Transport Safety Public Symposium in Tokyo
Sleep-Disordered Breathing and Transport Safety

Preventing Accidents inNorth American Commercial Drivers
with Obstructive Sleep Apnea-Summary of Remarks-

Dr. Stefanos N. Kales
Associate Professor of Medicine, Harvard Medical School

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Introduction
There are many risks faced by drivers on the road today. Factors that heighten
the risk of a driver becoming involved in an accident include: the number ofhours a driver has slept or rested, the time of day, whether they have taken drugs
or medication, whether they have been drinking alcohol, and adverse conditions
on the road. Before any discussion of obstructive sleep apnea (OSA) and roadaccidents, it is important to note that there are many inter-related issues toconsider, and that a single line of defense for just one of these factors will not beenough to prevent a tragedy. We must have a strategy that employs a wide rangeof preventative measures.

is not surprising then, that the automobile industry, including companies like
Audi, Lamborghini, Volkswagen, and SEAT, is working to create technologies
that can detect when a driver is drowsy and take automated measures to avoid
an accident, even if the driver is incapacitated. This is especially important fordrivers with OSA.
Figure 2

Figure 1

Figure 3

The Reason Model, or “Swiss Cheese model,” developed by James T. Reason
is one such strategy.1 This model proposes the establishment of many diﬀerent
measures—deployed simultaneously or in series—in order to prevent accidents.
In 2003, this model was put to the test in Japan when a shinkansen train (bullet
train) driver fell asleep at the controls.2 Thanks to this strategic model, no one
was injured. Even though the driver fell asleep, there were other measures inplace to prevent a serious accident. Control systems installed in the train and therailway system worked together to stop the train automatically before it crashed.
This is just one case that supports the effectiveness of the Reason model. It

4

OSA is the clinically significant form of sleep-disordered breathing. It is themost common sleep disorder in the adult population worldwide and the leading
medical cause of excessive daytime sleepiness. It is also the most important sleep
disorder within the transportation industry.3 It is caused by the periodic closureof the upper airway, leading to a decrease or cessation of respiration periodically5

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Introduction
There are many risks faced by drivers on the road today. Factors that heighten
the risk of a driver becoming involved in an accident include: the number ofhours a driver has slept or rested, the time of day, whether they have taken drugs
or medication, whether they have been drinking alcohol, and adverse conditions
on the road. Before any discussion of obstructive sleep apnea (OSA) and roadaccidents, it is important to note that there are many inter-related issues toconsider, and that a single line of defense for just one of these factors will not beenough to prevent a tragedy. We must have a strategy that employs a wide rangeof preventative measures.

is not surprising then, that the automobile industry, including companies like
Audi, Lamborghini, Volkswagen, and SEAT, is working to create technologies
that can detect when a driver is drowsy and take automated measures to avoid
an accident, even if the driver is incapacitated. This is especially important fordrivers with OSA.
Figure 2

Figure 1

Figure 3

The Reason Model, or “Swiss Cheese model,” developed by James T. Reason
is one such strategy.1 This model proposes the establishment of many diﬀerent
measures—deployed simultaneously or in series—in order to prevent accidents.
In 2003, this model was put to the test in Japan when a shinkansen train (bullet
train) driver fell asleep at the controls.2 Thanks to this strategic model, no one
was injured. Even though the driver fell asleep, there were other measures inplace to prevent a serious accident. Control systems installed in the train and therailway system worked together to stop the train automatically before it crashed.
This is just one case that supports the effectiveness of the Reason model. It

4

OSA is the clinically significant form of sleep-disordered breathing. It is themost common sleep disorder in the adult population worldwide and the leading
medical cause of excessive daytime sleepiness. It is also the most important sleep
disorder within the transportation industry.3 It is caused by the periodic closureof the upper airway, leading to a decrease or cessation of respiration periodically5

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

throughout sleep. The consequences of this are several fold, including intermittent
disturbances in breathing because of upper airway obstruction, disrupted sleep,
poor sleep, excessive daytime sleepiness, a deterioration of the ability to think,deﬁcits in hand-eye coordination and reaction time, impaired vigilance, and on
occasion, sleep attacks that can cause a patient to fall asleep suddenly without
warning. These symptoms may or may not be recognized by the patient. Thosewith OSA often gradually become accustomed to their disorder over many years,
and may not realize how poorly or tired they feel. In fact, it is often only after
a month of treatment that a patient will tell their physician that they did not
realize just how much they suﬀered for so many years.

Background: OSA in US-North American Drivers

sleepiness, over 1,000 deaths and over 20,000 serious injuries are due to driver
fatigue every year. While there are many factors contributing to driver fatigue
that can only be controlled by the driver or their employer, such as: when adriver goes to bed, when they wake up, what they do during off hours, howmuch they drink, what they eat, their shift, the number of hours they work,and the route they drive; there are also many issues that can be mitigated byoccupational medicine physicians to alleviate the risk that drowsiness poses.
During a medical exam, occupational medicine physicians can screen for certain
conditions like the presence of drugs and alcohol, as well as the presence ofsleep disorders, in particular OSA.8
Figure 5

Diﬀerent estimates exist regarding the proportion of accidents that involve orare attributable to sleepy drivers, but most scientists agree that it is somewhere
between 10% and 30% of all accidents.4-6 This makes sleepy drivers a very
important group. There is the potential for a very large reduction in accidents if
we can reduce the risk this group of drivers poses.
Figure 4

There are over 5,000 fatalities and over 100,000 serious injuries every year due
to large bus and truck crashes in the United States.7 Assuming 20% are due to

6

The presence of obesity increases the risk for OSA. Right now, 40-50% of thecommercial drivers in the United States are obese based on their body massindex (BMI).3 The relationship between obesity and OSA in middle-aged men
is tightly correlated. If we take a man in the United States or Europe with a
BMI of 32 or higher, even without knowing any other statistic, we can say that
this person has approximately a 75% chance of having OSA. The vast majorityof these cases will not be recognized. They will not be diagnosed, and they will
not be receiving treatment. Thus, these drivers are operating vehicles at risk tothemselves, their companies, and the general public.

7

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

throughout sleep. The consequences of this are several fold, including intermittent
disturbances in breathing because of upper airway obstruction, disrupted sleep,
poor sleep, excessive daytime sleepiness, a deterioration of the ability to think,deﬁcits in hand-eye coordination and reaction time, impaired vigilance, and on
occasion, sleep attacks that can cause a patient to fall asleep suddenly without
warning. These symptoms may or may not be recognized by the patient. Thosewith OSA often gradually become accustomed to their disorder over many years,
and may not realize how poorly or tired they feel. In fact, it is often only after
a month of treatment that a patient will tell their physician that they did not
realize just how much they suﬀered for so many years.

Background: OSA in US-North American Drivers

sleepiness, over 1,000 deaths and over 20,000 serious injuries are due to driver
fatigue every year. While there are many factors contributing to driver fatigue
that can only be controlled by the driver or their employer, such as: when adriver goes to bed, when they wake up, what they do during off hours, howmuch they drink, what they eat, their shift, the number of hours they work,and the route they drive; there are also many issues that can be mitigated byoccupational medicine physicians to alleviate the risk that drowsiness poses.
During a medical exam, occupational medicine physicians can screen for certain
conditions like the presence of drugs and alcohol, as well as the presence ofsleep disorders, in particular OSA.8
Figure 5

Diﬀerent estimates exist regarding the proportion of accidents that involve orare attributable to sleepy drivers, but most scientists agree that it is somewhere
between 10% and 30% of all accidents.4-6 This makes sleepy drivers a very
important group. There is the potential for a very large reduction in accidents if
we can reduce the risk this group of drivers poses.
Figure 4

There are over 5,000 fatalities and over 100,000 serious injuries every year due
to large bus and truck crashes in the United States.7 Assuming 20% are due to

6

The presence of obesity increases the risk for OSA. Right now, 40-50% of thecommercial drivers in the United States are obese based on their body massindex (BMI).3 The relationship between obesity and OSA in middle-aged men
is tightly correlated. If we take a man in the United States or Europe with a
BMI of 32 or higher, even without knowing any other statistic, we can say that
this person has approximately a 75% chance of having OSA. The vast majorityof these cases will not be recognized. They will not be diagnosed, and they will
not be receiving treatment. Thus, these drivers are operating vehicles at risk tothemselves, their companies, and the general public.

7

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Figure 6

A Comparison and Contrast of the United States and Asia regarding
OSA and Drivers
Figure 7

Studies that compare patients with sleep apnea to normal drivers show thatthose with sleep apnea are basically two times to 11 times more likely to havean accident. Conservatively, this means that passenger car drivers who have been
diagnosed in a clinic with sleep apnea have a motor vehicle accident risk 3-4
times that of the average person in the general population.9
There is a solution to this problem. In clinical studies, drivers with OSA who
receive continuous positive airway pressure (CPAP) treatment see their rate ofaccidents reduced to a level in line with control subjects who do not have OSA.
In other words, this treatment can be eﬀective in almost completely removing
the driving risk of this disorder.

There are both differences and similarities with respect to OSA within the
United States compared to Japan and Asia.10 Among the similarities is that thisdisorder is under-recognized everywhere. Most people who have OSA do notrealize it. Even if people in their family know that they are snoring, they do notnecessarily know that this is a medical problem. Many people think that snoringis a benign habit and that those who snore are getting very restful and peacefulsleep. This is clearly a misconception.
In both Japan and the United States, obesity increases the risk of sufferingfrom sleep apnea. Even though the proportion and prevalence of obesity aredramatically different in the two areas, the prevalence of sleep disorderedbreathing, from mild up all the way to severe, is similar, at as much as 25%
among commercial drivers in both countries.11 Thus, OSA is a causal factor forserious accidents in both societies.
The main diﬀerence between the United States and Japan is that most of thedrivers with OSA in Japan are not obese.10-12 Some have suggested that this89

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Figure 6

A Comparison and Contrast of the United States and Asia regarding
OSA and Drivers
Figure 7

Studies that compare patients with sleep apnea to normal drivers show thatthose with sleep apnea are basically two times to 11 times more likely to havean accident. Conservatively, this means that passenger car drivers who have been
diagnosed in a clinic with sleep apnea have a motor vehicle accident risk 3-4
times that of the average person in the general population.9
There is a solution to this problem. In clinical studies, drivers with OSA who
receive continuous positive airway pressure (CPAP) treatment see their rate ofaccidents reduced to a level in line with control subjects who do not have OSA.
In other words, this treatment can be eﬀective in almost completely removing
the driving risk of this disorder.

There are both differences and similarities with respect to OSA within the
United States compared to Japan and Asia.10 Among the similarities is that thisdisorder is under-recognized everywhere. Most people who have OSA do notrealize it. Even if people in their family know that they are snoring, they do notnecessarily know that this is a medical problem. Many people think that snoringis a benign habit and that those who snore are getting very restful and peacefulsleep. This is clearly a misconception.
In both Japan and the United States, obesity increases the risk of sufferingfrom sleep apnea. Even though the proportion and prevalence of obesity aredramatically different in the two areas, the prevalence of sleep disorderedbreathing, from mild up all the way to severe, is similar, at as much as 25%
among commercial drivers in both countries.11 Thus, OSA is a causal factor forserious accidents in both societies.
The main diﬀerence between the United States and Japan is that most of thedrivers with OSA in Japan are not obese.10-12 Some have suggested that this89

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

may be due to diﬀerences in facial structure or diﬀerences in the distribution
and the amount of body fat per body weight; however, the exact reason why
the Japanese population experiences medical co-morbidities related to obesity
at a lower BMI is not yet known. Regardless of which factor is considered,be it hypertension, increased blood sugar, increases in blood cholesterol andtriglycerides, Type II diabetes mellitus, or OSA, the Japanese population on
average develops these problems at a lower BMI than western populations.13

Figure 8

For this reason, unlike in the United States, where BMI information orquestionnaires are used to identify patients with a high-risk of OSA for further
screening, in Japan, pulse oximetry or air ﬂow monitoring is usually necessary to
screen and identify OSA patients.2, 11

Overview of Strategies in North America
Strategies used in North America to identify drivers with sleep apnea include
the use of an official (federal) driver’s license medical examination form andvarious questionnaires in which drivers are asked to report their own symptoms.
Drivers do not always offer accurate answers on these questionnaires,3 but
physicians can often convince drivers to divulge information that they would notnormally report on a form during interviews within the occupational medicine
examination. The way in which a question is posed is important. While a driveris less likely to admit to snoring if asked about it on a questionnaire, during a
medical examination, a physician might convince a driver to admit to snoring byjoking about whether or not their signiﬁcant other complains about the noise.
A skilled physician can often obtain information that a questionnaire cannot.

10

In the United States, commercial drivers of vehicles exceeding a certain weightor traveling on certain roads are required to have a medical examination at least
every two years. The only mandated screening for sleep disorders in the UnitedStates is a single question on the form used for this examination. It asks the yesor no question, “Do you have sleep disorders, pauses in breathing while asleep,
daytime sleepiness, loud snoring?” Among the drivers who are at high risk for
OSA, 85% answer this question “No.”14
However, on the positive side, there do exist more eﬀective questionnaires, suchas the Somni-Sage questionnaire. This questionnaire was developed by Dr. MarkBerger and pioneered in the population at Schneider National, a large trucking
company with over 10,000 drivers.15 It asks more than 20 questions about
sleep, collar size, height, and weight, as well as other matters which a driver
may not associate with sleep apnea, but which relate to it. For example, it asks,“How many times do you wake up at night to urinate?” Drivers tend to answer
a question like this one honestly. Likewise, they tend to answer more honestly
about their height and weight than about snoring or being tired during the day.
A statistical algorithm is employed based on the totality of all the answers togenerate a high-risk or a low-risk score. Drivers evaluated to be high risk aresent for sleep studies, and 70% of these higher risk drivers are found to have11Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

may be due to diﬀerences in facial structure or diﬀerences in the distribution
and the amount of body fat per body weight; however, the exact reason why
the Japanese population experiences medical co-morbidities related to obesity
at a lower BMI is not yet known. Regardless of which factor is considered,be it hypertension, increased blood sugar, increases in blood cholesterol andtriglycerides, Type II diabetes mellitus, or OSA, the Japanese population on
average develops these problems at a lower BMI than western populations.13

Figure 8

For this reason, unlike in the United States, where BMI information orquestionnaires are used to identify patients with a high-risk of OSA for further
screening, in Japan, pulse oximetry or air ﬂow monitoring is usually necessary to
screen and identify OSA patients.2, 11

Overview of Strategies in North America
Strategies used in North America to identify drivers with sleep apnea include
the use of an official (federal) driver’s license medical examination form andvarious questionnaires in which drivers are asked to report their own symptoms.
Drivers do not always offer accurate answers on these questionnaires,3 but
physicians can often convince drivers to divulge information that they would notnormally report on a form during interviews within the occupational medicine
examination. The way in which a question is posed is important. While a driveris less likely to admit to snoring if asked about it on a questionnaire, during a
medical examination, a physician might convince a driver to admit to snoring byjoking about whether or not their signiﬁcant other complains about the noise.
A skilled physician can often obtain information that a questionnaire cannot.

10

In the United States, commercial drivers of vehicles exceeding a certain weightor traveling on certain roads are required to have a medical examination at least
every two years. The only mandated screening for sleep disorders in the UnitedStates is a single question on the form used for this examination. It asks the yesor no question, “Do you have sleep disorders, pauses in breathing while asleep,
daytime sleepiness, loud snoring?” Among the drivers who are at high risk for
OSA, 85% answer this question “No.”14
However, on the positive side, there do exist more eﬀective questionnaires, suchas the Somni-Sage questionnaire. This questionnaire was developed by Dr. MarkBerger and pioneered in the population at Schneider National, a large trucking
company with over 10,000 drivers.15 It asks more than 20 questions about
sleep, collar size, height, and weight, as well as other matters which a driver
may not associate with sleep apnea, but which relate to it. For example, it asks,“How many times do you wake up at night to urinate?” Drivers tend to answer
a question like this one honestly. Likewise, they tend to answer more honestly
about their height and weight than about snoring or being tired during the day.
A statistical algorithm is employed based on the totality of all the answers togenerate a high-risk or a low-risk score. Drivers evaluated to be high risk aresent for sleep studies, and 70% of these higher risk drivers are found to have11Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

an apnea-hypopnea index of 10 or more, which is considered deﬁnitive sleep
apnea.15 The Somni-Sage questionnaire is considered generally effective, andcan be made even more eﬀective by combining it with objective tests to ensurethat even the high-risk drivers who provide inaccurate or deceptive answers
about their height and weight and symptoms are identiﬁed as well.

positive for OSA. Notably, in this case in Israel, the drivers denied symptoms
of sleep apnea and daytime sleepiness. Yet when asked to take a Multiple Sleep
Latency Test, which is a napping test administered during the day, 50% of
these drivers produced abnormal results consistent with objectively measured
excessive daytime sleepiness.
Figure 9

It is clear that drivers talk to each other about these tests and change their
behavior to avoid a sleep apnea diagnosis. They do this because they do notnecessarily want to accept treatment. Even though it may make them feelbetter, they do not want to have the restriction of extra medical testing andextra monitoring. In 2006, the very ﬁrst year that Schneider National started
using this questionnaire, 29% of drivers admitted that they had excessive
daytime sleepiness in some form or another. The proportion of drivers willingto admit this went down every year after that, finally reaching 6% in 2010.15
The population of drivers is basically the same, so it is thought that the actual
reason behind this drop was that drivers talked to each other, learned that thecompany was trying to identify sleepy drivers, and changed their answers to
avoid being diagnosed with a sleep disorder. Nevertheless, the Somni-Sagequestionnaire and program maintained a predictive value of roughly 70% every
single year, meaning that the prevalence of sleep apnea remained at 20%. Thus,
the questionnaire was still eﬀective even after drivers changed their behavior.
According to data collected by the University of Pennsylvania, 50% ofcommercial drivers in North America have a BMI of 30 or greater.16 The point
where there is the strongest correlation between BMI and OSA is at a BMI
greater than or equal to 33 among North American drivers. In particular, usinga screening cutoﬀ of a BMI of 33, OSA can be predicted with 77% sensitivity
and 71% speciﬁcity in the North American driver population.16
A similar correlation can be found in certain places elsewhere throughout
the world, such as in Israel, which has a largely European population. It was
decided there that all drivers with a BMI of 32 or greater would be tested forsleep apnea. The predictive value of that test was very similar. It was found that
there is a roughly 75% chance that a male with a BMI of 32 or greater will
have OSA.17 This was conﬁrmed in a sleep laboratory, where 78% in fact tested

12

Returning to North America, another strategy being employed to detect OSA
is the development of guidelines that can help occupational medicine physicians
screen whether or not a driver has this disorder. The most commonly used
guidelines for detecting sleep apnea right now in the United States are the Joint
Task Force Guidelines or Joint Task Force Consensus Criteria. These guidelines
were published in two medical journals in 2006, the Journal of Occupational andEnvironmental Medicine and Chest.18, 19 They were developed by three medical
societies, the American College of Occupational and Environmental Medicine,
the American College of Chest Physicians, and the National Sleep Foundation.
The guidelines set the criteria for determining sleep apnea based on objective
factors, such as a BMI of 35 or greater and neck circumference. In the UnitedStates, a neck circumference greater than 17 inches for men is considered to
be a risk factor for sleep apnea. Because body sizes tend to increase somewhat
symmetrically, most drivers with a BMI of 35 or greater will have a neck13

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

an apnea-hypopnea index of 10 or more, which is considered deﬁnitive sleep
apnea.15 The Somni-Sage questionnaire is considered generally effective, andcan be made even more eﬀective by combining it with objective tests to ensurethat even the high-risk drivers who provide inaccurate or deceptive answers
about their height and weight and symptoms are identiﬁed as well.

positive for OSA. Notably, in this case in Israel, the drivers denied symptoms
of sleep apnea and daytime sleepiness. Yet when asked to take a Multiple Sleep
Latency Test, which is a napping test administered during the day, 50% of
these drivers produced abnormal results consistent with objectively measured
excessive daytime sleepiness.
Figure 9

It is clear that drivers talk to each other about these tests and change their
behavior to avoid a sleep apnea diagnosis. They do this because they do notnecessarily want to accept treatment. Even though it may make them feelbetter, they do not want to have the restriction of extra medical testing andextra monitoring. In 2006, the very ﬁrst year that Schneider National started
using this questionnaire, 29% of drivers admitted that they had excessive
daytime sleepiness in some form or another. The proportion of drivers willingto admit this went down every year after that, finally reaching 6% in 2010.15
The population of drivers is basically the same, so it is thought that the actual
reason behind this drop was that drivers talked to each other, learned that thecompany was trying to identify sleepy drivers, and changed their answers to
avoid being diagnosed with a sleep disorder. Nevertheless, the Somni-Sagequestionnaire and program maintained a predictive value of roughly 70% every
single year, meaning that the prevalence of sleep apnea remained at 20%. Thus,
the questionnaire was still eﬀective even after drivers changed their behavior.
According to data collected by the University of Pennsylvania, 50% ofcommercial drivers in North America have a BMI of 30 or greater.16 The point
where there is the strongest correlation between BMI and OSA is at a BMI
greater than or equal to 33 among North American drivers. In particular, usinga screening cutoﬀ of a BMI of 33, OSA can be predicted with 77% sensitivity
and 71% speciﬁcity in the North American driver population.16
A similar correlation can be found in certain places elsewhere throughout
the world, such as in Israel, which has a largely European population. It was
decided there that all drivers with a BMI of 32 or greater would be tested forsleep apnea. The predictive value of that test was very similar. It was found that
there is a roughly 75% chance that a male with a BMI of 32 or greater will
have OSA.17 This was conﬁrmed in a sleep laboratory, where 78% in fact tested

12

Returning to North America, another strategy being employed to detect OSA
is the development of guidelines that can help occupational medicine physicians
screen whether or not a driver has this disorder. The most commonly used
guidelines for detecting sleep apnea right now in the United States are the Joint
Task Force Guidelines or Joint Task Force Consensus Criteria. These guidelines
were published in two medical journals in 2006, the Journal of Occupational andEnvironmental Medicine and Chest.18, 19 They were developed by three medical
societies, the American College of Occupational and Environmental Medicine,
the American College of Chest Physicians, and the National Sleep Foundation.
The guidelines set the criteria for determining sleep apnea based on objective
factors, such as a BMI of 35 or greater and neck circumference. In the UnitedStates, a neck circumference greater than 17 inches for men is considered to
be a risk factor for sleep apnea. Because body sizes tend to increase somewhat
symmetrically, most drivers with a BMI of 35 or greater will have a neck13

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

circumference greater than 17. Over 90% of those who are judged to be highrisk by the Joint Task Force Screening Criteria will be found to actually have
OSA during sleep laboratory testing. This poses a new problem, which is thatwhen tests are so highly predictive of a disorder, the sensitivity goes downbecause false positives are no longer being detected. In fact, these tests only
estimate the prevalence of sleep apnea to be 12-13%,14 when it is known thatthe actual prevalence is closer to 20-25% among driver populations.3,15 While
this suggests they are not the ideal screening criteria, they are generally accepted
because they have been published by medical societies and validated in several
American occupational medicine clinics.

It has been clearly shown through multiple studies using this test that lapses inattention increase dramatically along with sleep deprivation.
Figure 11

Figure 10

It is even possible to discriminate between diﬀerent individuals using this test.
A normal sleeper has a typical reaction time of less than one half of one second.
Those with micro sleeps will have reaction times of 500 milliseconds or greater.
For these people, most of their reaction times will be normal, but there may belapses during the ten-minute test. Conversely, “macro sleepers” who fall asleep
for the whole test will have almost no reaction time responses.20

Beyond the guidelines, another potential method being developed to detect
OSA is functional testing.20 One such test is the Psychomotor Vigilance Test,a handheld examination of reaction time. During this test, the subject is asked
to look at a screen. At random intervals over ten minutes, a light will appear. As
soon as the subject sees the light, they are asked to press a button. When they
do so, their reaction time is recorded and the light is brieﬂy stopped. This lightstimulus is repeated hundreds of times at random intervals over the ten minutetest, making it both a test of reaction time as well as sustained alertness andvigilance.

14

15

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

circumference greater than 17. Over 90% of those who are judged to be highrisk by the Joint Task Force Screening Criteria will be found to actually have
OSA during sleep laboratory testing. This poses a new problem, which is thatwhen tests are so highly predictive of a disorder, the sensitivity goes downbecause false positives are no longer being detected. In fact, these tests only
estimate the prevalence of sleep apnea to be 12-13%,14 when it is known thatthe actual prevalence is closer to 20-25% among driver populations.3,15 While
this suggests they are not the ideal screening criteria, they are generally accepted
because they have been published by medical societies and validated in several
American occupational medicine clinics.

It has been clearly shown through multiple studies using this test that lapses inattention increase dramatically along with sleep deprivation.
Figure 11

Figure 10

It is even possible to discriminate between diﬀerent individuals using this test.
A normal sleeper has a typical reaction time of less than one half of one second.
Those with micro sleeps will have reaction times of 500 milliseconds or greater.
For these people, most of their reaction times will be normal, but there may belapses during the ten-minute test. Conversely, “macro sleepers” who fall asleep
for the whole test will have almost no reaction time responses.20

Beyond the guidelines, another potential method being developed to detect
OSA is functional testing.20 One such test is the Psychomotor Vigilance Test,a handheld examination of reaction time. During this test, the subject is asked
to look at a screen. At random intervals over ten minutes, a light will appear. As
soon as the subject sees the light, they are asked to press a button. When they
do so, their reaction time is recorded and the light is brieﬂy stopped. This lightstimulus is repeated hundreds of times at random intervals over the ten minutetest, making it both a test of reaction time as well as sustained alertness andvigilance.

14

15

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Figure 12

could be expected, when OSA patients were given alcohol, their performance
deteriorated dramatically.22
What all of these tests clearly show is that sleep apnea is a serious safety risk.
Allowing drivers with sleep apnea to drive without treatment is equivalent toallowing drunk driving to occur without any intervention. The performance ofa driver with untreated sleep apnea can be compared to a driver with a blood
alcohol concentration of 0.06 to 0.08.
It should be noted that the time of day is an important risk factor. The relativerisk of a crash is lowest at 9 or 10 AM in the morning and 7 to 8 PM at night.
The highest risk times are midnight, up to 5 o’clock in the morning, and thenagain in the afternoon at 1 to 2 o’clock. Drivers with OSA can be expected toperform especially poorly at these times.23

The Psychomotor Vigilance Test is not the only functional test that canpotentially detect OSA. Driving simulators are another type of test that is underinvestigation. The Aus-Ed Driving Simulator is well known among these.21, 22
It was created by teams from Australia and Edinburgh, Scotland, hence thename. It can be programmed for right lane or left lane driving, depending on
the driver’s home country. It simulates night driving on a rural road. In thesimulator, trucks periodically appear in front of the driver, and the subjects are
asked to break all the way to a complete stop whenever they see one. They alsoneed to maintain their lane as well as they can. The key measure on this test is
steering deviation – how closely a driver follows their designated lane of travel
as opposed to deviating right and left in the lane. It is possible to crash this test,
but that is relatively rare. Crashes tend to indicate even more serious sleepiness.
A study was run using this driving simulator on a group of drivers with OSA
and a control group that did not have OSA. The OSA patients had more
steering deviation than the control subjects even when the control subjects had
a restricted time in bed and the OSA patients were allowed to sleep as normal.
Adding sleep restriction to the sleep apnea patients created a remarkableelevation in steering deviation. Even in the presence of alcohol, control subjects
drove better than the OSA patients who had not consumed alcohol. As

16

OSA & Accident Risk Commercial Drivers
Data shows a correlation between accident risk and OSA.24 Most studies done
to date have examined patients from sleep clinics, and these patients may besomewhat different from commercial drivers, who typically do not complain
about sleep disorders. However, looking at self-reported body mass indices,
new recruit drivers with a BMI of greater than 35 had a 40-50% increased
risk of truck accidents compared to non-obese colleagues.25 In another study
taking a random sample of United States transportation operators and asking
about accident risk and its connection to sleep complaints in terms of exposure
to accidents and near-misses, it was found that there were increased odds for
accidents connected to any type of sleep complaint at all.26 In particular, thestudy found that excessive daytime sleepiness, excessive use of stimulants,
and whether the subject had a history of having been in an accident while
commuting to and f rom work was correlated to an increased risk of aprofessional crash or near-miss that is 4 to 5 times greater than the baseline risk.
Sleep complaints elevated accident risk 2 to 4 fold. Basically, any type of sleep
complaint increased the risk of reporting an accident or near-miss.26

17

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Figure 12

could be expected, when OSA patients were given alcohol, their performance
deteriorated dramatically.22
What all of these tests clearly show is that sleep apnea is a serious safety risk.
Allowing drivers with sleep apnea to drive without treatment is equivalent toallowing drunk driving to occur without any intervention. The performance ofa driver with untreated sleep apnea can be compared to a driver with a blood
alcohol concentration of 0.06 to 0.08.
It should be noted that the time of day is an important risk factor. The relativerisk of a crash is lowest at 9 or 10 AM in the morning and 7 to 8 PM at night.
The highest risk times are midnight, up to 5 o’clock in the morning, and thenagain in the afternoon at 1 to 2 o’clock. Drivers with OSA can be expected toperform especially poorly at these times.23

The Psychomotor Vigilance Test is not the only functional test that canpotentially detect OSA. Driving simulators are another type of test that is underinvestigation. The Aus-Ed Driving Simulator is well known among these.21, 22
It was created by teams from Australia and Edinburgh, Scotland, hence thename. It can be programmed for right lane or left lane driving, depending on
the driver’s home country. It simulates night driving on a rural road. In thesimulator, trucks periodically appear in front of the driver, and the subjects are
asked to break all the way to a complete stop whenever they see one. They alsoneed to maintain their lane as well as they can. The key measure on this test is
steering deviation – how closely a driver follows their designated lane of travel
as opposed to deviating right and left in the lane. It is possible to crash this test,
but that is relatively rare. Crashes tend to indicate even more serious sleepiness.
A study was run using this driving simulator on a group of drivers with OSA
and a control group that did not have OSA. The OSA patients had more
steering deviation than the control subjects even when the control subjects had
a restricted time in bed and the OSA patients were allowed to sleep as normal.
Adding sleep restriction to the sleep apnea patients created a remarkableelevation in steering deviation. Even in the presence of alcohol, control subjects
drove better than the OSA patients who had not consumed alcohol. As

16

OSA & Accident Risk Commercial Drivers
Data shows a correlation between accident risk and OSA.24 Most studies done
to date have examined patients from sleep clinics, and these patients may besomewhat different from commercial drivers, who typically do not complain
about sleep disorders. However, looking at self-reported body mass indices,
new recruit drivers with a BMI of greater than 35 had a 40-50% increased
risk of truck accidents compared to non-obese colleagues.25 In another study
taking a random sample of United States transportation operators and asking
about accident risk and its connection to sleep complaints in terms of exposure
to accidents and near-misses, it was found that there were increased odds for
accidents connected to any type of sleep complaint at all.26 In particular, thestudy found that excessive daytime sleepiness, excessive use of stimulants,
and whether the subject had a history of having been in an accident while
commuting to and f rom work was correlated to an increased risk of aprofessional crash or near-miss that is 4 to 5 times greater than the baseline risk.
Sleep complaints elevated accident risk 2 to 4 fold. Basically, any type of sleep
complaint increased the risk of reporting an accident or near-miss.26

17

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

In the United States, the Federal Motor Carrier Safety Administration, thegovernment agency which is responsible for large trucks and buses, does not
require screening for sleep apnea other than the single question on medical
examination forms which was mentioned earlier. This is not eﬀective. Some in
the transportation industry realize that, and they are working to enhance thedetection of OSA among drivers. Because there are so many lawsuits ﬁled after
commercial drivers crash, and because many companies want to do the rightthing, companies like Schneider National have decided that it is better for theirdrivers, customers, and the company’s bottom line to implement unique sleep
apnea screening programs.
Figure 13

the company’s health insurance. Studies of the program’s eﬀect on accident risk
are ongoing.

OSA Treatment and Accident/Medical Costs
Data continues to be analyzed on the effect of OSA in terms of treatment,
accidents, and medical costs. Accident risks are not eliminated for people
treated with CPAP, but they are reduced signiﬁcantly,27 and thus, we expect that
accident costs would fall. OSA is associated with a higher risk of hypertension,
incident diabetes mellitus, incident stroke, heart attack, and sudden death;
therefore, we also expect that CPAP treatment ultimately decreases medical
costs.28 CPAP treatment for drivers with OSA is essentially a forward-looking
investment, because it is rare that a person can lose enough weight to eliminate
their sleep apnea. Furthermore, patients actually lose weight more efficiently
when they are treated with CPAP, as poor sleep tends to cause people to gain
weight due to important hormonal changes that occur during sleep.

Conclusions

Schneider National started its program in 2006.15 The OSA Program primarily
uses the Somni-Sage Questionnaire. Any drivers found to be high risk are sent
for a sleep study, and if they show an increased amount of sleep disorderedbreathing, with an apnea-hypopnea index of 5 or greater, they are required
to use a CPAP device at home and in their truck in order to maintain theiremployment with the company. For drivers who wish to take naps or sleep
overnight in a truck stop, the device can be plugged into their truck. The
company monitors treatment compliance via a wireless device. Monitoringis done every day for the first 30 days, and depending on compliance, it iscontinued over regular intervals after that. Treatment expenses are covered by

18

There are many different screening strategies for OSA. Some are somewhat
effective by themselves, others are not. It is important to combine strategies
together into a coherent overall method for screening and the prevention of
accidents. The combined strategies should be considered as a serial pathway. If adriver comes out as high risk at any point in the pathway, whether that is basedon their BMI, the results of a questionnaire, a reaction time test, or the outcomeof a driving simulation test, that driver should undergo a sleep test in order torule out the possibility that he or she might have a sleep disorder. Only drivers
that are consistently low risk throughout the entire process should be exempt
from this type of diagnostic procedure. In countries like Japan, where there is adiﬀerent distribution of BMI and diﬀerent relationship of BMI to sleep apnea,
it may be more diﬃcult to determine who is at high risk for having OSA, andit may be advisable to have the majority of drivers screened using portable orhome diagnostic medical devices.

19

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

In the United States, the Federal Motor Carrier Safety Administration, thegovernment agency which is responsible for large trucks and buses, does not
require screening for sleep apnea other than the single question on medical
examination forms which was mentioned earlier. This is not eﬀective. Some in
the transportation industry realize that, and they are working to enhance thedetection of OSA among drivers. Because there are so many lawsuits ﬁled after
commercial drivers crash, and because many companies want to do the rightthing, companies like Schneider National have decided that it is better for theirdrivers, customers, and the company’s bottom line to implement unique sleep
apnea screening programs.
Figure 13

the company’s health insurance. Studies of the program’s eﬀect on accident risk
are ongoing.

OSA Treatment and Accident/Medical Costs
Data continues to be analyzed on the effect of OSA in terms of treatment,
accidents, and medical costs. Accident risks are not eliminated for people
treated with CPAP, but they are reduced signiﬁcantly,27 and thus, we expect that
accident costs would fall. OSA is associated with a higher risk of hypertension,
incident diabetes mellitus, incident stroke, heart attack, and sudden death;
therefore, we also expect that CPAP treatment ultimately decreases medical
costs.28 CPAP treatment for drivers with OSA is essentially a forward-looking
investment, because it is rare that a person can lose enough weight to eliminate
their sleep apnea. Furthermore, patients actually lose weight more efficiently
when they are treated with CPAP, as poor sleep tends to cause people to gain
weight due to important hormonal changes that occur during sleep.

Conclusions

Schneider National started its program in 2006.15 The OSA Program primarily
uses the Somni-Sage Questionnaire. Any drivers found to be high risk are sent
for a sleep study, and if they show an increased amount of sleep disorderedbreathing, with an apnea-hypopnea index of 5 or greater, they are required
to use a CPAP device at home and in their truck in order to maintain theiremployment with the company. For drivers who wish to take naps or sleep
overnight in a truck stop, the device can be plugged into their truck. The
company monitors treatment compliance via a wireless device. Monitoringis done every day for the first 30 days, and depending on compliance, it iscontinued over regular intervals after that. Treatment expenses are covered by

18

There are many different screening strategies for OSA. Some are somewhat
effective by themselves, others are not. It is important to combine strategies
together into a coherent overall method for screening and the prevention of
accidents. The combined strategies should be considered as a serial pathway. If adriver comes out as high risk at any point in the pathway, whether that is basedon their BMI, the results of a questionnaire, a reaction time test, or the outcomeof a driving simulation test, that driver should undergo a sleep test in order torule out the possibility that he or she might have a sleep disorder. Only drivers
that are consistently low risk throughout the entire process should be exempt
from this type of diagnostic procedure. In countries like Japan, where there is adiﬀerent distribution of BMI and diﬀerent relationship of BMI to sleep apnea,
it may be more diﬃcult to determine who is at high risk for having OSA, andit may be advisable to have the majority of drivers screened using portable orhome diagnostic medical devices.

19

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Screening for OSA can produce a high yield. If the entire population ofcommercial drivers were screened worldwide, it would likely be found that atleast 10% and as many as 25% have OSA. It is rare for any form of occupational
medicine screening to produce such a high proportion of subjects diagnosed
with the condition being examined. Usually, positive results are uncommon. But
OSA is diﬀerent. It is very common, and it is an overlooked issue. The medical
community should be more aggressive about screening and diagnosing thisproblem.
When conducting screening, the best practice is to combine various typesof subjective and objective measures. The treatment of OSA does decrease
accidents. Accidents are multi-factorial, and so like with screening, multiple
layers of controls are required to ensure safety.
In addition to OSA screening, companies should intervene to make sure drivers
do not work an excessive numbers of hours and that they have appropriate rest
periods. Drivers that have medical or sleep disorders should be investigated byoccupational health departments and if found to have OSA only be allowed
to drive during the day time provided that they are compliant with CPAP
treatment.

point, the vehicle itself would sense that the driver is repeatedly on a rumble
strip and forcibly slow down, stop, or shut oﬀ the vehicle. Likewise, automobile
manufacturers are working on mechanisms that can detect how much a vehicle
is swaying in its lane or whether there are excessive deviations in the speed or
braking. These behaviors may also act as a warning, and through these systems
may set oﬀ an alarm, and if the driver continues to drive erratically, may cause
the vehicle to shut down.
While technology is the future of automotive safety, it is currently limited.
Drivers with OSA have a high risk of causing accidents, and for the time being,
it is important to continue careful medical monitoring of driver populations
in order to detect these drivers and prevent accidents before they happen.
Even when better technologies do become available, OSA screening, othermedical tests and administrative controls to minimize driver fatigue will remain
important as part of a multi-pronged Reason strategy.

There are many potential technological advances that can be used to enhancesafety. For example, a camera may be placed inside the cab of a truck or a busthat can monitor the driver’s pupil size or the rate at which the driver is closing
their eye or blinking, as well as the diﬀerent types of eye movements that thedriver is making. These factors are correlated with sleepiness. Such a camera
could be hooked up so that there is a threshold at which the technology gives
the driver an alarm, a signal, or even a vibration in their seat to wake them up.
Similarly, there are controls intrinsic to the vehicle or the road itself that may
be used to reduce the risk of accident. Rumble strips are used in the roadsof both the United States and Japan. These are not always effective. Whilethey may initially wake up the driver, often they give the driver the false
sense of security that they will be woken up if they fall asleep. There may be acomplementary design change to a vehicle that could be used, by which at some20

21

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

Screening for OSA can produce a high yield. If the entire population ofcommercial drivers were screened worldwide, it would likely be found that atleast 10% and as many as 25% have OSA. It is rare for any form of occupational
medicine screening to produce such a high proportion of subjects diagnosed
with the condition being examined. Usually, positive results are uncommon. But
OSA is diﬀerent. It is very common, and it is an overlooked issue. The medical
community should be more aggressive about screening and diagnosing thisproblem.
When conducting screening, the best practice is to combine various typesof subjective and objective measures. The treatment of OSA does decrease
accidents. Accidents are multi-factorial, and so like with screening, multiple
layers of controls are required to ensure safety.
In addition to OSA screening, companies should intervene to make sure drivers
do not work an excessive numbers of hours and that they have appropriate rest
periods. Drivers that have medical or sleep disorders should be investigated byoccupational health departments and if found to have OSA only be allowed
to drive during the day time provided that they are compliant with CPAP
treatment.

point, the vehicle itself would sense that the driver is repeatedly on a rumble
strip and forcibly slow down, stop, or shut oﬀ the vehicle. Likewise, automobile
manufacturers are working on mechanisms that can detect how much a vehicle
is swaying in its lane or whether there are excessive deviations in the speed or
braking. These behaviors may also act as a warning, and through these systems
may set oﬀ an alarm, and if the driver continues to drive erratically, may cause
the vehicle to shut down.
While technology is the future of automotive safety, it is currently limited.
Drivers with OSA have a high risk of causing accidents, and for the time being,
it is important to continue careful medical monitoring of driver populations
in order to detect these drivers and prevent accidents before they happen.
Even when better technologies do become available, OSA screening, othermedical tests and administrative controls to minimize driver fatigue will remain
important as part of a multi-pronged Reason strategy.

There are many potential technological advances that can be used to enhancesafety. For example, a camera may be placed inside the cab of a truck or a busthat can monitor the driver’s pupil size or the rate at which the driver is closing
their eye or blinking, as well as the diﬀerent types of eye movements that thedriver is making. These factors are correlated with sleepiness. Such a camera
could be hooked up so that there is a threshold at which the technology gives
the driver an alarm, a signal, or even a vibration in their seat to wake them up.
Similarly, there are controls intrinsic to the vehicle or the road itself that may
be used to reduce the risk of accident. Rumble strips are used in the roadsof both the United States and Japan. These are not always effective. Whilethey may initially wake up the driver, often they give the driver the false
sense of security that they will be woken up if they fall asleep. There may be acomplementary design change to a vehicle that could be used, by which at some20

21

Stefanos N. Kales

Preventing Accidents in North American Commercial Drivers with Obstructive Sleep Apnea-Summary of Remarks-

References
1. Reason, JT. Human error: models and management. BMJ. 2000 March 18; 320(7237): 768–770.
2. Tanigawa T, Horie S, Sakurai S, Iso H. Screening for sleep-disordered breathing at workplaces. Ind Health. 2005 Jan;43(1):53-7.
3. Zhang C, Berger M, Malhotra A, Kales SN. Portable diagnostic devices for identifying obstructive sleep apnea among commercial
motor vehicle drivers: considerations and unanswered questions. Sleep. 2012 Nov 1;35(11):1481-9.
4. Philip P. Sleepiness of occupational drivers. Ind Health. 2005 Jan;43(1):30-3.
5. Radun I, Summala H. Sleep-related fatal vehicle accidents: characteristics of decisions made by multidisciplinary investigation
teams. Sleep. 2004 Mar 15;27(2):224-7.
6. Akerstedt T. Consensus statement: fatigue and accidents in transport operations. J Sleep Res. 2000 Dec;9(4):395.
7. National Summary of Large Truck and Passenger Carriers Crashes: US Department of Transportation; 2010.
8. Certification Process for Drivers with Serious Medical Conditions: United States Government Accountability Oﬃce: 2008.
9. George CF. Sleep. 5: Driving and automobile crashes in patients with obstructive sleep apnoea/hypopnoea syndrome. Thorax. 2004
Sep;59(9):804-7.
10.Yamagishi K, Ohira T, Nakano H, Bielinski SJ, Sakurai S, Imano H, Kiyama M, Kitamura A, Sato S, Konishi M, Shahar E, Folsom
AR, Iso H, Tanigawa T. Cross-cultural comparison of the sleep-disordered breathing prevalence among Americans and Japanese.
Eur Respir J. 2010 Aug;36(2):379-84.
11.Sakurai S, Cui R, Tanigawa T, Yamagishi K, Iso H. Alcohol consumption before sleep is associated with severity of sleep-disorderedbreathing among professional Japanese truck drivers. Alcohol Clin Exp Res. 2007 Dec;31(12):2053-8.
12.Villaneuva AT, Buchanan PR, Yee BJ, Grunstein RR. Ethnicity and obstructive sleep apnoea. Sleep Med Rev. 2005 Dec;9(6):41936.
13.Pan WH, Yeh WT, Weng LC. Epidemiology of metabolic syndrome in Asia. Asia Pac J Clin Nutr. 2008;17 Suppl 1:37-42.
14.Parks P, Durand G, Tsismenakis AJ, Vela-Bueno A, Kales S. Screening for obstructive sleep apnea during commercial driver
medical examinations. J Occup Environ Med. 2009 Mar;51(3):275-82.
15.Berger M, Varvarigou V, Rielly A, Czeisler CA, Malhotra A, Kales SN. Employer-mandated sleep apnea screening and diagnosis
in commercial drivers. J Occup Environ Med. 2012 Aug;54(8):1017-25.
16.Gurubhagavatula I, Maislin G, Nkwuo JE, Pack AI. Occupational screening for obstructive sleep apnea in commercial drivers. Am
J Respir Crit Care Med. 2004 Aug 15;170(4):371-6.
17.Dagan Y, Doljansky JT, Green A, Weiner A. Body Mass Index (BMI) as a ﬁrst-line screening criterion for detection of excessive
daytime sleepiness among professional drivers. Traﬃc Inj Prev. 2006 Mar;7(1):44-8.
18.Hartenbaum N, Collop N, Rosen IM, Phillips B, George CF, Rowley JA, Freedman N, Weaver TE, Gurubhagavatula I, Strohl K,
Leaman HM, Moﬃtt GL, Rosekind MR. Sleep apnea and commercial motor vehicle operators: statement from the joint Task
Force of the American College of Chest Physicians, American College of Occupational and Environmental Medicine, and the
National Sleep Foundation. J Occup Environ Med. 2006 Sep;48(9 Suppl):S4-37.
19.Hartenbaum N, Collop N, Rosen IM, Phillips B, George CF, Rowley JA, Freedman N, Weaver TE, Gurubhagavatula I, Strohl K,
Leaman HM, Moﬃtt GL; American College of Chest Physicians; American College of Occupational and Environmental
Medicine; National Sleep Foundation. Sleep apnea and commercial motor vehicle operators: Statement from the joint task forceof the American College of Chest Physicians, the American College of Occupational and Environmental Medicine, and the
National Sleep Foundation. Chest. 2006 Sep;130(3):902-5.
20.Zhang C, Varvarigou V, Parks PD, Gautam S, Bueno AV, Malhotra A, Kales SN. Psychomotor vigilance testing of professional
drivers in the occupational health clinic: a potential objective screen for daytime sleepiness. J Occup Environ Med. 2012
Mar;54(3):296-302.
21.Vakulin A, Baulk SD, Catcheside PG, Antic NA, van den Heuvel CJ, Dorrian J, McEvoy RD. Driving simulator performanceremains impaired in patients with severe OSA after CPAP treatment. J Clin Sleep Med. 2011 Jun 15;7(3):246-53.
22.Vakulin A, Baulk SD, Catcheside PG, Antic NA, van den Heuvel CJ, Dorrian J, McEvoy RD. Eﬀects of alcohol and sleep
restriction on simulated driving performance in untreated patients with obstructive sleep apnea. Ann Intern Med. 2009 Oct
6;151(7):447-55.
23.Garbarino S, Nobili L, Beelke M, De Carli F, Ferrillo F. The contributing role of sleepiness in highway vehicle accidents. Sleep.
2001 Mar 15;24(2):203-6.
24.Tregear S, Reston J, Schoelles K, Phillips B. Obstructive Sleep Apnea and Risk of Motor Vehicle Crash: Systematic Review andMeta-Analysis. J Clin Sleep Med 2009;5(6):573-581.
25.Anderson JE, Govada M, Steﬀen TK, Thorne CP, Varvarigou V, Kales SN, Burks SV. Obesity is associated with the future risk ofheavy truck crashes among newly recruited commercial drivers. Accid Anal Prev. 2012 Nov;49:378-84.
26.Johnson K, Patel SR, Baur DM, Edens EN, Sherry P, Malhotra A, Kales SN. Association of Sleep Habits with Accidents and Near
Misses in United States Transportation Operators. [In Preparation].
27.George CF. Reduction in motor vehicle collisions following treatment of sleep apnoea with nasal CPAP. Thorax. 2001
Jul;56(7):508-12.
28.Hoﬀman B, Wingenbach DD, Kagey AN, Schaneman JL, Kasper D. The Long-Term Health Plan and Disability Cost Beneﬁt of
Obstructive Sleep Apnea Treatment in a Commercial MotorVehicle Driver Population. J Occup Environ Med. 2010;52(5):473-7.

22Transport Safety Public Symposium in Tokyo
Sleep-Disordered Breathing and Transport Safety

Preventing Accidents inNorth American Commercial Drivers
with Obstructive Sleep Apnea-Summary of RemarksSeptember 2013 1st Edition
Planning and publishing : International Association of Traffic and Safety Sciences
ADDRESS : 6-20,2-chome, Yaesu, Chuo-ku, Tokyo, 104-0028, Japa
TEL : +81-3-3273-7884 URL : http://www.iatss.or.jp/
Edit cooperation : Ako Umezawa©International Association of Traffic and Safety Sciences 2013
Printed in Japan