Intensity and timing of physical activity in relation to postmenopausal breast cancer risk: the prospective NIH-AARP Diet and Health Study

Table 5 Relative risk (RR) and 95% confidence intervals (CI) for the association of moderate-to-vigorous physical activity during four periods of life with breast cancer incidence: 118,899 postmenopausal women in the NIH-AARP Diet and Health Study

Moderate-to-vigorous activity	No. cancers* n = 4287	RR^†	95% CI	RR^††	95% CI		RR^§	95% CI		RR^£	95% CI
Ages 15-18 years
Never/Rarely	541	1.00 (ref.)		1.00 (ref.)			1.00 (ref.)			1.00 (ref.)
<1 hour/week	394	1.11	0.98, 1.27	1.12	0.98	1.27	1.10	0.97	1.26	1.12	0.98	1.27
1-3 hours/week	936	1.05	0.95, 1.17	1.05	0.94	1.17	1.04	0.93	1.16	1.05	0.94	1.16
4-7 hours/week	950	1.02	0.92, 1.14	1.01	0.91	1.13	1.00	0.89	1.12	1.01	0.91	1.13
>7 hours/week	1415	1.02	0.92, 1.12	1.03	0.93	1.14	1.02	0.91	1.14	1.02	0.93	1.13
Ages 19-29 years
Never/Rarely	415	1.00 (ref.)		1.00 (ref.)			1.00 (ref.)			1.00 (ref.)
<1 hour/week	384	1.09	0.95, 1.25	1.08	0.94	1.24	1.07	0.93	1.23	1.08	0.94	1.24
1-3 hours/week	976	1.07	0.95, 1.20	1.06	0.94	1.19	1.05	0.93	1.18	1.06	0.94	1.19
4-7 hours/week	1080	1.00	0.89, 1.12	1.01	0.90	1.13	1.01	0.89	1.13	1.01	0.90	1.13
>7 hours/week	1375	0.97	0.87, 1.08	1.01	0.90	1.13	1.02	0.90	1.15	1.01	0.90	1.13
Ages 35-39 years
Never/Rarely	392	1.00 (ref.)		1.00 (ref.)			1.00 (ref.)			1.00 (ref.)
<1 hour/week	421	1.12	0.98, 1.28	1.11	0.97	1.27	1.09	0.95	1.25	1.11	0.97	1.27
1-3 hours/week	963	1.00	0.89, 1.13	0.99	0.88	1.11	0.98	0.87	1.11	0.99	0.88	1.12
4-7 hours/week	1174	1.03	0.92, 1.16	1.03	0.92	1.15	1.04	0.92	1.18	1.04	0.93	1.16
>7 hours/week	1288	0.94	0.84, 1.06	0.97	0.87	1.09	0.99	0.87	1.12	0.98	0.88	1.10
Past 10 years
Never/Rarely	646	1.00 (ref.)		1.00 (ref.)			1.00 (ref.)			1.00 (ref.)
<1 hour/week	507	1.06	0.94, 1.19	1.05	0.94	1.18	1.03	0.92	1.16	1.06	0.94	1.19
1-3 hours/week	1071	0.93	0.84, 1.02	0.91	0.83	1.00	0.90	0.81	1.00	0.93	0.84	1.02
4-7 hours/week	1106	0.94	0.86, 1.04	0.92	0.83	1.01	0.91	0.82	1.01	0.94	0.85	1.04
>7 hours/week	928	0.84	0.76, 0.93	0.84	0.76	0.93	0.85	0.76	0.95	0.87	0.78	0.96

Number of cancer cases may not add up to total (n = 4287) due to missing physical activity values
† Relative risks adjusted for age (continuous)
†† Relative risks adjusted for: age (continuous); race/ethnicity (white, black, Hispanic, Asian/Pacific Islander/American Indian); education level (<12 years or high school equivalent, 12 years or high school equivalent, post-high school vocational or technical training, some college, college graduate, post-graduate); smoking status (non-smoker, former, current); alcohol intake (grams/day, quintiles adjusted for total energy intake); family history of breast cancer (no, yes); age at menarche (<13, 13-14, ≥ 15 years); age at first birth (nulliparous, <20, 20-24, 25-29, 30+ years); parity (number of children: 0, 1-2, 3 or more); age at menopause (<40, 40-44, 45-49, 50-54, ≥ 55 years); menopausal hormone use (never, ever)
§Relative risks additionally adjusted for frequency of other type of physical activity (either light or moderate-to-vigorous) during that same time period
£ Relative risks additionally adjusted for body mass index (BMI: <25.0, 25.0-29.9, 30.0-34.9, ≥ 35.0 kg/m²)

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