• Schram, Miranda
• Henry, Ronald
• Sep, Simone
• Biessels, Geert Jan
• Kallen, Carla J. H. Van Der
• Geijselaers, Stefan L. C.
• Van Boxtel, Martin
• Verhey, Frans
• Dagnelie, Pieter C.
• Stehouwer, Coen
• Kroon, Abraham
• Schaper, Nicolaas

Abstract

Aims: Type 2 diabetes, hyperinsulinemia, and insulin resistance are associated with cognitive impairment. Experimental studies indicate that insulin signaling in the brain is related to cognitive performance. Here we evaluated whether insulin-related variables contribute to the variance in cognitive performance among individuals with type 2 diabetes. Methods: A total of 806 individuals with type 2 diabetes (mean age 62 +/- 8 years, HbAlc 6.9 +/- 1.1%) completed a neuropsychological test battery. Insulin-related variables evaluated were: fasting plasma insulin, C-peptide, and the Homeostasis Model Assessment (HOMA2-IR; in individuals without insulin treatment; n = 641). The unadjusted coefficient of determination (R-2), obtained from multiple linear regression analyses, was used to estimate the proportion of variance in cognition explained by insulin-related variables. Results: Sex, age, and educational level together explained 18.0% (R-2) of the variance in memory function, 26.5% in information processing speed, and 22.8% in executive function and attention. Fasting insulin, C-peptide, or HOMA2-IR did not increase the explained variance (maximum Delta R-2 0.3%, P >= 0.14). Similar results were obtained when insulin-related variables were added to models that additionally included glycemic control, cardiovascular risk factors, and depression. Conclusions: Our results show that measures of peripheral insulin resistance are unrelated to cognitive performance among individuals with adequately controlled type 2 diabetes.

Topics

• impedance spectroscopy