INTRODUCTION Smoking tobacco results in the death of more than 8 million people every year. Our study aims to explore a new approach for smoking cessation by analyzing body composition differences between smokers and non-smokers, focusing on potential variations in biological and chronological ages.METHODS A cross-sectional study was conducted in 2019 at the Special Hospital for Medical Rehabilitation in Croatia. It included 164 subjects, 81 smokers and 83 non-smokers, aged 40-65 years. This study was part of a two-year investigation on locomotor parameter changes as early COPD predictors. Measurements encompassed body parameters, spirometry tests, and body composition. Spirometry was done using the Flowscreen Pro device, and the FEV1/FVC ratio determined lung function. The GAIA 359 PLUS device assessed body composition and estimated biological age. Exclusion criteria applied to specific medical conditions and recent surgeries.RESULTS Smokers had a slightly higher percentage of fat tissue than non-smokers (median=27%, IQR: 24-31) compared to non-smokers (median=25%, IQR: 22-28, p<0.001). The difference in the Gaia estimated age and the actual age of the subjects was significantly higher in the group of smokers (median=2, IQR: 0-3) compared to non-smokers (median=0 IQR:-2-2, p=0.003), but they did not differ in muscle tissue, weight or the proportion of trunk adipose tissue.CONCLUSIONS Our study revealed that smokers exhibit higher fat tissue percentages and a higher estimated biological age relative to non-smokers. These findings underscore the established health hazards of smoking and the imperative for smoking cessation in mitigating these adverse effects.