Adiposity is an important risk factor for many aging-related conditions such as type 2 diabetes, cardiovascular disease, cancer, injuries, physical function disabilities, and premature mortality. The etiology of adiposity is multifactorial and known to have genetic and environmental determinants, and focus has recently turned to understanding the biological mechanisms by which genetic and environmental factors operate. More specifically, there is increasing interest in exploring biological pathways by which adverse early-life exposures affect adiposity later in life. Epigenetics, or the modification of gene expression in organisms due to external environmental stimuli, may play an important role in mediating this relationship.
[Photo: Dr. Eric Loucks]
The purpose of this study, led by Dr. Eric Loucks, assistant professor of epidemiology, was to evaluate whether associations of childhood socioeconomic disadvantage and adult body mass index are mediated by DNA methylation, an epigenetic mechanism. Participants for this study were 141 men and women from the New England Family Study, who were prospectively followed prenatally though a mean age of 47 years.
The researchers found that, of CpG sites significant at the 25 percent false discovery rate level in epigenome wide methylation body mass index analyses, 91 sites in men and 71 sites in women were additionally significant for SES-methylation associations in adipose tissue. Many involved genes biologically relevant for development of obesity, including fatty acid synthase, transmembrane protein 88, signal transducer and activator of transcription 3, and neuritin 1. There was no evidence of epigenetic mediation in peripheral blood leukocytes.
The results of this study suggest that DNA methylation at specific genes, an epigenetic mechanism, may mediate the associations between childhood socioeconomic disadvantage and mid-life body mass index. Findings motivate continued efforts to study if and how childhood socioeconomic disadvantage is biologically embedded at the level of the epigenome. Furthermore, plausible biological markers could one day serve as early biological indicators of socioeconomic intervention effectiveness or as therapeutic targets.
This study was published in Psychosomatic Medicine.