Suicide attempt predicted by academic performance and childhood IQ: a cohort study of 26 000 children

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.

The association between masculinity rank and mortality patterns: a prospective study based on the Swedish 1969 conscript cohort

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 five-grade 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 all-cause 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.

Body mass index in late adolescence and its association with coronary heart disease and stroke in middle age among Swedish men

BACKGROUND AND OBJECTIVES

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.

METHODS

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.

RESULTS

A graded increase of CHD was seen in over six levels of BMI (BMI<18.5, 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; BMI > or =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.

CONCLUSION

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.