Depression may be a direct cause of type 2 diabetes

New genetic research has revealed that depression may be a direct cause of type 2 diabetes, according to scientists from the UK.

The two conditions have always been linked: People with type 2 diabetes are about twice as likely to be diagnosed with depression compared to other people.

However, it was never clear whether type 2 diabetes caused depression, or the other way around — or if other factors, such as obesity, were involved.

Now, researchers have discovered seven genetic variants that contribute to both conditions. These genes play a role in insulin production and in inflammation in the brain, pancreas and fatty bodily tissue.

Changes caused by the genes inside the body can partly explain the processes involved in depression and how it increases the risk of developing type 2 diabetes.

“This hugely important study gives us new insights into the links between genetics, type 2 diabetes and depression, indicating that depression can contribute to the development of type 2 diabetes,” Dr. Elizabeth Robertson, director of research at Diabetes UK, said in a statement.

“Type 2 diabetes is complex, with multiple risk factors — and previous research has shown that the condition is more common in people with depression,” Robertson added.

“This study gives us greater insight into why and indicates that depression should now be considered a risk factor for type 2 [diabetes].”

The researchers combed through genetic data from hundreds of thousands of people in the UK and Finland, including 19,000 people with type 2 diabetes, 5,000 diagnosed with depression and 153,000 who self-reported having depression.

Their analysis, published in the journal Diabetes Care, revealed that only 36.5% of the effect of depression on type 2 diabetes could be explained by obesity.

And medical experts still believe that living with type 2 diabetes may be one of several factors in developing depression, even though a direct cause for diabetes causing depression wasn’t found in this latest study.

Because depression, type 2 diabetes and obesity are inextricably linked, the researchers hope that their study will encourage health care providers to screen their patients with depression for type 2 diabetes and other related conditions.

“Our discovery illuminates depression as a contributing cause of type 2 diabetes and could help to improve prevention efforts,” said professor Inga Prokopenko of the University of Surrey, who led the research effort.

“The findings are important for both individuals living with the conditions and health care providers, who should consider implementing additional examinations to help prevent type 2 diabetes onset in people suffering from depression.”