Possible association between mild cognitive impairment and prediabetes: A Case-Control Study

Background: Prediabetes is an intermediate stage of dysglycemia, diagnosed by fasting blood glucose (FBG), glycosylated hemoglobin (HbA1c), or 2-h post-load glucose (2hBG). It is a significant risk factor for progression to type 2 diabetes (T2D). While T2D is strongly associated with cognitive decline, the relationship between prediabetes and mild cognitive impairment (MCI) remains uncertain. MCI represents a transitional phase toward dementia. Aim: To investigate the possible association between prediabetes and mild cognitive impairment. Subjects and methods: This case-control study was conducted on 100 patients from August 2024 to March 2025 in outpatient and inpatient internal medicine and neurology clinics at Al-Azhar University hospitals in Cairo. Results: Both HbA1c and IFG were markedly elevated in the prediabetes group (6.02±0.22% and 6.50±0.25 mmol/dL, respectively) compared to controls (5.07±0.36% and 5.48±0.32 mmol/dL), with p-values <0.001, confirming the metabolic distinction. The QMCI percentage was substantially lower in the case group (54.38±3.41%) than in the control group (79.38±11.22%), and the MoCA score was also reduced in the case group (21.90±2.59 vs. 27.88±1.44; p<0.001 for both), indicating a clear association between prediabetes and cognitive decline. Conclusion: The significant reduction in cognitive performance scores and prolonged P300 latencies among prediabetic individuals underscores the subtle yet impactful neurocognitive consequences of early metabolic dysregulation. Furthermore, logistic regression analyses identified P300 latency, particularly at the Fz and Pz electrodes, as independent predictors of prediabetes status, reinforcing their potential utility as early biomarkers.