Type 2 Diabetes Genetic Research

Written by Bonnie Sanders Polin PhD

Type 2 Diabetes Genetic Research
Headlines this week start with a DNA sweep which found new links to type 2 diabetes. Two studies published online in the journal Nature Genetics this week were the results of hundreds of scientists sifting through genetic data from 122,000 people.

The results quintupled the number of gene variants known to boost the risk of type 2 diabetes. A consortium of researchers first isolated 10 gene mutations that help the body's ability to regulate blood glucose and insulin levels.

In a companion study, the same consortium—pooling the resources of more than 100 institutions in Europe, Canada, Australia, and the United States—determined that two of these newly-identified variants directly influence the risk of diabetes. One gene in particular known as GIPR-A was found to play a prominent role.

The researchers hope that these new pathways will lead to new treatments for type 2 diabetes; however, they note that to date they have identified only 10% of the genetic contribution to glucose levels in nondiabetic people. They acknowledged that they need to examine the possible more complex or rare forms of gene variation, along with the role of gene-environment interaction in causing type 2 diabetes.

For the medical community, this is important work, as it is thought that 220 million have diabetes, and it is hypothesized that the number of deaths could double from 1,000,000 per year presently to 2,000,000 between 2005 and 2020.

To learn more about the study that identified GIPR-A as an important gene, go here.

Diabetes and Depression: Is There a Connection?
The January issue of Diabetes Care has an article titled "Diabetes Distress but Not Clinical Depression or Depressive Symptoms Is Associated with Glycemic Control in Both Cross-sectional and Longitudinal Analysis" by Lawrence Fisher, PhD et al.

The researchers attempted to determine the concurrent, prospective, and time-concordant relationships among major depressive disorder (MDD), depressive symptoms, and diabetes distress with lack of glycemic control.

They assessed 506 type 2 diabetes patients for MDD, depressive symptoms, diabetes distress, along with self-management, stress, demographics, and diabetes status, at baseline, and at 9 and 18 months later. They explored the cross-sectional relationships of baseline variables with changes in A1c over time, and time-concordant relationships with A1c.

They found that all 3 variables were moderately intercorrelated, although the relationship between depressive symptoms and diabetes distress was greater than the relationship of either with MDD.

In the cross-sectional research, only diabetes distress but not MDD or depressive symptoms were significantly associated with A1c. None of the three variables were linked with A1c in prospective analysis. Only diabetes distress displayed significant time-concordant relationships with A1c.

The researchers concluded that what has been called "depression" among type 2 diabetics may really be 2 conditions, MDD and diabetes distress, with only the latter displaying significant associations with A1c. They suggested ongoing evaluation of both diabetes distress and MDD may be important in clinical settings.

Read more about the study here.

Diabetic Diet: What Should You Eat?
The January issue of Diabetes Care also has an article titled "Dietary Intake of Total Animal and Vegetable Protein and Fat and Risk of Type 2 Diabetes in the European Prospective Investigation into Cancer and Nutrition (EPIC)-NL Study" by Ivonne Sluijs, MSC et al.

Dietary recommendations in the past focused mainly on dietary fat and carbohydrate content in relation to diabetes risk. Meanwhile, high protein diets may contribute to glucose metabolism disturbance but the evidence is scarce.

The researchers examined records of 38,094 participants enrolled in the (EPIC)-NL study. During the 10 years follow-up, 918 incident cases of diabetes were documented. Diabetes risk increased with higher total protein and animal protein intake. Vegetable protein was not related to diabetes. Consuming 5% energy from total or animal protein at the expense of 5% energy from carbohydrates or fat increased diabetes risk.

The researchers concluded that diets high in animal protein aer associated with an increased diabetes risk. Their findings also suggest a similar association for total protein itself instead of only animal sources. They suggest that accounting for protein content in dietary recommendation for diabetes prevention may be helpful.

Learn more about the study's conclusions here.