Abstract
Cognitive ability has been shown to be inversely associated with several health outcomes, both somatic and psychiatric. The findings regarding the association between cognitive function and alcohol-related outcomes have however not been consistent. Furthermore, there has been a lack of knowledge regarding possible differences between genders and what mechanisms there would be that could explain the association. Also, information regarding school performance and alcohol-related outcomes has been needed. The overarching aim of this thesis was to further investigate the association between cognitive function, alcohol use and alcohol-related harm.
Three different data bases were used in this thesis, The Swedish Conscript Cohort consisting of 49 321 Swedish males, the Evaluation Through Follow-up data base with a total of 21 809 Swedish men and women and School Register data with a total of 213 395 Swedish men and women.
In study I, using the Swedish Conscript cohort, we investigated the association between IQ-test results from late adolescence and alcohol-related hospital admission and death. An inverse, grade association was found for both outcomes. This was a longitudinal, cohort study.
In study II, using the Swedish Conscript cohort, the association between IQ-test results in late adolescence and alcohol consumption, measured both as total alcohol intake and pattern of drinking. Lower IQ-test results were found to be associated with a higher alcohol consumption, regarding both outcomes.
In study III, using the Evaluation Through Follow-up data base, we found an inverse graded association between IQ-test results measured in childhood and alcohol-related hospital admission and death. There seemed to be no interaction for gender in the association, and socio-economic position as adult was assessed to at least partly mediate in the found association, for both outcomes.
In study IV, using School register data, we found a graded, inverse association between grade point average from 9th grade and alcohol-related admission to hospital, for both men and women. IQ-test result did not seem to be a confounder in the association.
In conclusion, we found that IQ-test results and school grades were inversely associated with alcohol use and alcohol-related harm. The results were similar for men and women, where investigated and socio-economic position as adult, was assessed a possible mediator in the association between intelligence and alcohol-related harm.
