High BMI leads to epigenetic changes at nearly 200 loci of the genome – with effects on gene expression. This is the result of a large-scale international study coordinated by Helmholtz Zentrum München, a partner in the German Center for Diabetes Research.
An international research team led by Dr. Christian Gieger and Dr. Harald Grallert (as well as Jaspal Kooner and John Chambers of Imperial College London) examined possible correlations between body mass index (BMI) and epigenetic changes.

The scientists examined the blood samples of over 10,000 women and men from Europe. A large proportion of these were inhabitants of London of Indian ancestry, who according to the authors are at high risk for obesity and metabolic diseases. In a first step with 5,387 samples, the research team identified 207 gene loci that were epigenetically altered dependent on the BMI. They then tested these candidate loci in blood samples of an additional 4,874 subjects and were able to confirm 187 of these. Further studies and long-term observations also indicated that the changes were predominantly a consequence of being overweight – not the cause.

Significant changes were found in the expression of genes responsible for lipid metabolism and substrate transport, but inflammation-related gene loci were also affected. From the data, the team was also able to identify epigenetic markers that could predict the risk of type 2 diabetes.

Original publication:
Wahl, S. et al. (2016): Epigenome-wide association study of body mass index, and the adverse outcomes of adiposity. Nature, doi:10.1038/nature20784