Description of the study population by subcohorts and date of birth
| Date of birth | Subcohort A (Hired 1946–1954) | Subcohort B (Hired 1955–1970) | Subcohort C (Hired since 1971) | Total | |||||
| Cases | Controls | Cases | Controls | Cases | Controls | Cases | Controls | ||
| Before 08.05.1929 | Subjects (n) | 152 | 453 | 28 | 84 | 2 | 5 | 182 | 542 |
| Mean date of birth | 04.02.1920 | 12.02.1920 | 05.12.1917 | 30.01.1918 | 17.09.1926 | 07.07.1926 | 01.11.1919 | 11.11.1919 | |
| Mean age at hire (years) | 29.4 | 29.7 | 39.4 | 40.0 | 48.6 | 47.4 | 31.1 | 31.4 | |
| Mean index date | 14.12.1974 | 02.02.1975 | 25.01.1975 | 03.04.1975 | 11.03.1983 | 16.09.1983 | 23.01.1975 | 13.03.1975 | |
| Mean age (years) | 54.9 | 55.0 | 57.1 | 57.2 | 56.6 | 57.2 | 55.2 | 55.3 | |
| Mean time since hire (years) | 25.5 | 25.3 | 17.8 | 17.2 | 8.0 | 9.9 | 24.1 | 23.9 | |
| Mean RQ exposure (mg/m³-years) | 14.63 | 14.92 | 4.67 | 4.54 | 0.10 | 0.16 | 12.94 | 13.18 | |
| Silicosis, n (%) | 23 (15.1) | 50 (11.0) | 1 (3.6) | 1 (1.2) | 0 (0.0) | 0 (0.0) | 24 (13.2) | 51 (9.4) | |
| Average latency to silicosis (years) | 15.7 | 16.6 | 12.2 | 1.6 | - | - | 15.6 | 16.3 | |
| Pre-exposure to RQ*, n (%) | 9 (5.9) | 15 (3.3) | 3 (10.7) | 4 (4.8) | 0 (0.0) | 0 (0.0) | 12 (6.6) | 19 (3.5) | |
| Former coalmining*, n (%) | 31 (20.4) | 84 (18.5) | 5 (17.9) | 15 (17.9) | 1 (50.0) | 1 (20.0) | 37 (20.3) | 100 (18.5) | |
| After 08.05.1929 | Subjects (n) | 50 | 150 | 50 | 151 | 10 | 29 | 110 | 330 |
| Mean date of birth | 28.10.1931 | 26.10.1931 | 18.03.1937 | 27.03.1937 | 14.03.1942 | 22.05.1942 | 20.03.1935 | 24.03.1935 | |
| Mean age at hire (years) | 18.6 | 19.1 | 22.7 | 22.7 | 35.4 | 33.3 | 22.0 | 22.0 | |
| Mean index date | 22.06.1981 | 09.07.1981 | 08.05.1984 | 22.05.1984 | 24.11.1984 | 27.01.1985 | 03.02.1983 | 22.02.1983 | |
| Mean age (years) | 49.7 | 49.7 | 47.1 | 47.2 | 42.7 | 42.7 | 47.9 | 47.9 | |
| Mean time since hire (years) | 31.1 | 30.6 | 24.5 | 24.5 | 7.3 | 9.4 | 25.9 | 26.0 | |
| Mean RQ exposure (mg/m³-years) | 16.35 | 14.19 | 3.65 | 4.23 | 0.32 | 0.42 | 9.12 | 8.42 | |
| Silicosis, n (%) | 5 (10.0) | 12 (8.0) | 0 (0.0) | 1 (0.7) | 0 (0.0) | 0 (0.0) | 5 (4.5) | 13 (3.9) | |
| Average latency to silicosis (years) | 15.5 | 20.1 | – | 13.9 | – | – | 15.5 | 19.7 | |
| Pre-exposure to RQ*, n (%) | 2 (4.0) | 7 (4.7) | 3 (6.0) | 6 (4.0) | 0 (0.0) | 2 (6.9) | 5 (4.5) | 15 (4.5) | |
| Former coalmining*, n (%) | 5 (10.0) | 17 (11.3) | 7 (14.0) | 16 (10.6) | 0 (0.0) | 4 (13.8) | 12 (10.9) | 37 (11.2) | |
| Total | Subjects (n) | 202 | 603 | 78 | 235 | 12 | 34 | 292 | 872 |
| Mean date of birth | 31.12.1922 | 10.01.1923 | 16.04.1930 | 22.05.1930 | 14.08.1939 | 20.01.1940 | 17.08.1925 | 03.09.1925 | |
| Mean age at hire (years) | 26.7 | 27.0 | 28.7 | 28.9 | 37.6 | 35.4 | 27.7 | 27.9 | |
| Mean index date | 25.07.1976 | 09.09.1976 | 06.01.1981 | 14.02.1981 | 17.08.1984 | 15.11.1984 | 01.02.1978 | 16.03.1978 | |
| Mean age (years) | 53.6 | 53.7 | 50.7 | 50.7 | 45.0 | 44.8 | 52.5 | 52.5 | |
| Mean time since hire (years) | 26.9 | 26.6 | 22.1 | 21.9 | 7.4 | 9.5 | 24.8 | 24.7 | |
| Mean RQ exposure (mg/m³-years) | 15.06 | 14.74 | 4.02 | 4.34 | 0.28 | 0.38 | 11.50 | 11.38 | |
| Silicosis, n (%) | 28 (13.9) | 62 (10.3) | 1 (1.3) | 2 (0.9) | 0 (0.0) | 0 (0.0) | 29 (9.9) | 64 (7.3) | |
| Average latency to silicosis (years) | 15.7 | 17.2 | 12.2 | 7.7 | – | – | 15.6 | 17.0 | |
| Pre-exposure to RQ*, n (%) | 11 (5.4) | 22 (3.6) | 6 (7.7) | 10 (4.3) | 0 (0.0) | 2 (5.9) | 17 (5.8) | 34 (3.9) | |
| Former coalmining*, n (%) | 36 (17.8) | 101 (16.7) | 12 (15.4) | 31 (13.2) | 1 (8.3) | 5 (14.7) | 49 (16.8) | 137 (15.7) | |
*Based on qualitative information from records of preventive medical examinations.
RQ, respirable quartz.