Cognitive and brain development is independently influenced by socioeconomic status and polygenic scores for educational attainment
Authors: Judd Nicholas , Sauce Bruno , Wiedenhoeft John , Tromp Jeshua , Chaarani Bader , Schliep Alexander , van Noort Betteke , Penttilä Jani , Grimmer Yvonne , Insensee Corinna , Becker Andreas , Banaschewski Tobias , Bokde Arun L.W. , Quinlan Erin Burke , Desrivières Sylvane , Flor Herta , Grigis Antoine , Gowland Penny , Heinz Andreas , Ittermann Bernd , Martinot Jean-Luc , Martinot Marie-Laure Paillère , Artiges Eric , Nees Frauke , Orfanos Dimitri Papadopoulos , Paus Tomáš , Poustka Luise , Hohmann Sarah , Millenet Sabina , Fröhner Juliane H. , Smolka Michael N. , Walter Henrik , Whelan Robert , Schumann Gunter , Garavan Hugh , Klingberg Torkel 
Published: December 2019

Genetic factors and socioeconomic (SES) inequalities play a large role in educational attainment, and both have been associated with variations in brain structure and cognition. However, genetics and SES are correlated, and no prior study has assessed their neural associations independently. Here we used polygenic score for educational attainment (EduYears-PGS) as well as SES, in a longitudinal study of 551 adolescents, to tease apart genetic and environmental associations with brain development and cognition. Subjects received a structural MRI scan at ages 14 and 19. At both time-points, they performed three working memory (WM) tasks. SES and EduYears-PGS were correlated (r = 0.27) and had both common and independent associations with brain structure and cognition. Specifically, lower SES was related to less total cortical surface area and lower WM. EduYears-PGS was also related to total cortical surface area, but in addition had a regional association with surface area in the right parietal lobe, a region related to non-verbal cognitive functions, including mathematics, spatial cognition, and WM. SES, but not EduYears-PGS, was related to a change in total cortical surface area from age 14 to 19. This is the first study demonstrating a regional association of EduYears-PGS and the independent prediction of SES on cognitive function and brain development. It suggests that the SES inequalities, in particular parental education, are related to global aspects of cortical development, and exert a persistent influence on brain development during adolescence.

Significance statement

The influence of socioeconomic (SES) inequalities on brain and cognitive development is a hotly debated topic. However, previous studies have not considered that genetic factors overlap with SES. Here we showed, for the first time, that SES and EduYears-PGS (a score from thousands of genetic markers for educational attainment) have independent associations with both cognition and global cortical surface area in adolescents. EduYears-PGS also had a localized association in the brain: the intraparietal sulcus, a region related to non-verbal intelligence. In contrast, SES had global, but not regional, associations, and these persisted throughout adolescence. This suggests that the influence of SES inequalities is widespread – a result that opposes the current paradigm and can help inform policies in education.