Table 3.
Number of cancer cases, crude and adjusted relative cancer risks in the Estonian cohort of Chernobyl cleanup workers by cancer site and selected characteristics, 1986–2008.
| Cancer site/ Characteristic | No. of cases |
Crude RRa |
95% CI | No. of cases |
Adjusted RRb |
95% CI | No. of cases |
Adjusted RRc |
95% CI |
|---|---|---|---|---|---|---|---|---|---|
| All sites | |||||||||
| Year of arrival in the Chernobyl area | |||||||||
| 1986 | 137 | 1.00 | 0.76–1.30 | 137 | 1.02 | 0.78–1.34 | 137 | 1.01 | 0.77–1.33 |
| 1987–1991 | 92 | 1 | 92 | 1 | 92 | 1 | |||
| Duration of stay in the Chernobyl area (days) | |||||||||
| <92 | 118 | 1 | 118 | 1 | 118 | 1 | |||
| ≥92 | 111 | 1.02 | 0.79–1.33 | 111 | 1.02 | 0.78–1.33 | 111 | 1.03 | 0.79–1.34 |
| Time since return from the Chernobyl area (years) | |||||||||
| <7 | 30 | 1 | 30 | 1 | 30 | 1 | |||
| 7–13 | 66 | 1.11 | 0.72–1.71 | 66 | 1.10 | 0.72–1.70 | 66 | 1.07 | 0.70–1.65 |
| ≥14 | 133 | 1.02 | 0.68–1.51 | 133 | 1.01 | 0.68–1.51 | 133 | 0.99 | 0.66–1.47 |
| Ethnicity | |||||||||
| Estonian | 123 | 1 | 123 | 1 | |||||
| Non-Estonian | 106 | 1.04 | 0.80–1.35 | 106 | 1.10 | 0.84–1.43 | |||
| Education | |||||||||
| Higher or secondary | 129 | 1 | 129 | 1 | |||||
| Basic or less | 100 | 1.54 | 1.19–2.00 | 100 | 1.57 | 1.20–2.06 | |||
|
| |||||||||
| Radiation-related sites | |||||||||
| Year of arrival in the Chernobyl area | |||||||||
| 1986 | 80 | 1.02 | 0.72–1.44 | 80 | 1.06 | 0.75–1.52 | 80 | 1.05 | 0.74–1.49 |
| 1987–1991 | 53 | 1 | 53 | 1 | 53 | 1 | |||
| Duration of stay in the Chernobyl area (days) | |||||||||
| <92 | 69 | 1 | 69 | 1 | 69 | 1 | |||
| ≥92 | 64 | 1.01 | 0.72–1.42 | 64 | 1.01 | 0.71–1.42 | 64 | 1.00 | 0.71–1.42 |
| Time since return from the Chernobyl area (years) | |||||||||
| <7 | 17 | 1 | 17 | 1 | 17 | 1 | |||
| 7–13 | 40 | 1.14 | 0.65–2.02 | 40 | 1.14 | 0.65–2.01 | 40 | 1.11 | 0.63–1.96 |
| ≥14 | 76 | 1.06 | 0.63–1.79 | 76 | 1.07 | 0.63–1.81 | 76 | 1.04 | 0.61–1.77 |
| Ethnicity | |||||||||
| Estonian | 67 | 1 | 67 | 1 | |||||
| Non-Estonian | 66 | 1.19 | 0.84–1.67 | 66 | 1.22 | 0.86–1.72 | |||
| Education | |||||||||
| Higher or secondary | 80 | 1 | 80 | 1 | |||||
| Basic or less | 53 | 1.31 | 0.93–1.85 | 53 | 1.32 | 0.92–1.90 | |||
|
| |||||||||
| Alcohol-related sites | |||||||||
| Year of arrival in the Chernobyl area | |||||||||
| 1986 | 40 | 1.06 | 0.65–1.73 | 40 | 1.00 | 0.60–1.66 | 40 | 1.00 | 0.60–1.64 |
| 1987–1991 | 26 | 1 | 26 | 1 | 26 | 1 | |||
| Duration of stay in the Chernobyl area (days) | |||||||||
| <92 | 32 | 1 | 32 | 1 | 32 | 1 | |||
| ≥92 | 34 | 1.15 | 0.71–1.86 | 34 | 1.13 | 0.69–1.84 | 33 | 1.13 | 0.69–1.85 |
| Time since return from the Chernobyl area (years) | |||||||||
| <7 | 7 | 1 | 7 | 1 | 7 | 1 | |||
| 7–13 | 13 | 0.87 | 0.35–2.18 | 13 | 0.85 | 0.34–2.14 | 13 | 0.83 | 0.33–2.09 |
| ≥14 | 46 | 1.58 | 0.71–3.51 | 46 | 1.53 | 0.69–3.41 | 46 | 1.52 | 0.68–3.38 |
| Ethnicity | |||||||||
| Estonian | 35 | 1 | 35 | 1 | |||||
| Non-Estonian | 31 | 1.06 | 0.65–1.72 | 31 | 1.18 | 0.72–1.94 | |||
| Education | |||||||||
| Higher or secondary | 33 | 1 | 33 | 1 | |||||
| Basic or less | 33 | 1.92 | 1.19–3.11 | 33 | 2.18 | 1.32–3.62 | |||
For year of arrival, duration of stay, and time since return from the Chernobyl area 167 subjects with unknown values were excluded; for ethnicity and education 556 subjects with unknown values were excluded.
Model 1: includes age at start of follow-up, year of arrival, duration of stay, and time since return from the Chernobyl area (167 subjects with unknown values were excluded).
Model 2: includes age at start of follow-up, year of arrival, duration of stay, time since return from the Chernobyl area, ethnicity and education (556 subjects with unknown values were excluded).