Accumulation of Heavy Metals in Smoker’s Blood and its Effects on Blood Biochemistry

Abstract

Background: Heavy metals such as cadmium (Cd) and lead (Pb) are toxic environmental contaminants that accumulate in the human body, particularly through cigarette smoking. Their presence disrupts normal blood biochemistry and may contribute to systemic and cardiovascular diseases. Despite global evidence, region-specific data on heavy metal exposure through smoking and its hematological effects remain limited in rural Pakistani populations. Objective: This study aimed to evaluate the impact of cigarette smoking on blood concentrations of Cd and Pb, and its association with haematological parameters including haemoglobin (Hb), red blood cells (RBCs), white blood cells (WBCs), and platelets in adult males. Methods: A prospective observational study was conducted on 60 male participants (n = 30 smokers; n = 30 non-smokers) aged ≥18 years from Samar Bagh, Dir Lower, Pakistan. Inclusion criteria encompassed self-reported smokers with ≥1 cigarette/day for ≥1 year, and healthy non-smokers. Blood samples were collected and analyzed using atomic absorption spectrophotometry for Cd and Pb concentrations, and automated hematology analyzers for Hb, RBCs, WBCs, and platelets. Ethical approval was obtained from the Institutional Review Board of University of Malakand (UOM/HEC/22/IRB-034) in accordance with the Helsinki Declaration. Data was analyzed using SPSS v27 with descriptive statistics and independent t-tests (p < 0.05). Results: Smokers showed significantly higher Cd (0.434 ± 0.510 mg/L vs 0.093 ± 0.055 mg/L, p = 0.00068) and Pb (11.668 ± 2.467 mg/L vs 7.199 ± 2.380 mg/L, p = 0.00019) levels than non-smokers. Hb and WBCs were elevated in smokers (15.52 ± 0.904 g/dL; 8.645 ± 1.45 ×10³/µL), while RBCs were lower (4.508 ± 0.317 ×10⁶/µL, p = 0.000244). Platelet counts showed variable trends with no significant difference. Conclusion: Cigarette smoking contributes to increased Cd and Pb accumulation and significantly alters key blood parameters, indicating elevated risks for cardiovascular and systemic diseases. These findings highlight the clinical relevance of blood monitoring in smokers and reinforce the importance of tobacco control interventions in public health.