Table 2.

HR of breast cancer associated with physical activity in the JACC study

Physical activityCasesPerson-yearsAge adjusted
Multivariate*
HR (95% CI)HR (95% CI)
Time spent walking per day
    <30 min6996,7521.00 (Reference)1.00 (Reference)
    30–59 min5671,4111.14 (0.71 – 1.84)1.13 (0.80 – 1.61)
    ≥1 h82171,8920.70 (0.51 – 0.97)0.73 (0.53 – 1.01)
    P for trend0.0210.043
Time spent exercising per week
    Never or seldom161255,8291.00 (Reference)1.00 (Reference)
    1–2 h2951,0430.87 (0.59 – 1.30)0.83 (0.56 – 1.23)
    ≥3 h1733,1830.87 (0.53 – 1.45)0.85 (0.51 – 1.40)
    P for trend0.450.33
  • * Adjusted for age, BMI, alcohol drinking, age at menarche, education level, parity, age at birth of first child, use of exogenous female hormone, family history of breast cancer in a first-degree relative, menopausal status, and menopausal age for postmenopausal women.