Table 1

Comparison of breast cancer cases and controls by selected demographic and risk factors among postmenopausal Iowa women

All eligible subjectsStudy subjects
Cases (n = 456)Controls (n = 876)OR (95% CI)Cases (n = 176)Controls (n = 391)OR (95% CI)
Demographic and major risk factors
Age ≥ 64 yrs1712811.3 (1.0–1.6)541051.2 (0.8–1.8)
Education ≥ high school1923451.1 (0.9–1.4)911801.3 (0.9–1.8)
First-degree relatives with breast cancer75811.9 (1.4–2.7)29421.6 (1.0–2.7)
Waist to hip ratio ≥ 0.852163321.5 (1.2–1.9)781311.6 (1.1–2.3)
Body mass index ≥ 262694381.4 (1.1–1.8)941961.1 (0.8–1.6)
Menarche at ≤ 15 yrs4338281.1 (0.7–1.8)1703751.2 (0.5–3.1)
Menopause at ≥ 54 yrs711251.1 (0.8–1.5)28491.3 (0.8–2.2)
Live births ≤ 43095331.4 (1.1–1.7)1152141.6 (1.1–2.3)
First live birth ≥ 25 yrs1202281.0 (0.8–1.3)491051.1 (0.7–1.6)
Alcohol intake ≥ 2 g/day1232500.9 (0.7–1.2)561271.0 (0.7–1.4)
Meat doneness score
36241.0 (reference)a4151.0 (reference)
4522001.1 (0.4–2.8)341231.0 (0.3–3.3)
5711551.8 (0.7–4.7)46901.9 (0.6–6.1)
6571032.2 (0.9–5.7)43552.9 (0.9–9.5)
731801.6 (0.6–4.2)17521.2 (0.4–4.2)
813182.9 (0.9–9.1)792.9 (0.7–12.8)
912114.4 (1.3–14.7)755.3 (1.1–25.8)
Trend testP = 0.0003P = 0.0033
  • a Restricted to the 273 cases and 637 controls who completed the supplementary survey.