Peso al nacer en el noroeste argentino. Comparación con una referencia nacional y un estándar internacional / Birth weight in the Northwest region of Argentina. Comparison with a national reference and an international standard

Introducción. El tamaño al nacer se encuentra sujeto a influencias genéticas y ambientales; la altura geográfica es muy influyente. El peso al nacer (PN) es el indicador más utilizado para evaluarlo; existen diferentes estándares y referencias. Debido a la variabilidad de la distribución del PN en relación con la altura en la provincia de Jujuy (Argentina), este trabajo analiza la distribución percentilar del PN para tierras altas (TA) y tierras bajas (TB) jujeñas según edad gestacional (EG) y sexo, y su comparación con una referencia nacional y el estándar internacional INTERGROWTH-21st (IG-21). Población y métodos. Se analizaron los registros de 78 524 nacidos vivos en Jujuy en el período 20092014. Utilizando el método LMS, se estimaron los percentiles 3, 10, 50, 90 y 97 de PN/EG por sexo, para TA (≥2000 msnm), TB (<2000 msnm) y el total provincial, y se compararon gráficamente con la referencia poblacional argentina de Urquía y el estándar IG-21. La significación estadística se determinó mediante la prueba de Wilcoxon. Resultados. El PN en Jujuy presentó distribución heterogénea, con diferencias estadísticamente significativas (p <0,05) entre TB y TA. Al comparar con la referencia nacional y el estándar IG-21, se observaron diferencias por altitud, principalmente en los percentiles 90 y 97 para ambas regiones, y en los percentiles 3 y 10 en TA comparados con el estándar. Conclusiones. Se observó variabilidad de la distribución del PN asociada a la altura geográfica, por lo que, para evaluar el crecimiento intrauterino, resulta fundamental incluir la EG y el contexto donde transcurre la gestación.

Introduction. Size at birth is subject to genetic and environmental influences; altitude is highly influential. Birth weight (BW) is the most widely used indicator to assess size at birth; different standards and references are available. Due to the variability in BW distribution in relation to altitude in the province of Jujuy (Argentina), the purpose of this study is to analyze the percentile distribution of BW in the highlands (HL) and the lowlands (LL) of Jujuy based on gestational age (GA) and sex and compare it with a national reference and the INTERGROWTH-21 st (IG-21) international standard. Population and methods. The records of 78 524 live births in Jujuy in the 2009­2014 period were analyzed. Using the LMS method, the 3 rd, 10 th, 50 th, 90 th, and 97 th percentiles of BW/GA by sex were estimated for the HL (≥ 2000 MASL), the LL (< 2000 MASL), and the total for Jujuy, and compared with the Argentine population reference by Urquía and the IG-21 standard using growth charts. The statistical significance was established using the Wilcoxon test. Results. BW in Jujuy showed a heterogeneous distribution, with statistically significant differences (p < 0.05) between the LL and the HL. When compared with the national reference and the IG-21 standard, differences in terms of altitude were observed, mainly in the 90 th and 97 th percentiles for both regions and the 3 rd and 10 th percentiles in the HL compared with the international standard. Conclusions. BW distribution varied in association with altitude; therefore, to assess intrauterine growth, it is critical to include GA and the environment in which the pregnancy takes place.

First Experience of Plastination at 4150 Meters Above Sea Level, at the Altitude of La Paz, Bolivia / Primera Experiencia de Plastinación a 4150 Metros sobre el Nivel del Mar, en la Altura de La Paz, Bolivia

SUMMARY: Despite attempts to develop the plastination technique in Bolivia, standardized results have not yet been achieved that could be communicated via scientific publications. There is a great deal of misunderstanding around the technique, confusing it with classic techniques of inclusion in different types of resin, such as polyester and epoxy, but these protocols are not plastination. The aim of this work was to communicate the first standardized room-temperature plastination protocol with silicone in Bolivia, with the unique feature of doing so at the altitude of the city of La Paz, thus constituting the first communication of a plastination technique at 4,150 m.a.s.l. sub sede La Paz, La Paz, Bolivia.

En Bolivia, a pesar de los intentos en el desarrollo de la técnica de Plastinación, aún no se han alcanzado resultados estandarizados que pudieran ser comunicados por medio de publicaciones científicas. Existe una gran confusión al momento de desarrollar la técnica, confundiéndola con técnicas clásicas de inclusión en distintos tipos de reina, como poliéster y epoxy, pero no correspondiendo estos protocolos desarrollados a la técnica de plastinación. En este sentido, el objetivo de esta trabajo consistió en comunicar el primer protocolo estandarizado de plastinación a temperatura ambiente con silicona de Bolivia, con la particularidad de desarrollarlo en la altura de la ciudad de La Paz, constituyéndose, de esta manera, en la primera comunicación de una técnica de plastinación a 4.150 metros sobre el nivel del mar.

Potenciales evocados auditivos de tronco en neonatos nacidos a gran altitud / Brainstem auditory evoked potentials in newborn infants born in a high-altitude area

Introducción. Una forma no invasiva y segura de evaluar los parámetros neurofisiológicos en recién nacidos es la evaluación de los potenciales evocados auditivos del tronco encefálico (PEAT). Objetivo. Evaluar las latencias e intervalos de ondas de los PEAT en neonatos sanos nacidos a gran altitud (Cusco, 3399 msnm). Población y métodos. Estudio transversal y prospectivo. Se incluyeron neonatos menores a 14 días de vida, dados de alta a menos de 7 días de nacidos, evaluados para determinar los valores de los PEAT a intensidades sonoras de 70 dB, 80 dB y 90 dB. Se incluyeron las variables edad gestacional, peso al nacer, tipo de parto. Se calcularon las diferencias de las medianas de las latencias e intervalos de las ondas según edad gestacional y peso al nacer. Resultados. Se evaluaron 96 neonatos (17 pretérminos). Las medianas de las latencias de las ondas I a V a 90 dB fueron las siguientes: onda I 1,56 ms; onda II 2,74 ms; onda III 4,37 ms; onda IV 5,62 ms, onda V 6,63 ms. La latencia de la onda I para 80 dB fue de 1,71 ms y para 70 dB de 1,88 ms. Los intervalos para las ondas (I-III), (III-V) y (I-V) fueron de 2,8 ms, 2,2 ms y 5,0 ms respectivamente, sin diferencias entre intensidades (p >0,05). La prematuridad y el bajo peso estuvieron asociados a latencias de la onda I más prolongadas (p <0,05). Conclusiones. Se presentan valores ajustados de latencias e intervalos de los PEAT en neonatos nacidos a gran altitud. Se identificó que, a distintas intensidades sonoras, se ven diferencias en las latencias de las ondas, pero no en los intervalos entre ondas.

Introduction. A non-invasive and safe way to assess neurophysiological parameters in newborn infants is the evaluation of brainstem auditory evoked potentials (BAEPs). Objective. To assess the latencies and wave intervals of BAEPs in healthy newborn infants born in a high-altitude area (Cusco, 3399 MASL). Population and methods. Cross-sectional and prospective study. Newborn infants younger than 14 days of age, discharged less than 7 days after birth, were assessed to determine BAEP values at intensities of 70 dB, 80 dB, and 90 dB. The study variables were gestational age, birth weight, and type of delivery. The median differences in wave latencies and intervals were estimated according to gestational age and birth weight. Results. A total of 96 newborn infants (17 preterm infants) were assessed. The median latencies of waves I­V at 90 dB were for wave I: 1.56 ms, wave II: 2,74 ms, wave III: 4.37 ms, wave IV: 5.62 ms, and wave V: 6.63 ms. The latency of wave I for 80 dB was 1.71 ms and for 70 dB, 1.88 ms. Wave intervals (I­III, III­V, I­V) were 2.8 ms, 2.2 ms, and 5.0 ms, respectively, without differences among intensities (p > 0.05). Prematurity and low birth weight were associated with a longer wave I latency (p < 0.05). Conclusions. Here we describe adjusted BAEP latency and interval values for newborn infants born at high altitude. At different sound intensities, we identified differences in wave latencies, but not in interwave intervals.

Distribución espacial y tendencia secular (1991-2014) de nacidos pequeños para la edad gestacional en Jujuy / Spatial distribution and secular trend (1991­2014) of small for gestational age infants born in Jujuy

Introducción. El feto que no alcanza el potencial de crecimiento esperado en el útero se considera pequeño para la edad gestacional (PEG). Esta restricción depende de factores genéticos y/o ambientales; la altura geográfica es uno muy relevante. Este trabajo analiza la distribución espacial de las prevalencias de PEG y su tendencia secular en Jujuy (1991-2014). Materiales y métodos. Se analizaron los registros de 308 469 nacidos vivos de Jujuy (Dirección de Estadísticas e Información de Salud). Se estimaron prevalencias de PEG (peso/edad gestacional

Introduction. A fetus that does not reach the expected growth potential in utero is considered small for gestational age (SGA). Such restriction depends on genetic and/or environmental factors, being altitude a very relevant factor. This study analyzes the spatial distribution of the prevalence of SGA and its secular trend in Jujuy (1991­2014). Materials and methods. The records of 308 469 live births in Jujuy (Health Statistics and Information Department) were analyzed. The prevalence of SGA (weight/gestational age < P10 and < P3) was estimated for sex according to the INTERGROWTH-21 st standard in the ecoregions of Jujuy (Valle and Ramal ­less than 2000 MASL­, Puna, and Quebrada) across 3 periods (1991­2000, 2001­2009, 2010­2014) and proportions were compared. The secular trend was assessed using the Joinpoint regression analysis. Results. The overall prevalence of SGA was 2.3% (< P3) and 7% (< P10). Significantly higher values were observed in Puna and Quebrada in both SGA categories and across all periods. Only in Valle, significant differences were observed between sexes across all periods. The prevalence of SGA showed a significant downward secular trend at a provincial and regional level, and this was greater in Quebrada (5.2% < P3 and 3.5% < P10). Conclusions. A consistent and significant decrease in the prevalence of SGA has been observed since the 1990s in Jujuy, where altitude is itself a determining factor of size at birth, since the Puna and Quebrada regions showed the highest prevalence of SGA during the entire period.

Fisiología respiratoria. Neumología de altura: saturación de oxígeno, edema pulmonar y pruebas de función pulmonar / Respiratory physiology - High -altitude pneumology: oxygen saturation, pulmonary edema and pulmonary function tests

En las alturas, sobre todo a 2500 metros sobre el nivel del mar, la cantidad absoluta de oxígeno va decreciendo y por lo tanto la cantidad disponible para el intercambio gaseoso disminuye, produciéndose una vasoconstricción hipóxica pulmonar (VHP). La VHP asociada a la hipoxia hipobárica de la altura produce un aumento de la presión pulmonar que es mayor en los lactantes y a mayores alturas. No hay valores únicos de saturación de oxígeno (SatO2) en la altura, porque ésta va disminuyendo según el mayor nivel de altura, aumenta con la edad, y la brecha entre la vigilia y sueño es grande (sobre todo en los primeros meses de vida). El 25% de los niños sanos que viven en altura tienen valores de SatO2 significativamente menores que el 75% restante. Los valores normales de los índices de apnea/hipopnea son distintos a los de nivel del mar. El edema pulmonar de las alturas es una patología frecuente, que se produce por un incremento desproporcionado en la VHP reflejando una hiperactividad del lecho vascular pulmonar ante la exposición aguda a la hipoxia hipobárica. Tiene cuatro fenotipos, es infrecuente en menores de 5 años y rara vez es mortal, la sospecha clínica y el manejo oportuno con oxigeno es la clave. Finalmente, en la altura los valores normales de la función pulmonar de la espirometría, oscilometría de impulso y capacidad de difusión son distintos que a nivel del mar.

At high altitude, especially > 2,500 meters above sea level, the absolute amount of oxygen decreases and therefore the amount available for gas exchange decreases, producing hypoxic pulmonary vasoconstriction (VHP). VHP associated with high-altitude hypobaric hypoxia produces an increase in pulmonary pressure that is greater in infants and at higher altitudes. There are no single values of oxygen saturation (SatO2) at altitude, because it decreases with the highest level of altitude, increases with age, and the gap between wakefulness and sleep is large (especially in the first months of life). Around 25% of healthy children living at altitude have SatO2 values significantly lower than the remaining 75%. The normal values of the apnea/hypopnea indices are different from those at sea level. High altitude pulmonary edema is a frequent pathology that is produced by a disproportionate increase in VHP reflecting hyperactivity of the pulmonary vascular bed in the face of acute exposure to hypobaric hypoxia, it has four phenotypes, it is uncommon in children under 5 years of age, and it is rarely fatal, the clinical suspicion and timely management with oxygen is the key. Finally, at high altitude, the normal values of lung function from spirometry, impulse oscillometry, and diffusing capacity are different from those at sea level.

Bloodletting Acupuncture at Jing-Well Points Alleviates Myocardial Injury in Acute Altitude Hypoxic Rats by Activating HIF-1α/BNIP3 Signaling-Mediated Mitochondrial Autophagy and Decreasing Oxidative Stress / 中国结合医学杂志

OBJECTIVE@#To explore the protective effect and possible mechanisms of bloodletting acupuncture at Jing-well points (BAJP) pre-treatment on acute hypobaric hypoxia (AHH)-induced myocardium injury rat.@*METHODS@#Seventy-five rats were randomly divided into 5 groups by a random number table: a control group (n=15), a model group (n=15), a BAJP group (n=15), a BAJP+3-methyladenine (3-MA) group (n=15), and a BANA (bloodletting at nonacupoint; tail bleeding, n=15) group. Except for the control group, the AHH rat model was established in the other groups, and the corresponding treatment methods were adopted. Enzyme-linked immunosorbent assay (ELISA) was used to detect creatine kinase isoenzyme MB (CK-MB) and cardiac troponins I (CTnI) levels in serum and superoxide dismutase (SOD) and malondialdehyde (MDA) levels in myocardial tissue. Hematoxylin-eosin (HE) staining was used to observe myocardial injury, and terminal deoxynucleotidyltransferase-mediated dUTP-biotin nick end labeling (TUNEL) staining was used to observe cell apoptosis. Transmission electron microscopy detection was used to observe mitochondrial damage and autophagosomes in the myocardium. The mitochondrial membrane potential of the myocardium was analyzed with the fluorescent dye JC-1. Mitochondrial respiratory chain complex (complex I, III, and IV) activities and ATPase in the myocardium were detected by mitochondrial respiratory chain complex assay kits. Western blot analysis was used to detect the autophagy index and hypoxia inducible factor-1α (HIF-1α)/Bcl-2 and adenovirus E1B 19k Da-interacting protein 3 (BNIP3) signaling.@*RESULTS@#BAJP reduced myocardial injury and inhibited myocardial cell apoptosis in AHH rats. BAJP pretreatment decreased MDA levels and increased SOD levels in AHH rats (all P<0.01). Moreover, BAJP pretreatment increased the mitochondrial membrane potential (P<0.01), mitochondrial respiratory chain complex (complexes I, III, and IV) activities (P<0.01), and mitochondrial ATPase activity in AHH rats (P<0.05). The results from electron microscopy demonstrated that BAJP pretreatment improved mitochondrial swelling and increased the autophagosome number in the myocardium of AHH rats. In addition, BAJP pretreatment activated the HIF-1α/BNIP3 pathway and autophagy. Finally, the results of using 3-MA to inhibit autophagy in BAJP-treated AHH rats showed that suppression of autophagy attenuated the treatment effects of BAJP in AHH rats, further proving that autophagy constitutes a potential target for BAJP treatment of AHH.@*CONCLUSION@#BAJP is an effective treatment for AHH-induced myocardial injury, and the mechanism might involve increasing HIF-1α/BNIP3 signaling-mediated autophagy and decreasing oxidative stress.

Treatment of spinal burst fractures with pedicle screw fixation at high altitude area / 中国骨伤

OBJECTIVE@#According to the characteristics of spinal burst fractures in high-altitude areas and the local medical conditions, to explore the clinical efficacy of short-segment fixation with pedicle screws combined with screw placement in injured vertebrae in the treatment of thoracolumbar burst fractures.@*METHODS@#From August 2018 to December 2021, 12 patients with single-vertebral thoracolumbar burst fractures without neurological symptoms were treated with injured vertebral screw placement technique, including 7 males and 5 females;aged 29 to 54 years old, with an average of(42.50±7.95) years old;6 cases of traffic accident injury, 4 cases of high fall injury, 2 cases of heavy object injury;2 cases of T11, 4 cases of T12, 3 cases of L1, 2 cases of L2, and 1 case of L3. In the operation, screws were first placed in the upper and lower vertebrae of the fracture, pedicle screws were placed in the injured vertebra, and connecting rods were installed, and the fractured vertebral body was reset by positioning and distraction. Visual analogue scale (VAS) and Japanese Orthopedic Association (JOA) scoring were used to evaluate the changes in pain and quality of life of patients, and the kyphotic correction rate and correction loss rate of the injured segment were measured by X-ray.@*RESULTS@#All operations were successful without significant intraoperative complications. All 12 patients were followed up, the duration ranged from 9 to 27 months, with an mean of (17.75±5.79) months. VAS at 3 days after operation was significantly higher than that at admission (t=6.701, P=0.000). There was significant difference in JOA score between 9 months after operation and at admission (t=5.085, P=0.000). Three days after operation, Cobb angle was (4.42±1.16)°, and the correction rate was (82±5)% compared with (25.67±5.71)° at admission. Cobb angle was (5.08±1.24) °at 9 months after operation, with a corrected loss rate of (16±13)%. No loosening or breakage of internal fixation was found.@*CONCLUSION@#Under the high-altitude hypobaric and hypoxic environment, the effect of the operation should be ensured while reducing the trauma. The application of the technique of placing screws on the injured vertebra can effectively restore and maintain the height of the injured vertebra, with less bleeding and shorter fixed segments, which is an effective method.

Factors affecting pulmonary arterial pressure in response to high-altitude hypoxic stress / 生理学报

The alteration of pulmonary artery pressure is an important physiological indicator to reflect the organism's adaptation to acclimatization or the pathological injury in response to high-altitude hypoxic environment. The effects of hypoxic stress at different altitudes for different time on pulmonary artery pressure are different. There are many factors involved in the changes of pulmonary artery pressure, such as the contraction of pulmonary arterial smooth muscle, hemodynamic changes, abnormal regulation of vascular activity and abnormal changes of cardiopulmonary function. Understanding of the regulatory factors of pulmonary artery pressure in hypoxic environment is crucial in clarifying the relevant mechanisms of hypoxic adaptation, acclimatization, prevention, diagnosis, treatment and prognosis of acute and chronic high-altitude diseases. In recent years, great progress has been made in the study regarding the factors affecting pulmonary artery pressure in response to high-altitude hypoxic stress. In this review, we discuss the regulatory factors and intervention measures of pulmonary arterial hypertension induced by hypoxia from the aspects of hemodynamics of circulatory system, vasoactive state and changes of cardiopulmonary function.

Responses of blood parameters and hemoglobin subtypes in plateau zokors and plateau pikas to different altitude habitats / 生理学报

The plateau zokor (Myospalax baileyi) and plateau pika (Ochotona curzoniae) are native species unique to the Qinghai-Tibetan Plateau with successful adaptation to the hypoxic environment. In this study, the number of red blood cells, hemoglobin concentration, mean hematocrit and mean volume of red blood cells were measured in plateau zokors and plateau pikas at different altitudes. Hemoglobin subtypes of two plateau animals were identified by mass spectrometry sequencing. The forward selection sites in two animals' hemoglobin subunits were analyzed by PAML4.8 program. Homologous modeling was used to analyze the effect of forward selection sites on the affinity of hemoglobin to oxygen. The adapting strategies of plateau zokors and plateau pikas to hypoxia at different altitudes were analyzed through comparing blood parameters between the two species. The results indicated that, with increasing altitudes, plateau zokors responded to hypoxia by increasing red blood cell count and decreasing red blood cell volume, while plateau pikas took the opposite strategies to plateau zokors. In erythrocytes of plateau pikas, both adult α2β2 and fetal α2ε2 hemoglobins were identified, while erythrocytes of plateau zokors only had adult α2β2 hemoglobin, however the affinities and the allosteric effects of the hemoglobin of plateau zokors were significantly higher than those of plateau pikas. Mechanistically, in the α and β subunits of hemoglobin of plateau zokors and pikas, the numbers and the sites of the positively selected amino acids as well as the side chain groups polarities and orientations of the amino acids differed significantly, which may result in the difference of the affinities to oxygen of hemoglobin between plateau zokors and pikas. In conclusion, the adaptive mechanisms to respond to hypoxia in blood properties of plateau zokors and plateau pikas are species-specific.

Associations between glycated hemoglobin and glucose indicators in adults in areas at different altitude in China / 中华流行病学杂志

Objective: To explore the associations of glycated hemoglobin (HbA1c) with FPG and oral glucose tolerance test 2-hour (OGTT-2 h) in areas at different altitude in China. Methods: Subjects who participated in 2018-2019 China Chronic Disease and Risk Factor Surveillance and had no prior type 2 diabetes diagnosis were included. Subsequently, they were categorized into three groups based on altitude of living area (<2 000, 2 000- and ≥3 000 m). With adjustment for intracluster correlation, multivariable linear regression analysis was performed to evaluate the associations of HbA1c with FPG and OGTT-2 h in the context of HbA1c was normal (<5.7%) or abnormal (≥5.7%). Furthermore, the shape of relationships between HbA1c and glucose indicators was examined using restricted cubic spline. Finally, receiver operating characteristic curve was used to evaluate the diagnostic performance of HbA1c for diabetes. Results: A total of 157 277 subjects were included in the analysis. While FPG and OGTT-2 h levels gradually decreased with increase of altitude, HbA1c level was similar among the three groups. When HbA1c was <5.7%, its association with FPG and OGTT-2 h was weak and no obvious difference was observed among the three groups. When HbA1c was ≥5.7%, the FPG and OGTT-2 h increased by 15.45% (95%CI:14.71%- 16.18%) and 24.54% (95%CI:23.18%-25.91%) respectively per one standard deviation increase in HbA1c in group in area at altitude <2 000 m. However, the FPG and OGTT-2 h increased by 13.08% (95%CI:10.46%-15.76%) and 21.72% (95%CI:16.39%-27.31%), respectively, in group in area at altitude 2 000- m, and increased by 11.41% (95%CI:9.32%-13.53%) and 20.03% (95%CI:15.38%- 24.86%), respectively, in group of altitude ≥3 000 m. The restricted cubic spline indicated that the curve showing the association of HbA1c with FPG and OGTT-2 h was flat when HbA1c was <5.7%, but showed a positive linear relationship when HbA1c was ≥5.7%. The area under curve for detecting diabetes was 0.808 (95%CI:0.803-0.812) in group of altitude <2 000 m and 0.728 (95%CI:0.660-0.796, P=0.022) in group of altitude ≥3 000 m. The relevant optimal cutoff value of HbA1c was 5.7%, with a sensitivity of 65.4% and a specificity of 83.0%, and 6.0%, with a sensitivity of 48.3% and a specificity of 93.7%, respectively. Conclusions: When HbA1c was ≥5.7%, the association between HbA1c and glucose indicators became weaker as the increase of altitude. In the area at altitude ≥3 000 m, it may not be appropriate to use HbA1c in the diagnosis of diabetes.

Analysis on echocardiographic data of fetal heart defects at high altitude in Yunnan province and surrounding high altitude areas / 中华心血管病杂志

Objective: To explore the current situation of fetal heart defects in Yunnan Province and surrounding high altitude areas and the social factors affecting pregnancy outcome. Methods: This is a retrospective study. Pregnant woman who underwent fetal echocardiography and diagnosed as fetal cardiac defects in Yunnan Fuwai Cardiovascular Hospital from June 2017 to January 2021 were included. According to the clinical prognostic risk scoring system and grading criteria of fetal cardiac birth defects, the cases were divided into grade Ⅰ to Ⅳ. The disease distribution and proportion of each prognostic grade, pregnancy outcomes were analyzed and compared. The cases were divided into continued pregnancy group and terminated pregnancy group according to pregnancy outcome. The social factors that may affect the selection of pregnancy outcomes were analyzed by multivariate logistic regression analysis. Results: A total of 4 929 fetal echocardiography examination data were collected, and 4 464 cases (90.57%) were from Yunnan Province and surrounding high altitude areas. 2 166 cases of heart defects were finally analyzed, including 998 cases of congenital heart disease (CHD), 93 cases of cardiac tumors, cardiomyopathy and arrhythmia, 1 075 cases of foramen ovale, ductus arteriosus abnormalities and normal variations. The pregnant women were (29.2±5.0) years old with (25.6±3.8) gestational weeks. The number of cases with prognostic grade from Ⅰ to Ⅳ was 1 037 (47.88%), 620 (28.62%), 314 (14.50%), and 44 (2.03%), respectively. And 151 cases (6.97%) were not classified. The cases of normal variation and thin aortic arch development accounted for 42.66% (924/2 166), 5.22% (113/2 166), respectively. The top 3 diseases of grade Ⅱ were ventricular septal defect, coarctation of aorta and mild-moderate pulmonary stenosis, respectively, and their distribution was 11.63% (252/2 166), 3.92% (85/2 166) and 2.35% (51/2 166) respectively in all cases of heart defects, and 25.25% (252/998), 8.52% (85/998) and 5.11% (51/998) respectively in cases of CHD. Among the cases rated as grade Ⅲ and Ⅳ, most of them were complicated congenital heart disease, and the disease types are scattered. The more common cases in grade Ⅲ were complete transposition of great arteries (accounting for 2.40% (52/2 166) of all cases with heart defects, 5.21% (52/998) of all cases with CHD) and pulmonary artery occlusion (type Ⅰ to Ⅲ) with ventricular septal defect (accounting for 2.17% (47/2 166) of all cases with heart defects, and 4.71% (47/998) of all cases with CHD). In grade Ⅳ, single ventricle (0.74% (16/2 166) of all cases with heart defects, 1.60% (16/998) of all cases with CHD) and left ventricular dysplasia syndrome (0.65% (14/2 166) of all cases with heart defects, 1.40% (14/998) of all cases with CHD) are more common. A total of 1 084 cases were successfully followed up, and 675 cases were born, 392 cases were terminated, spontaneous abortion occurred in 17 cases. The proportion of terminated pregnancy cases was significantly increased from grade Ⅰ to Ⅳ, accounting for 5.24% (21/401), 27.78% (70/252), 89.54% (214/239) and 95.56% (43/45), respectively. Among the terminated pregnancy cases, those with grade Ⅲ accounted for the highest proportion (54.59% (214/392)). The distribution of terminated pregnancy cases was mainly complex congenital malformations or diseases with very poor prognosis (pregnancy outcome grade Ⅲ and Ⅳ), and proportion of terminated pregnancy with pregnancy outcome grade Ⅰ and Ⅱ cases (normal variation or good prognosis) accounted for 5.36% (21/392) and 17.86% (70/392), respectively. The results of multivariate logistic regression analysis showed that pregnant women with low education (high school and below: OR=2.73, 95%CI 1.26-5.93, P<0.001; illiteracy: OR=3.27, 95%CI 1.29-7.10, P<0.001) and low family income (Annual income<100 000 yuan: OR=2.47, 95%CI 1.69-5.12, P<0.001) were more likely to choose termination of pregnancy in case of fetal heart defect. Conclusion: In Yunnan province and the surrounding high altitude areas, the disease distribution of fetal heart defect is mainly simple or low-risk disease, but the complex malformation, especially the disease with poor pregnancy outcome, accounts for a relative high proportion. Pregnancy termination also occurs in some cases with good pregnancy outcome. The education level and family income of pregnant women may affect their choice of pregnancy outcome in case of fetal heart defect.

Male reproductive system and simulated high-altitude environment: preliminary results in rats / 亚洲男科学杂志(英文版)

This study assessed the effects of a simulated high-altitude environment on the reproductive system of prepubertal male rats and the reversibility of these effects upon return to a normal environment. Three-week-old male Wistar rats were randomly allocated to 4 groups that were exposed to different conditions: a normal environment for 6 weeks and 12 weeks, respectively, hypobaric hypoxia for 6 weeks, and hypobaric hypoxia for 6 weeks followed by a normal environment for 6 weeks. Multiple pathophysiological parameters were evaluated at the histological, endocrine, and molecular levels. Hypobaric hypoxia exposure for 6 weeks during the prepubertal phase significantly altered physiological parameters, body functions, blood indices, and reproductive potential. Six weeks after returning to a normal environment, the damaged reproductive functions partially recovered due to compensatory mechanisms. However, several changes were not reversed after returning to a normal environment for 6 weeks, including disorders of body development and metabolism, increased red blood cells, increased fasting blood glucose, abnormal blood lipid metabolism, decreased testicular and epididymis weights, abnormal reproductive hormone levels, excessive apoptosis of reproductive cells, and decreased sperm concentration. In summary, a hypobaric hypoxic environment significantly impaired the reproductive function of prepubertal male rats, and a return to normal conditions during the postpubertal phase did not fully recover these impairments.

Clinical effect of Kirschner wire intramedullary fixation in the treatment of pediatric both-bone forearm fractures at high altitude area / 中国骨伤

OBJECTIVE@#To explore the clinical effect of Kirschner wire intramedullary fixation in the treatment of both-bone forearm fractures in children of high altitude area.@*METHODS@#From August 2020 to December 2021, 19 children were treated with Kirschner wire intramedullary fixation including 11 males and 8 females, aged from 4 to 13 years old with an average of (8.16±2.71) years old. The course of disease was 1 to 10 days, with a mean of (4.11±2.51) d. First, close reduction was performed. If the reduction was unsuccessful, limited open reduction was performed, followed by Kirschner wire intramedullary fixation of the radius and ulna. The fracture healing was evaluated by X-ray after operation, and the curative effect was evaluated by Anderson forearm function score standard.@*RESULTS@#The wound healed well after operation, 2 cases had clinical manifestations of needle tail irritation after operation, and the symptoms disappeared after removing the internal fixation. The average follow-up time was(7.68±3.50) months (3 to 14 months). X-ray showed that all fracture healing in follow-up, Anderson forearm function score showed excellent in 16 cases, good in 2 cases and fair in 1 case at the final follow-up.@*CONCLUSION@#Children with fractures in plateau areas often have delayed medical treatment, lack of medical conditions and insufficient compliance. Based on these characteristics, Kirschner wire intramedullary fixation for the treatment of children's double forearm fractures has the advantages of small injury and rapid recovery. It is a kind of operation method that can be popularized.

Calidad de medición en investigación científica en contexto de gran altitud: a nivel atómico análisis estudio de interlaboratorios, oxido de deuterio por FTIR ­ 2021 / Quality of measurement in scientific research in a high-altitude context: at the atomic level interlaboratory study analysis, deuterium oxide by FTIR ­ 2021

Se presenta conceptos del saber hacer investigación científica asociada a la calidad de las mediciones, y dentro de ella sobre la calidad intrínseca de la medición de variables, dirigida a dos condiciones de la misma: la precisión y exactitud. Se describe formas de evaluación de la precisión como ser el coeficiente de variación y el error técnico de las mediciones. Por otro lado se describe formas de evaluación de la exactitud como son la regresión linear y el puntaje Z. También se sugieren y se describen las acciones y las herramientas para mejorar tanto la precisión como la exactitud. El análisis de agua enriquecida con oxido de deuterio, es una temática que fue tomada en cuenta por la Agencia Internacional de Energía Atómica (IAEA), Viena, Austria, en la gestión 2021, y se organizó una actividad mediante el "Estudio de Interlaboratorios, Oxido de Deuterio por FTIR ­ 2021". El propósito fue asegurar la calidad integral en la capacidad construida en el uso de técnicas de isotopos estables para la evaluación del estado de salud y nutricional. Así mismo, evaluar la calidad de medición de la exactitud relativa sobre el enriquecimiento del agua con óxido de deuterio en 43 laboratorios a nivel internacional, grupo en cual se incluyó al Laboratorio de Biología Atómica (LABA) de la Unidad de Crecimiento y Desarrollo (UCREDE). Se utilizó la regresión linear y el puntaje Z para evaluar la exactitud. Se concluye que los resultados demostraron un muy buen rendimiento en exactitud relativa con los equipos FTIR que midieron el enriquecimiento de deuterio en muestras de agua.

Concepts of knowing how to do scientific research associated with the quality of measurements are presented, and within it on the intrinsic quality of the measurement of variables, aimed at two conditions of the same: precision and accuracy. Forms of precision evaluation are described, such as the coefficient of variation and the technical error of the measurements. On the other hand, forms of accuracy evaluation are described, such as linear regression and Z-score. Actions and tools to improve both precision and accuracy are also suggested and described. The analysis of water enriched with deuterium oxide is a topic that was taken into account by the International Atomic Energy Agency (IAEA), Vienna, Austria, in the 2021 management, and an activity was organized through the Interlaboratory Study, Deuterium Oxide by FTIR ­ 2021. The purpose was to ensure comprehensive quality in the capacity built in the use of stable isotope techniques for the evaluation of health and nutritional status. Likewise, to evaluate the quality of measurement of the relative accuracy of the enrichment of water with deuterium oxide in 43 laboratories at the international level, a group that included the Atomic Biology Laboratory (LABA) of the Growth and Development Unit (UCREDE ). Linear regression and Z-score were used to assess accuracy. It is concluded that the results demonstrated a very good performance in relative accuracy with the FTIR equipment that measured deuterium enrichment in water samples.

Efectos biológicos de la exposición a distintas concentraciones de oxígeno: desde la hipoxia hipobárica al oxígeno hiperbárico / Biological effects due to exposure to different concentrations of oxygen from hypo to hyperoxemia

The systemic effects of oxygen deficiency or excess are not thoroughly described. Knowledge is evolving towards the description of beneficial and detrimental effects of both extremes of partial pressure of oxygen (PaO2). The cellular and tissue mediators derived from the modulation of the oxidative tone and the production of reactive oxygen species (ROS) are widely characterized biochemically, but the pathophysiological characterization is lacking. Preclinical models support the use of hypobaric hypoxia preconditioning, based on its beneficial effects on ventricular function or its reduction in infarct size. A very important use of oxygen today is in commercial diving. However, novel clinical indications for oxygen such as the healing of diabetic foot ulcers and bone injury caused by radiotherapy are increasingly used. On the other hand, the modulation of the hypoxic response associated with exposure to high altitude environments (hypobaric), favors Chile and its highlands as a natural laboratory to determine certain cardiovascular, cerebral and metabolic responses in the resident population. Also, the consequences of the intermittent exposure to high altitudes in workers also deserves attention. This review discusses the physiopathological response to hypo and hyperoxemia, associated with environments with different oxygen concentrations, and brings back the concept of oxygen as a pharmacological mediator in extreme environments such as high altitudes and hyperbaric medicine in divers, decompression sickness, osteonecrosis associated with radiotherapy and sudden sensorineural hearing loss.

Effect of Chronic Altitude Hypoxia on Redox Balance in Preadolescents and Adolescents / Efectos de la hipoxia altitudinal crónica sobre el balance Redox de preadolescentes y adolescentes / Efeito da exposição crônica à hipóxia de altitude no equilíbrio oxidante/antioxidante de crianças e adolescentes

Living at high altitude increases oxidative stress. Likewise, growth and maturation during adolescence can increase levels of reactive oxygen species (ros). Changes in redox profiles have been evaluated in adults living at high altitudes; however, there are no studies on these changes in peripubertal populations living at moderate altitudes, we determine how living at moderate altitude affects the oxidative and inflammatory status of healthy preadolescents and adolescents. Materials and Methods: A cross-sectional study was conducted in healthy male Colombian preadolescents and adoles-cents (9­18 years old, Tanner scale classification) who lived at low altitude (n = 26) or moderate altitude (n = 26). Plasma oxidative and inflammatory status was assessed via spectrophotometry. Oxidative markers included malondialdehyde, 4-hydroxy-trans-2-nonenal, and carbonyl groups. Antioxidant markers included total antioxidant status, glutathione, catalase, superoxide dismutase, uric acid, and thiols. Inflammatory markers included interleukins-1, -6, and -10 and tumor necrosis factor. Results:Only uric acid levels were higher in adolescents (5.34 and 5.66 mg/dl) compared to preadolescents (3.85 and 4.07 mg/dl) in both moderate and low altitude groups, respectively. Participants who lived at mod-erate altitude presented significantly higher levels of malondialdehyde (4.82 and 3.73 nM/mg protein) and lower level of glutathione and thiols (1.21 and 1.26 µmol/mg protein) than in those at low altitude. Their inflammatory profiles did not differ. Conclusion: Oxidant profiles increased in peripubertal popu-lations residing at moderate altitude; this could be owing to antioxidant consumption by ros and active metabolism during puberty.

vivir en altura es un factor que se asocia con el estrés oxidativo. El crecimiento y la maduración pueden ser un estresor adicional. Es insuficiente la evidencia sobre alteraciones del perfil redox en peripúberes residentes a altitudes moderadas. El propósito fue establecer el efecto de vivir en una altitud moderada sobre el perfil redox e inflamatorio en preadolescentes y adolescentes sanos. Materiales y métodos: estudio transversal en varones preadolescentes y adolescentes sanos (9-18 años) que viven en altitud baja (n = 26) o altitud moderada (n = 26). El estado oxidativo plasmático se evaluó mediante espectrofotometría a través de marcadores de oxidación (malondialdehído e hidroxinonenal y grupos carbonilo) y antioxidantes (estado antioxidante total, glutatión, catalasa, superóxido dismutasa, ácido úrico y tioles). El perfil inflamatorio se midió con interleucinas 1, 6, 10 y factor de necrosis tumoral α. Resultados: solo el ácido úrico fue diferente entre adolescentes (5.34 y 5.66 mg/dl para moderada y baja altitud, respectivamente) y preadolescentes (3.85 y 4.07 mg/dl para moderada y baja altitud, res-pectivamente). El grupo de preadolescentes y adolescentes de moderada altitud presentó niveles más altos de malondialdehído (4.82 y 3.73 nM/mg de proteína, respectivamente) y menor glutatión y tioles (1.21 y 1.26 µmol/mg de proteína), en comparación con sus contrapartes de baja altitud. Conclusión: las poblaciones peripúberes que residen en una altitud moderada presentan un perfil oxidante más alto, lo que puede estar relacionado con la depleción de antioxidantes, por una mayor producción de especies reactivas de oxígeno relacionada con la hipoxia y el metabolismo activo de la pubertad.

viver em grandes altitudes é um fator de estresse associado ao estresse oxidativo. Durante a adolescência, os processos de crescimento e maturação podem aumentar as espécies reativas de oxi-gênio. Alterações no perfil redox foram estudadas em adultos expostos a grandes altitudes, mas não em populações peripubertais vivendo em altitudes moderadas. Nosso objetivo é estabelecer o efeito de viver em uma altitude moderada sobre o estado oxidativo e inflamatório em pré-adolescentes e adolescentes saudáveis. Materiais and métodos: foi realizado um estudo transversal em pré-adolescentes e adolescen-tes colombianos saudáveis (9-18 anos, na escala de classificação de Tanner) que viviam em baixa altitude (n = 26) ou altitude moderada (n = 26). O estado oxidativo e inflamatório do plasma foi avaliado por espectrofotometria: 1) Marcadores de oxidação: grupos Malondialdeído + 4-hidroxi-trans-2-nonenal e carbonila; 2) antioxidantes: estado antioxidante total, glutationa, catalase, superóxido dismutase, ácido úrico e tióis; 3) Marcadores de inflamação: interleucinas 1, 6, 10 e fator de necrose tumoral α. Resultados:apenas o ácido úrico foi maior em adolescentes (5,34 e 5,66 mg/dl) em comparação com pré-adolescentes (3,85 e 4,07 mg/dl) dos grupos de altitude moderada e baixa, respectivamente. A altitude moderada apre-sentou níveis significativamente maiores de Malondialdeído (4,82 e 3,73 nM/mg de proteína), e menores níveis de Glutationa e tióis (1,21 e 1,26 µmol/mg de proteína), em comparação com a baixa altitude. Nenhuma diferença foi detectada no perfil inflamatório. Conclusão: as populações peripubertais que residem em altitude moderada apresentam maior perfil oxidante, o que pode estar relacionado ao con-sumo de antioxidantes devido à maior produção de ros relacionada à hipóxia e ao metabolismo ativo por volta da puberdade.

Maltrato en la gestante adolescente y su efecto en el peso del recién nacido en la altura geográfica peruana, Huancayo, Perú / Abuse in adolescent pregnant women and its effect on newborn weight in the Peruvian geographical altitude, Huancayo, Peru

INTRODUCCIÓN: La violencia en la gestante está asociada a muchos factores del recién nacido, pero esto casi no se ha reportado en la altura geográfica. OBJETIVO: Determinar si existe asociación entre el maltrato en la gestante adolescente y su efecto en el peso del recién nacido en la altura geográfica peruana. MÉTODO: Estudio de cohorte retrospectiva. Se tomó la información de 855 gestantes. La variable exposición fue que hubieran sufrido violencia, lo cual se asoció al peso y otros datos del recién nacido en la ciudad de Huancayo, Perú. RESULTADOS: Según el análisis multivariado, hubo más riesgo de que el niño tuviera un peso inadecuado cuando hubo violencia física (riesgo relativo ajustado [RRa]: 1,42; intervalo de confianza del 95% [IC95%]: 1,01-2,00; p = 0,045), cuando se tuvo un parto pretérmino según Capurro (RRa: 4,90; IC95%: 2,85-8,45; p < 0,001), cuando hubo complicaciones en el parto (RRa: 2,11; IC95%: 1,25-3,61; p = 0,006) y si el abuso inició en el primer trimestre (RRa: 14,74; IC95%: 4,70-46,27; p < 0,001), el segundo (RRa: 18,72; IC95%: 5,78-60,63; p < 0,001) o el tercero (RRa: 18,87; IC95%: 4,71-75,60; p < 0,001). CONCLUSIONES: Existe asociación entre sufrir violencia física durante la gestación y el bajo peso al nacer, y también se encontró asociación con otras variables.

INTRODUCTION: Violence in the pregnant woman is associated with many newborn factors, but this has hardly been reported in the geographical altitude. OBJECTIVE: To determine whether there is an association between adolescent pregnancy abuse and its effect on newborn birth weight in high altitude Peru. METHOD: Retrospective cohort study. Information was taken from 855 pregnant women. The exposure variable was whether they had suffered gender-based violence, the exposure variable was that they had suffered violence, which was associated with the weight and other data of the newborn in Huancayo city, Peru. RESULTS: In the multivariatee analysis it was found that there was a higher risk of the child having an inadequate weight when there was physical violence (adjusted relative risk [RRa]: 1.42; 95% confidence interval [95% CI]: 1.01-2.00; p = 0.045), when there was a preterm birth according to Capurro (RRa: 4.90; 95% CI: 2.85-8.45; p < 0.001), when there were complications in childbirth (RRa: 2.11; 95% CI: 1.25-3.61; p = 0.006) and if the abuse started in the first trimester (RRa: 14.74; 95% CI: 4.70-46.27; p < 0.001), second (RRa: 18.72; 95% CI: 5.78-60.63; p < 0.001) or third (RRa: 18.87; 95% CI: 4.71-75.60; p < 0.001). CONCLUSIONS: There is an association between suffering physical violence during gestation and low birth weight, and association was also found with other variables.

Factores de riesgo de ingreso a unidad de cuidados intensivos o mortalidad en adultos hospitalizados por COVID-19 en altura / Risk factors for intensive care unit admission or mortality in adults hospitalized for COVID-19 at high altitude

RESUMEN Objetivo. Determinar los factores de riesgo de ingreso a unidad de cuidados intensivos (UCI) o mortalidad en pacientes hospitalizados por COVID-19 en un hospital de Puno, Perú. Materiales y métodos. Estudio de cohorte retrospectivo en adultos hospitalizados entre abril y diciembre del 2020. Se evaluaron características sociodemográficas, funciones vitales, comorbilidades, tratamiento recibido y su asociación con el ingreso a UCI o mortalidad (desenlace adverso). Se utilizó regresión de Poisson con varianza robusta para calcular riesgos relativos (RR) crudos y ajustados con sus intervalos de confianza al 95% (IC95%). Resultados. Se analizaron 348 historias clínicas. La mediana de edad en años fue 42,5 (RIC: 30,0; 58,0); el 38,2% fueron varones, y el 35,3% falleció o ingresó a UCI. Los que ingresaron con una saturación de oxígeno ≤ 75%, tuvieron 2,79 veces la probabilidad de tener el desenlace adverso (p < 0,001), en comparación con los que ingresaron con una saturación ≥ 85%; los que ingresaron con un valor entre 75-79% tuvieron 2,92 veces la probabilidad de tener el desenlace adverso (p < 0,001); asimismo, los que ingresaron con saturación entre 80-84% tuvieron 1,70 veces la probabilidad de presentar el desenlace adverso; sin embargo la diferencia no fue estadísticamente significativa (p=0,066). Además, hubo mayor riesgo de desenlace adverso en pacientes de sexo masculino RR= 1,75 (p<0,001), edad > 40 años RR 3,5 (p=0,001), taquipnea RR=1,66 (p=0,010), o con diabetes, RR = 1,53 (p=0,011). Conclusiones . Los factores de riesgo para ingresar a UCI o mortalidad por COVID-19 fueron el sexo masculino, edad mayor de 40 años, saturación baja, diabetes y taquipnea.

ABSTRACT Objective. To determine the risk factors for admission to the intensive care unit (ICU) or mortality in patients hospitalized for COVID-19 in a hospital in Puno, Peru. Materials and methods. Retrospective cohort study in adults hospitalized between April and December 2020. We evaluated Sociodemographic characteristics, vital functions, comorbidities, treatment received and its association with admission to ICU or mortality (adverse outcome). Poisson regression with robust variance was used to calculate crude and adjusted relative risks (RR) with their 95% confidence intervals (95%CI). Results. A total of 348 medical records were analyzed. The median age in years was 42.5 (IQR: 30.0; 58.0); 38.2% were male, and 35.3% died or were admitted to the ICU. Those admitted with an oxygen saturation ≤ 75% were 2.79 times more likely to have the adverse outcome (p < 0.001), compared to those admitted with a saturation ≥ 85%; those admitted with a value between 75-79% were 2.92 times more likely to have the adverse outcome (p < 0.001); likewise, those admitted with saturation between 80-84% were 1.70 times more likely to have the adverse outcome; however, the difference was not statistically significant (p=0.066). In addition, male patients, RR= 1.75 (p<0.001); those aged > 40 years, RR 3.5 (p=0.001); those with tachypnea, RR=1.66 (p=0.010); or with diabetes, RR = 1.53 (p=0.011) had higher risk of presenting the adverse outcome. Conclusions. The risk factors for ICU admission or mortality due to COVID-19 were male sex, age over 40 years, low saturation, diabetes and tachypnea.

Oxygen use in Atacama large millimeter and submillimeter (ALMA) arrays in Chajnantor valley at 5050 m / Uso de oxígeno en Atacama large millimeter and submillimeter (ALMA) en el valle de Chajnantor a 5050 m

The Chilean workforce has over 200,000 people that are intermittently exposed to altitudes over 4000 m. In 2012, the Ministry of Health provided a technical guide for high altitude workers that included a series of actions to mitigate the effects of hypoxia. Previous studies have shown the positive effect of oxygen enrichment at high altitudes. The Atacama Large Millimeter / submillimeter Arrays (ALMA) radiotelescope operate at 5,050 m (Array Operation Site, AOS) and is the only place in the world where Pressure Swing Adsorption (PSA) and Liquid Oxygen technologies have been installed at a large scale. Here we discuss our experience using oxygen supplementation at ALMA, to prevent the malaise and/or risks associated with exposure at 5,050 m. Antenna operators experienced chronic intermittent hypobaric hypoxia (CIHH, shiftwork 8 days HA*6 days rest SL) over 4 years. Studies to define normal O2 saturation values were performed in OSF and AOS by continuous recording during the shift. The outcomes showed no differences between production procedures (PSA or Liquid oxygen) in regulating oxygen availability at AOS facilities. As a result, big-scale installations have difficulties reaching the appropriate oxygen concentration due to leaks in high mobility areas. In addition, the PSA plant requires adequation and maintenance to operate at a very high altitude.

La fuerza laboral chilena cuenta con más de 200.000 personas que están expuestas intermitentemente a altitudes superiores a los 4000 m. En 2012, el Ministerio de Salud entregó una guía técnica para trabajadores de altura que incluía una serie de acciones para mitigar los efectos de la hipoxia. Estudios anteriores han demostrado el efecto positivo del enriquecimiento de oxígeno en altitudes elevadas. El radiotelescopio Atacama Large Millimeter/submillimeter Arrays (ALMA) opera a 5.050 m (Array Operation Site, AOS) y es el único lugar en el mundo donde se han instalado tecnologías de adsorción por cambio de presión (PSA) y oxígeno líquido a gran escala. Aquí discutimos nuestra experiencia usando suplementos de oxígeno en ALMA, para prevenir el malestar y/o los riesgos asociados con la exposición a 5.050 m. Los operadores de antena experimentaron hipoxia hipobárica intermitente crónica (CIHH, trabajo por turnos 8 días HA*6 días descanso SL) durante 4 años. Se realizaron estudios para definir valores normales de saturación de O2 en OSF y AOS mediante registro continuo durante el turno. Los resultados no mostraron diferencias entre los procedimientos de producción (PSA u oxígeno líquido) en la regulación de la disponibilidad de oxígeno en las instalaciones de AOS. Como resultado, las instalaciones a gran escala tienen dificultades para alcanzar la concentración de oxígeno adecuada debido a fugas en áreas de alta movilidad. Además, la planta de PSA requiere de adecuación y mantenimiento para operar a gran altura.

Residential elevation and its effects on hypertension incidence among older adults living at low altitudes: a prospective cohort study

BACKGROUND@#Research on the relationship between residential altitude and hypertension incidence has been inconclusive. Evidence at low altitudes (i.e., <1,500 m) is scarce, let alone in older adults, a population segment with the highest hypertension prevalence. Thus, the objective of this study is to determine whether hypertension risk may be affected by altitude in older adults living at low altitudes.@*METHODS@#This prospective cohort study collected data from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). We selected 6,548 older adults (≥65 years) without hypertension at baseline (2008) and assessed events by the follow-up surveys done in 2011, 2014, and 2018 waves. The mean altitude of 613 residential units (county or district) in which the participants resided was extracted from the Digital Elevation Model (DEM) of the National Aeronautics and Space Administration (NASA) and was accurate to within 30 m. The Cox regression model with penalized splines examined the linear or nonlinear link between altitude and hypertension. A random-effects Cox regression model was used to explore the linear association between altitude and hypertension.@*RESULTS@#The overall rate of incident hypertension was 8.6 per 100-person years. The median altitude was 130.0 m (interquartile range [IQR] = 315.5 m). We observed that the exposure-response association between altitude and hypertension incidence was not linear. The shape of the exposure-response curve showed that three change points existed. Hypertension risk increased from the lowest to the first change point (247.1 m) and slightly fluctuated until the last change point (633.9 m). The risk decreased above the last change point. According to the categories stratified by the change points, altitude was only significantly associated with hypertension risk (hazard ratio [HR] = 1.003; 95% confidence interval [CI] = 1.002-1.005) under the first change point (247.1 m) after adjusting for related covariates.@*CONCLUSION@#Our study found that the association between altitude and hypertension risk might not be linear. We hope the further study can be conducted to confirm the generality of our findings.