How many truck drivers would have sleep disorders? : Investigation on lifestyle and stress on insomnia among Japanese male truck drivers.

Abstract

Objectives: This study aimed to investigate how many drivers would have sleep disorders and what factors would be most associated with chronic insomnia symptoms.

Methods: A cross-sectional study of 505 truck drivers in Akita prefecture was conducted using a self-administered questionnaire and health checkup data. We defined insomnia based on the International Classification of Sleep Disorders, 3rd edition (ICSD-3), sleep apnea syndrome (SAS) with a simple four-variable screening tool, and restless legs syndrome (RLS) with RLS/Willis-Ekbom disease diagnostic criteria. Investigated factors included sleep duration, driving characteristics, caffeine types (foods and beverage) and amounts, caffeine intake timing, state-trait anxiety inventory (STAI), individual stress, and other covariates.

Results: The prevalence of suspected SAS was 23.2% (n = 154), and that of RLS was 0.8% (n = 5). After excluding those, chronic insomnia symptoms were present in 36/505 drivers (7.1%). After adjusting for covariates, a logistic model demonstrated that drinking habits (Odds ratio, OR 6.21, 95% Confidence Interval, CI:1.07-35.8), caffeine intake before sleep (OR 2.65, 95% CI:1.09-6.45), sleep duration on days off (OR 1.44, 95% CI: 1.01-2.05), and STAI score (OR 12.8, 95% CI: 2.53-64.2) were significantly associated with chronic insomnia symptoms. STAI was significantly positively correlated with individual stress, such as family worries (r = 0.22), relationships with non-partners (r = 0.28), and health (r = 0.23).

Conclusions: Our study revealed that one fourth of male truck drivers had sleep disorders that require further medical evaluation. For male truck drivers, a lifestyle modification and stress relief may be a key to address insomnia.