April 11, 2018
High levels of blood sugar are associated with declines in thinking and memory skills, a new study reports. The higher the blood sugar levels, the greater the likelihood and degree of decline, the researchers found.
Blood sugar, or glucose, is essential for providing energy to cells throughout the body. But if levels become too high and uncontrolled, people are at increased risk of developing Type 2 diabetes. High blood sugar may also damage blood vessels throughout the body, including in the brain.
Numerous studies have found links between diabetes and an increased risk of Alzheimer’s disease and other forms of dementia. For the new study, Chinese researchers looked at 5,189 older men and women whose average age was 66. They tested their blood sugar levels using by measuring HBA1c, a substance that reflects average blood sugar levels over the previous two to three months.
They followed the patients for up to 10 years, recording glucose levels. Participants also got periodic tests of memory and thinking skills. The study was published in the journal Diabetologia.
There was no link between blood sugar levels and cognitive function at the start of the study. But the researchers found that those with the highest levels of blood sugar also tended to score worst on tests of memory and thinking skills. The association was seen even in those who did not have diabetes.
The researchers controlled for various factors that can also contribute to memory decline, including smoking, alcohol consumption, high cholesterol and depression. The link between high blood sugar and memory decline persisted.
Wuxiang Xie, a researcher at the Peking University Health Science Center and the lead author of the study, speculated that damage to tiny blood vessels from high glucose levels could be contributing in part to the declines in cognitive function.
Further research is needed to determine whether taking steps to control a rise in blood sugar can help to fend off Alzheimer’s disease. In the meantime, experts recommend a healthful diet and lots of physical activity to help keep the brain healthy and to ward off dementia.
By www.ALZinfo.org, The Alzheimer’s Information Site. Reviewed by Marc Flajolet, Ph.D., Fisher Center for Alzheimer’s Research Foundation at The Rockefeller University.
Source: Fanfan Zheng, Li Yan, Zhenchun Yang, et al: “HBA1c, Diabetes and Cognitive Decline: The English Longitudinal Study of Ageing.” Diabetologia, Feb. 2018.