The impact of cardiorespiratory fitness and physical workload on disability pension-a cohort study of Swedish men.

OBJECTIVE: Understanding the impact of physical capacity in combination with high physical workload could be beneficial for the prevention of health-related exits from work. Therefore, the aim of this study was to investigate the separate and combined effects of low cardiorespiratory fitness and high physical workload on disability pension (DP) due to any cause, musculoskeletal disorders (MSD), and cardiovascular diseases (CVD). METHODS: A total of 279 353 men born between 1951 and 1961 were followed regarding DP between 2006 and 2020, ages 45-64. Cardiorespiratory fitness was assessed during military conscription, using an ergometer bicycle test. Physical workload was based on a job-exposure matrix (JEM) linked to occupational title in 2005. Cox regression models estimated separate and combined associations with DP. RESULTS: Low cardiorespiratory fitness and high physical workload were associated with increased risk of DP. For all cause DP, the fully adjusted hazard ratio and 95% confidence interval for those with low cardiorespiratory fitness was 1.38 (1.32-1.46) and for those with high physical workload 1.48 (1.39-1.57). For all cause and MSD DP, but not for CVD DP, the combination of low cardiorespiratory fitness and high physical workload resulted in higher risks than when adding the effect of the single exposures. CONCLUSION: Both low cardiorespiratory fitness in youth and later exposure to high physical workload were associated with an increased risk of DP, where workers with the combination of both low cardiorespiratory fitness and a high physical workload had the highest risks (all-cause and MSD DP).

The role of job strain in the relationship between depression and long-term sickness absence: a register-based cohort study.

PURPOSE: Though individuals with depression and those with poor working conditions are more likely to be on long-term sickness absence (LTSA), less is known about how working conditions may modify the associations between depression status and LTSA. This study aims to examine the association between depression and LTSA among Swedish workers with different levels of job strain and its individual components (job demands and job control). METHODS: All Swedish workers 30 - 60 years old (N = 3,065,258) were studied in 2005. At baseline (2005-2010), workers were categorized as: without depression, being prescribed antidepressants, and being in inpatient/outpatient care. Job strain was measured using a Swedish Job Exposure Matrix, and data on LTSA were obtained from 2011 to 2021. The association between depression and LTSA was assessed using Cox proportional-hazards regression stratified by categories of job strain. RESULTS: Compared to workers without depression, workers with depression had higher risk of LTSA across all job strain levels. Depression was associated with the highest hazards of LTSA in active jobs, but a similar population attributable fraction (PAF) was found across categories of job strain, indicating similarities between the different categories. CONCLUSION: There was evidence of a moderating effect of job strain in the relationship between depression and LTSA, but also evidence that this was due to differences in baseline depression prevalence in the different job strain categories. Future research is needed to determine alternative factors which could be relevant for reducing LTSA among those who have already developed depression.

Combined exposure to heavy physical workload and low job control and the risk of disability pension: A cohort study of employed men and women in Sweden.

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.

Job demands and job control and their associations with disability pension-a register-based cohort study of middle-aged and older Swedish workers.

OBJECTIVES: Job demands and control at work and their combination, job strain, have been studied in relation to risk of disability pension (DP) previously. In the present study, based on registry data, we aimed to deepen the knowledge by analyzing major disease groups among the DPs, dose-response shape of the associations, and potential confounding effects of physical workload. METHODS: Approximately 1.8 million workers aged 44 or older and living in Sweden in 2005 were followed up for 16 years, up to a maximum of 65 years of age. We linked mean values of job demands and job control, estimated in a job-exposure matrice (JEM) by gender, to individuals through their occupational titles in 2005. These values were categorized by rank order, and, for the construction of job-strain quadrants, we used a median cut-off. Associations with DP were estimated in Cox proportional-hazards models. RESULTS: In models accounting for covariates including physical workload, low levels of job control were associated with higher risk of DP among both men and women. This association was most clear for DP with a psychiatric diagnosis, although a dose-response shape was found only among the men. High levels of job demands were associated with decreased risk of DP across diagnoses among men, but the same association varied from weak to non-existing among women. The high- and passive job-strain quadrants both showed increased risk of DP with a psychiatric diagnosis. CONCLUSION: The results suggest that, at the occupational level, low job control, but not high job demands, contributes to an increased incidence of DP, particularly regarding DP with a psychiatric diagnosis.

Job control, job demands and job strain and suicidal behaviour among three million workers in Sweden.

OBJECTIVE: To 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. METHODS: Job 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. RESULTS: Low 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. CONCLUSIONS: Low 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.

Depression among teachers: a Swedish register-based study.

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.

Long-term sick leave for back pain, exposure to physical workload and psychosocial factors at work, and risk of disability and early-age retirement among aged Swedish workers.

PURPOSE: 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. METHODS: 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. RESULTS: 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. CONCLUSION: 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.

Educational qualification differences and early labor market exit among men: the contribution of labor market marginalization measured across the working life.

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.

Psychosocial workplace factors and alcohol-related morbidity: a prospective study of 3 million Swedish workers.

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.

Psychosocial working conditions and the risk of diagnosed depression: a Swedish register-based study.

BACKGROUND: High 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. METHODS: Control, 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. RESULTS: Lower 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. CONCLUSION: High 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.

Disability pensions related to heavy physical workload: a cohort study of middle-aged and older workers in Sweden.

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.

How intelligence and emotional control are related to suicidal behavior across the life course - A register-based study with 38-year follow-up.

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.

Academic performance, externalizing disorders and depression: 26,000 adolescents followed into adulthood.

BACKGROUND: 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. METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Fathers' Alcohol Consumption and Long-Term Risk for Mortality in Offspring.

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.

Cannabis, Tobacco, Alcohol Use, and the Risk of Early Stroke: A Population-Based Cohort Study of 45 000 Swedish Men.

BACKGROUND AND PURPOSE: Current knowledge on cannabis use in relation to stroke is based almost exclusively on clinical reports. By using a population-based cohort, we aimed to find out whether there was an association between cannabis use and early-onset stroke, when accounting for the use of tobacco and alcohol. METHODS: The cohort comprises 49 321 Swedish men, born between 1949 and 1951, who were conscripted into compulsory military service between the ages of 18 and 20. All men answered 2 detailed questionnaires at conscription and were subject to examinations of physical aptitude, psychological functioning, and medical status. Information on stroke events up to ≈60 years of age was obtained from national databases; this includes strokes experienced before 45 years of age. RESULTS: No associations between cannabis use in young adulthood and strokes experienced ≤45 years of age or beyond were found in multivariable models: cannabis use >50 times, hazard ratios=0.93 (95% confidence interval [CI], 0.34-2.57) and 0.95 (95% CI, 0.59-1.53). Although an almost doubled risk of ischemic stroke was observed in those with cannabis use >50 times, this risk was attenuated when adjusted for tobacco usage: hazards ratio=1.47 (95% CI, 0.83-2.56). Smoking ≥20 cigarettes per day was clearly associated both with strokes before 45 years of age, hazards ratio=5.04 (95% CI, 2.80-9.06), and with strokes throughout the follow-up, hazards ratio=2.15 (95% CI, 1.61-2.88). CONCLUSIONS: We found no evident association between cannabis use in young adulthood and stroke, including strokes before 45 years of age. Tobacco smoking, however, showed a clear, dose-response shaped association with stroke.

Risk of Coronary Heart Disease in Men With Poor Emotional Control: A Prospective Study.

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.

Prevalence, co-occurrence, and clustering of health-risk behaviors among people with different socio-economic trajectories: A population-based study.

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.

Long-term physical workload in middle age and disability pension in men and women: a follow-up study of Swedish cohorts.

PURPOSE: The study investigates the association between level of long-term physical workload in middle age and disability pension (DP) before 61 years of age with adjustments made for early life factors, level of education, and psychosocial working conditions. Associations with DP overall, DP due to musculoskeletal disorders and DP due to psychiatric disorders were examined. METHODS: The study is based on cohorts of 21,809 Swedish men and women born in 1948 and 1953, with data on physical workload estimated with a job exposure matrix based on occupational titles in 1985 and 1990 and follow-up data on diagnosis-specific DP in the years 1991-2009. Data on paternal education and intelligence were collected in primary school. Data on level of education were taken from administrative records. Data on psychosocial working conditions were estimated with a job exposure matrix based on occupational titles in 1990. RESULTS: Long-term exposure to high physical workload measured 5 years apart at around age 40 was strongly associated with DP due to musculoskeletal disorders up to the age of 61 among both men (HR 5.44, 95 % CI 3.35-8.84) and women (HR 3.82, CI 95 % 2.88-5.08). For women, the association between high physical load and overall DP was also significantly increased (HR 2.33, CI 95 % 1.92-2.82). The increased risks remained but were clearly attenuated after adjustments for fathers' education, IQ in childhood, achieved education and level of control at work. CONCLUSIONS: Exposure to high physical workload is associated with long-term risk of DP due to musculoskeletal disorders, even though adjustments for early life factors, level of education and psychosocial working conditions clearly attenuated the risks.

Unemployment and coronary heart disease among middle-aged men in Sweden: 39 243 men followed for 8 years.

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.

A formal model accounting for measurement reliability shows attenuated effect of higher education on intelligence in longitudinal data.

The effect of higher education on intelligence has been examined using longitudinal data. Typically, these studies reveal a positive effect, approximately 1 IQ point per year of higher education, particularly when pre-education intelligence is considered as a covariate in the analyses. However, such covariate adjustment is known to yield positively biased results if the covariate has measurement errors and is correlated with the predictor. Simultaneously, a negative bias may emerge if the intelligence measure after higher education has non-classical measurement errors as in data from the 1970 British Cohort Study that were used in a previous study of the effect of higher education. In response, we have devised an estimation method that used iterated simulations to account for both classical measurement errors in the covariate and non-classical errors in the dependent variable. Upon applying this method in a reanalysis of the data from the 1970 British Cohort Study, we find that the estimated effect of higher education diminishes to 0.4 IQ points per year. Additionally, our findings suggest that the impact of higher education is somewhat more pronounced in the initial 2 years of higher education, aligning with the notion of diminishing marginal cognitive benefits.