Table 1.
Characteristic of study subjects by examination status by ethnicity, age group, and sex, n (%)
| Population in study areas | People selected | People examined | Not available | Refused | Unable | |
| Ethnicity | ||||||
| Tibetan | 854 827 (78.3) | 4323 (86.5)* | 4127 (95.5) | 101 (2.34) | 46 (1.06) | 49 (1.13) |
| Han | 199 157 (18.2) | 523 (10.5)* | 495 (94.7) | 8 (1.53) | 5 (0.96) | 15 (2.87) |
| Other | 37 888 (3.47) | 154 (3.08) | 142 (92.2) | 0 (0.00) | 2 (1.30) | 10 (6.49)† |
| Total | 1 091 872 (100.0) | 5000 (100.0) | 4764 (95.3) | 109 (2.18) | 53 (1.06) | 74 (1.48) |
| Male | Female | Total | ||||
| Age | Population in study areas | People examined | Population in study areas | People examined | Population in study areas | People examined |
| 50–59 years | 44 718 (49.6) | 802 (38.4) | 41 013 (43.7) | 1029 (38.4) | 85 731 (46.6) | 1831 (38.4) |
| 60–69 years | 29 629 (32.9) | 730 (35.0) | 31 134 (33.2) | 852 (31.8) | 60 763 (33.0) | 1582 (33.2) |
| 70–79 years | 12 442 (13.8) | 429 (20.6) | 16 163 (17.2) | 609 (22.8) | 28 605 (15.5) | 1038 (21.8) |
| 80+ years | 3364 (3.73) | 126 (6.04) | 5551 (5.91) | 187 (6.99) | 8915 (4.84) | 313 (6.57) |
| Total | 90 153 (100.0) | 2087 (100.0) | 93 861 (100.0) | 2677 (100.0) | 184 014 (100.0) | 4764 (100.0) |
*More Tibetan and less Han Chinese selected compared their proportion of total population in study areas (p<0.001)
†Other ethnic minorities had higher proportion of ‘not available’.