LEP and breast cancer: The mean leptin levels were significantly higher in the pre-menopausal BC cases (SMD = 0.28, 95% CI = 0.07–0.48, P = .008) or post-menopausal BC cases (SMD = 0.63, 95% CI = 0.38–0.88, P <.0001) than these in controls (Fig. 5).