Baseline Characteristics of the 251 Prevalent DSP Cases and the 107 Prevalent Controls According to the 4-Year Incidence of DSP.

Data are means ± standard deviations or n (%). For comparisons between two groups, p values reported are χ2 test statistics for categorical variables and T-tests for continuous variables. For comparisons between three groups, p values reported are χ2 test statistics for categorical variables and ANOVA for continuous variables. Normal values for individual NCS are as follows. Sural amp≥7.2 µV for age ≤65 and ≥5.5 µV for age >65, sural CV≥40 m/s, peroneal amp≥5 µV for age ≤65 and ≥3 for age >65, peroneal CV≥40 m/s, peroneal F wave ≤59 ms for height ≥182.9 cm and ≤58 ms for height ≤182.9 cm, tibial amp≥10 µV, tibial CV≥40 m/s, tibial F wave ≤55 ms. *p-value for ANOVA between Prevalent Cases, Incident DSP Cases and Incident DSP Controls. †By subject self-report. ‡HbA1C, glycated hemoglobin A1C. §Summative parameters are composed of the following: sum amplitude = sural+tibial, sum conduction velocity = sural+peroneal +tibial, sum F-wave latency = peroneal+tibial. ¶Summed amplitude potentials are expressed in arbitrary units since sural amplitude potential is measured in microvolts and tibial amplitude potential is measured in millivolts. ∥Statistical tests for the NCS parameters applied a Bonferroni correction for multiple comparisons for significance such that p-values <0.0045 (0.05/11) were considered significant. All p-values except for two indicated by this symbol, met significance criteria. TCNS, Toronto Clinical Neuropathy Score. Amp, amplitude potential. CV, conduction velocity. F-wave, F-wave latency.