Additive interactions of sleep disorders, insufficient sleep, and shift work on road and workplace safety incidents: A sufficient cause approach with overlap weights

Background: Behavioural and biological factors impacting healthy sleep can influence road and workplace safety. This study investigated the additive interactions of sleep-disrupting factors (sleep disorders, insufficient sleep, and shift work) on road and workplace safety in young adults (22 years) from the Raine Study. 

Methods: Employed participants (n = 439, median age 22.0 years, IQR 21.6–22.3) were assessed for common sleep disorders (obstructive sleep apnoea, insomnia, restless legs syndrome). They provided information on shift work status, habitual sleep duration (insufficient sleep <7 h), and self-reported road and work incidents. A sufficient cause approach with inverse probability of overlap weights and logistic regression was used to study additive interactions. 

Results: Sleepiness while driving was reported by 16 % and while at work by 11 % of participants. Insufficient sleep alone increased the odds of falling asleep while driving (OR 2.29; 95 % CI 1.17, 4.32). Three sleep-disrupting factors additively increased the risk of near-miss road incidents (β, 1.40 > 0). Sleep disorders with shift work was associated with the highest risk of falling asleep at work (relative excess risk due to interaction, RERI; 4.86; 95 % CI, 2.9, 6.81). 

Conclusion: The combined burden of multiple sleep-disrupting factors including sleep disorders, insufficient sleep and shift work, is associated with an increased risk of near-miss road incidents and falling asleep at work. Given that sleepiness, both on the road and in the workplace, is common in young adults, there is a need for greater awareness and intervention to address the associated risks.