Table 1.
Distribution of BCRAT risk factors and breast cancer outcomes in the WHI
| Characteristic | Hispanic (n = 6,353) |
Non-Hispanic white (n = 128,976) |
P | ||
|---|---|---|---|---|---|
| BCRAT risk factorsa | |||||
| Age at baseline, years (mean [95% CI]) | 60.20 [60.04, 60.37] | 63.51 [63.47, 63.55] | <.001 | ||
| Age at menarche, years | N | % | N | % | |
| <12 | 1,560 | 24.8 | 27,718 | 21.6 | <.001 |
| 12–13 | 3,040 | 48.2 | 71,953 | 56.0 | |
| ≥14 | 1,701 | 27.0 | 28,848 | 22.4 | |
| Age at first live birth, years | |||||
| <20 | 1,087 | 17.6 | 14,603 | 11.5 | <.001 |
| 20–24 | 1,869 | 30.2 | 51,016 | 40.0 | |
| 25–29/Nulliparous | 2,773 | 44.9 | 52,436 | 41.1 | |
| ≥30 | 453 | 7.3 | 9,484 | 7.4 | |
| Number of first-degree relatives with breast cancer | |||||
| 0 | 5,318 | 89.9 | 103,979 | 85.1 | <.001 |
| 1 | 529 | 8.9 | 16,471 | 13.5 | |
| ≥2 | 71 | 1.2 | 1,696 | 1.4 | |
| Number of breast biopsies | |||||
| 0 | 4,909 | 83.2 | 95,075 | 78.9 | <.001 |
| 1 | 689 | 11.7 | 18,955 | 15.6 | |
| ≥2 | 304 | 5.1 | 7,949 | 6.5 | |
| OS Participants | 3,479 | 54.8 | 73,485 | 57.0 | <.001 |
| CT Participants | 2,874 | 45.2 | 55,491 | 43.0 | <.001 |
| HT | 1,536 | 53.4 | 22,006 | 39.7 | |
| Non-HT | 1,338 | 46.6 | 33,485 | 60.3 | |
| Breast cancer outcomes and follow-up time in WHI main study | |||||
| Number of Invasive breast cancers | 130 | 4,713 | |||
| Age at diagnosis, years (mean [95% CI]) | 63.8 [62.7, 65.0] | 68.3 [68.1, 68.5] | <.001 | ||
| Follow-up time, years (mean [95% CI]) | 7.57 [7.53, 7.62] | 8.12 [8.11, 8.13] | <.001 | ||
Note: CT clinical trial, OS observational study, HT hormone therapy trial, 95% CI 95% confidence interval. P value for differences among categorical variables are from χ2 test and for differences among continuous variables are from t test
a
Information on presence of atypical hyperplasia was not available in the WHI data