Epigenetic Mechanisms in Childhood Obesity.

Epigenetic mechanisms, including DNA methylation, histone modification, and activity of noncoding RNAs (nc RNAs), affect the regulation of gene expression. These mechanisms are regulated by numerous environmental factors and are critical at specific windows of biological development, when organs and systems plasticity is increased. Evidence suggests that exposure to factors influencing these mechanisms may have an effect on health, including the risk for obesity at early stages of life. This study analyzed published evidence on the association between epigenetic mechanisms and childhood obesity. We searched for studies using untargeted detection methods followed by validation of associations between epigenetic mechanisms and obesity in children. Fifteen studies were found: two meta-analyses on DNA methylation, seven original studies on DNA methylation, one systematic review on microRNAs, and five studies on nc RNA. No studies on histone modifications were identified. Most studies were conducted in blood cells or blood-derived fluids. DNA methylation in different tissues was associated with childhood and adolescent obesity or related phenotypes, although comparison across studies is difficult due to technical differences. Nc RNA differed between children with and without obesity. Research on the role of factors regulating epigenetic mechanisms associated with childhood obesity is highly needed.