Regional differences in the breast cancer risk of BRCA1/2 carriers, excluding index cases (adjusted for birth year), in the Netherlands: The study population (Northern Netherlands) compared with the reference population (the rest of the Netherlands)
| Regional differences | ||||||
|---|---|---|---|---|---|---|
| BRCA1 | BRCA2 <60 | BRCA2 ≥60 | ||||
| Model | N (events) | HR (95% CI) | N (events) | HR (95% CI) | N (events) | HR (95% CI) |
| Region | ||||||
| Reference population | 1,091 (371) | 1 | 305 (91) | 1 | 29 (3) | 1 |
| Study population | 467 (141) | 0.66 (0.54–0.81) | 269 (59) | 0.64 (0.51–0.81) | 38 (11) | 3.99 (1.11–14.35) |
| Region | ||||||
| Reference population | 913 (281) | 1 | 224 (56) | 1 | 20 (3) | 1 |
| Study population | 467 (141) | 0.73 (0.59–0.89) | 269 (59) | 0.66 (0.46–0.96) | 38 (11) | 2.92 (0.81–10.55) |
| Regiona corrected for OCCR | ||||||
| Reference population | 913 (281) | 1 | 224 (56) | 1 | 20 (3) | 1 |
| Study population | 467 (141) | 0.75 (0.61–0.93) | 269 (59) | 0.50 (0.33–0.77) | 38 (11) | 2.61 (0.68–10.00) |
↵aIncluding only carriers with known mutation spectrum.