Table 3 Associations between physical activity and mammographic breast density or BI-RADS density

Physical activity

MET-hours/week

 Low (< 28.5)

552 (54)

1.00 (REF)

1.00 (REF)

203 (55)

1.00 (REF)

1.00 (REF)

 High (≥ 28.5)

470 (46)

1.18 (0.91–1.53)

1.05 (0.79–1.40)

164 (45)

1.08 (0.71–1.65)

1.05 (0.66–1.65)

 Continuous

1022 (100)

1.00 (1.00*-1.01)

1.00 (1.00*-1.01)

367 (100)

1.00 (1.00*-1.01)

1.00 (1.00*-1.01)

WHO guidelines

 Subceed

116 (11)

1.00 (REF)

1.00 (REF)

54 (15)

1.00 (REF)

1.00 (REF)

 Adhere

224 (22)

0.94 (0.58–1.55)

0.96 (0.56–1.64)

77 (21)

1.21 (0.58–2.51)

1.15 (0.52–2.50)

 Exceed

682 (67)

1.40 (0.91–2.14)

1.24 (0.78–1.98)

236 (64)

1.45 (0.78–2.69)

1.40 (0.72–2.72)

 p-trend

0.023

0.176

0.215

0.269

Moderate intensity

 < 150 min

189 (19)

1.00 (REF)

1.00 (REF)

78 (21)

1.00 (REF)

1.00 (REF)

 150–300 min

307 (30)

1.14 (0.75–1.65)

1.18 (0.77–1.81)

111 (31)

1.19 (0.65–2.18)

1.30 (0.68–2.49)

 ≥ 300 min

513 (51)

1.40 (0.98–2.00)

1.36 (0.92–2.01)

174 (48)

1.43 (0.82–2.49)

1.43 (0.80–2.58)

 p-trend

0.043

0.110

0.191

0.245

Vigorous intensity

 < 75 min

510 (67)

1.00 (REF)

1.00 (REF)

192 (68)

1.00 (REF)

1.00 (REF)

 75–150 min

173 (23)

1.17 (0.81–1.67)

1.20 (0.80–1.78)

65 (23)

0.93 (0.52–1.67)

1.01 (0.54–1.89)

 ≥ 150 min

78 (10)

1.42 (0.87–2.31)

1.28 (0.75–2.20)

27 (10)

1.28 (0.57–2.88)

1.25 (0.49–3.14)

 p-trend

0.132

0.260

0.724

0.710