Social origin, schooling and individual change in intelligence during childhood influence long-term mortality: a 68-year follow-up study

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 educational gradient in coronary heart disease: the association with cognition in a cohort of 57,279 male conscripts

BACKGROUND

Independently of cardiovascular disease (CVD) risk factors, cognitive ability may account for some of the excess risk of coronary heart disease (CHD) associated with lower education. We aimed to assess how late adolescence cognitive ability and midlife CVD risk factors are associated with the educational gradient in CHD in Norway.

METHODS

In a cohort of 57 279 men born during 1949-1959, health survey information was linked to military conscription records of cognitive ability, to national educational data, to hospitalisation records from the Cardiovascular Disease in Norway (CVDNOR) project and to the Norwegian Cause of Death Registry.

RESULTS

Age and period adjusted HR for incident CHD events was 3.62 (95% CI 2.50 to 5.24) for basic relative to tertiary education, and was attenuated after adjustment; to 2.86 (1.87 to 4.38) for cognitive ability, to 1.90 (1.30 to 2.78) for CVD risk factors, and to 1.84 (1.20 to 2.83) when adjusting for both. Age and period adjusted absolute rate difference was 51 (33 to 70) incident CHD events per 100,000 person years between basic and tertiary educated, and was attenuated after adjustment; to 42 (22 to 61) for cognitive ability, to 25 (7 to 42) for CVD risk factors, and to 24 (5 to 43) when adjusting for both.

CONCLUSIONS

Late adolescence cognitive ability attenuated the educational gradient in incident CHD events. CVD risk factors further attenuated the gradient, and to the same extent regardless of whether cognitive ability was included or not. Cognitive ability might be linked to the educational gradient through CVD risk factors.

Improved planning abilities in binge eating

Objective

The role of planning in binge eating episodes is unknown. We investigated the characteristics of planning associated with food cues in binging patients. We studied planning based on backward reasoning, reasoning that determines a sequence of actions back to front from the final outcome.

Method

A cross-sectional study was conducted with 20 healthy participants, 20 bulimia nervosa (BN), 22 restrictive (ANR) and 23 binging anorexia nervosa (ANB), without any concomitant impulsive disorder. In neutral/relaxing, binge food and stressful conditions, backward reasoning was assessed with the Race game, promotion of delayed large rewards with an intertemporal discounting task, attention with the Simon task, and repeating a dominant behavior with the Go/No-go task.

Results

BN and to a lower extent ANB patients succeeded more at the Race game in food than in neutral condition. This difference discriminated binging from non-binging participants. Backward reasoning in the food condition was associated with lower approach behavior toward food in BN patients, and higher food avoidance in ANB patients. Enhanced backward reasoning in the food condition related to preferences for delayed large rewards in BN patients. In BN and ANB patients the enhanced success rate at the Race game in the food condition was associated with higher attention paid to binge food.

Conclusion

These findings introduce a novel process underlying binges: planning based on backward reasoning is associated with binges. It likely aims to reduce craving for binge foods and extend binge refractory period in BN patients, and avoid binging in ANB patients. Shifts between these goals might explain shifts between eating disorder subtypes.