Higher levels of blood sugar are associated with higher risk of dementia, even with people who do not are not diabetics, a University of Washington – Group Health joint study reveals.
In people without diabetes, risk for dementia averaged over a five-year period was 18% more for people with average glucose level of 115 milligrams per deciliter. This is compared to those with an average glucose level of 100 mg/dl.
For the people in the study with diabetes, dementia risk was 40% higher for people with an average glucose level of 190 mg/dl compared to those with an average glucose level of 160 mg/dl.
No Threshold of Lowered Risk
“The most interesting finding was that every incrementally higher glucose level was associated with a higher risk of dementia in people who did not have diabetes,” said UW School of Medicine’s Paul K. Crane, MD. “There was no threshold value for lower glucose values where risk leveled off.”
One major strength of this research is that it is based on the ACT study (Adult Changes in Thought), a longitudinal cohort study, where we follow people for many years as they lead their lives,"
said senior author Eric B. Larson, MD, MPH.
“We combine information from people’s research visits every other year with data from their visits to Group Health providers whenever they receive care. And this gave us an average of 17 blood sugar measurements per person: very rich data."
Measurements collected included blood glucose, some fasting, some not, and glycated hemoglobin, also called HbA1c. Blood sugar levels rise and fall in cycles through the day, but glycated hemoglobin doesn’t vary as much over short intervals.
Sugar or No Sugar?
Should people try to eat less sugar, like foods with a lower glycemic index? Not necessarily, Dr. Crane explained:
“Your body turns your food into glucose, so your blood sugar levels depend not only on what you eat but also on your individual metabolism: how your body handles your food."
However he does suggest that taking walks couldn’t hurt. The ACT study has previously linked physical activity to later onset and reduced risk of dementia, including Alzheimer’s disease.
In addition, Dr. Crane highlighted that the results are from an observational study:
“What we found was that people with higher levels of glucose had a higher risk of dementia, on average, than did people with lower levels of glucose,” he said.
“While that is interesting and important, we have no data to suggest that people who make changes to lower their glucose improve their dementia risk. Those data would have to come from future studies with different study designs."
Paul K. Crane, Rod Walker, Rebecca A. Hubbard, Ge Li, David M. Nathan, Hui Zheng, Sebastien Haneuse, Suzanne Craft, Thomas J. Montine, Steven E. Kahn, Wayne McCormick, Susan M. McCurry, James D. Bowen, Eric B. Larson.
Glucose Levels and Risk of Dementia.
New England Journal of Medicine, 2013; 369 (6): 540 DOI: 10.1056/NEJMoa1215740