BACKGROUND: Sinus barotraumas are a common condition in aviation medicine, sometimes compromising flight safety and even permanently grounding aircrew. Considering this and the ever-increasing amount of commercial aviation, a thorough examination is required.METHODS: In this survey study, an anonymous, electronic questionnaire was distributed to commercial aircrew of the three major commercial airlines operating in Finland (N 3799), covering 93% of the target population (i.e., all commercial aircrew operating in Finland, N 4083). Primary outcomes were self-reported prevalence, clinical characteristics, and health and occupational effects of sinus barotraumas in flight. Secondary outcomes were adjusted odds ratios (OR) for frequency of sinus barotraumas with respect to possible risk factors.RESULTS: Response rate was 47% (N 1789/3799), with 61% (N 1088) of the respondents having experienced sinus barotraumas in flight. Of those affected, 59% had used medications, 18% had undergone surgical procedures, and 53% had been on sick leave due to sinus barotraumas (38% during the last year) in flight. Factors associated with sinus barotraumas were female sex [OR, 2.47; 95% confidence interval (CI) 1.354.50] and a high number of upper respiratory tract infections (3 vs. <3 URTIs/yr: OR, 3.61; 95% CI 2.654.93).CONCLUSION: Sinus barotraumas were reported by 61 of commercial aircrew. They caused an increased need for medications, otorhinolaryngology-related surgical procedures, and sickness absence from flight duty. The possible risk factors were female sex and a high number of URTIs/yr.Lindfors OH, Ketola KS, Klockars TK, Leino TK, Sinkkonen ST. Sinus barotraumas in commercial aircrew. Aerosp Med Hum Perform. 2021; 92(11):857-863.