Shift Work as a Risk Factor for Poor Sleep Quality and Daytime Sleepiness in Khorasan Railway Personnel in Iran

Background: Shift work disrupts the sleep rhythm and leads to daily sleepiness and physical and mental complications. Objectives: This study aimed to investigate the predictive role of shift work in poor sleep quality and daytime sleepiness in railway personnel. Methods: This descriptive-analytical and cross-sectional study was conducted on the employees of the Khorasan railway in Iran in 2021, 450 individuals of whom were selected as a sample using the census sampling method. The data collection method was through a checklist containing demographic information and related factors (e.g., employment history) and through a physician to evaluate underlying diseases, body mass index (BMI), smoking and use of substances (past medical history), and completion of standard questionnaires, including the Pittsburgh Sleep Quality Index (PSQI), Karolinska Sleepiness Scale (KSS), and STOP-BANG questionnaire. The data were analyzed using the t-test and simultaneous multivariate regression analysis by SPSS software (version 24). Results: Out of 450 employees, 144 (32%) and 306 (68%) subjects were day workers and shift workers, respectively. The average age of the participants was 40 ± 5.97 years. A significant difference was observed between the BMI with PSQI, KSS, and STOP-BANG scores (P = 0.001). Additionally, binary logistic regression analysis showed that shift work had a significant effect as a risk factor on both PSQI scores (CR = 1.25, 95% CI: 1.16-1.32, P = 0.001) and KSS scores (CR = 1.43, 95% CI: 1.29 - 1.59, P = 0.001). Conclusions: Shift work could increase the amount of sleepiness during work in personnel as the main cause, along with other effective factors, such as personal and occupational characteristics.