The role of education and cognitive skills in understanding mortality inequalities

The overall aim of this thesis is to improve our understanding of the association between cognitive skills and mortality by epidemiological analyses of their relationship. Related factors, especially own and father’s education, are also analysed. This field or research is approached in three observational studies and one quasiexperimental study.

Previous research suggests that higher cognitive skills as measured by IQ tests in childhood predict lower risk of premature mortality. A related field of research demonstrates how schooling is associated to increases of IQ. Longer schooling in itself is also known to be related to longer life. Still how these associations should be understood is not clear.

In this thesis it is argued that education is indeed casually related to lower mortality - and that this can be partly explained by the effect of schooling on cognitive skills. It is also argued that the association between cognitive skills and health cannot be reduced to people being ‘clever because they are healthy’ or to the position of one individual relative to other individuals. Since cognitive skills relate to every individual in a population and since they can be improved, new ways of thinking about promotion of population health are implied.

Improvements of both cognitive skills and average life expectancy in a population could in principle be achieved at the same time as differences between individuals in a population are reduced.

List of scientific papers

I. Lager A, Bremberg S, Vågerö D. The association of early IQ and education with mortality: 65 year longitudinal study in Malmö, Sweden. BMJ. 2009;339(b5282).
https://doi.org/10.1136/bmj.b5282

II. Lager A, Vågerö D, Bremberg S. The effects of own childhood intelligence, own education and partner’s education on mortality between age 54 and 78: A prospective study. [Submitted]

III. Lager A, Torssander J. The causal effect of education on mortality: 58-year follow-up of a quasi-experiment on 1.2 million Swedes. [Submitted]

IV. Lager A, Modin B, De Stavola B, Vågerö D. Social origin, schooling and individual change in intelligence during childhood influence long-term mortality: a 68-year follow-up study. Int J Epidemiol. 2011:1-7.
https://doi.org/10.1093/ije/dyr139