Proteomic associations with forced expiratory volume: a Mendelian randomisation study

BACKGROUND

A decline in forced expiratory volume (FEV1) is a hallmark of respiratory diseases that are an important cause of morbidity among the elderly. While some data exist on biomarkers that are related to FEV1, we sought to do a systematic analysis of causal relations of biomarkers with FEV1.

METHODS

Data from the population-based AGES-Reykjavik study were used. Serum proteomic measurements were done using 4782 DNA aptamers (SOMAmers). Data from 1479 participants with spirometric data were used to assess the association of SOMAmer measurements with FEV1 using linear regression. Bi-directional two-sample Mendelian randomisation (MR) analyses were done to assess causal relations of observationally associated SOMAmers with FEV1, using genotype and SOMAmer data from 5368 AGES-Reykjavik participants and genetic associations with FEV1 from a publicly available GWAS (n = 400,102).

RESULTS

In observational analyses, 530 SOMAmers were associated with FEV1 after multiple testing adjustment (FDR < 0.05). The most significant were Retinoic Acid Receptor Responder 2 (RARRES2), R-Spondin 4 (RSPO4) and Alkaline Phosphatase, Placental Like 2 (ALPPL2). Of the 257 SOMAmers with genetic instruments available, eight were associated with FEV1 in MR analyses. Three were directionally consistent with the observational estimate, Thrombospondin 2 (THBS2), Endoplasmic Reticulum Oxidoreductase 1 Beta (ERO1B) and Apolipoprotein M (APOM). THBS2 was further supported by a colocalization analysis. Analyses in the reverse direction, testing whether changes in SOMAmer levels were caused by changes in FEV1, were performed but no significant associations were found after multiple testing adjustments.

CONCLUSIONS

In summary, this large scale proteogenomic analyses of FEV1 reveals circulating protein markers of FEV1, as well as several proteins with potential causality to lung function.

Associations of personal urinary volatile organic compounds and lung function in children

BACKGROUND

We investigated the correlation between urine VOC metabolites and airway function in children exposed to anthropogenic volatile organic compounds (VOCs), notable pollutants impacting respiratory health.

METHODS

Out of 157 respondents, 141 completed skin prick tests, spirometry, IOS, and provided urine samples following the International Study of Asthma and Allergies in Childhood (ISAAC)-related questions. Allergic sensitization was assessed through skin prick tests, and airway functions were evaluated using spirometry and impulse oscillometry (IOS). Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) was recorded and FEV1/FVC ratio was calculated. Airway mechanics parameters including respiratory resistance at 5 Hz (Rrs5) mean respiratory resistance between 5 Hz and 20 Hz (Rrs5-20), were also recorded. Urine concentrations of metabolites of benzene, ethylbenzene, toluene, xylene, styrene, formaldehyde, carbon-disulfide were analyzed by gas chromatography/tandem mass spectroscopy.

RESULTS

The median age at study participation was 7.1 (SD 0.3) years. Muconic acid (benzene metabolites) and o-methyl-hippuric acid (xylene metabolites) above medians were associated with a significant increase in Rrs5 (muconic acid: aβ = 0.150, p = .002; o-methyl-hippuric acid: aβ = 0.143, p = .023) and a decrease in FEV1/FVC (o-methyl-hippuric acid: aβ = 0.054, p = .028) compared to those below median. No associations were observed for Rrs5-20 and FEV1 between the groups categorized as above and below the median (all parameter p values > .05).

CONCLUSIONS

Elevated levels of benzene and xylene metabolites were associated with a significant increase in Rrs5 and a decrease in FEV1/FVC, related to increased resistance and restrictive lung conditions compared to individuals with concentrations below the median.

Association between nebuliser therapies adherence and visit-to-visit variability of FEV1 in patients with cystic fibrosis

At the same level of lung function, some patients with cystic fibrosis have large variations in their FEV1 percent predicted (FEV1pp) values while others have stable values. We hypothesised that lower adherence to nebuliser therapies was associated with higher FEV1pp variability. We conducted a post hoc analysis of the ACtiF trial data. Adherence was calculated using data from data-logging nebulisers, and FEV1pp variability using the coefficient of variation equation. Amongst the 543 patients included in the analysis, those poorly adherent (adherence < 50%) had a higher FEV1pp variability than patients moderately (50 to < 80%) and highly adherent (≥ 80%), with median values (IQR1-3) of 8.1% (4.9-13.7), 6.3% (3.9-9.8), and 6.3% (3.9-9.3) respectively (p < 0.01). This result was confirmed by a multiple linear regression including adherence as a continuous variable (p < 0.01). Further studies are needed to determine the implications of these differences in FEV1pp variability on the prognosis of patients.

Comparison of different reference values for lung function: implications of inconsistent use among centers

BACKGROUND

For interpretation of pulmonary function tests (PFTs), reference values based on sex, age, height and ethnicity are needed. In Norway, the European Coal and Steel Community (ECSC) reference values remain widely used, in spite of recommendations to implement the more recent Global Lung Function Initiative (GLI) reference values.

OBJECTIVE

To assess the effects of changing from ECSC to GLI reference values for spirometry, DLCO and static lung volumes, using a clinical cohort of adults with a broad range in age and lung function.

METHODS

PFTs from 577 adults (18-85 years, 45% females) included in recent clinical studies were used to compare ECSC and GLI reference values for FVC, FEV1, DLCO, TLC and RV. Percent predicted and lower limit of normal (LLN) were calculated. Bland-Altman plots were used to assess agreement between GLI and ECSC % predicted values.

RESULTS

In both sexes, GLI % predicted values were lower for FVC and FEV1, and higher for DLCO and RV, compared to ECSC. The disagreement was most pronounced in females, with mean (SD) difference 15 (5) percent points (pp) for DLCO and 17 (9) pp for RV (p < 0.001). With GLI, DLCO was below LLN in 23% of the females, with ECSC in 49% of the females.

CONCLUSIONS

The observed differences between GLI and ECSC reference values are likely to entail significant consequences with respect to criteria for diagnostics and treatment, health care benefits and inclusion in clinical trials. To ensure equity of care, the same reference values should be consistently implemented across centers nationwide.

Effect of barometric pressure on single-breath carbon monoxide diffusing capacity

BACKGROUND

Single-breath diffusing capacity for carbon monoxide (D_LCO) quantifies gas transfer in the lungs. D_LCO measurement is affected by barometric pressure (Pb) and alveolar partial pressure of oxygen (PAO₂). The current equations for adjusting D_LCO for Pb and PAO₂ may not be accurate given advances in test performance and technology. We quantify changes in D_LCO with alterations in Pb in normal and COPD subjects, determine the accuracy of the current Pb and PAO₂ adjustment equations and develop updated adjustment equations.

METHODS

We measured D_LCO in 13 normal and 10 COPD subjects at 1330 m altitude and in a hypobaric/hyperbaric chamber at altitudes of sea-level and 2500 m; six normal subjects were tested at 3600 m. We determined if there were significant differences in D_LCO between altitudes. We developed an equation for adjusting D_LCO for changes in Pb from sea-level. We compared this equation with the existing Pb adjustment equation in normal and COPD subjects. We determined the accuracy of the current PAO₂ adjustment equation and developed a new PAO₂ adjustment equation.

RESULTS

D_LCO significantly increased with decreasing Pb. We developed a Pb adjustment equation that adjusts D_LCO measured at altitudes between 1330 m and 3600 m to sea-level values. This Pb adjustment equation yields D_LCO results that are not significantly different than the currently recommended equation. We developed a more accurate PAO₂ adjustment equation.

CONCLUSION

D_LCO measurement is significantly affected by altitude. We developed equations that accurately adjust D_LCO for changes in Pb and PAO₂ in normal and COPD subjects.

Chronic respiratory symptoms and lung function parameters in large-scale wood factory workers in Addis Ababa, Ethiopia: a comparative cross-sectional study

BACKGROUND

Occupational wood dust causes chronic respiratory health problems as well as a decline in lung function. However, data on the prevalence of chronic respiratory symptoms and lung function parameters among large-scale wood factories workers in Ethiopia producing furniture are limited. The objective of this study was to determine the prevalence of chronic respiratory symptoms, lung function measures, and associated factors among large-scale wood industry workers in Addis Ababa, Ethiopia.

METHODS

An institution-based cross-sectional study was conducted among 232 wood workers and 232 controls. Participants for the study were selected using stratified and systematic sampling from soft drink and wood factories. The chronic respiratory symptoms were assessed using a modified American Thoracic Society (ATS) questionnaire, and lung function tests were performed using an Easy on PC spirometer in accordance with the ATS standards for spirometry. The data were imported into Epi-data version 4.4.2 and analyzed with SPSS version 23. Poisson regression, Multivariate linear regression and multivariable logistic regression analysis were used.

RESULTS

The prevalence ratio of overall chronic respiratory symptoms was significantly higher among woodworkers (65.7%) compared to controls (23.3%) in this study (PR = 2.17, 95% CI: 1.51-3.12). Current chronic respiratory symptoms were associated with gender, and previous chronic respiratory disease. Woodworkers had significantly lower Forced vital capacity (FVC) and Forced expiratory volume in the first second (FEV1) when compared to controls.

CONCLUSION

Woodworkers had a higher prevalence of chronic respiratory symptoms and lower lung function measures, which lowered lung capacity when compared to controls. To reduce workers' exposure to wood dust, engineering control methods should be implemented.

Respiratory morbidity in children with congenital heart disease

OBJECTIVE

To evaluate the respiratory outcome in children with congenital heart disease (CHD), considering recent management procedures and the CHD pathophysiology.

DESIGN AND SETTING

Clinical and functional respiratory outcome were evaluated in 8-year-old children with isolated CHD followed up from birth in the prospective population-based EPICARD cohort.

PATIENTS

Children were assigned to two groups, based on the pathophysiology of the CHD: CHDs with left-to-right shunt (n = 212) and CHDs with right outflow tract obstruction (n = 113).

RESULTS

Current wheezing episodes were observed in 15% of the children with isolated CHD and left-to-right shunt, and 11% of the children with isolated CHD and right outflow tract obstruction (not significant). Total lung capacity (TLC) was the only respiratory function parameter that significantly differed between the two groups. It was lower in children with left-to-right shunt (88.72 ± 0.65% predicted) than in those with right outflow tract obstruction (91.84 ± 0.96, p = 0.006). In multivariate analysis, CHD with left-to-right shunt (coeff. [95% CI]: -3.17 [-5.45; -0.89]) and surgery before the age of 2 months (-6.52 [-10.90; -2.15]) were identified as independent factors associated with significantly lower TLC values.

CONCLUSION

Lower TLC remains a long-term complication in CHD, particularly in cases with left-to-right shunt and in patients requiring early repair. These findings suggest that an increase in pulmonary blood flow may directly impair lung development.

Cord blood soluble Fas ligand linked to allergic rhinitis and lung function in seven-year-old children

BACKGROUND

Serum or cord blood soluble Fas ligand (FasL) has been related to asthma, allergic rhinitis, and atopic dermatitis in cross-sectional and short-term follow-up studies. However, the association of cord blood soluble FasL with long-term allergic outcomes has seldom been investigated.

METHODS

The Prediction of Allergies in Taiwanese Children birth cohort study recruited healthy newborns upon delivery. At birth, blood was collected from the umbilical cords of these children, and the cord blood soluble Fas ligand levels were measured. At the age of seven years, the allergic outcome of each child was diagnosed by pediatric allergists and pulmonologists. Tests were conducted to measure the specific immunoglobulin E, fractional exhaled nitric oxide (FeNO), and pulmonary function levels of each child.

RESULTS

Cord blood soluble FasL levels were higher in seven-year-old children with allergic rhinitis (Odds ratio [OR] = 2.41, p = 0.012) and expiratory airway obstruction (the highest forced expiratory volume in 1 second/forced vital capacity < 90%, OR = 2.11, p = 0.022). The FeNO and Dermatophagoides pteronyssinus-specific immunoglobulin E levels of seven-year-old children were positively correlated with cord blood soluble FasL levels (p = 0.006 and 0.02, respectively).

CONCLUSION

In this birth cohort, the cord blood soluble FasL levels were associated with allergic rhinitis, obstructive-type lung function, FeNO, and house dust mite sensitization in 7-year-old children. The cord blood soluble FasL level might be used as a predictor for allergic diseases in children who are 7 years old.

Air Trapping Is Associated with Heterozygosity for Alpha-1 Antitrypsin Mutations in Patients with Asthma

BACKGROUND

Alpha-1 antitrypsin deficiency (AATD) is a hereditary disorder involving lungs, characterized by low serum concentration of the protein alpha-1 antitrypsin (AAT) also called proteinase inhibitor (PI). Asthma is common in AATD patients, but there are only few data on respiratory function in asthmatic patients with AATD.

OBJECTIVES

The aim of the study was to evaluate lung function in asthmatic outpatients with mutation in the SERPINA1 gene coding for AAT versus asthmatic subjects without mutation.

METHODS

We performed the quantitative analysis of the serum concentration of AAT in 600 outpatients affected by mild to moderate asthma from the University Hospital of Parma, Italy. Fifty-seven of them underwent the genetic analysis subsequently; they were subdivided into mutated and non-mutated subjects. All the mutated patients had a heterozygous genotype, except 1 (PI*SS). We assessed the lung function through a flow-sensing spirometer and the small airway parameters through an impulse oscillometry system.

RESULTS

The values of forced vital capacity (% predicted) and those of the residual volume to total lung capacity ratio (%) were, respectively, lower and higher in patients mutated versus patients without mutation, showing a significantly greater air trapping (p = 0.014 and p = 0.017, respectively). Moreover, patients with mutation in comparison to patients without mutation showed lower forced expiratory volume in 3 s (% predicted) and forced expiratory volume in 6 s (L) spirometric values, reflecting a smaller airways contribution.

CONCLUSIONS

In asthmatic patients, heterozygosity for AAT with PI*MZ and PI*MS genotypes was associated with small airway dysfunction and with lung air trapping.

[Approaches to the pre-operative functional assessment of patients with lung cancer and preoperative rehabilitation]

Surgery is the best treatment for early lung cancer but requires a preoperative functional evaluation to identify patients who may be at a high risk of complications or death. Guideline algorithms include a cardiological evaluation, a cardiopulmonary assessment to calculate the predicted residual lung function, and identify patients needing exercise testing to complete the evaluation. According to most expert opinion, exercise tests have a very high predictive value of complications. However, since the publication of these guidelines, minimally-invasive surgery, sublobar resections, prehabilitation and enhanced recovery after surgery (ERAS) programmes have been developed. Implementation of these techniques and programs is associated with a decrease in postoperative mortality and complications. In addition, the current guidelines and the cut-off values they identified are based on early series of patients, and are designed to select patients before major lung resection (lobectomy-pneumonectomy) performed by thoracotomy. Therefore, after a review of the current guidelines and a brief update on prehabilitation (smoking cessation, exercise training and nutritional aspects), we will discuss the need to redefine functional criteria to select patients who will benefit from lung surgery.

Medical devices in allergy practice

Medical devices provide people with some health benefits in terms of diagnosis, prevention, treatment, and monitoring of disease processes. Different medical specialties use varieties of medical devices more or less specific for them. Allergology is an interdisciplinary field of medical science and teaches that allergic reactions are of systemic nature but can express themselves at the level of different organs across the life cycle of an individual. Subsequently, medical devices used in allergology could be regarded as: 1) general, servicing the integral diagnostic and management principles and features of allergology, and 2) organ specific, which are shared by organ specific disciplines like pulmonology, otorhinolaryngology, dermatology, and others. The present position paper of the World Allergy Organization (WAO) is meant to be the first integral document providing structured information on medical devices in allergology used in daily routine but also needed for sophisticated diagnostic purposes and modern disease management. It is supposed to contribute to the transformation of the health care system into integrated care pathways for interrelated comorbidities.

Functional Examination of the Upper and Lower Airways in Asthma and Respiratory Allergic Diseases: Considerations in the Post-SARS-CoV-2 Era

Airway examination procedures can potentially transmit infectious diseases to patients and to the health care professionals who perform them via various mechanisms. The COVID-19 pandemic has halted most of the activity of the clinics and laboratories involved in assessment of lung and nasal function, and clear recommendations in this regard have been made. Today, we still do not know for sure what its consequences will be in the short or long term, since important gaps remain in our knowledge of aspects as fundamental as virus transmission mechanisms, pathophysiology, immune response, and diagnosis. In this review, we study the examination techniques used to assess patients with respiratory allergy, asthma, and associated diseases during this period and highlight their possible advantages and disadvantages. Therefore, we focus on exploring the entire upper and lower airways, from the perspective of the safety of both health professionals and patients and their specific characteristics. We also analyze the intrinsic value of these interventions in terms of diagnosis and patient management. The changing situation of COVID-19 may mean that some of the assertions presented in this review will have to be modified in the future. While we seek to ensure a consistently broad approach, some differences in operational details may apply owing to local regulations.

Can the Number of Radiofrequency Activations Predict Serious Adverse Events after Bronchial Thermoplasty? A Retrospective Case-Control Study

Introduction

Bronchial thermoplasty (BT) is a bronchoscopic procedure that involves the delivery of thermal radiofrequency energy to the bronchial wall for treating severe asthma. It has been suggested that too many radiofrequency activations could induce serious adverse events (SAEs) at an early stage. We aimed to examine the number of radiofrequency activations at each session and early lung function changes from baseline to determine whether these are related to SAEs.

Methods

We retrospectively investigated 13 consecutive patients who underwent three sessions each of BT for severe asthma from February 2015 to January 2016. Lung function tests were performed on the day before and after each BT procedure. Since we compared the number of activations and lung function changes from baseline after each session, a total of 39 sessions were reviewed. The relationship between the number of radiofrequency activations and each lung function change from baseline was also examined by linear regression analysis.

Results

A total of 10 SAEs (4 of pneumonia, 3 of atelectasis, 2 of bronchial asthma exacerbation and 1 of hemoptysis) were observed following the 39 BT sessions. When we compared sessions with and without SAEs, there were no differences in the number of activations (mean ± SD, 71.5 ± 28.6 times in sessions with SAEs; 66.5 ± 25.1 times in sessions without SAEs; p = 0.772) and lung function changes (mean changes in FVC/%FVC/FEV₁/%FEV₁/%PEF from baseline; − 0.49 l/− 14.2%/− 0.36 l/− 11.7%/− 9.6% in sessions with SAEs; − 0.43 l/− 13.3%/− 0.34 l/− 12.1%/− 9.4% in sessions without SAEs; p > 0.05 for all the above). Increase in the number of activations correlated with decreased FEV₁ (R² = 0.17, p = 0.0088) and %FEV₁ (R² = 0.11, p = 0.0357).

Conclusions

Increase in the number of radiofrequency activations during BT is related to a decrease in FEV₁ and %FEV₁ from baseline. The number of radiofrequency activations, however, is not associated with SAEs after BT.

Pulmonary outcomes in adults with a history of Bronchopulmonary Dysplasia differ from patients with asthma

Background

Bronchopulmonary dysplasia (BPD) is a risk factor for respiratory disease in adulthood. Despite the differences in underlying pathology, patients with a history of BPD are often treated as asthmatics. We hypothesized that pulmonary outcomes and health-related quality of life (HRQoL) were different in adults born preterm with and without a history of BPD compared to asthmatics and healthy individuals.

Methods

We evaluated 96 young adults from the LUNAPRE cohort (clinicaltrials.gov/ct2/show/NCT02923648), including 26 individuals born preterm with a history of BPD (BPD), 23 born preterm without BPD (preterm), 23 asthmatics and 24 healthy controls. Extensive lung function testing and HRQoL were assessed.

Results

The BPD group had more severe airway obstruction compared to the preterm-, (FEV₁₋ 0.94 vs. 0.28 z-scores; p ≤ 0.001); asthmatic- (0.14 z-scores, p ≤ 0.01) and healthy groups (0.78 z-scores, p ≤ 0.001). Further, they had increased ventilation inhomogeneity compared to the preterm- (LCI 6.97 vs. 6.73, p ≤ 0.05), asthmatic- (6.75, p = 0.05) and healthy groups (6.50 p ≤ 0.001). Both preterm groups had lower D_LCO compared to healthy controls (p ≤ 0.001 for both). HRQoL showed less physical but more psychological symptoms in the BPD group compared to asthmatics.

Conclusions

Lung function impairment and HRQoL in adults with a history of BPD differed from that in asthmatics highlighting the need for objective assessment of lung health.

Electronic supplementary material

The online version of this article (10.1186/s12931-019-1075-1) contains supplementary material, which is available to authorized users.

Association of Sensitization to Different Aeroallergens With Airway Function and Nasal Patency in Urban Children

PURPOSE

Children with sensitization to aeroallergens have decreased lung function and nasal patency. Our purpose was to determine the association of sensitization to different aeroallergens with airway function and nasal patency.

METHODS

Four hundred and eighty-six randomly selected 11 year-old children who lived in Seongnam City were examined. Serum specific immunoglobulin E (IgE) levels against 6 common allergens (Dermatophagoidesfarinae, birch, cat, dog, Japanese hop and Alternaria), impulse oscillometry (IOS) results for the evaluation of airway dysfunction, and acoustic rhinometry for the determination of nasal airway patency were obtained.

RESULTS

IOS indicated that children sensitized to Alternaria (n = 38, 7.8%) and dog dander (n = 69, 14.2%) had decreased lung function, based on resistance at 10 Hz (Rrs10; aβ = 0.0072; 95% CI, 0.017, 0.127; P = 0.010) and 1 Hz (Rrs1; aβ = 0.038; 95% CI, 0.001, 0.074; P = 0.042). Children sensitized to D. farinae (n = 281, 57.8%) had decreased post-decongestant nasal volume at 0 to 5 cm (aβ = -0.605; 95% CI, -1.005, -0.205; P = 0.003), but normal IOS results at all measured frequencies (P > 0.05). Increased serum eosinophil level was associated with Rrs1 (P = 0.007) and Rrs2 (P = 0.018) and post-decongestant nasal volume at 0 to 5 cm (aβ = -0.885; 95% CI, -1.331, -0.439; P < 0.001).

CONCLUSIONS

Sensitivity to specific aeroallergens, serum eosinophil count and total IgE level had different associations with upper and lower airway dysfunction in urban children.

Contribution of lung function tests to the staging of severe equine asthma syndrome in the field

Staging methods are useful tools for monitoring disease and response to treatment, and because Severe Equine Asthma Syndrome (SEAS) has a high prevalence in the equine population, a clinical staging method can provide important information to optimize equine care. Our team has previously developed and published a clinical staging method for SEAS and in the present study we further evaluated information provided by lung function tests, in order to determine their contribution to disease staging. Using discriminant analysis we set out to produce a new staging method with applicability in the field. Differences between group means (P < .05) were observed for clinical score, bronchoalveolar lavage fluid neutrophil percentage, pleural pressure (ΔPpl), PaO₂ and histamine concentration and the linear functions obtained explained 99.3% of the data variability, with 94.7% of cases grouped correctly and a cross-validation of 86.8%. Thus this staging model showed very good results and the discriminant linear functions may be used to identify and stage SEAS. This method can be used in the field and also in diagnostic and research centres.

The 6-Minute Walk Test as a Tool for Determining Exercise Capacity and Prognosis in Patients with Silicosis

OBJECTIVE

To evaluate exercise capacity using the 6-minute walk test (6MWT) in patients with complicated silicosis, and to determine how results shape the prognostic value of 6MWT for hospitalization and mortality.

METHOD

Prospective observational study in 143 patients with complicated silicosis who performed the 6MWT in our outpatient pulmonology clinic between 2009 and the end of 2016. Lung function tests, computed tomography findings and 6MWT parameters (distance walked and oxygen desaturation) were evaluated.

RESULTS

Patients with complicated silicosis walked 387±92m. Results deteriorated as silicosis severity increased; category A: 407±97m, B: 370±88m, and C: 357±68m (P=.022). The 6MWT correlated positively with lung function and inversely with dyspnea determined by mMRC (P<.001). Patients with moderate/severe emphysema and greater CT90 presented a worse result on 6MWT. Patients who walked<350m had more hospitalizations (3.7±4.0) than those who walked>350m (1.1±2.9). There was an impact on survival: non-survivors walked 327.9±73.0m, while survivors walked 404.5±89.7m (P<.001).

CONCLUSIONS

Spirometry values and category of complicated silicosis correlated with 6MWT and distance walked was a prognostic factor for hospitalization and mortality. The 6MWT is a useful tool in occupational health for monitoring patients with silicosis.

The associations between weight-related anthropometrics during childhood and lung function in late childhood: a retrospective cohort study

Background

An association between body weight in childhood and subsequent lung function and asthma has been suggested, but few longitudinal studies exist. Our aim was to explore whether weight-related anthropometric measurements through childhood were associated with lung function in late childhood.

Methods

From an original nested case-control study, a cohort study was conducted, where lung function was measured in 463 children aged 12.8 years, and anthropometry was measured at several ages from birth through 12.8 years of age. Associations between anthropometrics and lung function were analysed using multiple linear and fractional polynomial regression analysis.

Results

Birthweight and body mass index (BMI; kg/m²) at different ages through childhood were positively associated with forced vital capacity in percent of predicted (FVC %) and forced expiratory volume in the first second in percent of predicted (FEV₁%) at 12.8 years of age. BMI, waist circumference, waist-to-height ratio and skinfolds at 12.8 years of age and the change in BMI from early to late childhood were positively associated with FVC % and FEV₁% and negatively associated with FEV₁/FVC and forced expiratory flow at 25–75% of FVC/FVC. Interaction analyses showed that positive associations between anthropometrics other than BMI and lung function were mainly found in girls. Inverse U-shaped associations were found between BMI at the ages of 10.8/11.8 (girls/boys) and 12.8 years (both genders) and FVC % and FEV₁% at 12.8 years of age.

Conclusions

Weight-related anthropometrics through childhood may influence lung function in late childhood. These findings may be physiological or associated with air flow limitation. Inverse U-shaped associations suggest a differential impact on lung function in normal-weight and overweight children.

Trial registration

This study was observational without any health care intervention for the participants. Therefore, no trial registration number is available.

Electronic supplementary material

The online version of this article (doi: 10.1186/s12890-017-0567-3) contains supplementary material, which is available to authorized users.

The Differences in Spirometry Predictive Equations in Classifying Presence and Degree of Lung Function Impairment: Which Suit Fits the Best?

PURPOSE

The aim of this study was to compare the differences between three most commonly used predictive equations (PE): ECCS (European Community of Coal and Steel), the third National Health and Nutrition Examination Survey (NHANES III), and GLI (Global Lung Initiative) in healthy individuals and when grading severity of lung function impairment in patients with obstructive lung diseases.

METHODS

The study included 200 healthy volunteers and 200 patients with obstructive lung diseases at the Institute for Pulmonary Diseases of Vojvodina. In all subjects, we calculated the absolute and relative (percent) predicted values using ECCS, NHANES III, and GLI reference equations.

RESULTS

The mean differences between ECCS and NHANES III predicted values were 5.63% (95% CI  5.29-5.98%, p < 0.001) for FEV1 and 10% (95% CI 9.52-10.79%, p < 0.001) for FVC. Similar differences were observed between ECCS and GLI predicted values. There were minimal differences between NHANES III and GLI predictive values. In healthy subjects, the mean absolute difference between measured FEV1 and FEV1 ECCS predicted was 0.36l (95% CI 0.32l, 0.40l, p < 0.001), FEV1 NHANES predicted was 0.30 l (95% CI 0.27-0.35l, p < 0.001), and FEV1 GLI predicted was 0.31l (95% CI 0.27- 0.35l, p < 0.001). The use of three different PE leads to significant differences in classification of obstruction severity in both asthma and COPD patients.

CONCLUSIONS

There were significant differences between FEV1 and FVC predicted when using different PE. The absolute difference between actual and predicted FEV1 in healthy individuals was highest when using ECCS. The use of different PE may change the interpretation of severity of airway obstruction.

Lung function development after preterm birth in relation to severity of Bronchopulmonary dysplasia

BACKGROUND

Bronchopulmonary dysplasia (BPD) is a strong risk factor for respiratory morbidity in children born preterm. Our aims were to evaluate lung function in adolescents born preterm with and without a history of BPD, and to assess lung function change over time from school age.

METHODS

Fifty-one individuals born in Stockholm, Sweden between gestational ages 24 to 31 weeks (23 neonatally diagnosed with respiratory distress syndrome (RDS) but not BPD, and 28 graded as mild (n = 17), moderate (n = 7) or severe (n = 4) BPD) were examined in adolescence (13-17 years of age) using spirometry, impulse oscillometry (IOS), plethysmography, and ergospirometry. Comparison with lung function data from school age (6-8 years of age) was also performed.

RESULTS

Adolescents with a history of BPD had lower forced expiratory volume in 1 s (FEV₁) compared to those without BPD (-0.61 vs.-0.02 z-scores, P < 0.05), with lower FEV₁ values significantly associated with BPD severity (P for trend 0.002). Subjects with severe BPD had higher frequency dependence of resistance, R_5-20, (P < 0.001 vs. non-BPD subjects) which is an IOS indicator of peripheral airway involvement. Between school age and adolescence, FEV₁/FVC z-scores decreased in all groups and particularly in the severe BPD group (from -1.68 z-scores at 6-8 years to -2.74 z-scores at 13-17 years, p < 0.05 compared to the non-BPD group).

CONCLUSIONS

Our results of spirometry and IOS measures in the BPD groups compared to the non-BPD group suggest airway obstruction including involvement of peripheral airways. The longitudinal result of a decrease in FEV₁/FVC in the group with severe BPD might implicate a route towards chronic airway obstruction in adulthood.

Cardiorespiratory fitness and sports activities in children and adolescents with solitary functioning kidney

BACKGROUND

An increasing number of children with chronic disease require a complete medical examination to be able to practice physical activity. Particularly children with solitary functioning kidney (SFK) need an accurate functional evaluation to perform sports activities safely. The aim of our study was to evaluate the influence of regular physical activity on the cardiorespiratory function of children with solitary functioning kidney.

METHOD

Twenty-nine patients with congenital SFK, mean age 13.9 ± 5.0 years, and 36 controls (C), mean age 13.8 ± 3.7 years, underwent a cardiorespiratory assessment with spirometry and maximal cardiopulmonary exercise testing. All subjects were divided in two groups: sedentary (S) and trained (T) patients, by means of a standardized questionnaire about their weekly physical activity.

RESULTS

We found that mean values of maximal oxygen consumption (VO2max) and exercise time (ET) were higher in T subjects than in S subjects. Particularly SFK-T presented mean values of VO2max similar to C-T and significantly higher than C-S (SFK-T: 44.7 ± 6.3 vs C-S: 37.8 ± 3.7 ml/min/kg; p < 0.0008). We also found significantly higher mean values of ET (minutes) in minutes in SFK-T than C-S subjects (SFK-T: 12.9 ± 1.6 vs C-S: 10.8 ± 2.5 min; p <0.02).

CONCLUSION

Our study showed that regular moderate/high level of physical activity improve aerobic capacity (VO2max) and exercise tolerance in congenital SFK patients without increasing the risks for cardiovascular accidents and accordingly sports activities should be strongly encouraged in SFK patients to maximize health benefits.

Vocal cord dysfunction diagnosis may be improved by a screening check list

BACKGROUND

Many patients with vocal cord dysfunction (VCD), with or without asthma, receive inappropriate treatment because they are misdiagnosed as having difficult-to-control asthma alone. We developed a clinical screening check list designed to aid the diagnosis of VCD.

METHODS

A prospective observational study involving 80 patients aged ≥18 years, diagnosed with severe asthma. After anamnesis and physical examination, physicians completed a check list with 6 questions to identify VCD, for which the answer "yes" counted one point. Then patients underwent spirometry and laryngoscopy. On the basis of the laryngoscopic findings, we created three patient groups: VCD (vocal cord adduction during inspiration, n = 14); unconfirmed VCD (inconclusive findings, n = 29); and control (normal findings, n = 37). We attempted to determine whether any of those groups were associated with the responses to individual questions or sets of questions on the check list.

RESULTS

The proportion of affirmative answers to the question "Does pulmonary auscultation reveal wheezing, predominantly in the cervical region, and/or stridor?" was significantly higher for the VCD group than for the other two groups (P = 0.006), notably in elderly patients. The variable "4 or more affirmative answers" was more common in VCD and unconfirmed VCD groups in comparison to controls (P = 0.022).

CONCLUSIONS

A finding of wheezing or stridor on auscultation of the cervical region is suggestive of vocal cord dysfunction, especially in elderly patients, and such dysfunction can be confirmed through laryngoscopy. Our VCD screening check list proved to be useful in the screening of VCD among patients with severe asthma.

Anti-Ascaris immunoglobulin E associated with bronchial hyper-reactivity in 9-year-old rural Bangladeshi children

BACKGROUND

Studies have addressed the immunomodulatory effects of helminths and their protective effects upon asthma. However, anti-Ascaris IgE has been reported to be associated with an increased risk of asthma symptoms. We examined the association between serum levels of anti-Ascaris IgE and bronchial hyper-responsiveness (BHR) in children living in rural Bangladesh.

METHODS

Serum anti-Ascaris IgE level was measured and the BHR test done in 158 children aged 9 years selected randomly from a general population of 1705 in the Matlab Health and Demographic Surveillance Area of the International Centre for Diarrhoeal Disease Research, Bangladesh. We investigated wheezing symptoms using a questionnaire from the International Study of Asthma and Allergies in Childhood. BHR tests were successfully done on 152 children (108 'current wheezers'; 44 'never-wheezers'). We examined the association between anti-Ascaris IgE level and wheezing and BHR using multiple logistic regression analyses.

RESULTS

Of 108 current-wheezers, 59 were BHR-positive; of 44 never-wheezers, 32 were BHR-negative. Mean anti-Ascaris IgE levels were significantly higher (12.51 UA/ml; 95% confidence interval (CI), 9.21-17.00) in children with current wheezing with BHR-positive than in those of never-wheezers with BHR-negative (3.89; 2.65-5.70; t test, p < 0.001). A BHR-positive test was independently associated with anti-Ascaris IgE levels with an odds ratio (OR) = 7.30 [95% CI, 2.28-23.33], p = 0.001 when adjusted for total IgE, anti-Dermatophagoides pteronyssinus IgE, pneumonia history, parental asthma, Trichuris infection, forced expiratory volume in one second, eosinophilic leukocyte count, and sex.

CONCLUSIONS

Anti-Ascaris IgE level is associated with an increased risk of BHR among 9-year-old rural Bangladeshi children.

Effects of obesity on lung volume and capacity in children and adolescents: a systematic review

OBJECTIVE

To assess the effects of obesity on lung volume and capacity in children and adolescents.

DATA SOURCE

This is a systematic review, carried out in Pubmed, Lilacs, Scielo and PEDro databases, using the following Keywords: Plethysmography; Whole Body OR Lung Volume Measurements OR Total Lung Capacity OR Functional Residual Capacity OR Residual Volume AND Obesity. Observational studies or clinical trials that assessed the effects of obesity on lung volume and capacity in children and adolescents (0-18 years) without any other associated disease; in English; Portuguese and Spanish languages were selected. Methodological quality was assessed by the Agency for Healthcare Research and Quality.

DATA SYNTHESIS

Of the 1,030 articles, only four were included in the review. The studies amounted to 548 participants, predominantly males, with sample size ranging from 45 to 327 individuals. 100% of the studies evaluated nutritional status through BMI (z-score) and 50.0% reported the data on abdominal circumference. All demonstrated that obesity causes negative effects on lung volume and capacity, causing a reduction mainly in functional residual capacity in 75.0% of the studies; in the expiratory reserve volume in 50.0% and in the residual volume in 25.0%. The methodological quality ranged from moderate to high, with 75.0% of the studies classified as having high methodological quality.

CONCLUSIONS

Obesity causes deleterious effects on lung volume and capacity in children and adolescents, mainly by reducing functional residual capacity, expiratory reserve volume and residual volume.

Effects of obesity on lung volume and capacity in children and adolescents: a systematic review

OBJECTIVE

To assess the effects of obesity on lung volume and capacity in children and adolescents.

DATA SOURCE

This is a systematic review, carried out in Pubmed, Lilacs, Scielo and PEDro databases, using the following Keywords: Plethysmography; Whole Body OR Lung Volume Measurements OR Total Lung Capacity OR Functional Residual Capacity OR Residual Volume AND Obesity. Observational studies or clinical trials that assessed the effects of obesity on lung volume and capacity in children and adolescents (0-18 years) without any other associated disease; in English; Portuguese and Spanish languages were selected. Methodological quality was assessed by the Agency for Healthcare Research and Quality.

DATA SYNTHESIS

Of the 1,030 articles, only four were included in the review. The studies amounted to 548 participants, predominantly males, with sample size ranging from 45 to 327 individuals. 100% of the studies evaluated nutritional status through BMI (z-score) and 50.0% reported the data on abdominal circumference. All demonstrated that obesity causes negative effects on lung volume and capacity, causing a reduction mainly in functional residual capacity in 75.0% of the studies; in the expiratory reserve volume in 50.0% and in the residual volume in 25.0%. The methodological quality ranged from moderate to high, with 75.0% of the studies classified as having high methodological quality.

CONCLUSIONS

Obesity causes deleterious effects on lung volume and capacity in children and adolescents, mainly by reducing functional residual capacity, expiratory reserve volume and residual volume.

Lung function decline over 25 years of follow-up among black and white adults in the ARIC study cohort

BACKGROUND

Interpretation of longitudinal information about lung function decline from middle to older age has been limited by loss to follow-up that may be correlated with baseline lung function or the rate of decline. We conducted these analyses to estimate age-related decline in lung function across groups of race, sex, and smoking status while accounting for dropout from the Atherosclerosis Risk in Communities Study.

METHODS

We analyzed data from 13,896 black and white participants, aged 45-64 years at the 1987-1989 baseline clinical examination. Using spirometry data collected at baseline and two follow-up visits, we estimated annual population-averaged mean changes in forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) by race, sex, and smoking status using inverse-probability-weighted independence estimating equations conditioning-on-being-alive.

RESULTS

Estimated rates of FEV1 decline estimated using inverse-probability-weighted independence estimating equations conditioning on being alive were higher among white than black participants at age 45 years (e.g., male never smokers: black: -29.5 ml/year; white: -51.9 ml/year), but higher among black than white participants by age 75 (black: -51.2 ml/year; white: -26). Observed differences by race were more pronounced among men than among women. By smoking status, FEV1 declines were larger among current than former or never smokers at age 45 across all categories of race and sex. By age 60, FEV1 decline was larger among former and never than current smokers. Estimated annual declines generated using unweighted generalized estimating equations were smaller for current smokers at younger ages in all four groups of race and sex compared with results from weighted analyses that accounted for attrition.

CONCLUSIONS

Using methods accounting for dropout from an approximately 25-year health study, estimated rates of lung function decline varied by age, race, sex, and smoking status, with largest declines observed among current smokers at younger ages.

The geriatric asthma: pitfalls and challenges

Historically, asthma has been envisioned as a disease of younger ages. This has led to the assumption that respiratory symptoms suggestive of asthma occurring in older ages are to be attributed to conditions other than asthma, mainly COPD. Old observational reports and new epidemiological studies confirm that asthma is as frequent in older as it is in younger populations. Nevertheless, under-recognition, misdiagnosis and under-treatment are still relevant issues. The characterization of asthma in the aged suffers from the fact that there has been very little original research in this field. Indeed, geriatric asthma is often excluded from clinical trials because of age and comorbidities. The current review paper revises the areas that need to be elucidated, and highlights the gaps in the management of this condition. It follows that a multidimensional management is advocated for elderly asthmatics to evaluate the severity and establish the complexity of the disease. We suggest that the term “geriatric” asthma should be preferred to “senile” asthma, which is confined to the age-related changes in the lung, or the more generic “asthma in the elderly”, which is only descriptive of the prevalence in specific age groups.

Lung function in pulmonary hypertension

Breathlessness is a common symptom in pulmonary hypertension (PH) and an important cause of morbidity. Though this has been attributed to the well described pulmonary vascular abnormalities and subsequent cardiac remodelling, changes in the airways of these patients have also been reported and may contribute to symptoms. Our understanding of these airway abnormalities is poor with conflicting findings in many studies. The present review evaluates these studies for the major PH groups. In addition we describe the role of cardiopulmonary exercise testing in the assessment of pulmonary arterial hypertension (PAH) by evaluating cardiopulmonary interaction during exercise. As yet, the reasons for the abnormalities in lung function are unclear, but potential causes and the possible role of inflammation are discussed. Future research is required to provide a better understanding of this to help improve the management of these patients.

Pulmonary capillary permeability and pulmonary microangiopathy in diabetes mellitus

Significant increase in permeability surface (PS) in patients with diabetes confirms pulmonary microcirculation damage in these patients.

To study the efficacy and safety of doxophylline and theophylline in bronchial asthma

BACKGROUND

Asthma is a non communicable chronic disease prevalent all over the world. Two commonly used methylxanthines, theophylline and doxofylline were compared in the study in stable asthmatic patients at recommended doses by various spirometric lung function tests with forced expiratory volume at second one (FEVI) between 50 to 80% of predicted FEVI.

MATERIALS AND METHODS

A total of 100 patients were divided in two groups. Group I was administered 300 mg theophylline twice a day and Group II was administered doxofylline 400 mg twice a day orally for six weeks. Spirometric variables symptom score, and adverse effects were recorded at the baseline level and after six weeks of therapy. Data was compared and analysed statistically.

RESULTS

The spirometric values of forced expiratory volume in 1 second (FEVI), forced vital capacity (FVC), and FEV1/FVC showed a statistically significant improvement over base line with the use of both theophylline as well as doxophylline, but were not statistically different from each other. There was a statistically significant improvement in peak expiratory flow rate (PEFR) after six weeks of treatment with doxophylline compared to theophylline. It was found that the doxophylline has a better safety profile as compared to theophylline. Adverse events occurred in a greater proportion of patients in the theophylline group.

CONCLUSION

In the study it was concluded that both theophylline and doxofylline improved the lung function tests and symptoms in patients of mild Bronchial Asthma, but doxofylline has a better profile in terms of safety.

Association between low vitamin D levels and the diagnosis of asthma in children: a systematic review of cohort studies

BACKGROUND

There is conflicting evidence about the association between low vitamin D levels in children and development of asthma in later life. The objective of this study was to systematically review the evidence for an epidemiological association between low serum levels of vitamin D and the diagnosis of asthma in children.

METHODS

We used the Cochrane methodology for conducting systematic reviews. The search strategy included an electronic search of MEDLINE and EMBASE in February 2013. Two reviewers completed, in duplicate and independently, study selection, data abstraction, and assessment of risk of bias.

RESULTS

Of 1081 identified citations, three cohort studies met eligibility criteria. Two studies found that low serum vitamin D level is associated with an increased risk of developing asthma late in childhood, while the third study found no association with either vitamin D2 or vitamin D3 levels. All three studies suffer from major methodological shortcomings that limit our confidence in their results.

CONCLUSIONS

Available epidemiological evidence suggests a potential association between low serum levels of vitamin D and the diagnosis of asthma in children. High quality studies are needed to reliably answer the question of interest.

Lung function indices of children exposed to wood smoke in a fishing port in South-South Nigeria

Children in the warm rain forest are at risk of having their lung function compromised by a variety of factors, including smoke from wood fires. A total of 358 children from a fishing port and 400 children living in a farm settlement were tested to determine their peak expiratory flow rate (PEFR), forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC), forced expiratory volume in 1 s per cent and forced expiratory flow between 25 and 75%. The values for the PEFR, FVC, FEV1, forced expiratory volume in 1 s per cent and forced expiratory flow between 25 and 75% of the subjects were significantly lower than those of the controls (P value for males = <0.001, 0.01, 0.002, 0.01 and <0.001, respectively, whereas for their female counterparts = <0.001, 0.003, 0.001, 0.04 and <0.001, respectively). These deficits were observed to be more with increasing duration of exposure to wood smoke for PEFR, FVC and FEV1. Chronic exposure to fish drying using firewood can impair lung function in children. There is a need for alternative methods of fish preservation for those engaged in fish drying.

Influence of radiological emphysema on lung function test in idiopathic pulmonary fibrosis

INTRODUCTION

Idiopathic pulmonary fibrosis (IPF) is one of the most frequent interstitial lung disease. Emphysema can be associated with IPF as described in the «Combined pulmonary fibrosis and emphysema» syndrome.

AIM

The primary endpoint of this retrospective cohort study was to evaluate the impact of the association of IPF and emphysema on lung function tests parameters (FVC, TLC, FEV1, FEV1/FVC and DLCO). The secondary endpoint was to assess the impact of the associated radiological emphysema on lung function parameters used in the du Bois prognostic score recently developed by Ron du Bois et al.

METHOD

We retrospectively reviewed the medical files of 98 patients with lung fibrosis who were followed in our University Hospital with access to pharmacological studies and lung transplantation from 1981 to 2011. Fifty six patients were considered for analysis. The collected data included gender, age, smoking history and respiratory hospitalizations. We also analysed their pulmonary functional parameters along with radiological characteristics, in particular the presence of emphysema which was assessed on thoracic high resolution CT scan. The du Bois score was retrospectively calculated from these data.

RESULTS

TLC and FVC at diagnosis were significantly higher in the IPF-E group compared to the IPF group (respectively 86.6 ± 17.2% pv versus 72.0 ± 15.0% pv; p: 0.004 and 86.8 ± 18.4% pv versus 72.6 ± 20.6% pv; p: 0.020). The [Formula: see text] used in the calculation of the du Bois prognostic score was significantly higher in the IPF-E group. By cons, [Formula: see text] was not statistically different between the two groups.

CONCLUSION

Radiological emphysema associated with IPF had an impact on pulmonary function tests. Despite this difference, the du Bois score was not statistically different between these two groups. Nevertheless, after one year of follow up, the patients with emphysema were in a subclass with a lower mortality rate than those without emphysema.

The relationships between tracheal index and lung volume parameters in mild-to-moderate COPD

BACKGROUND

Although elongated morphological changes in the trachea are known to be related to lung function in chronic obstructive pulmonary disease (COPD), whether the tracheal morphological changes are associated with airflow limitations or overinflation of the lung in the early stages of COPD has not yet been determined. Thus, our aim was to investigate the association of tracheal index (TI) with lung function parameters, including lung volume parameters, in COPD patients with mild-to-moderate airflow limitations.

MATERIALS AND METHODS

A retrospective study was conducted in 193 COPD patients with GOLD grades 1-2 (post-bronchodilator forced expiratory volume in 1s [FEV1] ≥ 50% predicted with FEV1/forced vital capacity ratio ≤ 70%; age range, 40-81) and 193 age- and gender-matched subjects with normal lung function as a control group (age range, 40-82). Two independent observers measured TI at three anatomical levels on chest radiographs and CT scans.

RESULTS

Compared with the control group, TI was reduced significantly and "saber-sheath trachea" was observed more frequently in COPD patients. Patients with GOLD grade 2 disease had a lower TI than those with GOLD grade 1. TI had apparent inverse correlations with total lung capacity, functional residual capacity, and residual volume, regardless of the anatomical level of the trachea. Even after adjustments for covariates, this association persisted.

CONCLUSIONS

TI is reduced even in mild-to-moderate COPD patients, and TI measured on chest CT shows significant inverse relationships with all lung volume parameters assessed, suggesting that tracheal morphology may change during the early stages of COPD.

Pulmonary outcome and its correlates in school-aged children born with a gestational age ≤ 32 weeks

BACKGROUND

There is limited data regarding factors influencing the respiratory outcome at school age of ex-preterms born since the introduction of antenatal steroids, surfactant replacement together with less aggressive ventilation.

OBJECTIVES

To establish the main antenatal, neonatal and early childhood respiratory correlates of respiratory status in school-aged children born at ≤ 32 weeks of gestation.

METHODS

Ex-preterm children born at ≤ 32 weeks of gestation between 1997 and 2001 at Bordeaux University Hospital were evaluated at school age, using a respiratory questionnaire and lung function tests (spirometry, plethysmography, exercise challenge test and CO lung diffusing capacity DLCO measurements). Factors associated with lung function were investigated using polynomial regression analyses.

RESULTS

Of the 151 included children [mean age: 8.6 ± 0.8 years; mean gestational age, 30.1 ± 1.7 weeks; mean birth weight = 1310 ± 380 g; 68.2% ventilated at birth; 46.4% treated with surfactant; 36.4% with prior bronchopulmonary dysplasia (BPD)], 47% presented obstructive lung abnormalities, 11% restrictive or mixed lung abnormalities, 41% exercise-induced bronchoconstriction, and 15.5% reduced DLCO. Surfactant therapy was independently associated with a lower risk of lung abnormalities (p < 0.05). The association between BPD and lung abnormalities at school age was not significant, but prior BPD increased the risk of restrictive or mixed abnormalities (odds ratio: 6.11, confidence interval [1.1; 33.99]). Early childhood respiratory events were not associated with the occurrence of lung abnormalities.

CONCLUSION

Children born at ≤ 32 weeks of gestation remain at risk for impaired lung function at school age in particular when they did not receive surfactant. Restrictive or mixed lung defects are mainly associated with prior BPD.

Reference values for spirometry in preschool children

OBJECTIVES

Reference values for lung function tests differ in samples from different countries, including values for preschoolers. The main objective of this study was to derive reference values in this population.

METHODS

A prospective study was conducted through a questionnaire applied to 425 preschool children aged 3 to 6 years, from schools and day-care centers in a metropolitan city in Brazil. Children were selected by simple random sampling from the aforementioned schools. Peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volumes (FEV1, FEV0.50), forced expiratory flow (FEF25-75) and FEV1/FVC, FEV0.5/FVC and FEF25-75/FVC ratios were evaluated.

RESULTS

Of the 425 children enrolled, 321 (75.6%) underwent the tests. Of these, 135 (42.0%) showed acceptable results with full expiratory curves and thus were included in the regression analysis to define the reference values. Height and gender significantly influenced FVC values through linear and logarithmic regression analysis. In males, R(2) increased with the logarithmic model for FVC and FEV1, but the linear model was retained for its simplicity. The lower limits were calculated by measuring the fifth percentile residues.

CONCLUSION

Full expiratory curves are more difficult to obtain in preschoolers. In addition to height, gender also influences the measures of FVC and FEV1. Reference values were defined for spirometry in preschool children in this population, which are applicable to similar populations.

Effects of Sodium Cromoglycate on Iranian Asthmatic Subjects Without Exposure to any Bronchoconstrictor agent

Cromolyn sodium, a mast cell stabilizing agent, provides an immediate protective effect against the exercise-induced bronchoconstriction while being used before the exercise. However, cromolyn is ineffective in reversing asthmatic bronchospasm; it is used as a maintenance therapy and has a prophylactic role in chronic asthma. The purpose of this study was to determine the extent of change in baseline lung function tests following a single dose of cromolyn sodium in adult asthmatics. Forty volunteers (33 women and 7 men) with moderate to severe persistent asthma were randomly assigned to receive 20 mg cromolyn, 40 mg cromolyn or cromolyn-placebo. The percent of improvement in lung function parameters was compared among the groups, during 1 h of inhalation. Low dose of cromolyn induced more improvement in most lung function parameters such as forced expiratory flow volume in one second, forced vital capacity and peak expiratory flow compared with other groups. After 15 min, the improvement percentage of baseline forced expiratory flow volume in one second was 3.35 ± 1.5, for sodium cromoglycate-20 mg group compared with 0.98 ± 1.43 and - 0.68 ± 1.2 for sodium cromoglycate-placebo and sodium cromoglycate-40 mg, groups respectively. However, the differences between means were not significant. Furthermore, based on the definition of American Thoracic Society (ATS) for a "significant post-bronchodilator response" developed in a few patients 15 min after the inhalation of 20 mg cromolyn sodium. It is suggested that probably the inhalation of 20 mg of cromolyn sodium could immediately improve the lung function in few adults with asthma.

Analysis of lung function tests at a teaching hospital

OBJECTIVE

To report on the proportions of restrictive, obstructive and combined types of respiratory diseases in patients referred to respiratory units at the Korle Bu Teaching Hospital.

METHOD

This was a retrospective study of lung function test (LFT) data on patients who were referred from clinics both in and outside KBTH. A spirometer was used to assess various lung volume parameters.

RESULTS

One quarter of total subjects (25.5%) had obstructive, 14.8% restrictive and 11.7% exhibited combined forms of respiratory disease. The rest showed none of the above conditions and were classified as normal. We also found differences in proportions of the disorders for subjects in different age and weight categories. Whereas obstructive respiratory disease occurred more in obese patients, and patients who were 35 years and above, restrictive and combined respiratory diseases occurred more in underweight patients, and patients below age 35 years. The respiratory diseases suggested in our study were found not to be sex-dependent.

CONCLUSION

Our study indicates that obstructive lung disease was the most predominant respiratory lung ailment among patients referred to the respiratory units of Korle Bu Teaching Hospital.