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NEW YORK (Reuters Health) - Long-distance truckers are almost three times more likely to get in an accident when they drive during midnight-to-dawn hours with few breaks, according to new research from Australia.
The findings run up against the realities of the global truck freight industry, where irregular schedules and incentive-based payment systems enticing drivers to the next load are still common, said Mark Stevenson. He led the study from the Monash University Accident Research Centre in Melbourne.
"If companies are setting schedules that require drivers to compete with their natural circadian rhythm, then that places them at a higher risk for a crash," Stevenson told Reuters Health.
He and his colleagues recruited a nearly all-male group of 530 truckers with a recent non-fatal road crash confirmed by a police report. They also tracked down 517 drivers with no crash reports to serve as a comparison group.
The truckers were recruited at rest stops along heavily traveled truck routes in New South Wales and Western Australia. Drivers in both groups answered questions related to sleep, driving and lifestyle habits during a 40-minute interview. They also wore a sleep monitor for one night. Participants were in their mid-40s, on average.
Drivers with less experience were three times more likely to be involved in a non-fatal accident and those traveling with an empty load were more than twice as likely to crash. Truckers who had been driving for less than eight hours had about half the odds of crashing as those further into their trip.
The new study confirms a link between late-night driving and crash risk, but also adds plenty of detail on other risk factors, said Dr. Barbara Phillips, from the University of Kentucky College of Medicine in Lexington.
For instance, the researchers found not having anti-lock braking systems on a truck was tied to a 50 percent higher risk of crashing. Lack of cruise control was tied to a 61 percent higher risk.
"That is news," said Phillips, who has studied long-haul drivers but was not involved in the current study.
"Some drivers prefer not to use cruise control because they think they have limited control of the vehicle," said Stevenson.
"But once cruise control is activated, it does assist the driver in maintaining a constant, safe speed," he said.
Truckers who drank caffeinated beverages had one third the odds of crashing as those who didn't, the researchers report in the American Journal of Epidemiology.
Contrary to previous research, Stevenson and his team found that sleep apnea, a sleep disorder, was not tied to crash risk. About 19 percent of drivers who had been in a crash and 16 percent of comparison drivers were determined to have "likely severe" apnea.
"With sleep apnea, you are getting very poor quality sleep. So some of the drivers are already starting work with a sleep deficit," Stevenson said.
But Phillips said the apnea monitors given to truckers in the study did not measure certain parameters which have been linked to an increased risk of accidents.
"Based on the methods used here, and the exclusion of crashes with deaths or injuries, I do not think it's a safe conclusion to draw," Phillips said of the sleep apnea finding.
The type of study design used by the researchers, called a "case-control," can be useful for studying small groups of people. But, as they point out, the comparison group may not have the exact same characteristics as drivers who had crashed.
Both Stevenson and Phillips agreed that truck drivers and car drivers will inevitably drive while sleep-deprived.
The current research offers some advice, Phillips said.
"One, drivers should drink caffeine. Two, they can use cruise control if they have it. And, three, they need to take frequent breaks," she said.
SOURCE: bit.ly/1kD0pp0 American Journal of Epidemiology, online December 18, 2013.