Characteristics of cognitive impairment and risk factors in type 2 diabetic mellitus patients

Abstract

Objective To investigate the characteristics of cognitive impairment in patients with type 2 diabetes mellitus (T2DM), and to analyze the correlation of T2DM with its risk factors and serum insulin-like growth factor-1 (IGF-1) levels Methods A total of 78 hospitalized patients with T2DM at our hospital from November 2011 to March 2012 were divided into the cognitive impairment group (n=39) and the non-cognitive impairment group (n=39) according to Montreal Cognitive Assessment (MoCA) scores, and general clinical data were collected. Levels of blood lipids, glycosylated hemoglobin (HbAlc), fasting blood glucose (FBG), fasting blood insulin (FBI) and other biochemical indicators were detected, insulin resistance index (HOMA-IR) scores were calculated, and serum IGF-1 levels were determined by the enzyme-linked immunosorbent assay (ELISA). Results The education levle was (8.94±4.13) years for the cognitive impairment group and (12.65±2.50) years for the non-cognitive impairment group, and there was a statistically significant difference between the two groups (P=0.004). HbAlc levels were (9.69±1.25) and (7.96±1.31) for the cognitive impairment group and the non-cognitive impairment group, respectively, and were statistically difference between the two groups (P=0.001). Serum IGF-1 levels were (122.60±11.56) mmol/L and (139.32±9.57) mmol/L in the cognitive impairment group and the non-cognitive impairment group, respectively, and had a statistically significant difference between the two groups (P=0.037). Additionally, compared with the non-cognitive impairment group, scores on visuospatial ability, naming, language, abstraction, delayed recall and orientation were lower in the cognitive impairment group (P<0.05 or 0.01). Moreover, MoCA scores were negatively correlated with TC, LDL-C, TG, HbAlc, FBI levels and HOMA-IR (r=-0.498, -0.411, -0.414, -0.452, -0.449, -0.539, respectively, P<0.05 for all), and positively correlated with education level and IGF-1 level (r=0.579 and 0.491, respectively, P<0.05 for both). Conclusions Cognitive impairment caused by T2DM is prominent in visuospatial ability, language, memory and executive functions, and is closely related to poor education, poor glycemic control, dyslipidemia and insulin resistance. Furthermore, decreased serum IGF-1 levels might be a risk factor for diabetic cognitive impairment. Key words: Diabetes mellitus, type 2; Cognition disorders; Insulin-like growth factor-1