Study links dementia, low sugar in diabetics

McClatchy Newspapers

SACRAMENTO, Calif. — People with diabetes whose blood sugar plummets so low that they have to go to a hospital are likelier to get dementia later in life, a new study from Kaiser Permanente shows.

The Kaiser study analyzed the medical records of more than 16,000 diabetics throughout Northern California.

Those who went to an emergency room once or were hospitalized once for low blood sugar had at least a 29 percent greater chance of being diagnosed later with dementia. Those who had three hospital or emergency room visits were more than twice as likely to later develop dementia.

The study, published in Wednesday’s edition of the Journal of the American Medical Association, underscores the juggling act that diabetics and their doctors face in regulating blood sugar.

Last year, researchers stopped a major federal study in midstream when it turned out that intensive efforts to lower blood sugar to near normal levels led to more deaths for diabetics than controlling it a little less rigorously.

Blood sugar that rises too high can damage kidneys, eyes, blood vessels and the heart.

But blood sugar that sinks very low is also risky, because it can cause fainting, seizures or coma.

The Kaiser study suggests that severe bouts of low blood sugar, or hypoglycemia, might also subtly damage the brain in the long run, providing yet another reason to err on the side of slightly higher blood sugar for some diabetics.

“You have to exert some caution,” said Dr. Joe Selby, a co-author of the study and head of the research division for Kaiser Permanente in Northern California.

“The older you get, the more severe and prolonged your diabetes has been, the greater the chances you might experience hypoglycemia if you push” to rigorously limit blood sugar, Selby said.

People with diabetes do benefit if their hemoglobin A1c, a protein used to track blood sugar, can be lowered from 10 percent to 8 percent, but the benefits of trying to get down to 7 percent are much less clear cut for older patients, Selby said.