Serum nicotine metabolite profiles and their association with hematological, biochemical, and cardiovascular parameters in smokers

Abstract Objectives Cigarette smoking remains a major contributor to preventable cardiovascular morbidity and mortality. While the Fagerström Test for Nicotine Dependence (FTND) evaluates behavioral addiction, objective biochemical markers linking dependence severity to cardiovascular risk remain limited. This study investigated associations between serum nicotine metabolites, FTND, and Framingham Risk Score (FRS) in male smokers. Methods A cross-sectional study was performed in 104 male smokers aged 18–65 years. Nicotine dependence was assessed using the FTND. Serum nicotine, cotinine, norcotinine, and 3-hydroxycotinine levels were quantified by a validated LC–MS/MS method. Cardiovascular risk was estimated using the FRS, and correlations among metabolites, FTND scores, and smoking duration (pack-years) were analyzed. Results Nicotine metabolite concentrations across FTND dependence categories demonstrated increasing trends for cotinine and norcotinine. However, after adjustment for multiple comparisons using the Benjamini–Hochberg false discovery rate, only norcotinine levels differed significantly between FTND groups (q=0.030), with higher concentrations observed in individuals with greater dependence severity. Smoking duration expressed as pack-years showed a positive association with serum norcotinine concentrations, and this relationship remained statistically significant following FDR correction (r=0.327, q=0.008). Conclusions Norcotinine emerged as the most robust biochemical marker of nicotine dependence and cumulative tobacco exposure, linking behavioral addiction severity with long-term metabolic burden. The absence of associations between nicotine metabolites and FRS highlights the limited capacity of single time-point exposure markers to reflect multifactorial cardiovascular risk. These findings support the need for integrated behavioral and metabolic approaches in addiction assessment.