“We found a steadily increasing risk associated with ever-higher blood glucose levels, even in people who didn’t have diabetes. There’s no threshold, no place where the risk doesn’t go up any further or down any further.” The association with dementia kept climbing with higher blood sugar levels and, at the other end of the spectrum, continued to decrease with lower levels.
This held true even at glucose levels considered normal. Among those whose blood sugar averaged 115 milligrams per deciliter, the risk of dementia was 18 percent higher than among those at 100 mg/dL, just slightly lower. The effects were also pronounced among those with diabetes: patients with average glucose levels of 190 mg/dL had a 40 percent higher risk of dementia than those whose levels averaged 160 mg/dL.