Table 5.
Hazard ratios and 95% confidence intervals for pre- to post-diagnosis change in lifestyle factors and the risk of a second breast cancer diagnosis: WISC DCIS cohort, 1997-2010
| All second breast cancer diagnoses |
Invasive second breast cancer diagnoses |
|||||
|---|---|---|---|---|---|---|
| Second diagnosis | HR (95% CI)b | Ptrendc | Second diagnosis | HR (95% CI)b | Ptrendc | |
| Change in BMIa,d | ||||||
| Decrease > 0.13 kg/m2 per year | 33 | 0.95 (0.55, 1.63) | 0.61 | 13 | 1.06 (0.43, 2.65) | 0.33 |
| Stable within ± 0.13 kg/m2 per year | 36 | 1.00 (Ref) | 12 | 1.00 (Ref) | ||
| Increase > 0.13 kg/m2 per year | 71 | 0.88 (0.55, 1.41) | 27 | 1.00 (0.44, 2.26) | ||
| Continuous for 1 kg/m2 per year change | 140 | 0.98 (0.84, 1.15) | 52 | 0.93 (0.71, 1.21) | ||
| Change in Total Physical Activitya,d | ||||||
| Decrease > 0.13 hours/week per year | 19 | 0.95 (0.48, 1.88) | 0.45 | 6 | 1.00 (0.30, 3.46) | 0.33 |
| Stable within ± 0.13 hours/week per year | 24 | 1.00 (Ref) | 7 | 1.00 (Ref) | ||
| Increase > 0.13 hours/week per year | 11 | 0.74 (0.35, 1.57) | 5 | 1.04 (0.30, 3.67) | ||
| Continuous for 1 hour/week change | 54 | 0.93 (0.73, 1.20) | 18 | 1.02 (0.61, 1.68) | ||
| Change in Total Alcohola,d | ||||||
| Decrease > 0.064 drinks/week per year | 7 | 0.73 (0.32, 1.66) | 0.13 | 3 | 0.62 (0.15, 2.72) | 0.13 |
| Stable within ± 0.064 drinks/week per year | 30 | 1.00 (Ref) | 8 | 1.00 (Ref) | ||
| Increase > 0.064 drinks/week per year | 17 | 1.58 (0.81, 3.06) | 7 | 1.79 (0.61, 5.47) | ||
| Continuous for 1 drink/week per year change | 54 | 1.01 (0.70, 1.46) | 18 | 1.23 (0.67, 2.16) | ||
Categories for BMI, physical activity, and alcohol intake represent the annualized change from pre-diagnosis to most recent post-diagnosis level (or last contact before a second breast diagnosis)
Adjusted for age at diagnosis, menopausal status, mode of detection, treatment type, postmenopausal hormone use, tamoxifen use, year of diagnosis, tumor size, tumor grade, physical activity, alcohol use, time since diagnosis, remaining lifetyle factors, and pre-diagnosis levels of each lifestyle factor
P value is for linear trend across categories of each change in lifestyle factor
Categories reflect a change of approximately 1 kg/m2 for BMI, 1 hour/week for physical activity, and 0.5 drinks/week for alcohol intake over the median follow-up period