Assessment of circulating xenin as a potential metabolic biomarker in active smokers.

Abstract

Objectives: Xenin regulates appetite, motility, and metabolic homeostasis. As the link between smoking and xenin has not yet been sufficiently investigated, this study compared serum levels between smokers and non-smokers and evaluated their associations with metabolic, hematological, and tobacco-related parameters.

Methods: Utilizing a cross-sectional case-control framework, the present study evaluated a group of 128 subjects, comprising 66 smokers and 62 non-smokers. Serum xenin levels and clinical, metabolic, lipid, and hematological parameters were compared between groups. Subgroup analyses were performed according to sex, body mass index (BMI), and HOMA-IR categories. Correlation analyses were conducted to evaluate the associations of xenin with smoking exposure, nicotine dependence, and laboratory variables.

Results: Circulating xenin concentrations exhibited a significant elevation in the smoking group relative to non-smokers (p<0.001), and this difference persisted across the normal-weight (p=0.001), overweight (p=0.002), and obese (p<0.001) BMI categories, as well as in the HOMA-IR <2.5 (p=0.043) and HOMA-IR ≥2.5 (p<0.001) subgroups. In addition, xenin levels were positively correlated with pack-years, Fagerström score, HOMA-IR, and glucose (all p<0.05). Although xenin levels tended to increase with greater smoking exposure, the overall difference among smoking exposure groups was not statistically significant (p=0.151).

Conclusions: Serum xenin levels were significantly higher in smokers than in non-smokers, and this difference remained significant across BMI and HOMA-IR subgroups. These findings suggest that circulating xenin may be associated with smoking-related metabolic and neuroendocrine alterations and may have potential as a candidate biomarker. Further prospective studies are needed to validate its clinical relevance.