Research Predicts Dementia Risk for Diabetics

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Harvard Medical School
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Research Predicts Dementia Risk for Diabetics

News Review From Harvard Medical School

August 20, 2013

News Review From Harvard Medical School -- Research Predicts Dementia Risk for Diabetics

Researchers say they have found a way to predict the risk of dementia for older adults with diabetes. The risk score was developed using information about nearly 30,000 people. All of them were age 60 or older and had type 2 diabetes. During a 10-year period, about 17% developed dementia. Researchers found that age, education level and six health problems were the strongest predictors of dementia. The problems included diabetic foot or eye disease and events of dangerously high or low blood sugar. These are all directly caused by diabetes. Most of the other conditions also are more common among diabetics. They included heart disease, depression, and stroke or related problems with circulation in the brain. Each risk factor was assigned a point total. Then researchers created a scoring system. People with the highest scores were 37 times more likely to develop dementia within 10 years than those with the lowest scores. Researchers tested the system in a different group of older patients with diabetes. They found that it predicted dementia accurately for this group, too. The journal Lancet Diabetes & Endocrinology published the study online August 20. HealthDay News wrote about it.


By Lori Wiviott Tishler, M.D
Harvard Medical School


What Is the Doctor's Reaction?

Patients who come to see me often complain of being forgetful or having trouble finding words. Most of the time, these complaints are related to normal aging. Behind the questions, however, is the patient's very real fear that he or she might be developing dementia. Most of us have known someone with dementia -- a parent, a grandparent or a friend.

I explain to patients that there is no "test" for dementia and that their symptoms probably don't indicate anything bad. Yet people often want to better understand their risk of dementia. 

This study looked at the development of dementia in people with type 2 diabetes. Both illnesses are very common in our aging population. In fact, the risk of dementia is doubled in people who also have type 2 diabetes. The authors created and tested a prediction score to show which people with diabetes would have the greatest risk of developing dementia in a 10-year period.

The authors looked for conditions that would increase the risk of dementia. They used these conditions to create a dementia risk score. In this study, people with a low score had a 5% risk of developing dementia over 10 years. People with higher scores had a more than 70% risk of developing dementia in the same period.

The risk factors included in the prediction score included the following:

  • Age
  • Low level of education
  • Microvascular disease (such as diabetic retinopathy, a disease of the blood vessels in the eye)
  • Diabetic foot  problems
  • Cerebrovasclar disease (such as a stroke)
  • Heart disease
  • Depression
  • Metabolic disease (such as long episodes of low blood sugar)

All of these factors increased the risk of dementia. The study designers gave each of them a point score.

One strength of the study was the large number of people from diverse backgrounds used to develop the model. Another strength was that researchers tested the model on more than 2,000 other people to validate the scores. The factors used to develop the model are very easy to measure in a general clinical setting. They don't require any extra costly studies or procedures.

Diagnosis of dementia was made from diagnostic codes. The researchers didn't confirm the diagnosis with chart reviews or exams. This might lead to diagnosis of too many cases or too few. The authors also made clear that this prediction model applies only to adults over the age of 60 who have type 2 diabetes.

This study is really intriguing. It puts together a very interesting, cost-effective model for thinking about which people with diabetes are at greatest risk of dementia.

It stands to reason that we might work more aggressively to change risk factors in people at higher risk for dementia. Patients at particularly high risk might also be good candidates for future research studies. As a related commentary points out, treatments for dementia remain elusive. So the data generated from this risk calculator may, for some time, prove to be more useful to researchers than to practicing doctors or patients.


What Changes Can I Make Now? 

This study seems to provide some proof that people with type 2 diabetes and further health problems caused by diabetes are at higher risk for dementia. However, it doesn't prove that preventing these further health problems (known as complications) would decrease the risk of dementia.

Still, for people over 60 years old with diabetes, avoiding diabetic complications makes sense for overall health and quality of life. That's true even if we don't (yet) have proof that it could also prevent dementia.

If you have diabetes, take good care of yourself by understanding your diabetes:

  • Do you know how to monitor your blood sugar?
  • Do you know what your target blood sugar levels should be?
  • Do you know how to exercise and eat right for yourself?
  • Do you see the eye doctor each year?  The foot doctor (podiatrist)?

If you have diabetes and you're not taking good care of yourself, then the four points above are a good place to begin. It's never too late to take control of your health.

If you are concerned about dementia for yourself or a loved one, see your doctor. The doctor will ask you some questions in the office to determine your risk. If your doctor is worried, he or she might refer you for more tests, depending on the level of concern. Most forms of dementia can't be reversed. But some are treatable, so it makes sense to seek help.


What Can I Expect Looking to the Future? 

Based on the interesting prediction rule developed by this study, I am looking forward to further related research. I hope we can see some studies that look at whether preventing diabetic complications can also reduce the risk of dementia. Learning that would be such an important lesson for our aging population!


Last updated August 20, 2013

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