Aim The aim of the study was to assess the impact of COVID-19 pandemic on patterns of cigarette, hookah and marijuana consumption among undergraduate students of Bosnia and Herzegovina. Methods The first part of the double cross-sectional study was conducted among undergraduate students of the University of Sarajevo from 22nd to 26th January 2020, prior to the first COVID-19 case in the country (study period 1), and the second part from March 25th to August 26th 2021, during the third wave of COVID- 19 outbreak (study period 2). Results The majority of the 1,230 respondents were women (N1 70.9%, N2 70.1%), pursuing medical sciences (N1 60.0%, N2 55.0%), in their 3rd year of study (N1 26.3%, N2 26.7%), and living in urban environment (N1 84.9%, N2 86.4%). Similar proportion of cigarette smokers (N1 38.5%, N2 39.2%), and smaller, similar portions of hookah smokers (N1 19.3%, N2 21.1%) were classified in both study periods, while the smallest portion of marijuana smokers (N2 8.0%) was classified during COVID-19. Similar number of cigarettes per day, types of cigarettes consumed and consumption frequency in the last 30 days, with the similar independent predictors of cigarette consumption (being woman and living in rural environment associated with decreased risk, and age older than 22 associated with increased risk) were identified both before and during COVID-19 pandemic. Compared to before COVID-19 pandemic, increased trends in intentions (73.6% vs. 81.2%) and attempts (51.9% vs. 75.1%) to smoking cessation among cigarette smokers, but decreased determination not to smoke in the coming year among cigarette non-smokers (N1 72.2%, N2 51.6%) and decreased awareness of smoking harmfulness among both cigarette smokers (N1 68.0%, N2 46.5%) and especially cigarette nonsmokers (N1 60.9%, N2 22.9%) were seen during COVID-19 pandemic. Also, risky behavior among hookah smokers was evident during COVID-19 pandemic. Conclusions COVID-19 pandemic seemed to positively affect intentions and attempts to smoking cessation among cigarette smokers while negatively affecting attitudes towards cigarette smoking among cigarette non-smokers.

Objectives To evaluate the sleep patterns among young West Balkan adults during the third wave of the COVID-19 pandemic. Design and setting Cross-sectional study conducted using an anonymous online questionnaire based on established sleep questionnaires Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI) (February–August 2021). Participants Young adults of Bosnia and Herzegovina, Croatia and Serbia. Results Of 1058 subjects, mean age was 28.19±9.29 years; majority were women (81.4%) and students (61.9%). Compared with before the pandemic, 528 subjects (49.9%) reported a change in sleeping patterns during the pandemic, with 47.3% subjects reporting sleeping less. Mean sleeping duration during the COVID-19 pandemic was 7.71±2.14 hours with median sleep latency of 20 (10.0–30.0) min. Only 91 (8.6%) subjects reported consuming sleeping medications. Of all, 574 (54.2%) subjects had ISI score >7, with majority (71.2%) having subthreshold insomnia, and 618 (58.4%) PSQI score ≥5, thus indicating poor sleep quality. Of 656 (62.0%) tested subjects, 464 (43.9%) were COVID-19 positive (both symptomatic and asymptomatic) who were 48.8%, next to women (70%), more likely to have insomnia symptoms; and 66.9% were more likely to have poor sleep quality. Subjects using sleep medication were 44 times, and subjects being positive to ISI 15.36 times more likely to have poor sleep quality. In contrast, being a student was a negative independent predictor for both insomnia symptoms and poor sleep quality, and mental labour and not working were negative independent predictors for insomnia symptoms. Conclusions During the third wave of the pandemic, sleep patterns were impaired in about half of young West Balkan adults, with COVID-19-positive subjects and being women as positive independent predictors and being a student as negative independent predictor of impaired sleep pattern. Due to its importance in long-term health outcomes, sleep quality in young adults, especially COVID-19-positive ones, should be thoroughly assessed.

Background Bosnia and Herzegovina hasn't still developed and started any vaccination programs to contain the current COVID-19 outbreak and prevent further spreading and death from this disease. The aim of this study was to assess current knowledge, attitudes and practices towards COVID-19 vaccination during the third wave of the outbreak when the healthcare system is facing a collapse and to create a paradigm for developing vaccination programs in the country. Methods This cross-sectional study was conducted by an anonymous online questionnaire based on a Congo study and Center for Disease Control and Prevention facts regarding COVID-19 vaccination during the third wave of the COVID-19 outbreak in the country. Results In total, 570 subjects, mostly female 474 (83.1%), with a high school degree or lower 230 (40.3%), married 305 (53.5%), engaged in intellectual labor 302 (53.0%), from urban environment 531 (93.1%) and with a mean age of 35.28±11.35, were included in the study. The mean COVID-19 vaccination knowledge test score was 11.29±1.91. Being single (OR= 1.88, 95% 1.20-2.94) or in a relationship (OR=1.87, 95% 1.12-3.11), being engaged in intellectual labor (OR=1.59, 95% CI 1.06-2.37) and having a Master's degree or higher (OR=1.65, 95% CI 1.10-2.46) were associated with higher knowledge test scores. Only 264 (46.3%) subjects agreed that COVID-19 vaccination programs will prevail in a battle versus COVID-19 and only 36 (6.3%) were currently vaccinated against COVID-19. Higher knowledge regarding COVID-19 and its vaccination was determined as an independent predictor for vaccinating itself against COVID-19 (OR=23.09, 95% CI 11.94-44.68), as well as respecting socio-epidemiological measures such as avoidance of crowded places (OR=2.07, 95% CI 1.28-3.35) and wearing face mask (OR=6.95, 95% CI 2.07-23.29). Conclusions Our study shows that Bosnia and Herzegovina population has poor knowledge, relatively pessimistic attitudes and a very low vaccinal rate against COVID-19 during the third wave of the outbreak which promotes COVID-19 vaccination hesitancy and further COVID-19 spreading and death toll. By activating proper socioepidemiological measures and educating population about COVID-19 and COVID- 19 vaccination, as well as vaccination against COVID-19, the current situation could be changed.

BACKGROUND Indoor air quality (IAQ) in classrooms affects children's health and academic perfor-mance. The aim of this pilot study was to determine IAQ in elementary schools different in their inter-nal and external characteristics, in settings of COVID-19 epidemics. METHODS IAQ parameters: fine particulate matter (PM2,5) mass concentration, CO2 concentration, tempera-ture and relative humidity were measured in parallel in four elementary schools/classrooms during October (non-heating season) and four months (including holiday in January) of heating season. IAQ parameters were measured in settings of anti-epidemic restrictions (≤13 students in classroom, frequent ventilation). RESULTS During October, except in one school, PM2,5 concentrations were below the upper recommended value (25 μg/m³), but started rising in all schools in the heating season. The highest concentrations of PM2,5 were registered in two schools with closed or shortly opened windows. CO2 concentrations were mostly in the recommended range (up to 1000ppm) except in the school with constantly closed windows and in three schools in February when concentrations were higher. Except in one, the same school, and in January, both temperature and relative humidity were out of the recommended range (24,0-27,0°C in non-heating; 20,0-24,0°C in heating season; and 45-55%), with temperature mainly above and relative humidity mainly below it in three schools. The largest deviation in temperature and relative humidity were registered in urban schools. Registered differ-ences may be explained by different internal and external characteristics. CONCLUSION Despite anti-epidemic restrictions, most of the measured IAQ parameters were out of the recom-mended values in heating season. In addition, further deterioration of IAQ could be expected if all students had been presented in the classroom. Finally, to assure a healthy school environment in heating season, further optimisation of both indoor and outdoor conditions is needed in both pandemic and non-pandemic settings.