Cecily O'Connor
RedwoodAge.com

Individuals with type 2 diabetes are at higher risk of being diagnosed with dementia due to low blood sugar episodes that are serious enough to require a visit to the hospital, according to a new study.

Kaiser Permanente looked at the health records of 16,667 elderly patients in Northern California who suffer from type 2 diabetes. The researchers identified 1,465 patients in the group that were hospitalized or had an emergency room admittance at least once for hypoglycemia, or low blood sugar, from 1980 to 2002.

Compared to those with no hypoglycemic episodes, patients who had a hypoglycemic episode from midlife to late life had a 45 percent increased risk of being diagnosed with dementia. Those with two episodes had a 115 percent increased risk, while adults that required hospitalization three or more times had a 160 percent increased risk.

Dementia is characterized by loss of memory and other cognitive functions. Alzheimer's Disease is the most common type of dementia, accounting for up to 80 percent of cases, according to the Alzheimer's Association. The rate of Alzheimer's is expected to rise as the population ages. About 5.3 million people have Alzheimer's today, and by 2050, there will be nearly a million new cases per year.

"We know that the brain becomes more vulnerable with age, and we need a better understanding of how glycemic control can affect brain health over the long term," said Dr. Rachel Whitmer, a research scientist with the Kaiser Permanente Division of Research in Oakland, Calif. "This study adds to the evidence base that perhaps we should rethink the notion of very tight glycemic control for our elderly patients with diabetes mellitus."

Too Tight?
The Kaiser study, which appears in the Journal of the Medical Association, provides additional information on the debate about how tightly blood sugar should be controlled in patients with type 2 diabetes, researchers said.

Three separate trials have shown that tight glycemic control does not benefit all patients, and may cause harm to some, especially to patients with more longstanding diabetes, previous cardiovascular disease, and possibly to those with a history of severe hypoglycemia, said Dr. Joe Selby, co-author of the study and director of Kaiser's research division.

"Our findings suggest that pursuit of 'tight' glycemic control may be inadvisable in older patients with type 2 diabetes if required treatment is causing hypoglycemia," he said.

Recent recommendations from the American Heart Association and the American College of Cardiology have urged that treatment be individualized ,and that caution be exercised to prevent severe hypoglycemia. Their guidelines also emphasize the importance of blood pressure control, lipid or cholesterol control, smoking cessation, and use of aspirin, Selby said.