title: Cross-Sectional Comparison of Sleep-Disordered Breathing in Native Peruvian Highlanders and Lowlanders.
abstract: Pham, Luu V., Christopher Meinzen, Rafael S. Arias, Noah G. Schwartz, Adi Rattner, Catherine H. Miele, Philip L. Smith, Hartmut Schneider, J. Jaime Miranda, Robert H. Gilman, Vsevolod Y. Polotsky, William Checkley, and Alan R. Schwartz. Cross-sectional comparison of sleep-disordered breathing in native Peruvian highlanders and lowlanders. High Alt Med Biol. 18:11-19, 2017.
  
  
  BACKGROUND
  Altitude can accentuate sleep disordered breathing (SDB), which has been linked to cardiovascular and metabolic diseases. SDB in highlanders has not been characterized in large controlled studies. The purpose of this study was to compare SDB prevalence and severity in highlanders and lowlanders.
  
  
  METHODS
  170 age-, body-mass-index- (BMI), and sex-matched pairs (age 58.2 ± 12.4 years, BMI 27.2 ± 3.5 kg/m2, and 86 men and 84 women) of the CRONICAS Cohort Study were recruited at a sea-level (Lima) and a high-altitude (Puno, 3825 m) setting in Peru. Participants underwent simultaneous nocturnal polygraphy and actigraphy to characterize breathing patterns, movement arousals, and sleep/wake state. We compared SDB prevalence, type, and severity between highlanders and lowlanders as measured by apnea-hypopnea index (AHI) and pulse oximetry (SPO2) during sleep.
  
  
  RESULTS
  Sleep apnea prevalence was greater in highlanders than in lowlanders (77% vs. 54%, p < 0.001). Compared with lowlanders, highlanders had twofold elevations in AHI due to increases in central rather than obstructive apneas. In highlanders compared with lowlanders, SPO2was lower during wakefulness and decreased further during sleep (p < 0.001). Hypoxemia during wakefulness predicted sleep apnea in highlanders, and it appears to mediate the effects of altitude on sleep apnea prevalence. Surprisingly, hypoxemia was also quite prevalent in lowlanders, and it was also associated with increased odds of sleep apnea.
  
  
  CONCLUSIONS
  High altitude and hypoxemia at both high and low altitude were associated with increased SDB prevalence and severity. Our findings suggest that a large proportion of highlanders remain at risk for SDB sequelae.
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Luu V
authors.initials: LV
authors.lastname: Pham
authors.affiliation: 2 Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Christopher
authors.initials: C
authors.lastname: Meinzen
authors.affiliation: 3 School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Rafael S
authors.initials: RS
authors.lastname: Arias
authors.affiliation: 4 University of Chicago Pritzker School of Medicine , Chicago, Illinois.
authors.forename: Noah G
authors.initials: NG
authors.lastname: Schwartz
authors.affiliation: 3 School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Adi
authors.initials: A
authors.lastname: Rattner
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Catherine H
authors.initials: CH
authors.lastname: Miele
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Philip L
authors.initials: PL
authors.lastname: Smith
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Hartmut
authors.initials: H
authors.lastname: Schneider
authors.affiliation: 5 School of Medicine, Universidad Peruana Cayetano Heredia , Lima, Peru .|6 CRONICAS Center of Excellence in Chronic Diseases, Universidad Peruana Cayetano Heredia , Lima, Peru .
authors.forename: J Jaime
authors.initials: JJ
authors.lastname: Miranda
authors.affiliation: 2 Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Robert H
authors.initials: RH
authors.lastname: Gilman
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Vsevolod Y
authors.initials: VY
authors.lastname: Polotsky
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.|2 Program in Global Disease Epidemiology and Control, Department of International Health, Bloomberg School of Public Health, Johns Hopkins University , Baltimore, Maryland.
authors.forename: William
authors.initials: W
authors.lastname: Checkley
authors.affiliation: 1 Division of Pulmonary and Critical Care and Sleep Medicine, Department of Medicine, School of Medicine, Johns Hopkins University , Baltimore, Maryland.
authors.forename: Alan R
authors.initials: AR
authors.lastname: Schwartz
mesh_terms: D000368:Aged; D000531:Altitude; D015992:Body Mass Index; D003430:Cross-Sectional Studies; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010092:Oximetry; D010568:Peru / Q000453:epidemiology / Q000208:ethnology; D015995:Prevalence; D011446:Prospective Studies; D012119:Respiration; D012307:Risk Factors; D012720:Severity of Illness Index; D012891:Sleep Apnea Syndromes / Q000453:epidemiology / Q000209:etiology / Q000503:physiopathology*
keywords: Andean; altitude; apnea; epidemiology; hypoxia