Monday, June 30, 2008

More On The Diabetes-Depression Link

People with diabetes experience depression more often than people without diabetes.

Does having diabetes raise your risk of developing depression? Or is it the other way around ... Does experiencing depression raise your risk of developing diabetes?

No definitive answer to that question exists. In fact, the two may be inextricably intertwined. That did not deter a group of Johns Hopkins researchers from seeking to tease the two conditions apart. Their findings were reported in the June 18 issue of JAMA:

Examining A Bidirectional Association Between Depressive Symptoms And Diabetes

The study had two parts. The cohort used was the Multi-Ethnic Study of Atherosclerosis (MESA study), a group of US adults followed for about 3 years.

The first part involved 5201 participants without diabetes. Their findings:
"The crude incidence of type 2 diabetes over 3.2 years was 22.0 per 1000-person years for those with elevated depressive symptoms and 16.6 per 1000 person-years for those without elevated depressive symptoms."
So, there was a small increase in risk for diabetes in individuals experiencing depression. This difference, however, was partially lessened when lifestyle factors (smoking history, caloric intake, alcohol use, physical activity level) were considered. It is possible that the same lifestyle factors that put someone at risk for depression (physical inactivity, higher caloric intake with weight gain), also increase their risk for diabetes.

The second part involved 4847 participants without depressive symptoms. Their findings:
"Individuals with untreated type 2 diabetes were not at increased risk of developing elevated depressive symptoms, those with treated type 2 diabetes were at increased risk of developing elevated depressive symptoms. ... Treated type 2 diabetes was associated with a 52% higher odds of developing elevated depressive symptoms."
That last finding, where untreated patients did not experience depression but treated patients did, led the authors to conclude:
"Clinicians should be aware of increased risk of elevated depressive symptoms in individuals with treated type 2 diabetes and consider routine screening for depressive symptoms among these patients."
What is it about treatment for diabetes that raises risk for depression?

The authors speculate that psychological stress associated with diabetes management may contribute. Also, if you're being treated, you're likely to have a number of complications which by themselves could increase the risk for depression.