As in earlier reports, the diabetes patients with major depression tended to be slightly younger, heavier, have more co-existing medical conditions, and were more likely to be treated with insulin than were diabetes patients without depression. They also had higher levels of a substance in the blood formed when the sugar glucose attaches to hemoglobin, an oxygen-carrying protein. The major depression group had a higher proportion of women and smokers. However, after controlling for these differences between depressed and non-depressed patients with diabetes, the increased risk of complications associated with depression remained.

Several previous studies suggest the negative relationship between depression and diabetes cuts both ways. People with depression are prone to diabetes, and vice versa. Impairment from diabetes, such as blindness or kidney failure requiring long-term dialysis, interferes with a person's daily life and can be overwhelming. The person may become depressed or an existing depression may worsen.

As the incidence of type 2 diabetes soars, the clinical and public health significance of these findings increases, the authors noted. Further research is needed, the authors added, to clarify the underlying biological mechanism for the association between depression and complications of diabetes, and to test interventions which might be effective in lowering the risk of complications among patients who have both diabetes and depression.

Source: University of Washington