Table 2. Population studies for AE in rural China.
| Region | Number with AE | Population size studied | Reference |
| Ningxia (Xija, Guyuan and Haiyuan counties | 96 | 4778 | [51] |
| Sichuan (Ganzu autonomous prefecture) | 308 | 8512 | [52] |
| Gansu (Dingxi prefecture) | 114 | 3836 | [53] |
| Qinghai | 39 | 1549 | [54] |
| Sichuan | 60 | 705 | [55] |
| Gansu | 84 | 2482 | [56] |
| Gansu (Ming and Zhang counties) | 86 | 2485 | [57] |
| Qinghai (Zhiduo County) | 2 | 979 | [58] |
| Qinghai (Chindu, Zeko and Gade counties) | 31 | 3703 | [59] |
| Sichuan (Ganzi and Shiqu counties) | 223 | 7138 | [12] |
| Ningxia Hui Autonomous Region (Xiji County) | 20 | 221 | [60] |
| *Total | 1063 | 36388 | 2.9% |
| +Gansu (Zhang county) | 65 | 1312 | [6] |
*Total of studies in the last 10 years.
+Study from 1992.