Leptin, leptin-to-adiponectin ratio and CRP were inversely associated with breast cancer risk in premenopausal women [OR1SD = 0.89 (0.77–1.03), OR1SD = 0.88 (0.76–1.01) and OR1SD = 0.87 (0.75–1.01), respectively] but positively associated with breast cancer risk in postmenopausal women [OR1SD = 1.16 (1.05–1.29), OR1SD = 1.11 (1.01–1.23), OR1SD = 1.10 (0.99–1.22), respectively]. This evidence concerns the gene LEP and breast carcinoma.