Severe Low Blood Sugar Ups Older Diabetics' Dementia Risk

April 14 -- TUESDAY, April 14 (HealthDay News) -- Older individuals with type 2 diabetes who have been hospitalized with severe low blood sugar levels seem to have a greater risk of developing dementia, new research suggests.

It's not yet clear whether less severe episodes of low blood sugar, which are more common, are also linked with an increased dementia risk, according to a study in the April 15 issue of the Journal of the American Medical Association, a themed issue on diabetes.

"Hypoglycemic episodes that were severe enough to require hospitalization or an emergency-room visit were associated with a greater risk of dementia, particularly for patients who had multiple episodes. And these findings, a little bit to our surprise, were independent of glycemic control," study author Rachel A. Whitmer, of Kaiser Permanente in Oakland, Calif., said during a Tuesday teleconference. "Episodes of hypoglycemia may be associated with neurological consequences in patients already at risk for dementia. This study seems to suggest that hypoglycemia is one of the reasons people with type 2 diabetes are at a higher risk for dementia. It also adds to the evidence base that balance of glycemic control is a critical issue, and particularly for the elderly."

People with type 2 diabetes are at a 32 percent greater risk for dementia, although the reasons for that are not clear. People with pre-diabetes are also at greater risk, Whitmer noted.

However, the study looks at association only, and doesn't actually prove any cause-and-effect link between the two conditions, cautioned Dr. Nir Barzilai, director of the Institute for Aging Research at Albert Einstein College of Medicine and the Montefiore Hospital Diabetes Clinic in New York City.

"It could be fluctuation of glucose. We know that hyperglycemia [high blood sugar] is also very toxic to the cells. All those things cannot be dissected on a study like this," he said.

Whitmer also noted that hypoglycemia is likely only one reason for the heightened risk of dementia in individuals with type 2 diabetes.