The study in the Journal of Occupational and Environmental Medicine (March 2009, Volume 51, Issue 3) found that the link between obesity and sleep apnea so strong that the federal government should mandate testing for sleep apnea for commercial motor vehicle drivers. Sleep apnea was found to increase the risks of a wreck 2 to 7 times over a fit driver. The study went on to confirm that 3.9 Million of the nations 14 million CMV drivers were possibly effected by sleep apnea. This is consistent with the industry estimate that 25% of the nations CDL drivers has obstructive sleep apnea, typically found in drivers whose body mass index was greater than 29.
I have posted previously on this topic, please see my earlier posts.