Table 2.
Multivariable hazard ratios (HR) and 95% confidence intervals (CI) of breast cancer associated with the degree of a woman's affected relatives1
| Relative with breast cancer | Subjects | Person-Years | Cases | Adjusted2 HR (95%CI) |
|---|---|---|---|---|
| No family history (Ref.) | 44,421 | 127,114 | 558 | 1.0 |
| 1st degree family history | 14,675 | 44,553 | 314 | 1.54 (1.34-1.77) |
| 1st degree history only | 8,355 | 25,329 | 181 | 1.52 (1.28-1.80) |
| 1st and 2nd degree history | 6,320 | 19,224 | 133 | 1.58 (1.30-1.90) |
| Number of affected 1st degree relatives | ||||
| 1 | 12,392 | 37,328 | 252 | 1.51 (1.30-1.75) |
| 2+ | 1,947 | 6,215 | 56 | 1.76 (1.33-2.32) |
| Age of affected 1st degree relatives | ||||
| ≥50 years only | 8,501 | 25,791 | 184 | 1.56 (1.32-1.84) |
| At least one <50 years | 5,177 | 15,723 | 99 | 1.42 (1.15-1.76) |
| 2nd degree family history3 | ||||
| 2nd degree history only | 16,073 | 46,758 | 215 | 1.15 (0.98-1.35) |
| Number of affected 2nd degree relatives | ||||
| 1 | 10,793 | 31,387 | 158 | 1.25 (1.05-1.50) |
| 2+ | 5,280 | 15,370 | 57 | 0.94 (0.71-1.23) |
| Age of affected 2nd degree relatives | ||||
| ≥50 years only | 7,283 | 21,262 | 104 | 1.23 (0.99-1.51) |
| At least one <50 years | 6,184 | 17,764 | 75 | 1.06 (0.84-1.36) |
1
Estimated using Cox Proportional Hazards Models among women in the Group Health Breast Cancer Screening Program between June 1, 2001 and December 31, 2005
2
Adjusted for age at baseline (quadratic) and stratified by source of risk factor information
3
Among women with no affected 1st degree relatives