Characteristics of cohorts included in the study
| Country | Mine | Period of employment | Period of follow up | Sex | Workers (n) | Person-years |
| Italy | Abbadia | 1920–1983 | 1950–1994 | Men | 1059 | 38351 |
| Spain | Almaden | 1897–1994 | 1950–1994 | Men | 3648 | 103728 |
| Slovenia | Idrija | 1950–1990 | 1950–1995 | Men | 1589 | 49056 |
| Ukraine | Nikitovka | 1943–1990 | 1958–1990 | Men | 488 | 8622 |
| Total | Men | 6784 | 199757 | |||
| Ukraine | Nikitovka | 1943–1990 | 1958–1990 | Women | 265 | 5307 |