Higher glucose levels associated with dementia even in non-diabetic patients

Higher glucose levels may be a risk factor for dementia among patients with and without diabetes, a study found.

To examine the relationship between glucose levels and dementia, researchers used 35,264 measurements of glucose levels and 10,208 measurements of glycated hemoglobin levels from 2,067 participants without dementia at a single health care system in the state of Washington, as part of the Adult Changes in Thought study.

In the study, 232 people with diabetes and 1,835 without it were randomly chosen, and their measurements were stratified by diabetes status, and then adjusted for age, sex, study cohort, educational level, level of exercise, blood pressure, coronary and cerebrovascular diseases, atrial fibrillation, smoking, and treatment for hypertension. Researchers assessed dementia every two years through the Cognitive Abilities Screening Instrument, which ranges from 0 to 100 (higher scores show better cognitive functioning). Results were published Aug. 8 in the New England Journal of Medicine.

Dementia developed in 524 participants (25.4%): 74 had diabetes (21.6% of all diabetics) and 450 (26.1% of non-diabetics) didn't. Among patients who didn't have diabetes, higher average glucose levels in the past five years were associated with an increased risk of dementia (P=0.01); for example, an average glucose level of 115 mg/dL was associated with a hazard ratio (HR) for dementia of 1.18 compared to 100 mg/dL (95% CI, 1.04 to 1.33). Among diabetics, higher average glucose levels were also related to higher risk of dementia: HR 1.40 for average glucose of 190 mg/dL compared to 160 mg/dL (95% CI, 1.12 to 1.76; P=0.002).

Researchers noted that their research implies that any incremental increase in glucose levels may be associated with an increased risk of dementia. They wrote, “These data suggest that higher levels of glucose may have deleterious effects on the aging brain. Our findings underscore the potential consequences of temporal trends in obesity and diabetes and suggest the need for interventions that reduce glucose levels.”