A new study, published in the journal JAMA Network Open, indicates that maintaining more stable hemoglobin A1c (HbA1c) levels over time in ranges tailored to individuals is associated with a lower risk of developing Alzheimer’s disease and related dementias in older adults.
The researchers say this could help doctors identify people with diabetes who are at a higher risk of Alzheimer’s. Dementia is a common issue for older adults with diabetes and research shows that people with diabetes are more likely to develop Alzheimer’s disease and other dementias than those without diabetes.
The A1C test, also known as the hemoglobin A1C or HbA1c test, is a blood test that measures a person’s average blood sugar levels over the past three months. It is used to diagnose and monitor diabetes.
Diabetes guidelines suggest tailoring blood sugar targets for older adults based on their life expectancy, other health conditions, and diabetes-related complications. Healthcare professionals often aim to find a balance by setting less strict HbA1c targets to avoid low blood sugar while also keeping an upper limit to prevent high blood sugar and its complications.
However, a newer measure — HbA1c time in range (TIR) — which is what this study examined, looks at how stable blood sugar levels are over time within certain ranges.
Higher HbA1c TIR indicates better blood sugar stability, whereas lower HbA1c time in range reflects more instability in blood sugar levels. This measure might more accurately reflect the link between blood sugar control over time and the risk of developing dementia.
For this study, researchers examined the association between HbA1c TIR and Alzheimer’s Disease and Related Dementias (ADRD) in a large group of older veterans with diabetes across the country.
The researchers calculated HbA1c time in range (TIR) as the percentage of days during the baseline period when HbA1c levels were within personalized target ranges based on clinical factors and life expectancy. Higher HbA1c TIR was considered better.
The study included 374,021 veterans with diabetes, with an average age of 73.2 years, and 99% were male. Over a follow-up period of up to 10 years, 11% (41,424) developed ADRD. We studied older adults with diabetes who had hemoglobin A1c levels measured over time. For each person, researchers determined a clinically appropriate range for their A1c levels. They then measured the percentage of time that A1c levels were in this target range over 3 years.
The study supports the idea that living a heart-healthy lifestyle can protect our cognitive health and suggests that maintaining our A1c, a marker of the presence and severity of diabetes, in an acceptable range as determined by our doctor lowers the risk of cognitive decline and dementia due to Alzheimer’s disease.
