Sleep apnea among truck drivers

Why is there a higher rate of sleep apnea among truck drivers?

A conversation I had the other day got me thinking about sleep apnea among truck drivers. In the US, around 4% of adults have sleep apnea. Among truck drivers, it appears that the rate might be over 30%. That’s a pretty big disparity — so what would cause it?
The answer seems to lie within the demographics of truck drivers. About half of all truck drivers are over 45 years old – which is one of the highest risk groups for sleep apnea. Within the group of truck drivers, a study by Atlas Ergonomics (http://www.atlasergo.com/whitePapers/CommercialDrivingPartI_April2009.pdf) found that about 46% were classified as obese. The combination of these two factors alone greatly increases the occurrence of sleep apnea. This would partly explain such an over representation. However, it also raises the question of why this demographic is itself over represented within the population of truck drivers.
Let’s look a bit at how drivers have been recruited and hired over the last twenty years – before our current economic downturn.
For many years, there has been the myth of the shortage of qualified truck drivers. "Wait a minute" you might say. "If trucking companies don’t have enough drivers to fill their trucks, then the shortage isn’t a myth". That happens to be correct, at least as far as it goes. While there might not be enough drivers in trucks, it means there’s only a shortage of people willing to put up with the hours and working conditions for the wages being offered.
One of the toughest things about trucking is being away from home for extended periods of time, especially if you have young children. By the time drivers are in their mid-forties and beyond, their children are either grown and gone, or pretty close to it, which largely eliminates that as a constraint.
For many others, truck driving is pretty much the job of last resort. Try finding a job when you’re past 40 that doesn’t involve the phrase "You want fries with that?" and you’ll see what I mean.
Next, there’s the issue of sleep apnea itself. Sufferers are likely to be among the most overweight and least productive employees — and therefore the least likely to be hired, and the most likely to be laid off or fired — which pushes them toward that job of last resort.
You might then ask "if a truck driver has sleep apnea to begin with, how do they get away with it?". The answer to that is pretty simple — naps. I don’t know of any other job where employees are actually encouraged to stop work for a snooze break.
There’s been a great deal of talk about relationship between sleep apnea and truck crashes. An article at http://www.sciencedaily.com/releases/2007/05/070520130053.htm suggests that drivers with sleep apnea are twice as likely to crash, and 3 to 5 times as likely to have a severe crash.
Screening truck drivers for sleep apnea is a good idea (and one which some companies are already doing), and results so far have shown a positive impact on crash rates and severity, but I’m not sure if screening for sleep apnea alone really goes far enough. We need to remember that there are a lot of factors in play when it comes to truck driver fatigue. Even a driver well within the DOT hours of service limits can potentially be dangerously fatigued. Personally, what I’d like to see is some kind of real-time fatigue monitoring system in trucks. Monitoring driver performance in areas such as steering corrections, lane tracking, or other items could possibly warn of driver fatigue in real time.

Comments and questions welcome.