Table 2.
Statistical data obtained by of the first and second multivariate quantile regression analyses (quantile regression analyses)
| Results of the first quantile regression analyses after forward stepwise analyses verifying dependency of Amp, CV, VT on demographic variables | ||||||
|---|---|---|---|---|---|---|
| Demographic variables | ||||||
| Sex (female) | Age | Height | Weight | Body mass index | ||
| Nerve function tests | Constant | Regression coefficient P‐value [95% CI] | Regression coefficient P‐value [95% CI] | Regression coefficient P‐value [95% CI] | Regression coefficient P‐value [95% CI] | Regression coefficient P‐value [95% CI] |
| Amp | 15.87 | – |
−0.095 <0.001 [−0.156, −0.038]* |
– | – |
−0.158 0.097 [−0.344, 0.028] |
| CV | 85.90 |
1.146 0.389 [−1.459, 3.751] |
−0.112 0.020 [−0.206, −0.017]* |
−0.224 0.007 [−0.390, −0.059]* |
0.064 0.244 [−0.044, 0.173] |
– |
| VT | −35.25 | – |
0.487 <0.001 [0.350, 0.625]* |
0.208 0.059 [0.050, 0.365] |
– | – |
| Results of the second quantile regression analysis and the regression formulas representing the cut‐off value of normal limit of nerve function tests | ||||||
|---|---|---|---|---|---|---|
| Age | Height | |||||
| Nerve function tests | Constant |
Regression coefficient P‐value [95% CI] |
Regression coefficient P‐value [95% CI] |
Regression formulas representing the normal limit | ||
| Amp | 12.62 |
−0.103 <0.001 [−0.162, −0.044]* |
Amp = 12.62 – 0.103 × age (years) | |||
| CV | 94.88 |
−0.148 0.016 [−0.269, −0.027]* |
−0.231 0.001 [−0.369, −0.092]* |
CV = 94.88 – 0.148 × age (years) – 0.231 × height (cm) | ||
| VT | 4.615 |
0.385 <0.001[0.224, 0.545]* |
VT = 4.615 + 0.385 × age (years) | |||
*Statistically significant values. –, Excluded by forward stepwise analyses; Amp, amplitude of action potential of sural nerve; CI, confidence interval; CV, conduction velocity of sural nerve; VT, vibratory perception threshold.