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Controlling Dementia Risk for People Who Have Type 1 Diabetes

Nov 10, 2018
Editor: Joy Pape, MSN, FNP-C, CDE, WOCN, CFCN, FAADE

Author: Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy

Dementia rates are higher among people who have type 1 diabetes and an A1C>8%.

Diabetes can cause micro- and macrovascular complications like retinopathy, neuropathy, nephropathy, stroke, and coronary artery disease. Elevated A1C  is associated with more of these complications. Glycemic management has also been linked to cognition issues in type 2 diabetes, but not much research has shown the effect of glycemic management on people with type 1 diabetes. There is even less research on type 1 diabetes and risk of developing age-related diseases like dementia. According to the following study, dementia is linked to poor glucose management in people with type 1 diabetes.


Using a diabetes registry from Kaiser Permanente Northern California, researchers pulled a sample of patients who were over 50 years of age and had type 1 diabetes. Those with dementia or no HbA1c levels were excluded. Dementia diagnoses was based on electronic medical records. A diagnosis code for Alzheimer’s disease, nonspecific dementia, and vascular dementia indicated patient-developed dementia. Every HbA1c that was recorded from the patients was used to place the patient in the following categories: <6%, 6-6.9%, 7–7.9%, 8–8.9%, and >9%. Patient demographics and comorbidities were examined with dementia status using chi square and t tests. Cox proportional hazards were used to estimate the association between the categories of HbA1c and risk of dementia.

A total of 3,433 patients were followed for an average of 6.3 years. Of those followed, 155 individuals developed dementia, 519 died without a dementia diagnosis, 1,899 did not have a dementia diagnosis at end of the study, and 860 patients left the study for more than 90 days. The mean age of those who developed dementia was 64.6 years.

It was determined that dementia risk was higher in patients with an HbA1c above 8%. Those with prolonged exposure to an HbA1c at 8-8.9% or >9% were 2.51 or 2.13 times more likely to develop dementia, respectively. A prolonged HbA1c exposure at 6-6.9% and 7-7.9% was associated with 58% and 61% lower risk of dementia, respectively. In age-adjusted models, majority exposure to HbA1c <6% was associated with increased dementia risk, but in fully adjusted models there was no significant link. Dementia risk was 60% lower in those with longer exposure to a controlled HbA1c of 6-7.9% than those with minimal time at a controlled HbA1c.

Long-term glycemic management is critical in maintaining cognitive function. Looking at this study and previous studies shows that people with type 1 diabetes are at an increased risk of developing dementia but long-term blood glucose management can reduce this risk.

Practice Pearls:

  • Glycemic management can help maintain cognitive function in people with type 1 diabetes.
  • Age and diabetes have an impact on development of dementia, but keeping HbA1c under 7.9% for long periods of time can reduce this risk.
  • By keeping blood glucose managed,, patients can avoid many health complications and decrease the risk of developing dementia.


Mary E. Lacy, Paola Gilsanz, AndrewJ.Karter, Charles P.Quesenberry, Mark J. Pletcher, and Rachel A. Whitmer. Long-term Glycemic Control and Dementia Risk in Type 1 Diabetes. Diabetes Care. (2018) https://doi.org/10.2337/dc18-0073

Angela Reyes, Pharm.D. Candidate, LECOM College of Pharmacy