Skip to main content

Table 4 Multivariable associations between physical activity and absolute dense volume (cm 3 ) stratified by 10-year breast cancer risk estimated by the Tyrer–Cuzick prediction model

From: Background risk of breast cancer and the association between physical activity and mammographic density

  Breast cancer risk <3.0% Breast cancer risk 3.0 to 4.9% Breast cancer risk ≥5.0%
Type of activity N % Multivariable-adjusted N % Multivariable-adjusted N % Multivariable-adjusted
β (95% CI) a β (95% CI) a    β (95% CI) a
Total activity (MET-hours/day)          
 < 40.0 5,791 29.5 Reference 4,499 32.6 Reference 1,890 34.4 Reference
 40 to 44.9 7,515 38.3 −1.9 (−3.1, −0.7) 5,567 40.4 −0.3 (−1.7, 1.0) 2,191 39.9 −0.7 (−2.7, 1.3)
 45.0 to 49.9 4,072 20.7 −3.3 (−4.7, −1.9) 2,520 18.3 −2.0 (−3.6, −0.4) 999 18.2 −0.5 (−3.2, 2.1)
 ≥ 50.0 2,255 11.5 −4.2 (−5.8, −2.6) 1,199 8.7 −2.2 (−4.4, 0) 415 7.6 −3.7 (−7.1, −0.3)
P global b    <0.001    0.04    0.2
 For every 5 MET-hours/day increasec    −1.2 (−1.5, −0.8)    −0.7 (−1.2, −0.2)    −1.0 (−1.9, −0.3)
P trend d    <0.001    0.01    0.01
P interaction e    0.05       
Moderate activity (hours/day)          
 < 2.0 7,173 36.5 Reference 5,623 40.8 Reference 2,308 42.0 Reference
 2.0 to 4.9 6,100 31.1 0 (−1.2, 1.2) 4,431 32.1 −0.4 (−1.7, 0.9) 1,769 32.2 −0.7 (−2.7, 1.3)
 5.0 to 6.9 3,061 15.6 −1.1 (−2.6, 0.3) 1,920 13.9 −0.7 (−2.4, 1.0) 748 13.6 −0.7 (−3.5, 2.1)
 ≥ 7.0 3,299 16.8 −2.4 (−3.8, −1.0) 1,811 13.1 −1.1 (−2.9, 0.7) 670 12.2 −0.8 (−3.7, 2.0)
P global    <0.001    0.65    0.88
 For every 1 hour/day increasec    −0.3 (−0.5, −0.1)    −0.1 (−0.4, 0.1)    −0.1 (−0.5, 0.2)
P trend d    <0.001    0.14    0.40
P interaction e    0.13       
Vigorous activity (hours/day)          
 < 0.25 14,190 72.3 Reference 10,262 74.4 Reference 4,107 74.7 Reference
 0.25 to 0.49 3,293 16.8 −2.8 (−4.1, −1.5) 2,118 15.4 −2.3 (−3.9, −0.7) 826 15.0 −2.2 (−4.7, 0.4)
 0.5 to 0.9 1,699 8.7 −3.3 (−5.0, −1.7) 1,084 7.9 −3.3 (−5.3, −1.2) 443 8.1 −4.4 (−7.2, −1.6)
 ≥ 1.0 451 2.3 −6.3 (−9.1, −3.5) 321 2.3 0.5 (−3.0, 4.1) 119 2.2 −0.2 (−5.9, 5.5)
P global    <0.001    <0.001    0.01
 For every 1 hour/day increasec    −5.5 (−7.0, −4.1)    −1.7 (−3.3, −0.03)    −3.7 (−6.2, −1.1)
P trend d    <0.001    0.05    0.01
P interaction e    0.11       
Recreational activity (hours/day)          
 < 0.5 1,068 5.4 Reference 866 6.3 Reference 348 6.3 Reference
 0.5 to 0.9 2,450 12.5 0.8 (−1.7, 3.2) 1,906 13.8 −1.4 (−4.2, 1.3) 814 14.8 −3.0 (−7.0, 1.1)
 1.0 to 2.9 10,336 52.6 −1.3 (−3.4, 0.7) 7,514 54.5 −1.8 (−4.2, 0.6) 3,010 54.8 −1.6 (−5.2, 2.1)
 ≥ 3.0 5,779 29.4 −2.1 (−4.3, 0.1) 3,499 25.4 −2.4 (−5.0, 0.1) 1,323 24.1 −3.2 (−7.1, 0.7)
P global    0.01    0.3    0.24
 For every 1 hour/day increasec    −0.5 (−0.8, −0.2)    −0.3 (−0.6, 0.1)    −0.6 (−1.2, −0.1)
P trend d    <0.001    0.15    0.03
P interaction e    0.37       
  1. β, regression coefficient; CI, confidence interval; MET, metabolic equivalent of task. aAdjusted for age at mammography (5-year categories), body mass index (<25.0, 25.0 to 29.9, ≥30.0 kg/m2), family history of breast cancer in mother or sisters (yes, no), age at menarche (<13, 13, 14, ≥15 years), parity and age at first birth (nulliparous; one or two births, age at first birth <26 years; one or two births, age at first birth ≥26 years; ≥3 births, age at first birth <26 years; ≥3 births, age at first birth ≥26 years), oral contraceptives use (never, ever), menopausal status (premenopausal, postmenopausal), use of hormone replacement therapy (never, past, current), education level (secondary school, high school, university or higher, other), smoking status (never, past, current) and alcohol consumption (none, 0.1 to 9.9, 10.0 to 29.9, ≥30.0 g/day). b P global values were obtained from regression models using physical activity as a categorical exposure. cChange in volumetric mammographic density for every 5 MET-hours/day increase in total activity or every 1 hour/day increase in moderate, vigorous or recreational activity, respectively; from regression models using physical activity as a continuous exposure. d P trend values were obtained from regressions models using physical activity as a continuous exposure. e P interaction values were obtained from the nonstratified regression models by adding a product term between physical activity and the 10-year breast cancer risk as predicted using the Tyrer–Cuzick prediction model.
\