Table 3

Joint effect of blood C-peptide concentration and BMI or WHR on the risk of breast cancer from the Shanghai Breast Cancer Study, 1996–1998

C-peptide levels (ng/ml)WHR < 0.8 (median)WHR ≥ 0.8 (median)
Case/controlOR (95% CI)aCase/controlOR (95% CI)a
≤0.7019/311.0 (referent)10/151.3 (0.4–3.9)
0.71–1.0717/221.6 (0.6–4.0)28/272.7 (1.0–7.3)
>1.0721/173.0 (1.1–8.5)48/313.9 (1.6–9.8)
BMI < 22.8 (median)BMI ≥ 22.8 (median)
Case/controlOR (95% CI)aCase/controlOR (95% CI)a
≤0.7019/381.0 (referent)10/83.0 (0.8–11.4)
0.71–1.0718/222.3 (0.9–6.2)27/272.6 (1.0–6.3)
>1.0717/123.7 (1.3–10.1)52/364.1 (1.7–9.8)
  • a All ORs are adjusted for age at the first live birth.