Keeping blood sugar levels steady may help lower the risk of developing Alzheimer’s disease and other forms of dementia. That’s the key finding from a new study published in JAMA Network Open, which looked at older adults with diabetes.
The research focused on a measure called HbA1c, which shows the average blood sugar level over the past two to three months.
Doctors often use HbA1c to see how well someone is managing their diabetes. In this study, scientists looked at how much time each person’s HbA1c levels stayed within a personalized target range. This is known as “time in range” or TIR.
Researchers from Boston College, led by Dr. Patricia C. Underwood, studied over 374,000 older veterans with diabetes. They followed these patients for up to 10 years, using healthcare data from 2005 to 2014.
They found that people whose blood sugar stayed within their target range more often were less likely to be diagnosed with Alzheimer’s disease or related dementias. The risk of dementia went up as the time in range went down.
In fact, people who had their HbA1c levels in range less than 20% of the time had about a 19% higher risk of developing dementia compared to those who kept it in range 80% or more of the time.
The researchers also looked at whether it mattered if someone’s blood sugar was often too high or too low. They discovered that spending more time with blood sugar levels below the target range was linked to an even higher risk of dementia.
This finding held true even when they removed people who were taking medicines known to cause low blood sugar, like insulin and sulfonylureas.
This study supports the idea that blood sugar stability—not just keeping it low—is important for brain health. For older adults with diabetes, it may be safer and more helpful to avoid both high spikes and low crashes in blood sugar.
The authors of the study suggest that doctors should work with patients to set personal HbA1c goals based on their age, other health conditions, and life expectancy. They say that focusing on keeping blood sugar levels stable within that target range could help reduce the risk of dementia in older people with diabetes.
In summary, this study adds strong evidence that managing diabetes carefully can have major benefits for brain health later in life. It highlights the need for a balanced approach—avoiding both high and low blood sugar levels—to protect memory and thinking abilities.
If you care about Alzheimer’s disease, please read studies about the protective power of dietary antioxidants against Alzheimer’s, and eating habits linked to higher Alzheimer’s risk.
For more health information, please see recent studies that oral cannabis extract may help reduce Alzheimer’s symptoms, and Vitamin E may help prevent Parkinson’s disease.
Copyright © 2025 Knowridge Science Report. All rights reserved.
