Scientific investigations

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1 Sientifi investigtions Depression nd Sleep-Relted Symptoms in n Adult, Indigenous, North Amerin Popultion Colleen L. Froese, M.D. 1,2 ; Arsln Butt, M.S. 2,3 ; Aln Mulgrew, M.D. 2,3 ; Rupi Cheem, R.N. 2 ; Mry-Ann Speirs, B.B.A. 2 ; Crmen Gosnell 2 ; Jon Fleming, M.D. 1,2 ; John Fleethm, M.D. 2,3 ; C Frnk Ryn, M.D. 2,3 ; Nji T. Ays, M.D., M.P.H Deprtment of Psyhitry, University British Columi, Vnouver, BC; 2 Sleep Disorders Progrm, University of British Columi Hospitl, Vnouver, BC; 3 Deprtment of Mediine, University of British Columi, Vnouver, BC; 4 Centre Clinil Epidemiology nd Evlution, Vnouver Costl Helth Reserh Institute, Vnouver, BC Study Ojetives: Symptoms relted to sleep disorders re ommon nd my hve sustntil dverse impts on mentl helth. Indigenous North Amerins (Amerin Indin) re medilly vulnerle popultion with redued ess to helthre servies. The purposes of this study were to ssess (1) the prevlene of sleep symptoms nd (2) the reltionships etween symptoms nd depression in this popultion. Methods: We performed ommunity-sed, door-to-door, rosssetionl survey of 3 indigenous North Amerin groups (Gitxsn, Nisg nd Tsimshin) living in the northwestern prt of British Columi. Between My nd Septemer of 2006, sujets ompleted omprehensive questionnire tht inluded questions out sleep hits, medil history, sujetive sleepiness (Epworth Sleepiness Sle), nd depression (Personl Helth Questionnire [PHQ-9]). Weights nd heights were lso mesured. Results: Four hundred thirty dults prtiipted in the study (response rte = 42%). Their men ge ws 43.2 yers. Three hundred ninetythree greed to hve heights nd weights mesured. Their men ody mss index (BMI) ws 31.0 ± 9.2 kg/m 2 ; 45% of them (177/393) were oese (BMI > 30 kg/m 2 ), nd 11% (43/393) were moridly oese (BMI > 40 kg/m²). The prevlene of sleep omplints ws high; insomni symptoms ws reported y 17.2%, symptoms of restless legs syndrome (RLS) y 17.7%, nd frequent witnessed pnes reported (i.e., eing told they stopped rething t lest 3 nights per week) y 7.6%. Of the 76 ptients who hd RLS symptoms, only 3 (3.9%) reported hving reeived dignosis of RLS from physiin. Thirty-three sujets Sleep disorders re extremely ommon nd hve sustntil dverse impts on oth qulity of life nd mentl helth. Three of the most ommon sleep disorders re insomni, ostrutive sleep pne (OSA), nd restless legs syndrome (RLS). Dislosure Sttement This ws not n industry supported study. The uthors hve indited no finnil onflits of interest. Sumitted for pulition Ferury, 2008 Aepted for pulition My, 2008 Address orrespondene to: Nji T. Ays, Assoite Professor of Mediine, 7th Floor, G & L Dimond Helth Cre Centre, 2775 Lurel Street, Vnouver, BC V5Z 1M9; Tel: (604) ; E-mil: nji.ys@vh. reported hving frequent witnessed pnes, ut only 5 of them (15.1%) reported hving reeived dignosis of OSA from physiin. The men PHQ9 sore ws 4.86 ± 5.13 (reported y 389 sujets). Twenty-eight sujets (7.20%) hd moderte to severe depression, with PHQ-9 sore of 15 or greter. In multivrile liner regression nlysis, insomni symptoms, witnessed pnes, nd RLS symptoms were independently ssoited with n inrese in PHQ9 sore; frequent witnessed pnes were ssoited with n inrese in PHQ9 y 2.46 (95% onfidene intervl: ), insomni symptoms y 4.49 (95% onfidene intervl: ), nd RLS symptoms y 1.82, (95% onfidene intervl: ). Conlusions: Sleep symptoms nd depression re ommon in the indigenous North Amerin popultion of northern British Columi. Sleep-relted symptoms (insomni symptoms, witnessed noturnl pnes, nd RLS symptoms) re independently ssoited with depression sores. Improving ess to sleep-relted dignosti nd therpeuti servies my sustntilly improve mentl helth in this vulnerle ptient popultion. Keywords: Sleep, epidemiology, originl, depression, restless legs syndrome, sleep pne, insomni, Amerin Indin Cittion: Froese CL; Butt A; Mulgrew A; Cheem R; Speirs MA; Gosnell C; Fleming J; Fleethm J; Ryn F; Ays NT. Depression nd sleep-relted symptoms in n dult, indigenous, north merin popultion. J Clin Sleep Med 2008;4(4): Psyhitri disorders suh s depression nd nxiety re more ommon in people who hve insomni. Furthermore, hroni insomni is lso risk ftor for the development of psyhitri disorders. 1 OSA is ommon respirtory sleep disorder hrterized y reurrent upper irwy ollpse during sleep, leding to reurrent sphyxi nd sleep frgmenttion. Ptients with OSA re t inresed risk of hving motor vehile rshes, rdiovsulr disese, hypertension, nd stroke. 2,3 Furthermore, OSA is n independent risk ftor for the development of inident depression. 4 Tretment of OSA leds to sustntil improvements in dytime sleepiness, mood, nd qulity of life. 5,6 RLS is sensorimotor disorder tht hs signifint impt on sleep. Chrteristi symptoms inlude the desire to move the lims ssoited with presthesi or dysesthesi, whih egin or worsen during periods of intivity predomintely in the Journl of Clinil Sleep Mediine, Vol. 4, No. 4,

2 Depression nd Sleep evening nd re relieved y movement. 7 A numer of studies hve demonstrted signifint ssoitions etween RLS nd dytime dysfuntion, depression, nd nxiety Indigenous North Amerin people (Amerin Indin) re medilly vulnerle popultion with redued ess to helthre servies. They hve n inresed risk of developing helth prolems, suh s dietes, rdiovsulr disese, oesity, nd trumti injuries Furthermore, this popultion hs high rtes of depression nd other mentl helth prolems. 14 The purpose of this study ws to ssess the prevlene of ommon sleep symptoms in this popultion nd to determine whether these symptoms re ssoited with depression. To omplish this, we performed ommunity-sed survey study of dult indigenous North Amerin people living in the northwestern prt of British Columi, Cnd. Desription of Communities Methods Between My 2006 nd Septemer 2006, 2 indigenous North Amerin reserh ssistnts fmilir with the lol ommunities ttempted to ontt nd memers in northwestern British Columi. These inluded 3 groups (Gitxsn, Nisg nd Tsimshin) loted in geogrphi re of pproximtely 150 sq km. The ssistnt working in the Nisg re of New Aiynsh (totl registered popultion 677) hd ess to list of phone numers of nd memers nd ws le to mke initil ontt y phone to explin the purpose of the study nd set up meeting time. The other ssistnt, who did not hve ontt list of nd memers, ompleted door-to-door survey of the following Gitxsn villges (popultions re listed in prentheses): Gitnmx (732), Kispiox (668), Gitwngok or Kitwng (453), Kitwnool or Gitnyow (344), Hgwilget (209), nd Gitsegukl (477) nd the Tsimshin villge of Kitsumklum (187). Tehniques The sujets ompleted omprehensive questionnire tht inluded questions out sleep nd helth hits, sleep symptoms, medil history, nd geneti kground. Prtiipnts lso ompleted n Epworth Sleepiness Sle (ESS) 15 nd the Personl Helth Questionnire (PHQ-9). 16 The ESS is vlidted questionnire to ssess sujetive sleepiness; sujets re sked out their tendeny to fll sleep over the lst month under 8 different senrios. The sore rnges from 0 (no sleepiness) to 24 (sustntil dytime sleepiness), with sore greter thn 10 usully onsidered to e norml. The PHQ-9 is 9-item vlidted questionnire to determine the severity of depression. The sore rnges from 0 to 27 (higher sore indites more severe depressive symptoms), with sore of 15 or greter inditing t lest moderte depression. All sujets were sked the following question: How often do you hve diffiulty flling sleep, hve frequent wkenings during the night, wke too erly nd re unle to get k to sleep, or wke feeling unrefreshed? Sujets were sked to indite whether they reported these never, rrely, few nights month, few nights week, or every night or lmost every night. Sujets who responded every night or lmost every night to this question were onsidered to hve insomni symptoms. Questions relted to symptoms of OSA inluded questions out the frequeny of loud snoring nd witnessed pnes. Four questions relted to the Interntionl RLS Study Group s dignosti riteri for RLS inluded (1) Do you hve norml senstions in your rms or legs, i.e., pins or needles, nts rwling, nd desire to move your lims? ; (2) Do you hve n urge to move or unplesnt senstions in the lims tht egin or worsen when you rest lying down or sitting? ; (3) Do you hve n urge to move or unplesnt senstions in the lims tht re prtilly or totlly relieved y movement, suh s wlking or strething? ; nd (4) Do you hve n urge to move or unplesnt senstions in the lims tht re worse during the evening or night? For our nlysis, ptients who reported ll of these symptoms were onsidered to hve RLS symptoms. 7 Sujets who greed hd their height, weight, nd nek irumferenes mesured. All prtiipnts were given ooklet entitled, Help Yourself to Good Night s Sleep, for their prtiiption in the study; otherwise, there ws no other inentive to prtiipte in the study. The Nisg Vlley Helth Authority, the Wilxo oskwhl Nisg Bord, the Chief Counilor of the Kitsumklum Bnd offie, nd the Behviourl Reserh Ethis Bord of The University of British Columi pproved this study. Informed onsent ws otined from ll prtiipnts. Dt Anlysis There were 5 mjor outomes of interest: insomni symptoms, frequent witnessed pnes, RLS symptoms, ESS, nd depression sore. For ll outomes, we tested numer of vriles in univrite nlyses (liner of logisti regression depending on whether the outome vrile ws ontinuous or dihotomous) to ssess whether eh vrile ws ssoited with the outome of interest. These vriles inluded ge, sex, BMI, nek irumferene, use of lohol (totl numer of ottles/ns of eer, glsses of wine, or shots of liquor) in 11 tegories, rnging from never or less thn one per month to more thn 20 per dy, nd urrent igrette smoking (6 tegories from none to 45 or more per dy). For eh outome, we lso seleted numer of dditionl vriles for testing tht were sed upon the judgment of the investigtors. Speifilly, for insomni symptoms, we lso tested ssoitions with frequent snoring, ESS sore, use of ntidepressnt meditions ( frequently or lmost lwys, ) nd depression sore. For RLS symptoms, we lso tested frequent snoring, use of ntidepressnt meditions, nd presene of dotor-dignosed nemi. For frequent witnessed pnes, we lso tested depression sore, presene of RLS, nd ESS sore. For ESS sore, we tested depression sore, snoring, self-reported nemi, RLS symptoms, presried sleeping meditions, nonpresription sleeping meditions, use of herl or helth food trditionl sleeping ids, ntidepressnt use, nd short sleep ( 6 hours of sleep on weekdys). For depression sore, we lso tested witnessed pnes, insomni symptoms, RLS symptoms, nd ntidepressnt medition use. Multivrite modelling ws used susequently s required; ge nd sex were used in ll models, nd other vriles were dded if the p vlue ws less thn 0.10 in univrite nlyses. Journl of Clinil Sleep Mediine, Vol. 4, No. 4,

3 CL Froese, A Butt, A Mulgrew et l Tle 1 Demogrphis of the Study Popultion Demogrphi Results Age, y 43.2 ± 14.3 BMI, kg/m ± 9.2 Nek irumferene, m 39.4 ± 7.6 Men 185 (44) Current smoking 170 (39.5) Alohol use 25 (5.8) Use of ntidepressnt medition d 20 (4.7) Use of presription sleep meditions d 10 (2.3) Use of herl, helth food, trditionl sleep remedies d 3 (0.70) Self-reported dietes 24 (5.6) Self-reported hypertension 58 (13.5) Self-reported hert ttk 2 (0.47) Dt re provided s men ± SD or numer (perentge). Dt ville from 393 sujets. Dt ville in 374 sujets The totl numer of ottles or ns of eer, glsses of wine, or shots of liquor is 6 or more per dy. d The response to use of medition is frequently or lmost lwys. Sttistil nlyses were performed with SAS 9.1. A p vlue of 0.05 ws onsidered to e sttistilly signifint. All dt re reported s men ± SD unless otherwise noted. Response Rte Results Four hundred nd thirty dults (ge 18 yers) ompleted the surveys. The totl registered popultion of the reserves surveyed ws The portion of dults 18 yers of ge nd older is estimted to e 73.6%, nd pproximtely 37% of Aoriginl people in British Columi who re registered to the reserve live on the reserve (2001 Census Cnd). 17 Our popultion estimte ws therefore = 1020, with onsequent response rte of 430 out of 1020 or 42%. Of note, pproximtely 80% of sujets who were ontted greed to prtiipte. Demogrphis The men ge ws 43.2 yers ± 14.3 yers, 185 of them (44%) were men, nd 233 (56%) were women. Three hundred ninety-three sujets greed to hve their weight nd height mesured. Their demogrphis re shown in Tle 1. Prevlene of Sleep Symptoms Insomni Symptoms The prevlene of insomni symptoms ws 17.2%. Signifint univrite nd multivrite ssoitions re shown in Tle 2. Depression sore, igrette smoking, nd use of ntidepressnt meditions were signifintly ssoited with the presene of insomni symptoms; however, ge, BMI, nd sex were not (p > 0.3). The ESS sore ws not signifintly ssoited with insomni symptoms, though there ws trend (p = 0.06). Tle 2 Ftors Assoited with Insomni Symptoms Risk Ftors OR (95% CI) p Vlue Univrite OR Depression Sore 1.20 ( ) < Antidepressnts 2.67 ( ) 0.04 ESS 1.07 ( ) d 0.06 Alohol Intke 1.10 ( ) 0.09 Numer of igrettes 1.40 ( ) Adjusted OR Depression Sore 1.24 ( < Use of ntidepressnt medition frequently or lmost lwys. Adjusted for ge, sex, depression sore, Epworth Sleepiness Sle (ESS) sore, lohol intke (11-point ordinl sle), numer of igrettes (6-point ordinl sle), nd ntidepressnt meditions. For eh 1-point inrese in Personl Helth Questionnire (PHQ)-9. d For eh 1-point inrese in ESS. OR refers to odds rtio; CI, onfidene intervl. In the multivrite model, only depression sore remined signifintly ssoited with insomni symptoms. RLS Sy m p t o m s The prevlene of RLS symptoms ws 17.7% (76/430). Signifint univrite preditors re shown in Tle 3. Use of ntidepressnt meditions frequently or lmost lwys, BMI, nd snoring were not signifint preditors (p > 0.18). In multivrite logisti regression nlyses, only ESS sore nd depression sore remined signifintly ssoited with RLS (though femle sex trended to signifine with p = 0.07). OSA Sy m p t o m s Frequent snoring (defined s snoring t lest 3 nights per week) ws reported y 36% (154/430) of sujets. The only 2 vriles signifintly ssoited with snoring were BMI (p = 0.007) nd ESS sore (p < 0.001), though there ws trend for mle sex to e ssoited with snoring (p = 0.06). Nek irumferene nd ge were not. Thirty-three of 430 sujets (7.6%) reported eing told tht they stopped rething t lest 3 nights per week. Signifint ssoitions (Tle 4) with witnessed pnes inluded BMI, mle sex, depression sore, nd frequent snoring. Nek irumferene (p = 0.11), ESS sore (p = 0.23), nd ge were not (p = 0.54). In the multivrite model, sex, BMI, nd depression sore remined independent preditors of frequent witnessed pnes. Sujetive Dytime Sleepiness The men ESS sore ws 4.45 ± 7.6 (reported y 350 sujets), nd 22 sujets (6.3%) hd n ESS sore of greter thn 10. Signifint independent preditors of ESS sore (multiple liner regression) re shown in Tle 5. Depression The men PHQ-9 sore ws 4.86 ± 5.13 (reported y 389 sujets). One hundred seventy-one sujets (44%) hd t lest Journl of Clinil Sleep Mediine, Vol. 4, No. 4,

4 Tle 3 Ftors Assoited with RLS Risk Ftors OR (95% CI) p Vlue Univrite OR Depression sore 1.10 ( ) < ESS sore 1.21 ( ) < Femle sex 2.27 ( ) Self-reported nemi 4.98 ( ) Age 0.98 ( ) 0.01 Adjusted OR d ESS sore 1.17 ( ) Depression sore 1.07 ( ) Femle sex 1.80 ( ) 0.07 For eh 1-point inrese in Personl Helth Questionnire (PHQ)-9 sore. For eh 1-point inrese in Epworth Sleepiness Sle (ESS) sore. For eh yer of ge. d Adjusted for sex, ge, nemi, depression sore, ESS, nd use of ntidepressnt meditions OR refers to odds rtio; CI, onfidene intervl. We did not identify onsistent effet of sex or ge on insomni omplints in our study. The resons for this re unler ut re open to speultion. Perhps ulturl, soioeonomi, or ethni ftors hve modified the reltionship etween insomni symptoms nd ge or sex in our popultion. Nevertheless, our findings re onsistent with those of other studies in indigenous popultions (i.e., Mori in New Zelnd) tht hve shown inonsistent effets of sex on insomni symptoms. 18 Symptoms of insomni, RLS, nd depression hve een intritely linked, nd there is ongoing speultion regrding the reltionship etween these onditions. A review y Gri-Borreguero indites tht the prevlene of RLS vries etween 2.5% nd 10% in generl-popultion studies when the Interntionl RLS Study Group dignosti riteri were used. 19 Higher prevlene rtes hve een ssoited with poor overll helth, poor mentl helth, smoking, high BMI, inresing ge, nd nemi. 8 A omintion of these ftors most likely explins the high prevlene of RLS symptoms in our indigenous North Amerin popultion. Ethni nd geneti ftors ply importnt roles in the risk of OSA. 20,21 These differenes my e relted to vritions in rniofil struture, oesity, ody ft distriution, nd soioeonomi sttus. In generl, nek irumferene is mjor risk ftor for OSA, s this likely represents mrker of ft deposition in the upper irwy. However, in Polynesin men, s ompred with Cusins, ephlometri mesures re more preditive of sleep pne thn is nek irumferene, suggesting tht different ftors my e more importnt ftors in different popultions. 22 In our study, we lso did not find signifint ssoition etween nek irumferene nd OSA symptoms (snoring or witnessed pnes), suggesting tht fetures ontriuting to OSA in indigenous North Amerin people my e different from those in Cusins. Future studies tht inlude detiled irwy exmintions, ephlometry, nd polysomnogrphy might help us understnd the ontriuting ftors for OSA in this popultion. Our results lso extend those from the Sleep Hert Helth Study, 23,24 ohort tht inludes sujets from vriety of ethni groups, inluding sustntil numer of Amerin Indins. In the Sleep Hert Helth Study, symptoms of sleep pne (witnessed pnes, loud snoring) were frequently reported y Amerin Indins. Furthermore, Amerin Indin women (ut not men) hd more sleep pne-relted symptoms thn did nonmild depression, with PHQ-9 sore of 5 or higher; 7.20% (28 sujets) hd moderte to severe depression, with PHQ-9 sore of 15 or higher; nd 1.54% hd severe depression, with PHQ-9 sore of 20 or higher. Signifint independent preditors of PHQ-9 sore re shown in Tle 6 (multiple liner regression). All 3 sleep omplints (RLS, insomni symptoms, nd witnessed pnes) were signifintly ssoited with PHQ-9 sores. Motor Vehile Crshes As seondry nlysis, we exmined ssoitions with self-reported motor vehile rsh (MVC). Twenty-five (5.81%) sujets reported eing involved in t lest 1 MVC in the previous yer. Signifint univrite ssoitions with MVC inluded depression sore (p = 0.03), ESS sore (p = 0.03), nd use of stimulnt meditions (p = 0.04). Age, lohol use, nd sex were not signifint preditors of MVC. In multivrite logisti regression nlyses (inluding ESS, ge, sex), only ESS remined signifint preditor (odds rtio = 1.12 for eh 1-point inrese in ESS sore, 95% onfidene intervl: , p = 0.04). Physiin Dignosis of Sleep Disorders Seventy-six ptients hd RLS sed on questionnire, ut only 3 (3.9%) reported hving physiin dignosis of RLS. Thirtythree sujets reported frequent witnessed pnes, ut only 5 of them (15.1%) reported physiin dignosis of OSA. Disussion In our study, sleep-relted symptoms were ommon; 17.2% of the sujets reported insomni symptoms, 17.7% reported RLS symptoms, nd 7.6% reported frequent witnessed pnes. Oesity (45%) nd depression (44%) were lso ommon in this popultion. Furthermore, in this ross-setionl study, insomni symptoms, RLS symptoms, nd frequent witnessed pnes were independently ssoited with depression sores. Depression nd Sleep Tle 4 Ftors Assoited with Frequent Witnessed Apnes Risk Ftors OR (95% CI) p Vlue Univrite OR BMI 1.03 ( ) 0.04 Femle sex 0.38 ( ) 0.01 Depression sore 1.11 ( ) Adjusted OR Femle sex 0.13 ( ) BMI 1.07 ( ) Depression sore 1.13 ( For eh 1-kg/m 2 inrese in ody mss index (BMI). For eh 1-point inrese in Personl Helth Questionnire (PHQ)-9. Adjusted for sex, ge, Epworth Sleepiness Sle (ESS) sore, BMI, nd depression sore. Frequent witnessed pnes our 3 nights per week). OR refers to odds rtio; CI, onfidene intervl. Journl of Clinil Sleep Mediine, Vol. 4, No. 4,

5 CL Froese, A Butt, A Mulgrew et l Tle 5 Ftors Independently Assoited with Epworth Sleepiness Sle Sore Risk Ftors Prmeter Estimte p Vlue (95% CI) Depression sore 0.19 ( ) Frequent snoring 1.64 ( ) RLS symptoms 2.03 ( ) Herl or helth food or trditionl sleeping id 0.92 ( ) 0.04 Short sleep ( ) Adjusted for depression sore, snoring, self-reported nemi, restless legs syndrome (RLS) symptoms, presried sleeping meditions, nonpresription sleeping meditions, herl or helth food trditionl sleeping ids (6-point sle), frequent ntidepressnt use, short sleep ( 6 hours of sleep on week dys), ge, nd sex. CI refers to onfidene intervl. Hispni white women. Amerin Indins lso hd lighter sleep (more Stge 1) thn did other Ethni groups. In mil survey of lrge rndom smple of the popultion in New Zelnd, 25 Mori hd higher men ESS sore (7.5) ompred with non-mori (6.0). This sore ws muh higher thn the men ESS sore of 4.4 in our study. There re numer of potentil explntions for this differene, inluding diffiulty understnding the questions, relutne to omplin out sleepiness, ulturl eptne of dytime sleepiness, or less dytime sleepiness. Furthermore our study ws onduted etween My nd Septemer, 26 nd our results my hve een different in the winter when our study popultion reeives, on verge, only 6 hours of sunlight per dy, s opposed to 18 hours per dy in the summer. The ESS sore ws n independent risk ftor for reporting reent MVC nd is onsistent with the results of previous studies tht hve shown tht sujetive sleepiness is risk ftor for eing involved in n MVC. 27 Snoring nd RLS were oth ssoited with inresed ESS in our study, suggesting tht treting RLS nd OSA my improve dytime sleepiness nd potentilly redue the rtes of MVC in this popultion. Depression ws very ommon in our popultion, with 44% of sujets reporting t lest mild disese. All 3 sleep symptoms (insomni symptoms, frequent witnessed pnes, RLS) were independently ssoited with PHQ-9 sore. This effet persisted even fter ontrolling for sleep symptoms y removing this item from the PHQ-9 sore for nlysis. These findings re onsistent with those from other studies tht hve demonstrted reltionships etween depression nd sleep symptoms in the non Amerin Indin popultion. 28 For exmple, in popultion-sed longitudinl study, Pepprd nd ssoites showed tht sujets with moderte to severe OSA were signifintly more likely to develop depression (odds rtio = 2.6). 5 Given tht ours is ross-setionl study, we re unle to determine whether depression uses the sleep symptoms or vie vers. Nevertheless, we onsider it likely tht untreted OSA, insomni, nd RLS ffet sleep qulity nd quntity nd exerte depression in indigenous North Amerin people. Despite the reltively high prevlene of sleep symptoms, rtes of physiin dignosis of sleep disorders were low. In ptients with symptoms of RLS, only 3.9% were dignosed with the disorder y physiin. Similrly, only 15% of ptients Tle 6 Ftors Independently Assoited with PHQ-9 Sores: Multivrite Liner Regression Model Risk Ftors Inrese in PHQ-9 Sore p Vlue (95% CI) Frequent witnessed pnes 2.46 ( ) Insomni symptoms 4.49 ( ) < RLS symptoms 1.82 ( ) Femle sex 1.74 ( ) < Antidepressnt medition 5.79 ( ) < BMI ( ) 0.04 Alohol Intke 0.28 ( ) 0.03 Model inluded witnessed pnes, ge, sex, insomni symptoms, restless legs syndrome (RLS) symptoms, ntidepressnt medition use, ody mss index (BMI), numer of igrettes smoked (6-point ordinl sle), nd lohol intke (11-point ordinl sle). Age (p = 0.09) nd smoking (p = 0.59) were not signifintly ssoited with Personl Helth Questionnire (PHQ-9) in the multivrite model. CI refers to onfidene intervl. For eh 1-kg/m 2 inrese in BMI. with frequent witnessed pnes reported hving physiinsed dignosis of OSA. Witnessed pnes re speifi rther thn sensitive mrker of OSA, in tht mny ptients with OSA do not report witnessed pnes, ut mny who report witnessed pnes do hve OSA. We would therefore speulte tht the overll proportion of ll indigenous North Amerins with OSA whose symptoms re dignosed would likely e muh less thn 15% (i.e., proportion of individuls with frequent witnessed pnes reported to hve dignosed OSA in our smple) nd sustntilly lower thn the proportion of dignosed OSA in non Amerin Indin popultions. 29 This low rte of dignosis proly reflets the poor ess this popultion hs to sleep-disorder dignosti nd therpeuti servies. For exmple, polysomnogrphy is only ville in mjor urn enters, whih, for our study popultion, requires either 2-hour flight or 2-dy drive. This is lerly n importnt issue given tht untreted OSA is ssoited with n inresed risk of depression, rdiovsulr disese, nd MVC. Our study hd numer of strengths. First, this ws ommunity-sed study, rther thn study sed on ptients referred to sleep disorder enter for suspeted sleep disorder. Seond, we performed diret mesurements of weights, heights, nd nek irumferene rther thn relying on self-reported mesures, whih n e inurte. We knowledge tht our study lso hd numer of limittions. First, we surveyed memers of only smll re of northern British Columi. As suh, our results my not e representtive of individuls outside this re or t different ltitudes. Seond, mny of our outomes (e.g., MVCs) were sed upon self-reports s opposed to vlidted mesures (suh s insurne reords). Third, we did not perform ny form of sleep monitoring, so our nlysis ws sed on self-reported symptoms. Sine witnessed pnes re n insensitive symptom of OSA, the proportion of sujets with OSA in our popultion my e muh greter thn 7.6%. Fourth, the study ws performed in the summertime, nd different results my hve een otined in the wintertime. The prevlene of depression my e higher in the wintertime euse of sesonl ffetive disorder. Fifth, lthough our response rte ws resonle, mny potentil sujets did not prtiipte in the Journl of Clinil Sleep Mediine, Vol. 4, No. 4,

6 study. We ttempted to inlude everyone living in these ommunities in our study; sujets were generlly not inluded euse they were not ville or did not gree to prtiipte. Sujets who prtiipted my hve thus een different from those who did not, potentilly ising the study. Sixth, the questions we used hve not een vlidted in this popultion. The ility of self-reported symptoms to predit the presene of sleep disorders (e.g., OSA or RLS) is not known. Indeed, 1 study hs shown tht OSA-relted symptoms my hve lower preditive vlue for polysomnogrphilly determined OSA in Amerin Indins, lthough, even in this study, these symptoms were still signifintly orrelted with the presene of OSA. 24 Conlusion Sleep symptoms nd depression re ommon in the indigenous North Amerin people in northern British Columi. Sleep-relted symptoms (insomni symptoms, witnessed noturnl pnes, nd RLS symptoms) re independently ssoited with depression sores. Improving ess to sleep-disorder dignosti nd therpeuti servies my sustntilly improve mentl helth in this vulnerle ptient popultion. Aknowledgments This work ws supported y Mihel Smith Foundtion for Helth Reserh (MSFHR) Infrstruture Grnt (Sleep-disordered Brething). Dr. Ays ws supported y CIHR/BCLA New Investigtor Awrd, nd MSFHR Sholr Awrd Referenes Nekelmnn D, Mykletun A, Dhl AA. Chroni insomni s risk ftor for developing nxiety nd depression. Sleep 2007;30: Yggi H, Conto J, Kernn WN, et l. Ostrutive sleep pne s risk for stroke nd deth. N Engl J Med 2005;353: Young T, Pepprd PE, Gottlie DJ. Epidemiology of ostrutive sleep pne: popultion helth perspetive. Am J Respir Crit Cre Med 2002;165: Pepprd PE, Szklo-Coxe M, Hl KM, Young T. Longitudinl ssoition of sleep-disordered rething disorder nd depression. Arh Intern Med 2006;166: Klonoff H, Fleethm JA, Tylor RD, Clrk C. Tretment of ostrutive sleep pne. Physiologil nd psyhologil onomitnts. J Nerv Ment Dis 1987;175: Mlhotr A, Ays N, Epstein L. 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