LEP and breast cancer: In the model including only matching factors (Table 2), no significant associations were observed for interleukins, TNF-α, and IFN-γ with breast cancer risk, while leptin and leptin/adiponectin ratio showed significant negative associations (leptin: ORper SD increment (95% CI) = 0.76 (0.66–0.87), ORQ4vsQ1 = 0.48 (0.33–0.70), P-trend < 0.001; leptin/adiponectin ratio: ORper SD increment = 0.75 (0.65–0.86), ORQ4vsQ1 = 0.53 (0.36–0.79), P-trend < 0.001).