Poor Glycemic Control Associated With Higher Risk for Dementia in Older Adults With T1D

HbA1c lab result
HbA1c lab result
Repeated exposure to high levels of HbA1c was associated with increased risk for dementia in a cohort of patients age ≥50 with type 1 diabetes.

Cumulative exposure to high levels of glycated hemoglobin (HbA1c) was associated with an increased risk for dementia in older adults with type 1 diabetes (T1D), according to findings published in Diabetes Care. Conversely, cumulative exposure to well-controlled HbA1c was associated with a lower risk for dementia in this population.

Researchers investigated the association between long-term glycemic control and dementia in older individuals with T1D. A cohort of 3433 members of a healthcare system age ≥50 with T1D was followed from 1996 to 2015. Repeated measurements of HbA1c, dementia diagnoses, and comorbidities were obtained from medical records for use in the study.

At a mean follow-up of 6.3 years, 155 participants (4.5%) were diagnosed withdementia. Patients with ≥50% of HbA1c measurements at 8% to 8.9% (64 to 74 mmol/mol) had a 65% increased risk for dementia and HbA1c measurements at ≥9% (75 mmol/mol) were associated with a 79% higher risk for dementia. 

These findings were in comparison with patients with <50% of measurements exposed to high levels of HbA1c (HbA1c 8% to 8.9%; adjusted hazard ratio [aHR], 1.65; 95% CI, 1.06-2.57 and HbA1c ≥9%;  aHR, 1.79; 95% CI, 1.11-2.90). Conversely, patients with ≥50% of HbA1c measurements at 6% to 6.9% (42 to 52 mmol/mol) and 7% to 7.9% (53 to 63 mmol/mol), classified as well-controlled HbA1c levels, had a 45% lower risk for dementia (HbA1c 6% to 6.9%; aHR 0.55; 95% CI, 0.34-0.88 and HbA1c 7 to 7.9% aHR, 0.55; 95% CI, 0.37-0.82).

“Our findings suggest glycemic control as an important and potentially modifiable factor

that can be targeted to reduce dementia risk among older adults with type 1 diabetes,” the investigators concluded.

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Lacy ME, Gilsanz P, Karter AJ, Quesenberry CP, Pletcher MJ, Whitmer RA. Long-term glycemic control and dementia risk in type 1 diabetes [published online September 4, 2018]. Diabetes Care. doi:10.2337/dc18-0073