a reversed causal effect of grades on self-rated personality moderated by intelligence, could also be contributing causes to the tendency for synergistic interaction effects.

BackgroundHigh job demands, low job control, and their combination (job strain) may increase workers' risk of depression. Previous research is limited by small populations, not controlling for previous depression, and relying on the same informant for reporting exposure and outcome. This study aims to examine the relationship between objectively measured workplace factors and the risk of developing clinical depression among the Swedish working population while controlling for previous psychiatric diagnoses and sociodemographic factors.MethodsControl, demands, and job strain were measured using the Swedish Job Exposure Matrix (JEM) measuring psychosocial workload linked to around 3 million individuals based on their occupational titles in 2005. Cox regression models were built to estimate associations between these factors and diagnoses of depression recorded in patient registers.ResultsLower job control was associated with an increased risk of developing depression (HR 1.43, 95% CI 1.39–1.48 and HR 1.27, 95% CI 1.24–1.30 for men and women with the lowest control, respectively), and this showed a dose–response relationship among men. Having high job demands was associated with a slight decrease in depression risk for men and women. High strain and passive jobs (both low control jobs) were associated with an increased risk of depression among men, and passive jobs were associated with an increased risk among women.ConclusionHigh job control appears important for reducing the risk of developing depression even when accounting for previous psychiatric diagnoses and sociodemographic factors. This is an important finding concerning strategies to improve occupational and in turn mental health.

Poor academic performance in childhood is associated with suicide attempt in adulthood, but the mechanisms are not known. We investigated educational attainment as a possible pathway.We followed two sets of cohorts, born around 1950/1970, respectively, in the Swedish population-representative 'Evaluation Through Follow-up' study for a first suicide attempt in national records up to 2013. Data on grade point average (GPA) at age 13/16 and educational attainment (years of schooling) in adulthood were used. The path models included linear and Cox proportional hazards regressions. A model with matched age range during follow-up was used to compare the cohorts.In the 1970 cohort, the association between GPA and suicide attempt between age 26 and 46 was partly mediated by attained education (total association, β=-0.82; via education: -0.29, per SD increase in GPA), but GPA also had a direct path to suicide attempt (β=-0.53). There was no evidence of such a pathway in the 1950 cohort between age 41 and 65. In the age-matched analysis, at age 26-46, the association between GPA and suicide attempt was stronger in the 1970 cohort compared to the 1950 cohort (β=-0.72 and -0.24, respectively).Differences in attained education seem to partly explain the associations of academic performance with suicide attempt up to middle age. Furthermore, there is some indication that academic performance may have become more important for young people's mental health than it was in previous generations.

BMI has been used as a predictor of health outcomes, including mortality, in numerous studies. However, in the present study of Swedish male conscripts with follow ups (N = 48,904, 3442 deaths), we show that there are several better ways to use measured weight and height than to calculate BMI when predicting mortality. The most accurate model indicated lowest predicted all-cause mortality for those who weighed 60.5 kg at conscription, regardless of height. This weight seems to be a compromise between lower optimal weights to avoid cancer and CVD mortality and a higher optimal weight to avoid suicide.

We examined the associations between fathers’ alcohol consumption and total and cause-specific mortality in adult offspring. Fathers’ alcohol consumption was associated with increased risk of alcohol-related mortality in offspring. The association appeared to be weaker for causes of death in which alcohol plays a smaller, or less direct, role., Aim This study examined associations between fathers’ alcohol consumption and risk for total and cause-specific mortality in offspring. Short summary We examined the associations between fathers’ alcohol consumption and total and cause-specific mortality in adult offspring. Fathers’ alcohol consumption was associated with increased risk of alcohol-related mortality in offspring. The association appeared to be weaker for causes of death in which alcohol plays a smaller, or less direct, role. Methods Data on fathers’ alcohol consumption, and offspring’s risky use of alcohol, smoking, mental health and contact with police/childcare authorities were collected among 46,284 men (sons) aged 18–20 years, during conscription for compulsory military training in 1969/70. Data on offspring mortality were obtained from the National Cause of Death register, 1971–2008. The mortality outcomes included total mortality, alcohol-related causes of death and violent causes of death (categorized into suicides vs violent/external causes excluding suicides). Results Compared to sons whose fathers never used alcohol, the risk for total and alcohol-related mortality among sons increased with the father’s consumption level. The risk of violent death was significantly elevated among sons whose fathers drank alcohol occasionally or often, but the risk of suicide increased in the highest consumption category only. After adjustment for covariates, the results remained for alcohol-related mortality whereas they were significantly attenuated, or disappeared, for total mortality, violent death and suicide. Conclusions Fathers’ alcohol consumption is associated with increased risk of alcohol-related mortality in the offspring. Alcohol use among fathers also increases the offspring’s risk of later total mortality, suicide and violent death, but these associations appear to be mediated or confounded by factors related to parental drinking and/or adverse childhood psychosocial circumstances.

Background Both low intelligence and low emotional control have previously been linked to a higher risk of suicide, but it is unknown whether the associations apply consistently over the life course. Methods The study was based on data on intelligence and emotional control, collected from 48 738 Swedish men conscripted in 1969–1970, at ages 18–20 years. The data were linked to national registers giving information on subsequent suicidal behavior (completed and attempted suicide) up to the age of 59 years. The associations were investigated using logistic regression and Cox proportional hazards regression models, with adjustment for childhood socioeconomic status. Results Intelligence and emotional control assessed in late adolescence both showed robust inverse associations with suicidal behavior over the 38-year follow-up. However, while the association between lower intelligence and higher rate of suicidal behavior remained the same throughout (~40% increased hazard per unit on a five-level scale), the association between lower emotional control and suicidal behavior was substantially stronger in early adulthood (~100% increased hazard per unit) than in late middle age (~30% increased hazard per unit). Conclusions The study adds to previous research by showing that the association between poor emotional control and subsequent suicide risk in men becomes weaker over the life course, while the association between low intelligence and suicide risk seems to be constant. The particularly high suicide risk of young men with poor emotional control may motivate targeted prevention efforts.

Some studies have analyzed the effect of a predictor measured at a later time point (X1), or of the X1-X0 difference, while adjusting for the predictor measured at baseline (X0), on some outcome Y of interest. The present simulation study shows that, if used to analyze the effect of change in X on Y, there is a high risk for this analysis to produce type 1-errors, especially with a strong correlation between true X and Y, when X0 and X1 are not measured with very high reliability, and with a large sample size. These problems are not encountered if analyzing the unadjusted effect of the X1-X0 difference on Y instead, and as this effect exhibits power on par with the adjusted effect it seems as the preferable method when using change between two measurement points as a predictor.

Background\ud \ud The incidence of major depression among adults has been shown to be socially differentiated, and there are reasons to seek explanations for this before adulthood. In this cohort study, we examined whether academic performance in adolescence predicts depression in adulthood, and the extent to which externalizing disorders explain this association.\ud \ud \ud Methods\ud \ud We followed 26,766 Swedish women and men born 1967–1982 from the last year of compulsory school, at age about 16, up to 48 years of age. We investigated the association between grade point average (GPA, standardized by gender) and first diagnosis of depression in national registers of in- or out-patient psychiatric care. We used Cox proportional hazards models, adjusting for lifetime externalizing diagnoses and potential confounders including childhood socioeconomic position and IQ.\ud \ud \ud Results\ud \ud During follow-up, 7.0% of the women and 4.4% of the men were diagnosed with depression. A GPA in the lowest quartile, compared with the highest, was associated with an increased risk in both women (hazard ratio 95% confidence interval 1.7, 1.3–2.1) and men (2.9, 2.2–3.9) in models controlling for potential confounders. Additional control for externalizing disorders attenuated the associations, particularly in women.\ud \ud \ud Conclusions\ud \ud The findings suggest that poor academic performance is associated with depression in young adulthood and that the association is partly explained by externalizing disorders. Our results indicate the importance of early detection and management of externalizing disorders among children and adolescents.

ObjectiveWe aimed to quantify the mediating impact of adult social and behavioural mechanisms in the association between childhood socioeconomic position (SEP) and cardiovascular disease (CVD) mortality by employing a weighting approach to mediation analysis.DesignProspective cohort study.SettingStockholm County, Sweden.Participants19 720 individuals who participated in the Stockholm Public Health Cohort survey in 2002 and were older than 40 years.Primary and secondary outcome measuresThe primary outcome was CVD mortality. Non-CVD mortality was additionally analysed for comparison.MethodsStudy subjects were followed in routine registers from 2002 to 2011 for mortality. Data on father’s SEP and adult social and behavioural factors came from questionnaire survey. The inverse odds weighting method was used to estimate the total effect, the natural direct effect and the natural indirect effect (NIE) in Poisson regression models. All results were adjusted for gender, age, country of birth and marital status. Multiple imputation was used to handle missing data.ResultsThe total effect of manual versus non-manual father’s SEP on CVD mortality was estimated as an incidence rate ratio (IRR) of 1.24 (95% CI 1.09 to 1.41). When the social and behavioural factors were accounted for, the IRR for the NIE was 1.09 (95% CI 1.04 to 1.14), suggesting a mediation of 44% of the total effect. As for non-CVD mortality, father’s manual SEP was associated with 1.15 fold excess risk (IRR: 1.15; 95% CI 1.04 to 1.27) of which the effect represented by the whole set of mediators was 1.06 (95% CI 1.01 to 1.10).ConclusionAdult social and behavioural factors had a considerable mediating effect on the early life social origin of mortality from CVDs and other causes. Future research employing causal mediation analysis may nevertheless have to consider additional factors for a fuller understanding of the mechanisms.

Background The developmental origins of ischemic heart disease (IHD) have been widely documented but little is known about their persistence across more than one generation. This study aimed to investigate whether the effects of early life disadvantages on adult IHD have changed between generations and are mediated by adult socioeconomic circumstances, and further explore the transgenerational effects of grandparental and parental exposures to disadvantaged circumstances on adult offspring's IHD. Methods We used register-based data from the Uppsala Multigenerational Study, Sweden. The study populations were the parents born 1915–1929 and their offspring born 1932–1972 with available obstetric data. The offspring were further linked to grandparents who had their socioeconomic and demographic data recorded. The outcome was incident IHD assessed at ages 32–75 during a follow-up from January 1, 1964 till December 31, 2008. The exposures included birthweight standardized-for-gestational age, ponderal index, gestational length, and parental socioeconomic position (SEP). Education and income were analyzed as mediators. Potential transgenerational associations were explored by linking offspring IHD to parents' standardized birthweight and gestational length, grandparental SEP, and to grandmothers’ age, parity, and marital status at parental birth. All associations were examined in Cox proportional hazard regression models. Results Lower standardized birthweight and lower parental SEP were found to be associated with higher IHD rates in both generations, with no evidence of effect modification by generation. Education and income did not mediate the association between standardized birthweight and IHD. Disadvantaged grandparental SEP, younger and older childbearing ages of grandmothers, and paternal preterm birth affected offspring's IHD independent of parental education, income, or IHD history. Conclusions The findings point to similar magnitudes of IHD inequalities by early life disadvantages across two historical periods and the existence of transgenerational effects on IHD. Epigenetic dysregulation involving the germline is a plausible candidate mechanism underlying the transgenerational associations that warrant further research.

Only a few previously published studies have investigated the co-occurrence and clustering of health-risk behaviors in people with different socio-economic trajectories from childhood to adulthood. This study was based on data collected through the Stockholm County Council's public health surveys. We selected the 24,241 participants aged 30 to 65years, who responded to a postal questionnaire in 2010. Information on parents' and participants' educational levels was used for classification of four socio-economic trajectories, from childhood to adulthood: the 'stable high', the 'upwardly mobile', the 'downwardly mobile', and the 'stable low'. Information on daily smoking, risky drinking, physical inactivity, and poor diet was used for assessment of health-risk behaviors: their prevalence, co-occurrence, and clustering. We found all health-risk behaviors to be more prevalent among women and men with a downwardly mobile or stable low socio-economic trajectory. Accordingly, having three or four co-occurring health-risk behaviors were much more likely (up to 4 times, in terms of odds ratios) in these groups as compared to the women and men with an upwardly mobile or a stable high socio-economic trajectory. However, clustering of the health-risk behaviors was not found to be stronger in those with a downwardly mobile or stable low socio-economic trajectory. Thus, the fact that women and men with a disadvantageous socio-economic career were found to have co-occurring health-risk behaviors more often than people with an advantageous socio-economic career seemed to be generated by differences in prevalence of the health-risk behaviors, not by differences in clustering of the behaviors.

Introduction: The aim of the present study was to investigate the association between exposure to fathers’ alcohol consumption and offspring’s own risk of alcohol-related hospitalization. Methods: Data on circumstances in childhood and adolescence, e.g. fathers’ alcohol consumption at different levels (never, rarely, occasionally, often), parental divorce, as well as offspring’s own risky use of alcohol, smoking and mental health were collected among 49,321 men (sons), born in 1949–51, during conscription for compulsory military training in 1969/70, i.e. at ages 18–20. Data on alcohol-related diagnoses were collected from the Swedish In-patient Care register 1973–2009. Results: The relative risk of alcohol-related diagnoses among sons after the age of 20 increased with increasing level of alcohol consumption in the fathers. Compared with sons whose fathers never drank alcohol, those with fathers who drank alcohol occasionally or often had an increased hazard ratio (HR) of later hospitalization wit...

Objective Many psychosocial factors have been associated with coronary heart disease (CHD), including hostility, anger, and depression. We tested the hypothesis that these factors may have their basis in emotion regulation abilities. Our aim was to determine whether poor emotional control predicted long-term risk of CHD.Methods This Swedish national study includes 46,393 men who were conscripted for military service in 1969 and 1970. The men were aged 18 to 20 years at the time of conscription. Psychologists used a brief semistructured interview to retrospectively assess the conscripts' level of emotional control in childhood and adolescence. The outcome measure was a first fatal or nonfatal event of CHD. We calculated hazard ratios (HRs) and 95% confidence intervals (CIs) for poor and adequate versus good emotional control.Results After 38 years of follow-up (1971-2009), 2456 incident cases of CHD had occurred. Poor emotional control increased the risk of CHD (HR = 1.31, 95% CI = 1.18-1.45), adjusting for childhood socioeconomic position, anxiety, depression, and parental history of CHD. Further adjustment for life-style-related factors, for example, smoking and body mass index, attenuated the HR to 1.08 (95% CI = 0.97-1.21). In stratified analyses, the fully adjusted association between poor emotional control with CHD remained significantly elevated among men with a parental history of CHD (HR = 1.49, 95% CI = 1.11-2.01, p interaction = .037).Conclusions In the overall study population, poor emotional control had no direct effect on CHD beyond life-style-related factors. However, in men with a parental history of CHD, poor emotional control in adolescence remained significantly predictive of long-term CHD risk even when adjusting for life-style-related factors.

Aims To examine associations between cannabis use in adolescence (at age 18) and unemployment and social welfare assistance in adulthood (at age 40) among Swedish men. Design Longitudinal cohort study. Setting and Participants A total of 49 321 Swedish men born in 1949–51, who were conscripted to compulsory military service at 18–20 years of age. Measurements All men answered two detailed questionnaires at conscription and were subject to examinations of physical aptitude psychological functioning and medical status. By follow-up in national databases, information on unemployment and social welfare assistance was obtained. Findings Individuals who used cannabis at high levels in adolescence had increased risk of future unemployment and of receiving social welfare assistance. Adjusted for all confounders (social background, psychological functioning, health behaviours, educational level, psychiatric diagnoses), an increased relative risk (RR) of unemployment remained in the group reporting cannabis use > 50 times [RR = 1.26, 95% confidence interval (CI) = 1.04–1.53] only. For social welfare assistance, RR in the group reporting cannabis use 1–10 times was 1.15 (95% CI = 1.06–1.26), RR for 11–50 times was 1.21 (95% CI = 1.04–1.42) and RR for > 50 times was 1.38 (95% CI = 1.19–1.62). Conclusions Heavy cannabis use among Swedish men in late adolescence appears to be associated with unemployment and being in need of social welfare assistance in adulthood. These associations are not explained fully by other health-related, social or behavioural problems.

Objective: Academic performance in youth, measured by grade point average (GPA), predicts suicide attempt, but the mechanisms are not known. It has been suggested that general intelligence might underlie the association. Methods: We followed 26 315 Swedish girls and boys in population-representative cohorts, up to maximum 46 years of age, for the first suicide attempt in hospital records. Associations between GPA at age 16, IQ measured in school at age 13 and suicide attempt were investigated in Cox regressions and mediation analyses. Results: There was a clear graded association between lower GPA and subsequent suicide attempt. With control for potential confounders, those in the lowest GPA quartile had a near five-fold risk (HR 4.9, 95% CI 3.7-6.7) compared to those in the highest quartile. In a mediation analysis, the association between GPA and suicide attempt was robust, while the association between IQ and suicide attempt was fully mediated by GPA. Conclusions: Poor academic performance in compulsory school, at age 16, was a robust predictor of suicide attempt past young adulthood and seemed to account for the association between lower childhood IQ and suicide attempt.

New data on cause of death suggest the link is mediated by risk factors such as smoking

First, we express our appreciation of the comments on our study by Kawada and by Behrouz and Aachi. We seem to agree on the value of studies on this matter. In both letters, the authors highlight that cannabis use in our study (as well as tobacco and alcohol use) could be measured only in late adolescence and, as a result, little is known about its prevalence later, when cases of stroke occur. Therefore, the authors suspect that our analysis could have missed an association between cannabis use in adulthood and stroke events. This cannot be ruled out, which we touched on in the discussion of our results. However, some prevalence of cannabis use in adulthood is still expected, and we think that in such cases, it was generally preceded by teenage use. With regard to tobacco smoking, >90% of those who were smokers later in life already smoked before …

Background Lower intelligence early in life is associated with increased risks for coronary heart disease (CHD) and mortality. Intelligence level might affect compliance to treatment but its prognostic importance in patients with CHD is unknown. Methods A cohort of 1923 Swedish men with a measure of intelligence from mandatory military conscription in 1969–1970 at age 18–20, who were diagnosed with CHD 1991–2007, were followed to the end of 2008. Primary outcome: recurrent CHD event. Secondary outcome: case fatality from the first event, cardiovascular and all-cause mortality. National registers provided information on CHD events, comorbidity, mortality and socioeconomic factors. Results The fully adjusted HRs for recurrent CHD for medium and low intelligence, compared with high intelligence, were 0.98, (95% CIs 0.83 to 1.16) and 1.09 (0.89 to 1.34), respectively. The risks were increased for cardiovascular and all-cause mortality with lower intelligence, but were attenuated in the fully adjusted models (fully adjusted HRs for cardiovascular mortality 1.92 (0.94 to 3.94) and 1.98 (0.89 to 4.37), respectively; for all-cause mortality 1.63 (1.00 to 2.65) and 1.62 (0.94 to 2.78), respectively). There was no increased risk for case-fatality at the first event (fully adjusted ORs 1.06 (0.73 to 1.55) and 0.97 (0.62 to 1.50), respectively). Conclusions Although we found lower intelligence to be associated with increased mortality in middle-aged men with CHD, there was no evidence for its possible effect on recurrence in CHD.

Background There is a strong belief in the potential of increased physical activity to improve the health of populations. The objective of the present study was to estimate the association between low cardiorespiratory fitness in young adulthood and subsequent health impairment until middle age, measured by disability pension. Methods The study utilised data on cardiorespiratory fitness and a number of covariates (social background, health behaviours and psychological characteristics) from the Swedish Conscription Cohort of 1969/1970 including 49 321 men born in 1949–1951, and data on disability pension from 1971 to 2008 (20–59 years of age) through record linkage with two national insurance databases. Cox proportional-hazards regressions yielded hazard ratios (HR) with 95% confidence intervals (CI). Results Having low-level or mid-level cardiorespiratory fitness in late adolescence was associated with an increased HR of disability pension across the follow-up (HR for low fitness: 1.85, CI 1.71 to 2.00; HR for mid-level fitness: 1.40, CI 1.31 to 1.50). The association was stronger with earlier disability pensions than with later disability pensions, which was also seen after multiple confounding adjustments. At the same time, these adjustments revealed considerable confounding of the association by individual differences in psychological characteristics in particular. Conclusions Lower levels of cardiorespiratory fitness in young adulthood were found to be associated with an increased HR of disability pension throughout the follow-up until 59 years of age, even after adjustment for important confounding factors measured in late adolescence. Increased physical fitness may thus have a lowering effect on the risk of disability pension.

OBJECTIVES: Rates of disability pension are greatly increased among people with low education. This study examines the extent to which associations between education and disability pensions might be explained by differences in working conditions. Information on individuals at age 13 years was used to assess confounding of associations. METHOD: Two nationally representative samples of men and women born in 1948 and 1953 in Sweden (22 889 participants in total) were linked to information from social insurance records on cause (musculoskeletal, psychiatric, and other) and date (from 1986–2008) of disability pension. Education data were obtained from administrative records. Occupation data were used for measurement of physical strain at work and job control. Data on paternal education, ambition to study, and intellectual performance were collected in school. RESULTS: Women were found to have higher rates of disability pension than men, regardless of diagnosis, whereas men had a steeper increase in disability pension by declining educational level. Adjustment of associations for paternal education, ambition to study, and intellectual performance at age 13 had a considerable attenuating effect, also when disability pension with a musculoskeletal diagnosis was the outcome. Despite this, high physical strain at work and low job control both contributed to explain the associations between low education and disability pensions in multivariable models. CONCLUSION: Working conditions seem to partly explain the increased rate of disability pension among men and women with lower education even though this association does reflect considerable selection effects based on factors already present in late childhood.

This study investigated how psychological distress and the proxies for social position combine to influence the risk of both underweight and overweight in South Africans aged 15 years and older. This was a cross-sectional study that included 2254 men and 4170 women participating in the first South African National Health and Nutrition Examination Survey (SANHANES-1). An analysis exploring the associations of social and mental health characteristics with body mass index (BMI) was conducted using binary and multinomial logistic regressions. Results suggested that, overall, women had a higher risk of overweight/obesity compared to men (age-adjusted odds ratio [AOR] 4.65, 95% confidence intervals [CI] 3.94&ndash, 5.50). The gender effect on BMI was smaller in non-African participants (AOR 3.02, 95% CI 2.41&ndash, 3.79, p-value for interaction = 0.004). Being employed and having a higher level of education were associated with higher risks of overweight and obesity and a lower risk of underweight. Being single or without a spouse and poor mental health were found to increase the odds of being underweight, especially in men. To conclude, there are strong social gradients and important gender and ethnic differences in how BMI is distributed in the South African population.

BackgroundIn Sweden, the proportion of the population that remains in paid employment until normal retirement age of 65 years is less than 50% in blue-collar groups, compared to 60%–75% in white-collar occupations. High physical workload has been associated with early exits from the labor market through disability pensions (DP) in many studies. However, identified risk factors for DP from early life may be more prevalent among men in heavy manual occupations than in others. The aim was to investigate the association between high physical work load in middle age and DP before age 59, adjusting for social background, physical ability, psychological characteristics, lifestyle and education measured before labour market entrance.MethodsThe study is based on a Swedish conscription cohort of 49 321 men born 1949–1951. At enlistment 1969/1970 information was collected about cardiorespiratory fitness, social background, psychological characteristics and health behaviours, e.g. smoking. Physical workload was estimated with a job exposure matrix based on questions concerning heavy lifting, strenuous work postures, repetitive work and physically strenuous work from the Swedish Work Environment Surveys 1989–97. Mean values for men of a composite physical exposure variable were grouped into quartiles; high, medium-high, medium-low and low physical workload, and assigned to occupational titles from the census 1990. The study group was followed regarding DP from age 40 to 59.ResultsExposure to high (HR 2.67, CI 95% 2.42–2.95), medium-high (HR 2.43, CI 95% 2.20–2.69) and medium-low (HR 1.31, CI 95% 1.18–1.47) physical workload, compared with low, were associated with DP up to age 59. The increased risks remained, but were clearly attenuated after adjustments for pre-labour market factors, especially psychological characteristics and education.ConclusionThe results are in line with a major effect of high physical work load on disability pension, even though adjustments for pre-labour market factors clearly attenuated the risks.

Background Although unemployment may be a stressful life event, its association with coronary heart disease (CHD) remains unclear. This study examines the association between unemployment and later hospitalisation due to CHD. Methods The study was based on a Swedish military conscription cohort of 18 to 20-year-old men from 1969/1970 (n=49 321) with information provided on health status and health behaviours. Information on unemployment in middle age was obtained from national registers. CHD information was obtained from hospital registers and the cause of death register. Cox proportional hazard analyses were run on the 39 243 individuals who were in paid employment in 1996 and 1997. Results It was found that ≥90 days of unemployment was associated with subsequent CHD during 8 years follow-up (crude HR=1.47, 95% CI 1.23 to 1.75). Controlling for known risk factors for CHD reduced the association but a significant association remained (HR=1.24, 95% CI 1.04 to 1.48); ≥90 days of unemployment was significantly associated with CHD during the first 4 years (HR adjusted for known risk factors=1.31, 95% CI 1.01 to 1.71). Conclusions Unemployment was associated with increased risk of CHD after adjustment for confounders. We interpret the increased risk of CHD associated with unemployment as potentially the somatic result of a process started by stress.

Στόχοι: Να διερευνηθούν οι συσχετισμοί ανάμεσα στη χρήση της κάνναβης στην εφηβεία (σε ηλικία 18 ετών), την ανεργία και τα επιδόματα πρόνοιας στην ενήλικη ζωή (σε ηλικία 40 ετών) σε μια ομάδα ανδρών από τη Σουηδία. Σχεδιασμός: Διαχρονική μελέτη κοόρτης. Χώρος και συμμετέχοντες: Συνολικά 49.321 άνδρες από τη Σουηδία, γεννημένοι μεταξύ 1949–51, οι οποίοι καταταγήκαν υποχρεωτικά στο στρατό σε ηλικία 18-20 ετών. Μετρήσεις: Όλοι οι άνδρες απάντησαν σε δυο εκτενή ερωτηματολόγια κατά τη στράτευσή τους και συμμετείχαν σε εξετάσεις σωματικών ικανοτήτων, ψυχολογικής λειτουργικότητας και ιατρικής κατάστασης. Στοιχεία σχετικά με την ανεργία και το επίδομα ανεργίας συγκεντρώθηκαν μέσω follow-up από εθνικές βάσεις δεδομένων. Ευρήματα: Τα άτομα που έκαναν χρήση κάνναβης σε υψηλά επίπεδα κατά τη διάρκεια της εφηβείας βρίσκονταν σε αυξημένο κίνδυνο για ανεργία και να χρειάζονται επίδομα κοινωνικής πρόνοιας. Μετά την προσαρμογή για όλους τους παράγοντες σύγχυσης (κοινωνικό υπόβαθρο, ψυχολογική λειτουργικότητα, εκπαιδευτικό επίπεδο, ψυχιατρική διάγνωση), παρέμεινε αυξημένος ο δείκτης σχετικού κινδύνου (RR) για ανεργία στην ομάδα που ανέφερε χρήση κάνναβης >50 φορές [RR = 1.26, 95% διάστημα εμπιστοσύνης (CI) = 1.04–1.53] μόνο. Όσον αφορά το επίδομα κοινωνικής πρόνοιας, ο RR ανεργίας στην ομάδα που ανέφερε χρήση κάνναβης 1–10 φορές ήταν 1.15 (95% CI = 1.06–1.26), RR για 11–50 φορές ήταν 1.21 (95% CI = 1.04–1.42) και RR για > 50 φορές ήταν 1.38 (95% CI = 1.19–1.62). Συμπεράσματα: Η σοβαρή χρήση κάνναβης από άνδρες στα τέλη της εφηβείας στη Σουηδία φάνηκε να σχετίζεται με ανεργία και την ανάγκη για βοήθεια από την κοινωνική πρόνοια στην ενήλικη ζωή. Αυτοί οι συσχετισμοί δεν εξηγούνται πλήρως από άλλα προβλήματα: υγείας, κοινωνικά ή συμπεριφοράς. Λέξεις κλειδιά: Κάνναβη, μελέτη κοόρτης, εκπαίδευση, διαχρονική, βοήθεια κοινωνικής πρόνοιας, ανεργία

The question whether a person's attained socioeconomic position is mainly due to hers/his intelligence, socioeconomic background, or level of education, has sparked some controversy. In the present study, the effects of these three variables, as well as emotional capacity, on attained occupational position and on income were analyzed with structural equation modeling in a prospective cohort of Swedish men (N = 48,013), born between 1949 and 1951. Intelligence and level of education were identified to have the strongest total effect on attained occupational position (β = .46 and β = .49, respectively), while the effects of socioeconomic background and emotional capacity were rather weak (β = .19 and β = .11). Except for emotional capacity, the predictors had weaker effects on income than on attained occupational position. A comparison with earlier British studies indicated that in Sweden social position of origin is a less important predictor of a person's attained level of education and socioeconomic or occupational position in midlife.

BackgroundThe association between level of education and disability pension (DP) is well known. Earlier studies have investigated the importance of early life factors and work characteristics but not in combination. The aim of this study was to investigate the association between level of education and DP among Swedish middle-aged working men and to what extent such an association can be explained by factors measured in late adolescence and work characteristics in adulthood.MethodsInformation about IQ, health-related lifestyle factors, psychiatric and musculoskeletal diagnoses was obtained from the 1969 conscription cohort, consisting of 49 321 Swedish men. Data collected when subjects were 18–20 years of age were combined with national register-based information about level of education, job control and physical strain at work in adulthood, and information about DP between 1991 and 2002.ResultsThere was a strong graded association between level of education and DP. Those with the lowest level of education had a four times greater probability of having DP as compared with those with the highest level. In multivariable analyses, factors measured in late adolescence, IQ in particular, attenuated the association more than work-related characteristics in adulthood.ConclusionsThe authors found an association between level of education and DP among Swedish middle-aged working men. A large part of the association was explained by factors measured in late adolescence, IQ in particular, and somewhat less by work characteristics measured in adulthood. Level of education remained as a significant predictor of DP in middle age after full adjustment.