Table 2.
Association between postdiagnosis overall and moderate and vigorous physical activity and survival following breast cancer diagnosis: NHS (1986-2016) and NHSII (1989-2017)a
| Activity type and outcome | MET hours of physical activity per weekb |
P trend | ||||
|---|---|---|---|---|---|---|
| <3 | 3 to <9 | 9 to <18 | 18 to <27 | ≥27 | ||
| HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | HR (95% CI) | ||
| Total physical activity | ||||||
| Breast cancer–specific death (n = 891) | ||||||
| No./person-years | 122/10 012 | 251/29 982 | 240/34 483 | 130/19 605 | 146/23 363 | |
| Multivariable adjusted | Referent | 0.79 (0.59 to 1.06) | 0.74 (0.55 to 0.99) | 0.68 (0.49 to 0.95) | 0.69 (0.50 to 0.95) | .04 |
| Multivariable adjusted + prediagnosis PAc | Referent | 0.73 (0.54 to 1.00) | 0.64 (0.45 to 0.89) | 0.56 (0.38 to 0.84) | 0.56 (0.38 to 0.84) | .02 |
| Overall death (n = 1973) | ||||||
| No./person-years | 278/10 012 | 567/29 982 | 559/34 483 | 290/19 605 | 277/23 363 | |
| Multivariable adjusted | Referent | 0.73 (0.61 to 0.88) | 0.67 (0.55 to 0.80) | 0.65 (0.53 to 0.81) | 0.51 (0.41 to 0.63) | <.001 |
| Multivariable adjusted + prediagnosis PAc | Referent | 0.73 (0.60 to 0.88) | 0.65 (0.53 to 0.80) | 0.62 (0.49 to 0.79) | 0.47 (0.36 to 0.61) | <.001 |
| Moderate and vigorous physical activity | ||||||
| Breast cancer–specific death (n = 866) | ||||||
| No./person-years | 581/71 191 | 164/26 805 | 83/13 605 | 25/3648 | 11/1933 | |
| Multivariable adjusted | Referent | 0.84 (0.67 to 1.05) | 0.90 (0.67 to 1.22) | 0.88 (0.51 to 1.51) | 0.54 (0.23 to 1.24) | .13 |
| Multivariable adjusted + prediagnosis PAc | Referent | 0.83 (0.66 to 1.04) | 0.88 (0.65 to 1.21) | 0.85 (0.49 to 1.49) | 0.52 (0.22 to 1.22) | .12 |
| Overall death (n = 1891) | ||||||
| No./person-years | 1359/71 191 | 330/26 805 | 144/13 605 | 41/3648 | 15/1933 | |
| Multivariable adjusted | Referent | 0.74 (0.64 to 0.86) | 0.69 (0.56 to 0.85) | 0.74 (0.50 to 1.09) | 0.50 (0.27 to 0.96) | <.001 |
| Multivariable adjusted + prediagnosis PAc | Referent | 0.76 (0.65 to 0.89) | 0.71 (0.57 to 0.88) | 0.76 (0.51 to 1.13) | 0.52 (0.27 to 0.99) | <.001 |
Multivariable models adjusted for estrogen receptor (ER) and progesterone receptor (PR) status, treatment with tamoxifen, aromatase inhibitor, Herceptin, and/or chemotherapy, stage at diagnosis (I-III), prediagnosis hormone therapy use, prediagnosis BMI, BMI change from prediagnosis to current, alcohol consumption, smoking status, aspirin use, and neighborhood SES. BMI = body mass index; CI = confidence interval; HR = hazard ratio; MET = metabolic equivalent task; NHS = Nurses’ Health Study; NHSII = Nurses’ Health Study II; PA = physical activity; SES = socioeconomic status.
Physical activity reported at least 12 months following diagnosis with cumulative average of reported activity over follow-up. Note: 3-9 MET-h/wk corresponds to an activity level comparable to approximately 1-3 h/wk of walking at pace of 2.5 mph.
Additionally adjusted for prediagnosis physical activity.