The impact of smoking on estimated biological age and body fat composition: A cross-sectional study.

"CONFLICTS OF INTEREST The authors have completed and submitted the ICMJE Form for Disclosure of Potential Conflicts of Interest and none was reported."

"FUNDING There was no source of funding for this research."

"A cross-sectional study was conducted on patients undergoing medical rehabilitation or medically programmed vacation at the Special Hospital for Medical Rehabilitation in Daruvarske Toplice, Croatia in 2019. The patients were part of another, large two-year study that investigated changes in locomotor parameters in smokers as an early predictor for the development of COPD. The sample included a total of 164 subjects, 81 smokers and 83 non-smokers. The age of the subjects was between 40 and 65 years, and all patients voluntarily signed an informed consent to participate in the study. The Ethical Committee of the Special Hospital for Medical Rehabilitation Daruvarske Toplice gave consent to conduct a larger study registered at Clinicaltrials.gov under the study’s ID NCT04643600, of which this study is a part. Body mass, height, BMI and waist circumference were measured for all patients. All patients underwent spirometry, and patients whose Tiffeneau–Pinelli index (the ratio of FEV1 to FVC) was lower than 70%, i.e. those with a diagnosis of COPD, were excluded from the study. Excluded from the sample were patients suffering from inflammatory rheumatic diseases, malignant diseases, acute and severe heart or lung diseases, unregulated hypertension, those who underwent a major surgical procedure in the past year, as well as patients with implanted hip, knee or ankle prostheses."