Using the gli spirographic prediction equations to revisit the allometric relationships between lung volumes, height and age in adults.

The determination the forced vital capacity (FVC) and the forced expiratory volume in 1 second (FEV1) during spirometry studies, is at the core of the evaluation of the pulmonary function of patients with respiratory diseases. The Global Lung Function Initiative (GLI) offers the most extensive data set of normal lung functions available, which is currently used to determine the average expected/predicted FEV1 and FVC (predV), and their lower limit of normal (LLN, 5th percentile) at any given height and age for women and men. These prediction equations are currently expressed in a rather complex form: predV = exp [p+ (a x Ln (height) + (n x Ln (age)) + spline] and LLN = exp(Ln (predV) + Ln (1 - 1.645 x S x CV)/S); and are currently used to generate interpretations in commercialized spinographic system. However, as shown in this paper, these equations contain physiological and fundamental allometric information on lung volumes that become obvious when rewriting mean predicted values as a "simple" power function of height and LLN as a percentage of the mean predicted values. We therefore propose to present the equations of prediction obtained from the GLI data using simplified expressions in adults (18-95 years old) to reveal some of their physiological and allometric meaning. Indeed, when predicted FEV1 and FVC (predV) were expressed under the form predV= αx heightax b(age), the resulting exponent (a) ranges between 2 and 3, transforming the one dimension of a length (size) into a volume, akin to the third-order power (cubic) function of height historically used to predict lung volumes. Only one function, b (age), is necessary to replace all the factors related to age, including the tables of discrete data of spline functions original equations. Similarly, LLN can be expressed as LLN = c (age) xpredV to become a simple percentage of the predicted values, as a function of age. The equations with their respective new polynomial functions were validated in 52,764 consecutive spirometry tests performed in 2022 in 22,612 men and 30,152 women at the Cleveland Clinic. Using these equations, it become obvious that for both women and men, FEV1/FVC ratio decreases with the size as the exponent of the power function of height is lower for FEV1 than FVC. We conclude that rewriting the GLI predicted equations with simpler formulations restitutes to the GLI data some of their original allometric meaning, without altering the accuracy of their prediction.

Clinical implications of airway obstruction with normal or low FEV1 in childhood and adolescence.

BACKGROUND: Airway obstruction is defined by spirometry as a low forced expiratory volume in 1 s (FEV1) to forced vital capacity (FVC) ratio. This impaired ratio may originate from a low FEV1 (classic) or a normal FEV1 in combination with a large FVC (dysanaptic). The clinical implications of dysanaptic obstruction during childhood and adolescence in the general population remain unclear. AIMS: To investigate the association between airway obstruction with a low or normal FEV1 in childhood and adolescence, and asthma, wheezing and bronchial hyperresponsiveness (BHR). METHODS: In the BAMSE (Barn/Child, Allergy, Milieu, Stockholm, Epidemiology; Sweden) and PIAMA (Prevention and Incidence of Asthma and Mite Allergy; the Netherlands) birth cohorts, obstruction (FEV1:FVC ratio less than the lower limit of normal, LLN) at ages 8, 12 (PIAMA only) or 16 years was classified as classic (FEV1

Airway tree caliber heterogeneity and airflow obstruction among older adults.

Smaller mean airway tree caliber is associated with airflow obstruction and chronic obstructive pulmonary disease (COPD). We investigated whether airway tree caliber heterogeneity was associated with airflow obstruction and COPD. Two community-based cohorts (MESA Lung, CanCOLD) and a longitudinal case-control study of COPD (SPIROMICS) performed spirometry and computed tomography measurements of airway lumen diameters at standard anatomical locations (trachea-to-subsegments) and total lung volume. Percent-predicted airway lumen diameters were calculated using sex-specific reference equations accounting for age, height, and lung volume. The association of airway tree caliber heterogeneity, quantified as the standard deviation (SD) of percent-predicted airway lumen diameters, with baseline forced expired volume in 1-second (FEV1), FEV1/forced vital capacity (FEV1/FVC) and COPD, as well as longitudinal spirometry, were assessed using regression models adjusted for age, sex, height, race-ethnicity, and mean airway tree caliber. Among 2,505 MESA Lung participants (means ± SD age: 69 ± 9 yr; 53% female, mean airway tree caliber: 99 ± 10% predicted, airway tree caliber heterogeneity: 14 ± 5%; median follow-up: 6.1 yr), participants in the highest quartile of airway tree caliber heterogeneity exhibited lower FEV1 (adjusted mean difference: -125 mL, 95%CI: -171,-79), lower FEV1/FVC (adjusted mean difference: -0.01, 95%CI: -0.02,-0.01), and higher odds of COPD (adjusted odds ratio: 1.42, 95%CI: 1.01-2.02) when compared with the lowest quartile, whereas longitudinal changes in FEV1 and FEV1/FVC did not differ significantly. Observations in CanCOLD and SPIROMICS were consistent. Among older adults, airway tree caliber heterogeneity was associated with airflow obstruction and COPD at baseline but was not associated with longitudinal changes in spirometry.NEW & NOTEWORTHY In this study, by leveraging two community-based samples and a case-control study of heavy smokers, we show that among older adults, airway tree caliber heterogeneity quantified by CT is associated with airflow obstruction and COPD independent of age, sex, height, race-ethnicity, and dysanapsis. These observations suggest that airway tree caliber heterogeneity is a structural trait associated with low baseline lung function and normal decline trajectory that is relevant to COPD.

Smoking, respiratory symptoms, lung function and life expectancy: A longitudinal study of ageing.

BACKGROUND AND OBJECTIVE: Prognostic indices have been developed to predict various outcomes, including mortality. These indices and hazard ratios may be difficult for patients to understand. We investigated the association between smoking, respiratory symptoms and lung function with remaining life expectancy (LE) in older adults. METHODS: Data were from the 2004/05 English Longitudinal Study of Ageing (ELSA) (n = 8930), participants aged ≥50-years, with mortality data until 2012. Respiratory symptoms included were chronic phlegm and shortness of breath (SOB). The association between smoking, respiratory symptoms and FEV1/FVC, and remaining LE was estimated using a parametric survival function and adjusted for covariates including age at baseline and sex. RESULTS: The extent to which symptoms and FEV1/FVC predicted differences in remaining LE varied by smoking. Compared to asymptomatic never smokers with normal lung function (the reference group), in never smokers, only those with SOB had a significant reduction in remaining LE. In former and current smokers, those with respiratory symptoms had significantly lower remaining LE compared to the reference group if they had FEV1/FVC <0.70 compared to those with FEV1/FVC ≥0.70. Males aged 50-years, current smokers with SOB and FEV1/FVC <0.70, had a remaining LE of 19.2 (95%CI: 16.5-22.2) years, a decrease of 8.1 (5.3-10.8) years, compared to the reference group. CONCLUSION: Smoking, respiratory symptoms and FEV1/FVC are strongly associated with remaining LE in older people. The use of remaining LE to communicate mortality risk to patients needs further investigation.

Effect of twice daily inhaled albuterol on cardiopulmonary exercise outcomes, dynamic hyperinflation, and symptoms in secondhand tobacco-exposed persons with preserved spirometry and air trapping: a randomized controlled trial.

BACKGROUND: In tobacco-exposed persons with preserved spirometry (active smoking or secondhand smoke [SHS] exposure), air trapping can identify a subset with worse symptoms and exercise capacity. The physiologic nature of air trapping in the absence of spirometric airflow obstruction remains unclear. The aim of this study was to examine the underlying pathophysiology of air trapping in the context of preserved spirometry and to determine the utility of bronchodilators in SHS tobacco-exposed persons with preserved spirometry and air trapping. METHODS: We performed a double-blinded placebo-controlled crossover randomized clinical trial in nonsmoking individuals at risk for COPD due to exposure to occupational SHS who had preserved spirometry and air trapping defined as either a residual volume-to-total lung capacity ratio (RV/TLC) > 0.35 or presence of expiratory flow limitation (EFL, overlap of tidal breathing on maximum expiratory flow-volume loop) on spirometry at rest or during cardiopulmonary exercise testing (CPET). Those with asthma or obesity were excluded. Participants underwent CPET at baseline and after 4-week trials of twice daily inhalation of 180 mcg of albuterol or placebo separated by a 2-week washout period. The primary outcome was peak oxygen consumption (VO2) on CPET. Data was analyzed by both intention-to-treat and per-protocol based on adherence to treatment prescribed. RESULTS: Overall, 42 participants completed the entire study (66 ± 8 years old, 91% female; forced expiratory volume in 1 s [FEV1] = 103 ± 16% predicted; FEV1 to forced vital capacity [FVC] ratio = 0.75 ± 0.05; RV/TLC = 0.39 ± 0.07; 85.7% with EFL). Adherence was high with 87% and 93% of prescribed doses taken in the treatment and placebo arms of the study, respectively (P = 0.349 for comparison between the two arms). There was no significant improvement in the primary or secondary outcomes by intention-to-treat or per-protocol analysis. In per-protocol subgroup analysis of those with RV/TLC > 0.35 and ≥ 90% adherence (n = 27), albuterol caused an improvement in peak VO2 (parameter estimate [95% confidence interval] = 0.108 [0.014, 0.202]; P = 0.037), tidal volume, minute ventilation, dynamic hyperinflation, and oxygen-pulse (all P < 0.05), but no change in symptoms or physical activity. CONCLUSIONS: Albuterol may improve exercise capacity in the subgroup of SHS tobacco-exposed persons with preserved spirometry and substantial air trapping. These findings suggest that air trapping in pre-COPD may be related to small airway disease that is not considered significant by spirometric indices of airflow obstruction.

Evaluation of Forced Expiratory Volume in One Second and Forced Vital Capacity from Age and Height for Pulmonary Function Test.

BACKGROUND: Lung function tests (LFTs) are a collection of clinical examinations used to assess lung function and monitor potential declines in the lungs, respiratory muscles, and chest wall's mechanical performance. This cross-sectional study aimed to identify the relation of age and height to lung function. MATERIAL AND METHODS: The study was conducted at AlHussein Medical City, 70 adult male subjects were enrolled in the study. All subjects were screened physically to ensure that they were normal and there were no respiratory disorders that could affect the lung function. Age and height were taken for these subjects, forced vital capacity (FVC), FEV1 (Forced expiratory volume in first second) as well as FEV1 /FVC ratio were measured. RESULTS: The results of the study showed that the average values of FVC and FEV1 were 4.75 and 3.88 respectively. There was a significant negative correlation observed between age and FVC (r=0.48), FEV1 (r= 0.6). Also there was a significant positive correlation noticed between Height and FVC (r = 0.62), FEV1 (r =0.69). There was a very high correlation evidenced between FEV1 and FVC, the relation between FEV1 and FVC is practically height and age-independent. CONCLUSION: Our study highlights a great interest in the study of the relation between age, height, and lung function. The study also creates simple and convenience equations that can be used for reference standards in clinical practice to give reasonable theoretical values for a large sector of the population.

CONTEXTE: Les tests de fonction pulmonaire (TFP) regroupent une série d'examens cliniques utilisés pour évaluer la fonction pulmonaire et surveiller d'éventuelles réductions des performances mécaniques des poumons, des muscles respiratoires et de la paroi thoracique. Cette étude transversale visait à déterminer la relation entre l'âge et la taille et la fonction pulmonaire. MATÉRIEL ET MÉTHODES: L'étude a été menée à la ville médicale Al-Hussein. Soixante-dix sujets masculins adultes ont été inscrits à l'étude. Tous les sujets ont été soumis à un examen physique pour s'assurer qu'ils étaient en bonne santé et ne présentaient pas de troubles respiratoires susceptibles d'affecter la fonction pulmonaire. L'âge et la taille de ces sujets ont été relevés, et la capacité vitale forcée (CVF), le VEMS (volume expiratoire maximal en une seconde) ainsi que le rapport VEMS/CVF ont été mesurés. RÉSULTATS: Les résultats de l'étude ont montré que les valeurs moyennes de la CVF et du VEMS étaient respectivement de 4,75 et 3,88. Une corrélation négative significative a été observée entre l'âge et la CVF (r = 0,48) ainsi qu'entre l'âge et le VEMS (r = 0,6). De plus, une corrélation positive significative a été remarquée entre la taille et la CVF (r = 0,62) ainsi qu'entre la taille et le VEMS (r = 0,69). Une corrélation très élevée a été mise en évidence entre le VEMS et la CVF, la relation entre le VEMS et la CVF est pratiquement indépendante de la taille et de l'âge. CONCLUSION: Notre étude met en évidence un intérêt particulier pour l'étude de la relation entre l'âge, la taille et la fonction pulmonaire. L'étude crée également des équations simples et pratiques qui peuvent être utilisées comme référence dans la pratique clinique pour fournir des valeurs théoriques raisonnables pour une grande partie de la population. Mots-clés: VEMS, CVF, VEMS/CVF, Spirométrie.

Single breath counting technique to assess pulmonary function: a systematic review and meta-analysis.

Pulmonary function is usually assessed by measuring Vital Capacity (VC) using equipment such as a spirometer or ventilometer, but these are not always available to the population, as they are relatively expensive tests, difficult to transport and require trained professionals. However, the single breath counting technique (SBCT) appears as a possible alternative to respiratory function tests, to help in the pathophysiological understanding of lung diseases. The objective is to verify the applicability of the SBCT as a parameter for evaluating VC. This is a systematic review registered in the International Prospective Register of Systematic Reviews (CRD42023383706) and used for PubMed®, Scientific Electronic Library Online, LILACS, EMBASE, and Web of Science databases of articles published until January 2023. Methodological quality regarding the risk of bias was assessed using Quality Assessment of Diagnostic Accuracy Studies-2 and National Institutes of Health tools. Eleven of a total of 574 studies were included, of these, nine showed a correlation between VC and SBCT (weak in healthy, moderate in neuromuscular and strong in hospitalized patients). One study of hospitalized patients accurately identified a count value of 21 for a VC of 20 ml kg-1(Sensitivity = 94% and Specificity = 77%), and another estimated a count lower than 41 for a VC below 80% of predicted in patients with neuromuscular dystrophy (Sensitivity = 89% and Specificity = 62%), and another showed good intra and inter-examiner reproducibility in young, adult, and elderly populations. A meta-analysis of three studies showed a moderate correlation in subjects with neuromuscular diseases (r= 0.62, 95% CI = 0.52-0.71,p< 0.01). A high risk of bias was identified regarding the justification of the sample size and blinding of the evaluators. SBCT has been presented as an alternative to assess VC in the absence of specific equipment. There is a clear relationship between SBCT and VC, especially in neuromuscular and hospitalized individuals. New validation studies conducted with greater control of potential bias risks are necessary.

Artificial neural network identification of exercise expiratory flow-limitation in adults.

Identification of ventilatory constraint is a key objective of clinical exercise testing. Expiratory flow-limitation (EFL) is a well-known type of ventilatory constraint. However, EFL is difficult to measure, and commercial metabolic carts do not readily identify or quantify EFL. Deep machine learning might provide a new approach for identifying EFL. The objective of this study was to determine if a convolutional neural network (CNN) could accurately identify EFL during exercise in adults in whom baseline airway function varied from normal to mildly obstructed. 2931 spontaneous exercise flow-volume loops (eFVL) were placed within the baseline maximal expiratory flow-volume curves (MEFV) from 22 adults (15 M, 7 F; age, 32 yrs) in whom lung function varied from normal to mildly obstructed. Each eFVL was coded as EFL or non-EFL, where EFL was defined by eFVLs with expired airflow meeting or exceeding the MEFV curve. A CNN with seven hidden layers and a 2-neuron softmax output layer was used to analyze the eFVLs. Three separate analyses were conducted: (1) all subjects (n = 2931 eFVLs, [GRALL]), (2) subjects with normal spirometry (n = 1921 eFVLs [GRNORM]), (3) subjects with mild airway obstruction (n = 1010 eFVLs, [GRLOW]). The final output of the CNN was the probability of EFL or non-EFL in each eFVL, which is considered EFL if the probability exceeds 0.5 or 50%. Baseline forced expiratory volume in 1 s/forced vital capacity was 0.77 (94% predicted) in GRALL, 0.83 (100% predicted) in GRNORM, and 0.69 (83% predicted) in GRLOW. CNN model accuracy was 90.6, 90.5, and 88.0% in GRALL, GRNORM and GRLOW, respectively. Negative predictive value (NPV) was higher than positive predictive value (PPV) in GRNORM (93.5 vs. 78.2% for NPV vs. PPV). In GRLOW, PPV was slightly higher than NPV (89.5 vs. 84.5% for PPV vs. NPV). A CNN performed very well at identifying eFVLs with EFL during exercise. These findings suggest that deep machine learning could become a viable tool for identifying ventilatory constraint during clinical exercise testing.

Applicability of the Global Lung Function Initiative prediction equations in Hong Kong Chinese children.

BACKGROUND AND OBJECTIVE: This study aimed to assess the applicability of the Global Lung Function Initiative (GLI) prediction equations for spirometry in Hong Kong children and to develop prediction equations based on the Generalized Additive Models for Location, Scale, and Shape (GAMLSS) modeling. METHODS: Healthy Chinese children and adolescents aged 6-17 years old were recruited from randomly selected schools to undergo spirometry. The measurements were transformed to z-score according to the GLI-2012 equations for South East (SE) Asians and the GLI-2022 global race-neutral equations. Prediction equations for spirometric indices were developed with GAMLSS modeling to identify predictors. RESULTS: A total of 886 children (477 boys) with a mean age of 12.5 years (standard deviation [SD] 3.3 years) were included. By the GLI-2012 SE Asian equations, positive mean z-scores were observed in forced expiratory volume in 1 s (FEV1 ) (boys: 0.138 ± SD 0.828; girls: 0.206 ± 0.823) and forced vital capacity (FVC) (boys: 0.160 ± 0.930; girls: 0.310 ± 0.895) in both sexes. Negative mean z-scores were observed in FEV1 /FVC ratio (boys: -0.018 ± 0.998; girls: -0.223 ± 0.897). In contrast, negative mean z-scores in FEV1 and FVC, and positive mean z-scores in FEV1 /FVC were observed when adopting the GLI-2022 race-neutral equations. The mean z-scores were all within the range of ±0.5. By GAMLSS models, age and height were significant predictors for all four spirometric indices, while weight was an additional predictor for FVC and FEV1 . CONCLUSION: Our study provided data supporting the applicability of the GLI prediction equations in Hong Kong Chinese children. The GLI-2012 equations may underestimate FEV1 and FVC, while the GLI-2022 equations may overestimate the parameters, but the differences lie within the physiological limits. By GAMLSS modeling, weight was an additional predictor for FVC and FEV1 .

Characterizing the urinary proteome of prematurity-associated lung disease in school-aged children.

INTRODUCTION: Although different phenotypes of lung disease after preterm birth have recently been described, the underlying mechanisms associated with each phenotype are poorly understood. We, therefore, compared the urinary proteome for different spirometry phenotypes in preterm-born children with preterm- and term-born controls. METHODS: Preterm and term-born children aged 7-12 years, from the Respiratory Health Outcomes in Neonates (RHiNO) cohort, underwent spirometry and urine collection. Urine was analysed by Nano-LC Mass-Spectrometry with Tandem-Mass Tag labelling. The preterm-born children were classified into phenotypes of prematurity-associated preserved ratio impaired spirometry (pPRISm, FEV1 < lower limit of normal (LLN), FEV1/FVC ≥ LLN), prematurity-associated obstructive lung disease (POLD, FEV1 < LLN, FEV1/FVC < LLN) and preterm controls (FEV1 ≥ LLN,). Biological relationships between significantly altered protein abundances were analysed using Ingenuity Pathways Analysis software, and receiver operator characteristic curves were calculated. RESULTS: Urine was analysed from 160 preterm-born children and 44 term controls. 27 and 21 were classified into the pPRISm and POLD groups, respectively. A total of 785 proteins were detected. Compared to preterm-born controls, sixteen significantly altered proteins in the pPRISm group were linked to six biological processes related to upregulation of inflammation and T-cell biology. In contrast, four significantly altered proteins in the POLD group were linked with neutrophil accumulation. Four proteins (DNASE1, PGLYRP1, B2M, SERPINA3) in combination had an area under the curve of 0.73 for pPRISm and three combined proteins (S100A8, MMP9 and CTSC) had AUC of 0.76 for POLD. CONCLUSIONS: In this exploratory study, we demonstrate differential associations of the urinary proteome with pPRISm and POLD. TRIAL REGISTRATION: EudraCT: 2015-003712-20.

Systemic Markers of Lung Function and Forced Expiratory Volume in 1 Second Decline across Diverse Cohorts.

Rationale: Chronic obstructive pulmonary disease (COPD) is a complex disease characterized by airway obstruction and accelerated lung function decline. Our understanding of systemic protein biomarkers associated with COPD remains incomplete. Objectives: To determine what proteins and pathways are associated with impaired pulmonary function in a diverse population. Methods: We studied 6,722 participants across six cohort studies with both aptamer-based proteomic and spirometry data (4,566 predominantly White participants in a discovery analysis and 2,156 African American cohort participants in a validation). In linear regression models, we examined protein associations with baseline forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity (FVC). In linear mixed effects models, we investigated the associations of baseline protein levels with rate of FEV1 decline (ml/yr) in 2,777 participants with up to 7 years of follow-up spirometry. Results: We identified 254 proteins associated with FEV1 in our discovery analyses, with 80 proteins validated in the Jackson Heart Study. Novel validated protein associations include kallistatin serine protease inhibitor, growth differentiation factor 2, and tumor necrosis factor-like weak inducer of apoptosis (discovery ß = 0.0561, Q = 4.05 × 10-10; ß = 0.0421, Q = 1.12 × 10-3; and ß = 0.0358, Q = 1.67 × 10-3, respectively). In longitudinal analyses within cohorts with follow-up spirometry, we identified 15 proteins associated with FEV1 decline (Q < 0.05), including elafin leukocyte elastase inhibitor and mucin-associated TFF2 (trefoil factor 2; ß = -4.3 ml/yr, Q = 0.049; ß = -6.1 ml/yr, Q = 0.032, respectively). Pathways and processes highlighted by our study include aberrant extracellular matrix remodeling, enhanced innate immune response, dysregulation of angiogenesis, and coagulation. Conclusions: In this study, we identify and validate novel biomarkers and pathways associated with lung function traits in a racially diverse population. In addition, we identify novel protein markers associated with FEV1 decline. Several protein findings are supported by previously reported genetic signals, highlighting the plausibility of certain biologic pathways. These novel proteins might represent markers for risk stratification, as well as novel molecular targets for treatment of COPD.

A pilot study for development of a pulmonary function test induction jacket to automate effort in performing the forced vital capacity manoeuvre.

The pulmonary function test (PFT) induction jacket was invented to make the process of performing the forced vital capacity (FVC) manoeuvre with a computerized spirometer effortless and productive for both the patient and the medical practitioner. The jacket is composed of three layers of PVC material sealed together to form a single jacket with two chambers. The inner chamber is formed between the inner layer and the middle layer, in which cold water at a temperature of 10 °C is circulated using a connected water unit when triggered. Similarly, the outer chamber is formed between the middle layer and the outer layer, in which air is pressurized using a connected air unit. Thirty volunteers performed the FVC manoeuvre with and without wearing the jacket. There was no difference between the results in spirometry parameters in the participants without a jacket and those with a jacket. However, use of the jacket significantly reduced the number of trials the participants had to undergo to perform spirometry. The jacket automated the FVC manoeuvre by triggering a physiological inspiratory gasp using cold water and circumscribing pressurized air for expiration. Additionally, subsequent advancements in the jacket have been suggested.

Relación entre dimensiones antropométricas de tronco y valores de espirometría / Association between anthropometric dimensions of trunk and spirometry indices

Los objetivos del presente estudio fueron primero evaluar la asociación de dimensiones antropométricas de tórax y tronco con índices espirométricos, segundo, ajustar una ecuación de predicción con dimensiones antropométricas de tronco y tercero, comparar nuestro modelo predictivo con dos ecuaciones diagnósticas. Se evaluaron 59 estudiantes universitarios entre 20 y 40 años, de ambos sexos, sin hábito tabáquico. Las variables consideradas fueron: edad, sexo, peso, estatura, diámetro transverso de tórax, diámetro anteroposterior de tórax, perímetro de tórax, altura de tórax, altura de tronco, flujo espiratorio máximo (FEM), volumen espiratorio forzado en el primer segundo (VEF1) y capacidad vital forzada (CVF). Se utilizó el análisis de regresión múltiple para estimar los valores espirométricos en función de las variables demográficas y antropométricas. La CVF y el VEF1 tienen asociación lineal directa con el diámetro transverso de tórax, altura de tórax, perímetro de tórax y altura de tronco. Se ajustó una ecuación de regresión lineal múltiple que indicó que es posible estimar la CVF y el VEF11 en función de la altura de tronco y el perímetro de tórax para ambos sexos. Estas variables son capaces de explicar el 74 % de los valores de CVF y el 68 % de los valores de VEF1. Al comparar los valores obtenidos por nuestras ecuaciones predictivas con las ecuaciones de referencia nacional observamos que nuestros resultados son más cercanos a los de Quanjer et al. (2012) que a los de Knudson et al. (1983). La altura de tronco y el perímetro de tórax tienen asociación directa con el VEF1 y CVF y son buenos predictores del VEF1 y CVF en estudiantes universitarios. Nuestros valores estimados son más cercanos a las ecuaciones de Quanjer et al. (2012) en comparación a las estimaciones de Knudson (1983).

SUMMARY: The purposes of the present study were first to evaluate the association between anthropometric dimensions of the thorax and trunk with spirometric indices, second, to fit a prediction equation with anthropometric dimensions of the trunk, and third, to compare our predictive model with two diagnostic equations. Fifty-nine university students between 20 and 40 years old, of both sexes and non-smokers were recruited. Variables considered were age, sex, weight, height, chest transverse diameter, chest anteroposterior diameter, chest perimeter, chest height, trunk height, maximum expiratory flow (PEF), forced expiratory volume in the first second (FEV1) and forced vital capacity (FVC). Multiple regression analysis was used to estimate spirometric values based on demographic and anthropometric variables. FVC and FEV1 have a direct linear association with chest transverse diameter, chest height, chest circumference, and trunk height. A multiple linear regression equation was fitted, indicating that it is possible to estimate FVC and FEV1 as a function of trunk height and chest girth for both sexes. These variables can explain 74% of the FVC values and 68% of the FEV1 values. Comparing the values obtained by our predictive equations with the national reference equations, we observe that our results are closer to those of Quanjer et al. (2012) than to those of Knudson et al. (1983). Trunk height and chest circumference have a direct association with FEV1 and FVC and are good predictors of FEV1 and FVC in university students. Our estimated values are closer to Quanjer et al. (2012) than Knudson et al. (1983) prediction equations.

Saccadic oscillations as a biomarker of clinical symptoms in amyotrophic lateral sclerosis.

BACKGROUND: Among eye movements in amyotrophic lateral sclerosis (ALS), we identified the characteristics of square-wave jerks (SWJs) seen during times without visual fixation (VF) and analyzed their relationships with clinical parameters. MATERIALS AND METHODS: Clinical symptoms were evaluated and eye movements were tested using electronystagmography in 15 patients with ALS (10 men, 5 women; mean age, 66.9 ± 10.5 years). SWJs with and without VF were recorded, and their characteristics were identified. Relationships between each SWJ parameter and clinical symptoms were evaluated. Results were compared with eye movement data from 18 healthy individuals. RESULTS: The frequency of SWJs without VF was significantly higher in the ALS group than in the healthy group (P < 0.001). When the condition was changed from VF to no-VF in the ALS group, the frequency of SWJs was significantly higher in healthy subjects (P = 0.004). A positive correlation was seen between frequency of SWJs and percentage predicted forced vital capacity (%FVC) (R = 0.546, P = 0.035). CONCLUSION: The frequency of SWJs was higher with VF in healthy people, and was suppressed without VF. In contrast, the frequency of SWJs was not suppressed without VF in ALS patients. This suggests that SWJs without VF have some clinical significance in ALS patients. Moreover, a relationship was noted between the parameters of SWJs without VF in ALS patients and results of pulmonary function tests, suggesting that SWJs during times without VF may offer a clinical parameter of ALS.

Respiratory function of children and adolescents with osteogenesis imperfecta: respiratory muscle strength, forced vital capacity, and peak expiratory flow.

OBJECTIVE: This study aims to evaluate the respiratory function of children and adolescents with osteogenesis imperfecta (OI) followed up at a referral center. METHODS: A cross-sectional study was conducted with a non-probabilistic sample. Manovacuometry was performed with the measurement of maximal inspiratory pressure (MIP) and maximal expiratory pressure (MEP), and in addition, peak expiratory flow (PEF) and ventilometry were performed to measure forced vital capacity (FVC). RESULTS: In total, 23 individuals were evaluated, with a mean age of 11.6±3.4 years, 56.5% of whom were females. Regarding the classification of OI, 56.5% of the sample belonged to type IV, 30.5% to type III, and 13% to type I. The mean MIP was 64.4% of the predicted, and the mean MEP was 56.2% of the predicted. Overall, the mean PEF was 213.9 L/min, but only 140.6 L/min in the OI type III group. Median FVC was 1.9 L, corresponding to 110% of the predicted. CONCLUSIONS: Respiratory function of the study subjects was altered, with respiratory muscle strength values lower than expected in the whole sample, and peak expiratory flow was significantly reduced in the OI type III group.

Obesity Indices and Ventilatory Function Responses to High-Level Laser Therapy in Subjects with Abdominal Obesity.

Objective: The aim of this study is to investigate the effectiveness of pulsed Nd:YAG high-intensity laser therapy (HILT) on body weight (Wt), body-mass index (BMI), waist circumference (WC), forced vital capacity (FVC), and forced expiratory volume in 1 sec (FEV1) in young adults with abdominal obesity (AO). Materials and methods: Thirty-seven young adult males (age 19-25 years) with BMI >30 kg/m2 and WC >102 cm participated in this 12-week, randomized controlled study and were randomly allocated into either Group I [received pulsed Nd:YAG HILT plus moderate-intensity aerobic exercise training (AET) program] or Group II (received placebo pulsed Nd:YAG HILT plus the same AET program). The variables were evaluated pre- and poststudy. Results: Poststudy mean values and percentages of changes were calculated for Wt [83.7 ± 6.58 kg (-6.14%) and 88.71 ± 5.09 kg (-4.29%)], BMI [29.27 ± 1.06 kg/m2 (-6.14%) and 30.09 ± 1.23 kg/m2 (-4.24%)], WC [105.44 ± 5.84 cm (-3.78%) and 109.42 ± 4.9 cm (-1.74%)], FVC [4.79 ± 0.4 L (+13.6%) and 4.39 ± 0.66 L (+5.89%)], and FEV1 [4.04 ± 0.22 L (+16.4%) and 3.82 ± 0.39 L (+8.8%)] for Group I and Group II, respectively. Between groups, there were significant differences in mean values of Wt (p = 0.014), BMI (p = 0.04), WC (p = 0.03), FVC (p = 0.03), and FEV1 (p = 0.04) at the end of the study, but in favor of Group I. Conclusions: Utilizing the pulsed Nd:YAG HILT as an adjunctive therapeutic modality proved to be effective in improving the anthropometric indices and ventilatory functions in subjects with AO.

Characterising airway obstructive, dysanaptic and PRISm phenotypes of prematurity-associated lung disease.

INTRODUCTION: Although obstructive airway disease has been shown to be associated with prematurity, other spirometry phenotypes are less well described. OBJECTIVES: We characterised abnormal spirometry phenotypes in preterm-born children, including prematurity-associated obstructive lung disease (POLD, forced expiratory volume in 1 s (FEV1)

Differences in clinical significance of bronchodilator responses measured by forced expiratory volume in 1 second and forced vital capacity.

BACKGROUND: The clinical implication of bronchodilator response (BDR) is not fully understood. However, BDR is frequently present in patients with chronic obstructive pulmonary disease (COPD). We identified the differences in clinical features regarding BDR. In addition, we divided BDR into BDR for forced expiratory volume in 1 s (FEV1) and BDR for forced vital capacity (FVC; i.e., BDR-FEV1 and BDR-FVC, respectively) and analyzed clinical significance. METHODS: We used data from the Korea COPD Subgroup Study, a multicenter cohort study of COPD patients recruited from 54 centers in South Korea since April 2012. We analyzed differences in baseline characteristics, 1-year exacerbation rate, and 3-year FEV1 decline between BDR negative and positive patients. Moreover, we analyzed the differences in clinical features between BDR-FEV1 positive and negative patients and between BDR-FVC positive and negative patients. RESULTS: Of the 2,181 patients enrolled in this study, 366 (16.8%) were BDR positive. BDR positive patients were more likely to be ever-smokers and to have a lower body mass index and higher symptom scores compared to BDR negative patients. Baseline FEV1 and FEV1/FVC were lower in the BDR positive compared to the BDR negative group (1.7 ± 0.6 and 1.6 ± 0.5, respectively, p < 0.01; 50.9 ± 12.1 and 46.5 ± 14.8, respectively, p < 0.01). BDR positive patients were more likely to have been diagnosed with asthma-COPD overlap and to receive inhaled corticosteroids (ICS) than BDR negative patients. BDR-FVC patients were more likely to be smokers, suffer from worse symptoms and have lower lung function than those with no BDR-FVC. BDR had no significant effect on 1-year moderate to severe or severe exacerbation rates or 3-year annual FEV1 decline. Interactive effects of ICS and BDR on the exacerbation rate were not significant in any group. CONCLUSIONS: In this study, BDR positive patients were more likely to be ever-smokers and to have worse symptoms and lung function than BDR negative patients. BDR-FVC was associated with worse symptom control and lung function compared to BDR-FEV1. However, there were no significant differences in exacerbation rate or decline in lung function in any BDR group. In addition, the effects of ICS on exacerbations were not significant in any group.

Respiratory muscle strength and pulmonary function in unvaccinated athletes before and after COVID-19 infection: A prospective cohort study.

PURPOSE: We investigated abnormalities and recovery in respiratory function after COVID-19 infection in an unvaccinated elite athlete population. METHODS: Measurements included maximal inspiratory pressure (MIP), maximal expiratory pressure (MEP), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), and peak expiratory flow (PEF). RESULTS: The most frequent reported symptoms were fatigue with 80% and muscle/joint pain and headache with 50%, whereas only 10% reported dyspnoea and 30% cough. During follow-up, MIP was up to 13% and MEP up to 8% lower following COVID-19 infection. Likewise, FEV1 was up to 2% and FVC up to 5% lower. While MEP and FEV1 rapidly normalised, MIP and FVC still remained abnormal after 52 days of COVID-19 infection, thereby leading to a restrictive ventilatory pattern. PEF seemed unaffected during follow-up. CONCLUSIONS: COVID-19 decreases respiratory function in unvaccinated athletes despite reporting few respiratory symptoms and having mild disease. An initiative aimed at reducing the long-term adverse effects following COVID-19 infection seems warranted, which perhaps may be avoided through vaccination.

Early-life and health behaviour influences on lung function in early adulthood.

RATIONALE: Early-life exposures may influence lung function at different stages of the life course. However, the relative importance of characteristics at different stages of infancy and childhood are unclear. OBJECTIVES: To examine the associations and relative importance of early-life events on lung function at age 24 years. METHODS: We followed 7545 children from the Avon Longitudinal Study of Parents and Children from birth to 24 years. Using previous knowledge, we classified an extensive list of putative risk factors for low lung function, covering sociodemographic, environmental, lifestyle and physiological characteristics, according to timing of exposure: 1) demographic, maternal and child; 2) perinatal; 3) postnatal; 4) early childhood; and 5) adolescence characteristics. Lung function measurements (forced vital capacity (FVC), forced expiratory volume in 1 s (FEV1), FEV1/FVC and forced expiratory flow at 25-75% of FVC) were standardised for sex, age and height. The proportion of the remaining variance explained by each characteristic was calculated. The association and relative importance (RI) of each characteristic for each lung function measure was estimated using linear regression, adjusted for other characteristics in the same and previous categories. RESULTS: Lower maternal perinatal body mass index (BMI), lower birthweight, lower lean mass and higher fat mass in childhood had the largest RI (0.5-7.7%) for decreased FVC. Having no siblings, lower birthweight, lower lean mass and higher fat mass were associated with decreased FEV1 (RI 0.5-4.6%). Higher lean mass and childhood asthma were associated with decreased FEV1/FVC (RI 0.6-0.8%). CONCLUSIONS: Maternal perinatal BMI, birthweight, childhood lean and fat mass and early-onset asthma are the factors in infancy and childhood that have the greatest influence on early-adult lung function.