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Scientific Reports Aug 2016Nasal potential difference (NPD), a well-established in vivo clinical test for cystic fibrosis, reflects transepithelial cation and anion transport in the respiratory... (Meta-Analysis)
Meta-Analysis Review
Nasal potential difference (NPD), a well-established in vivo clinical test for cystic fibrosis, reflects transepithelial cation and anion transport in the respiratory epithelium. To analyze whether NPD can be applied to diagnose hypoxic lung injury, we searched PubMed, EMBASE, Scopus, Web of Science, Ovid MEDLINE, and Google Scholar, and analyzed data retrieved from eleven unbiased studies for high altitude pulmonary edema (HAPE) and respiratory distress syndrome (RDS) using the software RevMan and R. There was a significant reduction in overall basal (WMD -5.27 mV, 95% CI: -6.03 to -4.52, P < 0.00001, I(2) = 42%), amiloride-sensitive (ENaC) (-2.87 mV, 95% CI: -4.02 to -1.72, P < 0.00001, I(2) = 51%), and -resistant fractions (-3.91 mV, 95% CI: -7.64 to -0.18, P = 0.04, I(2) = 95%) in lung injury patients. Further analysis of HAPE and RDS separately corroborated these observations. Moreover, SpO2 correlated with ENaC-associated NPD positively in patients only, but apparently related to CFTR-contributed NPD level inversely. These correlations were confirmed by the opposite associations between NPD values and altitude, which had a negative regression with SpO2 level. Basal NPD was significantly associated with amiloride-resistant but not ENaC fraction. Our analyses demonstrate that acute lung injury associated with systemic hypoxia is characterized by dysfunctional NPD.
Topics: Acute Lung Injury; Adult; Altitude Sickness; Female; Humans; Hypertension, Pulmonary; Male; Middle Aged; Respiratory Distress Syndrome; Software
PubMed: 27488696
DOI: 10.1038/srep30780 -
Therapeutic Advances in Respiratory... Jan 2017Acetazolamide has been investigated for treating sleep apnea in newcomers ascending to high altitude. This study aimed to assess the effect of acetazolamide on sleep... (Meta-Analysis)
Meta-Analysis Review
BACKGROUND
Acetazolamide has been investigated for treating sleep apnea in newcomers ascending to high altitude. This study aimed to assess the effect of acetazolamide on sleep apnea at high altitude, determine the optimal therapeutic dose, and compare its effectiveness in healthy trekkers and obstructive sleep apnea (OSA) patients.
METHODS
PubMed, Embase, Scopus, Cochrane Library, and Airiti Library databases were searched up to July 2015 for randomized controlled trials (RCTs) performed above 2500 m in lowlanders and that used acetazolamide as intervention in sleep studies. Studies including participants with medical conditions other than OSA were excluded.
RESULTS
Eight studies of 190 adults were included. In healthy participants, the pooled mean effect sizes of acetazolamide on Apnea-Hypopnea Index (AHI), percentage of periodic breathing time, and nocturnal oxygenation were 34.66 [95% confidence interval (CI) 25.01-44.30] with low heterogeneity ( p = 0.7, I = 0%), 38.56% (95% CI 18.92-58.19%) with low heterogeneity ( p = 0.24, I = 28%), and 4.75% (95% CI 1.35-8.15%) with high heterogeneity ( p < 0.01, I = 87%), respectively. In OSA patients, the pooled mean effect sizes of acetazolamide on AHI and nocturnal oxygenation were 13.18 (95% CI 9.25-17.1) with low heterogeneity ( p = 0.33, I = 0%) and 1.85% (95% CI 1.08-2.62%) with low heterogeneity ( P = 0.56, I = 0%).
CONCLUSIONS
Acetazolamide improves sleep apnea at high altitude by decreasing AHI and percentage of periodic breathing time and increasing nocturnal oxygenation. Acetazolamide is more beneficial in healthy participants than in OSA patients, and a 250 mg daily dose may be as effective as higher daily doses for healthy trekkers.
Topics: Acetazolamide; Adult; Altitude; Carbonic Anhydrase Inhibitors; Dose-Response Relationship, Drug; Humans; Oxygen Consumption; Randomized Controlled Trials as Topic; Sleep Apnea Syndromes; Sleep Apnea, Obstructive
PubMed: 28043212
DOI: 10.1177/1753465816677006 -
Heliyon Sep 2023With a growing number of athletes and coaches adopting altitude training, the importance for rationalizing and optimizing such training has been emphasized. We conducted...
PURPOSE
With a growing number of athletes and coaches adopting altitude training, the importance for rationalizing and optimizing such training has been emphasized. We conducted a meta-analysis to evaluate the influence of altitude training on athletes' aerobic capacity and to explore the best altitude training method to improve this capacity.
METHODS
We searched Web of Science, SpringerLink, Science Direct, EBSCO, and PubMed databases combined with manual search of the references to collect studies indexed from 1979 to September 2020 on the effect of altitude training on athletes' aerobic capacity. Data from experimental studies that reported hemoglobin levels and maximum oxygen uptake in athletes before and after altitude training, or in athletes performing altitude training in comparison with a control group were analyzed. Data of the populations, intervention, comparison, outcomes and study design were extracted. Review Manager software 5.3 was used for bias evaluation.
RESULTS
17 publications were included. In our meta-analysis, altitude training led to higher maximum oxygen uptake [standardized mean difference (SMD) = 0.67, 95% confidence interval (CI) 0.35-1.00, P < 0.001] and hemoglobin level (SMD = 0.50, 95% CI 0.11-0.90, P = 0.013) than training at lower altitude. The result of sensitivity analysis showed that results of meta-analysis were relatively stable, and there was no bias or change in the result of effect size according to the bias test. The results of subgroup analysis showed that high-altitude living and low-altitude training ("Hi-Lo" regime), with a training cycle of about three weeks at an altitude around 2500 m, had better effects than other regimes on the athletes' aerobic capacity.
CONCLUSIONS
Altitude training can improve athletes' aerobic capacity in terms of maximum oxygen uptake and hemoglobin level. Our results are limited by the number and quality of available studies. Therefore, more high-quality studies are needed to verify and extend these findings. Our study can provide scientific suggestions for the training of athletes.
PubMed: 37809554
DOI: 10.1016/j.heliyon.2023.e20188 -
BMJ Clinical Evidence Mar 2010Up to half of people who ascend to heights above 2500 m may develop acute mountain sickness, pulmonary oedema, or cerebral oedema, with the risk being greater at higher... (Review)
Review
INTRODUCTION
Up to half of people who ascend to heights above 2500 m may develop acute mountain sickness, pulmonary oedema, or cerebral oedema, with the risk being greater at higher altitudes, and with faster rates of ascent.
METHODS AND OUTCOMES
We conducted a systematic review and aimed to answer the following clinical questions: What are the effects of interventions to prevent, and to treat, acute mountain sickness? We searched: Medline, Embase, The Cochrane Library, and other important databases up to October 2009 (Clinical Evidence reviews are updated periodically, please check our website for the most up-to-date version of this review). We included harms alerts from relevant organisations such as the US Food and Drug Administration (FDA) and the UK Medicines and Healthcare products Regulatory Agency (MHRA).
RESULTS
We found 17 systematic reviews, RCTs, or observational studies that met our inclusion criteria. We performed a GRADE evaluation of the quality of evidence for interventions.
CONCLUSIONS
In this systematic review we present information relating to the effectiveness and safety of the following interventions: acetazolamide, descent versus resting, dexamethasone, gingko biloba, and slow ascent.
Topics: Acetazolamide; Acute Disease; Altitude; Altitude Sickness; Ginkgo biloba; Humans; Pulmonary Edema
PubMed: 21718562
DOI: No ID Found -
Frontiers in Physiology 2023This study aimed to compare and rank the effect of hypoxic practices on maximum oxygen consumption (VOmax) in athletes and determine the hypoxic dose-response... (Review)
Review
This study aimed to compare and rank the effect of hypoxic practices on maximum oxygen consumption (VOmax) in athletes and determine the hypoxic dose-response correlation using network meta-analysis. The Web of Science, PubMed, EMBASE, and EBSCO databases were systematically search for randomized controlled trials on the effect of hypoxc interventions on the VOmax of athletes published from inception until 21 February 2023. Studies that used live-high train-high (LHTH), live-high train-low (LHTL), live-high, train-high/low (HHL), intermittent hypoxic training (IHT), and intermittent hypoxic exposure (IHE) interventions were primarily included. LHTL was further defined according to the type of hypoxic environment (natural and simulated) and the altitude of the training site (low altitude and sea level). A meta-analysis was conducted to determine the standardized mean difference between the effects of various hypoxic interventions on VOmax and dose-response correlation. Furthermore, the hypoxic dosage of the different interventions were coordinated using the "kilometer hour" model. From 2,072 originally identified titles, 59 studies were finally included in this study. After data pooling, LHTL, LHTH, and IHT outperformed normoxic training in improving the VOmax of athletes. According to the P-scores, LHTL combined with low altitude training was the most effective intervention for improving VOmax (natural: 0.92 and simulated: 0.86) and was better than LHTL combined with sea level training (0.56). A reasonable hypoxic dose range for LHTH (470-1,130 kmh) and HL (500-1,415 kmh) was reported with an inverted U-shaped curve relationship. Different types of hypoxic training compared with normoxic training serve as significant approaches for improving aerobic capacity in athletes. Regardless of the type of hypoxic training and the residential condition, LHTL with low altitude training was the most effective intervention. The characteristics of the dose-effect correlation of LHTH and LHTL may be associated with the negative effects of chronic hypoxia.
PubMed: 37745240
DOI: 10.3389/fphys.2023.1223037 -
Medicina (Kaunas, Lithuania) Mar 2022: Metabolic syndrome (MS) has many risk factors that are important to investigate in populations living at sea level and in high-altitude geographic regions. The aim was... (Review)
Review
: Metabolic syndrome (MS) has many risk factors that are important to investigate in populations living at sea level and in high-altitude geographic regions. The aim was to identify the components of MS that cross-sectional studies use to assess in adult populations residing in high-altitude regions. : A systematic review study was conducted. The Pubmed database was used. The search for original articles (cross-sectional) was performed from January 2013 to December 2020. The procedure was carried out by two researchers. The keywords used were metabolic syndrome, adults, and altitude regions. The search strategy considered the components of the PICOS tool. Ten cross-sectional studies were identified in the Pubmed database from 2014 to 2020. Altitude levels varied between countries and regions, from 2060 to 4900 m above sea level. Three studies were conducted in both China and Peru, two studies in Ecuador, and one in Bolivia and India. The age ranges studied were from 18 to ~80 years of age, approximately. The components used to assess MS in most studies (between 9 to 10 studies) were body mass index (BMI), waist circumference (WC), blood pressure (BP), triglycerides (TG), high-density lipoproteins (HDL) and serum glucose (SG). : This systematic review verified that the most commonly used domains in adult populations in various moderate- and high-altitude regions of the world are BMI, WC, BP, TG, HDL, and SG. These results suggest that in order to evaluate and/or investigate MS in subjects residing in high-altitude populations, at least four diagnostic domains should be considered in their protocols.
Topics: Adolescent; Adult; Altitude; Body Mass Index; Cross-Sectional Studies; Humans; Metabolic Syndrome; Waist Circumference
PubMed: 35334627
DOI: 10.3390/medicina58030451 -
Journal of Reproduction & Infertility 2023Cell-free fetal DNA (cffDNA) is a novel screening method for fetal aneuploidy that facilitated non-invasive prenatal testing (NIPT) through analysis of cffDNA in... (Review)
Review
BACKGROUND
Cell-free fetal DNA (cffDNA) is a novel screening method for fetal aneuploidy that facilitated non-invasive prenatal testing (NIPT) through analysis of cffDNA in maternal plasma. However, despite increased sensitivity, it has a number of limitations that may complicate of its results interpretation. Therefore, elucidating factors affecting fetal fraction, as a critical limitation, guides its clinical application.
METHODS
In this report, systematic search was carried out through PubMed, Web of Science, and Scopus databases until February 11, 2022 by using keywords consist of "noninvasive prenatal screening", "NIPT", "noninvasive prenatal", "cell free DNA" and "fetal fraction". The articles were screened for eligibility criteria before data extraction.
RESULTS
A total of 39 eligible studies, most published between 2010 and 2020, were included. Based on the results of studies, a negative correlation between maternal age and BMI/body weight with fetal fraction was found. Furthermore, LDL, cholesterol, triglyceride level, metformin, heparin and enoxaparin therapy, hemoglobin-related hemoglobinopathies, and physical activity showed to have negative associations. Interestingly, it seems the ethnicity of patients from South and East Asia has a correlation with fetal fraction compared to Caucasians. Positive correlation was observed between gestational age, free β-hCG, PAPP-A, living in high altitude, and twin pregnancy.
CONCLUSION
Considering each factor, there was significant inconsistency and controversy regarding their impact on outcomes. Indeed, multiple factors can influence the accuracy of NIPS results, and it is worth noting that the impact of these factors may vary depending on the individual's ethnic background. Therefore, it is important to recognize that NIPS remains a screening test, and comprehensive pre- and post-NIPS counseling should be conducted as part of standard clinical practice.
PubMed: 38164433
DOI: 10.18502/jri.v24i4.14149 -
Journal of the Endocrine Society Sep 2022Pheochromocytomas and paragangliomas (PPGLs) are known to be rare. However, there is scant literature reporting their epidemiology, particularly whether the diagnosis of...
CONTEXT
Pheochromocytomas and paragangliomas (PPGLs) are known to be rare. However, there is scant literature reporting their epidemiology, particularly whether the diagnosis of PPGL has increased with advances in medical imaging and biochemical and genetic testing.
OBJECTIVE
The primary objective of this systematic review was to determine the annual incidence of PPGLs and change over time.
DESIGN
A systematic review was performed. Medline, Embase, PubMed, and Web of Science Core Collection databases were searched to identify studies reporting PPGL incidence. Studies were eligible for inclusion from the database's inception until August 30, 2021.
RESULTS
A total of 6109 manuscripts were identified; 2282 duplicates were excluded, and a further 3815 papers were excluded after abstract and/or full text review. Twelve studies were included in the final review. The incidence of PPGL ranged from 0.04 to 0.95 cases per 100 000 per year. Incidence increased over time, from approximately 0.2/100,000 individuals in studies performed before 2000, to approximately 0.6/100,000 in studies undertaken after 2010. The mode of diagnosis changed over the same time period, with more patients diagnosed from incidental imaging findings, and fewer at autopsy or from symptoms.
CONCLUSION
The annual incidence of PPGL has increased over time. Much of this increase is likely from incidental identification of tumors on imaging. However, the epidemiology of PPGL remains understudied, in particular, in associations with altitude, ethnicity, and genetics. To improve early detection and management guidelines, these gaps should be addressed.
PubMed: 35919261
DOI: 10.1210/jendso/bvac105 -
Aerospace Medicine and Human Performance Feb 2017Flights to high altitude can lead to exposure and unique pathology not seen in normal commercial aviation. (Review)
Review
INTRODUCTION
Flights to high altitude can lead to exposure and unique pathology not seen in normal commercial aviation.
METHODS
This paper assesses the potential for point-of-care ultrasound to aid in management and disposition of injured crewmembers from a high altitude incident. This was accomplished through a systematic literature review regarding current diagnostic and therapeutic uses of ultrasound for injuries expected in high altitude free fall and parachuting.
RESULTS
While current research supports its utility in diagnostics, therapeutic procedures, and triage decisions, little research has been done regarding its utility in high altitude specific pathology, but its potential has been demonstrated.
DISCUSSION
An algorithm was created for use in high altitude missions, in the event of an emergency descent and traumatic landing for an unconscious and hypotensive pilot, to rule out most life threatening causes. Each endpoint includes disposition, allowing concise decision-making.Galdamez LA, Clark JB, Antonsen EL. Point-of-care ultrasound utility and potential for high altitude crew recovery missions. Aerosp Med Hum Perform. 2017; 88(2):128-136.
Topics: Aerospace Medicine; Altitude; Aviation; Barotrauma; Cardiac Tamponade; Clinical Decision-Making; Contusions; Decompression Sickness; Diaphragm; Emergency Medical Services; Fractures, Bone; Humans; Pericardial Effusion; Pleural Effusion; Pneumothorax; Point-of-Care Systems; Pulmonary Atelectasis; Pulmonary Edema; Surgery, Computer-Assisted; Ultrasonography
PubMed: 28095957
DOI: 10.3357/AMHP.4640.2017 -
Obesity Reviews : An Official Journal... Feb 2021The associations between built and food environments and childhood obesity have been studied extensively. However, the association between the natural environment and...
The associations between built and food environments and childhood obesity have been studied extensively. However, the association between the natural environment and childhood obesity has received too little scholarly attention. This study reviewed the literature published before 1 January 2019, which described associations between a full range of natural environmental factors (e.g., rainfall, temperature, sunlight, natural disasters, flood and drought) and weight-related behaviours and childhood obesity. Five cross-sectional studies and one longitudinal study were identified. Measures of natural environmental factors varied across six included studies, falling into five broad categories: weather conditions, altitude, natural disaster risk, air quality and day length. It was found that temperature was a significant weather indicator in most included studies and was associated with a reduction of daily physical activity. Children living in high-altitude areas were more likely to be shorter and heavier than their counterparts in low-altitude areas. Findings of this study will contribute to helping multiple stakeholders, including policy makers and urban planners, and formulate health policies and interventions to mitigate the detrimental impact of the natural environment on childhood obesity. More longitudinal studies should be designed to confirm these effects and explore the potential health effects of more natural environmental factors.
Topics: Air Pollution; Child; Cross-Sectional Studies; Exercise; Humans; Longitudinal Studies; Pediatric Obesity
PubMed: 32869468
DOI: 10.1111/obr.13097