Study: Having Diabetes May Double Your Risk of Alzheimer’s

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Nerve cells in an Alzheimer's brain

Adding to the evidence that a healthy body makes for a healthy mind, a study from Japan finds that people with diabetes may be at increased risk of developing Alzheimer’s disease and other kinds of dementia.

The study followed more than 1,000 adults aged 60 or older, none of whom had memory problems at the start of the study. The researchers determined the participants’ diabetes status using a glucose-tolerance test in the clinic: at the start, 15% had diabetes, while 23% had prediabetes.

About 11 years later on average, the researchers examined participants for evidence of dementia. In all, 232 people had developed Alzheimer’s or other forms of dementia, and the researchers found that people with diabetes had about twice the risk of people without.

Prediabetic people also showed an increased risk of dementia, and the association persisted after researchers accounted for other factors that contribute to cognitive decline, including age, blood pressure and body mass index.

MORE: Could a Spray of Insulin Help Treat Alzheimer’s?

A growing body of research links diabetes with Alzheimer’s and dementia, but the exact mechanism isn’t yet clear. Scientists have some theories, though. reported:

Diabetes could contribute to dementia in several ways, which researchers are still sorting out. Insulin resistance, which causes high blood sugar and in some cases leads to type 2 diabetes, may interfere with the body’s ability to break down a protein (amyloid) that forms brain plaques that have been linked to Alzheimer’s. High blood sugar (glucose) also produces certain oxygen-containing molecules that can damage cells, in a process known as oxidative stress.

In addition, high blood sugar — along with high cholesterol — plays a role in the hardening and narrowing of arteries in the brain. This condition, known as atherosclerosis, can bring about vascular dementia, which occurs when artery blockages (including strokes) kill brain tissue.

Researchers can’t say that you’ll prevent Alzheimer’s by preventing diabetes, but if overall good health is what you’re after, there’s no harm in following the standard advice: keep your weight down, exercise, don’t smoke, eat a healthy diet.

If you have diabetes, get your blood sugar under control. Also, get checked for high blood pressure and high cholesterol.

The current study was published in Neurology.

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