Controlling Blood Sugar Doesnt Improve Memory in Diabetics

WINSTON-SALEM, N.C.Intensive control of blood sugar levels beyond standard targets offers no additional protection against cognitive decline in older people with diabetes than standard treatment, according to a new study published in The Lancet Neurology.

Researchers at Wake Forest Baptist Medical Center coordinated the Action to Control Cardiovascular Risk in Diabetes-Memory in Diabetes (ACCORD-MIND) national study to examine the effects of different glucose-lowering strategies on the risk for cardiovascular disease.

"We know that people with type 2 diabetes have a much higher risk of dementia and memory loss than people without diabetes," said Jeff D. Williamson, M.D., chief of the Department of Geriatrics and Gerontology and principal investigator of the study's coordinating center at Wake Forest Baptist. "What we didn't know was, if you intensively control blood sugar levels in people who have had a history of trouble controlling them, does the added cost and effort to control blood sugar result in a slowed rate of memory loss? After conducting this study, there remains no evidence that it does.

To determine whether intensive blood glucose control would improve cognitive outcomes, the research team recruited nearly 3,000 people with long-standing type 2 diabetes and a high risk for heart disease for the study. Each was assigned either to an "intensive" program to maintain their hemoglobin A1c lower than standard targets at below 6%, or to a "standard" program to maintain the levels between 7% and 7.9%. Hemoglobin A1c is a marker for control of blood glucose levels. The patients ranged in age from 55 to 80 years old. All participants underwent cognitive testing and more than 600 people also received magnetic resonance imaging (MRI) scans to measure any change in brain volume during the study.

The initial study plan was to measure the participants' cognitive ability (through cognitive tests) and brain volume (through MRI) after 40 months, but an increased risk of dying in the intensive strategy group led the researchers to switch all the participants to the standard glucose-lowering strategy at a median treatment time of 39 months.

Cognitive test scores revealed no difference between the groups. People in the intensive treatment group had larger total brain volume. However, the result, when weighed against the lack of cognitive benefit, the increased risks of cardiovascular problems and increased mortality in the intensive treatment group, did not support use of the more intensive therapy, the researchers concluded.

"While these findings do not support the use of intensive therapy to reduce the possible effects of diabetes on the brains of older people, it remains important for older adults with type 2 diabetes to continue well-established regimens to keep their blood glucose levels under control," said lead author Lenore J. Launer, Ph.D., of the National Institute on Aging (NIA). "Cognitive health is of particular concern in type 2 diabetes. We will continue to investigate how managing blood sugar levels might be employed to protect people with diabetes from increased risk of cognitive decline as they age."