Evolutionary changes produce increased diabetes risk today, study finds

Genetic variations that occurred in humans' long distant past as a result of evolutionary demands may now be placing more individuals at risk for developing type 2 diabetes, according to a new study from Stanford University. The findings may help doctors better understand patients' diabetes risks based on genetic and environmental factors.

The researchers reported in the journal Diabetes that they became interested in uncovering historic reasons for diabetes susceptibility when they looked at regions of DNA that have come to be associated with an increased risk. Certain genetic variations drastically increase an individual's risk for the disease. The team wanted to understand how evolutionary forces led to the proliferation of these genes.

They focused their research on the GIP gene, which has been associated with stimulating insulin production after meals and comes in two variations. The newer variation is more common in Asian and European populations than it is in African ones, which indicates that it has adapted over time to new environments.

Individuals who have the variation are more likely to experience high fasting blood sugar levels, which increases the risk of type 2 diabetes. While this is a disadvantage in today's society, the researchers speculated that it may have been more useful when food was less secure.

The variation started to emerge around that the time that Western populations began moving to agriculture-based societies. Food supplies could have been less stable during this period, so higher blood sugar levels helped sustain energy levels through times of drought and famine.

While the findings may be interesting for historic reasons, this is far from their only utility. The researchers said that the improved knowledge of evolutionary factors that led to this increased type 2 diabetes risk could help doctors understand the interplay of genetic and environmental factors in today's diabetes patients.