Table 1

Comparison of cases and controls by education levels and major breast cancer risk factors, Shanghai Breast Cancer Study, 1996–98

No. of Cases (%)aNo. of Controls (%)aOR (95% CI)
Education levels
 <Middle school13.015.91.0 (reference)
 Middle and high school70.772.01.3 (0.7–2.4)
 >High school16.312.21.7 (0.8–3.5)
First-degree relative with breast cancer
 No96.398.01.0 (reference)
 Yes3.72.01.8 (0.6–5.4)
Ever diagnosed with breast fibroadenoma
 No93.595.91.0 (reference)
 Yes6.54.11.6 (0.7–3.5)
Waist-to-hip ratio
 <0.7510.614.61.0 (reference)
 0.75–0.8466.769.11.4 (0.8–2.4)
 ≥0.8522.816.32.2 (1.1–4.4)
Body mass index
 <2010.616.31.0 (reference)
 20–2458.954.51.7 (1.0–2.9)
 ≥2530.529.31.6 (0.9–3.0)
Age at menarche (yr)
 <139.810.21.0 (reference)
 13–1680.574.01.1 (0.6–2.0)
 ≥179.815.90.6 (0.3–1.4)
Age at menopause (yr)b
 <459.916.81.0 (reference)
 45–5481.276.82.4 (0.9–6.3)
 ≥558.96.33.2 (0.8–12.7)
Age at first live birth (yr)c
 <2527.729.11.0 (reference)
 25–3466.568.81.0 (0.7–1.6)
 ≥355.82.12.9 (1.0–8.3)
  • a Unless otherwise specified, data are from 246 case-control pairs.

  • b Among postmenopausal women.

  • c Among parous women.