Welcome to the AmSleep Blog

a blog about sleep apnea and other sleep conditions

Michael Morgenstern, MD
Follow me:

Michael Morgenstern, MD

About the author: Dr. Michael Morgenstern is double board certified in Neurology and Sleep Medicine and the founder of the American Sleep Apnea Society. He is the Director of the Morgenstern Medical in Lake Success, NY, where he treats patients with sleep disorders and other neurological conditions.
Michael Morgenstern, MD
Follow me:

Railroad personel sleep apnea screening recommendations

All railway workers in safety sensitive positions should be routinely tested for sleep apnea and impaired function using objective measures. Sleep apnea in railway drivers represents a potentially reversible cause of a large number of railway incidents. Screening for sleep apnea needs to be comprehensive, focusing on identification of sleep apnea as well as an evaluation for signs of functional impairment. Education and other technological advances can also help support improving railway safety. Railway workers bear an awesome responsibility and many lives depend upon their ability to drive a train while fully functional, at any time, whether it be at 4 PM or at 4 AM. Research has demonstrated that self-reported symptoms of sleep apnea in transportation workers are often unreliable.

Those certified to drive a train should:

  • Have no sign of sleep apnea on Home Sleep Testing, Polysomnography (PSG) or provide evidence of successful sleep apnea treatment.
  • Pass a driving simulator test that mimics nighttime conditions and/or a maintenance of wakefulness test, demonstrating that they do not have a high likelihood of falling asleep when they need to be alert.

Those found to have sleep apnea need to be monitored to ensure compliance with treatment. Individuals without apnea should also be able to demonstrate that they are able to drive and maintain their level of alertness. Additionally, they should be tested at regular intervals to identify apnea that can develop at any time.

Implementation of these recommendations can be accomplished in a cost effective manner that will reduce fatigue related collisions, benefit the health and longevity of railway workers and reduce healthcare costs over time.

Costs and Benefits of Sleep Apnea Diagnosis & Treatment (part 6)

What are the potential costs of alternative the Federal Motor Carrier Safety Administration (FMCSA) and Federal Railway Administration (FRA) regulatory actions that would restrict the safety sensitive activities of transportation workers diagnosed with moderate-to-severe OSA?

Medical costs

The main costs relate to evaluation, diagnosis and treatment of sleep apnea. Costs may vary, depending upon providers, payors, regions and the types of tests being implemented. However, approximate costs can be estimated by looking at Medicare physician reimbursement fees.1 According to these figures, the cost of diagnosis would range from $170 for an HST to $796 for a negative HST followed by a confirmatory PSG. CPAP titration studies would cost about $658. A CPAP machine and supplies for 1 year costs about $1,000.An MWT, which is used to identify subsets of excessively sleepy individuals, costs about $424. However, there is great variation in the contracted rates of providers and insurance companies, providing an opportunity to reduce overall costs for high-volume screening programs.

Costs related to treatment

The average annual cost for treatment for an individual found to have sleep apnea, including physician follow up, additional supplies, and an additional CPAP titration study every 5 years is estimated to cost around $1,200/year 2 Alternative treatments for OSA, such as an oral appliance or surgery, would cost around $1,500 and $10,000, respectively. Furthermore, costs can be increased by failure rates of modalities of treatment then leading to another modality being tried.

The majority of costs are generally highest in the first year. Average costs can be lowered by starting treatment with CPAP in all patients, advancing to an oral appliance only after therapy failure with CPAP, and only utilizing surgery as a last resort for treatment.

Who would incur those costs? What are the benefits of such actions and who would realize them?

The costs related to evaluation, diagnosis, treatment and continued management of sleep apnea are usually paid for by an individual’s health insurance. It is less clear if insurance companies would cover the MWT testing. While this is the “gold standard” for evaluation of the ability to stay awake, it is not routinely implemented in the evaluation of patients with sleep apnea, as the majority of patients do not work in sensitive positions such as driving a train. In general, all reimbursement would be subject to variability in individual plans, deductibles, co-payments and related individual/family healthcare utilization. The benefits of treating sleep apnea are well described and elaborated upon below. While healthcare costs might increase in the short-term for patients diagnosed with the disease, long-term health care costs of individuals treated with sleep apnea are expected to decrease over time. In general, patients with untreated OSA incur additional costs of $1950 to $3899 per year in comparison to  those who do not have OSA Therefore, the health and financial benefits would accrue to the individual, employer and  to the public.

Health benefits of treatment

What are the potential improved health outcomes for individuals occupying safety sensitive transportation positions and would receive OSA treatment due to regulations?

There are well established relationships between untreated sleep apnea and the development or worsening of obesity, depression, hypertension, diabetes, stroke, coronary artery disease, and cardiac arrhythmia.  Individuals with untreated sleep apnea have a reduced quality of life and a shorter life span.Treating OSA successfully mitigates or reverses most of these risks.

What models or empirical evidence is available to use to estimate potential costs and benefits of alternative restrictions?

Several of the tests suggested in this paper might be considered “alternatives” to the traditional evaluation of sleep apnea, such as the MWT, for which we have provided cost data (see “Medical Cost” above) that is available from the Centers for Medicare and Medicaid Services.

Paying for apnea

What costs would be imposed on transportation workers with safety sensitive duties by requiring screening, evaluation, and treatment of OSA?

In general, screening, evaluation, and treatment of OSA is paid for by health insurance companies. However, transportation workers or their employers would be responsible for deductibles, co-payments and uncovered screening, evaluation and treatment of OSA. If patients do not report snoring or excessive sleepiness, coverage for a sleep test from an insurance company could be denied. In the general population, there is no specific incentive to under-report symptoms. However, as discussed above, under-reporting is common in transportation workers. This could contribute to cost of testing being shifted towards the workers and employers in many cases.

Are there any private or governmental sources of financial assistance? Would health insurance cover costs for screening and/or treatment of OSA?

As discussed, reimbursement varies based on the insurer. It is likely that all screening and treatment of OSA would be paid for in the cases of transportation workers. It may also be a shared cost or one that might need special negotiation if the decision is made to test all workers rather than only testing individuals who meet the sleep testing criteria determined for the general population.


  1. The American Academy of Sleep Medicine. Sleep Services Payment Comparison 2014 National Payment vs. 2015 National Payment. (Link)
  2. McKinsey& Company. The price of fatigue: The surprising economic costs of unmanaged sleep apnea. 2010. (Link).
  3. Knauert, Melissa, et al. “Clinical consequences and economic costs of untreated obstructive sleep apnea syndrome.” World Journal of Otorhinolaryngology-Head and Neck Surgery1 (2015): 17-27. (Link)

Testing Treating & Tracking Railway Drivers to Enhance Safety (part 4)

Making our railways safer

Given the high costs of railway disasters, applying a multimodal approach towards preventing accidents is prudent. A comprehensive approach should include testing for the presence of sleep apnea, evaluation for signs of functional impairment, and worker education to prevent and counteract sleepiness during work.

Railway workers provide an invaluable service, and their own lives as well as the lives of others are often dependent on their ability to drive a train while fully functional, at any time.Several technologies such as Positive Train Control (PTC) Systems have been developed and can provide one mechanism of improving safety. Still, a great deal of accidents are attributed to fatigue. Given the high prevalence of sleep apnea in railway drivers, the need for a comprehensive approach to screening is urgent.

With respect to rail, how would any OSA regulations and the current PTC requirements interrelate?

PTC systems can act as safety measures to improve overall railway safety. These devices can increase train safety through automation, such as technology that slow trains moving too fast around a curved section of rail. Despite this technology, it is of utmost importance to ensure the highest level of human performance because railway workers play an essential role in the safety of trains.

Objective sleep apnea testing for all workers

Which categories of transportation workers with safety sensitive duties should be required to undergo screening for OSA? On what basis did you identify those workers?

All transportation workers with safety sensitive duties should undergo sleep testing. The unique risks posed by railway workers in safety sensitive positions, especially drivers, as well as the great human and financial costs involved in each wreck justify screening every worker. However, unlike traditional assessments which rely strongly on patient self-report of symptoms, screening transportation workers should rely strongly on objective testing such as polysomnography, home sleep testing, maintenance of wakefulness testing and driving simulators.

Research has repeatedly demonstrated an inability for medical examiners to reliably elicit symptoms from transportation workers by traditional history (i.e. questions and answers). Establishing screening programs in these workers, therefore, needs to rely upon objective testing. This would provide for the safest and most prudent approach. It would also be the simplest to implement. Every worker with a need for sustained attention (i.e. drivers) should undergo diagnostic testing for sleep apnea such as home sleep testing or polysomnography. These tests will usually identify the presence of latent sleep apnea, which is undiagnosed in 40% to 80% of individuals who have the disease. In certain circumstances a polysomnogram, which is a more sensitive for the detection of sleep apnea, may be the preferred test.

The American Academy of Sleep Medicine (AASM) guidelines of 20091 are relied upon by the Federal Aviation Administration for their guide for medical examiners to screen for sleep apnea. While the AASM guidelines do consider “driving populations” as high-risk populations, the guidelines were geared towards an evaluation of the general population and therefore were not specifically devised for transportation workers.

Traditional sleep apnea evaluations that rely on subjective symptom reporting are unreliable in evaluating transportation workers. In clinical practice, the most commonly reported symptoms of sleep apnea include snoring and excessive sleepiness. Sleepiness is often self-reported or elicited and quantified through the use of surveys, such as the Epworth Sleepiness Scale (ESS). On average, individuals who are excessively sleepy have an ESS score of 10 or above and those with sleep apnea have an average ESS score of about 13. However, when transportation workers, such as commercial drivers, are surveyed at driver certification exams, they report very low ESS scores, that are, in fact, lower than the general community. Some drivers with OSA evidence “deception,” reporting even lower ESS scores than drivers without OSA .2 Similar observations about sleepiness were made in the cohort of Greek railway drivers (cited above) who had moderate to severe sleep apnea, but reported normal ESS scores. The drivers with the most severe cases of sleep apnea (mean AHI = 68) reported even lower ESS scores than the drivers with moderate apnea.3   Therefore, in lieu of using an ESS and other subjective measurements or self-reports to assess sleepiness due to the limitations mentioned above, the Maintenance of Wakefulness test (MWT) can be used for greater accuracy.

Maintenance of Wakefulness Testing

What alternative forms and degrees of restriction could the  the Federal Motor Carrier Safety Administration (FMCSA) and the Federal Railway Administration (FRA), place on the performance of safety-sensitive duties by transportation workers with moderate-to-severe OSA?

The MWT is the gold standard objective, a valid and reliable measure of excessive daytime sleepiness in clinical practice, which tests the ability of a subject to maintain wakefulness while engaging in a quiet and boring situation (i.e. sitting on a comfortable chair in a semi-dark room).The MWT can discriminate between sleepy and alert drivers with OSA. Research has found an association between drivers with OSA who are “sleepy” on MWT and those who perform poorly on driving simulators, suggesting that other factors play a role in poor real time driving performance. 6

The sleepier a driver is, the more likely their performance will suffer. In addition to sleep apnea, risk factors for fatigue among workers include uncertain shift times, long commutes, sub-optimal terminal sleeping conditions, and insufficient sleep before a night shift. Similar to reports from other shift workers, train drivers beginning their shift between 10 PM and 4 AM have reported sleeping insufficiently (fewer than 6 hours a day on average), which leaves them sleep deprived. 7 A relationship also exists between age and sleepiness; older patients with OSA are more likely to exhibit excessive sleepiness on an MWT. 8

While some individuals with OSA or who are sleep restricted are consistently impaired on driving simulators, others routinely function normally on a driving simulator. This suggests that genetic factors may play a role in determining a subset of individuals who are most likely to be impaired by OSA.Since the neurobehavioral response to sleep disruption cannot be solely accounted for by the presence of OSA or its severity, other objective testing is needed to establish that individuals are fit to drive trains.

Psychomotor vigilance testing

The Psychomotor Vigilance Test (PVT) is a sustained attention psychometric test that has not yet been established to predict poor driving performance. The PVT measures the reaction time of a subject’s response to visual stimuli. In sleep research it has been used to identify drowsiness secondary to disturbed or insufficient sleep.  The advantage of this test is that it can generally be performed in less than 10 minutes and provide immediate feedback regarding attention levels. However, we could not find any data during our review of related literature establishing that poor performance on the PVT can be used to predict impaired driving.  Further research is required to identify whether PVT or another short duration psychometric test might be utilized to identify drivers who are more likely to be impaired as a result of sleep deprivation or OSA.

Driving Simulators

Railway driving simulators or railway driving data analysis may offer the best possible tool to identify drivers who are impaired by OSA or other causes. While MWT indirectly gauges risk though identifying an individual’s ability to stay awake, driving simulation pinpoints performance that is impaired even when a driver is “awake.” Research looking at MWT to evaluate its ability to assess driver impairment has frequently compared MWT results to driving simulator performance.6, 9-13 Most of these studies have looked at the driving of an automobile, measuring steering deviation, lane deviation and crashes. In some studies, simulators have been set up to mimic nighttime driving.6 Simulators for railway driving track features such as speed approach of the crossing, head movements, and stopping compliance.14 Furthermore, some of the research that establishes that MWT could be used to assess driving ability in untreated patients with OSA analyzes actual driving session data.13 The best tool to identify drivers who are fit-for-duty or to flag drivers who have an underlying sleep disorder may be to utilize current railway simulators to mimic nighttime driving situations, which is when most railway accidents take place, or review driver data to track safety and performance metrics.

Fit for Duty

An important part of fatigue management is ensuring that all operators are ready to perform and fit for duty. Treating OSA may relieve the root cause of sleepiness in a driver. However, the only way to ensure that a driver is able to perform is to test their ability to stay awake and perform. Therefore, restrictions should focus on ensuring that those with OSA are treated and, perhaps equally important, that they are able to perform without the adverse effects of sleepiness.

All individuals who are diagnosed with mild, moderate or severe OSA and treated with Continuous Positive Airway Pressure (CPAP) should demonstrate that they are adherent to treatment. This is accomplished by CPAP devices that track compliance data as well as the efficacy of treatment. Individuals who undergo treatment with an oral appliance must undergo a sleep study to demonstrate that their device is effective to relieve the apnea. If effective, it is also important to ensure compliance. Recently developed technology allows compliance data to be tracked in oral appliances.

All individuals diagnosed with OSA, even those who deny any sleepiness and those who are treated successfully with CPAP or an oral appliance, should routinely demonstrate through an approved driving simulation or MWT that they are fit to drive in situations that require sustained attention.

How effective would these restrictions be in improving transportation safety?

Data from driving simulators and crash data have demonstrated that driving capabilities return in patients with OSA that are treated with CPAP. In motor vehicles, baseline performance has been shown to return within a matter of days. 15,16 It is advised that a screening program in railway drivers should also collect and continue to monitor safety data for continuous evaluation, quality control and program improvement.

The difference between mild, moderate and severe sleep apnea

Should any regulations differentiate requirements for patients with moderate, as opposed to severe, OSA?

Excessive sleepiness can be observed at any level of sleep apnea and is not limited to moderate-to-severe OSA. The most commonly utilized parameter to categorize the severity of sleep apnea is the apnea-hypopnea-index or the AHI. An AHI of < 5 is normal, 5-14 is considered to be mild sleep apnea, 15-29 is considered moderate, and 30 or more is considered to be severe OSA.  In fact, excessive sleepiness may even be present in patients with disordered breathing who might not be diagnosed with “mild” sleep apnea using the AHI, but would be diagnosed utilizing the respiratory disturbance index (RDI) that includes respiratory effort related arousals in the detection of abnormal events. While an AHI of 20 or greater has been shown as an independent risk factor for excessive sleepiness in some studies, 17 numerous studies have shown excessive sleepiness in patients with mild forms of OSA. For example, in the study of rail workers from Brazil mentioned above, 54.4% of those with OSA had a mild form that was associated with excessive sleepiness. Therefore, limiting regulations to those with moderate or severe OSA could leave a substantial portion of patients who have excessive sleepiness undetected even though their AHI might only qualify them as having “mild” sleep apnea (AHI <15). Furthermore, the use of HST, which is advocated for herein, reduces the accuracy of discriminating between mild and moderate sleep apnea or between moderate to severe apnea, as it tends to underestimate the total severity of sleep apnea.


  1. Epstein, Lawrence J., et al. “Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults.” J Clin Sleep Med3 (2009): 263-276. (Link)
  2. Kales, Stefanos N., and Madeleine G. Straubel. “Obstructive sleep apnea in North American commercial drivers.” Industrial health1 (2014): 13-24. (Link)
  3. Nena, Evangelia, et al. “Sleep-disordered breathing and quality of life of railway drivers in Greece.” CHEST Journal1 (2008): 79-86. (Link)
  4. Johns, Murray W. “Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: failure of the MSLT as a gold standard.” Journal of sleep research1 (2000): 5-11. (Link)
  5. Pizza, Fabio, et al. “Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task.” Sleep3 (2009): 382. (Link)
  6. Vakulin, Andrew, et al. “Individual variability and predictors of driving simulator impairment in patients with obstructive sleep apnea.” J Clin Sleep Med6 (2014): 647-55. (Link)
  7. Dorrian, Jillian, et al. “Simulated train driving: Fatigue, self-awareness and cognitive disengagement.” Applied ergonomics2 (2007): 155-166. (Link)
  8. Sagaspe, Patricia, et al. “Maintenance of wakefulness test as a predictor of driving performance in patients with untreated obstructive sleep apnea.”SLEEP 3 (2007): 327. (Link)
  9. George CF, Boudreau AC, Smiley A. Simulated driving performance in patients with obstructive sleep apnea. Am J Respir Crit Care Med 1996;154:175-81.
  10. Pizza F, Contardi S, Mondini S, Trentin L, Cirignotta F. Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task. Sleep 2009;32:382-91.
  11. Sagaspe P, Taillard J, Chaumet G, et al. Maintenance of wakefulness test as a predictor of driving performance in patients with untreated obstructive sleep apnea. Sleep 2007;30:327-30.
  12. Philip P, Chaufton C, Taillard J, et al. Maintenance of Wakefulness Test scores and driving performance in sleep disorder patients and controls. Int J Psychophysiol 2013;89:195-202.
  13. Philip P, Sagaspe P, Taillard J, et al. Maintenance of Wakefulness test, obstructive sleep apnea syndrome, and driving risk. Ann Neurol 2008;64:410-6.
  14. Larue, Grégoire S., et al. “Driver’s behavioural changes with new intelligent transport system interventions at railway level crossings—A driving simulator study.”Accident Analysis & Prevention 81 (2015): 74-85.  (Link)
  15. George CF. Reduction in motor vehicle collisions following treatment of sleep apnoea with nasal
    Thorax. 2001;56:508-512.
  16. Turkington PM, Sircar M, Saralaya D, Elliott MW. Time course of changes in driving simulator
    performance with and without treatment in patients with sleep apnoea hypopnoea syndrome. Thorax.
  17. Pack, Allan I., et al. “Risk factors for excessive sleepiness in older adults.”Annals of neurology6 (2006): 893-904.

The Risk of Untreated Sleep Apnea in Railroad Workers

Is there information (studies, data, etc.) available for estimating the future consequences resulting from individuals with OSA occupying safety sensitive transportation positions in the absence of new restrictions? 

According to the Federal Railway Administration (FRA) Office of Safety Analysis, there were 11,233 train incidents including 1,856 accidents and 1,314 derailments in 2015, resulting in 821 lives lost. Among commuter trains, 1453 passengers were injured and 17 were killed. The FRA has identified human factors to be the biggest problem, responsible as a primary cause 39% of the time. The majority of human factors are likely to be fatigue related, based on a five-year study of main-track train collisions by the FRA which found 30 percent of collisions to be related to fatigue. Of note, the term “fatigue” is routinely used by federal agencies such as the National Transportation Safety Board (NTSB) to describe what sleep specialists call excessive “sleepiness.” 3

Financial Impact

The greatest cost of railway accidents are the lives lost, but the direct and indirect financial costs of railway accidents are projected to be in the billions. The Department of Transportation’s Pipeline and Hazardous Materials Safety Administration, looking only at a subset of trains carrying ethanol or crude oil, project that these trains will derail 10 times per year on average over the next two decades, resulting in $4 billion in damages.4 These projections rely on data from prior catastrophes including the Lac-Mégantic accident in the Canadian province of Quebec, which killed 46 individuals and had costs estimated around $2.7 billion. Some make the case that these projections could be severely underestimated.5 For example, railroad companies have frequently cited a 2006 damage assessment report by the American Academy of Actuaries for the President’s Working Group on Financial Markets to estimate damages of an oil tanker explosion in a more densely populated area. Using the closest analogy, a truck bomb explosion would result in damages of $3 billion near Des Moines, $8.8 billion in San Francisco, and $11.8 billion near New York City. Despite debate over estimates, these cost projections only represents a fraction of the costs of the total number of railway accidents.

The Metro-North Passenger Train Derailment

On December 1st, 2013 shortly after 7:19 AM, a passenger train derailed in the Bronx, NY, killing 4, injuring 61 and causing $9 million in property damage.As of December 2015 an additional $38 million dollars in lawsuits had been settled.7   A single accident might also indirectly impact the contribution to GDP from workers traveling on a route that is temporarily disabled. An article in Fortune Magazine published after an Amtrak passenger derailment on May 13, 2015 cited company officials who estimated that a single day of lost service could cost $100 million to affected businesses and consumers. 8

Does any organization track the number of historical motor carrier or train accidents caused by OSA?

The NTSB issues accident reports following the investigation of train accidents in the United States. This data often explores prior medical records, often reporting on accidents that are caused by OSA. However, this data may underestimate OSA incidence due to cases of undiagnosed OSA.

  1. Fortune Magazine. What’s the economic impact of the Amtrak crash? May 2015.  (Link)
  2. Epstein, Lawrence J., et al. “Clinical guideline for the evaluation, management and long-term care of obstructive sleep apnea in adults.” J Clin Sleep Med3 (2009): 263-276. (Link)
  3. Kales, Stefanos N., and Madeleine G. Straubel. “Obstructive sleep apnea in North American commercial drivers.” Industrial health1 (2014): 13-24. (Link)
  4. Johns, Murray W. “Sensitivity and specificity of the multiple sleep latency test (MSLT), the maintenance of wakefulness test and the Epworth sleepiness scale: failure of the MSLT as a gold standard.” Journal of sleep research1 (2000): 5-11. (Link)
  5. Pizza, Fabio, et al. “Daytime sleepiness and driving performance in patients with obstructive sleep apnea: comparison of the MSLT, the MWT, and a simulated driving task.” Sleep3 (2009): 382. (Link)
  6. Vakulin, Andrew, et al. “Individual variability and predictors of driving simulator impairment in patients with obstructive sleep apnea.” J Clin Sleep Med6 (2014): 647-55. (Link)
  7. Dorrian, Jillian, et al. “Simulated train driving: Fatigue, self-awareness and cognitive disengagement.” Applied ergonomics2 (2007): 155-166. (Link)
  8. Sagaspe, Patricia, et al. “Maintenance of wakefulness test as a predictor of driving performance in patients with untreated obstructive sleep apnea.”SLEEP (2007): 327. (Link)

Prevalence of OSA in USA Railway Workers

Prevalence of OSA in the general population

What is the prevalence of moderate-to-severe obstructive sleep apnea (OSA) among the general adult U.S. population? 

The best available data suggests that sleep apnea is present in 9% of women and 24% of men ages 30 to 60 in the United States. This comes from the Wisconsin Cohort, a large epidemiological study, which found that self-reported sleepiness was also present in 2% of women and 4% of men leading to a diagnosis of sleep apnea syndrome.1 Wide ranges of OSA prevalence exists in population studies of sleep apnea and sleep apnea syndrome. Much of this variation can be attributed to the different ways sleep apnea and sleep can be measured.

How does this prevalence vary by age? 

sleep apnea prevalence adult males by BMI and ageIn the United States, a program for monitoring OSA over time isn’t available to provide us with a good estimate of prevalence by age. A model developed using data from the United Kingdom to estimate the prevalence of mild, moderate and severe OSA by age groups in the USshows that age and body mass index (BMI) influence the prevalence of all types of OSA. Evidence in railway workers suggests individuals who have a BMI ≥ 25 and are over 37 years old have a higher incidence of OSA.3

Prevalence of OSA in USA railway workers

What is prevalence of moderate-to-severe OSA among individuals occupying safety sensitive transportation positions? If it differs from that among the general population, why does it appear to do so?

The prevalence of sleep apnea in train operators has been shown to be higher than the general population. The reason is likely related to the number of train operators who are male, overweight, smoke, operate in shifts and have other risk factors for OSA.3

Prevalence and risk factors for obstructive sleep apnea syndrome in railway operators was examined in 2 studies3, 4 totaling 1,163 employees. The first study, which examined railway drivers* in Brazil who had an average age of 35.63 years and a mean BMI of 26.74, found that 35% of workers were diagnosed with Obstructive Sleep Apnea Syndrome. This included individuals who had mild apnea (Apnea Hypopnea Index, AHI of 5-14) and also had daytime sleepiness that could impair the operation of a train. The majority of workers of workers over 37 years old (51%) had sleep apnea. Since approximately 54.4% of the workers in the study were diagnosed with mild OSA, 25.3% with moderate OSA, and 20.3% with severe OSA, approximately 23% of those over 37 years of age had moderate to severe OSA (assuming an equal distribution across age and BMI in the study).

est prevgalence train drivers bmi age

The second study examined railway drivers in Greece and found OSA in 62% of workers whose average age and BMI was 47 years and 28.7, respectively. Similar to the Brazil railway drivers, where 23% were found to have moderate to severe apnea, 22% of the Greek railway drivers had moderate to severe apnea.4

Data on transportation workers in the US show similar descriptive statistics to the railway workers in Greece. For example, US transportation workers have an average BMI of 28.5 5 and an average age of 44.6,demographics that are strikingly similar to the cohort of Greek railway drivers (BMI of 28.7 and average age of 47). Generalization of these studies might be made to a US group of railroad workers, in lieu of actual OSA prevalence data from railway workers in the United States.

*The term train “conductors” utilized in the study “Prevalence of and risk factors for obstructive sleep apnea syndrome in Brazilian railroad workers” refers to “drivers.” This is implied in the article and was confirmed by email correspondence with the author, Renata Koyama, on 5/17/16.


  1. Lee W, Nagubadi S, Kryger MH, Mokhlesi B. Epidemiology of Obstructive Sleep Apnea: a Population-based Perspective. Expert review of respiratory medicine. 2008;2(3):349-364. doi:10.1586/17476348.2.3.349. (Link)
  2. Peppard, Paul E., et al. “Increased prevalence of sleep-disordered breathing in adults.” American journal of epidemiology(2013): kws342. (Link)
  3. Koyama, Renata G., et al. “Prevalence of and risk factors for obstructive sleep apnea syndrome in Brazilian railroad workers.” Sleep medicine8 (2012): 1028-1032. (Link)
  4. Nena, Evangelia, et al. “Sleep-disordered breathing and quality of life of railway drivers in Greece.” CHEST Journal1 (2008): 79-86. (Link)
  5. Luckhaupt, Sara E., et al. “Prevalence of obesity among US workers and associations with occupational factors.” American journal of preventive medicine3 (2014): 237-248. (Link)
  6. The U.S. Bureau of labor Statistics. (2013).Employed persons by detailed industry and age. Retrieved from http://www.bls.gov/cps/industry_age.htm (Link)


Help our cause


Sleep apnea blog

This sleep apnea blog was started to provide updated, accurate medical information about sleep apnea. Too many websites online have incorrect or outdated information about sleep apnea. So this sleep apnea blog was made to help counter some of the other information out there and provide a resource for other websites. Have you enjoyed our sleep apnea blog? Let us know.