Table 5.
Independent effects of moderate-to-vigorous activity and sedentary time on breast cancer odds, by menopausal status and body mass index (BMI)†
| Average minutes per day* |
Menopausal Status |
BMI (kg/m2)** |
|||
|---|---|---|---|---|---|
| Premenopausal cases/controls (250/376) |
Postmenopausal cases/controls (746/788) |
< 25 cases/controls (473/485) |
25-30 cases/controls (348/416) |
≥ 30 cases/controls (148/221) |
|
| Moderate-to-vigorous, min/day |
|||||
| ≤ 65.09 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| 65.10 - 95.58 | 0.42 (0.25, 0.71) | 0.62 (0.46, 0.84) | 0.43 (0.28, 0.64) | 0.72 (0.46, 1.14) | 0.66 (0.34, 1.27) |
| 95.59 - 128.24 | 0.30 (0.17, 0.53) | 0.36 (0.25, 0.53) | 0.30 (0.19, 0.47) | 0.36 (0.22, 0.62) | 0.48 (0.20, 1.14) |
| ≥128.25 | 0.27 (0.13, 0.54) | 0.36 (0.23, 0.57) | 0.19 (0.11, 0.35) | 0.50 (0.27, 0.94) | 0.36 (0.13, 1.03) |
| P-trend | 0.0003 | <.0001 | <.0001 | 0.005 | 0.04 |
| P-interaction | 0.96 | 0.53 | |||
| Sedentary, min/day | |||||
| ≤ 396.60 | 1.00 | 1.00 | 1.00 | 1.00 | 1.00 |
| 396.61 - 457.74 | 1.42 (0.81, 2.49) | 1.27 (0.88, 1.84) | 0.94 (0.59, 1.49) | 1.65 (0.97, 2.78) | 1.66 (0.73, 3.78) |
| 457.75 - 524.10 | 1.46 (0.79, 2.73) | 1.42 (0.96, 2.10) | 0.69 (0.41, 1.15) | 2.18 (1.26, 3.78) | 2.17 (0.93, 5.06) |
| ≥ 524.11 | 2.10 (1.00, 4.42) | 1.63 (1.04, 2.55) | 0.88 (0.48, 1.59) | 3.13 (1.63, 6.01) | 2.18 (0.85, 5.62) |
| P-trend | 0.07 | 0.03 | 0.60 | 0.0006 | 0.11 |
| P-interaction | 0.37 | 0.005 | |||
Time spent sedentary or in moderate-to-vigorous activity calculated as the average minutes per day across valid days of wear. Categories determined by the quartile distribution among controls; behavior defined by the following counts: sedentary (0-99 counts) and moderate-to-vigorous (760+ counts); data for moderate-to-vigorous activity missing for one case. Models include time spent in moderate-to-vigorous and sedentary behavior.
Multivariable models adjusted for the following: age, BMI, education, current smoking status, age at menarche, number of full term births,breast cancer family history, previous screening mammogram, history of benign breast disease, menopausal status/age at menopause combination variable, and wear time. BMI and menopausal status excluded from their respective models.
BMI analyses excluded those with missing BMI values; unknown categories for age at menarche and education were also excluded due to too few numbers.