Heavy Metals, Trace Elements, and Smoking Biomarkers in Venous and Cupping Blood Before and After Wet Cupping Therapy

Wet cupping therapy (Hijama) is increasingly examined using biochemical endpoints, yet its toxic-metal and trace-element profile in smokers remains poorly defined. This paired three-sample study investigated serum toxic metals, essential trace elements, metal-derived indices, and smoking-exposure biomarkers in 60 adult male smokers undergoing wet cupping. Cd, Co, Cu, Fe, Hg, Ni, Pb, and Zn were measured by inductively coupled plasma optical emission spectroscopy (ICP-OES), while nicotine and cotinine were assessed by reversed-phase high-performance liquid chromatography with diode-array detection (RP-HPLC-DAD) in baseline venous blood, cupping blood, and venous blood collected 9-10 days after wet cupping. Co and Hg were below the analytical reporting threshold. Cupping blood showed a distinct elemental profile, with higher Cd, Cu, Fe, Ni, and Pb and lower Zn than baseline venous blood (all p < .001). After 9-10 days, venous Cd, Cu, Fe, Ni, and Pb decreased significantly, whereas venous Zn increased significantly (all p < .001). These venous changes were accompanied by reductions in toxic metal burden index (TMBI), TMBI-Zn, Cu/Zn, and Cd/Zn, together with an increase in Zn/Cu. Nicotine and cotinine significantly decreased at follow-up; however, baseline nicotine and cotinine were not significantly associated with measured metals. In contrast, self-reported cigarette consumption was positively associated with baseline Ni, Cu, and Cd and inversely associated with Zn, with these relationships persisting after adjustment for age, BMI, nicotine, and cotinine. These findings support a distinct cupping-blood elemental matrix and an exploratory association pattern between self-reported cigarette consumption and selected metal/Zn biomarkers.