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Yu Y, Gao P, Xie L, Wang K, Dou D, Gong Q. Is Smoking Associated with the Risk of Acute Mountain Sickness? A Systematic Review and Meta-Analysis. High Alt Med Biol 2024; 25:226-237. [PMID: 38847053 DOI: 10.1089/ham.2022.0037] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/05/2024] Open
Abstract
Background: Controversy remains in the association between smoking and the risk of acute mountain sickness (AMS). Therefore, a systematic review of the existing literature may help clarify this association. Methods: We conducted a systematic search of PubMed, Embase, and Cochrane Library from database inception up to October 19, 2021. Both unadjusted and adjusted relative risks (RRs) and 95% confidence intervals (CIs) were calculated to compare the risk of AMS in the smoking and nonsmoking groups. Meta-regression was conducted to explore the factors causing heterogeneity of the studies, and subsequent stratified analysis was performed to present the pooled RR in different subgroups. Publication bias was assessed using funnel plots. Results: A total of 28 eligible articles (31 studies) were included. The pooled unadjusted and adjusted RRs were 0.88 (95% CI: 0.78-1.01) and 0.87 (95% CI: 0.77-0.99), respectively, using random-effect models. Publication bias was observed owing to restrictions on the sample size. The ascending altitude and sex composition of the study population were likely sources of heterogeneity according to meta-regression. Studies on participants with an ascending altitude of over 3,500 m or composed of both males and females reported a slight but not significant protective effect of smoking on the risk of AMS, with high heterogeneity. Conclusions: Smoking had no significant effect on AMS risk in this meta-analysis. Current studies showed high heterogeneity and included little information on quantitative exposure to smoking (i.e., dose and frequency); thus, the results require careful explanation.
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Affiliation(s)
- Yuelin Yu
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Peng Gao
- Department of Epidemiology and Biostatistics, School of Public Health, Peking University, Beijing, China
| | - Lianke Xie
- State Grid Shandong Electric Power Company, Electric Power Research Institute, Jinan, China
| | - Kun Wang
- State Grid Shandong Electric Power Company, Electric Power Research Institute, Jinan, China
| | - Dandan Dou
- State Grid Shandong Electric Power Company, Electric Power Research Institute, Jinan, China
| | - Quanquan Gong
- State Grid Shandong Electric Power Company, Electric Power Research Institute, Jinan, China
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Modenini G, Abondio P, Sazzini M, Boattini A. Polymorphic transposable elements provide new insights on high-altitude adaptation in the Tibetan Plateau. Genomics 2024; 116:110854. [PMID: 38701989 DOI: 10.1016/j.ygeno.2024.110854] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2024] [Revised: 03/23/2024] [Accepted: 04/30/2024] [Indexed: 05/06/2024]
Abstract
Several studies demonstrated that populations living in the Tibetan plateau are genetically and physiologically adapted to high-altitude conditions, showing genomic signatures ascribable to the action of natural selection. However, so far most of them relied solely on inferences drawn from the analysis of coding variants and point mutations. To fill this gap, we focused on the possible role of polymorphic transposable elements in influencing the adaptation of Tibetan and Sherpa highlanders. To do so, we compared high-altitude and middle/low-lander individuals of East Asian ancestry by performing in silico analyses and differentiation tests on 118 modern and ancient samples. We detected several transposable elements associated with high altitude, which map genes involved in cardiovascular, hematological, chem-dependent and respiratory conditions, suggesting that metabolic and signaling pathways taking part in these functions are disproportionately impacted by the effect of environmental stressors in high-altitude individuals. To our knowledge, our study is the first hinting to a possible role of transposable elements in the adaptation of Tibetan and Sherpa highlanders.
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Affiliation(s)
- Giorgia Modenini
- Dept. of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy.
| | - Paolo Abondio
- IRCCS Istituto Delle Scienze Neurologiche Di Bologna, Bologna, Italy
| | - Marco Sazzini
- Dept. of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy; Interdepartmental Centre - Alma Mater Research Institute on Global Changes and Climate Change, University of Bologna, Italy
| | - Alessio Boattini
- Dept. of Biological, Geological and Environmental Sciences, University of Bologna, Bologna, Italy
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Wu Y, Zhang C, Chen Y, Luo YJ. Association between acute mountain sickness (AMS) and age: a meta-analysis. Mil Med Res 2018; 5:14. [PMID: 29747689 PMCID: PMC5946480 DOI: 10.1186/s40779-018-0161-x] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/30/2017] [Accepted: 04/24/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Acute mountain sickness (AMS) is a potentially lethal condition caused by acute hypoxia after ascending to altitudes higher than 2500 m in a short time. The main symptom of AMS is headache. Numerous risk factors of AMS have been examined, including gender, obesity, ascent rate, age and individual susceptibility. In previous studies, age was considered a predisposing factor for AMS. However, different opinions have been raised in recent years. To clarify the association between AMS and age, we conducted this meta-analysis. METHODS We obtained observational studies that explored risk factors for AMS by searching PubMed, Embase, China National Knowledge Internet (CNKI), the Wanfang database and CQVIP for articles published before March 2017. The studies included were required to provide the mean age and its standard deviation for subjects with and without AMS, the maximum altitude attained and the mode of ascent. The Lake Louse Score (LLS) or the Chinese AMS score (CAS) was used to judge the severity of AMS symptoms and incidence. Studies were pooled for the analysis by using a random effects model in RevMan 5.0. Meta-regression and subgroup analyses were conducted to identify sources of heterogeneity using Stata 14.2 and RevMan 5.0. RESULTS In total, 17 studies were included, and the overall number of subjects with and without AMS was 1810 and 3014, respectively. The age ranged from 10 to 76 years. Analysis of the 17 included studies showed that age was not associated with AMS (mean difference (MD) = 0.10; 95% CI: -0.38-0.58; P = 0.69). CONCLUSION This meta-analysis suggests that there is no association between age and the risk of AMS. Race, age, and ascent mode are common sources of heterogeneity, which may provide an analytical orientation for future heterogeneity analyses.
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Affiliation(s)
- Yu Wu
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Battalion 5 of Cadet Brigade, Army Medical University, Chongqing, 400038, China
| | - Chi Zhang
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China
| | - Yu Chen
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China.,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China
| | - Yong-Jun Luo
- Department of Military Medical Geography, Army Medical Service Training Base, Army Medical University, Chongqing, 400038, China. .,Key Laboratory of High Altitude Environmental Medicine of PLA, Army Medical University, Chongqing, 400038, China.
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Relationship between Smoking and Acute Mountain Sickness: A Meta-Analysis of Observational Studies. BIOMED RESEARCH INTERNATIONAL 2017; 2017:1409656. [PMID: 29259975 PMCID: PMC5702408 DOI: 10.1155/2017/1409656] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/04/2016] [Revised: 03/12/2017] [Accepted: 06/06/2017] [Indexed: 12/27/2022]
Abstract
Aims Previous epidemiological investigations of the relationship between smoking and acute mountain sickness (AMS) risk yielded inconsistent findings. Therefore, a meta-analysis of observational studies was performed to determine whether smoking is related to the development of AMS. Methods Searches were performed on PubMed, Scopus, Embase, and Web of Science for relevant studies that were published before November 2016 reporting smoking prevalence and AMS. Two evaluators independently selected studies, extracted data, and assessed study quality. The pooled relative risks (RRs) and 95% confidence intervals (CIs) were obtained using random-effects models. Subgroup analyses were performed according to the type of participant, altitude, and study design. Results A total of 11 observational studies involving 7,106 participants, 2,408 of which had AMS, were eligible for inclusion in this meta-analysis. The summary RR for AMS comparing smokers to nonsmokers was 1.02 (95% CI: 0.83 to 1.26). Specific analyses for altitude, type of participant, and study design yielded similar results. There was significant heterogeneity for all studies (Q = 37.43; P < 0.001; I2 = 73%, 95% CI: 51% to 85%). No publication bias was observed (Egger's test: P = 0.548, Begg's test: P = 0.418). Conclusions The meta-analysis indicates that no difference was found in AMS risk with regard to smoking status.
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Sánchez-Mascuñano A, Masuet-Aumatell C, Morchón-Ramos S, Ramon JM. Relationship of altitude mountain sickness and smoking: a Catalan traveller's cohort study. BMJ Open 2017; 7:e017058. [PMID: 28947454 PMCID: PMC5623483 DOI: 10.1136/bmjopen-2017-017058] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVES The aim of this study is to analyse the relationship between smoking and altitude mountain sickness in a cohort of travellers to 2500 metres above sea level (masl) or higher. SETTING Travel Health Clinic at the Hospital Universitari de Bellvitge, in Barcelona, Spain. PARTICIPANTS A total of 302 adults seeking medical advice at the travel clinic, between July 2012 and August 2014, before travelling to 2500 masl or above, who agreed to participate in the study and to be contacted after the trip were included. Individuals who met the following criteria were excluded: younger than 18 years old, taking carbonic anhydrase inhibitors for chronic use, undergoing treatment with systemic corticosteroids and taking any medication that might prevent or treat altitude mountain sickness (AMS) prior to or during the trip. The majority of participants were women (n=156, 51.7%). The mean age was 37.7 years (SD 12.3). The studied cohort included 74 smokers (24.5%), 158 (52.3%) non-smokers and 70 (23.2%) ex-smokers. No statistical differences were observed between different sociodemographic characteristics, constitutional symptoms or drug use and smoking status. OUTCOMES The main outcome was the development of AMS, which was defined according to the Lake Louise AMS criteria. RESULTS AMS, according to the Lake Louise score, was significantly lower in smokers; the value was 14.9%, 95% CI (6.8 to 23.0%) in smokers and 29.4%, 95% CI (23.5 to 35.3%) in non-smokers with an adjusted OR of 0.54, 95% CI (0.31 to 0.97) independent of gender, age and maximum altitude reached. CONCLUSIONS These results suggest that smoking could reduce the risk of AMS in non-acclimated individuals. Further studies should be performed in larger cohorts of travellers to confirm these results. Despite the results, smoking must be strongly discouraged because it greatly increases the risk of cardiorespiratory diseases, cancer and other diseases.
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Affiliation(s)
- Alba Sánchez-Mascuñano
- Department of Preventive Medicine, Bellvitge Biomedical Research Institute (IDIBELL), International Health Center and Travel Medicine Clinic, University Hospital of Bellvitge, L’Hospitalet de Llobregat, Catalonia, Spain
| | - Cristina Masuet-Aumatell
- Department of Preventive Medicine, Bellvitge Biomedical Research Institute (IDIBELL), International Health Center and Travel Medicine Clinic, University Hospital of Bellvitge, L’Hospitalet de Llobregat, Catalonia, Spain
| | - Sergio Morchón-Ramos
- Department of Preventive Medicine, Bellvitge Biomedical Research Institute (IDIBELL), International Health Center and Travel Medicine Clinic, University Hospital of Bellvitge, L’Hospitalet de Llobregat, Catalonia, Spain
| | - Josep M Ramon
- Department of Preventive Medicine, Bellvitge Biomedical Research Institute (IDIBELL), International Health Center and Travel Medicine Clinic, University Hospital of Bellvitge, L’Hospitalet de Llobregat, Catalonia, Spain
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San Martin R, Brito J, Siques P, León-Velarde F. Obesity as a Conditioning Factor for High-Altitude Diseases. Obes Facts 2017; 10:363-372. [PMID: 28810235 PMCID: PMC5644942 DOI: 10.1159/000477461] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 05/10/2017] [Indexed: 12/19/2022] Open
Abstract
Obesity, a worldwide epidemic, has become a major health burden because it is usually accompanied by an increased risk for insulin resistance, diabetes, hypertension, cardiovascular diseases, and even some kinds of cancer. It also results in associated increases in healthcare expenditures and labor and economic consequences. There are also other fields of medicine and biology where obesity or being overweight play a major role, such as high-altitude illnesses (acute mountain sickness, hypoxic pulmonary hypertension, and chronic mountain sickness), where an increasing relationship among these two morbid statuses has been demonstrated. This association could be rooted in the interactions between obesity-related metabolic alterations and critical ventilation impairments due to obesity, which would aggravate hypobaric hypoxia at high altitudes, leading to hypoxemia, which is a trigger for developing high-altitude diseases. This review examines the current literature to support the idea that obesity or overweight could be major conditioning factors at high altitude.
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Affiliation(s)
- Rocío San Martin
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Julio Brito
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
- *Julio Brito, Institute of Health Studies, Universidad Arturo Prat, Avda. Arturo Prat 2120, Iquique, 1110939, Chile,
| | - Patricia Siques
- Institute of Health Studies, Universidad Arturo Prat, Iquique, Chile
| | - Fabiola León-Velarde
- Department of Biological and Physiological Sciences. Facultad de Ciencias y Filosofía/ IIA, Universidad Peruana Cayetano Heredia, Lima, Perú
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Xu C, Lu HX, Wang YX, Chen Y, Yang SH, Luo YJ. Association between smoking and the risk of acute mountain sickness: a meta-analysis of observational studies. Mil Med Res 2016; 3:37. [PMID: 27980800 PMCID: PMC5146861 DOI: 10.1186/s40779-016-0108-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/28/2016] [Accepted: 11/26/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND People rapidly ascending to high altitudes (>2500 m) may suffer from acute mountain sickness (AMS). The association between smoking and AMS risk remains unclear. Therefore, we performed a meta-analysis to evaluate the association between smoking and AMS risk. METHODS The association between smoking and AMS risk was determined according to predefined criteria established by our team. Meta-analysis was conducted according to the PRISMA guidelines. We included all relevant studies listed in the PubMed and Embase databases as of September 2015 in this meta-analysis and performed systemic searches using the terms "smoking", "acute mountain sickness" and "risk factor". The included studies were required to provide clear explanations regarding their definitions of smoking, the final altitudes reached by their participants and the diagnostic criteria used to diagnose AMS. Odds ratios (ORs) were used to evaluate the association between smoking and AMS risk across the studies, and the Q statistic was used to test OR heterogeneity, which was considered significant when P < 0.05. We also computed 95% confidence intervals (CIs). Data extracted from the articles were analyzed with Review Manager 5.3 (Cochrane Collaboration, Oxford, UK). RESULTS We used seven case-control studies including 694 smoking patients and 1986 non-smoking controls to analyze the association between smoking and AMS risk. We observed a significant association between AMS and smoking (OR = 0.71, 95% CI 0.52-0.96, P = 0.03). CONCLUSIONS We determined that smoking may protect against AMS development. However, we do not advise smoking to prevent AMS. More studies are necessary to confirm the role of smoking in AMS risk.
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Affiliation(s)
- Chen Xu
- Department of Military Medical Geography, Third Military Medical University, Chongqing, 400038 China ; Battalion 5 of Cadet Brigade, Third Military Medical University, Chongqing, 400038 China ; Key Laboratory of High Altitude Environmental Medicine (Ministry of Education), Third Military Medical University, Chongqing, 400038 China
| | - Hong-Xiang Lu
- Department of Military Medical Geography, Third Military Medical University, Chongqing, 400038 China ; Key Laboratory of High Altitude Environmental Medicine (Ministry of Education), Third Military Medical University, Chongqing, 400038 China
| | - Yu-Xiao Wang
- Department of Military Medical Geography, Third Military Medical University, Chongqing, 400038 China ; Key Laboratory of High Altitude Environmental Medicine (Ministry of Education), Third Military Medical University, Chongqing, 400038 China
| | - Yu Chen
- Department of Military Medical Geography, Third Military Medical University, Chongqing, 400038 China ; Key Laboratory of High Altitude Environmental Medicine (Ministry of Education), Third Military Medical University, Chongqing, 400038 China
| | - Sheng-Hong Yang
- Mountain Sickness Research Institute, 18th Hospital of PLA, Yecheng, Xinjiang 844900 China
| | - Yong-Jun Luo
- Department of Military Medical Geography, Third Military Medical University, Chongqing, 400038 China ; Key Laboratory of High Altitude Environmental Medicine (Ministry of Education), Third Military Medical University, Chongqing, 400038 China
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Vinnikov D, Blanc PD, Steinmaus C. Is Smoking a Predictor for Acute Mountain Sickness? Findings From a Meta-Analysis. Nicotine Tob Res 2015; 18:1509-16. [PMID: 26419295 DOI: 10.1093/ntr/ntv218] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/26/2015] [Accepted: 09/12/2015] [Indexed: 11/13/2022]
Abstract
AIM Studies of the potential association between cigarette smoking and acute mountain sickness (AMS) have reached contradictory conclusions. Our aim was to perform a meta-analysis of studies across a range of populations to ascertain better the true relationship between cigarette smoking and AMS. MATERIALS AND METHODS We used the PRISMA protocol to identify and screen eligible studies of smoking and AMS. Databases including Pubmed and Google Scholar were searched, using the terms "smoking" and "acute mountain sickness." We conducted a meta-analysis of the selected studies in order to evaluate causal inference, evaluate potential biases, and investigate possible sources of heterogeneity across studies. RESULTS We identified 3907 publications, of which 29 were eligible for inclusion by reporting smoking status and AMS. Of these, eight publications were excluded because they were duplicative or were lacking quantitative data. The 21 studies analyzed included 16 566 subjects. These fell into two groups: occupational/military (n = 8) or volunteers/trekkers/mixed (n = 13). Study heterogeneity was high (X (2) = 55.5, P < .001). Smoking was not statistically associated with increased risk of AMS: pooled OR = 0.88 (95% CI = 0.74-1.05). Stratification yielded similar risk estimates among the occupational/military studies versus all others and studies at relatively higher and lower altitudes. CONCLUSIONS Overall, smoking was not statistically significantly associated with AMS: there is no consistent effect of cigarette smoking acting as either a protective factor against or a risk factor for AMS. IMPLICATIONS This is the first quantitative assessment of published studies on smoking and AMS, which shows smoking to be neither a risk, nor protective. Studies specifically focusing on smoking as a risk factor, should guide further research on this issue. Although all smokers should be strongly advised to quit, studies on risk factors for AMS focusing on other exposures could shed light on the full range of risks for AMS.
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Affiliation(s)
- Denis Vinnikov
- School of Public Health, University of California Berkeley, Berkeley, CA;
| | - Paul D Blanc
- Division of Occupational and Environmental Medicine, University of California San Francisco, San Francisco, CA
| | - Craig Steinmaus
- School of Public Health, University of California Berkeley, Berkeley, CA
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Smoking Increases the Risk of Acute Mountain Sickness. Wilderness Environ Med 2015; 26:164-72. [DOI: 10.1016/j.wem.2014.10.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2014] [Revised: 10/09/2014] [Accepted: 10/13/2014] [Indexed: 11/21/2022]
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The Relationship Between Baseline Exhaled Nitric Oxide Levels and Acute Mountain Sickness. Am J Med Sci 2015; 349:467-71. [DOI: 10.1097/maj.0000000000000384] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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Vinnikov D, Brimkulov N, Krasotski V, Redding-Jones R, Blanc PD. Risk factors for occupational acute mountain sickness. Occup Med (Lond) 2014; 64:483-9. [DOI: 10.1093/occmed/kqu094] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
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McDevitt M, McIntosh SE, Rodway G, Peelay J, Adams DL, Kayser B. Risk Determinants of Acute Mountain Sickness in Trekkers in the Nepali Himalaya: a 24-Year Follow-Up. Wilderness Environ Med 2014; 25:152-9. [DOI: 10.1016/j.wem.2013.12.027] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2013] [Revised: 12/18/2013] [Accepted: 12/19/2013] [Indexed: 11/29/2022]
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MacInnis MJ, Koch S, MacLeod KE, Carter EA, Jain R, Koehle MS, Rupert JL. Acute mountain sickness is not repeatable across two 12-hour normobaric hypoxia exposures. Wilderness Environ Med 2014; 25:143-51. [PMID: 24631230 DOI: 10.1016/j.wem.2013.11.007] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Revised: 10/11/2013] [Accepted: 11/21/2013] [Indexed: 10/25/2022]
Abstract
OBJECTIVE The purposes of this experiment were to determine the repeatability of acute mountain sickness (AMS), AMS symptoms, and physiological responses across 2 identical hypoxic exposures. METHODS Subjects (n = 25) spent 3 nights at simulated altitude in a normobaric hypoxia chamber: twice at a partial pressure of inspired oxygen (PIO2) of 90mmHg (4000 m equivalent; "hypoxia") and once at a PIO2 of 132 mmHg (1000 m equivalent; "sham") with 14 or more days between exposures. The following variables were measured at hours 0 and 12 of each exposure: AMS severity (ie, Lake Louise score [LLS]), AMS incidence (LLS ≥3), heart rate, oxygen saturation, blood pressure, and the fraction of exhaled nitric oxide. Oxygen saturation and heart rate were also measured while subjects slept. RESULTS The incidence of AMS was not statistically different between the 2 exposures (84% vs 56%, P > .05), but the severity of AMS (ie, LLS) was significantly lower on the second hypoxic exposure (mean [SD], 3.1 [1.8]) relative to the first hypoxic exposure (4.8 [2.3]; P < .001). Headache was the only AMS symptom to have a significantly greater severity on both hypoxic exposures (relative to the sham exposure, P < .05). Physiological variables were moderately to strongly repeatable (intraclass correlation range 0.39 to 0.86) but were not associated with AMS susceptibility (P > .05). CONCLUSIONS The LLS was not repeatable across 2 identical hypoxic exposures. Increased familiarity with the environment (not acclimation) could explain the reduced AMS severity on the second hypoxic exposure. Headache was the most reliable AMS symptom.
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Affiliation(s)
- Martin J MacInnis
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada.
| | - Sarah Koch
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Kristin E MacLeod
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Eric A Carter
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Radha Jain
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Michael S Koehle
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada; School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
| | - Jim L Rupert
- School of Kinesiology, University of British Columbia, Vancouver, British Columbia, Canada
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MacInnis MJ, Carter EA, Freeman MG, Pandit BP, Siwakoti A, Subedi A, Timalsina U, Widmer N, Thapa GB, Koehle MS, Rupert JL. A prospective epidemiological study of acute mountain sickness in Nepalese pilgrims ascending to high altitude (4380 m). PLoS One 2013; 8:e75644. [PMID: 24130729 PMCID: PMC3794000 DOI: 10.1371/journal.pone.0075644] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2013] [Accepted: 08/16/2013] [Indexed: 01/14/2023] Open
Abstract
Background Each year, thousands of pilgrims travel to the Janai Purnima festival in Gosainkunda, Nepal (4380 m), ascending rapidly and often without the aid of pharmaceutical prophylaxis. Methods During the 2012 Janai Purnima festival, 538 subjects were recruited in Dhunche (1950 m) before ascending to Gosainkunda. Through interviews, subjects provided demographic information, ratings of AMS symptoms (Lake Louise Scores; LLS), ascent profiles, and strategies for prophylaxis. Results In the 491 subjects (91% follow-up rate) who were assessed upon arrival at Gosainkunda, the incidence of AMS was 34.0%. AMS was more common in females than in males (RR = 1.57; 95% CI = 1.23, 2.00), and the AMS incidence was greater in subjects >35 years compared to subjects ≤35 years (RR = 1.63; 95% CI = 1.36, 1.95). There was a greater incidence of AMS in subjects who chose to use garlic as a prophylactic compared to those who did not (RR = 1.69; 95% CI = 1.26, 2.28). Although the LLS of brothers had a moderate correlation (intraclass correlation = 0.40, p = 0.023), sibling AMS status was a weak predictor of AMS. Conclusions The incidence of AMS upon reaching 4380 m was 34% in a large population of Nepalese pilgrims. Sex, age, and ascent rate were significant factors in the development of AMS, and traditional Nepalese remedies were ineffective in the prevention of AMS.
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Affiliation(s)
- Martin J. MacInnis
- School of Kinesiology, University of British Columbia, Vancouver, Canada
- * E-mail:
| | - Eric A. Carter
- School of Kinesiology, University of British Columbia, Vancouver, Canada
| | | | - Bidur Prasad Pandit
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Ashmita Siwakoti
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Ankita Subedi
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Utsav Timalsina
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Nadia Widmer
- Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Ghan Bahadur Thapa
- Maharajgunj Medical Campus, Institute of Medicine, Tribhuvan University, Nepal
| | - Michael S. Koehle
- School of Kinesiology, University of British Columbia, Vancouver, Canada
- Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Jim L. Rupert
- School of Kinesiology, University of British Columbia, Vancouver, Canada
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