Impact of Traditional Cigarette Smoking on Liver Structure and Function

Background: Cigarette smoking exposes the human body to a complex mixture of toxic and carcinogenic compounds that can exert widespread biological effects across different organ systems. From addictive responses and consequence maladaptive neuroendocrine responses, cigarette smoke delivers a variety of reactive oxygen species, polycyclic aromatic hydrocarbons, nitrosamines, and heavy metals that collectively contribute to oxidative stress, inflammation, endothelial dysfunction, and metabolic disruption. The liver, as the primary organ responsible for xenobiotic metabolism, plays a central role in processing these harmful substances and is therefore uniquely susceptible to their effects. This narrative review will aim to provide an overview of the current evidence of cigarette smoking effects on hepatic structure and function and discuss clinical implications. Methods: This narrative review synthesizes evidence from in vitro studies, animal models, and human clinical research examining the effects of cigarette smoking on liver biology. Mechanistic pathways of injury, metabolic and vascular alterations, and clinical consequences for liver disease were considered. Results: Smoking influences hepatic function both directly—through biotransformation pathways generating reactive intermediates—and indirectly via vascular impairment, immune modulation, hormonal alterations, and changes in lipid and glucose metabolism. Emerging evidence indicates that cigarette smoking contributes to hepatic steatosis, accelerates fibrosis progression, worsens outcomes in viral and alcohol-related liver disease, and increases the risk of hepatocellular carcinoma. Conclusions: Cigarette smoking exerts multifaceted deleterious effects on the liver. Recognition of smoking as a modifiable risk factor for liver-related morbidity underscores the importance of smoking cessation in patients with or at risk for liver disease and highlights implications for research and clinical practice.