Study links high blood sugar to dementia

Physicians have previously suspected a link between diabetes and dementia, though the actual physical cause hasn’t been clear. Now, a new study links high blood sugar levels, even in those without a diabetes diagnosis, to mental decline.

The study results were published Thursday in the New England Journal of Medicine. For the study, researchers at the University of Washington tracked 2,067 members of an HMO for nearly 7 years. Annual glucose tests were taken during their routine medical exams.

Though none had dementia prior to the study, the condition developed in 524—more than a quarter of the participants—over the course of the research. Of these, 450 did not have diabetes. The scientists found those with a higher than average blood sugar levels had an 18 percent increased risk of developing dementia, including Alzheimer’s disease, than those whose blood glucose measured slightly lower.

Those with diabetes had an even greater risk of dementia, by as much as 40 percent, according to the study.

“Though this is an observational study, meaning the researchers aren’t looking for a specific physical cause for the findings, I’m not surprised by the results,” says Dr. Daniel Litoff, geriatrician with Advocate Illinois Masonic Medical Center in Chicago. “Elevated blood sugar has been linked to cardiac disease. It’s thought that the damage to the blood vessels in the brain, caused by the high blood sugar, leads to dementia later in life.”

Dr. Litoff recommends combating high blood sugar with a healthy lifestyle—no smoking, adding exercising and maintaining a healthy body weight. Keeping physically and mentally active has been shown to postpone dementia, he says.

“Keeping healthy as we age is really the best deterrent of dementia,” Dr. Litoff says. “No one should be surprised to hear that.”