| Authors | Longstanding of the diabetes (years) | |
| DN | NDN | |
| Our study: 34 patients (Dakar) | 15.32 | 7.42 |
| Y. Zajjari et al. Marocco [6] | 15.5 | 4.5 |
| Jianhui Zhou et al. (China) [7] | 7.3 | 2.1 |