Objective: The objective of this study is to identify the role of working conditions as predictors of sleepiness while driving among truck drivers. Methods: This was a cross-sectional study carried out among truck drivers who transported grains to Paranaguá Port, Paraná, Brazil. The truck drivers were interviewed and completed a self-administered questionnaire to collect data on sociodemographic and behavioral variables, working conditions, consumption of illicit psychoactive substances, and sleep patterns. Drivers were considered to be sleepy while driving if they reported a medium or high probability of napping while driving at night, during the daytime, or while stopped in traffic. The statistical analysis used logistic regression models progressively adjusted for age, behavioral variables, sleep duration, and other working conditions. Results: In total, 670 male drivers, with a mean age of 41.9 (±11.1) years, were enrolled. The prevalence of sleepiness while driving was 31.5%. After model adjustments, the following working conditions were associated with sleepiness while driving: Distance from the last shipment of more than 1,000 km (odds ratio [OR] = 1.54; 95% confidence interval [CI], 1.07-2.23) and a formal labor contract with a productivity-based salary (OR = 2.65; 95% CI, 1.86-3.78). Consumption of illicit psychoactive substances (OR = 1.99; 95% CI, 1.14-3.47) was also associated with sleepiness while driving. Conclusions: Distance traveled and a formal labor contract with productivity-based earnings were the working conditions associated with sleepiness while driving, regardless of other working or behavioral characteristics, age, consumption of illicit psychoactive substances, and sleep duration.
Keywords: Disorders of excessive somnolence; traffic accidents; truck drivers; working conditions.