Table 1.
Characteristics of the French nuclear worker cohort SELTINE, followed-up for mortality over period 1968–2014.
| Characteristics | Male | Female | Total | |||
|---|---|---|---|---|---|---|
| Number of workers | 69,487 | 10,861 | 80,348 | |||
| Number of person-years | 2,202,492 | 352,062 | 2,554,554 | |||
| Median year of birth (range) | 1951 (1893–1984) | 1947 (1896–1983) | 1951 (1893–1984) | |||
| Follow-up (1968–2014), in years (SD) | ||||||
| Mean duration | 31.7 | (11.4) | 32.4 | (13.0) | 31.8 | (11.6) |
| Mean age at beginning of follow-up | 31.1 | (8.1) | 31.0 | (8.8) | 31.1 | (8.2) |
| Mean age at end of follow-up | 62.8 | (13.6) | 63.4 | (15.3) | 62.9 | (13.9) |
| Vital status on 31 December 2014, n (%) | ||||||
| Alive | 55,134 | (79.3) | 9164 | (84.4) | 64,298 | (80.0) |
| Deceased | 14,131 | (20.4) | 1564 | (14.4) | 15,695 | (19.5) |
| Lost to follow-up | 222 | (0.3) | 133 | (1.2) | 355 | (0.5) |
| Employment | ||||||
| Median year of hiring (range) | 1977 | 1938–2004 | 1974 | 1940–2003 | 1977 | 1938–2004 |
| Mean age at hiring, in years (SD) | 26.4 | (6.3) | 26.1 | (7.0) | 26.3 | (6.4) |
| Mean duration, in years (SD) | 26.5 | (9.0) | 24.4 | (10.6) | 26.2 | (9.2) |
| Hired after 1956, n (%) | 66,003 | (95.0) | 10,239 | (94.3) | 76,242 | (94.9) |
| Number of person-years by principal * employing company (%) | ||||||
| CEA | 1,133,865 | (51.5) | 284,956 | (80.9) | 1,418,821 | (55.5) |
| Orano | 232,415 | (10.5) | 17,247 | (4.9) | 249,662 | (9.8) |
| EDF | 768,889 | (34.9) | 39,299 | (11.2) | 808,188 | (31.6) |
| Other ** | 67,323 | (3.1) | 10,560 | (3.0) | 77,883 | (3.1) |
| Socioeconomic status, n (%) | ||||||
| Managers and engineers | 13,466 | (19.4) | 2492 | (22.9) | 15,958 | (19.9) |
| Administrative employees | 2909 | (4.2) | 3952 | (36.4) | 6861 | (8.5) |
| Skilled workers | 40,537 | (58.3) | 3448 | (31.8) | 43,985 | (54.7) |
| Unskilled workers | 11,787 | (17.0) | 827 | (7.6) | 12,614 | (15.7) |
| Unknown | 788 | (1.1) | 142 | (1.3) | 930 | (1.2) |
| Monitoring of external radiation exposure, in years | ||||||
| Mean duration (SD) | 21.2 | (9.9) | 15.0 | (9.8) | 20.3 | (10.1) |
| Mean age at last monitoring (SD) | 50.0 | (9.7) | 43.7 | (11.5) | 49.2 | (10.2) |
| Number of exposed *** workers (%) | 49,995 | (71.9) | 4585 | (42.2) | 54,580 | (67.9) |
| Cumulative Hp(10) dose, in milliSieverts (SD) | ||||||
| Mean (SD), whole cohort | 17.7 | (39.7) | 3.1 | (13.7) | 15.7 | (37.5) |
| Median/IQR/maximum, whole cohort | 2.1/0.0–16.1/668.6 | 0.0/0.0–0.9/573.9 | 1.3/0.0–13.0/668.6 | |||
| Mean (SD), exposed *** workers only | 24.7 | (44.9) | 7.3 | (20.4) | 23.1 | (43.6) |
| Person-years by categories of 10-years lagged cumulative Hp(10) dose in milliSievert, n (%) | ||||||
| <2.5 | 1,487,620 | (67.6) | 308,589 | (87.7) | 1,796,209 | (70.3) |
| 2.5 –4.9 | 128,096 | (5.8) | 13,295 | (3.8) | 141,391 | (5.5) |
| 5.0 –9.9 | 135,109 | (6.1) | 10,724 | (3.0) | 145,833 | (5.7) |
| 10.0–19.9 | 142,935 | (6.5) | 9470 | (2.7) | 152,405 | (6.0) |
| 20.0–49.9 | 169,571 | (7.7) | 7281 | (2.0) | 176,852 | (6.9) |
| 50.0–99.9 | 85,740 | (3.9) | 1865 | (0.5) | 87,605 | (3.4) |
| 100.0–199.9 | 42,162 | (1.9) | 641 | (0.2) | 42,803 | (1.7) |
| ≥200.0 | 11,259 | (0.5) | 197 | (0.1) | 11,456 | (0.5) |
| Person-years by status of neutron exposure, n (%) | ||||||
| Not exposed | 2,159,095 | (98.0) | 349,872 | (99.4) | 2,508,967 | (98.2) |
| Potentially exposed | 43,397 | (2.0) | 2190 | (0.6) | 45,587 | (1.8) |
| Person-years by status of potential for internal contamination, n (%) | ||||||
| No | 2,127,408 | (96.6) | 340,711 | (96.8) | 2,468,119 | (96.6) |
| Low/medium potential | 63,372 | (2.9) | 8780 | (2.5) | 72,152 | (2.8) |
| High potential | 11,712 | (0.5) | 2571 | (0.7) | 14,283 | (0.6) |
SD: standard deviation; IQR: interquartile range; * company in which the employee was hired for the longest period of time and, in case of a tie, the company corresponding to the first hiring is retained; ** mainly from subsidiaries of Orano; *** with at least one positive recorded dose.