Table 1 Prevalence of radiological silicosis by age category and years since first employment in the mining industry, both reading sets
Reader I | Combined reading | ||||||||
|---|---|---|---|---|---|---|---|---|---|
ILO grade ≥1/0 | ILO grade ≥1/1 | ILO grade ≥1/0 | ILO grade ≥1/1 | ||||||
N | n | Prevalence % (95 % CI)a | n | Prevalence % (95 % CI)a | n | Prevalence % | n | Prevalence % | |
Total | 11,557 | 659 | 478 | ||||||
By age (years) | |||||||||
18–44 | 6468 | 128 | 2.0 (1.5, 2.7) | 85 | 1.3 (0.9, 1.8) | 56 | 0.9 | 98 | 1.5 |
45+ | 4994 | 526 | 10.5 (8.6, 12.9) | 389 | 7.8 (6.1, 10.0) | 659 | 13.2 | 551 | 11.0 |
Totalb | 11,462 | 654 | 5.7 (4.6, 7.1) | 474 | 4.1 (3.2, 5.3) | 715 | 6.2 | 649 | 5.7 |
By duration since first employment (years) | |||||||||
≤20 | 5456 | 81 | 1.5 (1.1, 2.1) | 52 | 1.0 (0.7, 14.0) | 27 | 0.5 | 48 | 0.9 |
21+ | 6020 | 573 | 9.5 (7.8, 11.7) | 423 | 7.0 (5.5, 9.0) | 681 | 11.3 | 618 | 10.3 |
Totalc | 11,476 | 654 | 5.7 (4.6, 7.1) | 475 | 4.1 (3.2, 5.3) | 708 | 6.2 | 666 | 5.8 |