Newly diagnosed type 2 diabetes and risk of dementia: a population-based 7-year follow-up study in Taiwan.

Background: Diabetes is associated with an increased risk of developing dementia. However, data on the patients with newly diagnosed type 2 diabetes are limited.

Objective: To investigate the relationship between newly diagnosed type 2 diabetes and the risk of developing dementia, ischemic stroke and intracranial hemorrhage after disease diagnosis and the interrelationship between dementia and the stroke events.

Method: Data were collected from the National Health Insurance Research Database of Taiwan. The study cohort included 3717 patients newly diagnosed with type 2 diabetes and 37,170 age- and sex-matched comparison patients from the same period. All patients were tracked for 7 years following their index visit in 2000-2001.

Result: After adjusting for potential confounders, dementia risk was approximately 63% higher (hazard ratio [HR], 1.63; 95% CI, 1.33-1.99) among newly diagnosed type 2 diabetic patients than among comparison subjects. Newly diagnosed type 2 diabetes also increased the risk of developing ischemic stroke but not intracranial hemorrhage. About 43.6% of diabetic patients who developed dementia also had ischemic stroke during the follow-up period, higher than the rate 29.6% in the comparison group.

Conclusion: This study shows that newly diagnosed type 2 diabetes is associated with a 63% higher future risk of dementia during the 7-year follow-up period. The high dementia and ischemic stroke overlap rate in the diabetic study group suggests vascular events play an important role in the pathogenesis of developing dementia.