J6

Oretce

R

D

S

o

Oral Maxillofac Surg6:968-972, 2008

Quality of Life Evaluation ofMaxillomandibular Advancement Surgeryfor Treatment of Obstructive Sleep Apnea

Kok Weng Lye, BDS, MDS,* Peter D. Waite, MPH, DDS, MD,†

Dan Meara, DMD, MD,‡ and Deli Wang, PhD§

Purpose: The purpose of this study was to investigate the quality of life (QOL) for patients whounderwent maxillomandibular advancement (MMA) surgery for obstructive sleep apnea (OSA) treatmentusing the Functional Outcomes of Sleep Questionnaire (FOSQ). Correlation of the findings with param-eters from the polysomnograph (PSG) and physical examination were also performed. No QOL studieshave been carried out for MMA in OSA, and the FOSQ is the most appropriate method.

Patients and Methods: The FOSQ instrument is a survey designed to evaluate QOL in OSA and provento be effective. All patients followed a standard prospective protocol of pre- and 6 months postoperativedata collection. Clinical radiographs, PSG, FOSQ, endoscopy, and computed tomography scans wereanalyzed.

Results: Fifteen patients with complete data were included in the study. There was minimal change inthe BMI from a preoperation mean of 32.10 to 31.50 at 6 months postoperation. The operation was 86.7%(13 of 15) successful (postoperative apnea and hypopnea index [AHI] decreased by 50% and was �20),with a significant decrease of the mean preoperation apnea-hypopnea index (AHI) of 69.12 to 13.87postoperation (P � .0001). The minimum oxygen saturation (Lsat) correspondingly increased from amean of 76.49 to 84.96 (P � .0001). A total of 93.3% of our patients achieved a successful QOL changebased on a FOSQ score of greater than or equal to 18. There was statistically significant changes in alldomains; general productivity (P � .0003), social outcome (P � .0020), activity level (P � .0008), vigilance(P � .0028), intimacy and sex (P � .0039), and the total score (P � .0002) postoperatively. Changes of Lsatand AHI were highly correlated (r � �0.728, P � .002). The magnitude of the Le Fort advancement was alsofound to be negatively correlated to the change in AHI (r � �0.544, P �.036). There was no correlationbetween the FOSQ scores and all other parameters, including both the PSG parameters (AHI and Lsat).

Conclusion: MMA remains the most effective operation for the treatment of OSA and yet no QOLstudies have been carried out. The disease-specific QOL instrument (FOSQ) showed the subjectivefunctional improvement in MMA patients. QOL instruments should be used for all surgical basedtreatment as they add a new dimension to the assessment of the patient and procedures.© 2008 American Association of Oral and Maxillofacial Surgeons

J Oral Maxillofac Surg 66:968-972, 2008

aw

aim

t

t

5

k

©

0

bstructive sleep apnea (OSA) in adults is fast gainingecognition as a serious breathing disorder with anstimated prevalence in middle-aged males of be-ween 1.3% to 4%.1,2 This percentage could realisti-ally be even higher in view of the fact that these 2pidemiologic studies were done more than 13 years

eceived from the University of Alabama, Birmingham, Birmingham, AL.

*Fellow, Department of Oral and Maxillofacial Surgery, School of

entistry.

†Professor and Chairman, Department of Oral and Maxillofacial

urgery, School of Dentistry.

‡Resident, Department of Oral and Maxillofacial Surgery, School

f Dentistry.

§Assistant Professor, Medical Statistics Section, Division of Hema- d

968

go and the average body mass index (BMI) in firstorld countries has been increasing.Patients with OSA suffer from sleep fragmentation

nd deprivation due to the multiple arousals and annability to achieve sufficient deep and rapid eye

ovement (REM) sleep. The poor sleep pattern

ology/Oncology, Department of Medicine, School of Medicine.

Address correspondence and reprint requests to Dr Lye: Na-

ional Dental Centre, Department of Oral and Maxillofacial Surgery,

Second Hospital Avenue, Singapore 168938, Singapore; e-mail:

okwenglye@yahoo.com

2008 American Association of Oral and Maxillofacial Surgeons

278-2391/08/6605-0021$34.00/0

oi:10.1016/j.joms.2007.11.031

c9twporsqtnatp

nkmadTta4alociomO

Q

mabfivdtTisqC(nIShs

aafmAtTa2tsiti

tt

M

oOoavdrsybstoe

S

tafintag

P

tim

LYE ET AL 969

auses excessive daytime sleepiness (EDS) in almost0% of the affected.3 EDS has been shown to lead toraffic accidents,4 cognitive impairment that affectsork productivity,5 and behavioral changes such asoor memory, difficulty in concentration and carryingut everyday tasks, irritability, depression, and eveneduced libido or impotence.3 The accompanyingnoring has also been shown to affect the spouse’suality of life (QOL).6,7 Physiologically, OSA increaseshe risk of severe medical complications as a result ofocturnal hypoxia and hypercapnia. These includerrhythmias, heart failure, ischemic heart disease, sys-emic and pulmonary hypertension, neurologic com-lications, and even mortality.8-10

The diagnosis of OSA is undertaken via an over-ight sleep study in a monitored sleep facility,11 alsonown as polysomnography (PSG). The disease iseasured and categorized using a few commonly

dopted parameters such as the apnea-hypopnea in-ex (AHI) and the lowest oxygen saturation (Lsat).herefore traditionally, the efficacy of sleep apnea

reatment is measured by the reduction of the AHInd improvement of the Lsat. A study showed that0% of the trials for OSA used only these parametersnd did not examine patients’ symptoms or quality ofife outcomes.12 AHI does not correlate with QOLutcomes, so by itself the index may not be suffi-ient.13,14 Because the main motivation for treatments quality of life, there should be routine measurementf these outcomes. QOL was included as an outcomeeasure in only 25% of the 95 clinical trials involvingSA.12

uality of Life Assessment

It has been quoted that “Quality of life in clinicaledicine represents the functional effect of an illness

nd its consequent therapy on a patient, as perceivedy the patient.”15 It has been a neglected dimensionor many diseases as physicians have often been treat-ng patients based on test results. Today, QOL isalued as an important aspect of patient care. QOL isone by assessing the various domains or componentshat make up the overall well-being of the patient.here are general and disease specific quality of life

nstruments available. There are several validated OSApecific instruments that have been used to assess theuality of life for patients with OSA, including thealgary Sleep Apnea Quality of Life InstrumentSAQLI), the Functional Outcomes of Sleep Question-aire (FOSQ), the OSA Patient Oriented Severityndex (OSAPOSI), and Franco’s Pediatric Obstructiveleep Apnea Questionnaire (OSA-18).16 The OSAPOSIas been renamed the Symptoms of Nocturnal Ob-

truction and Related Events (SNORE 25).17 (

The FOSQ, developed by Weaver et al,18 is a self-dministered disease specific instrument designed tossess the impact of excessive sleepiness on daytimeunction and to quantify improvement after treat-ent. It measures the QOL of the patients in terms of:ctivity Level, Vigilance, Intimacy and Sexual Rela-

ionships, General Productivity, and Social Outcome.he different domain scores were added to computetotal score ranging from 5 (maximal dysfunction) to0. According to the authors that developed the ques-ionnaire, a total score greater than or equal to 18hows a normal functional status. This is also reflectedn the mean score of a group of normal individualsested18; (89.59/5 � 17.92 because of the new scor-ng system).

There are few studies in the literature that examinehe change in QOL of patients who undergo surgeryo treat OSA.17,19

axillomandibular Advancement

Maxillomandibular advancement surgery (MMA) isne of the most efficacious surgical procedures forSA. It was first suggested as an alternative to trache-tomy for the treatment for OSA in 1979.20 MMAdvocated by Riley and Powell meant a 10 mm ad-ancement of the maxilla and mandible.21 The coor-inated advancement of the maxilla and mandibleesults in retropalatal and retrolingual airway expan-ion.22,23 The literature shows that this surgeryielded a 90% to 100% cure rate for the OSA21,24-26

ased on AHI but there have not been any QOLtudies for this procedure. Therefore, the inclusion ofhis additional dimension in the research of MMA andther surgical treatment will provide valuable knowl-dge in the management of OSA.

tudy Aim

The aim of this study is to measure the change inhe QOL of patients undergoing maxillomandibulardvancement (MMA) surgery. This change is quanti-ed by the Functional Outcome of Sleep Question-aire (FOSQ). The correlation of QOL improvemento other parameters such as PSG parameters, themount of advancement during the orthognathic sur-ery and change in BMI was carried out.

atients and Methods

We recruited consecutive OSA patients that wereo undergo MMA at the Department of Oral and Max-llofacial Surgery (OMS), University of Alabama, Bir-

ingham (UAB) for this Institutional Review Board

IRB)-approved study.

pawccp

apsmdptvaDm

mtpeoandgwemostcuwta

ma

R

ac2Ca

mapp�acseip

as

amsptvcvot4

(6

GSAVIT

L

970 FOSQ AND MMA

The inclusion criteria were: 1) patients with com-lete clinical, PSG, FOSQ, and radiographic records,nd 2) patients who were treated with MMA with orithout other adjunctive procedures. The exclusion

riteria were: 1) patients who were still on nasalontinuous positive airway pressure (nCPAP), and 2)atients who had permanent tracheostomy.Each patient’s demographic data including weight

t preoperation and 6 months postoperation, pre- andostoperation PSG and FOSQ findings, types of theurgical procedures, and the amount of advance-ent achieved were noted according to the stan-

ard protocol of the clinic. The FOSQ was com-leted by each patient before the operation and 4o 6 months postoperation. The magnitude of ad-ancement was measured from pre- and postoper-tive lateral cephalographs using the Planmecaimaxis Imaging Software (Dimaxis Pro 4.1X, Plan-eca, Helsinki, Finland).

STATISTICAL ANALYSIS

Descriptive statistics were used to describe de-ographic variables and interested parameters of

he samples from the study patient population. Theaired t test was used to compare pre- and postop-ration changes of clinical variables and parametersf quality of life that satisfy the normal distributionssumption. For variables that were not distributedormally, the sign rank test was used to test pairedifference between pre- and postoperation. The 2roup t test was used to compare variables thatere categorized into different groups, eg, differ-

nce of advancement of the Le Fort I osteotomy,ovement for the mandibular bilateral sagittal split

steotomy (BSSO), change of AHI or Lsat or FOSQcores between the operation successful group andhe unsuccessful group. Associations among clini-al parameters and FOSQ variables were evaluatedsing Pearson correlation coefficients. The �2 testas applied to compare proportion difference be-

ween 2 groups. The Bonferroni correction was

Table 1. COMPARING PRE- AND POSTOPERATIVE FOSQ

FOSQPreoperation Mean

(range)

eneral productivity 3.10 (2-3.88)ocial outcome 3.00 (1-4)ctivity level 2.70 (1.33-3.89)igilance 3.56 (1.29-3.29)

ntimacy and gender 3.05 (1-4)otal score 14.40 (8.23-18.53)

Abbreviation: FOSQ, Functional Outcomes of Sleep Questionnai

ye et al. FOSQ and MMA. J Oral Maxillofac Surg 2008.

pplied to adjust cut-off criteria for P values due to (

ultiple comparisons in the study so that the over-ll false positive rate was controlled to be 5%.

esults

Fifteen patients who had surgery between 2005nd 2007 were identified as suitable according to theriteria. They had a mean age of 47.93 years (range,3 to 67 years). There were 13 Caucasian males and 2aucasian females. The patients had a mean preoper-tive BMI of 32.1 (range, 22.1 to 40.6).

The baseline preoperation PSG findings showed aean preoperative AHI of 69.12 (range, 18.7 to 112.00)

nd a mean Lsat of 76.49% (range, 45 to 90.6). Fourteenatients had severe sleep apnea (AHI � �30) whereas 1atient had moderate sleep apnea (AHI � �30 and15). All the patients had tried and failed nCPAP ther-

py previously and were not using it at the point ofonsultation. They also all complained of EDS and de-ired surgery to improve their daytime functioning. Sev-ral of the patients also had undergone previous surger-es like UPPP and nasal surgery for this particularroblem but without significant improvement.The preoperative FOSQ were compiled and scored

ccording to the developer’s instructions and arehown in Table 1.

All 15 patients underwent MMA and 12 patients haddditional procedures carried out, including advance-ent geniotomy, uvulopalatopharyngoplasty (UPPP),

eptoplasty, or turbinoplasty. The choice of surgicalrocedure was based on the clinical and computedomography (CT) scan findings of the airway. The ad-ancement for the MMA was also not uniform but ac-ording to individual craniofacial presentation and se-erity of OSA. The mean advancement of the Le Fort Isteotomy was 8.59 mm (range, 3.14 to 11.04 mm) andhe movement for the mandible was 8.96 mm (range,.93 to 16.59 mm).The postoperative PSG showed a mean AHI of 13.87

range, 1.7 to 52.9) and a mean Lsat of 84.96% (range,2% to 94.6%). Postoperative BMI at 6 months was 31.5

LTS

peration Mean(range) Mean Difference P Value

(3.5-4) 0.77 .0003(3-4) 0.93 .002(2.89-4.00) 0.91 .0008(2.86-4.00) 1.07 �.0001(3-4) 0.78 .0039(15.5-20.00) 4.48 .0002

RESU

Posto

3.873.933.613.643.83

18.88

re.

range, 21.9 to 39.2). All patients showed improvement

iscotssg

wctrcsA�

t�tcL

oFtcAg

D

tsBrsarta

Omaudmsa

sec

afpspf

l1Awcwt

ttntt

hThitdTrtsaeo

lptprttmtisst

LYE ET AL 971

n AHI and Lsat after the operation. However, using theuccess criteria of a postoperative AHI which had de-reased by 50% and was less than 20,27 the success ratef the operations was 86.7% (13 of 15). The postopera-ive FOSQ results are also shown in Table 1. All patientshowed improvement in their FOSQ scores, but theuccess rate, using the success criteria of total scorereater than or equal to 18, was 93.3% (14 of 15).The change in BMI from preoperation to postoperationas 0.6, which was statistically significant (P � .04). The

hanges in AHI and Lsat from preoperation to postopera-ion was �55.25 (P � .0001) and 8.47% (P � .001),espectively. Both changes were very significant statisti-ally. The improvement in FOSQ scores was statisticallyignificant for all domains and the total score (Table 1).fter Bonferroni corrections for multiple comparisons (P.05/6 � .008), they were still statistically significant.When we were looking for correlations amongst

he parameters, AHI is correlated highly to Lsat (r �0.728, P � .0021) and all the different domains of

he FOSQ were correlated highly to each other. Thehange in AHI also was correlated to the magnitude ofe Fort advancement (r � �0.54, P � .036).The change of FOSQ domain and total scores were

nly correlated to each other. The magnitude of Leort advancement was correlated to the magnitude ofhe mandibular advancement (P � .03). When weompared the cases that were successful by eitherHI or FOSQ, there was no association between the 2roups (P � 1.00).

iscussion

MMA SUCCESS

This study supports the effectiveness of MMA as areatment for obstructive sleep apnea, with an 86.7%uccess rate. Our patients had a mean preoperationMI of 32.1 and a postoperation BMI of 31.5, whichemoved the chance that the success resulted from aignificant loss of weight. The 2 patients that did notchieve success according to the AHI achieved largeeductions in their apnea index but retained persis-ent hypopneas and also showed significant centralpneas.

FOSQ

This is a disease-specific validated questionnaire forSA. It has been used in many studies looking at treat-ent with nasal CPAP27-29 and has been translated into

nother language and was still effective.30 It has beensed only in 2 surgical studies in the literature.17,19 Ourata showed very significant improvement in all do-ains after the surgery. This is similar to another

tudy.27 The use of the success criterion in our study is

novel approach. We defined success when a total a

core of greater than or equal to 18 is achieved postop-ration. Using this novel criterion, we achieved a suc-ess rate of 93.3% (14 of 15) for the operation.There was no association between the FOSQ scores

nd other parameters. This shows that the subjectiveunctioning of the patients is complex and not ex-lained easily by the parameters we routinely mea-ure. However, this does not take away the fact thatatients’ satisfaction is dependent primarily on this

actor and we cannot ignore it.It was also noticed that the patients started with a

arge range of preoperative FOSQ scores (8.23 to8.53). This does not correlate to the preoperationHI. The large variation meant that some patientsere subjectively having tremendous functional diffi-

ulties whereas others perceived only slight problemsith daytime function.3 There could be 2 reasons for

his.First, there may be a ceiling effect where the pa-

ient cannot quantify their deficits correctly becausehey never experienced a better level. This could beegated if another preoperation survey is carried outogether with the postoperation questionnaire whenhey know how much better they can actually get.

Second, this could mean that OSA has 2 unrelatedealth consequences: physiologic injury and the EDS.he physiologic injury is due mainly to a hypoxemia/ypoxia mechanism, thus we should be concentrat-

ng on oxygen desaturation parameters like the totalime below certain oxygen saturation, the number ofesaturations, and the average degree of desaturation.he EDS is not due primarily to the desaturation butather the disturbance in sleep pattern and the reduc-ion or elimination of deep (stages 3, 4) and REMleep. For this aspect of sleep apnea, we should lookt the sleep pattern changes including: the amount ofach stage of sleep, the number of cycles, and lengthf each cycle.

AHI VERSUS FOSQ

The AHI index correlates highly to the Lsat and isogically linked to physiologic changes such as bloodressure31-33 but it does not give any clear bearing onhe sleep quality. In contrast, FOSQ is reflective of theatients’ ability to function and would be affected di-ectly by EDS. Our results support this difference ashere is no correlation between the PSG parameters andhe FOSQ scores. Even when we focus on the achieve-ent of “success” by both AHI and FOSQ total score,

here was no association (P � 1.000). Thus, our datandicate that the AHI is discordant with the FOSQ. Othertudies in the literature also reached a similar conclu-ion.13,14 This supports our protocol and recommenda-ion that the QOL instruments are important in the

ssessment of OSA patients.

nAaIefallarircapet

ssatbbt

R

1

1

1

1

1

1

1

1

1

1

2

2

2

2

2

2

2

2

2

2

3

3

3

3

972 FOSQ AND MMA

MMA VERSUS OUTCOME

The only correlation found was between the mag-itude of the Le Fort advancement and the change inHI (r � �0.54). This implies that the larger thedvancement, the more negative a change in the AHI.t is reasonable to believe that a large advancementquates to an increase of posterior airway space. Thisact enforces the belief that severe OSA requires a largedvancement for successful management. However,arger magnitude of advancement did not show a corre-ation with FOSQ. Based on our current knowledge, were unable to decide on the amount of advancementequired to achieve surgical success for different sever-ty of OSA and different airway anatomy. Thus, furtheresearch should attempt to create a dynamic model thatan identify the areas of limitation in an airway and alsoppropriately translate any jaw advancements into ex-ansion of the airway and pressure changes. This willnable us to predict the movement necessary based onhe patients’ preoperative anatomy.

In summary, this study supports the use of MMAurgery for treatment of OSA. It produces a highuccess rate in terms of both PSG parameters as wells the subjective functional outcome via the FOSQ. Ashese measures do not coincide, it is important to useoth in the management of this disease. There shoulde more research in the future to decipher the rela-ionship between sleep quality and quality of life.

eferences1. Gislason T, Almqvist M, Boman G, et al: Prevalence of sleep

apnea syndrome among Swedish men—An epidemiologicalstudy. J Clin Epidemiol 41:571, 1988

2. Young T, Palta M, Dempsey J, et al: The occurrence of sleep-disordered breathing among middle-aged adults. New EnglJ Med 328:1230, 1993

3. Guilleminault C, Eldridge L, Tilkian A, et al: Sleep apnea syndromedue to upper airway obstruction. Arch Intern Med 137:296, 1977

4. Young T, Blustein J, Finn L, et al: Sleep-disordered breathingand motor vehicle accidents in a population based sample ofemployed adults. Sleep 20:608, 1997

5. Cheshire K, Engleman H, Deary I, et al: Factors impairingdaytime performance in patients with sleep apnea/hypopneasyndrome. Arch Intern Med 152:538, 1992

6. Parish JM, Lyng PJ: Quality of life in bed partners of patientswith obstructive sleep apnea or hypopnea after treatment withcontinuous positive airway pressure. Chest 124:942, 2003

7. Beninati W, Harris CD, Herold DL, et al: The effect of snoringand obstructive sleep apnea on the sleep quality of bed part-ners. Mayo Clin Proc 74:955, 1999

8. Wright J, Johns R, Watt I, et al: Health effects of obstructivesleep apnea and the effectiveness of continuous positive air-way pressure: A systematic review of the research evidence. BrMed J 314:851, 1997

9. Peppard PE, Young T, Palta M, et al: Prospective study of theassociation between sleep-disordered breathing and hyperten-sion. N Engl J Med 342:1378, 2000

0. Peker Y, Hedner J, Norum J, et al: Increased incidence of cardio-vascular disease in middle-aged men with obstructive sleep apnea:A 7-year follow-up. Am J Respir Crit Care Med 166:159, 2002

1. Douglas NJ, Thomas S, Jan MA: Clinical value of polysomnog-raphy. Lancet 339:347, 1992

2. Flemons WW: Measuring quality of life in patients with sleepapnea: Whose life is it anyway? Thorax 59:457, 2004

3. Weaver EM, Woodson BT, Steward DL: Polysomnography indexesare discordant with quality of life, symptoms, and reaction timesin sleep apnea patients. Otolaryngol Head Neck Surg 132:255,2005

4. Weaver EM, Kapur V, Yueh B: Polysomnography vs self-re-ported measures in patients with sleep apnea. Arch Otolaryn-gol Head Neck Surg 130:453, 2004

5. Schipper H, Clinch JJ, Olweny CLM: Quality of life studies:Definitions and conceptual issues, in Spilker B (ed): Quality ofLife and Pharmacoeconomics in Clinical Trials (ed 2). Philadel-phia, PA, Lippincott-Raven, 1996, pp 11-23

6. Moyera CA, Sonnada SS, Garetzc SL, et al: Quality of life inobstructive sleep apnea: A systematic review of the literature.Sleep Med 2:477, 2001

7. Woodson BT, Steward DL, Weaver EM, et al: A randomized trialof temperature-controlled radiofrequency, continuous positiveairway pressure, and placebo for obstructive sleep apnea syn-drome. Otolaryngol Head Neck Surg 128:848, 2003

8. Weaver TE, Laizner A, Evans LK, et al: An instrument to mea-sure functional status outcomes for disorders of excessivesleepiness. Sleep 20:835, 1997

9. Walker-Engstrom ML, Wilhelmsson B, Tegelberg A, et al: Qual-ity of life assessment of treatment with dental appliance orUPPP in patients with mild to moderate obstructive sleepapnea: A prospective randomized 1-year follow-up study.J Sleep Res 9:303, 2000

0. Kuo PC, West RA, Bloomquist DS, et al: The effect of mandib-ular osteotomy in three patients with hypersomnia sleep ap-nea. Oral Surg Oral Med Oral Path 48:385, 1979

1. Riley RW, Powell NB, Li KK, et al: Surgery obstructive sleepapnea: Long-term clinical outcomes. Otolaryngol Head NeckSurg 112:415, 2000

2. Li KK, Guilleminault C, Riley RW, et al: Obstructive sleepapnea and maxillomandibular advancement: An assessment ofairway changes using radiographic and nasopharyngoscopicexaminations. J Oral Maxillofac Surg 60:526, 2002

3. Fairburn SC, Waite PD, Vilos G, et al: Three-dimensionalchanges in upper airways of patients with obstructive sleepapnea following maxillomandibular advancement. J Oral Max-illofac Surg 65:6, 2007

4. Li KK, Powell NB, Riley RW, et al: Long term results of maxil-lomandibular advancement surgery. Sleep Breath 4:137, 2000

5. Prinsell JR: Maxillomandibular advancement surgery in a sitespecific treatment approach for obstructive sleep apnea in 50consecutive patients. Chest 116:1519, 1999

6. Hochban W, Conrad R, Bradenburg U, et al: Surgical maxillo-facial treatment of obstructive sleep apnea. Plast Reconstr Surg99:619, 1997

7. Montserrat JM, Ferrer M, Hernandez L, et al: Effectiveness ofCPAP treatment in daytime function in sleep apnea syndrome:A randomized controlled study with an optimized placebo.Am J Respir Crit Care Med 164:608, 2001

8. Monasterio C, Vidal S, Duran J, et al: Effectiveness of continu-ous positive airway pressure in mild sleep apnea–hypopneasyndrome. Am J Respir Crit Care Med 164:939, 2001

9. Faccenda JF, Mackay TW, Boon NA, et al: Randomized placebo-controlled trial of continuous positive airway pressure onblood pressure in the sleep apnea–hypopnea syndrome. Am JRespir Crit Care Med 163:344, 2001

0. Izci B, Firat H, Ardic S, et al: Adaptation of functional outcomesof sleep questionnaire (FOSQ) to Turkish population. TuberkToraks 52:224, 2004

1. Nieto FJ, Young TB, Lind BK, et al: Association of sleep disor-dered breathing, sleep apnea, and hypertension in a largecommunity-based study. JAMA 283:1829, 2000

2. Peppard PE, Young T, Palata M, et al: Prospective study of theassociation between sleep-disordered breathing and hyperten-sion. N Engl J Med 342:1378, 2000

3. Bixler EO, Vgontzas AN, Lin HM, et al: Association of hyperten-

sion and sleep-disordered breathing. Arch Intern Med 160:2289,2000