Why does intelligence correlate with life expectancy? This is one component of a web of correlations involving longevity, intelligence, socioeconomic status, and education, among others. While it seems likely that greater intelligence enables better access to and use of medical technology and maintenance of health, a range of evidence suggests that there is a biological component to this relationship, in that more intelligent individuals also tend to be more physically robust. Here, researchers compare data on correlations between genetic variations, measures of intelligence, and measures of mortality risk to estimate the degree to which genetic variation may explain correlations between intelligence and longevity. The result are supportive of some degree of shared genetic causation.
The goal of the research field of cognitive epidemiology is to describe and explain phenotypic associations between cognitive function tested in youth (which largely avoids reverse causation) and later-life health and death. Analyses of long-term follow-up data from large cohorts sourced from the UK, Denmark, Israel, and Sweden show that higher scores on cognitive function tests in youth (childhood, adolescence, or young adulthood) are associated with lower risk of mortality from all causes by mid to late adulthood.
What causes this association? The cognition-longevity relationship was not confounded by childhood socioeconomic position, was present across a range of cognitive ability, and was present in both men and women. Might part of the cognition-longevity association be caused by genetic differences? Large genome-wide association studies (GWASs) have been conducted to examine the molecular genetic etiology of people's differences in cognitive function test scores. There are also GWASs on longevity. These GWAS data enable a comparison between traits; that is, one may compare the loci that attain genome-wide statistical significance in cognition with those that are genome-wide significant in longevity.
To date, we are not aware of any genetic correlation having been reported between cognitive function tested in childhood and longevity. In order to address this lacuna in cognitive epidemiology, we use data from two GWASs to estimate the genetic correlation between cognitive function assessed in childhood and longevity (combined mothers' and fathers' attained age). Using study data on childhood cognitive function (n = 12,441) and on parental longevity (n = 389,166) we found a positive genetic correlation of r = 0.35 between childhood cognitive function and parental longevity. These results add to the weight of evidence that the phenotypic link between childhood cognitive function and longevity is partly accounted for by shared genetic etiology.
Link: https://doi.org/10.61373/gp025l.0098
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