Table 1 Comparison of characteristics between the follow-up and lost-to-follow up cohorts, 2013–2015*
Variables | Total | Follow-up | Lost-to-follow up | P |
|---|---|---|---|---|
N (%) | n (%) | n (%) | ||
Total | 34 076 | 22 119 | 11 957 |  |
Gender | ||||
 Male | 15 913 (46.7) | 10 385 (47.0) | 5528 (46.2) | 0.207 |
 Female | 18 163 (53.3) | 11 734 (53.0) | 6429 (53.8) | |
Age groups | ||||
 65–74 | 21 592 (63.4) | 14 452 (65.3) | 7140 (59.7) | < 0.001 |
  ≥ 75 | 12 484 (36.6) | 7667 (34.7) | 4817 (40.3) | |
Nationality | ||||
 Han | 29 554 (86.7) | 18 918 (85.5) | 10 636 (89.0) | < 0.001 |
 Others | 4507 (13.3) | 3198 (14.5) | 1309 (10.9) | |
 Unknown | 15(0.1) | 3 (0.0) | 12 (0.1) | |
Education | ||||
 Illiteracy | 12 016 (35.3) | 8645 (39.1) | 3371 (28.2) | < 0.001 |
 Primary to secondary | 17 168 (50.4) | 11 413 (51.6) | 5755 (48.1) | |
 High school and above | 3663 (10.7) | 1343 (6.1) | 2320 (19.4) | |
 Unknown | 1229 (3.6) | 718 (3.2) | 511 (4.3) | |
Marital status | ||||
 Married | 24 828 (72.9) | 15 970 (72.2) | 8858 (74.1) | 0.001 |
 Others# | 9244 (27.1) | 6147 (27.8) | 3097 (25.9) | |
 Unknown | 4 (0.0) | 2 (0.0) | 2 (0.0) | |
Residence | ||||
Local resident | 31 316 (91.9) | 21 487 (97.1) | 9829 (82.2) | < 0.001 |
Others | 2760 (8.1) | 632 (2.9) | 2128 (17.8) | |
Annual average income per person in the family (RMB) | ||||
  ≥ 10 000 | 16 506 (48.4) | 8748 (39.5) | 7758 (64.9) | < 0.001 |
 2300–9999 | 11 935 (35.0) | 9230 (41.7) | 2705 (22.6) | |
  < 2300 | 4010 (11.8) | 3058 (13.8) | 952 (8.0) | |
 Unknown | 1625 (4.8) | 1083 (5.0) | 543 (4.5) | |
Diabetes | ||||
 No | 31 690 (93.0) | 20 697 (93.6) | 10 993 (91.9) | < 0.001 |
 Yes | 2386 (7.0) | 1422 (6.4) | 964 (8.1) | |
Previously treated with TB | ||||
 No | 33 503 (98.3) | 20 530 (98.4) | 11 750 (98.3) | 0.367 |
 Yes | 573 (1.7) | 333 (1.6) | 207 (1.7) | |
Chronic bronchitis | ||||
 No | 32 346 (94.9) | 20 905 (94.5) | 11 441 (95.7) | < 0.001 |
 Yes | 1632 (4.8) | 1147 (5.2) | 485 (4.1) | |
 Unknown | 98 (0.3) | 67 (0.3) | 31 (0.3) | |
Pneumoconiosis | ||||
 No | 33 989 (99.7) | 22 052 (99.7) | 11 937 (99.8) | 0.002 |
 Yes | 77 (0.2) | 63 (0.3) | 14 (0.1) | |
 Unknown | 10 (0.0) | 4 (0.0) | 6 (0.1) | |
Cigarette smoker | ||||
 Non-smoker | 27 363 (80.3) | 17 544 (79.3) | 9819 (82.1) | < 0.001 |
 Ex/current smoker | 6707 (19.7) | 4571 (20.7) | 2136 (17.9) | |
 Unknown | 6 (0.0) | 4(0.0) | 2(0.0) | |
Alcohol drinker | ||||
 Non-drinker | 27 526 (80.9) | 17 604 (79.6) | 9922 (83.0) | < 0.001 |
 Ex/current drinker | 6501 (19.1) | 4499 (20.3) | 2002 (16.7) | |
 Unknown | 49 (0.1) | 16 (0.1) | 33 (0.3) | |
BMI level | ||||
 18.5–23.9 | 20 754 (60.9) | 13 680 (61.8) | 7074 (59.2) | < 0.001 |
  < 18.5 | 3585 (10.5) | 2477 (11.2) | 1108 (9.3) | |
  ≥ 24 | 9730 (28.6) | 5958 (26.9) | 3772 (31.5) | |
 Unknown | 7 (0.0) | 4 (0.0) | 3 (0.0) | |