Type 1 diabetics face increased risk of dementia in later life

by Barbara Hewitt on July 24, 2015

People with type 1 diabetes may face an increased risk of developing thinking and memory problems as they age compared to the general population, new research has found.

The 12 year study carried out by researchers in the United States found that people with type 1 diabetes were 83% more likely to develop dementia as they aged and the scientists now want to work on what can be done to help them.


Although there are strong links between type 2 diabetes and dementia, this is the first study to find similar links with type 1

Although there are strong links between type 2 diabetes and dementia, this is the first study to find similar links with type 1. Previous research has, however, found links between type 1 diabetes and cognitive decline.

The study was conducted by examining the records of 490,000 patients who were over the age of 60. Of these patients, 334 had type 1 diabetes. None of the 490,000 had dementia at the beginning of the study.

During the 12 year study period some 16% of the 334 type 1 patients developed dementia, compared to 12% of the 490,000 cohort. Of the patients who had type 2 diabetes, 15% developed dementia.

‘Our study found a modestly higher risk of all-cause dementia in people with type 1 diabetes. The next step is to figure out what that means, and how we can help people with type 1 diabetes age successfully,’ said study author Rachel Whitmer, senior scientist in the division of research at Kaiser Permanente in Oakland, California.

However, Whitmer also noted that the study doesn’t prove that type 1 diabetes caused dementia, only that the two diseases were linked. ‘This is an observational study that shows association, not causation. We don’t have tissue from these people’s brains,’ she explained.

When the researchers removed people with type 2 diabetes from the general population sample, the association between type 1 diabetes and dementia became even stronger. However, when the researchers further adjusted the data to account for factors such as sex, age, race, stroke, peripheral artery disease and high blood pressure, the link between type 1 diabetes and dementia decreased.

After these adjustments, people with type 1 diabetes were 73% more likely to have dementia than the rest of the group and Whitmer said it’s possible that as in type 2 diabetes, high blood sugar levels may cause some sort of damage to blood vessels that could contribute to dementia in people with type 1 diabetes. But the reason behind the association isn’t clear from this study, and more research is needed.

Helen Nickerson, the director of translational research for diabetes charity JDRF, said that while the current study does find an association, it raised more questions than it answered. For example, she said, do people with better blood sugar management have less dementia than people whose blood sugar is less well controlled? She said it’s also important to note that the study’s type 1 diabetes sample size wasn’t large.

‘Some people with type 1 have insulin resistance to varying degrees in addition to type 1 diabetes, and that may be the connection. It’s something important to look at,’ she added.

Whitmer pointed out that it is important that this issue is on the radar of clinicians. ‘Type 1 diabetes is a disease that requires constant vigilance and constant self-care. We need to understand how cognition is affected with age,’ she explained.

Both experts also pointed out that this study population was born in the 1940s or earlier, and likely diagnosed with type 1 diabetes quite a while ago. Management of the disease has changed significantly since then, so these findings may not apply to people who’ve been diagnosed with type 1 diabetes more recently.

The opinions expressed in this article do not necessarily reflect the views of the DiabetesForum.com Community and should not be interpreted as medical advice. Please see your doctor before making any changes to your diabetes management plan.

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