More Evidence for a Common Genetic Contribution to Both Education and Longevity

A web of correlations exist in human data between social status, wealth, education, intelligence, and natural variations in longevity. One can propose possible mechanisms, such as better access to medical technology and greater willingness to use it well, and better care of the health basics such as diet, exercise, and weight. Intriguingly there are some signs that genetics may have some influence over this picture, with studies suggesting that more intelligent individuals tend to also be more robust and longer-lived. This remains far less convincing than the hypothesis that more intelligent people tend to take better care of their long-term health, however, going simply by weight of evidence. Still, here is another paper that runs along these lines:

Individual differences in educational attainment have been linked to variation in life chances and longevity: those with more education tend to be healthier, richer in adulthood, more upwardly socially mobile, and longer-lived. Because education influences - and is influenced by - various personal characteristics and social factors, it has been difficult to disentangle the precise reasons for its prediction of key life outcomes. Despite it being widely used in studies as a social-environmental variable, differences in education are under substantial genetic influence, with heritability frequently estimated at 60% and above in family studies, and 20-30% in molecular genetic studies. Some specific education-associated genetic variants have also been uncovered in genome-wide association studies (GWAS). The present study uses previously-discovered genetic correlates of education to predict variation in arguably the most important life outcome of all: longevity.

The association of educational outcomes-measured either by attained qualifications or by duration of full-time education - with longevity is well established in the scientific literature. The high value placed upon educational qualifications in society and in the labor market forms one possible explanation for this link: the higher-level occupations and socioeconomic positions afforded by better education allow greater access to health-improving resources and surroundings. However, education also acts as a signal for personal characteristics with which it is phenotypically correlated, such as general cognitive ability, motivation, and health, in addition to aspects of a person's socio-economic background. Thus, according to two nonmutually exclusive views, educational attainment might cause improvements in longevity via social mechanisms, or might itself be caused by preexisting - partly heritable - factors that also increase longevity.

Some evidence for the latter view - that some of the variance in educational attainment and longevity is caused by preexisting factors - comes from the pervasive genetic correlations of education with many other longevity-linked traits, indicating that these traits are substantially associated with the same genetic variants. For example, one study used linkage-disequilibrium (LD) regression analysis to show that educational attainment was significantly genetically correlated with lifespan-limiting conditions like cardiovascular disease and stroke. In addition, educational attainment is strongly genetically correlated with general cognitive ability, itself a well-replicated phenotypic and genetic correlate of longevity.

In this study, we tested whether the genetic variants associated with educational attainment are associated with longevity. We thus assessed the extent to which the genetic contributions to educational outcomes, which are preexisting and nonsocial, are related to a key health outcome. To do so, we used the established technique of testing for associations between genotyped subjects and their phenotyped relatives (in this case, the lifespan of parents). Here, we used summary data from an independent GWAS of educational attainment to create polygenic profile scores. These scores quantify the extent to which each participant carried the genetic variants known to be associated with higher educational attainment (in the GWAS, education was measured as the number of years of education). We then linked these polygenic profile scores to data on the participants' parents' age at death. Our hypothesis was that offspring with polygenic profiles for higher educational attainment would have longer-living parents.

This study found that offspring polygenic profiles for education were robustly associated with parental longevity: those with more genetic variants related to better educational qualifications had longer-living parents. We tested the study's principal hypothesis across three large cohorts, totaling over 130,000 participants. The associations were of broadly similar effect size in all three cohorts. Parents with offspring in the upper third of the polygenic score distribution lived an average of 0.55 years longer than those in the lower third. The results - which were comparable to the effect sizes from other known predictors of mortality, such as cardiovascular disease and smoking, and which were bolstered by the finding of a moderate-sized genetic correlation between the two variables - suggest the hypothesis that the ultimate reason education predicts mortality is, in part, because of an underlying, quantifiable, genetic propensity.


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