A joint Group Health-University of Washington (UW) study in the New England Journal of Medicine has found that higher blood sugar levels are associated with higher dementia risk, even among people who do not have diabetes. Blood sugar levels averaged over a five-year period were associated with rising risks for developing dementia, in this report about more than 2,000 Group Health patients age 65 and older in the Adult Changes in Thought (ACT) study.

For example, in people without diabetes, risk for dementia was 18 percent higher for people with an average glucose（葡萄糖） level of 115 milligrams per deciliter（分升） compared to those with an average glucose level of 100 mg/dl. And in people with diabetes, whose blood sugar levels are generally higher, dementia risk was 40 percent higher for people with an average glucose level of 190 mg/dl compared to those with an average glucose level of 160 mg/dl.

"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 first author Paul K. Crane, MD, MPH, an associate professor of medicine at the UW School of Medicine, adjunct associate professor of health services at the UW School of Public Health, and affiliate investigator at Group Health Research Institute. "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, a longitudinal cohort study, where we follow people for many years as they lead their lives," said senior author Eric B. Larson, MD, MPH, a senior investigator at Group Health Research Institute who also has appointments at the UW Schools of Medicine and Public Health. "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."

These measurements included blood glucose (some fasting, some not) and glycated hemoglobin (also known as HbA1c). Blood sugar levels rise and fall in peaks and valleys throughout each day, but glycated（糖化的） hemoglobin（血红蛋白） doesn't vary as much over short intervals. R. Walker, MS