Safety incidents and obstructive sleep apnoea in railway workers

Current evidence is lacking to justify more stringent screening for obstructive sleep apnoea (OSA) in the rail industry. Population-based studies indicate a complex association between body mass index, age, apnoea-hypopnoea index and vehicle crash risk.

To study the association between OSA severity and the occurrence of safety incidents in safety-critical rail workers with a confirmed diagnosis of OSA, and to identify if OSA treatment is associated with the occurrence of fewer safety incidents.

A retrospective medical file audit was conducted on railway workers attending health assessments between 2016 and 2018, who met the criteria to be referred for sleep studies. The association between OSA severity, treatment and the number of incidents in the 3 years before their health assessment appointment was explored using a Poisson log-linear regression.

A substantial proportion (44%, 274/630) of railway workers with confirmed OSA had at least one incident in the 3 years prior to appointment. The odds of an incident were significantly reduced in those with moderate OSA compared with severe OSA (odds ratio [OR] 0.79, 95% confidence interval [CI] 0.64-0.98), but not those with mild OSA (OR 0.97, 95% CI 0.76-1.24). There was a statistically significant relationship between combined OSA severity and treatment status, where the likelihood of an incident increased in those with severe untreated OSA compared with those receiving treatment (OR 1.75, 95% CI 1.16-2.64).

Our results suggest that more stringent screening to identify severe OSA early, and close surveillance of treatment of those with severe OSA, should be considered.