A new study in JAMA finds that people who are treated for type 2 diabetes have higher incidence rates of elevated depressive symptoms. In the same article, researchers report a modest association between the risk of diabetes and persons with depression.
It is known that compared to the general population, people with diabetes are more likely to have elevated depressive symptoms and higher rates of clinical depression. The direction of the relationship between diabetes and depression is still unclear: Are diabetic individuals at an increased risk of depressive symptoms? Are people with depressive symptoms at an increased risk of developing type 2 diabetes? or both? Though it remains unclear if type 2 diabetes is a risk factor for increased symptoms of depression, the authors write that, “A diagnosis of diabetes or the burden of dealing with its complications might also lead to symptoms of depression.”
Further investigating the link between diabetes and depression, Sherita Hill Golden, M.D., M.H.S. (Johns Hopkins University, Baltimore) and colleagues studied men and women age 45 to 84 years who enrolled in a study between 2000 and 2002 and were followed up between 2004 and 2005. The researchers tested the directional relationship between depressive symptoms and type 2 diabetes by analyzing the fasting blood glucose levels and depressive symptoms. High scores on the Center for Epidemiologic Studies Depression Scale (CES-D), use of anti-depressant medications, or both were used as indications of elevated depressive symptoms. The blood glucose levels were used to categorize each patient as having normal fasting glucose, impaired fasting glucose, or type 2 diabetes.
The first analysis (Analysis 1), consisting of 5,201 participants without type 2 diabetes at baseline, was designed to measure the relative risk of developing type 2 diabetes over 3.2 years and how these risks differ between those with and without depressive symptoms. The second analysis (Analysis 2), consisting of 4,847 participants without elevated depressive symptoms at baseline, was designed to estimate the relative odds of developing depressive symptoms over 3.1 years and how these risks differ for those with and without type 2 diabetes.
The analysis revealed a 52% higher risk of developing elevated depressive symptoms for those with treated type 2 diabetes. However, no increase in risk was noted for individuals with untreated type 2 diabetes.
Analysis 1 indicated that over 3.2 years, the incidence of type 2 diabetes among those with and without elevated depressive symptoms was 22.0 and 16.6 per 1,000-person years, respectively. Statistically, these figures present a significant association between higher levels of depressive symptoms and the incidence of diabetes. After adjusting for lifestyle factors, however, the association was not found to be statistically significant.
The authors note that, “Our findings of an association in participants with treated but not untreated type 2 diabetes suggests that the psychological stress associated with diabetes management may lead to elevated depressive symptoms.” In reference to the association between depression and the development of diabetes, they remark: “Depressive symptoms are associated with several metabolic and behavioral risk factors for type 2 diabetes… depressed individuals are less likely to comply with dietary and weight loss recommendations and more likely to be physically inactive, contributing to obesity, a strong risk factor.”
“The present study contributes to a growing body of literature indicating a bidirectional association between these 2 serious long-term diseases. Future studies should determine whether interventions aimed at modifying behavioral factors associated with depression will complement current type 2 diabetes prevention strategies. Finally, these findings suggest that 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,” conclude the authors.
Examining a Bidirectional Association Between Depressive Symptoms and Diabetes
Sherita Hill Golden; Mariana Lazo; Mercedes Carnethon; Alain G. Bertoni; Pamela J. Schreiner; Ana V. Diez Roux; Hochang Benjamin Lee; Constantine Lyketsos
JAMA (2008). 299[23]: pp. 2751 – 2759.
Written by: Peter M Crosta