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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.

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.

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.

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.

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.

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.

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.

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.

Background: Being male constitutes a risk factor for early death, and this may be connected to concepts of masculinity. The objective of the present study was to investigate the association between masculinity rank during late adolescence and mortality patterns in a cohort of 49 321 Swedish men tested for compulsory military training in 1969. Methods: The measure of masculinity consisted of a fivegrade ranking from the conscription information that comprised leisure interests and occupational preferences. Information on all-cause mortality, alcohol-related mortality, suicide, mortality from other violent causes and mortality from cardiovascular disease was collected from national registers for 1970‐2003. The analyses were performed using Cox proportional hazard models with hazard ratios as estimates of relative risk. Results: For all-cause mortality, the crude relative risks versus ordinary masculinity were: lowest masculinity 1.98 (95% CI 1.71 to 2.31), low masculinity 1.38 (95% CI 1.24 to 1.53), high masculinity 0.90 (95% CI 0.81 to 1.01) and highest masculinity 0.78 (95% CI 0.62 to 0.97). After adjustments for childhood class, smoking, alcohol drinking, blood pressure, short stature, psychiatric disorder, low intelligence and contact with police or childcare authorities, conscripts who were ranked lowest on masculinity had a remaining increased relative risk of allcause mortality (1.49; 95% CI 1.28 to 1.75) and suicide (1. 79; 95% CI 1.31 to 2.43). For mortality from violent causes other than suicide, no statistically significant associations were demonstrated. Conclusions: Earlier research has proposed that masculinity may hold both positive and negative aspects regarding lifetime health. The major conclusion here is that being ranked less masculine is associated with higher mortality.

The association between blood pressure measured in late adolescence and early incidence of coronary heart disease and stroke was investigated in Swedish men. We used measures of systolic blood pressure, diastolic blood pressure, mean arterial pressure, and pulse pressure.Information on blood pressure at age 18-20 was obtained from a cohort of 49,321 men born in 1949-1951 examined at conscription in 1969/1970. Information on coronary heart disease, acute myocardial infarction, and stroke during 1971-2004 was obtained from national hospital discharge and cause of death registers. Associations between blood pressure and outcomes were estimated with Cox regression as hazard ratios per standard deviation in blood pressure increase in mmHg.Blood pressure at age 18-20 was found to be associated with coronary heart disease and stroke before 55 years of age. Adjustment for childhood socio-economic position and adolescent smoking, body mass index, and cognitive ability attenuated the associations. Systolic blood pressure was associated with coronary heart disease [hazard ratio (95% confidence interval) 1.09 (1.04, 1.15)] and acute myocardial infarction [1.09 (1.02, 1.17)]. Diastolic blood pressure was associated with coronary heart disease [1.06 (1.00, 1.11)], acute myocardial infarction [1.08 (1.01, 1.15)], and stroke [1.12 (1.04, 1.21)]. Blood pressure measured as mean arterial pressure was significantly associated with coronary heart disease and almost significantly associated with stroke. Pulse pressure had the weakest associations with all outcomes.Measures of blood pressure in late adolescence were found to be associated with early incidence of coronary heart disease and stroke. Prediction of outcomes differed between measures.

ObjectiveTo investigate the association between intelligence and disability pension due to mental, musculoskeletal, cardiovascular, and substance-use disorders among men and women, and to assess the role of childhood social factors and adulthood work characteristics.MethodsTwo random samples of men and women born 1948 and 1953 (n = 10 563 and 9 434), and tested for general intelligence at age 13, were followed in registers for disability pension until 2009. Physical and psychological strains in adulthood were assessed using job exposure matrices. Associations were examined using Cox proportional hazard regression models, with increases in rates reported as hazard ratios (HRs) with 95% confidence intervals (95%CI) per decrease in stanine intelligence.ResultsIn both men and women increased risks were found for disability pension due to all causes, musculoskeletal disorder, mental disorder other than substance use, and cardiovascular disease as intelligence decreased. Increased risk was also found for substance use disorder in men. In multivariate models, HRs were attenuated after controlling for pre-school plans in adolescence, and low job control and high physical strain in adulthood. In the fully adjusted model, increased HRs remained for all causes (male HR 1.11, 95%CI 1.07-1.15, female HR 1.06, 95%CI 1.02-1.09) and musculoskeletal disorder (male HR 1.16, 95%CI 1.09-1.24, female HR 1.08, 95%CI 1.03-1.14) during 1986 to 2009.ConclusionRelatively low childhood intelligence is associated with increased risk of disability pension due to musculoskeletal disorder in both men and women, even after adjustment for risk factors for disability pension measured over the life course.

Body mass index (BMI) in adolescence may be of particular importance as a predictor of future risk of coronary heart disease (CHD). Associations measured either in childhood or in middle age have appeared to be weaker or non-existent. We investigated the association between BMI measured in adolescence and CHD, and also stroke, among middle aged Swedish men and controlled for potential confounders not included in previous studies.Data on BMI, smoking and blood pressure (diastolic and systolic) was collected from 49,321 Swedish males, born during 1949-1951, at conscription for military service in 1969/70. Census data on socioeconomic indicators in childhood and adulthood was linked to the cohort. The men were followed from 1991 through 2004 in national registers with regard to mortality and hospitalization from CHD and stroke.A graded increase of CHD was seen in over six levels of BMI (BMI18.5, hazard ratio (HR)=1.0, BMI=18.5-20.99 (reference category), BMI=21-22.99, HR=1.2; BMI=23-24.99, HR=1.5; BMI=25-29.99, HR=2.5; BMIor =30, HR=4.3). A graded association between BMI and stroke was also found, although weaker. Adjustments for cardiovascular risk factors (smoking, diastolic and systolic blood pressure, and early cardiovascular mortality in parents) attenuated the relative risks to some extent, whereas adjustments for socioeconomic indicators in childhood and adulthood had minor effects.The results strongly suggest that BMI in late adolescence is an important predictor of both CHD and stroke among men before age 55 years, independent of smoking, hypertension and early cardiovascular mortality in parents.

Aims This study aimed at examining a possible association between cannabis use in adolescence and future disability pension (DP). DP can be granted to any person in Sweden aged 16–65 years if working capacity is judged to be permanently reduced due to long-standing illness or injury. Methods Data were obtained from a longitudinal cohort study comprising 49,321 Swedish men born in 1949–1951 who were conscripted to compulsory military service aged 18–20 years. Data on DP was collected from national registers. Results Results showed that individuals who used cannabis in adolescence had considerably higher rates of disability pension throughout the follow-up until 59 years of age. In Cox proportional-hazards regression analyses, adjustment for covariates (social background, mental health, physical fitness, risky alcohol use, tobacco smoking and illicit drug use) attenuated the associations. However, when all covariates where entered simultaneously, about a 30% increased hazard ratio of DP from 40 to 59 years of age still remained in the group reporting cannabis use more than 50 times. Conclusions This study shows that heavy cannabis use in late adolescence was associated with an increased relative risk of labor market exclusion through disability pension.

Low cognitive ability in late adolescence has previously been shown to be associated with disability pension (DP) in young adulthood. However, most DP’s are granted later in working life, and the mechanisms of the association are not fully understood. We aimed to investigate the association between cognitive ability in late adolescence and DP at ages 40-59, and investigate the role of individual and socioeconomic factors. Information on cognitive ability, health status, personality aspects and health behaviours at age 18-20 was obtained from the 1969-70 conscription cohort, comprising 49 321 Swedish men. Data on DP’s 1991-2008 was obtained from the Longitudinal Database of Education, Income and Employment. Information on socioeconomic and work-related factors in childhood and adulthood was obtained from national sociodemographic databases. Hazard ratios for DP during follow-up were estimated by Cox proportional hazards models. We found a graded relationship between cognitive ability in late adolescence and DP in middle age. One step decrease on the nine-point stanine scale of cognitive ability was associated with a crude hazard ratio of 1.26 (95 % CI 1.24-1.27). Socioeconomic and work-related circumstances in adulthood explained much of the association, but factors measured already in late adolescence also showed importance. The findings suggest an accumulation of risks over the life course. Although attenuated, the graded relationship remained after adjusting for all factors.

Background: Poor social circumstances in childhood are associated with increased risk of coronary heart disease (CHD). In previous studies, social circumstances and risk factors in adulthood have been suggested to explain this association. In the present study, we included potential explanatory factors from childhood and adolescence. Methods: We investigated the association between childhood socio-economic position (SEP) and CHD in middle age among 49 321 Swedish males, born during 1949–51, who were conscripted for military service at 18–20 years of age. Register-based data on childhood social circumstances, educational attainment and occupational class in adulthood were used in combination with information on cognitive ability, smoking, body mass index and body height in late adolescence obtained from a compulsory conscription examination. Incidence of CHD from 1991 to 2007 (between 40 and 58 years of age) was followed in national registers. Results: We demonstrated an inverse association between childhood SEP and CHD in middle age: among men with the lowest childhood SEP the crude hazard ratio of CHD was 1.47 (95% CI = 1.30–1.67). Adjustment for crowded housing in childhood, body height, cognitive ability, smoking and BMI in late adolescence attenuated relative risks of CHD considerably. Additional adjustment for educational level had a further, although limited, attenuating effect on associations, but additional adjustment for occupational class had no such effect. Conclusions: Results showed that social, cognitive and behavioural factors evident prior to adulthood may be of greater importance in explaining the association between childhood SEP and CHD later in life than socio-economic indicators in adulthood.

Background Previous studies suggest that the risk of coronary heart disease (CHD) may be related to educational level. In the present study, we looked at factors in childhood and adolescence as potential confounders of the relationship between educational level and risk of CHD. We also examined hypothesized mediation by socioeconomic factors in adulthood. Method The 1969 conscription cohort consisting of 49,321 Swedish men born in 1949 through 1951, who conscripted for military service in 1969/70, provided information on potential confounders. This was linked with register-based information on childhood social circumstances, education level, occupational class, income and job control in adulthood, and follow-up information on CHD during 1991 through 2007. Results The relative risk of CHD increased with lower educational level. Among men with the lowest educational level, the relative risk of CHD was 1.81 (95% confidence interval, 1.60–2.05) compared with the highest educated group of men. Adjustment for childhood socioeconomic circumstances, and cognitive ability and behavior-related factors measured in late adolescence, attenuated the association considerably. Additional adjustment for socioeconomic position, income, and job control in adulthood did not attenuate the association further. Conclusion It may be that educational level and risk of CHD are associated importantly owing to confounding from factors in childhood and adolescence.

An association of higher body mass index (BMI) with lower risk of attempted and completed suicide has been reported. In contrast, increasing BMI has been found to be associated with depression and other risk factors for suicidal behavior. We aimed to investigate this possible paradox in a cohort comprising 49 000 Swedish men. BMI, mental health, lifestyle and socioeconomic measures were recorded at conscription in 1969–70, at ages 18–20. Information on attempted suicide 1973–2008 and completed suicide 1971–2008 was obtained from national records. Hazard ratios (HR) were estimated by Cox proportional hazard models. We found that each standard deviation (SD) increase in BMI was associated with a 12% lower risk of later suicide attempt (HR 0.88, 95% CI 0.83–0.94). Associations were somewhat weaker for completed suicide and did not reach conventional levels of statistical significance (HR 0.93, 95% CI 0.85–1.01). Adjustment for a wide range of possible confounding factors had little effect on the associations. Lower BMI at conscription was also associated with higher prevalence of psychiatric diagnoses, low emotional control and depressed mood. Our results confirm previous findings regarding the association of higher BMI with a reduced risk of suicide, extending them to show similar findings in relation to suicide attempts. The associations were little affected by adjustment for a range of possible confounding factors. However, we found no evidence that high BMI was associated with an increased risk of depression cross-sectionally or longitudinally.