- Email: [email protected]
Population-based study of facial morphology and excessive daytime somnolence
Pathophysiology 21 (2014) 289–292
Population-based study of facial morphology and excessive daytime somnolence Pablo R. Castillo a,1 , Robertino M. Mera b , Mauricio Zambrano c , Oscar H. Del Brutto d,∗,1 a
Sleep Disorders Center, Mayo Clinic College of Medicine, Jacksonville, FL, United States b Gastroenterology Department, Vanderbilt University, Nashville, TN, United States c Community Center, Atahualpa, Ecuador d School of Medicine, Universidad Espíritu Santo – Ecuador, Guayaquil, Ecuador Received 14 May 2014; received in revised form 23 May 2014; accepted 6 June 2014
Abstract Studies in patients seeking attention for nasal obstruction or pharyngeal disorders suggest that craniofacial abnormalities correlate with obstructive sleep apnea, but there is little information on the relevance of this association in the population at large. We aimed to determine whether characteristics of facial morphology correlate with excessive daytime somnolence (EDS) in a population-based, door-to-door survey. Residents of a village in rural Ecuador were screened with the Epworth sleepiness scale to assess EDS and underwent physical examination with attention to nasal septum deflection, mandibular retrognathia and presence of Friedman’s palate position type IV. From 665 participants aged ≥40 years, 155 had EDS, 98 had nasal septum deflection, 47 had mandibular retrognathia and 528 had a Friedman’s palate position type IV. In a logistic regression model adjusted for age, sex, body mass index, and nightly sleep hours, persons with nasal septum deflection were twice as likely to have EDS (p = 0.009). The other two variables were not associated with EDS. Identification of nasal septum deflection may be a cost-effective method of detecting persons at risk for obstructive sleep apnea in remote areas where sophisticated technology is not readily available. © 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Obstructive sleep apnea; Daytime somnolence; Nasal septum deflection; Nasal septum deviation; Ecuador
1. Introduction Obstructive sleep apnea (OSA) is a common medical condition that decreases quality of life and increases cardiovascular risk, stroke incidence, and all-cause mortality [1]. Conservative figures suggest that 10% of adults worldwide have OSA, but this condition remains undetected in rural areas of developing countries, where technology needed for its definitive diagnosis is not readily available. To reduce the increasing burden of cardiovascular diseases in rural areas of low- and middle-income countries, ∗ Corresponding author at: Air Center 3542, PO Box 522970, Miami, FL 33152-2970, United States. Tel.: +1 59342285790. E-mail address: [email protected] (O.H. Del Brutto). 1 These authors contributed equally to this work.
http://dx.doi.org/10.1016/j.pathophys.2014.06.001 0928-4680/© 2014 Elsevier Ireland Ltd. All rights reserved.
implementation of cost-effective strategies such as recognition of modifiable risk factors – including OSA – is mandatory [2]. In these regions, mass screening with field instruments designed to detect persons with probably OSA may be complicated by cross-cultural factors and illiteracy. There is a need for reliable screening tools to facilitate early detection of persons with risk of OSA in underserved populations. Although the relationship between abnormal craniofacial characteristics and OSA has been documented in patients seeking attention for sleep-disordered breathing or a specific nasal or pharyngeal disorder [3–5], little is known about the relevance of this association in the population at large, particularly in underserved populations. We report the findings of a population-based study in rural Ecuador, designed to evaluate characteristics of facial morphology and to determine whether they can identify
290
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292
Fig. 1. Study subjects with nasal septum deflection (left), mandibular retrognathia (center), and Friedman palate position type IV (right).
persons at risk of OSA who should be referred for further evaluation. 2. Methods The IRB of Hospital-Clínica Kennedy, Guayaquil, Ecuador (FWA00006867), approved the protocol and informed consent forms. Atahualpa is located in coastal Ecuador, and is representative of the rural villages of the region. More than 95% of the population belongs to the Ecuadorian Native/Mestizo ethnic group (Amerindians). Phenotypically, these persons are of short stature and most have abdominal obesity. The Atahualpa Project is a population-based cohort study that evaluates the relationships between sleep disorders and cardiovascular risk factors in rural Ecuador. Methodology has been detailed elsewhere [6]. For this part of the study, trained field personnel conducted a door-to-door survey to identify all Atahualpa residents aged ≥40 years. Consenting persons underwent a physical examination with attention to the height, weight, and characteristics of facial morphology that have been associated with an increased risk of OSA, including nasal septum deflection, mandibular retrognathia, and a Friedman’s palate position type IV. We also assessed the number of nightly sleep hours and the presence of excessive daytime somnolence (EDS) (used as a proxy for OSA) by the use of the Epworth sleepiness scale [7]. Nasal septum deflection was characterized as significant when it was deviated ≥5 mm away from the midline causing external nasal deformity and associated with subjective report of nasal flow. Mandibular retrognathia was categorized as present when the anterior prominence of the chin was ≥2 mm behind a virtual line drawn from the vermillion border of the lower lip to the chin. A Friedman’s palate position type IV was characterized as lack of visualization of the soft palate with the mouth open and the tongue resting inside the mouth (Fig. 1) [8,9]. The number of nightly sleep hours was assessed by self-report with the question: “during the past month, how many hours on average did you sleep each night?” The Epworth sleepiness scale consists of eight questions rated on a four point Likert scale ranging from 0
(no chance of falling asleep) to 3 (high chance of falling asleep) with a maximum total score of 24; a score ≥10 was considered positive [7]. Using a logistic regression model, we evaluated the association between a positive result in the Epworth sleepiness scale and the presence of significant nasal septum deflection, mandibular retrognathia and a Friedman’s palate position type IV. The model was adjusted for age, sex, body mass index (BMI), and nightly sleep hours. Univariate and multivariate analysis were performed with an Epworth sleepiness scale ≥10 as the dependent variable. All analyses were performed using STATA software version 13 (STATA Corp, College Station, TX). 3. Results The census identified 688 Atahualpa residents aged ≥40 years, of whom 23 declined to participate. Mean age of the remaining 665 persons was 59.5 ± 12.6 years, 58% were women, mean BMI was 26.9 ± 4.9 kg/m2 , and mean nightly sleep hours was 7.2 ± 1.2. The Epworth sleepiness scale was ≥10 in 155 persons (23%), 98 (15%) had nasal septum deflection, 47 (7%) had mandibular retrognathia and 528 (79%) had a Friedman’s palate position type IV. Persons with Epworth sleepiness scale scores ≥10 were older than those with scores <10, but the percentage of women, mean values of BMI, and nightly sleep hours were similar across both groups. In a logistic regression model, after adjusting for age, sex, BMI and nightly sleep hours, persons with nasal septum deflection were twice as likely to have an Epworth sleepiness scale score ≥10 (p = 0.009). Mandibular retrognathia and a Friedman’s palate position type IV were not associated with EDS, nor did they further increase the risk for EDS in persons with deflection of the nasal septum (Table 1). 4. Discussion This study shows that Ecuadorian Natives/Mestizos with nasal septum deflection are twice as likely to have EDS,
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292
291
Table 1 Summary of findings in 665 Atahualpa residents aged ≥40 years according to the results in the Epworth sleepiness scale. Total series N (665)
Epworth positive (n = 155)
Epworth negative (n = 510)
Significance
Age, years (mean ± SD) Women, % BMI, kg/m2 (mean ± SD) Nightly sleep hours (mean ± SD) Nasal septum deflection, n%
58.5 ± 12.6 58 26.9 ± 4.9 7.2 ± 1.2 98 (14.7%)
61.8 ± 13.7 57 26.3 ± 5.3 7.3 ± 1.5 34 (21.9%)
58.8 ± 12.2 58 27.1 ± 4.7 7.1 ± 1.2 64 (12.5%)
Mandibular retrognathia, n%
47 (7.1%)
11 (7.1%)
36 (7.1%)
Friedman’s palate position type IV, n%
528 (79.4%)
122 (78.7%)
406 (79.6%)
p = 0.009* p = 0.86 p = 0.07 p = 0.08 OR: 1.9, 95% C.I.: 1.2–3.1, p = 0.009a,b OR: 1.1, 95% C.I.: 0.5–2.2 p = 0.81b OR: 1.00 95% C.I.: 0.6–1.6 p = 0.99b
a b
Statistically significant result. Logistic regression model (univariate), after adjustment for age, sex, BMI, and nightly sleep hours.
after adjusting for a number of confounding variables. The other two investigated characteristics of facial morphology (mandibular retrognathia and a Friedman’s palate position type IV) were linked alone or in combination, nor did they further increase the risk for EDS in persons with nasal septum deflection. We used anterior rhinoscopy and visual inspection of external nasal deformities (rather than imaging studies) for characterizing the nasal septum. Inspection can miss intrusions into the nasal lumen beyond the nasal valve region, and this is a limitation of the present study. However, a good correlation has been reported between subjective nasal obstruction and assessment with rhinomanometry [10]. Therefore, the criteria we used to classify nasal septum deflection as significant likely allowed us to capture those cases with true nasal flow obstruction. The door-to-door design, the homogeneous characteristics of Atahualpa’s residents and the model used for evaluation of variables across persons with and without EDS, also argues for the strength of our results. Variants or abnormalities in craniofacial structures play a role in the pathogenesis of OSA by causing changes in airflow velocity and resistance, leading to reduction or transient cessation of air flow. A population-based survey (involving workers of State agencies in the Wisconsin area) showed links between nasal obstruction, snoring and EDS [11]. A two- to three-fold increased risk of EDS was found in patients with a deflected septum consulting for corrective nasal surgery and in persons with chronic nasal obstruction referred to sleep clinics for possible OSA [3–5]. Although we observed a significant association between EDS and nasal septum deflection, we were unable to document any association with mandibular retrognathia or the presence of a Friedman’s palate position type IV. The former could be because of the low prevalence of mandibular retrognathia in the cohort (7%), together with the possibility that mandibular retrognathia may be only marginally related to OSA [4]. The high prevalence of a Friedman’s palate position type IV in Ecuadorian Natives/Mestizos (79%) may be
genetically determined since Amerindians have a predominantly elliptic hard palate [12]. Such high prevalence might have masked any marginal difference in this relatively small population. In summary, our results suggest that nasal septum deflection is associated with EDS in Ecuadorian Natives/Mestizos. Early detection of persons with EDS and at risk of OSA is of particular interest because patients with OSA who have EDS are more prone to develop adverse vascular events [13]. Identifying those with nasal septum deflection is a potentially cost-effective method of detecting persons at risk of OSA. Authors’ contributions P.R.C. and O.H.D.: design of the study, drafting the manuscript; R.M.M.: statistical analysis, drafting the manuscript; M.Z.: data collection and analysis. Conflicts of interest Nothing to disclose. External funding This study was partially supported by an unrestricted grant from Universidad Espíritu Santo – Ecuador, Guayaquil – Ecuador.
References [1] X. Wang, Y. Ouyang, Z. Wang, G. Zhao, L. Liu, Y. Bi, Obstructive sleep apnea and risk of cardiovascular disease and all-cause mortality: a meta-analysis of prospective cohort studies, Int. J. Cardiol. 169 (2013) 207–214. [2] P.M. Lavados, A.J. Hennis, J.G. Fernandes, M.T. Medina, B. Legetic, A. Hoppe, L. Jadue, R. Salinas, Stroke epidemiology, prevention, and
292
[3]
[4]
[5]
[6]
[7]
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292 management strategies at a regional level: Latin America and the Caribbean, Lancet Neurol. 6 (2007) 362–372. L. Ishii, A. Godoy, S.L. Ishman, C.G. Gourin, M. Ishii, The nasal obstruction symptom evaluation survey as a screening tool for obstructive sleep apnea, Arch. Otolaryngol. Head Neck Surg. 137 (2011) 119–123. J. Dahlqvist, A. Dahlqvist, M. Marklund, D. Berggren, H. Stenlund, K.A. Franklin, Physical findings in the upper airway related to obstructive sleep apnea in men and women, Acta Otolaryngol. 127 (2007) 623–630. F. Lofaso, A. Coste, M.P. d’Ortho, F. Zerah-Lancner, C. Delclaux, F. Goldenberg, A. Harf, Nasal obstruction as a risk factor for sleep apnoea syndrome, Eur. Respir. J. 16 (2000) 639–643. O.H. Del Brutto, R.M. Mera, R. Farfán, P.R. Castillo, Cerebrovascular correlates of sleep disorders – rational and protocol of a door-to-door survey in rural coastal Ecuador, J. Stroke Cerebrovasc. Dis. (2013), http://dx.doi.org/10.1016/j.strokecerebrovasdis.2013.08.020 M.W. Johns, A new method for measuring daytime sleepiness: the Epworth sleepiness scale, Sleep 14 (1991) 540–545.
[8] M. Friedman, H. Ibrahim, L. Bass, Clinical staging for sleepdisordered breathing, Otolaryngol. Head Neck Surg. 127 (2002) 13–21. [9] A.V. Shelgikar, R. Chervin, Approach to and evaluation of sleep disorders, Continuum (Minneap Minn) 19 (2013) 32–49. [10] S. Savovic, M. Smajic, S. Molnar, L. Jovancevic, M. Buljcik-Cupic, V. Kljajic, V. Pilija, Correlation between subjective and objective nasal breathing assessments in examinees with nasal septum deformities, Vojnosanit. Pregl. 70 (2013) 380–385. [11] T. Young, L. Finn, M. Palta, Chronic nasal congestion at night is a risk factor for snoring in a population-based cohort study, Arch. Intern. Med. 161 (2001) 1514–1519. [12] G.W. Gill, Craniofacial criteria in the skeletal attribution of race, in: K.J. Reichs (Ed.), Forensic Osteology, 2nd ed., Charles C. Thomas, Springfield, IL, 1998, pp. 293–315. [13] J. Feng, Q.Y. He, X.L. Zhang, B.Y. Chen, Epworth sleepiness scale may be an indicator for blood pressure profile and prevalence of coronary artery disease and cerebrovascular disease in patients with obstructive sleep apnea, Sleep Breath. 16 (2012) 31–40.
Population-based study of facial morphology and excessive daytime somnolence Pablo R. Castillo a,1 , Robertino M. Mera b , Mauricio Zambrano c , Oscar H. Del Brutto d,∗,1 a
Sleep Disorders Center, Mayo Clinic College of Medicine, Jacksonville, FL, United States b Gastroenterology Department, Vanderbilt University, Nashville, TN, United States c Community Center, Atahualpa, Ecuador d School of Medicine, Universidad Espíritu Santo – Ecuador, Guayaquil, Ecuador Received 14 May 2014; received in revised form 23 May 2014; accepted 6 June 2014
Abstract Studies in patients seeking attention for nasal obstruction or pharyngeal disorders suggest that craniofacial abnormalities correlate with obstructive sleep apnea, but there is little information on the relevance of this association in the population at large. We aimed to determine whether characteristics of facial morphology correlate with excessive daytime somnolence (EDS) in a population-based, door-to-door survey. Residents of a village in rural Ecuador were screened with the Epworth sleepiness scale to assess EDS and underwent physical examination with attention to nasal septum deflection, mandibular retrognathia and presence of Friedman’s palate position type IV. From 665 participants aged ≥40 years, 155 had EDS, 98 had nasal septum deflection, 47 had mandibular retrognathia and 528 had a Friedman’s palate position type IV. In a logistic regression model adjusted for age, sex, body mass index, and nightly sleep hours, persons with nasal septum deflection were twice as likely to have EDS (p = 0.009). The other two variables were not associated with EDS. Identification of nasal septum deflection may be a cost-effective method of detecting persons at risk for obstructive sleep apnea in remote areas where sophisticated technology is not readily available. © 2014 Elsevier Ireland Ltd. All rights reserved.
Keywords: Obstructive sleep apnea; Daytime somnolence; Nasal septum deflection; Nasal septum deviation; Ecuador
1. Introduction Obstructive sleep apnea (OSA) is a common medical condition that decreases quality of life and increases cardiovascular risk, stroke incidence, and all-cause mortality [1]. Conservative figures suggest that 10% of adults worldwide have OSA, but this condition remains undetected in rural areas of developing countries, where technology needed for its definitive diagnosis is not readily available. To reduce the increasing burden of cardiovascular diseases in rural areas of low- and middle-income countries, ∗ Corresponding author at: Air Center 3542, PO Box 522970, Miami, FL 33152-2970, United States. Tel.: +1 59342285790. E-mail address: [email protected] (O.H. Del Brutto). 1 These authors contributed equally to this work.
http://dx.doi.org/10.1016/j.pathophys.2014.06.001 0928-4680/© 2014 Elsevier Ireland Ltd. All rights reserved.
implementation of cost-effective strategies such as recognition of modifiable risk factors – including OSA – is mandatory [2]. In these regions, mass screening with field instruments designed to detect persons with probably OSA may be complicated by cross-cultural factors and illiteracy. There is a need for reliable screening tools to facilitate early detection of persons with risk of OSA in underserved populations. Although the relationship between abnormal craniofacial characteristics and OSA has been documented in patients seeking attention for sleep-disordered breathing or a specific nasal or pharyngeal disorder [3–5], little is known about the relevance of this association in the population at large, particularly in underserved populations. We report the findings of a population-based study in rural Ecuador, designed to evaluate characteristics of facial morphology and to determine whether they can identify
290
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292
Fig. 1. Study subjects with nasal septum deflection (left), mandibular retrognathia (center), and Friedman palate position type IV (right).
persons at risk of OSA who should be referred for further evaluation. 2. Methods The IRB of Hospital-Clínica Kennedy, Guayaquil, Ecuador (FWA00006867), approved the protocol and informed consent forms. Atahualpa is located in coastal Ecuador, and is representative of the rural villages of the region. More than 95% of the population belongs to the Ecuadorian Native/Mestizo ethnic group (Amerindians). Phenotypically, these persons are of short stature and most have abdominal obesity. The Atahualpa Project is a population-based cohort study that evaluates the relationships between sleep disorders and cardiovascular risk factors in rural Ecuador. Methodology has been detailed elsewhere [6]. For this part of the study, trained field personnel conducted a door-to-door survey to identify all Atahualpa residents aged ≥40 years. Consenting persons underwent a physical examination with attention to the height, weight, and characteristics of facial morphology that have been associated with an increased risk of OSA, including nasal septum deflection, mandibular retrognathia, and a Friedman’s palate position type IV. We also assessed the number of nightly sleep hours and the presence of excessive daytime somnolence (EDS) (used as a proxy for OSA) by the use of the Epworth sleepiness scale [7]. Nasal septum deflection was characterized as significant when it was deviated ≥5 mm away from the midline causing external nasal deformity and associated with subjective report of nasal flow. Mandibular retrognathia was categorized as present when the anterior prominence of the chin was ≥2 mm behind a virtual line drawn from the vermillion border of the lower lip to the chin. A Friedman’s palate position type IV was characterized as lack of visualization of the soft palate with the mouth open and the tongue resting inside the mouth (Fig. 1) [8,9]. The number of nightly sleep hours was assessed by self-report with the question: “during the past month, how many hours on average did you sleep each night?” The Epworth sleepiness scale consists of eight questions rated on a four point Likert scale ranging from 0
(no chance of falling asleep) to 3 (high chance of falling asleep) with a maximum total score of 24; a score ≥10 was considered positive [7]. Using a logistic regression model, we evaluated the association between a positive result in the Epworth sleepiness scale and the presence of significant nasal septum deflection, mandibular retrognathia and a Friedman’s palate position type IV. The model was adjusted for age, sex, body mass index (BMI), and nightly sleep hours. Univariate and multivariate analysis were performed with an Epworth sleepiness scale ≥10 as the dependent variable. All analyses were performed using STATA software version 13 (STATA Corp, College Station, TX). 3. Results The census identified 688 Atahualpa residents aged ≥40 years, of whom 23 declined to participate. Mean age of the remaining 665 persons was 59.5 ± 12.6 years, 58% were women, mean BMI was 26.9 ± 4.9 kg/m2 , and mean nightly sleep hours was 7.2 ± 1.2. The Epworth sleepiness scale was ≥10 in 155 persons (23%), 98 (15%) had nasal septum deflection, 47 (7%) had mandibular retrognathia and 528 (79%) had a Friedman’s palate position type IV. Persons with Epworth sleepiness scale scores ≥10 were older than those with scores <10, but the percentage of women, mean values of BMI, and nightly sleep hours were similar across both groups. In a logistic regression model, after adjusting for age, sex, BMI and nightly sleep hours, persons with nasal septum deflection were twice as likely to have an Epworth sleepiness scale score ≥10 (p = 0.009). Mandibular retrognathia and a Friedman’s palate position type IV were not associated with EDS, nor did they further increase the risk for EDS in persons with deflection of the nasal septum (Table 1). 4. Discussion This study shows that Ecuadorian Natives/Mestizos with nasal septum deflection are twice as likely to have EDS,
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292
291
Table 1 Summary of findings in 665 Atahualpa residents aged ≥40 years according to the results in the Epworth sleepiness scale. Total series N (665)
Epworth positive (n = 155)
Epworth negative (n = 510)
Significance
Age, years (mean ± SD) Women, % BMI, kg/m2 (mean ± SD) Nightly sleep hours (mean ± SD) Nasal septum deflection, n%
58.5 ± 12.6 58 26.9 ± 4.9 7.2 ± 1.2 98 (14.7%)
61.8 ± 13.7 57 26.3 ± 5.3 7.3 ± 1.5 34 (21.9%)
58.8 ± 12.2 58 27.1 ± 4.7 7.1 ± 1.2 64 (12.5%)
Mandibular retrognathia, n%
47 (7.1%)
11 (7.1%)
36 (7.1%)
Friedman’s palate position type IV, n%
528 (79.4%)
122 (78.7%)
406 (79.6%)
p = 0.009* p = 0.86 p = 0.07 p = 0.08 OR: 1.9, 95% C.I.: 1.2–3.1, p = 0.009a,b OR: 1.1, 95% C.I.: 0.5–2.2 p = 0.81b OR: 1.00 95% C.I.: 0.6–1.6 p = 0.99b
a b
Statistically significant result. Logistic regression model (univariate), after adjustment for age, sex, BMI, and nightly sleep hours.
after adjusting for a number of confounding variables. The other two investigated characteristics of facial morphology (mandibular retrognathia and a Friedman’s palate position type IV) were linked alone or in combination, nor did they further increase the risk for EDS in persons with nasal septum deflection. We used anterior rhinoscopy and visual inspection of external nasal deformities (rather than imaging studies) for characterizing the nasal septum. Inspection can miss intrusions into the nasal lumen beyond the nasal valve region, and this is a limitation of the present study. However, a good correlation has been reported between subjective nasal obstruction and assessment with rhinomanometry [10]. Therefore, the criteria we used to classify nasal septum deflection as significant likely allowed us to capture those cases with true nasal flow obstruction. The door-to-door design, the homogeneous characteristics of Atahualpa’s residents and the model used for evaluation of variables across persons with and without EDS, also argues for the strength of our results. Variants or abnormalities in craniofacial structures play a role in the pathogenesis of OSA by causing changes in airflow velocity and resistance, leading to reduction or transient cessation of air flow. A population-based survey (involving workers of State agencies in the Wisconsin area) showed links between nasal obstruction, snoring and EDS [11]. A two- to three-fold increased risk of EDS was found in patients with a deflected septum consulting for corrective nasal surgery and in persons with chronic nasal obstruction referred to sleep clinics for possible OSA [3–5]. Although we observed a significant association between EDS and nasal septum deflection, we were unable to document any association with mandibular retrognathia or the presence of a Friedman’s palate position type IV. The former could be because of the low prevalence of mandibular retrognathia in the cohort (7%), together with the possibility that mandibular retrognathia may be only marginally related to OSA [4]. The high prevalence of a Friedman’s palate position type IV in Ecuadorian Natives/Mestizos (79%) may be
genetically determined since Amerindians have a predominantly elliptic hard palate [12]. Such high prevalence might have masked any marginal difference in this relatively small population. In summary, our results suggest that nasal septum deflection is associated with EDS in Ecuadorian Natives/Mestizos. Early detection of persons with EDS and at risk of OSA is of particular interest because patients with OSA who have EDS are more prone to develop adverse vascular events [13]. Identifying those with nasal septum deflection is a potentially cost-effective method of detecting persons at risk of OSA. Authors’ contributions P.R.C. and O.H.D.: design of the study, drafting the manuscript; R.M.M.: statistical analysis, drafting the manuscript; M.Z.: data collection and analysis. Conflicts of interest Nothing to disclose. External funding This study was partially supported by an unrestricted grant from Universidad Espíritu Santo – Ecuador, Guayaquil – Ecuador.
References [1] X. Wang, Y. Ouyang, Z. Wang, G. Zhao, L. Liu, Y. Bi, Obstructive sleep apnea and risk of cardiovascular disease and all-cause mortality: a meta-analysis of prospective cohort studies, Int. J. Cardiol. 169 (2013) 207–214. [2] P.M. Lavados, A.J. Hennis, J.G. Fernandes, M.T. Medina, B. Legetic, A. Hoppe, L. Jadue, R. Salinas, Stroke epidemiology, prevention, and
292
[3]
[4]
[5]
[6]
[7]
P.R. Castillo et al. / Pathophysiology 21 (2014) 289–292 management strategies at a regional level: Latin America and the Caribbean, Lancet Neurol. 6 (2007) 362–372. L. Ishii, A. Godoy, S.L. Ishman, C.G. Gourin, M. Ishii, The nasal obstruction symptom evaluation survey as a screening tool for obstructive sleep apnea, Arch. Otolaryngol. Head Neck Surg. 137 (2011) 119–123. J. Dahlqvist, A. Dahlqvist, M. Marklund, D. Berggren, H. Stenlund, K.A. Franklin, Physical findings in the upper airway related to obstructive sleep apnea in men and women, Acta Otolaryngol. 127 (2007) 623–630. F. Lofaso, A. Coste, M.P. d’Ortho, F. Zerah-Lancner, C. Delclaux, F. Goldenberg, A. Harf, Nasal obstruction as a risk factor for sleep apnoea syndrome, Eur. Respir. J. 16 (2000) 639–643. O.H. Del Brutto, R.M. Mera, R. Farfán, P.R. Castillo, Cerebrovascular correlates of sleep disorders – rational and protocol of a door-to-door survey in rural coastal Ecuador, J. Stroke Cerebrovasc. Dis. (2013), http://dx.doi.org/10.1016/j.strokecerebrovasdis.2013.08.020 M.W. Johns, A new method for measuring daytime sleepiness: the Epworth sleepiness scale, Sleep 14 (1991) 540–545.
[8] M. Friedman, H. Ibrahim, L. Bass, Clinical staging for sleepdisordered breathing, Otolaryngol. Head Neck Surg. 127 (2002) 13–21. [9] A.V. Shelgikar, R. Chervin, Approach to and evaluation of sleep disorders, Continuum (Minneap Minn) 19 (2013) 32–49. [10] S. Savovic, M. Smajic, S. Molnar, L. Jovancevic, M. Buljcik-Cupic, V. Kljajic, V. Pilija, Correlation between subjective and objective nasal breathing assessments in examinees with nasal septum deformities, Vojnosanit. Pregl. 70 (2013) 380–385. [11] T. Young, L. Finn, M. Palta, Chronic nasal congestion at night is a risk factor for snoring in a population-based cohort study, Arch. Intern. Med. 161 (2001) 1514–1519. [12] G.W. Gill, Craniofacial criteria in the skeletal attribution of race, in: K.J. Reichs (Ed.), Forensic Osteology, 2nd ed., Charles C. Thomas, Springfield, IL, 1998, pp. 293–315. [13] J. Feng, Q.Y. He, X.L. Zhang, B.Y. Chen, Epworth sleepiness scale may be an indicator for blood pressure profile and prevalence of coronary artery disease and cerebrovascular disease in patients with obstructive sleep apnea, Sleep Breath. 16 (2012) 31–40.