Both diabetes and clinical depression are known to be risk factors for dementia. Now a study that tracked nearly 4000 diabetics over 5 years has found having both increased the risk 2.7-fold. Nearly 8% of the diabetics with major depression (36 of 455) developed dementia over the five years, compared to 4.8% of those with diabetes alone (163 of 3382). Those who developed dementia within 2 years of being diagnosed with depression were excluded. Depression is common among people who have diabetes.
Reference:
[338]
(2010). Comorbid Depression Is Associated with an Increased Risk of Dementia Diagnosis in Patients with Diabetes: A Prospective Cohort Study.
Journal of General Internal Medicine. 25(5), 423 - 429.