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.
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