Low serum magnesium levels are associated with impaired peripheral nerve function in type 2 diabetic patients

The aim of this study was to explore the relationship between serum magnesium and peripheral nerve function in patients with type 2 diabetes (T2DM). A total of 978 T2DM patients were included in the study. Patients were divided into tertiles according to serum magnesium concentration (low tertile: ≤0.85 mmol/L; medium tertile: 0.85 to 0.92 mmol/L; and high tertile: >0.92 mmol/L). All participants underwent nerve conduction (NC) studies. Composite z scores of conduction velocity, latency, and amplitude were constructed, respectively. The serum magnesium levels were significantly lower in patients with abnormal NC than in those with normal NC (0.87 [0.82, 0.92] vs. 0.88 [0.83, 0.93] mmol/L, P = 0.048). The composite z score of amplitude significantly increased with increasing tertiles of magnesium (-0.60 ± 0.02 vs. -0.57 ± 0.02 vs. -0.48 ± 0.03, P for trend = 0.001). After adjusting for all potential confounders, lower serum magnesium levels were still associated with lower composite z score of amplitude (β = 0.095, P = 0.014). In patients with T2DM, lower serum magnesium levels were significantly associated with lower composite z score of amplitude, indicating magnesium might affect peripheral nerve function through axonal degeneration.