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International Journal of Environmental... Jul 2022(1) Background: While previous studies revealed how underground mining might adversely affect the cardiopulmonary functions of workers, this study further investigated...
(1) Background: While previous studies revealed how underground mining might adversely affect the cardiopulmonary functions of workers, this study further investigated the differences between under- and aboveground mining at both high and low altitudes, which has received little attention in the literature. (2) Methods: Seventy-one healthy male coal mine workers were recruited, who had worked at least 5 years at the mining sites located above the ground at high (>3900 m; n = 19) and low (<120 m; n = 16) altitudes as well as under the ground at high (n = 20) and low (n = 16) altitudes. Participants’ heart rates, pulmonary functions, total energy expenditure and metabolism were measured over a 5-consecutive-day session at health clinics. (3) Results: Combining the results for both above- and underground locations, workers at high-altitude mining sites had significantly higher peak heart rate (HR), minimum average HR and training impulse as well as energy expenditure due to all substances and due to fat than those at low-altitude sites. They also had significantly higher uric acid, total cholesterol, creatine kinase and N-osteocalcin in their blood samples than the workers at low-altitude mining sites. At underground worksites, the participants working at high-altitude had a significantly higher average respiratory rate than those at low-altitude regions. (4) Conclusion: In addition to underground mining, attention should be paid to high-altitude mining as working under a hypoxia condition at such altitude likely presents physiological challenges.
Topics: Altitude; Coal; Coal Mining; Humans; Male; Miners; Occupational Exposure; Workplace
PubMed: 35886146
DOI: 10.3390/ijerph19148295 -
Postgraduate Medical Journal Jul 1979In studies concerned with the performance at high altitude it is often not possible to separate the effects which are due to hypoxia from those associated with the...
In studies concerned with the performance at high altitude it is often not possible to separate the effects which are due to hypoxia from those associated with the stress of ascent. Some of the basic observations concerning exercise at high altitude are reviewed and a study is described which was designed to simulate the physical exertion of high altitude mountaineering but performed at altitudes below 1000 m. Some of the changes observed including peripheral oedema might under other circumstances have been ascribed to altitude.
Topics: Altitude; Altitude Sickness; Edema; Extracellular Space; Humans; Hypoxia; Intracellular Fluid; Mountaineering; Physical Exertion; Sports Medicine
PubMed: 493203
DOI: 10.1136/pgmj.55.645.492 -
PloS One 2020A Demographic and Family Health Survey (ENDES, for Encuesta Demográfica y de Salud Familiar in Spanish) is carried out annually in Peru. Based on it, the anemia...
BACKGROUND
A Demographic and Family Health Survey (ENDES, for Encuesta Demográfica y de Salud Familiar in Spanish) is carried out annually in Peru. Based on it, the anemia prevalence was 43.6% in 2016 and 43.8% in 2017 using the WHO cutoff value of 11 g/dL and the altitude-correction equation.
OBJECTIVE
To assess factors contributing to anemia and to determine its prevalence in Peruvian children 6 to 35 months old.
METHODS
We used the MEASURE DHS-based ENDES survey to obtain representative data for11364 children from 6 to 35 months old on hemoglobin and health determinants. To evaluate normal hemoglobin levels, we used the original WHO criterion of the 5th percentile in children without chronic malnutrition and then applied it to the overall population. Relationships between hemoglobin and altitude levels, usage of cleaning methods to sanitize water safe to drink, usage of solid fuels and poverty status were tested using methodology for complex survey data. Percentile curves were made for altitude intervals by plotting hemoglobin compared to age. The new anemia rates are presented in graphs by Peruvian political regions according to the degree of public health significance.
RESULTS
Hemoglobin increased as age and altitude of residence increased. Using the 5th percentile, anemia prevalence was 7.3% in 2016 and 2017. Children from low altitudes had higher anemia prevalence (8.5%) than those from high altitudes (1.2%, p<0.0001). In the rainforest area of Peru, anemia prevalence was highest (13.5%), while in the highlands it was lowest (3.3%, p<0.0001). With access to safe drinking water and without chronic malnutrition, anemia rates could be reduced in the rainforest by 45% and 33%, respectively.
CONCLUSION
Anemia prevalence in Peruvian children from 6 to 35 months old was 7.3% in 2016 and 2017.
Topics: Age Distribution; Altitude; Anemia; Child, Preschool; Female; Humans; Infant; Male; Peru; Prevalence
PubMed: 31940318
DOI: 10.1371/journal.pone.0226846 -
Journal of Molecular Medicine (Berlin,... Dec 2017About 1.2 to 33% of high-altitude populations suffer from Monge's disease or chronic mountain sickness (CMS). Number of factors such as age, sex, and population of... (Review)
Review
About 1.2 to 33% of high-altitude populations suffer from Monge's disease or chronic mountain sickness (CMS). Number of factors such as age, sex, and population of origin (older, male, Andean) contribute to the percentage reported from a variety of samples. It is estimated that there are around 83 million people who live at altitudes > 2500 m worldwide and are at risk for CMS. In this review, we focus on a human "experiment in nature" in various high-altitude locations in the world-namely, Andean, Tibetan, and Ethiopian populations that have lived under chronic hypoxia conditions for thousands of years. We discuss the adaptive as well as mal-adaptive changes at the genomic and physiological levels. Although different genes seem to be involved in adaptation in the three populations, we can observe convergence at genetic and signaling, as well as physiological levels. What is important is that we and others have shown that lessons learned from the genes mined at high altitude can be helpful in better understanding and treating diseases that occur at sea level. We discuss two such examples: EDNRB and SENP1 and their role in cardiac tolerance and in the polycythemic response, respectively.
Topics: Adaptation, Physiological; Altitude; Founder Effect; Genetics, Population; Genomics; Humans; Hypoxia
PubMed: 28951950
DOI: 10.1007/s00109-017-1584-7 -
International Journal of Environmental... Sep 2022To evaluate the association between altitude and cardiometabolic risk calculated with the weight-height ratio (WHtR) in the Peruvian adult population via the...
To evaluate the association between altitude and cardiometabolic risk calculated with the weight-height ratio (WHtR) in the Peruvian adult population via the cross-sectional data analysis of the Peruvian Demographic and Health Survey 2021. A total of 26,117 adults from 18 to 64 years of age were included in the analysis. The dependent variable was cardiometabolic risk, defined as "Yes" if the WHtR was ≥0.5 and "No" if the WHtR was <0.5. Exposure was altitude of residence categorized as: <1500 meters above sea level (masl); 1500 to 2499 masl; 2500 to 3499 masl; and ≥3500 masl. Crude and adjusted Poisson regression models were used to calculate prevalence ratios (PR) with 95% confidence intervals (CI). The mean WHtR in the population was 0.59 (standard deviation: 0.08), and 87.6% (95% CI: 86.9-88.2) were classified as at risk. After adjusting for sex, age, education level, well-being index, and area of residence, living at altitudes between 2500 and 3499 masl (aPR: 0.98; 95% CI: 0.96-1.00) and ≥3500 masl (aPR: 0.95; 95% CI: 0.93-0.97) were associated with lower cardiometabolic risk in comparison with living at <1500 masl. An inverse association was identified between living at a higher altitude and the proportion of cardiometabolic risk in the Peruvian adult population. However, at least 8 out of 10 people were identified as at risk in all categories of altitude.
Topics: Adult; Altitude; Body Mass Index; Cardiovascular Diseases; Cross-Sectional Studies; Data Analysis; Humans; Peru; Risk Factors; Waist Circumference; Waist-Height Ratio
PubMed: 36141764
DOI: 10.3390/ijerph191811494 -
PloS One 2021The first decades of the 21st century have witnessed a renewed interest in the relationship between language structure and the various social and ecological niches in...
The first decades of the 21st century have witnessed a renewed interest in the relationship between language structure and the various social and ecological niches in which the languages of the world are used and against the background of which they evolved. In this context, Everett (2013) argued for direct geographical influences on the sound structure of languages. It was observed that ejective consonants, produced with a sudden burst of non-pulmonic air to a salient acoustic effect, tend to occur in high-altitude environments in which these sounds may be adaptive due to a reduced articulatory effort and/or to prevent desiccation. Here, we evaluate this claim and at the same time place it into a broader context. We observe that the distribution of another class of typologically unusual sounds, uvulars, is highly similar to that of ejectives, but that the proposed explanations are not available to account for the similar geographical patterning of uvulars. Hence, we test an alternative explanatory account that would posit indirect rather than direct environmental influences on language structure that are mediated by anthropological factors, in particular the relative sociolinguistic isolation of speech communities at the highest altitudes. Applying Bayesian Logistic Mixed Effects Regression to a large database of phonological inventories of the world's languages, however, we do not find strong support for either a correlation of ejectives or uvulars with high-altitude environments, though the association is somewhat stronger for ejectives than uvulars. A phylogenetic exploration of the development of both classes of sounds in two large language families spoken in widely different environments, Indo-European and Sino-Tibetan, together with a qualitative assessment of the dedicated literature, in contrast, suggests a strong role of language contact rather than environmental factors.
Topics: Altitude; Geography; Humans; Language; Phonetics; Sound; Speech Acoustics
PubMed: 33544750
DOI: 10.1371/journal.pone.0245522 -
BioMed Research International 2022People living in a high-altitude environment have distinct lifelong challenges. Adaptive mechanisms have allowed high-altitude residents to survive in a low-oxygen... (Review)
Review
People living in a high-altitude environment have distinct lifelong challenges. Adaptive mechanisms have allowed high-altitude residents to survive in a low-oxygen environment for thousands of years. The purpose of this review was to provide a brief review of the Ethiopian native highlanders' adaptive mechanisms to chronic hypoxia problems at high altitude. Traditionally, an elevated hemoglobin concentration has been considered as a hallmark of lifelong adaptation to high-altitude hypoxia, though this notion has been refuted recently as a result of the establishment of the alternative adaptive responses found in Amhara highlanders living in the Simien Mountains of northern Ethiopia. These populations did not have elevated hemoglobin (no erythrocytosis) but had normal hemoglobin saturation and arterial oxygen level, which alerts researchers to explore the possibility of the presence of an alternative adaptive mechanism. Contrary to this, Oromos living in the Bale Mountains of southern Ethiopia have elevated hemoglobin. The presence of increased nitric oxide (NO) and cyclic guanosine monophosphate (cGMP) in native Amhara highlanders suggests the possibility of adaptation via vasodilation, which would improve oxygen supply to metabolic tissues. Native Amhara highlanders showed no indications of chronic mountain sickness and had a higher pulmonary blood pressure without having a higher pulmonary vascular resistance. In addition, the cerebral circulation is sensitive to NO and carbon dioxide (CO) but not to hypoxia, which would likely promote increased cerebral blood flow and increase oxygen delivery to the brain, making Ethiopian high-altitude natives better suited for survival at high altitudes. Further research is warranted to translate these background natural features of Ethiopian native highlanders to clinical applications.
Topics: Adaptation, Physiological; Altitude; Altitude Sickness; Ethiopia; Hemoglobins; Humans; Hypoxia; Nitric Oxide; Oxygen
PubMed: 35463974
DOI: 10.1155/2022/5749382 -
Annals of the New York Academy of... Aug 2019The correct interpretation of hemoglobin (Hb) to identify anemia requires adjusting for altitude and smoking. Current adjustments were derived using data collected...
The correct interpretation of hemoglobin (Hb) to identify anemia requires adjusting for altitude and smoking. Current adjustments were derived using data collected before 1985, from low-income preschool-aged children (PSC) in the United States and indigenous men in Peru for altitude, and from White women of reproductive age (WRA) in the United States for smoking. Given the oldness and limited representativeness of these data, we reexamined associations between Hb and altitude and/or smoking using 13 population-based surveys and 1 cohort study each conducted after 2000. All WHO regions except South-East Asia were represented. The dataset included 68,193 observations among PSC (6-59 months) and nonpregnant WRA (15-49 years) with data on Hb and altitude (-28 to 4000 m), and 19,826 observations among WRA with data on Hb and smoking (status or daily cigarette quantity). Generalized linear models were used to assess the robustness of associations under varying conditions, including controlling for inflammation-corrected iron and vitamin A deficiency. Our study confirms that Hb should be adjusted for altitude and/or smoking; these adjustments are additive. However, recommendations for Hb adjustment likely need updating. Notably, current recommendations may underadjust Hb for light smokers and for those residing at lower altitudes and overadjust Hb for those residing at higher altitudes.
Topics: Adolescent; Adult; Altitude; Anemia; Child, Preschool; Female; Hemoglobins; Humans; Infant; Male; Middle Aged; Peru; Smoking; United States; Young Adult
PubMed: 31231812
DOI: 10.1111/nyas.14167 -
JMIR MHealth and UHealth Jul 2023Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the... (Clinical Trial)
Clinical Trial
BACKGROUND
Cardiorespiratory fitness plays an important role in coping with hypoxic stress at high altitudes. However, the association of cardiorespiratory fitness with the development of acute mountain sickness (AMS) has not yet been evaluated. Wearable technology devices provide a feasible assessment of cardiorespiratory fitness, which is quantifiable as maximum oxygen consumption (VOmax) and may contribute to AMS prediction.
OBJECTIVE
We aimed to determine the validity of VOmax estimated by the smartwatch test (SWT), which can be self-administered, in order to overcome the limitations of clinical VOmax measurements. We also aimed to evaluate the performance of a VOmax-SWT-based model in predicting susceptibility to AMS.
METHODS
Both SWT and cardiopulmonary exercise test (CPET) were performed for VOmax measurements in 46 healthy participants at low altitude (300 m) and in 41 of them at high altitude (3900 m). The characteristics of the red blood cells and hemoglobin levels in all the participants were analyzed by routine blood examination before the exercise tests. The Bland-Altman method was used for bias and precision assessment. Multivariate logistic regression was performed to analyze the correlation between AMS and the candidate variables. A receiver operating characteristic curve was used to evaluate the efficacy of VOmax in predicting AMS.
RESULTS
VOmax decreased after acute high altitude exposure, as measured by CPET (25.20 [SD 6.46] vs 30.17 [SD 5.01] at low altitude; P<.001) and SWT (26.17 [SD 6.71] vs 31.28 [SD 5.17] at low altitude; P<.001). Both at low and high altitudes, VOmax was slightly overestimated by SWT but had considerable accuracy as the mean absolute percentage error (<7%) and mean absolute error (<2 mL·kg·min), with a relatively small bias compared with VOmax-CPET. Twenty of the 46 participants developed AMS at 3900 m, and their VOmax was significantly lower than that of those without AMS (CPET: 27.80 [SD 4.55] vs 32.00 [SD 4.64], respectively; P=.004; SWT: 28.00 [IQR 25.25-32.00] vs 32.00 [IQR 30.00-37.00], respectively; P=.001). VOmax-CPET, VOmax-SWT, and red blood cell distribution width-coefficient of variation (RDW-CV) were found to be independent predictors of AMS. To increase the prediction accuracy, we used combination models. The combination of VOmax-SWT and RDW-CV showed the largest area under the curve for all parameters and models, which increased the area under the curve from 0.785 for VOmax-SWT alone to 0.839.
CONCLUSIONS
Our study demonstrates that the smartwatch device can be a feasible approach for estimating VOmax. In both low and high altitudes, VOmax-SWT showed a systematic bias toward a calibration point, slightly overestimating the proper VOmax when investigated in healthy participants. The SWT-based VOmax at low altitude is an effective indicator of AMS and helps to better identify susceptible individuals following acute high-altitude exposure, particularly by combining the RDW-CV at low altitude.
TRIAL REGISTRATION
Chinese Clinical Trial Registry ChiCTR2200059900; https://www.chictr.org.cn/showproj.html?proj=170253.
Topics: Humans; Acute Disease; Altitude; Altitude Sickness; Exercise Test; Oxygen Consumption
PubMed: 37410528
DOI: 10.2196/43340 -
BMC Pulmonary Medicine Apr 2022Peak inspiratory and expiratory flows (PIF, PEF) are parameters used to evaluate the mechanics of the respiratory system. These parameters can vary based on whether they...
BACKGROUND
Peak inspiratory and expiratory flows (PIF, PEF) are parameters used to evaluate the mechanics of the respiratory system. These parameters can vary based on whether they are measured using mechanical devices vs. spirometry and based on the barometric pressure at which the measurements are obtained. Our objectives were (1) to report the normal values and variability of PEF and PIF of a Latin American population living at a moderate altitude (2240 m above sea level), (2) to analyze the adjustment of reference values obtained at sea level with those obtained in healthy subjects living at a moderate altitude, and (3) to assess the correlation between PEF obtained by spirometry (PEFs) and PEF obtained by mechanical devices (PEFm).
METHODS
In this prospective and transversal study, men and women with good respiratory health aged between 2.8 and 68 years old were invited to participate. Randomly, they underwent spirometry (to measure PEFs and PIFs) and mechanical flowmetry (to measure PEFm).
RESULTS
A total of 314 subjects participated, with an average age of 24.3 ± 16.4 years; 59% were Women. The main determinants for the reference equations were age, weight, height and sex at birth. The agreement of the PEFm, PEFs and PIFs values was inconsistent with that reported by other authors, even at the same barometric pressure. The association between PEFm and PEFs was r = 0.91 (p < 0.001), and the correlation coefficient of concordance was 0.84.
CONCLUSIONS
The PEFm, PEFs, and PIFs measurements in individuals living at moderate altitudes are different from those found by other authors in cities with different barometric pressures and ethnicities.
Topics: Adolescent; Adult; Aged; Altitude; Child; Child, Preschool; Female; Humans; Latin America; Male; Middle Aged; Peak Expiratory Flow Rate; Prospective Studies; Reference Values; Spirometry; Young Adult
PubMed: 35439986
DOI: 10.1186/s12890-022-01943-x