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Retinal microvasculature is a potential biomarker for acute mountain sickness. SCIENCE CHINA. LIFE SCIENCES 2023:10.1007/s11427-022-2271-x. [PMID: 36811802 DOI: 10.1007/s11427-022-2271-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/09/2022] [Accepted: 12/21/2022] [Indexed: 02/24/2023]
Abstract
Increased cerebral blood flow resulting from altered capillary level autoregulation at high altitudes leads to capillary overperfusion and then vasogenic cerebral edema, which is the leading hypothesis of acute mountain sickness (AMS). However, studies on cerebral blood flow in AMS have been mostly restricted to gross cerebrovascular endpoints as opposed to the microvasculature. This study aimed to investigate ocular microcirculation alterations, the only visualized capillaries in the central neural system (CNS), during early-stage AMS using a hypobaric chamber. This study found that after high altitude simulation, the optic nerve showed retinal nerve fiber layer thickening (P=0.004-0.018) in some locations, and the area of the optic nerve subarachnoid space (P=0.004) enlarged. Optical coherence tomography angiography (OCTA) showed increased retinal radial peripapillary capillary (RPC) flow density (P=0.003-0.046), particularly on the nasal side of the nerve. The AMS-positive group had the largest increases in RPC flow density in the nasal sector (AMS-positive, Δ3.21±2.37; AMS-negative, Δ0.01±2.16, P=0.004). Among multiple ocular changes, OCTA increase in RPC flow density was associated with simulated early-stage AMS symptoms (beta=0.222, 95%CI, 0.009-0.435, P=0.042). The area under the receiver operating characteristics curve (AUC) for the changes in RPC flow density to predict early-stage AMS outcomes was 0.882 (95%CI, 0.746-0.998). The results further confirmed that overperfusion of microvascular beds is the key pathophysiologic change in early-stage AMS. RPC OCTA endpoints may serve as a rapid, noninvasive potential biomarker for CNS microvascular changes and AMS development during risk assessment of individuals at high altitudes.
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Liu J, Yu F, Song H. Application of SARIMA model in forecasting and analyzing inpatient cases of acute mountain sickness. BMC Public Health 2023; 23:56. [PMID: 36624441 PMCID: PMC9827698 DOI: 10.1186/s12889-023-14994-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2022] [Accepted: 01/05/2023] [Indexed: 01/11/2023] Open
Abstract
BACKGROUND Acute Mountain Sickness (AMS) is typically triggered by hypoxia under high altitude conditions. Currently, rule of time among AMS inpatients was not clear. Thus, this study aimed to analyze the time distribution of AMS inpatients in the past ten years and construct a prediction model of AMS hospitalized cases. METHODS We retrospectively collected medical records of AMS inpatients admitted to the military hospitals from January 2009 to December 2018 and analyzed the time series characteristics. Seasonal Auto-Regressive Integrated Moving Average (SARIMA) was established through training data to finally forecast in the test data set. RESULTS A total of 22 663 inpatients were included in this study and recorded monthly, with predominant peak annually, early spring (March) and mid-to-late summer (July to August), respectively. Using the training data from January 2009 to December 2017, the model SARIMA (1, 1, 1) (1, 0, 1) 12 was employed to predict the test data from January 2018 to December 2018. In 2018, the total predicted value after adjustment was 9.24%, less than the actual value. CONCLUSION AMS inpatients have obvious periodicity and seasonality. The SARIMA model has good fitting ability and high short-term prediction accuracy. It can help explore the characteristics of AMS disease and provide decision-making basis for allocation of relevant medical resources for AMS inpatients.
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Affiliation(s)
- Jianchao Liu
- grid.414252.40000 0004 1761 8894Institute of Hospital Management, Department of Medical Innovation Research, PLA General Hospital, Beijing, 100853 China
| | - Fangfang Yu
- grid.414252.40000 0004 1761 8894Department of Medical Innovation Research, PLA General Hospital, Beijing, 100853 China
| | - Han Song
- grid.414252.40000 0004 1761 8894Department of Health Service, PLA General Hospital, No.28, Fuxing Road, Beijing, 100853 China
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André M, Brucato N, Plutniak S, Kariwiga J, Muke J, Morez A, Leavesley M, Mondal M, Ricaut FX. Phenotypic differences between highlanders and lowlanders in Papua New Guinea. PLoS One 2021; 16:e0253921. [PMID: 34288918 PMCID: PMC8294550 DOI: 10.1371/journal.pone.0253921] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2021] [Accepted: 06/16/2021] [Indexed: 12/13/2022] Open
Abstract
OBJECTIVES Altitude is one of the most demanding environmental pressures for human populations. Highlanders from Asia, America and Africa have been shown to exhibit different biological adaptations, but Oceanian populations remain understudied [Woolcock et al., 1972; Cotes et al., 1974; Senn et al., 2010]. We tested the hypothesis that highlanders phenotypically differ from lowlanders in Papua New Guinea, as a result of inhabiting the highest mountains in Oceania for at least 20,000 years. MATERIALS AND METHODS We collected data for 13 different phenotypes related to altitude for 162 Papua New Guineans living at high altitude (Mont Wilhelm, 2,300-2,700 m above sea level (a.s.l.) and low altitude (Daru, <100m a.s.l.). Multilinear regressions were performed to detect differences between highlanders and lowlanders for phenotypic measurements related to body proportions, pulmonary function, and the circulatory system. RESULTS Six phenotypes were significantly different between Papua New Guinean highlanders and lowlanders. Highlanders show shorter height (p-value = 0.001), smaller waist circumference (p-value = 0.002), larger Forced Vital Capacity (FVC) (p-value = 0.008), larger maximal (p-value = 3.20e -4) and minimal chest depth (p-value = 2.37e -5) and higher haemoglobin concentration (p-value = 3.36e -4). DISCUSSION Our study reports specific phenotypes in Papua New Guinean highlanders potentially related to altitude adaptation. Similar to other human groups adapted to high altitude, the evolutionary history of Papua New Guineans appears to have also followed an adaptive biological strategy for altitude.
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Affiliation(s)
- Mathilde André
- Estonian Biocentre, Institute of Genomics, University of Tartu, Tartu, Tartumaa, Estonia
| | - Nicolas Brucato
- Laboratoire Évolution and Diversité Biologique (EDB UMR5174), Université de Toulouse Midi-Pyrénées, CNRS, IRD, UPS, Toulouse, France
| | - Sébastien Plutniak
- Laboratoire Travaux et Recherches Archéologiques sur les Cultures, les Espaces et les Sociétés (TRACES, UMR 5608), Université Toulouse Jean Jaurès, Maison de la Recherche, Toulouse, France
| | - Jason Kariwiga
- Strand of Anthropology, Sociology and Archaeology, School of Humanities & Social Sciences, University of Papua New Guinea, National Capital District, Papua New Guinea
- School of Social Science, University of Queensland, Australia, St Lucia, Australia
| | - John Muke
- Social Research Institute Ltd, Port Moresby, Papua New Guinea
| | - Adeline Morez
- School of Biological and Environmental Sciences, Liverpool John Moores University, Liverpool, United Kingdom
| | - Matthew Leavesley
- Strand of Anthropology, Sociology and Archaeology, School of Humanities & Social Sciences, University of Papua New Guinea, National Capital District, Papua New Guinea
- ARC Centre of Excellence for Australian Biodiversity and Heritage, College of Arts, Society and Education, James Cook University, Cairns, Australia
| | - Mayukh Mondal
- Estonian Biocentre, Institute of Genomics, University of Tartu, Tartu, Tartumaa, Estonia
| | - François-Xavier Ricaut
- Laboratoire Évolution and Diversité Biologique (EDB UMR5174), Université de Toulouse Midi-Pyrénées, CNRS, IRD, UPS, Toulouse, France
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Wang Y, Xu M, Shi Y. Efficacy of spinal chiropractic manipulative therapy for adjusting the relationship between cervical facet joints to treat headache caused by acute mountain sickness. J Int Med Res 2020; 48:300060519898005. [PMID: 31948301 PMCID: PMC7113709 DOI: 10.1177/0300060519898005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Yuan Wang
- Department of Geriatrics, Beijing Geriatric Hospital, Beijing, China
| | - Mengzi Xu
- Department of Orthopedics, Beijing Haidian Hospital, Beijing, China
| | - Yan Shi
- Department of Orthopedics, Beijing Haidian Hospital, Beijing, China
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Siques P, Brito J, Schwedhelm E, Pena E, León-Velarde F, De La Cruz JJ, Böger RH, Hannemann J. Asymmetric Dimethylarginine at Sea Level Is a Predictive Marker of Hypoxic Pulmonary Arterial Hypertension at High Altitude. Front Physiol 2019; 10:651. [PMID: 31191349 PMCID: PMC6545974 DOI: 10.3389/fphys.2019.00651] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2019] [Accepted: 05/08/2019] [Indexed: 12/18/2022] Open
Abstract
Background: Prolonged exposure to altitude-associated chronic hypoxia (CH) may cause high-altitude pulmonary hypertension (HAPH). Chronic intermittent hypobaric hypoxia (CIH) occurs in individuals who commute between sea level and high altitude. CIH is associated with repetitive acute hypoxic acclimatization and conveys the long-term risk of HAPH. As nitric oxide (NO) regulates pulmonary vascular tone and asymmetric dimethylarginine (ADMA) is an endogenous inhibitor of NO synthesis, we investigated whether ADMA concentration at sea level predicts HAPH among Chilean frontiers personnel exposed to 6 months of CIH. Methods: In this prospective study, 123 healthy army draftees were subjected to CIH (5 days at 3,550 m, 2 days at sea level) for 6 months. In 100 study participants with complete data, ADMA, symmetric dimethylarginine (SDMA), L-arginine, arterial oxygen saturation (SaO2), systemic blood pressure, and hematocrit were assessed at months 0 (sea level), 1, 4, and 6. Acclimatization to altitude was determined using the Lake Louise Score (LLS) and the presence of acute mountain sickness (AMS). Echocardiography was performed after 6 months of CIH in 43 individuals with either good (n = 23) or poor (n = 20) acclimatization. Results: SaO2 acutely decreased at altitude and plateaued at 90% thereafter. ADMA increased and SDMA decreased during the study course. The incidence of AMS and the LLS was high after the first ascent (53 and 3.1 ± 2.4) and at 1 month of CIH (47 and 3.0 ± 2.6), but decreased to 20 and 1.4 ± 2.0 at month 6 (both p < 0.001). Eighteen participants (42%) showed a mean pulmonary arterial pressure (mPAP) >25 mm Hg, out of which 9 (21%) were classified as HAPH (mPAP ≥ 30 mm Hg). ADMA at sea level was significantly associated with mPAP at high altitude in month 6 (R = 0.413; p = 0.007). In ROC analysis, a cutoff for baseline ADMA of 0.665 μmol/L was determined to predict HAPH (mPAP > 30 mm Hg) with a sensitivity of 100% and a specificity of 63.6%. Conclusions: ADMA concentration increases during CIH. ADMA at sea level is an independent predictive biomarker of HAPH. SDMA concentration decreases during CIH and shows no association with HAPH. Our data support a role of impaired NO-mediated pulmonary vasodilation in the pathogenesis of HAPH.
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Affiliation(s)
- Patricia Siques
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile
| | - Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile
| | - Edzard Schwedhelm
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Eduardo Pena
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile.,Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile
| | - Fabiola León-Velarde
- Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile.,Department of Biological and Physiological Sciences, Facultad de Ciencias y Filosofía, Universidad Peruana Cayetano Heredia, Lima, Peru
| | - Juan José De La Cruz
- Department of Preventive Medicine and Public Health, Universidad Autónoma de Madrid, Madrid, Spain
| | - Rainer H Böger
- Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile.,Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Juliane Hannemann
- Institute DECIPHER, German-Chilean Institute for Research on Pulmonary Hypoxia and its Health Sequelae, Hamburg, Germany and Iquique, Chile.,Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Brito J, Siques P, López R, Romero R, León-Velarde F, Flores K, Lüneburg N, Hannemann J, Böger RH. Long-Term Intermittent Work at High Altitude: Right Heart Functional and Morphological Status and Associated Cardiometabolic Factors. Front Physiol 2018; 9:248. [PMID: 29623044 PMCID: PMC5874329 DOI: 10.3389/fphys.2018.00248] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2017] [Accepted: 03/06/2018] [Indexed: 12/14/2022] Open
Abstract
Background: Living at high altitude or with chronic hypoxia implies functional and morphological changes in the right ventricle and pulmonary vasculature with a 10% prevalence of high-altitude pulmonary hypertension (HAPH). The implications of working intermittently (day shifts) at high altitude (hypobaric hypoxia) over the long term are still not well-defined. The aim of this study was to evaluate the right cardiac circuit status along with potentially contributory metabolic variables and distinctive responses after long exposure to the latter condition. Methods: A cross-sectional study of 120 healthy miners working at an altitude of 4,400-4,800 m for over 5 years in 7-day commuting shifts was designed. Echocardiography was performed on day 2 at sea level. Additionally, biomedical and biochemical variables, Lake Louise scores (LLSs), sleep disturbances and physiological variables were measured at altitude and at sea level. Results: The population was 41.8 ± 0.7 years old, with an average of 14 ± 0.5 (range 5-29) years spent at altitude. Most subjects still suffered from mild to moderate symptoms of acute mountain sickness (mild was an LLS of 3-5 points, including cephalea; moderate was LLS of 6-10 points) (38.3%) at the end of day 1 of the shift. Echocardiography showed a 23% mean pulmonary artery pressure (mPAP) >25 mmHg, 9% HAPH (≥30 mmHg), 85% mild increase in right ventricle wall thickness (≥5 mm), 64% mild right ventricle dilation, low pulmonary vascular resistance (PVR) and fairly good ventricle performance. Asymmetric dimethylarginine (ADMA) (OR 8.84 (1.18-66.39); p < 0.05) and insulin (OR: 1.11 (1.02-1.20); p < 0.05) were associated with elevated mPAP and were defined as a cut-off. Interestingly, the correspondence analysis identified association patterns of several other variables (metabolic, labor, and biomedical) with higher mPAP. Conclusions: Working intermittently at high altitude involves a distinctive pattern. The most relevant and novel characteristics are a greater prevalence of elevated mPAP and HAPH than previously reported at chronic intermittent hypobaric hypoxia (CIHH), which is accompanied by subsequent morphological characteristics. These findings are associated with cardiometabolic factors (insulin and ADMA). However, the functional repercussions seem to be minor or negligible. This research contributes to our understanding and surveillance of this unique model of chronic intermittent high-altitude exposure.
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Affiliation(s)
- Julio Brito
- Institute of Health Studies, University Arturo Prat, Iquique, Chile
| | - Patricia Siques
- Institute of Health Studies, University Arturo Prat, Iquique, Chile
| | - Rosario López
- Department of Preventive Medicine and Public Health, University Autonoma of Madrid, Madrid, Spain
| | - Raul Romero
- Institute of Health Studies, University Arturo Prat, Iquique, Chile
| | - Fabiola León-Velarde
- Department of Biological and Physiological Sciences, Facultad de Ciencias y Filosofía/IIA, University Peruana Cayetano Heredia, Lima, Peru
| | - Karen Flores
- Institute of Health Studies, University Arturo Prat, Iquique, Chile
| | - Nicole Lüneburg
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Juliane Hannemann
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
| | - Rainer H Böger
- Institute of Clinical Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany
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Meier D, Collet TH, Locatelli I, Cornuz J, Kayser B, Simel DL, Sartori C. Does This Patient Have Acute Mountain Sickness?: The Rational Clinical Examination Systematic Review. JAMA 2017; 318:1810-1819. [PMID: 29136449 DOI: 10.1001/jama.2017.16192] [Citation(s) in RCA: 63] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
IMPORTANCE Acute mountain sickness (AMS) affects more than 25% of individuals ascending to 3500 m (11 500 ft) and more than 50% of those above 6000 m (19 700 ft). AMS may progress from nonspecific symptoms to life-threatening high-altitude cerebral edema in less than 1% of patients. It is not clear how to best diagnose AMS. OBJECTIVE To systematically review studies assessing the accuracy of AMS diagnostic instruments, including the visual analog scale (VAS) score, which quantifies the overall feeling of sickness at altitude (VAS[O]; various thresholds), Acute Mountain Sickness-Cerebral score (AMS-C; ≥0.7 indicates AMS), and the clinical functional score (CFS; ≥2 indicates AMS) compared with the Lake Louise Questionnaire Score (LLQS; score of ≥5). DATA EXTRACTION AND SYNTHESIS Searches of MEDLINE and EMBASE from inception to May 2017 identified 1245 publications of which 91 were suitable for prevalence analysis (66 944 participants) and 14 compared at least 2 instruments (1858 participants) using a score of 5 or greater on the LLQS as a reference standard. To determine the prevalence of AMS for establishing the pretest probability of AMS, a random-effects meta-regression was performed based on the reported prevalence of AMS as a function of altitude. MAIN OUTCOMES AND MEASURES AMS prevalence, likelihood ratios (LRs), sensitivity, and specificity of screening instruments. RESULTS The final analysis included 91 articles (comprising 66 944 study participants). Altitude predicted AMS and accounted for 28% of heterogeneity between studies. For each 1000-m (3300-ft) increase in altitude above 2500 m (8200 ft), AMS prevalence increased 13% (95% CI, 9.5%-17%). Testing characteristics were similar for VAS(O), AMS-C, and CFS vs a score of 5 or greater on the LLQS (positive LRs: range, 3.2-8.2; P = .22 for comparisons; specificity range, 67%-92%; negative LRs: range, 0.30-0.36; P = .50 for comparisons; sensitivity range, 67%-82%). The CFS asks a single question: "overall if you had any symptoms, how did they affect your activity (ordinal scale 0-3)?" For CFS, moderate to severe reduction in daily activities had a positive LR of 3.2 (95% CI, 1.4-7.2) and specificity of 67% (95% CI, 37%-97%); no reduction to mild reduction in activities had a negative LR of 0.30 (95% CI, 0.22-0.39) and sensitivity of 82% (95% CI, 77%-87%). CONCLUSIONS AND RELEVANCE The prevalence of acute mountain sickness increases with higher altitudes. The visual analog scale for the overall feeling of sickness at altitude, Acute Mountain Sickness-Cerebral, and clinical functional score perform similarly to the Lake Louise Questionnaire Score using a score of 5 or greater as a reference standard. In clinical and travel settings, the clinical functional score is the simplest instrument to use. Clinicians evaluating high-altitude travelers who report moderate to severe limitations in activities of daily living (clinical functional score ≥2) should use the Lake Louise Questionnaire Score to assess the severity of acute mountain sickness.
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Affiliation(s)
- David Meier
- Service of Internal Medicine, Lausanne University Hospital, Lausanne, Switzerland
| | - Tinh-Hai Collet
- Service of Endocrinology, Diabetes, and Metabolism, Lausanne University Hospital, Lausanne, Switzerland
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Isabella Locatelli
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Jacques Cornuz
- Ambulatory Care and Community Medicine, University of Lausanne; Lausanne, Switzerland
| | - Bengt Kayser
- Institute of Sports Sciences, University of Lausanne, Lausanne, Switzerland
| | - David L Simel
- Department of Medicine, Durham VA Medical Center, Durham, North Carolina
- Department of Medicine, Duke University Health System, Durham, North Carolina
| | - Claudio Sartori
- Service of Internal Medicine, Lausanne University Hospital, Lausanne, Switzerland
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Gonggalanzi, Labasangzhu, Bjertness E, Wu T, Stigum H, Nafstad P. Acute mountain sickness, arterial oxygen saturation and heart rate among Tibetan students who reascend to Lhasa after 7 years at low altitude: a prospective cohort study. BMJ Open 2017; 7:e016460. [PMID: 28698346 PMCID: PMC5726117 DOI: 10.1136/bmjopen-2017-016460] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/24/2023] Open
Abstract
Objectives The aim of the present study was to estimate the incidence of acute mountain sickness (AMS) and address the changes in arterial oxygen saturation (SaO2) and heart rate (HR) in native Tibetans who reascend to the high-altitude city of Lhasa (3658 m) after a 7-year stay at low altitude. Methods We followed two cohorts of students aged 17–21 years (859 Native Tibetan and 801 Han Chinese), travelling from lowland China until 3 days after their arrival in highland city of Lhasa. Questionnaire information of the symptoms of AMS using the Lake Louise Scoring System, resting SaO2 and HR were assessed both before leaving the lowland and after arriving in Lhasa. Linear regression was performed to compare changes in SaO2 and HR levels from low to high altitude in Tibetan and Han Chinese. Results New cases of AMS occurred in only 1.2% (95% CI 0.4% to 2.0%) of the Tibetan students who came to Lhasa by train compared with 32.7% (95% CI 28.0% to 37.3%) and 42.9% (95% CI 38.0% to 47.7%) of the Han Chinese students who came to Lhasa by train and by air, respectively. Tibetan students had less changes in SaO2 (−2.95 percentage points, 95% CI −3.24% to −2.65%) and HR (10.89 beats per minute (bpm), 95% CI 9.62 to 12.16 bpm) from low to high altitude compared with Han Chinese students, although measurements did not differ between the two groups when measured at low altitude. Conclusions Healthy Tibetans are mostly protected against AMS and primarily maintain their good adaptation to high altitude, even after a long period of stay at low altitude.
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Affiliation(s)
- Gonggalanzi
- Tibet University Medical College, Tibet, China
| | - Labasangzhu
- Tibet University Medical College, Tibet, China
| | - Espen Bjertness
- Tibet University Medical College, Tibet, China.,Faculty of Medicine,University of Oslo, Oslo, Norway
| | - Tianyi Wu
- Tibet University Medical College, Tibet, China.,National Key Laboratory of High-Altitude Medicine, Xining, Qinghai, China
| | - Hein Stigum
- Faculty of Medicine,University of Oslo, Oslo, Norway.,Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Per Nafstad
- Faculty of Medicine,University of Oslo, Oslo, Norway.,Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
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MacInnis MJ, Koehle MS. Evidence for and Against Genetic Predispositions to Acute and Chronic Altitude Illnesses. High Alt Med Biol 2016; 17:281-293. [PMID: 27500591 DOI: 10.1089/ham.2016.0024] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
MacInnis, Martin J., and Michael S. Koehle. Evidence for and against genetic predispositions to acute and chronic altitude illnesses. High Alt Med Biol. 17:281-293, 2016.-Humans exhibit marked variation in their responses to hypoxia, with susceptibility to acute and chronic altitude illnesses being a prominent and medically important example. Many have hypothesized that genetic differences are the cause of these variable responses to hypoxia; however, until recently, these hypotheses were based primarily on small (and sometimes anecdotal) reports pertaining to apparent differences in altitude illness susceptibility between populations, the notion that a history of altitude illness is indicative of subsequent risk, the heritability of hypoxia-related traits, and candidate gene association studies. In the past 5 years, the use of genomic techniques has helped bolster the claim that susceptibility to some altitude illnesses is likely the result of genetic variation. For each of the major altitude illnesses, we summarize and evaluate the evidence stemming from three important characteristics of a genetic trait: (1) individual susceptibility and repeatability across assessments, (2) biogeographical differences and familial aggregation, and (3) association(s) with genetic variants. Evidence to support a genetic basis for susceptibilities to acute mountain sickness (AMS) and high-altitude cerebral edema (HACE) is limited, owing partially to the subjective and unclear phenotype of AMS and the rarity and severity of HACE. In contrast, recent genomic studies have identified genes that influence susceptibility to high-altitude pulmonary edema, chronic mountain sickness, and high-altitude pulmonary hypertension. The collection of more individual, familial, and biogeographical susceptibility data should improve our understanding of the extent to which genetic variation contributes to altitude illness susceptibility, and genomic and molecular investigations have the potential to elucidate the mechanisms that underpin altitude illness susceptibility.
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Affiliation(s)
| | - Michael S Koehle
- 2 School of Kinesiology, University of British Columbia , Vancouver, Canada .,3 Allan McGavin Sport Medicine Clinic, Department of Family Practice, University of British Columbia , Vancouver, Canada
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Gonggalanzi, Labasangzhu, Nafstad P, Stigum H, Wu T, Haldorsen ØD, Ommundsen K, Bjertness E. Acute mountain sickness among tourists visiting the high-altitude city of Lhasa at 3658 m above sea level: a cross-sectional study. ACTA ACUST UNITED AC 2016; 74:23. [PMID: 27252854 PMCID: PMC4888367 DOI: 10.1186/s13690-016-0134-z] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 04/17/2016] [Indexed: 02/01/2023]
Abstract
BACKGROUND Traveling to Tibet implies a risk for developing acute mountain sickness (AMS), and the size of this problem is likely increasing due to the rising number of tourists. No previous study on AMS has been conducted among the general tourist population in Tibet. Thus, the aim of this study was to estimate the prevalence and determinants of AMS in a large tourist population visiting Lhasa. METHODS A sample of 2385 tourists was recruited from seven randomly selected hotels in Lhasa between June and October 2010. Within three days of their first arrival, the participants filled in a questionnaire based on the Lake Louise Scoring System (LLSS) about AMS-related symptoms and potential contributing factors. AMS was defined as the presence of headache and a cumulative Lake Louise Score ≥4. After estimating the prevalence of AMS, a Log-Binomial Model was applied to analyse the relationship between AMS and selected risk factors. RESULTS The prevalence of AMS was 36.7 % (95 % CI: 34.6-38.7 %) and was not dependent on tourists' country of origin. Among the participants who developed AMS, 47.6 % reported that they experienced symptoms within the first 12 h after arriving in Lhasa, and 79.0 % reported that they had to reduce their activity level. A poor or average health condition (adjusted PR 1.63, 95 % CI 1.38-1.93), an age below 55 years (adjusted PR 1.29, 95 % CI 1.04-1.60), a rapid ascent to Lhasa (adjusted PR 1.17, 95 % CI 1.02-1.34) were independent AMS risk factors, while smoking (adjusted PR 0.75, 95 % CI 0.59-0.96) and pre-exposure to high altitude (adjusted PR 0.71, 95 % CI 0.60-0.84) reduced the risk of AMS. CONCLUSIONS AMS is commonly experienced by tourists visiting Lhasa Tibet, and often affects their activities. The tourists' country of origin did not seem to affect their risk of AMS, and their age was inversely related to AMS. Subjects planning to visit a high-altitude area should be prepared for experiencing AMS-related problems, and consider preventive measures such as pre-exposure or a gradual ascent to high altitudes.
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Affiliation(s)
- Gonggalanzi
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway ; Tibet University Medical College, No. 1 South Luobulinka Road, Lhasa, 850002 Tibet China
| | - Labasangzhu
- Tibet University Medical College, No. 1 South Luobulinka Road, Lhasa, 850002 Tibet China
| | - Per Nafstad
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway ; Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Hein Stigum
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway ; Division of Epidemiology, Norwegian Institute of Public Health, Oslo, Norway
| | - Tianyi Wu
- National Key Laboratory of High-Altitude Medicine, Qinghai, China
| | - Øyvind Drejer Haldorsen
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway
| | - Kristoffer Ommundsen
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway
| | - Espen Bjertness
- Institute of Health and Society, University of Oslo, P.O. Box 1130 Blindern, Oslo, 0318 Norway
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Vinnikov D, Brimkulov N, Krasotski V. Chronic Intermittent Hypoxia and Blood Pressure: Is There Risk for Hypertension in Healthy Individuals? High Alt Med Biol 2016; 17:5-10. [DOI: 10.1089/ham.2015.0067] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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Re-exposure to the hypobaric hypoxic brain injury of high altitude: plasma S100B levels and the possible effect of acclimatisation on blood-brain barrier dysfunction. Neurol Sci 2016; 37:533-9. [PMID: 26924650 PMCID: PMC4819780 DOI: 10.1007/s10072-016-2521-1] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2015] [Accepted: 02/15/2016] [Indexed: 10/31/2022]
Abstract
Hypobaric hypoxic brain injury results in elevated peripheral S100B levels which may relate to blood-brain barrier (BBB) dysfunction. A period of acclimatisation or dexamethasone prevents altitude-related illnesses and this may involve attenuation of BBB compromise. We hypothesised that both treatments would diminish the S100B response (a measure of BBB dysfunction) on re-ascent to the hypobaric hypoxia of high altitude, in comparison to an identical ascent completed 48 h earlier by the same group. Twelve healthy volunteers, six of which were prescribed dexamethasone, ascended Mt Fuji (summit 3700 m) and serial plasma S100B levels measured. The S100B values reduced from a baseline 0.183 µg/l (95 % CI 0.083-0.283) to 0.145 µg/l (95 % CI 0.088-0.202) at high altitude for the dexamethasone group (n = 6) and from 0.147 µg/l (95 % CI 0.022-0.272) to 0.133 µg/l (95 % CI 0.085-0.182) for the non-treated group (n = 6) [not statistically significant (p = 0.43 and p = 0.82) for the treated and non-treated groups respectively]. [These results contrasted with the statistically significant increase during the first ascent, S100B increasing from 0.108 µg/l (95 % CI 0.092-0.125) to 0.216 µg/l (95 % CI 0.165-0.267) at high altitude]. In conclusion, an increase in plasma S100B was not observed in the second ascent and this may relate to the effect of acclimatisation (or hypoxic pre-conditioning) on the BBB. An exercise stimulated elevation of plasma S100B levels was also not observed during the second ascent. The small sample size and wide confidence intervals, however, precludes any statistically significant conclusions and a larger study would be required to confirm these findings.
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Impact of Study Design on Reported Incidences of Acute Mountain Sickness: A Systematic Review. High Alt Med Biol 2015; 16:204-15. [DOI: 10.1089/ham.2015.0022] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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Development and preliminary test of a new plateau hyperbaric chamber. Am J Emerg Med 2015; 33:1497-500. [PMID: 26277732 DOI: 10.1016/j.ajem.2015.06.005] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2015] [Accepted: 06/03/2015] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE The objective of this study is to validate the performance, define its limits, and provide details on a new plateau hyperbaric chamber at 355-, 2880-, and 4532-m high altitude. METHODS A new multiplace plateau hyperbaric chamber was designed to satisfy the needed of patients who have acute mountain sickness. Tests were conducted inside the chamber at 355-, 2880-, and 4532-m high altitude. The safely and conveniences of the new plateau hyperbaric chamber were estimated. RESULTS Minimum pressures of the main compartment can reach up to 0.029, 0.022, and 0.02 MPa at 355-, 2880-, and 4532-m high altitude. During pressurization, there was no leak of air around the chamber. The time lag of pressure equilibration between main and buffer compartment varies from 30.3±2.01 to 200.5±5.44 seconds and between buffer compartment and ambient pressure varies from 60.2±4.13 to 215.9±6.76 seconds. CONCLUSIONS The chamber can be applicated for acute mountain sickness treatment safety and convenience. However, further experience about animals and human within the chamber is needed to improve the hardware and establish conditions of effective utilization of this equipment in the high altitude.
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Variants of the low oxygen sensors EGLN1 and HIF-1AN associated with acute mountain sickness. Int J Mol Sci 2014; 15:21777-87. [PMID: 25431923 PMCID: PMC4284677 DOI: 10.3390/ijms151221777] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/18/2014] [Revised: 11/17/2014] [Accepted: 11/18/2014] [Indexed: 02/06/2023] Open
Abstract
Two low oxygen sensors, Egl nine homolog 1 (EGLN1) and hypoxia-inducible factor 1-α inhibitor (HIF-1AN), play pivotal roles in the regulation of HIF-1α, and high altitude adaption may be involved in the pathology of acute mountain sickness (AMS). Here, we aimed to analyze single nucleotide polymorphisms (SNPs) in the untranslated regions of the EGLN1 and HIF-1AN genes and SNPs chosen from a genome-wide adaptation study of the Han Chinese population. To assess the association between EGLN1 and HIF-1AN SNPs and AMS in a Han Chinese population, a case-control study was performed including 190 patients and 190 controls. In total, thirteen SNPs were genotyped using the MassARRAY® MALDI-TOF system. Multiple genetic models were tested; The Akaike's information criterion (AIC) and Bayesian information criterion (BIC) values indicated that the dominant model may serve as the best-fit model for rs12406290 and rs2153364 of significant difference. However, these data were not significant after Bonferroni correction. No significant association was noted between AMS and rs12757362, rs1339894, rs1361384, rs2009873, rs2739513 or rs2486729 before and after Bonferroni correction. Further haplotype analyses indicated the presence of two blocks in EGLN1; one block consists of rs12406290-rs2153364, located upstream of the EGLN1 gene. Carriers of the "GG" haplotype of rs12406290-rs2153364 exhibited an increased risk of AMS after adjustments for age and smoking status. However, no significant association was observed among HIF-1AN 3'-untranslated region (3'-UTR) polymorphisms, haplotype and AMS. Our study indicates that variants in the EGLN1 5'-UTR influence the susceptibility to AMS in a Han Chinese population.
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Li Y, Liu Y. Oxygen enrichment and its application to life support systems for workers in high-altitude areas. INTERNATIONAL JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HEALTH 2014; 20:207-14. [PMID: 25000108 DOI: 10.1179/2049396714y.0000000068] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
BACKGROUND Workers coming from lowland regions are at risk of developing acute mountain sickness (AMS) when working in low oxygen high-altitude areas. OBJECTIVES The aim of this study was to improve the conditions that lead to hypoxia and ensure the safety of the high-altitude workers. We analyzed the influence of low atmospheric pressure on the oxygen enrichment process in high-altitude areas using an engineering method called low-pressure swing adsorption (LPSA). METHODS Fourteen male subjects were screened and divided into three groups by type of oxygen supply system used: (1) oxygen cylinder group; (2) LPSA oxygen dispersal group; and (3) control group. These tests included arterial oxygen saturation (SaO2), pulse rate (PR), breaths per minute (BPM), and blood pressure (BP). RESULTS The results showed that after supplying oxygen using the LPSA method at the tunnel face, the SaO2 of workers increased; the incidence of acute mountain sickness, PR, and BPM significantly decreased. CONCLUSIONS The LPSA life support system was found to be a simple, convenient, efficient, reliable, and applicable approach to ensure proper working conditions at construction sites in high-altitude areas.
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Subudhi AW, Bourdillon N, Bucher J, Davis C, Elliott JE, Eutermoster M, Evero O, Fan JL, Houten SJV, Julian CG, Kark J, Kark S, Kayser B, Kern JP, Kim SE, Lathan C, Laurie SS, Lovering AT, Paterson R, Polaner DM, Ryan BJ, Spira JL, Tsao JW, Wachsmuth NB, Roach RC. AltitudeOmics: the integrative physiology of human acclimatization to hypobaric hypoxia and its retention upon reascent. PLoS One 2014; 9:e92191. [PMID: 24658407 PMCID: PMC3962396 DOI: 10.1371/journal.pone.0092191] [Citation(s) in RCA: 59] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Accepted: 02/19/2014] [Indexed: 11/19/2022] Open
Abstract
An understanding of human responses to hypoxia is important for the health of millions of people worldwide who visit, live, or work in the hypoxic environment encountered at high altitudes. In spite of dozens of studies over the last 100 years, the basic mechanisms controlling acclimatization to hypoxia remain largely unknown. The AltitudeOmics project aimed to bridge this gap. Our goals were 1) to describe a phenotype for successful acclimatization and assess its retention and 2) use these findings as a foundation for companion mechanistic studies. Our approach was to characterize acclimatization by measuring changes in arterial oxygenation and hemoglobin concentration [Hb], acute mountain sickness (AMS), cognitive function, and exercise performance in 21 subjects as they acclimatized to 5260 m over 16 days. We then focused on the retention of acclimatization by having subjects reascend to 5260 m after either 7 (n = 14) or 21 (n = 7) days at 1525 m. At 16 days at 5260 m we observed: 1) increases in arterial oxygenation and [Hb] (compared to acute hypoxia: PaO2 rose 9±4 mmHg to 45±4 while PaCO2 dropped a further 6±3 mmHg to 21±3, and [Hb] rose 1.8±0.7 g/dL to 16±2 g/dL; 2) no AMS; 3) improved cognitive function; and 4) improved exercise performance by 8±8% (all changes p<0.01). Upon reascent, we observed retention of arterial oxygenation but not [Hb], protection from AMS, retention of exercise performance, less retention of cognitive function; and noted that some of these effects lasted for 21 days. Taken together, these findings reveal new information about retention of acclimatization, and can be used as a physiological foundation to explore the molecular mechanisms of acclimatization and its retention.
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Affiliation(s)
- Andrew W. Subudhi
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- Department of Biology, University of Colorado Colorado Springs, Colorado Springs, Colorado, United States of America
| | - Nicolas Bourdillon
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Jenna Bucher
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Christopher Davis
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jonathan E. Elliott
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Morgan Eutermoster
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Oghenero Evero
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jui-Lin Fan
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
- Lemanic Doctoral School of Neuroscience, University of Lausanne, Lausanne, Switzerland
| | - Sonja Jameson-Van Houten
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Colleen G. Julian
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Jonathan Kark
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Sherri Kark
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - Bengt Kayser
- Institute of Sports Sciences and Department of Physiology, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
| | - Julia P. Kern
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - See Eun Kim
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Corinna Lathan
- AnthroTronix, Inc., Silver Spring, Maryland, United States of America
| | - Steven S. Laurie
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Andrew T. Lovering
- Department of Human Physiology, University of Oregon, Eugene, Oregon, United States of America
| | - Ryan Paterson
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
| | - David M. Polaner
- Departments of Anesthesiology and Pediatrics, University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, Colorado, United States of America
| | - Benjamin J. Ryan
- Department of Integrative Physiology, University of Colorado Boulder, Boulder, Colorado, United States of America
| | - James L. Spira
- United States Department of Veterans Affairs, National Center for PTSD, Pacific Islands Health Care System, and Department of Psychiatry, University of Hawaii John A. Burns School of Medicine, Honolulu, Hawaii, United States of America
| | - Jack W. Tsao
- Wounded, Ill & Injured Directorate (M9), United States Navy Bureau of Medicine and Surgery, Falls Church, Virginia, United States of America
| | - Nadine B. Wachsmuth
- Department of Sports Medicine/Sports Physiology, University of Bayreuth, Bayreuth, Germany
| | - Robert C. Roach
- Altitude Research Center, Department of Emergency Medicine, University of Colorado Anschutz Medical Campus, Aurora, Colorado, United States of America
- * E-mail:
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Höhenkrankheit. Internist (Berl) 2014; 55:268-73. [DOI: 10.1007/s00108-013-3368-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
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Fan JL, Subudhi AW, Evero O, Bourdillon N, Kayser B, Lovering AT, Roach RC. AltitudeOmics: enhanced cerebrovascular reactivity and ventilatory response to CO2 with high-altitude acclimatization and reexposure. J Appl Physiol (1985) 2013; 116:911-8. [PMID: 24356520 DOI: 10.1152/japplphysiol.00704.2013] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The present study is the first to examine the effect of high-altitude acclimatization and reexposure on the responses of cerebral blood flow and ventilation to CO2. We also compared the steady-state estimates of these parameters during acclimatization with the modified rebreathing method. We assessed changes in steady-state responses of middle cerebral artery velocity (MCAv), cerebrovascular conductance index (CVCi), and ventilation (V(E)) to varied levels of CO2 in 21 lowlanders (9 women; 21 ± 1 years of age) at sea level (SL), during initial exposure to 5,260 m (ALT1), after 16 days of acclimatization (ALT16), and upon reexposure to altitude following either 7 (POST7) or 21 days (POST21) at low altitude (1,525 m). In the nonacclimatized state (ALT1), MCAv and V(E) responses to CO2 were elevated compared with those at SL (by 79 ± 75% and 14.8 ± 12.3 l/min, respectively; P = 0.004 and P = 0.011). Acclimatization at ALT16 further elevated both MCAv and Ve responses to CO2 compared with ALT1 (by 89 ± 70% and 48.3 ± 32.0 l/min, respectively; P < 0.001). The acclimatization gained for V(E) responses to CO2 at ALT16 was retained by 38% upon reexposure to altitude at POST7 (P = 0.004 vs. ALT1), whereas no retention was observed for the MCAv responses (P > 0.05). We found good agreement between steady-state and modified rebreathing estimates of MCAv and V(E) responses to CO2 across all three time points (P < 0.001, pooled data). Regardless of the method of assessment, altitude acclimatization elevates both the cerebrovascular and ventilatory responsiveness to CO2. Our data further demonstrate that this enhanced ventilatory CO2 response is partly retained after 7 days at low altitude.
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Affiliation(s)
- Jui-Lin Fan
- Institute of Sports Sciences, Faculty of Biology and Medicine, University of Lausanne, Lausanne, Switzerland
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Abstract
Among the several topics included in respiratory studies investigators have focused on the control of breathing for a relatively few number of years, perhaps only the last 75 to 80. For a very long time, the phenomenon of respiration presented a great mystery. The Chinese had suggestions for proper breathing, and later the Egyptians sought to understand its purpose. But in the western world, the early Greeks made the more significant observations. Centuries passed before the anatomical structures pertinent to respiration were properly visualized and located. There followed efforts to understand if lung movement was necessary for life and what happened in the lung. The rise of chemistry in the 18th century eventually clarified the roles of the gases significant in respiratory behavior. More time was needed to understand what gases provoked increases in breathing and where those gases worked. At this point, control of breathing became a significant focus of respiratory investigators. Studies included identifying the structures and functions of central and peripheral chemoreceptors, and airway receptors, sources of respiratory rhythm and pattern generation, the impact of the organism's status on its breathing including environment and disease/trauma. At this same time, mid- to late-20th century, efforts to mathematicize the variables in the control of breathing appeared. So though wonderment about the mysterious phenomenon of respiration began over two millennia ago, serious physiological investigation into its control is by comparison very young.
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Affiliation(s)
- Robert S Fitzgerald
- Departments of Environmental Health Sciences Division of Physiology, of Physiology, and of Medicine, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
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Song H, Ke T, Luo WJ, Chen JY. Non-high altitude methods for rapid screening of susceptibility to acute mountain sickness. BMC Public Health 2013; 13:902. [PMID: 24079477 PMCID: PMC3852617 DOI: 10.1186/1471-2458-13-902] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2012] [Accepted: 09/25/2013] [Indexed: 11/16/2022] Open
Abstract
Background Acute mountain sickness (AMS) refers to the cerebral abnormalities typically triggered by exposure to hypobaric hypoxia at high altitude. Although AMS is not often life threatening, it can seriously impact health quality and decrease productivity. Thus, detection of potential susceptibility to AMS has become important for people arriving at high-altitude plateaus for the first time, including laborers and military staff. The aim of this review was to examine techniques which efficiently assess the susceptibility to AMS prior to exposure to high altitude. Methods By searching online databases, we retrieved studies with associations between AMS and methods to detect the susceptible people who were not exposed to high altitudes. Studies reporting significant correlation coefficients between screening methods and AMS scores were included. Results Several screening techniques of AMS susceptibility were found including cold pressor test, heart rate variability, and lung functions. Of these markers, heart rate variability was positively associated with AMS scores, while the rest were negatively associated with AMS scores. Conclusions We identified three physiological markers that were significantly associated with the risk of AMS. Although it is well known that simple sea level tests are not really helpful in predicting AMS currently, these markers, to some degree, may be employed as references in predicting susceptibility.
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Affiliation(s)
- Han Song
- Department of Occupational and Environmental Health, School of Preventive Medicine, Fourth Military Medical University, No,169, Changlexi Road, Xi'an, Shaanxi 710032, China.
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Luo Y, Yang X, Gao Y. Strategies for the prevention of acute mountain sickness and treatment for large groups making a rapid ascent in China. Int J Cardiol 2013; 169:97-100. [PMID: 24095160 DOI: 10.1016/j.ijcard.2013.08.059] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2013] [Revised: 08/09/2013] [Accepted: 08/19/2013] [Indexed: 10/26/2022]
Abstract
Approximately 26.8% of China's land area has an elevation of 3000 m above sea level or higher. Because of recent demands for economic development and new construction in highland areas, many people have relocated from the plains to high plateau regions and have to face the possibility of contracting acute mountain sickness. Therefore, prevention and treatment strategies are necessary to reduce the incidence of acute mountain sickness in people who rapidly ascend to plateau areas. This paper describes the Chinese experience when large numbers of people moved to the plateau and the steps that were taken to deal with this illness. These steps included implementing basic prevention measures, increasing medical awareness among populations ascending to high altitudes, and installing standardized medical management systems to prevent and treat acute mountain sickness before, during, and after ascent. The incidence of acute mountain sickness can be reduced by improving prevention and treatment and by implementing the recommendations described in this manuscript.
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Affiliation(s)
- Yongjun Luo
- Department of Military Medical Geography, Third Military Medical University, Chongqing 400038, China; Key Laboratory of High Altitude Medicine (Ministry of Education), Third Military Medical University, Chongqing 400038, China; Key Laboratory of High Altitude Medicine (People's Liberation Army), Third Military Medical University, Chongqing 400038, China
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Kayser B, Dumont L, Lysakowski C, Combescure C, Haller G, Tramèr MR. Reappraisal of Acetazolamide for the Prevention of Acute Mountain Sickness: A Systematic Review and Meta-Analysis. High Alt Med Biol 2012; 13:82-92. [DOI: 10.1089/ham.2011.1084] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Affiliation(s)
- Bengt Kayser
- Institute of Movement Sciences and Sports Medicine, Medical Faculty, University of Geneva, Geneva, Switzerland
| | - Lionel Dumont
- Division of Anesthesiology, Geneva University Hospitals, Geneva, Switzerland
| | | | | | - Guy Haller
- Division of Anesthesiology, Geneva University Hospitals, Geneva, Switzerland
- Clinical Trial Unit, Geneva University Hospitals, Geneva, Switzerland
| | - Martin R. Tramèr
- Division of Anesthesiology, Geneva University Hospitals, Geneva, Switzerland
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Li X, Tao F, You H, Pei T, Gao Y. Factors associated with acute mountain sickness in young Chinese men on entering highland areas. Asia Pac J Public Health 2011; 27:NP116-31. [PMID: 22186404 DOI: 10.1177/1010539511427956] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
AIM The aim of this study was to explore the prediction factors for incidence of acute mountain sickness (AMS) in young males newly entering highland areas. METHODS A retrospective study of 4367 records of male highland soldiers from 2000 to 2005 was done. The factors were tested by logistic regression. RESULTS After selection by univariate model, ethnicity, altitude, season, deployment type, and prophylaxis were inserted into a multivariate model. The adjusted odds ratio (AOR) was 0.078 for Tibetan compared with Han. AORs for altitudes 3600 to 3700, 4000 to 4300, and 4600 to 4700 m versus 2900 to 3100 m were 4.490, 4.532, and 4.964, respectively. AOR for cold season versus warm season was 1.332. AORs for emergency land deployment and air deployment versus normal land deployment were 2.261 and 1.614, respectively. The AOR was 0.741 for prophylaxis versus none. The area under receiver operating characteristic curve was 0.731 (optimal cutoff = 0.370). CONCLUSIONS Adjusting for altitude, risk factors that contributed to AMS were being non-Tibetan, cold season, greater speed of transport, emergency conditions, and without prophylaxis. The model established is acceptable for assisting AMS prediction.
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Affiliation(s)
- Xiaoxiao Li
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, Shapingba District, Chongqing, P. R. China Key Laboratory of High Altitude Medicine, Ministry of Education, Third Military Medical University, Shapingba District, Chongqing, P. R. China The Key Laboratory of High Altitude Medicine, PLA, Chongqing, P. R. China
| | - Fasheng Tao
- Urumqi General Hospital of Lanzhou Military District, Urumqi, Xinjiang, P. R. China
| | - Haiyan You
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, Shapingba District, Chongqing, P. R. China Key Laboratory of High Altitude Medicine, Ministry of Education, Third Military Medical University, Shapingba District, Chongqing, P. R. China The Key Laboratory of High Altitude Medicine, PLA, Chongqing, P. R. China
| | - Tao Pei
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, Shapingba District, Chongqing, P. R. China Key Laboratory of High Altitude Medicine, Ministry of Education, Third Military Medical University, Shapingba District, Chongqing, P. R. China The Key Laboratory of High Altitude Medicine, PLA, Chongqing, P. R. China
| | - Yuqi Gao
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, Shapingba District, Chongqing, P. R. China Key Laboratory of High Altitude Medicine, Ministry of Education, Third Military Medical University, Shapingba District, Chongqing, P. R. China The Key Laboratory of High Altitude Medicine, PLA, Chongqing, P. R. China
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Li X, Tao F, Pei T, You H, Liu Y, Gao Y. Population level determinants of acute mountain sickness among young men: a retrospective study. BMC Public Health 2011; 11:740. [PMID: 21955882 PMCID: PMC3190355 DOI: 10.1186/1471-2458-11-740] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/28/2011] [Accepted: 09/28/2011] [Indexed: 11/29/2022] Open
Abstract
Background Many visitors, including military troops, who enter highland regions from low altitude areas may suffer from acute mountain sickness (AMS), which negatively impacts workable man-hours and increases healthcare costs. The aim of this study was to evaluate the population level risk factors and build a multivariate model, which might be applicable to reduce the effects of AMS on Chinese young men traveling to this region. Methods Chinese highland military medical records were used to obtain data of young men (n = 3727) who entered the Tibet plateau between the years of 2006-2009. The relationship between AMS and travel profile, demographic characteristics, and health behaviors were evaluated by logistic regression. Univariate logistic models estimated the crude odds ratio. The variables that showed significance in the univariate model were included in a multivariate model to derive adjusted odds ratios and build the final model. Data corresponding to odd and even years (2 subsets) were analyzed separately and used in a simple cross-validation. Results Univariate analysis indicated that travel profile, prophylactic use, ethnicity, and province of birth were all associated with AMS in both subsets. In multivariate analysis, young men who traveled from lower altitude (600-800 m vs. 1300-1500 m, adjusted odds ratio (AOR) = 1.32-1.44) to higher altitudes (4100-4300 m vs. 2900-3100 m, AOR = 3.94-4.12; 3600-3700 m vs. 2900-3100 m, AOR = 2.71-2.74) by air or rapid land transport for emergency mission deployment (emergency land deployment vs. normal land deployment, AOR = 2.08-2.11; normal air deployment vs. normal land deployment, AOR = 2.00-2.20; emergency air deployment vs. normal land deployment, AOR = 2.40-3.34) during the cold season (cold vs. warm, AOR = 1.25-1.28) are at great risk for developing AMS. Non-Tibetan male soldiers (Tibetan vs. Han, AOR = 0.03-0.08), born and raised in lower provinces (eastern vs. northwestern, AOR = 1.32-1.39), and deployed without prophylaxis (prophylactic drug vs. none, AOR = 0.75-0.76), also represented a population at significantly increased risk for AMS. The predicted model was built; the area under receiver operating characteristic curve was 0.703. Conclusion Before a group of young men first enter a high altitude area, it is important that a health service plan should be made referring to the group's travel profile and with respect to young men's ethnicity and province of birth. Low-cost Chinese traditional prophylactic drugs might have some effect on decreasing the risk of AMS, although this needs further verification.
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Affiliation(s)
- Xiaoxiao Li
- Department of Health Service, College of High Altitude Military Medicine, Third Military Medical University, 30 Gaotanyan Street, Shapingba District, Chongqing, China
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Vearrier D, Greenberg MI. Occupational health of miners at altitude: adverse health effects, toxic exposures, pre-placement screening, acclimatization, and worker surveillance. Clin Toxicol (Phila) 2011; 49:629-40. [PMID: 21861588 DOI: 10.3109/15563650.2011.607169] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
CONTEXT Mining operations conducted at high altitudes provide health challenges for workers as well as for medical personnel. OBJECTIVE To review the literature regarding adverse health effects and toxic exposures that may be associated with mining operations conducted at altitude and to discuss pre-placement screening, acclimatization issues, and on-site surveillance strategies. METHODS We used the Ovid ( http://ovidsp.tx.ovid.com ) search engine to conduct a MEDLINE search for "coal mining" or "mining" and "altitude sickness" or "altitude" and a second MEDLINE search for "occupational diseases" and "altitude sickness" or "altitude." The search identified 97 articles of which 76 were relevant. In addition, the references of these 76 articles were manually reviewed for relevant articles. CARDIOVASCULAR EFFECTS: High altitude is associated with increased sympathetic tone that may result in elevated blood pressure, particularly in workers with pre-existing hypertension. Workers with a history of coronary artery disease experience ischemia at lower work rates at high altitude, while those with a history of congestive heart failure have decreased exercise tolerance at high altitude as compared to healthy controls and are at higher risk of suffering an exacerbation of their heart failure. PULMONARY EFFECTS: High altitude is associated with various adverse pulmonary effects, including high-altitude pulmonary edema, pulmonary hypertension, subacute mountain sickness, and chronic mountain sickness. Mining at altitude has been reported to accelerate silicosis and other pneumoconioses. Miners with pre-existing pneumoconioses may experience an exacerbation of their condition at altitude. Persons traveling to high altitude have a higher incidence of Cheyne-Stokes respiration while sleeping than do persons native to high altitude. Obesity increases the risk of pulmonary hypertension, acute mountain sickness, and sleep-disordered breathing. NEUROLOGICAL EFFECTS: The most common adverse neurological effect of high altitude is acute mountain sickness, while the most severe adverse neurological effect is high-altitude cerebral edema. Poor sleep quality and sleep-disordered breathing may contribute to daytime sleepiness and impaired cognitive performance that could potentially result in workplace injuries, particularly in miners who are already at increased risk of suffering unintentional workplace injuries. OPHTHALMOLOGICAL EFFECTS: Adverse ophthalmological effects include increased exposure to ultraviolet light and xerophthalmia, which may be further exacerbated by occupational dust exposure. RENAL EFFECTS: High altitude is associated with a protective effect in patients with renal disease, although it is unknown how this would affect miners with a history of chronic renal disease from exposure to silica and other renal toxicants. HEMATOLOGICAL EFFECTS: Advanced age increases the risk of erythrocytosis and chronic mountain sickness in miners. Thrombotic and thromboembolic events are also more common at high altitude. MUSCULOSKELETAL EFFECTS: Miners are at increased risk for low back pain due to occupational factors, and the easy fatigue at altitude has been reported to further predispose workers to this disorder. TOXIC EXPOSURES: Diesel emissions at altitude contain more carbon monoxide due to increased incomplete combustion of fuel. In addition, a given partial pressure of carbon monoxide at altitude will result in a larger percentage of carboxyhemoglobin at altitude. Miners with a diagnosis of chronic obstructive pulmonary disease may be at higher risk for morbidity from exposure to diesel exhaust at altitude. CONCLUSIONS Both mining and work at altitude have independently been associated with a number of adverse health effects, although the combined effect of mining activities and high altitude has not been adequately studied. Careful selection of workers, appropriate acclimatization, and limited on-site surveillance can help control most health risks. Further research is necessary to more completely understand the risks of mining at altitude and delineate what characteristics of potential employees put them at risk for altitude-related morbidity or mortality.
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Affiliation(s)
- David Vearrier
- Department of Emergency Medicine, Drexel University College of Medicine, Philadelphia, PA 19102, USA
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Anderson PJ, Miller AD, O'Malley KA, Ceridon ML, Beck KC, Wood CM, Wiste HJ, Mueller JJ, Johnson JB, Johnson BD. Incidence and Symptoms of High Altitude Illness in South Pole Workers: Antarctic Study of Altitude Physiology (ASAP). CLINICAL MEDICINE INSIGHTS-CIRCULATORY RESPIRATORY AND PULMONARY MEDICINE 2011; 5:27-35. [PMID: 21695160 PMCID: PMC3114308 DOI: 10.4137/ccrpm.s6882] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Introduction: Each year, the US Antarctic Program rapidly transports scientists and support personnel from sea level (SL) to the South Pole (SP, 2835 m) providing a unique natural laboratory to quantify the incidence of acute mountain sickness (AMS), patterns of altitude related symptoms and the field effectiveness of acetazolamide in a highly controlled setting. We hypothesized that the combination of rapid ascent (3 hr), accentuated hypobarism (relative to altitude), cold, and immediate exertion would increase altitude illness risk. Methods: Medically screened adults (N = 246, age = 37 ± 11 yr, 30% female, BMI = 26 ± 4 kg/m2) were recruited. All underwent SL and SP physiological evaluation, completed Lake Louise symptom questionnaires (LLSQ, to define AMS), and answered additional symptom related questions (eg, exertional dyspnea, mental status, cough, edema and general health), during the 1st week at altitude. Acetazolamide, while not mandatory, was used by 40% of participants. Results: At SP, the barometric pressure resulted in physiological altitudes that approached 3400 m, while T °C averaged −42, humidity 0.03%. Arterial oxygen saturation averaged 89% ± 3%. Overall, 52% developed LLSQ defined AMS. The most common symptoms reported were exertional dyspnea-(87%), sleeping difficulty-(74%), headache-(66%), fatigue-(65%), and dizziness/lightheadedness-(46%). Symptom severity peaked on days 1–2, yet in >20% exertional dyspnea, fatigue and sleep problems persisted through day 7. AMS incidence was similar between those using acetazolamide and those abstaining (51 vs. 52%, P = 0.87). Those who used acetazolamide tended to be older, have less altitude experience, worse symptoms on previous exposures, and less SP experience. Conclusion: The incidence of AMS at SP tended to be higher than previously reports in other geographic locations at similar altitudes. Thus, the SP constitutes a more intense altitude exposure than might be expected considering physical altitude alone. Many symptoms persist, possibly due to extremely cold, arid conditions and the benefits of acetazolamide appeared negligible, though it may have prevented more severe symptoms in higher risk subjects.
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Affiliation(s)
- Paul J Anderson
- Health Partners Occupational and Environmental Medicine Residency, St. Paul, MN, USA
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MacInnis MJ, Koehle MS, Rupert JL. Evidence for a genetic basis for altitude illness: 2010 update. High Alt Med Biol 2011; 11:349-68. [PMID: 21190504 DOI: 10.1089/ham.2010.1030] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Altitude illness refers to a group of environmentally mediated pathophysiologies. Many people will suffer acute mountain sickness shortly after rapidly ascending to a moderately hypoxic environment, and an unfortunate few will develop potentially fatal conditions such as high altitude pulmonary edema or high altitude cerebral edema. Some individuals seem to be predisposed to developing altitude illness, suggesting an innate contribution to susceptibility. The implication that there are altitude-sensitive and altitude-tolerant individuals has stimulated much research into the contribution of a genetic background to the efficacy of altitude acclimatization. Although the effect of altitude attained and rate of ascent on the etiology of altitude illness is well known, there are only tantalizing, but rapidly accumulating, clues to the genes that may be involved. In 2006, we reviewed what was then known about the genetics of altitude illness. This article updates that review and attempts to tabulate all the available genetic data pertaining to these conditions. To date, 58 genes have been investigated for a role in altitude illness. Of these, 17 have shown some association with the susceptibility to, or the severity of, these conditions, although in many cases the effect size is small or variable. Caution is recommended when evaluating the genes for which no association was detected, because a number of the investigations reviewed in this article were insufficiently powered to detect small effects. No study has demonstrated a clear-cut altitude illness gene, but the accumulating data are consistent with a polygenic condition with a strong environmental component. The genes that have shown an association affect a variety of biological pathways, suggesting that either multiple systems are involved in altitude pathophysiology or that gene-gene interactions play a role. Although numerous studies have been performed to investigate specific genes, few have looked for evidence of heritability or familial transmission, or for epidemiological patterns that would be consistent with genetically influenced conditions. Future trends, such as genome-wide association studies and epigenetic analysis, should lead to enhanced understanding of the complex interactions within the genome and between the genome and hypoxic environments that contribute to an individual's capacity to acclimatize rapidly and effectively to altitude.
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Affiliation(s)
- Martin J MacInnis
- School of Human Kinetics, University of British Columbia, 6081 University Boulevard, Vancouver, BC, Canada
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Lippl FJ, Neubauer S, Schipfer S, Lichter N, Tufman A, Otto B, Fischer R. Hypobaric hypoxia causes body weight reduction in obese subjects. Obesity (Silver Spring) 2010; 18:675-81. [PMID: 20134417 DOI: 10.1038/oby.2009.509] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The reason for weight loss at high altitudes is largely unknown. To date, studies have been unable to differentiate between weight loss due to hypobaric hypoxia and that related to increased physical exercise. The aim of our study was to examine the effect of hypobaric hypoxia on body weight at high altitude in obese subjects. We investigated 20 male obese subjects (age 55.7 +/- 4.1 years, BMI 33.7 +/- 1.0 kg/m(2)). Body weight, waist circumference, basal metabolic rate (BMR), nutrition protocols, and objective activity parameters as well as metabolic and cardiovascular parameters, blood gas analysis, leptin, and ghrelin were determined at low altitude (LA) (Munich 530 m, D1), at the beginning and at the end of a 1-week stay at high altitude (2,650 m, D7 and D14) and 4 weeks after returning to LA (D42). Although daily pace counting remained stable at high altitude, at D14 and D42, participants weighed significantly less and had higher BMRs than at D1. Food intake was decreased at D7. Basal leptin levels increased significantly at high altitude despite the reduction in body weight. Diastolic blood pressure was significantly lower at D7, D14, and D42 compared to D1. This study shows that obese subjects lose weight at high altitudes. This may be due to a higher metabolic rate and reduced food intake. Interestingly, leptin levels rise in high altitude despite reduced body weight. Hypobaric hypoxia seems to play a major role, although the physiological mechanisms remain unclear. Weight loss at high altitudes was associated with clinically relevant improvements in diastolic blood pressure.
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Affiliation(s)
- Florian J Lippl
- Division of Gastroenterology, Department of Internal Medicine, University Hospital of Ludwig-Maximilians-University, Munich, Germany.
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