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Placenta Nov 2020Previous studies conducted in high altitude regions showed that maternal altitude was associated with low birth weight. The effect size of birth weight reduction is... (Meta-Analysis)
Meta-Analysis
BACKGROUND
Previous studies conducted in high altitude regions showed that maternal altitude was associated with low birth weight. The effect size of birth weight reduction is inclusive with unknown effects due to preterm birth. We systematically reviewed the literature and synthesize evidence on associations between altitude elevation from sea level and birth weight.
METHOD
We searched MEDLINE/PubMed, Embase, Scopus, Web of Science, and Cochrane database, from inception to May 5, 2020 for studies that reported maternal altitude and birth weight. Bayesian multilevel effect models were employed to estimate the effect size on birth weight (and gestational age) associated with altitude. Bayesian multilevel effect models were employed to estimate the effect size on birth weight (and gestational age) associated with altitude.
RESULTS
The systematic search identified 1020 articles, with 52 articles meeting the inclusion criteria providing 207 estimates for the association of altitude and birth weight (n = 4,428,563), and with 22 articles providing 71 estimates for gestational age (n = 2,149,627). A reduction in mean birth weight of 96.98 g was associated with every 1000 m increase in altitude across 52 studies. A statistically significant but numerically minimal effect of maternal altitude elevation was observed on the gestational age (0.3 days), corresponding to a negligible estimation of 5 g lower birth weight. A relatively high heterogeneity of between-study association (I>84.1%) and small study effect was found.
CONCLUSION
A clinically meaningful birth weight reduction was associated with maternal altitude elevation beginning from sea level. Future longitudinal studies are needed to elucidate the causal association and to understand the late effect of maternal altitude.
Topics: Altitude; Birth Weight; Female; Humans; Infant, Low Birth Weight; Infant, Newborn; Pregnancy
PubMed: 32956874
DOI: 10.1016/j.placenta.2020.09.010 -
Journal of Air Transport Management Oct 2020Commercial and private deployment of airborne drones is revolutionising many ecosystems. To identify critical issues and research gaps, our systematic literature review...
Commercial and private deployment of airborne drones is revolutionising many ecosystems. To identify critical issues and research gaps, our systematic literature review findings suggest that historic issues such as privacy, acceptance and security are increasingly replaced by operational considerations including interaction with and impacts on other airspace users. Recent incidents show that unrestricted drone use can inflict problems on other airspace users like airports and emergency services. Our review of current regulatory approaches shows a need for further policy and management response to both manage rapid and efficient drone usage growth, and facilitate innovation (e.g. intraurban package delivery), with one promising strategic response being low altitude airspace management (LAAM) systems for all drone use cases.
PubMed: 32952321
DOI: 10.1016/j.jairtraman.2020.101929 -
Reviews on Environmental Health Mar 2021Leishmaniasis is a neglected and widespread parasitic disease that can lead to serious health problems. The current review study aimed to synthesize the relationship...
OBJECTIVES
Leishmaniasis is a neglected and widespread parasitic disease that can lead to serious health problems. The current review study aimed to synthesize the relationship between ecologic and environmental factors (e.g., weather conditions, climatology, temperature and topology) and the incidence of cutaneous leishmaniasis (CL) in the Old World.
CONTENT
A systematic review was conducted based on English, and Persian articles published from 2015 to 2020 in PubMed/Medline, Science Direct, Web of Science and Google Scholar. Keywords used to search articles were leishmaniasis, environmental factors, weather condition, soil, temperature, land cover, ecologic* and topogr*. All articles were selected and assessed for eligibility according to the titles or abstracts. The quality screening process of articles was carried out by two independent authors. The selected articles were checked according to the inclusion and exclusion criteria.
SUMMARY AND OUTLOOK
A total of 827 relevant records in 2015-2020 were searched and after evaluating the articles, 23 articles met the eligibility criteria; finally, 14 full-text articles were included in the systematic review. Two different categories of ecologic/environmental factors (weather conditions, temperature, rainfall/precipitation and humidity) and land characteristics (land cover, slope, elevation and altitude, earthquake and cattle sheds) were the most important factors associated with CL incidence.
CONCLUSIONS
Temperature and rainfall play an important role in the seasonal cycle of CL as many CL cases occurred in arid and semiarid areas in the Old World. Moreover, given the findings of this study regarding the effect of weather conditions on CL, it can be concluded that designing an early warning system is necessary to predict the incidence of CL based on different weather conditions.
Topics: Africa; Asia; Australasia; Climate; Europe; Geography; Incidence; Leishmaniasis, Cutaneous; Temperature; Weather
PubMed: 32892182
DOI: 10.1515/reveh-2020-0066 -
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 -
Frontiers in Physiology 2020Under normal physiological conditions, renal tissue oxygen is tightly regulated. At high altitude, a physiological challenge is imposed by the decrease in atmospheric...
Under normal physiological conditions, renal tissue oxygen is tightly regulated. At high altitude, a physiological challenge is imposed by the decrease in atmospheric oxygen. At the level of the kidney, the physiological adaptation to high altitude is poorly understood, which might relate to different integrated responses to hypoxia over different time domains of exposure. Thus, this systematic review sought to examine the renal physiological adaptation to high altitude in the context of the magnitude and duration of exposure to high altitude in the healthy kidney model. To conduct the review, three electronic databases were examined: OVID, PubMed, and Scopus. Search terms included: Altitude, renal, and kidney. The broad, but comprehensive search, retrieved 1,057 articles published between 1997 and April 2020. Fourteen studies were included in the review. The inconsistent effect of high altitude on renal hemodynamic parameters (glomerular filtration rate, renal blood flow, and renal plasma flow), electrolyte balance, and renal tissue oxygen is difficult to interpret; however, the data suggest that the nature and extent of renal physiological adaptation at high altitude appears to be related to the magnitude and duration of the exposure. It is clear that renal physiological adaptation to high altitude is a complex process that is not yet fully understood. Further research is needed to better understand the renal physiological adaptation to hypoxia and how renal oxygen homeostasis and metabolism is defended during exposure to high altitude and affected as a long-term consequence of renal adaptation at high altitude.
PubMed: 32765289
DOI: 10.3389/fphys.2020.00756 -
Biological Research Jul 2020Arid environments are defined by the lack of water availability, which is directly related to the mean annual precipitation (MAP), and high values of solar irradiation,...
Arid environments are defined by the lack of water availability, which is directly related to the mean annual precipitation (MAP), and high values of solar irradiation, which impacts the community composition of animals, plants, and the microbial structure of the soil. Recent advances in NGS technologies have expanded our ability to characterize microbiomes, allowing environmental microbiologists to explore the complete microbial structure. Intending to identify and describe the state-of-the-art of bacterial communities in arid soils at a global scale, and to address the effect that some environmental features may have on them, we performed a systematic review based on the PRISMA guideline. Using a combination of keywords, we identified a collection of 66 studies, including 327 sampled sites, reporting the arid soil bacterial community composition by 16S rDNA gene high-throughput sequencing. To identify factors that can modulate bacterial communities, we extracted the geographical, environmental, and physicochemical data. The results indicate that even though each sampled site was catalogued as arid, they show wide variability in altitude, mean annual temperature (MAT), soil pH and electric conductivity, within and between arid environments. We show that arid soils display a higher abundance of Actinobacteria and lower abundance of Proteobacteria, Cyanobacteria, and Planctomycetes, compared with non-arid soil microbiomes, revealing that microbial structure seems to be strongly modulated by MAP and MAT and not by pH in arid soils. We observed that environmental and physicochemical features were scarcely described among studies, hence, we propose a reporting guideline for further analysis, which will allow deepening the knowledge of the relationship between the microbiome and abiotic factors in arid soil. Finally, to understand the academic collaborations landscape, we developed an analysis of the author's network, corroborating a low degree of connectivity and collaborations in this research topic. Considering that it is crucial to understand how microbial processes develop and change in arid soils, our analysis emphasizes the need to increase collaborations between research groups worldwide.
Topics: Animals; Microbiota; Plants; Proteobacteria; Soil; Soil Microbiology
PubMed: 32631429
DOI: 10.1186/s40659-020-00296-1 -
BMJ Open Respiratory Research Apr 2020Acetazolamide (AZM) is used for various conditions (eg, altitude sickness, sleep apnoea, glaucoma), but therapy is often limited by its side effect profile. Our... (Meta-Analysis)
Meta-Analysis
INTRODUCTION
Acetazolamide (AZM) is used for various conditions (eg, altitude sickness, sleep apnoea, glaucoma), but therapy is often limited by its side effect profile. Our objective was to estimate the risk of commonly reported side effects based on meta-analyses. We hypothesised that these risks are dose-dependent.
METHODS
We queried MEDLINE/EMBASE (Medical Literature Analysis and Retrieval System Online/Excerpta Medica dataBASE) up until 04/10/2019, including any randomised placebo-controlled trial in which adults received oral AZM versus placebo reporting side effects. Eligibility assessment was performed by two independent reviewers. Data were abstracted by one reviewer who verified key entries at a second time point. For side effects reported by 3 studies a pooled effect estimate was calculated, and heterogeneity assessed via I; for outcomes reported by 5 studies effect modification by total daily dose (EMbyTDD; <400 mg/d, 400-600 mg/d, >600 mg/d) was assessed via meta-regression. For pre-specified, primary outcomes (paraesthesias, taste disturbances, polyuria and fatigue) additional subgroup analyses were performed using demographics, intervention details, laboratory changes and risk of bias.
RESULTS
We included 42 studies in the meta-analyses (N=1274/1211 in AZM/placebo groups). AZM increased the risk of all primary outcomes (p<0.01, I ≤16% and low-to-moderate quality of evidence for all)-the numbers needed to harm (95% CI; n) for each were: paraesthesias 2.3 (95% CI 2 to 2.7; n=39), dysgeusia 18 (95% CI 10 to 38, n=22), polyuria 17 (95% CI 9 to 49; n=22), fatigue 11 (95% CI 6 to 24; n=14). The risk for paraesthesias (beta=1.8 (95% CI 1.1 to 2.9); P=0.01) and dysgeusia (beta=3.1 (95% CI 1.2 to 8.2); P=0.02) increased with higher AZM doses; the risk of fatigue also increased with higher dose but non-significantly (beta=2.6 (95% CI 0.7 to 9.4); P=0.14).
DISCUSSION
This comprehensive meta-analysis of low-to-moderate quality evidence defines risk of common AZM side effects and corroborates dose dependence of some side effects. These results may inform clinical decision making and support efforts to establish the lowest effective dose of AZM for various conditions.
Topics: Acetazolamide; Adult; Dose-Response Relationship, Drug; Dysgeusia; Fatigue; Humans; Paresthesia; Randomized Controlled Trials as Topic
PubMed: 32332024
DOI: 10.1136/bmjresp-2020-000557 -
PeerJ 2020Recently, several studies have investigated the prevalence of chronic obstructive pulmonary disease (COPD) at high altitude (>1,500 m). However, much remains to be...
BACKGROUND AND OBJECTIVE
Recently, several studies have investigated the prevalence of chronic obstructive pulmonary disease (COPD) at high altitude (>1,500 m). However, much remains to be understood about the correlation between altitude and COPD. We aimed to summarize the prevalence of COPD at high-altitudes and find out if altitude could be a risk factor for COPD.
METHODS
We searched PubMed/Medline, Cochrane Library, Web of Science, SCOPUS, OVID, Chinese Biomedical Literature Database (CBM) and Embase databases from inception to April 30th, 2019, with no language restriction. We used STATA 14.0 to analyze the extracted data. A random-effect model was used to calculate the combined OR and 95% CI. Heterogeneity was assessed by the statistic versus -value. We performed a subgroup analysis to analyze possible sources of heterogeneity. The Egger's test and the Begg's test were used to assess any publication bias.
RESULTS
We retrieved 4,574 studies from seven databases and finally included 10 studies (54,578 participants). Males ranged from 18.8% to 49.3% and the population who smoked ranged from 3.3% to 53.3%. The overall prevalence of COPD at high-altitude was 10.0% (95% CI [0.08-0.12], < 0.001). In a subgroup analysis, based on different regions, the results showed that the prevalence in Asia was higher than that in Europe and America. Seven studies compared the relationship between the prevalence of COPD at high-altitudes and the lowlands. The results showed that altitude was not an independent risk factor for the prevalence of COPD (OR = 1.18, 95% CI [0.85-1.62], = 0.321). There was no publication bias among the studies.
CONCLUSIONS
Our study found a higher prevalence of COPD at high-altitudes than those from average data. However, altitude was not found to be an independent risk factor for developing COPD (PROSPERO Identifier: CRD42019135012).
PubMed: 32280564
DOI: 10.7717/peerj.8586 -
Frontiers in Physiology 2019High altitude, characterized by hypobaric hypoxia, low temperature, and intensive ultraviolet radiation, is identifiably one of the examples of scientific enquiry into...
High altitude, characterized by hypobaric hypoxia, low temperature, and intensive ultraviolet radiation, is identifiably one of the examples of scientific enquiry into aviation and space analogs. However, little is known about the ocular physiological response, especially intraocular pressure (IOP) changes at high altitude. This study aimed to systematically review of high altitude exposure on IOP for healthy lowlanders with unoperated eyes. A comprehensive systematic literature search was conducted in the electronic databases until September 1st, 2019. A meta-analysis was performed following the preferred reporting items for systematic review and meta-analysis statement (PRISMA). We systematically searched the studies conducted over 2,000 m above sea level (a.s.l) in healthy lowlanders with measurements of IOP. Meta-analyses (random effect model and heterogeneity tests), subgroup analyses (altitude, duration, type, and pattern of exposure), sensitivity analysis, funnel plot, Begger's and Egger's test for publication bias were performed. Quality assessment was conducted using the Newcastle-Ottawa scale. The meta-analysis was registered in the PROSPERO database (CRD42019136865). Of 9595 publications searched, 20 publications ( = 745) qualified for inclusion, with non-significant decrease in overall IOP [standardized mean difference (SMD): 0.14, 95% CI: -0.12-0.40; = 0.30] with high heterogeneity ( < 0.001, = 82%). However, subgroup analyses revealed significant decrease of IOP at high altitude of 3,000-5,500 m a.s.l (SMD: 0.57, 95% CI: 0.07-1.06; = 0.03) whereas increase of IOP at extreme altitude of over 5,500 m a.s.l (SMD: -0.34, 95% CI: -0.61-0.06; = 0.02). And the duration of exposure more than 72 hours (h) was likely to induce a decrease of IOP bordering on statistical significance at the 5% level (SMD: 1.29, 95% CI: 0.02-2.56; = 0.05). Simultaneously, we also observed significant decrease of IOP for active exposure (e.g., physical activity and hiking, SMD: 0.81, 95% CI: 0.05-1.57; = 0.04). Our analysis shows exposure to the altitude over 3,500 m a.s.l, duration of exposure more than 72 h and active exposure pattern may have modest, but significant effects on IOP. The higher altitude, the duration of exposure as well as physical activity seem to play crucial roles in the effects of high-altitude exposure on IOP.
PubMed: 31780951
DOI: 10.3389/fphys.2019.01366 -
Nutricion Hospitalaria Oct 2019High altitude mountaineering is characterized by high energetic requirements due to the environment in which the activity is developed: negative energy balance, extreme...
High altitude mountaineering is characterized by high energetic requirements due to the environment in which the activity is developed: negative energy balance, extreme cold, high altitude and the assumption of potential risks can be found during the practice of this sport. High altitude mountaineering, as a result of the previous factors, induces changes in body composition which have never been studied previously in a systematic review. A search within four different databases (PubMed, SportDiscus, Scopus and Medline) was performed using the thesaurus terms "Mountaineering" and "Body composition". A second search was performed using the following terms "Altitude" and "Body composition". The selection criteria included studies with healthy adults which evaluated the effects of at least 14 days of uninterrupted stays at altitudes above 4,000 m. The studies included in the review assessed body composition through different methods such as anthropometry, bioimpedance, dual energy x-ray absorptiometry, hydrostatic weighing and air displacement plethysmography. The search was performed up to and including December 1st 2018. Eleven observational studies met the inclusion criteria. All studies reported weight loss, of which five reported significant reductions in lean mass and six reported reductions in fat mass. Also, three studies reported reductions in both fat mass and lean mass. Current evidence is limited to observational studies with important confounding factors affecting the final conclusions. Longitudinal studies with a better methodological design and control groups are needed in order to verify these results.
Topics: Altitude; Body Composition; Humans; Mountaineering
PubMed: 31516006
DOI: 10.20960/nh.02582