LEP and metabolic syndrome: Five peer-reviewed papers which met our inclusion criteria examined associations between metal mixture exposures and risk of dyslipidemia [52,60] or lipid markers, such as triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), low-density lipoprotein cholesterol (LDL-C), and leptin levels [43,53,55,60].