Los Angeles—Could treating diabetes—whatever therapy is used—be protective against Alzheimer’s disease in patients with high blood sugar?

A study in the journal Diabetes Care suggests that might be the case, finding that patients with untreated diabetes developed signs of Alzheimer's disease 1.6 times faster than adults who did not have diabetes.

“Our findings emphasize the importance of catching diabetes or other metabolic diseases in adults as early as you can,” said coauthor Daniel A. Nation, a psychologist at the USC Dornsife College of Letters, Arts, and Sciences in a university press release. “Among people with diabetes, the difference in their rate of developing the signs of dementia and Alzheimer’s is clearly tied somehow to whether or not they are on medication for it.”

The study sought to investigate relationships among type 2 diabetes treatment, Alzheimer’s disease biomarkers, and risk for dementia. To do so, researchers performed lumbar puncture to determine cerebrospinal fluid (CSF) phosphorylated tau (p-tau), total tau (t-tau), and beta-amyloid 1-42 in 900 participants from the Alzheimer Disease Neuroimaging Initiative who were dementia-free at baseline and underwent health assessment, cognitive testing, and MRI.

The patients were grouped by fasting blood glucose level and medication history: euglycemia (EU), prediabetes (PD), untreated diabetes (UD), and treated diabetes (TD). Then the study team investigated any relationships among treatment status, CSF biomarkers, and risk for dementia.

Among the patients studied, 54 had type 2 diabetes but were not being treated, while 67 were receiving treatment. Most, 530 of 900, had normal blood sugar levels, and 250 had prediabetes.

Results indicated that the UD group displayed greater p-tau, t-tau, and p-tau/beta-amyloid 1-42 levels than the EU, PD, and TD groups (P values <.05) and higher t-tau/ beta-amyloid 1-42 than the EU and PD groups (P values <.05). In fact, researchers pointed out, the UD group progressed to dementia at higher rates than the EU group (hazard ratio 1.602 [95% CI 1.057-2.429]; P = .026).

“Treatment status may alter the relationship between type 2 diabetes and both Alzheimer disease biomarker profile and risk for dementia,” study authors concluded. “UD is associated with elevated tau pathology and risk for dementia, whereas TD is not. Although this study is observational and therefore causality cannot be inferred, findings support the potential importance of treatment status in Alzheimer disease risk associated with type 2 diabetes.”

Nation noted that the study is likely the first to compare the rate of developing the pathology for Alzheimer’s disease and dementia among people with normal glucose levels, with prediabetes, or people with type 2 diabetes—both treated and untreated.

“It is possible that the medicines for treating diabetes might make a difference in the progression of brain degeneration,” Nation emphasized. “But it’s unclear how exactly those medications might slow or prevent the onset of Alzheimer's disease, so that is something we need to investigate.”

 « Click here to return to Weekly News Update.