People being treated with type 2 diabetes are at a heightened risk for developing depression while those with depression are also likely to develop diabetes, said a study in the Journal of the American Medical Association Wednesday.

The study indicated that the relationship between type 2 diabetes, the form of the disease closely linked to obesity and sedentary lifestyle, may be a bit like a two-way highway.

Dr. Sherita Hill Golden of Johns Hopkins University, Baltimore, and colleagues used measures of fasting blood glucose and depressive symptoms to test whether elevated depressive symptoms predicted incident type 2 diabetes and whether participants with type 2 diabetes at the beginning of the study were more likely to develop increased symptoms of depression than participants without diabetes.

The study included men and women age 45 to 84 years who enrolled in 2000-2002 and were followed up until 2004-2005.

Elevated depressive symptoms were defined by high scores on the Center for Epidemiologic Studies Depression Scale (CES-D; a questionnaire given to participants), use of anti-depressant medications, or both. Participants were categorized as having normal fasting glucose, impaired fasting glucose or type 2 diabetes.

They found that people with symptoms of depression were 42 percent more likely to develop diabetes by the end of the study than those without such symptoms. They also found that the more serious the symptoms, the higher the risk of diabetes.

The researchers statistically accounted for factors including obesity, lack of physical activity and smoking, and found that the risk for diabetes was still 34 percent higher in patients with depression.

"When we looked at the people in our study who had elevated symptoms of depression, they were more likely to eat more calories, they exercised less, and they were more likely to be current smokers. And as a consequence, they were also more obese," Golden said.

"And those are all known risk factors for type 2 diabetes. So it seems that some of the adverse health behaviors associated with depressive symptoms were an important component of that relationship (between depression and diabetes)."

The findings suggest that integration of care may be helpful to these patients, Golden said.

"For people who are being treated for symptoms of depression, it's important also to think about some treatment modalities that can also help them adopt healthy behaviors," she said. "And certainly among people who have treated diabetes and who are at risk of developing depression, we need to be aware of that increased risk."

(Agencies via Xinhua June 18, 2008)