Variable Name | Possible values and number of examples | |||
---|---|---|---|---|
 | Category | With CWP (n = 236) | Without CWP (n = 14419) | χ2(P) |
Birth (year of birthday) | (7)Before 1930 | 52 | 201 | 1821.977 (<0.0001) |
 | (6)1930- | 129 | 696 |  |
 | (5)1940- | 40 | 871 |  |
 | (4)1950- | 14 | 3652 |  |
 | (3)1960- | 1 | 6168 |  |
 | (2)1970- | 0 | 2736 |  |
 | (1)After 1980 | 0 | 95 |  |
Age (age in years of first exposure to dust) | (7)< 20 | 60 | 6328 | 60.003 (<0.0001) |
 | (6)20- | 100 | 5786 |  |
 | (5)25- | 51 | 1614 |  |
 | (4)30- | 16 | 454 |  |
 | (3)35- | 8 | 167 |  |
 | (2)40- | 1 | 61 |  |
 | (1)≥45 | 0 | 9 |  |
Year (year of first exposure to dust) | (7)Before 1950 | 14 | 33 | 1992.257 (<0.0001) |
 | (6)1950- | 149 | 669 |  |
 | (5)1960- | 57 | 759 |  |
 | (4)1970- | 15 | 3026 |  |
 | (3)1980- | 1 | 6164 |  |
 | (2)1990- | 0 | 3764 |  |
 | (1)After 2000 | 0 | 4 |  |
Job (occupational category) | (4)Tunneling | 201 | 4949 | 274.335 (<0.0001) |
 | (3)Combining | 9 | 670 |  |
 | (2)Mining | 23 | 2892 |  |
 | (1)Helping | 3 | 5908 |  |
Time 1(years) | Duration of dust exposure | 23.38 ± 7.07 | 18.31 ± 7.05 | 120.561 (<0.001) |
Time 2(years) | Duration of ex-dust exposure | 6.09 ± 7.96 | 2.49 ± 5.72 | 47.613 (<0.001) |