The analysis included 197 participants, who were cognitively normal at the beginning, from the brain autopsy, and 53 participants, using carbon 11-labeled Pittsburg compound(C-PIB) to assess fibillary amylase B level, from imaging study. All 240 participants had at least 2 oral glucose tolerance tests (OGTT) during the study. To prevent bias from the results, researchers only used values from OGTT level at baseline or before 70 years old.
The results from autopsy group have shown that there was no significant association between Alzheimer’s disease and glucose level or insulin homeostasis. Furthermore, there was no significant difference in fasting glucose, fasting insulin, and fasting Homeostasis Mode Assessment (HOMA) between dementia and non-dementia participants.
The results from the imaging cohort group have also shown that there was no significant association between mean cortical C-PIB retention and glucose level, insulin, or insulin resistance.
In conclusion, the study "pretty definitively" suggests that long term glucose intolerance do not affect the pathology of Alzheimer’s disease. However, the limitation of this study is the exclusion of out-of-control diabetes patients.
Thambisetty M , Metter J, Yang A, et al. Glucose Intolerance, Insulin Resistance, and Pathological Features of Alzheimer Disease in the Baltimore Longitudinal Study of Aging. JAMA Neurol. 2013