Abstract
BACKGROUND: α-Klotho is a molecule associated with aging and several diseases. Previous studies have reported decreased levels of serum α-Klotho (SαKl) in smokers compared to never smokers. Interestingly, we also found the SαKl level could partly recover in those who quit smoking. The objective of this study was to investigate SαKl levels in the US population who quit smoking for a certain period. METHODS: A total of 9268 participants, ranging in age from 40 to 79 years were enrolled in this cross-sectional study, 37.04 % were identified as former smoker. Data from the NHANES conducted between 2007 and 2016 were utilized for analysis. The association between the period of smoking cessation and SαKl levels was evaluated through multivariate linear regression models. Additionally, a detailed analysis stratified by key clinical factors was performed. RESULTS: The mean level of SαKl among the former smoker was 827.41 pg/mL. After full adjustment, the SαKl level increased over time after smoking cessation, with an increase of 1.20 pg/ml per year of abstinence (P = 0.005). The linear correlation persists regardless of the duration of the smoking habit before quitting. In the stratified analysis, a positive correlation was observed between duration of smoking cessation and SαKl levels in individuals aged 60-79 years, females, normal weight individuals, those involved in moderate or vigorous physical activity, and those with a history of cancer (all P<0.05). CONCLUSION: This study showed a positive association between the duration of smoking cessation and SαKl levels in former smokers. Prolonged abstinence may contribute to increased SαKl levels which may protect people against aging-related diseases.