Table 2. Breast cancer incidence rates and relative risks by times of tumour diagnosis in the Techa River Incidence female cohort.
| Follow-up period | Number of cases | Number of person-years | Mean age, years | Crude rate per 105 PYR (95% CI) | RRa (95% CI) |
|---|---|---|---|---|---|
| 1956–1969 | 13 | 108300 | 39.4 | 12.0 (7.0–20.7) | 1.0 |
| 1970–1979 | 14 | 61056 | 48.9 | 22.9 (13.6–38.7) | 1.3 (0.6–2.9) |
| 1980–1989 | 30 | 48847 | 55.7 | 61.4 (42.9–87.8) | 2.86 (1.5–5.5) |
| 1990–2004 | 52 | 52086 | 63.5 | 99.8 (76.17–131.0) | 3.9 (2.1–7.7) |
| 1956–2004 | 109 | 270289 | 49.1 | 40.3 (33.4–48.7) |
a
Relative risk adjusted for age at diagnosis, ethnicity, number of children, time of arrival on the contaminated territory (before and after 1953) and 5-year lagged cumulative stomach dose based on linear ERR model.