The relationship between type 2 diabetes mellitus with cognitive functions

BACKGROUND: Type 2 diabetes mellitus (T2DM) has been associated with impairment of cognitive functions. Since the majority of patients with diabetes in the Saudi population are between the ages of 40 and 69 years, it is crucial to ascertain whether the control of blood glucose level negatively correlates with the level of cognitive function scores similar to the way it correlates in those who are not controlling their blood glucose level with medications. AIMS: To assess cognitive functions in patients with T2DM and examine the effect of glycemic control on cognitive functions impairment in Saudi adults with T2DM. METHODS AND MATERIAL: Seventy-nine patients with T2DM underwent cognitive assessment testing using the Cambridge neuropsychological test automated battery (CANTAB), Mini-Mental State Examination (MMSE), and Fatigue severity scale. Their cognitive function scores were then correlated with their blood glucose levels, duration of diabetes, and levels of education. Poor glycemic control was defined as glycated hemoglobin levels more than 7.5. We excluded patients with depression or neurocognitive disorders as well as those over 75 years of age. RESULTS: Attention switching task (AST) total latency (P = 0.003), AST congruent score (P = 0.002), AST incongruent score (P = 0.003), AST block 3 (p = 0.004), and AST Block 7 (p = 0.006) were significantly higher in poorly-controlled DM. The intra-extra dimensional set shift (IED) total errors were significantly higher in poorly-controlled patients (p = 0.023). The difference in IED stages completed (p = 0.716) and spatial span (SSP) (p = 0.782) were not significant between the two groups. The mini-mental state exam (p = 0.336) and the fatigue severity scale (P = 0.167) did not show any statistical significance between good and poor control of T2DM. There was a significant positive correlation between the duration of T2DM and AST latencies for AST total latency, AST congruent score, and AST incongruent score. CONCLUSIONS: Patients with T2DM have a statistically significant association between their cognitive functions and their glycemic control. Patients with uncontrolled T2DM showed decreased cognitive scores. Moreover, worsened cognitive scores were associated with longer disease duration.