Table 2. Vigorous exercise at baseline in relation to incidence of breast cancer overall and ER+ and ER- breast cancer.

	All breast cancer			ER+ breast cancer		ER- breast cancer
hrs/wk	Cases	Person years	IRR* (95% CI)	Cases	IRR (95% CI)	Cases	IRR (95% CI)
< 1	773	313,900	1.00 (Ref.)	382	1.00 (Ref.)	228	1.00 (Ref.)
1	117	62,939	0.85 (0.70, 1.03)	59	0.86 (0.66, 1.14)	35	0.83 (0.58, 1.18)
2	149	67,081	0.99 (0.83, 1.19)	76	1.00 (0.78, 1.29)	45	1.00 (0.72, 1.38)
3-4	159	77,243	0.94 (0.79, 1.12)	84	0.98 (0.77, 1.25)	45	0.88 (0.63, 1.22)
5-6	69	35,793	0.89 (0.69, 1.14)	36	0.92 (0.65, 1.30)	23	0.97 (0.63, 1.50)
≥ 7	63	39,593	0.74 (0.57, 0.96)	32	0.75 (0.52, 1.09)	22	0.85 (0.55, 1.33)
			P trend = 0.05		P trend= 0.28		P trend=0.43

^*IRRs adjusted for age (single year), time period (questionnaire cycle), years of education (≤12, 13-15, 16, ≥17), parity (0, 1, 2, ≥3), vegetable/fruit dietary pattern (quintiles), and meat/fried foods dietary pattern (quintiles)