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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.

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.

The possible contributions of psychosocial functioning and intelligence differences to socioeconomic status (SES)-related inequalities in premature death were investigated. None of the previous studies focusing on inequalities in mortality has included measures of both psychosocial functioning and intelligence.The study was based on a cohort of 49 321 men born 1949-1951 from the general community in Sweden. Data on psychosocial functioning and intelligence from military conscription at ∼18 years of age were linked with register data on education, occupational class, and income at 35-39 years of age. Psychosocial functioning was rated by psychologists as a summary measure of differences in level of activity, power of initiative, independence, and emotional stability. Intelligence was measured through a multidimensional test. Causes of death between 40 and 57 years of age were followed in registers.The estimated inequalities in all-cause mortality by education and occupational class were attenuated with 32% (95% confidence interval: 20-45%) and 41% (29-52%) after adjustments for individual psychological differences; both psychosocial functioning and intelligence contributed to account for the inequalities. The inequalities in cardiovascular and injury mortality were attenuated by as much as 51% (24-76%) and 52% (35-68%) after the same adjustments, and the inequalities in alcohol-related mortality were attenuated by up to 33% (8-59%). Less of the inequalities were accounted for when those were measured by level of income, with which intelligence had a weaker correlation. The small SES-related inequalities in cancer mortality were not attenuated by adjustment for intelligence.Differences in psychosocial functioning and intelligence might both contribute to the explanation of observed SES-related inequalities in premature death, but the magnitude of their contributions likely varies with measure of socioeconomic status and cause of death. Both psychosocial functioning and intelligence should be considered in future studies.

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.