Table 3

Odds ratio estimates of high-risk mammographic patternsa associated with indices of physical activity, according to parity and body mass index, surveyed at a population screening, Tromsø, Norway, 1979–1980 and 1986–1987

ParousBody mass index
Yes n = 2430 OR (95% CI)No n = 220 OR (95% CI)<22.4 kg/m2n = 919 OR (95% CI)22.4–25.0 kg/m2n = 915 OR (95% CI)>25.0 kg/m2n = 844 OR (95% CI)
Hours physically activeb in 1986–1987
 Seldom/never1.01.01.01.01.0
 ≤2 hr/week0.9 (0.7–1.2)0.9 (0.4–1.7)0.8 (0.6–1.1)1.1 (0.8–1.6)1.1 (0.7–1.8)
 >2 hr/week0.8 (0.6–1.2)0.3 (0.1–1.0)0.7 (0.4–1.1)0.9 (0.5–1.6)0.7 (0.3–1.6)
Work time physical activityc in 1979–1980 and 1986–1987
 Sedentary (both times)1.01.01.01.01.0
 Some/mixture0.9 (0.7–1.2)0.7 (0.4–1.4)0.8 (0.6–1.2)1.0 (0.6–1.4)1.8 (0.9–3.7)
 Moderate (both times)0.8 (0.4–1.3)0.6 (0.1–2.9)0.7 (0.3–1.5)0.5 (0.2–1.3)1.8 (0.7–4.8)
Leisure time activity in 1979–1980 and 1986–1987
 Sedentary (both times)1.01.01.01.01.0
 Some/mixture1.0 (0.7–1.4)1.5 (0.5–4.5)0.9 (0.5–1.4)1.1 (0.6–2.2)2.0 (0.8–5.3)
 Moderate (both times)0.8 (0.4–1.5)2.5 (0.3–14.0)0.9 (0.4–2.0)0.7 (0.2–2.0)0.8 (0.1–7.6)
  • a Low-risk patterns are I–III (reference group), and high-risk patterns are IV and V. All ORs are adjusted for age, education, menopausal status, age at menarche, alcohol intake, and oral contraceptive use. Those stratified by parity are also adjusted for body mass index, and those stratified by body mass index are also adjusted for number of children. Sedentary group is referent.

  • b Physically active enough to cause sweating or hard breathing.

  • c Numbers for analysis: parous, 2190; nulliparous, 204; for the three levels of body mass index: 836, 819, and 836.