Background
Methods
Study population
Data collection
Statistical analyses
Results
Characteristics
Overall, % (n = 108,907) | Average annual total long-term RPA (h/wk/y), % | |||||
---|---|---|---|---|---|---|
≤0.50(n = 9984) | 0.51–2.50(n = 31,942) | 2.51–4.50(n = 25,442) | 4.51–7.00(n = 19,466) | ≥7.01(n = 22,073) | ||
Race | ||||||
White | 86.4 | 80.8 | 85.8 | 88.4 | 87.9 | 87.2 |
Black | 2.7 | 4.2 | 3.1 | 2.4 | 2.4 | 2.4 |
Hispanic | 4.5 | 5.0 | 4.4 | 3.9 | 4.1 | 4.1 |
Asian | 3.7 | 7.2 | 4.4 | 3.1 | 2.9 | 2.8 |
Others/unspecified | 2.8 | 2.8 | 2.3 | 2.2 | 2.6 | 3.5 |
First-degree family history of breast cancer | 11.7 | 12.7 | 12.5 | 12.0 | 11.5 | 11.3 |
History of a breast biopsy | 15.5 | 17.0 | 17.0 | 15.9 | 15.4 | 14.5 |
Had a mammogram in the 2 years prior to baseline | 74.3 | 84.9 | 83.1 | 80.5 | 77.0 | 73.1 |
BMI, kg/m2
| ||||||
<25.00 (under/normal weight) | 58.9 | 51.5 | 55.4 | 59.4 | 61.7 | 64.0 |
25.00–29.99 (overweight) | 23.9 | 25.8 | 24.9 | 24.3 | 23.0 | 21.7 |
≥30.00 (obese) | 13.9 | 13.9 | 16.7 | 13.7 | 12.9 | 11.5 |
Unknown | 3.3 | 4.8 | 2.9 | 2.6 | 2.4 | 2.8 |
Nulliparous | 26.7 | 21.7 | 22.2 | 23.6 | 26.5 | 31.3 |
Menopausal status and MHT use | ||||||
Premenopausal | 42.6 | 26.4 | 38.5 | 45.6 | 49.1 | 49.7 |
Peri-/postmenopausal | ||||||
No MHT | 10.6 | 15.1 | 9.7 | 8.3 | 7.9 | 9.1 |
E only | 14.4 | 17.6 | 14.0 | 11.4 | 10.8 | 11.3 |
E plus P only | 17.5 | 22.4 | 21.5 | 19.7 | 17.9 | 16.1 |
Mixed formulations | 6.5 | 7.9 | 6.4 | 5.6 | 5.3 | 5.0 |
Unknown MHT use | 4.3 | 6.0 | 4.4 | 3.8 | 3.6 | 3.4 |
Unknown MP status | 4.1 | 4.6 | 5.7 | 5.6 | 5.4 | 5.6 |
History of cigarette smoking | ||||||
Never | 66.5 | 66.5 | 65.8 | 64.8 | 65.7 | 65.7 |
Former | 28.4 | 27.7 | 29.0 | 30.4 | 29.3 | 28.5 |
Current | 5.2 | 5.9 | 5.2 | 4.9 | 5.0 | 5.8 |
Alcohol intake during the year prior to baseline | ||||||
Nondrinker | 31.7 | 40.4 | 33.7 | 29.6 | 28.7 | 28.2 |
<15 g/d | 47.9 | 41.3 | 47.9 | 50.6 | 50.6 | 50.1 |
≥15 g/d | 15.9 | 13.4 | 14.7 | 16.4 | 17.1 | 18.0 |
Unknown | 4.5 | 4.9 | 3.7 | 3.4 | 3.6 | 3.7 |
Recreational physical activity and invasive breast cancer
h/wk/y | Observed person-years | Overall | TNBC (ER-/PR-/HER2-)a
| Luminal A-like (ER+ or PR+ plus HER2-)a
| |||
---|---|---|---|---|---|---|---|
Cases, no. | Adjusted HR (95 % CI) | Cases, no. | Adjusted HR (95 % CI) | Cases, no. | Adjusted HR (95 % CI) | ||
Total (strenuous plus moderate) RPA | |||||||
Long-termc
| |||||||
≤0.50 | 140,148 | 662 | Referent | 43 | Referent | 303 | Referent |
0.51–2.50 | 467,293 | 1923 | 0.98 (0.89–1.07) | 115 | 0.83 (0.58–1.18) | 886 | 0.95 (0.83–1.08) |
2.51–4.50 | 376,903 | 1319 | 0.91 (0.82–1.00) | 84 | 0.80 (0.55–1.16) | 589 | 0.84 (0.73–0.97) |
4.51–7.00 | 289,855 | 957 | 0.91 (0.82–1.00) | 45 | 0.58 (0.38–0.89) | 445 | 0.87 (0.75–1.01) |
≥7.01 | 327,027 | 1021 | 0.90 (0.81–0.99) | 61 | 0.73 (0.49–1.09) | 478 | 0.87 (0.75–1.00) |
P
trend
|
0.01
|
0.11
|
0.05
| ||||
Homogeneity of trends between two subtypes |
P = 0.38
| ||||||
Baselined
| |||||||
≤0.50 | 355,905 | 1438 | Referent | 98 | Referent | 639 | Referent |
0.51–2.50 | 457,799 | 1708 | 0.97 (0.90–1.04) | 96 | 0.77 (0.58–1.02) | 787 | 0.99 (0.89–1.10) |
2.51–4.50 | 279,320 | 972 | 0.90 (0.83–0.98) | 61 | 0.80 (0.58–1.11) | 468 | 0.96 (0.85–1.08) |
4.51–7.00 | 256,204 | 901 | 0.88 (0.81–0.96) | 44 | 0.61 (0.43–0.88) | 412 | 0.89 (0.78–1.01) |
≥7.01 | 251,999 | 863 | 0.87 (0.80–0.95) | 49 | 0.72 (0.50–1.02) | 395 | 0.88 (0.77–1.00) |
P
trend
|
<0.001
|
0.07
|
0.01
| ||||
Homogeneity of trends between two subtypes |
P = 0.34
| ||||||
Strenuous RPAb
| |||||||
Long-termc
| |||||||
≤0.50 | 449,871 | 2069 | Referent | 122 | Referent | 936 | Referent |
0.51–2.00 | 522,886 | 1 900 | 0.93 (0.87–0.99) | 115 | 0.89 (0.68–1.16) | 865 | 0.92 (0.84–1.02) |
2.01–3.50 | 293,055 | 908 | 0.88 (0.81–0.96) | 62 | 0.93 (0.67–1.29) | 430 | 0.91 (0.80–1.02) |
3.51–5.00 | 160,273 | 523 | 0.99 (0.89–1.09) | 27 | 0.76 (0.49–1.19) | 237 | 0.96 (0.83–1.12) |
≥5.01 | 175,143 | 482 | 0.87 (0.78–0.97) | 22 | 0.52 (0.31–0.87) | 233 | 0.92 (0.78–1.08) |
P
trend
|
0.03
|
0.02
|
0.35
| ||||
Homogeneity of trends between two subtypes |
P = 0.05
| ||||||
Baselined
| |||||||
≤50 | 894,810 | 3654 | Referent | 224 | Referent | 1675 | Referent |
0.51–2.00 | 322,058 | 1066 | 0.95 (0.89–1.02) | 70 | 1.00 (0.76–1.32) | 478 | 0.91 (0.82–1.01) |
2.01–3.50 | 157,265 | 460 | 0.83 (0.75–0.92) | 26 | 0.73 (0.48–1.11) | 216 | 0.81 (0.70–0.94) |
3.51–5.00 | 153,597 | 476 | 0.94 (0.85–1.04) | 14 | 0.42 (0.24–0.73) | 229 | 0.95 (0.83–1.10) |
≥5.01 | 73,497 | 226 | 0.90 (0.78–1.04) | 14 | 0.83 (0.47–1.47) | 103 | 0.88 (0.72–1.09) |
P
trend
|
0.01
|
0.01
|
0.06
| ||||
Homogeneity of trends between two subtypes |
P = 0.08
| ||||||
Moderate RPAb
| |||||||
Long-termc
| |||||||
≤0.50 | 321,926 | 1314 | Referent | 79 | Referent | 630 | Referent |
0.51–2.00 | 582,646 | 2134 | 0.99 (0.93–1.07) | 134 | 0.99 (0.74–1.32) | 954 | 0.90 (0.81–1.00) |
2.01–3.50 | 330,827 | 1175 | 0.99 (0.91–1.07) | 62 | 0.85 (0.60–1.20) | 550 | 0.93 (0.83–1.05) |
3.51–5.00 | 185,859 | 637 | 0.97 (0.88–1.07) | 30 | 0.79 (0.51–1.22) | 293 | 0.89 (0.77–1.03) |
≥5.01 | 179,970 | 622 | 0.99 (0.89–1.10) | 43 | 1.34 (0.89–2.02) | 274 | 0.87 (0.74–1.01) |
P
trend
|
0.66
|
0.42
|
0.13
| ||||
Homogeneity of trends between two subtypes |
P = 0.20
| ||||||
Baselined
| |||||||
≤0.50 | 519,391 | 1937 | Referent | 128 | Referent | 884 | Referent |
0.51–2.00 | 503,498 | 1788 | 1.00 (0.93–1.07) | 99 | 0.82 (0.62–1.07) | 808 | 0.98 (0.89–1.09) |
2.01–3.50 | 233,772 | 891 | 1.04 (0.96–1.13) | 51 | 0.93 (0.66–1.30) | 438 | 1.11 (0.99–1.25) |
3.51–5.00 | 226,867 | 799 | 0.91 (0.83–0.99) | 43 | 0.83 (0.58–1.19) | 366 | 0.90 (0.80–1.03) |
≥5.01 | 117,700 | 467 | 0.98 (0.88–1.09) | 27 | 0.98 (0.63–1.54) | 205 | 0.95 (0.80–1.11) |
P
trend
|
0.19
|
0.75
|
0.32
| ||||
Homogeneity of trends between two subtypes |
P = 0.98
|
Potential interaction between strenuous recreational physical activity and BMI at baseline
BMI, kg/m2
| Cases, no. | Strenuous RPA, h/wk/y |
P
trend
|
P
homogeneity of trends
| ||
---|---|---|---|---|---|---|
≤0.50 | 0.51–3.50 | ≥3.51 | ||||
Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | ||||
Among all women | ||||||
TNBC (ER-/PR-/HER2-) | ||||||
Long-terma
| ||||||
BMI <25 | 195 | Referent | 0.88 (0.64–1.22) | 0.62 (0.39–0.99) |
0.05
|
0.54
|
BMI ≥25 | 139 | Referent | 0.85 (0.59–1.24) | 0.78 (0.45–1.36) |
0.37
| |
Baselineb
| ||||||
BMI <25 | 195 | Referent | 1.04 (0.76–1.42) | 0.60 (0.37–0.97) |
0.05
|
0.40
|
BMI ≥25 | 139 | Referent | 0.72 (0.47–1.10) | 0.48 (0.21–1.10) |
0.04
| |
Luminal A-like (ER+ or PR+ plus HER2-) | ||||||
Long-terma
| ||||||
BMI <25 | 1484 | Referent | 0.95 (0.84–1.07) | 0.93 (0.79–1.09) |
0.39
|
0.71
|
BMI ≥25 | 1119 | Referent | 0.87 (0.76–0.99) | 0.90 (0.74–1.08) |
0.25
| |
Baselineb
| ||||||
BMI <25 | 1484 | Referent | 0.89 (0.79–1.00) | 0.88 (0.76–1.03) |
0.08
|
0.31
|
BMI ≥25 | 1119 | Referent | 0.87 (0.75–1.00) | 1.06 (0.86–1.32) |
0.99
| |
Among peri- and postmenopausal women at baseline | ||||||
TNBC (ER-/PR-/HER2-) | ||||||
Long-terma
| ||||||
BMI <25 | 118 | Referent | 1.01 (0.67–1.53) | 0.78 (0.41–1.47) |
0.45
|
0.99
|
BMI ≥25 | 89 | Referent | 0.89 (0.56–1.43) | 0.83 (0.40–1.73) |
0.60
| |
Baselineb
| ||||||
BMI <25 | 118 | Referent | 1.26 (0.83–1.90) | 0.69 (0.35–1.36) |
0.42
|
0.06
|
BMI ≥25 | 89 | Referent | 0.56 (0.31–1.02) | 0.28 (0.07–1.17) |
0.02
| |
Luminal A-like (ER+ or PR+ plus HER2-) | ||||||
Long-terma
| ||||||
BMI <25 | 940 | Referent | 0.97 (0.84–1.12) | 0.90(0.73–1.12) |
0.34
|
0.39
|
BMI ≥25 | 794 | Referent | 0.86 (0.73–1.00) | 0.80(0.63–1.02) |
0.06
| |
Baselineb
| ||||||
BMI <25 | 940 | Referent | 0.93 (0.80–1.09) | 0.86 (0.70–1.05) |
0.13
|
0.47
|
BMI ≥25 | 794 | Referent | 0.90 (0.75–1.07) | 1.01 (0.77–1.32) |
0.78
|
Potential interaction between strenuous recreational physical activity and MHT use variables among women who were peri- or postmenopausal at baseline
Cases, no. | Strenuous RPA, h/wk/y |
P
trend
|
P
homogeneity of trends
| |||
---|---|---|---|---|---|---|
≤0.50 | 0.51–3.50 | ≥3.51 | ||||
Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | ||||
TNBC (ER-/PR-/HER2-) | ||||||
Long-terma
| ||||||
Never MHT use at baseline | 37 | Referent | 1.43 (0.72–2.84) | 0.35 (0.08–1.56) |
0.23
|
0.32
|
Ever MHT use at baseline | 165 | Referent | 0.93 (0.66–1.32) | 0.91 (0.54–1.52) |
0.69
| |
Baselineb
| ||||||
Never MHT use at baseline | 37 | Referent | 0.92 (0.43–1.98) | 0.43 (0.10–1.83) |
0.26
|
0.65
|
Ever MHT use at baseline | 165 | Referent | 1.00 (0.70–1.44) | 0.60 (0.32–1.13) |
0.14
| |
Luminal A-like (ER+ or PR+ plus HER2-) | ||||||
Long-terma
| ||||||
Never MHT use at baseline | 315 | Referent | 0.92 (0.72–1.17) | 0.86 (0.61–1.20) |
0.36
|
0.75
|
Ever MHT use at baseline | 1357 | Referent | 0.92 (0.81–1.04) | 0.91 (0.76–1.09) |
0.28
| |
Baselineb
| ||||||
Never MHT use at baseline | 315 | Referent | 0.83 (0.63–1.09) | 0.73 (0.50–1.07) |
0.07
|
0.15
|
Ever MHT use at baseline | 1357 | Referent | 0.92 (0.81–1.05) | 0.97 (0.81–1.16) |
0.57
|
Cases, no. | Strenuous RPA, h/wk/y |
P
trend
|
P
homogeneity of trends
| |||
---|---|---|---|---|---|---|
≤0.50 | 0.51–3.50 | ≥3.51 | ||||
Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | Adjusted HR (95 % CI) | ||||
TNBC (ER-/PR-/HER2-) | ||||||
Long-terma
| ||||||
Type of MHT use | ||||||
E only | 47 | Referent | 0.80 (0.43–1.48) | 0.63 (0.23–1.71) |
0.34
|
0.29
|
E + P | 108 | Referent | 0.99 (0.64–1.52) | 1.12 (0.61–2.08) |
0.71
| |
Duration of MHT use | ||||||
<5 years | 80 | Referent | 0.98 (0.60–1.62) | 1.09 (0.55–2.19) |
0.80
|
0.53
|
≥5 years | 75 | Referent | 0.87 (0.53–1.42) | 0.81 (0.37–1.75) |
0.57
| |
Cessation of MHT use | ||||||
Former MHT use | 24 | Referent | 1.00 (0.42–2.38) | 0.81 (0.22–3.02) |
0.77
|
0.81
|
Recent MHT use | 131 | Referent | 0.91 (0.61–1.34) | 0.98 (0.55–1.74) |
0.92
| |
Baselineb
| ||||||
Type of MHT use | ||||||
E only | 47 | Referent | 0.93 (0.47–1.87) | 0.89 (0.31–2.56) |
0.80
|
0.60
|
E + P | 108 | Referent | 0.98 (0.63–1.52) | 0.58 (0.26–1.28) |
0.20
| |
Duration of MHT use | ||||||
<5 years | 80 | Referent | 1.00 (0.61–1.66) | 0.46 (0.16–1.28) |
0.17
|
0.40
|
≥5 years | 75 | Referent | 0.93 (0.54–1.60) | 0.90 (0.40–2.02) |
0.76
| |
Cessation of MHT use | ||||||
Former MHT use | 24 | Referent | 0.58 (0.20–1.72) | 0.35 (0.05–2.64) |
0.21
|
0.30
|
Recent MHT use | 131 | Referent | 1.05 (0.70–1.56) | 0.73 (0.37–1.44) |
0.43
| |
Luminal A-like (ER+ or PR+ plus HER2-) | ||||||
Long-terma
| ||||||
Type of MHT use | ||||||
E only | 375 | Referent | 1.00 (0.80–1.25) | 0.84 (0.60–1.17) |
0.31
|
0.75
|
E + P | 931 | Referent | 0.89 (0.77–1.02) | 0.90 (0.73–1.11) |
0.32
| |
Duration of MHT use | ||||||
<5 years | 580 | Referent | 0.81 (0.67–0.97) | 0.90 (0.70–1.16) |
0.41
|
0.89
|
≥5 years | 726 | Referent | 1.01 (0.86–1.19) | 0.86 (0.67–1.10) |
0.26
| |
Cessation of MHT use | ||||||
Former MHT use | 171 | Referent | 0.84 (0.61–1.16) | 0.52 (0.30–0.89) |
0.02
|
0.03
|
Recent MHT use | 1135 | Referent | 0.93 (0.82–1.06) | 0.95 (0.78–1.15) |
0.59
| |
Baselineb
| ||||||
Type of MHT use | ||||||
E only | 375 | Referent | 0.82 (0.63–1.06) | 0.94 (0.67–1.32) | 0.49 | 0.65 |
E + P | 931 | Referent | 0.96 (0.82–1.12) | 0.98 (0.79–1.21) | 0.75 | |
Duration of MHT use | ||||||
<5 years | 580 | Referent | 0.91 (0.75–1.11) | 0.86 (0.65–1.14) |
0.24
|
0.29
|
≥5 years | 726 | Referent | 0.92 (0.77–1.10) | 1.05 (0.83–1.33) |
0.83
| |
Cessation of MHT use | ||||||
Former MHT use | 171 | Referent | 0.96 (0.67–1.36) | 0.44 (0.22–0.87) |
0.02
|
0.02
|
Recent MHT use | 1135 | Referent | 0.92 (0.79–1.06) | 1.05 (0.87–1.27) |
0.84
|
Changes in the levels of strenuous recreational physical activity and breast cancer risk
RPA at baselinea, h/wk/y | RPA at 10-year follow-upb, h/wk/y | Overall | Observed person-years | Cases, no. | Adjusted HR (95 % CI) |
---|---|---|---|---|---|
Breast cancer overall | |||||
No change | |||||
Low (≤0.50) | Low (≤0.50) | 24,028 | 396,185 | 692 | Referent |
Intermediate (0.51–3.50) | Intermediate (0.51–3.50) | 6273 | 104,479 | 155 | 1.01 (0.84–1.21) |
High (≥3.51) | High (≥3.51) | 2462 | 41,105 | 42 | 0.71 (0.52–0.98) |
Increasing | |||||
Low (≤0.50) | Intermediate (0.51–3.50) | 5640 | 93,840 | 127 | 0.86 (0.71–1.04) |
Low (≤0.50) | High (≥3.51) | 1267 | 21,076 | 34 | 1.03 (0.72–1.45) |
Intermediate (0.51–3.50) | High (≥3.51) | 1751 | 29,121 | 40 | 0.89 (0.64–1.23) |
Decreasing | |||||
Intermediate (0.51–3.50) | Low (≤0.50) | 8436 | 139,718 | 209 | 0.96 (0.82–1.12) |
High (≥3.51) | Low (≤0.50) | 2212 | 36,515 | 58 | 1.00 (0.76–1.32) |
High (≥3.51) | Intermediate (0.51–3.50) | 2617 | 43,519 | 46 | 0.75 (0.55–1.02) |