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

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.

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.

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).

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.