USA: Study Highlights Association Between Diabetic Peripheral Neuropathy and Cognitive Performance

A recent study has highlighted the association between diabetic peripheral neuropathy (DPN) with lower cognitive performance in people with type 2 diabetes (T2D) of less than 10 years of known duration. DPN was found to be inversely and significantly associated with measures of immediate recall and processing speed. The study was published in the Journal of Diabetes and its Complications on 15 September 2021.

There is a lack of studies examining how measures of cognition are related to DPN presence and/or cardiovascular autonomic neuropathy (CAN). Also, data regarding factors potentially explaining such associations are lacking. To fill this knowledge gap, Joshua I. Barzilay, Emory University School of Medicine, Atlanta, GA, USA, and colleagues recruited participants from the Glycemia Reduction Approaches in Diabetes Study (GRADE) that examined 5047 middle-aged people with type 2 diabetes of less than 10 years of known duration.

Using the Spanish English Verbal Learning Test, the researchers assessed verbal learning and immediate and delayed recall (memory). Frontal executive function and processing speed were assessed with the Digit Symbol Substitution Test; ability to concentrate and organize data with word and animal fluency test. DPN was assessed with the Michigan Neuropathy Screening Instrument and CAN by indices of heart rate variability (standard deviation of normal beat to beat variation [SDNN] and root mean square of successive differences [RMSSD]).

Research Findings

• DPN was significantly inversely related to measures of immediate recall and processing speed.
• The percent of cognitive variation explained by DPN was small.
• Tests of CAN had an inconsistent or absent association with measures of cognition.
• Higher waist circumference and urine albumin creatinine (UACR) levels were the strongest correlates in the relationship between DPN and cognitive impairment.

"Our findings revealed that DPN, but not CAN, was cross-sectionally associated with lower performance in measures of cognition in people with type 2 diabetes of less than 10 years of known duration," wrote the authors. "Greater waist circumference and UACR were important variables in this association."

"Further study is warranted to evaluate the mechanism underlying the association between diabetic peripheral neuropathy and cognition," they concluded.

Reference

The study titled, "The cross-sectional association of cognition with diabetic peripheral and autonomic neuropathy—The GRADE study," was published in the Journal of Diabetes and its Complications.

DOI: https://www.sciencedirect.com/science/article/abs/pii/S1056872721002610