The biological effect of low education is not as direct as that of smoking

Many social scientists believe that a variety of social environmental factors have an effect on the epigenome, which is the set of chemical changes to the DNA and its related proteins. However, so far there has been little evidence to date in humans about that. According to a group of researchers, social environmental conditions have a smaller epigenetic effect compared to factors with a more direct biological impact – such as smoking, alcohol consumption or body mass index.

This is the main outcome of a study published on Molecular Psychiatry by scientists from the Lifepath project, a research consortium funded by the European Commission to study how differences in socio-economic conditions may affect our biology and, thus, our health.

Educational attainment is arguably among the most important life-shaping experiences for individuals in modern societies and, therefore, a useful test case for whether and to what extent biologically distal environmental factors may affect the epigenome.

Lifepath researchers performed an analysis on about 11 thousand individuals across 27 cohort studies, from Europe, US and Australia. They specifically investigated the relationship between educational attainment and one of the most widely studied epigenetic mark, the CpG DNA methylation. Previous studies have found associations between DNA methylation and, for example, smoking, body-mass index, traumatic stress, alcohol consumption and cancer.

One plausible hypothesis is that environmental influences on the epigenome, even those due to everyday, social environmental factors, are pervasive and profound. Educational attainment is a major life experience that occurs over many years. Thus, Lifepath researchers were expecting to find large associations between this social trait and DNA methylation. However, they found out that educational attainment exhibited weaker associations with methylation compared to factors like smoking or alcohol consumption. This may be due to the fact that these factors have a more direct effect on our biology. Also, they could be the instruments through which poor educational conditions might affect our body and our health.

Lifepath study provides one of the first large-scale investigations in humans of epigenetic changes linked to a biologically distal environmental factor like educational level. It is now necessary to confirm these results with larger studies, and to extend this kind of analysis to relevant social factors other than educational attainment, to see if Lifepath results can be generalised to other biologically distal environmental factors.

Publication date: 
Wednesday, November 8, 2017