Researchers followed roughly 2100 people aged 65 and older who were free of dementia at baseline. Over a median follow-up of 6.8 years, patients had at least five measurements of glucose or glycated hemoglobin taken. About a quarter of patients developed dementia.
For all participants, the risk for dementia increased with increasing glucose readings. For patients without diabetes, an average glucose level of 115 mg/dL was associated with an 18% higher risk for dementia, compared with a level of 100 mg/dL. For those with diabetes, 190 mg/dL was associated with a 40% increased risk, relative to 160 mg/dL.