| Sampling Location | 2012 | 2013 | ||||||
| Occupation(n) | Gender(n) | Age(n) | Occupation(n) | Gender(n) | Age(n) | |||
| Male | Female | Male | Female | |||||
| Lhasa | Farmers(29) | Farmers(29) | ||||||
| Teachers(5) | 23 | 28 | <30(43) | Teachers(1) | 14 | 19 | <30(23) | |
| Students(17) | 30~ < 40(26) | Students(3) | 30~ < 40(17) | |||||
| Shigatse | Farmers(36) | 14 | 22 | 40~ < 50(32) | Farmers(40) | 14 | 26 | 40~ < 50(33) |
| Tingri | Farmers(33) | 7 | 26 | 50~ < 60(26) | Farmers(15) | 8 | 7 | 50~ < 60(27) |
| Nagqu | Herdsmen(42) | 26 | 16 | ≥60(35) | Herdsmen(40) | 20 | 20 | ≥60(28) |