Clarifying The Link Between Diabetes And Depression

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.

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Written by: Peter M Crosta