|
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)
|
- Results are for 54,686 women who completed baseline and 10-year follow-up questionnaires regarding RPA in recent 3 years in the California Teachers Study, 1995–2012. HRs are from multivariable Cox proportional hazards regression models using age (in days) as the time metric and stratified by age (in years) with the adjustment for race, family history of breast cancer in first-degree relatives, combined age at first full-term pregnancy and parity variable, combined menopausal status and MHT use variable, BMI at baseline, history of smoking, alcohol intake during the past year of baseline, screening mammogram in the past 2 years of baseline, history of a breast biopsy, and a corresponding changes in level of moderate RPA variable
-
Abbreviations: BMI body mass index, CI confidence interval, HR hazard ratio, h/wk/y hour/week/year, MHT menopausal hormone therapy, RPA recreational physical activity
-
aRPA during the 3 years prior to baseline
-
bRPA during the 3 years prior to 10-year follow-up
