A big mess of correlations exists between social status, wealth, intelligence, education, stress, life expectancy, and a range of aspects of our biology linked to variations in longevity, such as telomere length, epigenetic patterns of DNA methylation, and so forth. There are many moving parts here and the situation is complex enough that I imagine people will still be gathering data and arguing over interpretations long after the research community has created means of rejuvenation, ways to extend healthy life by far greater amounts than the present natural variations in human life span, that will make all of this irrelevant:
Epigenetic programming and epigenetic mechanisms driven by environmental factors are thought to play an important role in human health and ageing. Global DNA methylation has been postulated as an epigenetic marker for epidemiological studies as it is reflective of changes in gene expression linked to disease. Insufficient maternal care or diet can be reflected in the methylation status of their offspring. Indeed, an inherited sensitivity to stress, influenced by the mood of the mother during pregnancy, has also been reported. These observations suggest that there may be an adaptive mechanism which allows for epigenetic plasticity in response to environmental changes. A broad range of environmental factors may therefore impact on global DNA methylation status and consequently health. This is important to the understanding of the impact of socio-economic drivers of ill health, which may be predominant in communities where there is also a higher prevalence of classical risk factors for disease.
The aim of this study was to investigate the relationship between socio-economic and lifestyle factors and epigenetic status, as measured by global DNA methylation content, in the pSoBid cohort, which is characterized by an extreme socio-economic and health gradient. Global DNA hypomethylation was observed in the most socio-economically deprived subjects. Job status demonstrated a similar relationship, with manual workers having 24% lower DNA methylation content than non-manual. Additionally, associations were found between global DNA methylation content and biomarkers of cardiovascular disease (CVD) and inflammation, including fibrinogen and interleukin-6 (IL-6), after adjustment for socio-economic factors.