Prevalence of sleepiness in a group of Brazilian lorry drivers

To determine the prevalence of sleepiness in a group of Brazilian lorry drivers.

Cross-sectional study.

This study used a self-administrated questionnaire and the Epworth Sleepiness Scale (ESS). The questionnaire included questions regarding demographic features, professional data, sleep habits, night-time symptoms, excessive daytime sleepiness and history of previous automobile accidents.

Four hundred and thirty-eight male drivers, aged 34.2+/-9.5 years (mean+/-SD), were included in the study. The mean number of hours spent driving each day was 9.2+/-2.6h, compared with 4.5+/-2.3h for the night shift. The median distance covered weekly was 1,200 km (range 70-6,000 km). The most common sleep complaints were insomnia (26.6%), loud snoring (45%) and witnessed apnoea (7.6%). Eighty-six of 392 (22%) drivers reported falling asleep while driving, and 11 (2.8%) subjects indicated falling asleep daily or almost daily. One hundred and seventy-one drivers (39%) had been involved in a traffic accident, and 21 of 128 drivers (16.4%) indicated sleepiness as a possible contributing factor. The ESS was higher than 10 points in 120 (28%) of the interviewees.

Sleepiness is a prevailing symptom in lorry drivers and is probably related to accidents.