Table 3.

Multivariable^* Relative Risks of Breast Cancer by AR Status According to Physical Activity in the Nurses’ Health Study (1986–2006).

	Overall invasive breast cancer (n=5,410)	Not accounting for ER/PR status			Accounting for ER/PR status
Physical activity (MET-hrs/wk)		AR+ (n=1,661)	AR− (n=467)	P- het†	AR+ (n=1,661)	AR− (n=467)	P- het†
<3	1.0 (ref.)	1 (ref.)	1 (ref.)		1 (ref.)	1 (ref.)
3–<9	0.99 (0.91, 1.08)	0.95 (0.82, 1.11)	0.99 (0.74, 1.32)		0.95 (0.81, 1.11)	0.99 (0.71, 1.38)
9–<18	0.93 (0.85, 1.02)	0.88 (0.75, 1.03)	1.10 (0.83, 1.47)		0.84 (0.72, 0.99)	1.16 (0.83, 1.60)
18–<27	0.94 (0.85, 1.03)	0.91 (0.76, 1.09)	0.97 (0.70, 1.36)		0.90 (0.75, 1.08)	1.04 (0.71, 1.51)
≥ 27	0.86 (0.78, 0.95)	0.89 (0.75, 1.06)	0.74 (0.52, 1.04)	0.34	0.85 (0.71, 1.01)	0.73 (0.49, 1.07)	0.47
p-trend	<0.001	0.21	0.08		0.12	0.05
Per 20 MET-hrs/wk (equivalent to 5 hours of brisk walking per week)	0.89 (0.81, 0.98)	0.83 (0.70, 0.98)	0.67 (0.47, 0.95)	0.28	0.87 (0.73, 1.04)	0.67 (0.45, 0.99)	0.22

^*MV-Adjusted for age at menarche, body mass index at age 18 years, height, parity and age at first birth, alcohol intake, postmenopausal hormone use, age at menopause, family history of breast cancer, and history of benign breast disease.

^†p-value for heterogeneity between AR+ and AR− tumors.