Brisk walking at baseline in relation to breast cancer overall, ER+, and ER− breast cancer
| All breast cancer | ER+ breast cancer | ER− breast cancer | |||||
|---|---|---|---|---|---|---|---|
| h/wk | Cases | Person-years | IRRa (95% CI) | Cases | IRR (95% CI) | Cases | IRR (95% CI) |
| <1 | 1,086 | 470,638 | 1.00 (Ref.) | 544 | 1.00 (Ref.) | 310 | 1.00 (Ref.) |
| 1 | 67 | 31,643 | 0.96 (0.75–1.22) | 36 | 1.02 (0.72–1.43) | 23 | 1.10 (0.72–1.68) |
| 2 | 59 | 32,662 | 0.79 (0.61–1.03) | 34 | 0.88 (0.62–1.25) | 14 | 0.63 (0.37–1.08) |
| 3–4 | 78 | 37,884 | 0.88 (0.69–1.11) | 36 | 0.77 (0.55–1.09) | 30 | 1.17 (0.79–1.71) |
| 5–6 | 40 | 20,299 | 0.84 (0.61–1.16) | 20 | 0.80 (0.51–1.27) | 16 | 1.14 (0.68–1.90) |
| 7+ | 29 | 17,057 | 0.77 (0.53–1.13) | 16 | 0.83 (0.50–1.38) | 10 | 0.88 (0.46–1.68) |
| Ptrend = 0.02 | Ptrend = 0.08 | Ptrend = 0.98 | |||||
NOTE: Walking defined as brisk based on fairly brisk or brisk pace reported on the 2003 or 2005 questionnaire
↵aIRRs adjusted for age (single year), time period (questionnaire cycle), BMI (<25, 25–29, ≥30 kg/m2), years of education (≤12, 13–15, 16, ≥17), parity (0, 1, 2, ≥3), vegetable/fruit dietary pattern (quintiles), meat/fried foods dietary pattern (quintiles), and vigorous exercise (<1, 1–4, ≥5 h/wk).