Table 3.
Hazard of invasive breast cancer according to each component cause, adjusting for potential confounders, in postmenopausal women (50-79 years old) enrolled in the Women's Health Initiative Observational Study (1993-2003)
| Component one | Component two | |
|---|---|---|
| FHLBC | Breast healthy behavior | |
| Crude HR (95% CI) | Crude HR (95% CI) | |
| 1.50 (1.33, 1.68) | 0.76 (0.60, 0.97) | |
| Potential confounders | Adjusted HR (95% CI) | Adjusted HR (95% CI) |
| Age | 1.48 (1.31, 1.66) | 0.77 (0.61, 0.99) |
| Education | N/A | 0.75 (0.59, 0.95) |
| Caucasian | 1.47 (1.30, 1.65) | 0.77 (0.61, 0.97) |
| Income of less than $35,000/year | N/A | 0.77 (0.60, 0.98) |
| No mammogram in past 2 years | 1.48 (1.31, 1.67) | 0.74 (0.58, 0.94) |
| Breast biopsy ever | 1.44 (1.28, 1.63) | N/A |
| Current hormone therapy use | 1.52 (1.35, 1.71) | 0.74 (0.58, 0.94) |
| Menarche at less than 12 years of age | N/A | 0.77 (0.61, 0.98) |
| Never pregnant | N/A | N/A |
CI, confidence interval; FHLBC, family history of later-onset breast cancer; HR, hazard ratio; N/A, not applicable, because these factors were not associated with the component cause and thus are not potential confounding variables for the interaction contrast.