Table 4.

Covariate-adjusteda ORs and 95% CIs of breast cancer by leptin level by tumor characteristics among premenopausal women at blood collection in the Nurses' Health Study II

 Leptin concentrations, ng/mL
≤26.69≥26.7Pheterogeneityb
ER/PR status
 ER+1.00 (reference)0.99 (0.58–1.71)0.12
 Cases13040
 ER−1.00 (reference)0.38 (0.12–1.18)
 Cases377
 PR+1.00 (reference)1.08 (0.62–1.87)0.009
 Cases11340
 PR−1.00 (reference)0.21 (0.06–0.66)
 Cases555
In situ vs. invasive
In situ1.00 (reference)0.42 (0.19–0.91)0.14
 Cases8313
 Invasive1.00 (reference)0.80 (0.49–1.31)
 Cases17548

Abbreviation: MET, metabolic equivalent.

  • aPolytomous logistic regression adjusted for matching factors, age at menarche (<12, 12, 13, >14), parity/age at first birth (nulliparous, age at first birth <25 years/1–4 children, age at first birth 25–29 years/1–4 children, age at first birth ≥30 years/1–4 children, age at first birth <25/≥5 children, age at first birth ≥25/≥5 children), family history of breast cancer (yes/no), history of benign breast disease (yes/no), physical activity (<3, 3–<9, 9–<18, 18–<27, 27–<42, and ≥42 MET/wk), and BMI at blood draw (continuous).

  • bDetermined using polytomous logistic regression.