LEP and breast carcinoma: A previous meta-analysis reported that circulating leptin concentrations in breast cancer survivors were significantly reduced after exercise interventions (weighted mean difference (WMD): −5.7; 95% confidence interval (CI): −11.0, −0.3) but not in combined exercise and weight loss interventions (WMD: −3.0; 95% CI: −7.0, 1.1) [25].