Featured Articles from January 2014

Excessive Daytime Sleepiness Increases the Risk of Motor Vehicle Crash in Obstructive Sleep Apnea

A very interesting retrospective case-series observational study conducted using data from the West Australian Sleep Health Study at a tertiary hospital-based sleep clinic. It describe the incidence rate of motor vehicle crashes (MVCs) in patients with obstructive sleep apnea (OSA); and investigates MVC risk factors in OSA patients. 2673 patients were assessed for suspected sleep disordered breathing. Questionnaire data were collected including age, sex, years of driving, near-misses and MVCs, sleepiness, and consumption of alcohol and caffeinated drinks and an overnight laboratory-based polysomnography was performed.

The authors show that the crash rate was 0.06 MVC/person-year compared with the general community crash rate of 0.02 MVC/person-year. They concluded that untreated OSA was associated with an increased risk of near-misses in men and women and an increased risk of MVCs in very sleepy men. There was a strong association between excessive daytime sleepiness and increased report of near-misses. The data supports the observation that it is those patients with increased sleepiness regardless of OSA severity who are most at risk.


Nocturnal Intermittent Hypoxia is Independently Associated With Pain in Subjects Suffering From Sleep-Disordered Breathing

Obstructive sleep apnea is characterized by both sleep fragmentation and nocturnal recurrent hypoxemia. Experimental fragmentation or deprivation of sleep enhances sensitivity to pain, promotes inflammation, and advances spontaneous pain in healthy humans. The authors hypothesized that nocturnal hypoxemia would be associated with pain reports in subjects suffering from sleep-disordered breathing, independently of sleep fragmentation and inflammation. They examined the association between arterial desaturation and four different types of pain, as well as their composite measure, sequentially adjusted for: clinical characteristics, sleep fragmentation and inflammation. Decreased minimum nocturnal arterial saturation increased the odds for morning headache, headache disrupting sleep, and chest pain while in bed. A decrease in the minimum nocturnal saturation from 92 to 75% approximately doubled the odds for pain. Furthermore, the authors identified that one single-nucleotide polymorphism for the α 1 chain of collagen type XI (COL11A1-rs1676486) gene was significantly associated with headache disrupting sleep, pain disrupting sleep, and pain composite.

The authors concluded that nocturnal arterial desaturation may be associated with an increased pain in subjects with sleep-disordered breathing, independently of sleep fragmentation and inflammation.