A Race-neutral Approach to the Interpretation of Lung Function Measurements.

Rationale: The use of self-reported race and ethnicity to interpret lung function measurements has historically assumed that the observed differences in lung function between racial and ethnic groups were because of thoracic cavity size differences relative to standing height. Very few studies have considered the influence of environmental and social determinants on pulmonary function. Consequently, the use of race and ethnicity-specific reference equations may further marginalize disadvantaged populations. Objectives: To develop a race-neutral reference equation for spirometry interpretation. Methods: National Health and Nutrition Examination Survey (NHANES) III data (n = 6,984) were reanalyzed with sitting height and the Cormic index to investigate whether body proportions were better predictors of lung function than race and ethnicity. Furthermore, the original GLI (Global Lung Function Initiative) data (n = 74,185) were reanalyzed with inverse-probability weights to create race-neutral GLI global (2022) equations. Measurements and Main Results: The inclusion of sitting height slightly improved the statistical precision of reference equations compared with using standing height alone but did not explain observed differences in spirometry between the NHANES III race and ethnic groups. GLI global (2022) equations, which do not require the selection of race and ethnicity, had a similar fit to the GLI 2012 "other" equations and wider limits of normal. Conclusions: The use of a single global spirometry equation reflects the wide range of lung function observed within and between populations. Given the inherent limitations of any reference equation, the use of GLI global equations to interpret spirometry requires careful consideration of an individual's symptoms and medical history when used to make clinical, employment, and insurance decisions.

Arterial Blood Gases in Normal Subjects at 2240 Meters Above Sea Level: Impact of Age, Gender, and Body Mass Index.

Background: The values of arterial blood gases (ABG) change with altitude above sea level; empirical verification is essential because ventilatory acclimatization varies with ethnicity and a population's adaptation. Objective: The aim of the study was to describe ABG in a healthy population residing at 2,240 meters above sea level, to identify the mean level of alveolar ventilation (PaCO2), and to know whether a progressive increase in PaCO2 occurs with age and the impact of increasing body mass index (BMI). Methods: We conducted a cross-sectional study in a referral center for respiratory diseases in Mexico City. Associations among variables with correlation coefficient and regression models of PaO2, SaO2, and P(A-a)O2 as dependent variables as a function of age, BMI, minute ventilation, or breathing frequency were explored. Results: Two hundred and seventeen healthy subjects were evaluated with a mean age of 40 ± 15 years, mean of the PaO2 was 71 ± 6 mmHg, SaO2 94% ± 1.6%, PaCO2 30.2 ± 3.4 mmHg, HCO3 20 ± 2 mmol/L, BE-2.9 ± 1.9 mmol/L, and the value of pH was 7.43 ± 0.02. In a linear regression, the main results were PaO2 = 77.5-0.16*age (p < 0.0001) and with aging P(A-a)O2 tended to increase 0.12 mmHg/year. PaCO2 in women increased with age by 0.075 mmHg/year (p = 0.0012, PaCO2 =26.3 + 0.075*age). SaO2 and PaO2 decreased significantly in women with higher BMI 0.14% and 0.52 mmHg per kg/m2, (p = 0.004 and 0.002 respectively). Conclusion: Mean PaCO2 was 30.7 mmHg, implying a mean alveolar ventilation of around 30% above that at sea level.

Maximal inspiratory and expiratory flow at moderate altitude: a study of a Latin American population.

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.

Body composition and risk factors associated with sarcopenia in post-COVID patients after moderate or severe COVID-19 infections.

BACKGROUND: Post-COVID-19 syndrome is characterized by diverse symptoms and abnormalities that persist beyond 12 weeks from the onset of acute COVID-19. Severity disease has been associated with more musculoskeletal alterations such as muscle weakness, dyspnea, and distance walking. The aim was to evaluate the impact of invasive mechanical ventilation (IMV) on body composition and investigate risk factors associated with sarcopenia in post-COVID-19 patients three months after moderate or severe COVID-19 infections. METHODS: Cross-sectional study. 530 patients with PCR-confirmed diagnoses of moderate to severe COVID-19, > 18 years old, oxygen saturation ≤ 93%, PaO2/FiO2 ratio < 300, who required hospitalization and were discharged were included. We excluded those who died before the follow-up visit, declined to participate, or could not be contacted. RESULTS: The mean age was 53.79 ± 12.90 years. IMV subjects had lower phase angle and handgrip strength and higher impedance index, frequency of low muscle mass, and low muscle strength than those without IMV. The risk factors of sarcopenia were > 60 years of age, diabetes, obesity, IMV, and prolonged hospital stay. The multivariate model showed that age > 60 years (OR: 4.91, 95% CI: 2.26-10.63), obesity (OR: 3.73, 95% CI: 1.21-11.54), and interaction between prolonged length of hospital stay and IMV (OR: 2.92; 95% CI: 1.21-7.02) were related to a higher risk of sarcopenia. CONCLUSION: Obesity and the interaction between prolonged length of hospital stay and IMV are associated with a higher risk of sarcopenia at 3 months after severe or moderate COVID-19 infection.

Salivary concentrations of cytokines and other analytes in healthy children.

BACKGROUND: Blood has been the usual biological fluid for measuring analytes, but there is mounting evidence that saliva may be also useful for detecting cytokines in a noninvasive way. Thus, in this study we aimed to determine concentration of cytokines and other analytes in saliva from a population of healthy children. METHODS: We collected un-stimulated whole saliva samples from clinically healthy children, and concentration of 17 cytokines and 12 other analytes were measured in supernatants. All values were adjusted by albumin content and were log-transformed before multivariate statistical analysis. RESULTS: We included 114 children (53.5% females) between 6.0 and 11.9 years old. The highest concentrations (medians, pg/µg albumin) were seen for visfatin (183.70) and adiponectin (162.26) and the lowest for IL-13 and IL-2 (~0.003). Albumin concentration was associated with age (rS = 0.39, p < 0.001). In the multivariate analysis, five analytes (C peptide, ghrelin, GLP-1, glucagon, leptin) inversely correlated with age and positively with height-for-age. Age was also positively associated with PAI-1, while height-for-age was also positively associated with insulin and visfatin. Finally, BMI-for-age had a positive correlation with GM-CSF and insulin. CONCLUSIONS: Herein, we provided concentration values for 29 analytes in saliva from healthy children that may be useful as preliminary reference framework in the clinical research setting.

Functional Respiratory Evaluation in the COVID-19 Era: The Role of Pulmonary Function Test Laboratories.

The pandemic character of coronavirus disease-19 (COVID-19) requires strategy changes designed to guarantee the safety of patients and health-care professionals. We are greatly concerned by the limitations in the operation of pulmonary function test (PFT) laboratories, since there is a high risk of disease progression in patients with chronic pulmonary diseases, and we are now faced by the influx of a new group of individuals in the recovery phase of post-COVID-19-syndrome that requires evaluation and follow-up of their respiratory function. To reestablish the operation of PFT laboratories limiting the risk of cross-contamination, we herein present the consensus reached by a group of experts in respiratory physiology, most of whom work in PFT laboratories in several Latin American countries, on the applicable recommendations for severe acute respiratory syndrome coronavirus 2 pneumonia survivors when undergoing PFT. We present the safety and hygiene measures that must be adopted in laboratories or centers where PFT is conducted in adults and/or children. These recommendations answer the following questions: which PFT is most recommended in subjects that have recovered from COVID-19; what quality control and safety measures should PFT laboratories implement during this pandemic? And how should we approach non-COVID-19 patients requiring PFT?

The MAL protein is crucial for proper membrane condensation at the ciliary base, which is required for primary cilium elongation.

The base of the primary cilium contains a zone of condensed membranes whose importance is not known. Here, we have studied the involvement of MAL, a tetraspanning protein that exclusively partitions into condensed membrane fractions, in the condensation of membranes at the ciliary base and investigated the importance of these membranes in primary cilium formation. We show that MAL accumulates at the ciliary base of epithelial MDCK cells. Knockdown of MAL expression resulted in a drastic reduction in the condensation of membranes at the ciliary base, the percentage of ciliated cells and the length of the cilia, but did not affect the docking of the centrosome to the plasma membrane or produce missorting of proteins to the pericentriolar zone or to the membrane of the remaining cilia. Rab8 (for which there are two isoforms, Rab8A and Rab8b), IFT88 and IFT20, which are important components of the machinery of ciliary growth, were recruited normally to the ciliary base of MAL-knockdown cells but were unable to elongate the primary cilium correctly. MAL, therefore, is crucial for the proper condensation of membranes at the ciliary base, which is required for efficient primary cilium extension.

Alternative polyadenylation in a family of paralogous EPB41 genes generates protein 4.1 diversity.

Alternative polyadenylation (APA) is a step in mRNA 3'-end processing that contributes to the complexity of the transcriptome by generating isoforms that differ in either their coding sequence or their 3'-untranslated regions (UTRs). The EPB41 genes, EPB41, EPB41L2, EPB41L3 and EPB41L1, encode an impressively complex array of structural adaptor proteins (designated 4.1R, 4.1G, 4.1B and 4.1N, respectively) by using alternative transcriptional promoters and tissue-specific alternative pre-mRNA splicing. The great variety of 4.1 proteins mainly results from 5'-end and internal processing of the EPB41 pre-mRNAs. Thus, 4.1 proteins can vary in their N-terminal extensions but all contain a highly homologous C-terminal domain (CTD). Here we study a new group of EPB41-related mRNAs that originate by APA and lack the exons encoding the CTD characteristic of prototypical 4.1 proteins, thereby encoding a new type of 4.1 protein. For the EPB41 gene, this type of processing was observed in all 11 human tissues analyzed. Comparative genomic analysis of EPB41 indicates that APA is conserved in various mammals. In addition, we show that APA also functions for the EPB41L2, EPB41L3 and EPB41L1 genes, but in a more restricted manner in the case of the latter 2 than it does for the EPB41 and EPB41L2 genes. Our study shows alternative polyadenylation to be an additional mechanism for the generation of 4.1 protein diversity in the already complex EPB41-related genes. Understanding the diversity of EPB41 RNA processing is essential for a full appreciation of the many 4.1 proteins expressed in normal and pathological tissues.

Small airway dysfunction in chronic hypersensitivity pneumonitis.

BACKGROUND AND OBJECTIVE: Lung biopsies from patients with hypersensitivity pneumonitis (HP) have demonstrated small airway (SA) involvement, but there is no information concerning SA function in HP, and it is unknown whether pharmacological treatment could modify its function. SA function in patients with chronic HP using ultrasonic pneumography (UPG) and impulse oscillometry (IOS) was explored. We also compared initial results with those obtained after 4 weeks of standardized treatment with azathioprine and prednisone. METHODS: The study group consisted of adults with recent diagnoses of HP. All patients completed UPG, IOS, spirometry, body plethysmography, single-breath carbon monoxide diffusing capacity (DLCO ) and the 6-min walk test (6MWT). The fraction of exhaled nitric oxide (FENO ) was obtained to assess eosinophilic airway inflammation. Measurements were taken at diagnosis and after 4 weeks of treatment. RESULTS: A total of 20 consecutive patients (16 women) with chronic HP participated in the study. Median age was 50 years (interquartile range (IQR): 42-54). At diagnosis, the UPG phase 3 slope was abnormally high, consistent with maldistribution of ventilation. For IOS, all patients had low reactance at 5 Hz (X5) and elevated reactance area (AX) reflecting low compliance, and only eight (40%) patients had elevated R5 (resistance at 5 Hz (total)) and R5-20 (resistance at 5 Hz-resistance at 20 Hz (peripheral)) attributed to SA resistance. In contrast, FENO parameters were within normal limits. After treatment, forced vital capacity (FVC), the 6-min walk distance and the distribution of ventilation showed significant improvement, although DLCO did not. CONCLUSION: Patients with chronic HP have SA abnormalities that are partially revealed by the UPG and IOS tests. Lung volumes, but not gas exchange, improved after treatment with azathioprine and prednisone.

Prevalence and Characteristics of Exercise-Induced Bronchoconstriction in High School and College Athletes at 2,240 m Altitude.

BACKGROUND: Athletes practicing strenuous physical activities may develop exercise-induced bronchoconstriction (EIB). We aimed to determine the prevalence and features of this condition in Mexico City (altitude, 2,240 m). METHODS: In the present study, 208 high school and college athletes performed a standardized EIB test on a treadmill. RESULTS: Responses to exercise had large between-subject variability in all physiological parameters (forced expiratory volume in one second [FEV1], heart rate, blood oxygen saturation level [SpO2], blood pressure), with nearly similar proportions of subjects in whom FEV1 increased or decreased. According to the recommended cut-off value of 10% FEV1 decrease, only 15 (7.2%) athletes had a positive EIB test. Weight lifters were more prone to develop EIB (three out of seven athletes; p = 0.01). Subjects with a positive EIB test already had a lower baseline forced expiratory volume in one second/forced vital capacity (FEV1/FVC) ratio (96.4 vs. 103.2% of predicted, respectively; p = 0.047), and developed more respiratory symptoms after exercise than subjects with a negative test. There were no differences with respect to age, gender, body mass index, history of asthma or atopic diseases, smoking habit, and exposure to potential indoor allergens. CONCLUSIONS: The relatively low prevalence of EIB in athletes from Mexico City raises the possibility that high altitude constitutes a protective factor for EIB. In contrast, weight lifters were especially prone to develop EIB, which suggests that repetitive Valsalva maneuvers could be a novel risk factor for EIB. There was a large between-subject variability of all physiological responses to exercise.

Prevalence and behavior of multidrug-resistant shiga toxin-producing Escherichia coli, enteropathogenic E. coli and enterotoxigenic E. coli on coriander.

The prevalence and behavior of multidrug-resistant diarrheagenic Escherichia coli pathotypes on coriander was determined. One hundred coriander samples were collected from markets. Generic E. coli were determined using the most probable number procedure. Diarrheagenic E. coli pathotypes (DEPs) were identified using two multiplex polymerase chain reaction procedures. Susceptibility to sixteen antibiotics was tested for the isolated DEPs strains by standard test. The behavior of multidrug-resistant DEPs isolated from coriander was determined on coriander leaves and chopped coriander at 25°± 2 °C and 3°± 2 °C. Generic E. coli and DEPs were identified, respectively, in 43 and 7% of samples. Nine DEPs strains were isolated from positive coriander samples. The identified DEPs included Shiga toxin-producing E. coli (STEC, 4%) enterotoxigenic E. coli (ETEC, 2%) and enteropathogenic E. coli (EPEC, 1%). All isolated DEPs strains exhibited multi-resistance to antibiotics. On inoculated coriander leaves stored at 25°± 2 °C or 3°± 2 °C, no growth was observed for multidrug-resistant DEPs strains. However, multidrug-resistant DEPs strains grew in chopped coriander: after 24 h at 25° ± 2 °C, DEPs strains had grown to approximately 3 log CFU/g. However, at 3°± 2 °C the bacterial growth was inhibited. To the best of our knowledge, this is the first report of the presence and behavior of multidrug-resistant STEC, ETEC and EPEC on coriander and chopped coriander.

Variability of FeNO in healthy subjects at 2240 meters above sea level.

Fraction of exhaled nitric oxide (FeNO) is a marker of eosinophilic airway inflammation. Altitude above sea level can affect measurements of this index, but there is only limited information regarding the diurnal variation (ante meridiem vs. post meridiem) and reproducibility of FeNO on consecutive days at moderate altitudes. To evaluate the diurnal variability of FeNO and assess its reproducibility over five consecutive days in healthy individuals living at 2240 m, and to compare the FeNO readings taken with two different analyzers. Healthy non-smoking adults were measured using NIOX MINO(®) or NOA 280i(®) devices. One group (n = 10) had readings taken morning and afternoon for five consecutive days with the NIOX MINO(®) equipment; while the second group (n = 17) was measured on only one morning but by both the electrochemical analyzer (NIOX MINO(®)) and the chemiluminescence method (NOA 280i(®)). The study group consisted of 27 subjects aged 28.7 ± 6 years. Morning and afternoon FeNO measurements were 15.2 ± 7.5 ppb and 15.2 ± 7.9 ppb (p = 0.9), respectively. The coefficient of variation (CV) of these measurements (a.m. vs. p.m.) was 10.7 %, and the coefficient of repeatability (CR), 4.2 ppb. The concordance correlation coefficient (CCC) between the two measures (morning vs. afternoon) was 0.91. The CV and CR of the five morning readings were 15.4 % and 4.3 ppb, respectively; while those of the five afternoon measures were 13.6 % and 3.5 ppb, respectively. The CCC between the NIOX MINO(®) equipment and the NOA-280i(®) device was 0.8, with 95 % limits of agreement of -8.35 to 0.29 ppb. In adults living at 2240 m above sea level, FeNO measurements show minimal diurnal variation, and readings are reproducible (<15 %) over a period of at least five consecutive days; however, the FeNO measurements obtained with the NIOX MINO(®) and NOA 280i(®) devices are not interchangeable due to the wide limits of agreement recorded.

Protein 4.1R binds to CLASP2 and regulates dynamics, organization and attachment of microtubules to the cell cortex.

The microtubule (MT) cytoskeleton is essential for many cellular processes, including cell polarity and migration. Cortical platforms, formed by a subset of MT plus-end-tracking proteins, such as CLASP2, and non-MT binding proteins such as LL5ß, attach distal ends of MTs to the cell cortex. However, the mechanisms involved in organizing these platforms have not yet been described in detail. Here we show that 4.1R, a FERM-domain-containing protein, interacts and colocalizes with cortical CLASP2 and is required for the correct number and dynamics of CLASP2 cortical platforms. Protein 4.1R also controls binding of CLASP2 to MTs at the cell edge by locally altering GSK3 activity. Furthermore, in 4.1R-knockdown cells MT plus-ends were maintained for longer in the vicinity of cell edges, but instead of being tethered to the cell cortex, MTs continued to grow, bending at cell margins and losing their radial distribution. Our results suggest a previously unidentified role for the scaffolding protein 4.1R in locally controlling CLASP2 behavior, CLASP2 cortical platform turnover and GSK3 activity, enabling correct MT organization and dynamics essential for cell polarity.

Functional respiratory assessment in interstitial lung disease.

Interstitial lung diseases are a heterogeneous group of disorders that affect, to a greater or lesser degree, the alveolus, peripheral airway, and septal interstitium. Functional assessment in patients suspected of having an interstitial lung disease has implications for diagnosis and makes it possible to objectively analyze both response to treatment and prognosis. Recently the clinical value of lung-diffusing capacity and the six-minute walking test has been confirmed, and these are now important additions to the traditional assessment of lung function that is based on spirometry. Here we review the state-of-the-art methods for the assessment of patients with interstitial lung disease.

Altitude Above Sea Level and Body Mass Index as Determinants of Oxygen Saturation in Children: The SON@ Study.

BACKGROUND: Altitude above sea level and body mass index are well-recognized determinants of oxygen saturation in adult populations; however, the contribution of these factors to oxygen saturation in children is less clear. OBJECTIVE: To explore the contribution of altitude above sea level and body mass index to oxygen saturation in children. METHODS: A multi-center, cross-sectional study conducted in nine cities in Mexico. Parents signed informed consent forms and completed a health status questionnaire. Height, weight, and pulse oximetry were recorded. RESULTS: We studied 2,200 subjects (52% girls) aged 8.7 ± 3.0 years. Mean body mass index, z-body mass index, and oxygen saturation were 18.1 ± 3.6 kg·m-2, 0.58 ± 1.3, and 95.5 ± 2.4%, respectively. By multiple regression analysis, altitude proved to be the main predictor of oxygen saturation, with non-significant contributions of age, gender, and body mass index. According to quantile regression, the median estimate of oxygen saturation was 98.7 minus 1.7% per km of altitude above sea level, and the oxygen saturation fifth percentile 97.4 minus 2.7% per km of altitude. CONCLUSIONS: Altitude was the main determinant of oxygen saturation, which on average decreased 1.7% per km of elevation from a percentage of 98.7 at sea level. In contrast with adults, this study in children found no association between oxygen saturation and obesity or age.

Small airway disease in post-acute COVID-19 syndrome, a non-conventional approach in three years follow-up of a patient with long COVID: a case report.

BACKGROUND: Small airways disease (SAD), a novel finding described in post-acute COVID-19 patients, should be suspected when respiratory symptoms continue, air trapping persists on expiratory CT scans, and imaging findings fail to improve despite objectively better conventional pulmonary function test (PFT) parameters. The forced oscillation technique (FOT) and Multiple breathing washout (MBW) are both very sensitive methods for detecting anomalies in the peripheral airways. CASE PRESENTATION: We discuss the case of a 60-year-old Hispanic patient who had severe COVID-19 pneumonia and developed dyspnea, fatigue, and limited daily activity a year later. The PFTs revealed restrictive lung disease, as seen by significant diffusing capacity of the lungs for carbon monoxide (DLCO) decrease, severe desaturation, and poor 6-min walk test (6MWT) performance. The patient was treated with lowering corticosteroids as well as pulmonary rehabilitation (PR). During the 24-month follow-up, the dyspnea and fatigue persisted. On PFTs, 6MWT performance and restricted pattern improved slightly, but MBW discovered significant ventilatory inhomogeneity. FOT revealed substantial peripheral airway obstructive abnormalities. On CT scans, air trapping and ground-glass opacities (GGO) improved somewhat. The patient used a bronchodilator twice a day and low-dose inhaled corticosteroids (160 µg of budesonide and 4.5 µg of formoterol fumarate dihydrate) for nine months. PR sessions were resuming. The restricting parameters were stabilized and the DLCO had normalized after 36 months, with a 6MWT performance of 87% but significant desaturation. The CT scan revealed traction bronchiectasis, low GGO, and persistent air trapping. Without normalization, FOT and MBW scores improved, indicating small airway disease. CONCLUSIONS: The necessity of integrating these tests when detecting SAD is emphasized in our paper. This article lays the foundation for future research into the best ways to manage and monitor SAD in post-acute COVID-19 patients.

Lung function is related to salivary cytokines and hormones in healthy children. An exploratory cross-sectional study.

Pulmonary mechanics has been traditionally viewed as determined by lung size and physical factors such as frictional forces and tissue viscoelastic properties, but few information exists regarding potential influences of cytokines and hormones on lung function. Concentrations of 28 cytokines and hormones were measured in saliva from clinically healthy scholar children, purposely selected to include a wide range of body mass index (BMI). Lung function was assessed by impulse oscillometry, spirometry, and diffusing capacity for carbon monoxide, and expressed as z-score or percent predicted. Ninety-six scholar children (55.2% female) were enrolled. Bivariate analysis showed that almost all lung function variables correlated with one or more cytokine or hormone, mainly in boys, but only some of them remained statistically significant in the multiple regression analyses. Thus, after adjusting by height, age, and BMI, salivary concentrations of granulocyte-macrophage colony-stimulating factor (GM-CSF) in boys were associated with zR5-R20 and reactance parameters (zX20, zFres, and zAX), while glucagon inversely correlated with resistances (zR5 and zR20). Thus, in physiological conditions, part of the mechanics of breathing might be influenced by some cytokines and hormones, including glucagon and GM-CSF. This endogenous influence is a novel concept that warrants in-depth characterization.

Dynapenia and Sarcopenia in Post-COVID-19 Syndrome Hospitalized Patients Are Associated with Severe Reduction in Pulmonary Function.

BACKGROUND: After hospital discharge, post-COVID-19 syndrome has been observed to be associated with impaired diffusing capacity, respiratory muscle strength, and lung imaging abnormalities, in addition to loss of muscle mass/strength, sarcopenia, and obesity impact exercise tolerance, pulmonary functions, and overall prognosis. However, the relationship between lung function and the coexistence of obesity with low muscle strength and sarcopenia in post-COVID-19 patients remains poorly investigated. Therefore, our aim was to evaluate the association between lung function and the coexistence of obesity with dynapenia and sarcopenia in post-COVID-19 syndrome patients. METHODS: This cross-sectional study included subjects who were hospitalized due to moderate to severe COVID-19, as confirmed by PCR testing. Subjects who could not be contacted, declined to participate, or died before the follow-up visit were excluded. RESULTS: A total of 711 subjects were evaluated; the mean age was 53.64 ± 13.57 years, 12.4% had normal weight, 12.6% were dynapenic without obesity, 8.3% had sarcopenia, 41.6% had obesity, 21.2% had dynapenic obesity, and 3.8% had sarcopenic obesity. In terms of pulmonary function, the dynapenic subjects showed decreases of -3.45% in FEV1, -12.61 cmH2O in MIP, and -12.85 cmH2O in MEP. On the other hand, the sarcopenic subjects showed decreases of -6.14 cmH2O in MIP and -11.64 cmH2O in MEP. The dynapenic obesity group displayed a reduction of -12.13% in PEF. CONCLUSIONS: In post-COVID-19 syndrome, dynapenia and sarcopenia-both with and without obesity-have been associated with lower lung function.

Effect of Altitude on Respiratory Functional Status in COVID-19 Survivors: Results from a Latin American Cohort-FIRCOV.

Laura Gochicoa-Rangel, Santiago C. Arce, Carlos Aguirre-Franco, Wilmer Madrid-Mejía, Mónica Gutiérrez-Clavería, Lorena Noriega-Aguirre, Patricia Schonffeldt-Guerrero, Agustín Acuña-Izcaray, Arturo Cortés-Telles, Luisa Martínez-Valdeavellano, Federico Isaac Hernández-Rocha, Omar Ceballos-Zúñiga, Rodrigo Del Rio Hidalgo, Sonia Sánchez, Erika Meneses-Tamayo, and Iván Chérrez-Ojeda; and on Behalf of the Respiratory Physiology Project in COVID-19 (FIRCOV). Effect of altitude on respiratory functional status in COVID-19 survivors: results from a Latin American Cohort-FIRCOV. High Alt Med Biol 24:37-48, 2023. Persistent symptoms and lung function abnormalities are common in COVID-19 survivors. Objectives: To determine the effect of altitude and other independent variables on respiratory function in COVID-19 survivors. Methods: Analytical, observational, cross-sectional cohort study done at 13 medical centers in Latin America located at different altitudes above sea level. COVID-19 survivors were invited to perform pulmonary function tests at least 3 weeks after diagnosis. Results: 1,368 participants (59% male) had mild (20%), moderate (59%), and severe (21%) disease. Restriction by spirometry was noted in 32%; diffusing capacity of the lung for carbon monoxide (DLCO) was low in 43.7%; and 22.2% walked less meters during the 6-minute walk test (6-MWT). In multiple linear regression models, higher altitude was associated with better spirometry, DLCO and 6-MWT, but lower oxygen saturation at rest and during exercise. Men were 3 times more likely to have restriction and 5.7 times more likely to have a low DLCO. Those who had required mechanical ventilation had lower DLCO and walked less during the 6-MWT. Conclusions: Men were more likely to have lower lung function than women, even after correcting for disease severity and other factors. Patients living at a higher altitude were more likely to have better spirometric patterns and walked farther but had lower DLCO and oxygen saturation.