Higher blood-sugar levels - but not high enough to cause diabetes - may increase the risk of developing the memory-robbing disease dementia, a new major study of over 2,000 volunteers has found.
The study suggests a potential way to prevent Alzheimer's disease - by keeping glucose at a healthy level, researchers said.
Researchers found that blood sugar levels averaged over a five-year period were associated with rising risks for developing dementia, in the report about more than 2,000 Group Health patients aged 65 and older.
For example, in people without diabetes, risk for dementia was 18 per cent higher for people with an average glucose level of 115 milligrammes per decilitre 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 per cent 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, from the University of Washington.
"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.
"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," said Larson.
"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," Crane said.
The study was published in the New England Journal of Medicine.
