In a study recently published in Diabetes Care, C. Christine Lee, PhD, of the University of Toronto, and colleagues reported that prediabetes was associated with similar risks for peripheral neuropathy and severity of nerve dysfunction as new-onset diabetes. They also found an independent association between prediabetes and both peripheral neuropathy and severity of nerve dysfunction.2
While the exact mechanisms behind these associations are unclear, a growing body of evidence suggests that peripheral neuropathy begins in the early stages of diabetes pathogenesis, the researchers noted.
To study this further, they also examined the prevalence of peripheral neuropathy and nerve dysfunction according to glucose tolerance and metabolic syndrome status as well as how these conditions are associated with neurological changes in adults at risk for type 2 diabetes.
Lee and colleagues analyzed data on 467 individuals from the longitudinal PROMISE (Prospective Metabolism and Islet Cell Evaluation) study. The researchers found that the prevalence of peripheral neuropathy was 29% in adults with normal glycemia, as compared with 49% in adults with prediabetes and 50% in adults with new-onset diabetes.
For the study, the researchers defined peripheral neuropathy using the Michigan Neuropathy Screening Instrument (MNSI) scores (>2). They then measured the severity of nerve dysfunction objectively by vibration perception thresholds (VPTs) using a neurothesiometer.
Results revealed that the mean VPT was 6.5 V for individuals with normal glycemia and 7.9 V for individuals with prediabetes. For those with new-onset diabetes, the mean VPT was 7.6 V.
Additionally, after adjustment for known risk factors, prediabetes was associated with higher MNSI scores compared with normal glycemia. The researchers also found that progression of glucose intolerance over 3 years predicted a higher risk for peripheral neuropathy and nerve dysfunction.
Interestingly, metabolic syndrome was not independently associated with MNSI scores or VPTs, the researchers said.