Guns, Suicide, COPD and Sleep

Within the past year two tragic events, the shootings in Las Vegas and Florida have renewed the debate about guns. The politics and the money that fuels the political debate have sharply divided politicians. As tragic as these mass shootings are, deaths by suicide far outnumber the loss of live in these shootings. In 2014 suicide was the tenth most common cause of death with 42,826 lives lost (1). Half of the suicides were by firearm (21,386).

The medical profession has traditionally been reluctant to speak about politically sensitive issues such as abortion, sexuality, and guns. However, beginning early in this millennium some medical societies such as the American Academy of Pediatrics, the US Preventative Services Task Force and even the Department of Veterans Affairs were suggesting physicians ask patients about gun behavior, but a few patients complained (2-5). There were some anecdotal reports of patients feeling “pressured” to answer questions about guns (5). One grumbled that it was invasion of privacy. The National Rifle Association also viewed the medical community’s gun-related questions as discriminatory and a form of harassment. In 2011, the Republican-controlled Florida legislature, with the support of the then and still state’s Republican governor, Rick Scott, passed restrictions aimed at limiting physician inquiries about gun ownership and gun habits. Under the law, doctors could lose their licenses or risk large fines for asking patients or their families about gun ownership and gun habits. Fortunately, this law was struck down by the 11th U.S. Circuit Court of Appeals (5). The Court ruled in 10-1 decision that the law violated the First Amendment rights of doctors and did nothing to infringe on the Second Amendment right to bear arms.

Eight health professional organizations and the American Bar Association have released a call for action to reduce firearm-related injury and death in the United States (6). Specific recommendations include the following:

• Criminal background checks should be a universal requirement for all gun purchases or transfers of ownership.
• Opposition to state and federal mandates interfering with physician free speech and the patient–physician relationship, such as laws preventing physicians from discussing a patient's gun ownership.
• All persons who have a mental or substance use disorder should have access to mental health care, as these conditions can play a significant role in firearm-related suicide.
• Recognition that blanket reporting laws requiring healthcare providers to report patients who show signs of potentially causing serious harm to themselves or others may stigmatize persons with mental or substance use disorders and create barriers to treatment. The statement urges that such laws protect confidentiality, do not deter patients from seeking treatment, and allow restoration of firearm purchase or possession in a way that balances the patient's rights with public safety.
• There should be restrictions for civilian use on the manufacture and sale of large-capacity magazines and military-style assault weapons, as private ownership of these represents a grave danger to the public.

Our national professional societies including the American Thoracic Society, the American College of Chest Physicians and the Society of Critical Care Medicine have all endorsed this call for action to gun violence (7).

Editors of the Annals of Internal Medicine have recently urged physicians to sign a formal pledge committing to having conversations with their patients about firearms (8). The Annals campaign began in the wake of the Las Vegas shooting and gained momentum after the February 14 school shooting in Parkland, Florida. So far nearly 1000 physicians have signed the pledge (9).

People who commit firearm violence against themselves or others often have notable risk factors that bring them into contact with physicians. We in the pulmonary, critical care and sleep communities are positioned to prevent some of these deaths. Patients with chronic diseases including COPD and sleep deprivation are known to be at higher risks for suicide (10,11). By inquiring about guns during these patients’ clinic visits, we may be able to identify potential problems and prevent some deaths.

It is ironic, but hardly surprising, that Florida, a state known for a series of gun-rights laws and its “Stand Your Ground” self-defense law (5), is the site of the latest mass shooting. The shooter, Nikolas Cruz, by all descriptions could have readily been recognized as a potential threat. Perhaps if he had been identified and an intervention performed before the Florida law banning physicians from discussing guns when the he was 12, a tragedy could have been avoided. As Florida Sen. Marco Rubio recently found out, the times may be changing (12). Politicians should keep their politics out of the clinic, hospital and physician-patient relationship. Those who do not, and especially those who by their actions put our patients in peril, do so at their own political risk.

Richard A. Robbins, MD

Editor, SWJPCC

References

1. Centers for Disease Control and Prevention. Suicide and self-inflicted injury. March 17, 2017. Available at: https://www.cdc.gov/nchs/fastats/suicide.htm (accessed 3/2/18).
2. American Academy of Pediatrics. Gun violence prevention. Available at: https://www.aap.org/en-us/advocacy-and-policy/federal-advocacy/pages/aapfederalgunviolencepreventionrecommendationstowhitehouse.aspx (accessed 3/2/18).
3. United States Preventive Services Task Force. Guide to clinical preventive services. Available at: https://www.ataamerica.com/arc1/users/pdfforms/Guide%20to%20Clinical%20Preventive%20Services.pdf (accessed 3/2/18).
4. Department of Veterans Affairs. Firearms and dementia. August 2017. Available at: https://www.va.gov/vhapublications/ViewPublication.asp?pub_ID=2731 (accessed 3/2/18).
5. Alvarez L. Florida doctors may discuss guns with patients, court rules. NY Times. February 16, 2017. Available at: https://www.nytimes.com/2017/02/16/us/florida-doctors-discuss-guns-with-patients-court.html (accessed 3/2/18).
6. Weinberger SE, Hoyt DB, Lawrence HC 3rd, et al. Firearm-related injury and death in the United States: a call to action from 8 health professional organizations and the American Bar Association. Ann Intern Med. 2015 Apr 7;162(7):513-6. [CrossRef] [PubMed]
7. American College of Physicians. More than two dozen organizations join call by internists and others for policies to reduce firearm injuries and deaths in U.S. ACP Newsroom. May 1, 2015. Available at: https://www.acponline.org/acp-newsroom/more-than-two-dozen-organizations-join-call-by-internists-and-others-for-policies-to-reduce-firearm (accessed 3/2/18).
8. Wintemute GJ. What you can do to stop firearm violence. Ann Intern Med. 2017 Dec 19;167(12):886-7. [CrossRef] [PubMed]
9. Frellick M. More than 1000 doctors pledge to talk to patients about guns. Medscape. March 1, 2018. Available at: https://www.medscape.com/viewarticle/893307?nlid=121033_4502&src=wnl_dne_180302_mscpedit&uac=9273DT&impID=1572032&faf=1 (accessed 3/2/18).
10. Goodwin RD. Is COPD associated with suicide behavior? J Psychiatr Res. 2011 Sep;45(9):1269-71. [CrossRef] [PubMed]
11. Sleep Disorders and Sleep Deprivation: An Unmet Public Health Problem. Institute of Medicine (US) Committee on Sleep Medicine and Research; Colten HR, Altevogt BM, editors. Washington (DC): National Academies Press (US); 2006. [CrossRef] [PubMed]
12. Associated Press. Sen. Marco Rubio changes stance on high-capacity magazines after Florida school shooting. Time. February 22, 2018. Available at: http://time.com/5171653/marco-rubio-large-capacity-magazine-parkland-shooting/ (accessed 3/2/18).

Cite as: Robbins RA. Guns, suicide, COPD and sleep. Southwest J Pulm Crit Care. 2018;16(3):138-40. doi: https://doi.org/10.13175/swjpcc039-18 PDF

Saving Lives or Saving Dollars: The Trump Administration Rescinds Plans to Require Sleep Apnea Testing in Commercial Transportation Operators

In another move favoring business interests and against the common good, the Trump administration’s Department of Transportation announced recently that they are rescinding plans to require testing for obstructive sleep apnea (OSA) in train and commercial motor vehicle operators (1). As exemplified by its withdrawal from the Paris climate accords, this decision is another example of how the current administration disregards scientific findings and present-day events in establishing policy that will be detrimental to Americans.

Let us step back for a moment and briefly review the evidence that the Trump administration has ignored.

• It is well established that obstructive sleep apnea (OSA) can result in daytime sleepiness (2) and that sleepiness is detrimental to safe operation of a train or motor vehicle.
• Many studies have established that persons with OSA have an increased risk of motor vehicle crashes (3).
• Studies in commercial truck drivers have observed that this population has a high prevalence of OSA (4).
• It is estimated that OSA costs the American economy $150 billion annually (5).
• There now are relatively easy and inexpensive protocols to screen high risk individuals for OSA (4).
• Obstructive sleep apnea is a treatable condition, and treatment mitigates OSA impairment in sleepiness and reduces crash risk (6,7). In contrast, non-compliance with treatment is associated with a five-fold increase in crash risk (6).
• The costs of diagnosis and treatment are much lower than the costs that ensue when OSA persists untreated (5). For example, significant healthcare savings result from successful treatment of truck drivers (8).
• Failure to recognize and treat OSA has resulted in several high-profile transportation accidents. The following are some recent incidents:
  • September 2016: A commuter rail train slammed into the station at Hoboken, NJ killing a female bystander and leaving a child without a mother. The engineer had undiagnosed severe OSA (9).
  • December 2013: A Metro North commuter rail engineer fell asleep and his train sped around a curve resulting in a crash that killed 4 and injured 70 (10). The National Transportation Safety Board determined that undiagnosed severe OSA was the probable cause of the accident. The lack of a policy which required sleep disorder screening was further determined to be a contributing factor (11).
  • September 2013: A Greyhound bus overturned on Interstate 70 because the driver fell asleep resulting in multiple injuries. The driver was later found to have untreated OSA (12).
  • June 2009: A tractor-trailer traveling at a high speed did not see stopped cars ahead on Interstate 44 resulting in a crash that killed 10 and injured 6. It was later determined that the truck driver had mild OSA contributing to fatigue (13).

Despite the weight of the aforementioned evidence, the current administration has chosen to ignore it in favor of letting private industry regulate itself implying the current regulations are sufficient. As illustrated by the incidents cited above, recent events have proven them wrong. As Sir Winston Churchill once said “Those who fail to learn from history are doomed to repeat it”. Continuing with the current policy will inevitably result in further preventable disasters and more loss of life.

What can be done? At the federal level, one should consider advocating to your own congressional representatives for reconsideration of this poorly considered policy. On a personal level, federal policy is ultimately guided by the “ballot box”, which is something to consider for the next election. Finally, be aware that the next time you are driving down the interstate, the truck or bus driver approaching you from behind may have untreated OSA!

Stuart F. Quan, M.D.^1,2, Laura K. Barger, Ph.D.¹, Matthew D. Weaver, Ph.D.¹, and Charles A. Czeisler, Ph.D., M.D.¹

¹Division of Sleep and Circadian Disorders

Brigham and Women’s Hospital

Harvard Medical School, Boston, MA USA

²Asthma and Airway Disease Research Center

University of Arizona College of Medicine

Tucson, AZ USA

References

1. Federal Register. Evaluation of safety sensitive personnel for moderate-to-severe obstructive sleep apnea. Last updated: 2017. Available at: https://federalregister.gov/d/2017-16451 (Accessed: August 10, 2017)
2. Committee on Sleep Medicine and Research Board on Health Sciences Policy. Sleep disorders and Sleep Deprivation--An Unmet Public Health Problem. Washington, D.C.: National Academies Press, 2006; 404.
3. Tregear S, Reston J, Schoelles K, Phillips B.Obstructive sleep apnea and risk of motor vehicle crash: systematic review and meta-analysis. J Clin Sleep Med. 2009 Dec 15;5(6):573-81. [PubMed]
4. Kales SN, Straubel MG.Obstructive sleep apnea in North American commercial drivers. Ind Health. 2014;52(1):13-24. [CrossRef] [PubMed]
5. Anonymous. Hidden health crisis costing America billions. Underdiagnosing and undertreating obstructive sleep apnea draining healthcare system. Last updated: 2016. Available at: http://www.aasmnet.org/sleep-apnea-economic-impact.aspx (Accessed: August 15, 2017)
6. Burks SV, Anderson JE, Bombyk M, et al. Nonadherence with employer-mandated sleep apnea treatment and increased risk of serious truck crashes. Sleep. 2016 May 1;39(5):967-75. [CrossRef] [PubMed]
7. Tregear S, Reston J, Schoelles K, Phillips B.Continuous positive airway pressure reduces risk of motor vehicle crash among drivers with obstructive sleep apnea: systematic review and meta-analysis. Sleep. 2010 Oct;33(10):1373-80. [CrossRef] [PubMed]
8. 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 motor vehicle driver population. J Occup Environ Med. 2010 May;52(5):473-7. [CrossRef] [PubMed]
9. Anonymous Hoboken train crash investigation hampered by heavy damage. CBS News. 2016; Available at: http://www.cbsnews.com/news/hoboken-train-crash-investigation-hampered-heavy-damage/ (Accessed: August 15, 2017)
10. Anonymous. December 2013 Spuyten Duyvil derailment. Last updated: 2017. Available at: https://en.wikipedia.org/wiki/December_2013_Spuyten_Duyvil_derailment (Accessed: August 10 , 2017)
11. National Transportation Safety Board. ​Metro-North Railroad Derailment. Last updated: 2014. Available at: https://www.ntsb.gov/investigations/AccidentReports/Pages/RAB1412.aspx (Accessed: August 15, 2017)
12. Lee D.  Sleep Test Leads to $6M Greyhound Settlement. Last updated: 2016. Available at: http://oldarchives.courthousenews.com/2016/03/09/sleep-test-leads-to-6m-greyhound-settlement.htm (Accessed: March 9, 2017)
13. National Transportation Safety Board. Highway Accident Report: Truck‐Tractor Semitrailer Rear‐End Collision Into Passenger Vehicles on Interstate 44 Near Miami, Oklahoma June 26, 2009. Last updated: 2010. Available at: https://www.ntsb.gov/investigations/AccidentReports/Reports/HAR1002.pdf (Accessed: August 10, 2017)

Cite as: Quan SF, Barger LK, Weaver MD, Czeisler CA. Saving lives or saving dollars: The Trump administration rescinds plans to require sleep apnea testing in commercial transportation operators. Southwest J Pulm Crit Care. 2017;15:84-6. doi: https://doi.org/10.13175/swjpcc102-17 PDF 

Disclosures 

Editor's note: In 2016 Dr. Quan authored an editorial titled "Screening for Obstructive Sleep Apnea in the Transportation Industry—The Time is Now" in SWJPCC. The editorial encouraged screeening of transportation workers for sleep apnea.

Screening for Obstructive Sleep Apnea in the Transportation Industry—The Time is Now

Stuart F. Quan, M.D.

Division of Sleep and Circadian Disorders

Brigham and Women’s Hospital

and

Division of Sleep Medicine

Harvard Medical School

Boston, MA USA

and

Asthma and Airway Disease Research Center

University of Arizona College of Medicine,

Tucson, AZ USA

On September 29, 2016, a New Jersey Transit train failed to slow down and stop at the station in Hoboken, New Jersey. The resulting crash injured a number of passengers and killed a young mother who happened to be near the crash site. Subsequently, it was learned that the train engineer who apparently had blacked out was diagnosed as having severe obstructive sleep apnea (OSA) (1). Unfortunately, this was not an isolated incident. Over the past few years, there have been several other well-documented incidents of train, truck and bus crashes resulting from their operators falling asleep from OSA. In 2013, a Metro-North commuter train derailed outside of New York City because of excessive speed approaching a curve, the train engineer reported being “dazed” and was subsequently found to have OSA (2). Four passengers were killed and numerous others were injured. In another well-documented accident in 2013, the driver of a Greyhound bus fell asleep. The bus ran off the road, rolled on its side and injured 35 passengers. The driver had been told to get tested for OSA, but did not have the study done. A subsequent court-ordered polysomnogram showed OSA (3). In another incident in 2009, a truck-tractor semitrailer operator failed to notice slowing and stopped cars in front of him and collided with a passenger vehicle. This led to a series of rear end vehicle collisions resulting in 10 fatalities. The cause of the accident was operator fatigue related in part to OSA (4). These well-publicized incidents are only a few of the sleepiness/fatigue related accidents caused by unrecognized OSA in the transportation industry.

One of the most common symptoms attributed to OSA is daytime sleepiness which can be uncontrollable and unpredictable. Numerous studies have demonstrated that persons with OSA have an increased rate of motor vehicle accidents with up to a 4.9 fold higher risk (5). Accidents involving only a single vehicle are particularly frequent suggesting that the crashes are caused by the operators having fallen asleep. Truck drivers are at even greater risk, most likely because they are disproportionately male, middle aged and overweight, all of which are risk factors for OSA. Over a ten year span from 2004 to 2013, it has been estimated that 3,133 to 8,952 deaths and 77,000 and 220,000 serious injuries have resulted from sleepy operators of commercial motor vehicles, many of whom most likely had undiagnosed and untreated OSA (6).

Given the severe consequences of unrecognized OSA on public safety and the high prevalence of unrecognized OSA among operators of trains, buses and commercial trucks, the imperative to screen and treat these persons for OSA is high. The advisory boards to the Federal Motor Carrier Safety Administration (FMCSA) have recommended that commercial truck drivers be screened for OSA if their body mass index is > 40 kg/m², or >33 kg/m² and have 3 or more conditions or findings associated with OSA, but adoption of these recommendations has not occurred (7). More recently, the Department of Transportation, Federal Railroad Administration and the FMCSA have taken the first steps to mandate screening and treatment of rail and commercial motor vehicle operators for OSA by soliciting public comment (8). Airline pilots are already screened. However, there is substantial opposition from the trucking industry and drivers themselves, the latter because of potential job loss. However, such a screening program in one large trucking company has demonstrated a 5 fold reduction in accident rates in drivers who were adherent to CPAP treatment for OSA (5).

With the development of relatively simple to use ambulatory devices that can identify most persons with OSA, screening for OSA can be done easily and cost-effectively. In the vast majority of cases, referral to a sleep lab is not necessary. Persons diagnosed with OSA can be treated with several different modalities and are able to return to work. Employers may actually experience a reduction in their costs related to fewer accidents and improved employee health. Thus, there is no reason to delay requiring OSA screening programs for all persons working in occupations where public safety is at risk. For regulators, policy makers, and the various industries affected, the time is now. Failure to act places the responsibilities for the ensuing economic costs, injuries and deaths on your shoulders.

References

1. Marsh R, Shortell D. NJ. Train Engineer in Crash had Undiagnosed Sleep Apnea. CNN. October 17, 2016. Available at: http://www.cnn.com/2016/11/17/us/njt-engineer-sleep-apnea/ (accessed 12/2/16).
2. National Transportation Safety Board. Metro-North Railroad Derailment. October 24, 2014. Available at: http://www.ntsb.gov/investigations/accidentreports/pages/RAB1412.aspx (accessed 12/2/16).
3. Five Passengers hurt in 2013 Greyhound Bus Crash Win $6 Million Settlement Attorneys Say. WCPO Cincinnati. http://www.wcpo.com/news/local-news/hamilton-county/cincinnati/five-passengers-hurt-in-2013-greyhound-bus-crash-win-6-million-settlement-attorneys-say (accessed 12/2/16).
4. National Transportation Safety Board. Truck-Tractor Semitrailer Rear-End Collision Into Passenger Vehicles on Interstate 44. September 28, 2010. http://www.ntsb.gov/investigations/AccidentReports/Pages/HAR1002.aspx (accessed 12/2/16).
5. Tregear S, Reston J, Schoelles K, Phillips B. Obstructive sleep apnea and risk of motor vehicle crash: systematic review and meta-analysis. J Clin Sleep Med. 2009;5 (6):573–81.[PubMed]
6. Burks SV, Anderson JE, Bombyk M, et al. Nonadherence with Employer-Mandated Sleep Apnea Treatment and Increased Risk of Serious Truck Crashes. Sleep. 2016 May 1;39(5):967-75. [CrossRef] [PubMed]
7. Miller E. FMCSA Medical Review Board Issues Sleep Apnea Guidelines. Transport Topics. August 24, 2016. Available at:  http://www.ttnews.com/articles/basetemplate.aspx?storyid=42963&page=1 (accessed 12/2/16).
8. Federal Motor Carrier Safety Administration. U.S. DOT Seeks Input on Screening and Treating Commercial Motor Vehicle Drivers and Rail Workers with Obstructive Sleep Apnea. March 8, 2016. Available at: https://www.fmcsa.dot.gov/newsroom/us-dot-seeks-input-screening-and-treating-commercial-motor-vehicle-drivers-and-rail-workers (accessed 12/2/16).

Cite as: Quan SF. Screening for obstructive sleep apnea in the transportation industry—the time is now. Southwest J Pulm Crit Care. 2016;13(6):285-7. doi: https://doi.org/10.13175/swjpcc132-16 PDF

The Hefty Price of Obstructive Sleep Apnea

Reference as: Budhiraja R. The hefty price of sleep apnea. Southwest J Pulm Crit Care 2011;3:169-71. (Click here for a PDF version)

Obesity is approaching an epidemic level in the United States. The association between obesity and obstructive sleep apnea (OSA) is quite strong and likely causal. Approximately half of obese individuals have OSA and the risk of OSA increases with increasing BMI. Conversely, majority of individuals with OSA are obese. However, whether this relationship is bidirectional and OSA can, in turn, contribute to obesity is unclear.

The study by Brown and colleagues in the Journal attempts to answer this question ¹. The authors analyzed prospectively obtained data from a large community-based cohort and found that the participants with more severe sleep disordered breathing at baseline demonstrated a modest increase in body mass index (BMI) over a 5 year follow up period.

What can these intriguing results be attributed to? Pathophysiology of obesity is a multifactorial and complex process and may include dietary, lifestyle and genetic components.  As the authors hypothesize, an alteration in leptin-ghrelin levels in OSA may contribute to obesity. However, independent effect of sleep apnea on these metabolic hormones is still not clear. Studies in OSA, in contrast to those with sleep deprivation, actually suggest increased daytime leptin levels, primarily explained by obesity ². Similarly, contradictory data exist regarding ghrelin levels in OSA. While some studies demonstrate an increase in ghrelin levels ^{3, 4}, others do not ^{5, 6}. A decrease in energy expenditure is a plausible mechanism whereby OSA may lead to further weight gain. It is easily fathomable that disturbed sleep in obese people may contribute to daytime fatigue and lethargy and promote a more sedentary lifestyle.  However, convincing data from large studies confirming such an association is again lacking. Finally, an altered feeding behavior with a preference for a weight-gain promoting diet may be seen in sleep disordered breathing and contribute to obesity ⁷.

The strengths of this study include a large sample size derived from community-based cohorts, prospective collection of data and objective documentation of sleep abnormalities. However, the readers should bear in mind that the adjusted increase in BMI was fairly modest- in order of 0.21 kg/m² in those with mild OSA and 0.51 kg/m² in moderate to severe OSA. Furthermore, the statistical models used in the study accounted for only 7% of the total variance, suggesting that the factors not included in analysis likely played a prominent role in the weight gain.

Nevertheless, this study adds to emerging literature suggesting SDB as a risk factor for weight gain ^{8, 9}. Ideally, these data suggest need for well conducted prospective studies looking at physical activity, diet and change in BMI in patients with SDB. However, in view of the now well recognized adverse effects of severe sleep apnea, it will not be feasible to conduct long-term studies in these patients without offering treatment.  The other line of evidence that would support the hypothesis that sleep apnea predisposes to weight gain, would be weight loss with adequate therapy. Indeed some studies have assessed this, but with variable results ^10-12. Some of the factors underlying such variability in results may include differences in dietary habits, physical exercise, age of the participants, sleep duration, use of medications and presence of additional comorbidities ¹³. Future studies, apart from controlling for these variables, should also consider evaluating changes in central obesity instead of, or in addition to BMI, as the former may be a better marker of adverse cardiovascular outcomes than BMI ¹⁴.

Finally, obesity is a risk factor for an array of cardiovascular and metabolic adverse outcomes. This study provides further rationale to add abnormal sleep to unhealthy diet and lack of exercise as crucial factors that need to be modified to curb the obesity epidemic. Further longitudinal and interventional studies are required to help confirm these observations and assess the impact of better sleep on health outcomes.

Rohit Budhiraja, M.D.^{1, 2, 3}

Associate Editor

Southwest Journal of Pulmonary and Critical Care 

¹ Department of Medicine, Southern Arizona Veterans Affairs Health Care System (SAVAHCS) , Tucson, AZ

² Arizona Respiratory Center, The University of Arizona, Tucson, AZ

³ Department of Medicine, University of Arizona College of Medicine, Tucson, AZ

Corresponding Author:

Rohit Budhiraja, MD

Southern Arizona VA HealthCare System,

3601 S 6^th Ave,

Tucson, Arizona 85723

rohit.budhiraja@va.gov

Phone: 520-331-2007

Fax: 520-629-4641

References

1. Brown MA, Goodwin JL, Silva GE et al. The Impact of Sleep-Disordered Breathing on Body Mass Index (BMI): The Sleep Heart Health Study (SHHS). Southwest J Pulm Crit Care 2011;3:159-68.
2. Sánchez-de-la-Torre M , Mediano O, Barceló A et al. The influence of obesity and obstructive sleep apnea on metabolic hormones. Sleep Breath 2011 Sep 13. [Epub ahead of print]
3. Harsch IA, Konturek PC, Koebnick C et al. Leptin and ghrelin levels in patients with obstructive sleep apnoea: effect of CPAP treatment. Eur Respir J. 2003;22:251–7.
4. Takahashi K, Chin K, Akamizu T et al. Acylated ghrelin level in patients with OSA before and after nasal CPAP treatment. Respirology 2008;13:810–6.
5. Ulukavak Ciftci T, Kokturk O, Bukan N et al. Leptin and ghrelin levels in patients with obstructive sleep apnea syndrome. Respiration 2005;72:395–401.
6. Papaioannou I, Patterson M, Twigg GL et al. Lack of association between impaired glucose tolerance and appetite regulating hormones in patients with obstructive sleep apnea. J Clin Sleep Med 2011; 7:486-92B.
7. Vasquez MM, Goodwin JL, Drescher AA, Smith TW, Quan SF. Associations of dietary intake and physical activity with sleep disordered breathing in the apnea positive pressure long-term efficacy study (APPLES). J Clin Sleep Med 2008; 4:411-8.
8. Traviss KA, Barr SI, Fleming JA, Ryan CF. Lifestyle-related weight gain in obese men with newly diagnosed obstructive sleep apnea. J Am Diet 2002;102:703-6.
9. Phillips BG, Hisel TM, Kato M et al. Recent weight gain in patients with newly diagnosed obstructive sleep apnea. J Hypertens 1999;17:1297-300.
10. Chin K, Shimizu K, Nakamura T et al. Changes in intra-abdominal visceral fat and serum leptin levels in patients with obstructive sleep apnea syndrome following nasal continuous positive airway pressure therapy. Circulation 1999;100:706–71.
11. Loube DI, Loube AA, Erman MK. Continuous positive airway pressure treatment results in weight loss in obese and overweight patients with obstructive sleep apnea. J Am Diet Assoc 1997; 97:896–7.
12. Redenius R, Murphy C, O'Neill EO, al-Hamwi M, Zallek SN. Does CPAP lead to BMI? J Clin Sleep Med 2008;4:205–9.
13. Quan SF, Budhiraja R, Parthasarathy S. Is There a Bidirectional Relationship Between Obesity and Sleep-Disordered Breathing? J Clin Sleep Med 2008;4: 210–211.
14. Lee CM, Huxley RR, Wildman RP, Woodward M. Indices of abdominal obesity are better discriminators of cardiovascular risk factors than BMI: a meta-analysis. Journal of Clinical Epidemiology 2008; 61: 646-653.