Tobacco Use and Second-Hand Smoke Exposure Among Athletes; Assessment by Urine Cotinine Level and Exhaled Carbon Monoxide: A Cross-Sectional Study.

Background and Objectives: Tobacco use and exposure to tobacco products remain a major public health challenge, even among athletes. This study aimed to evaluate tobacco use and second-hand smoke exposure in athletes through urinary cotinine levels and exhaled air carbon monoxide (CO) measurements. Materials and Methods: This cross-sectional study included licensed athletes who visited the sports medicine outpatient clinic of a tertiary hospital. Participants completed an electronic questionnaire on smoking habits and second-hand smoke exposure. Urine samples were analysed for cotinine levels, while CO levels were measured in exhaled breath. Results: A total of 421 athletes participated (57.8% male, median age: 18 years). Tobacco use was reported by 29.9% (n = 126) of participants. Median urinary cotinine levels were 22.9 ng/mL among daily tobacco users and 17.4 ng/mL among athletes exposed daily to second-hand smoke, with a statistically significant difference between exposure levels (p < 0.05). The optimal cut-off value for detecting second-hand smoke exposure was identified as 12.5 ng/mL. Median exhaled air CO levels were 5 ppm in daily tobacco users. Conclusions: This study demonstrates that tobacco use prevalence among athletes mirrors Türkiye's national rates. Despite legal measures to curb tobacco use, direct use and second-hand smoke exposure remain pressing issues among athletes.