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Diabetes may not be linked to Alzheimer's disease pathogenesis
Recent literature suggests a link between diabetes and the risk for cognitive decline or Alzheimer’s disease. However, in a new report, researchers from the Baltimore Longitudinal Study of Aging wrote that insulin resistance, measures of glucose and insulin homeostasis are not associated with Alzheimer’s disease pathology.
“Our study found no association between lifetime measures of glucose homeostasis and standard measures of Alzheimer’s disease pathology or cortical fibrillar [amyloid] beta-cell deposition measured with [Pittsburgh Compound B]. Similarly, we did not find an association between a clinical diagnosis of dementia and hyperglycemia or hyperinsulinemia,” Madhav Thambisetty, MD, PhD, of the National Institute on Aging in Baltimore, and colleagues wrote. “Our results concur with other studies that found no association between diabetes and Alzheimer’s disease pathology, and we extend these observations more broadly to hyperglycemia and insulin resistance.”
Madhav Thambisetty
Researchers categorized patients into two groups: 197 enrolled in the Baltimore Longitudinal Study of Aging with two or more oral glucose tolerance tests while alive and a brain autopsy at the time of death; 53 living patients who underwent two or more OGTTs and were administered imaging with carbon 11-labeled Pittsburgh Compound B PET.
Thambisetty and colleagues wrote that there were no significant associations between measures of brain Alzheimer’s disease pathology or Pittsburgh Compound B beta-amyloid load and glucose tolerance or insulin resistance in patients who demonstrated a mean of 6.4 OGTTs during a follow-up period of 22.1 years.
Furthermore, 30 patients with diabetes who were administered medications also displayed similar Alzheimer’s disease pathology compared with other patients enrolled in the study, researchers wrote.
Although some limitations are evident, the researchers said these data indicate insulin may have effects downstream of amyloid-beta deposition. Further studies are warranted to clarify these findings.
Disclosure: The researchers report no relevant financial disclosures.