Occupational Risk Factors for COPD Phenotypes in the Multi-Ethnic Study of Atherosclerosis (MESA) Lung Study

Introduction: The contribution of occupational exposure to the risk of chronic obstructive pulmonary disease COPD in population-based studies is of interest. We compared the performance of self-reported exposure to a newly developed JEM in exposure-response evaluation. Methods: We used cross-sectional data from Multi-Ethnic Study of Atherosclerosis (MESA), a population-based sample of 45–84 year olds free of clinical cardiovascular disease at baseline. MESA ascertained the most recent job and employment, and the MESA Lung Study measured spirometry, and occupational exposures for 3686 participants. Associations between health outcomes (spirometry defined airflow limitation and Medical Research Council-defined chronic bronchitis) and occupational exposure [self-reported occupational exposure to vapor-gas, dust, or fumes (VGDF), severity of exposure, and a job-exposure matrix (JEM)-derived score] were evaluated using logistic regression models adjusted for non-occupational risk factors. Results: The prevalence of airflow limitation was associated with self-reported exposure to vapor-gas (OR 2.6, 95%CI 1.1–2.3), severity of VGDF exposure (P-trend < 0.01), and JEM dust exposure (OR 2.4, 95%CI 1.1–5.0), and with organic dust exposure in females; these associations were generally of greater magnitude among never smokers. The prevalence of chronic bronchitis and wheeze was associated with exposure to VGDF. The association between airflow limitation and the combined effect of smoking and VGDF exposure showed an increasing trend. Self-reported vapor-gas, dust, fumes, years and severity of exposure were associated with increased prevalence of chronic bronchitis and wheeze (P < 0.001). Conclusions: Airflow limitation was associated with self-reported VGDF exposure, its severity, and JEM-ascertained dust exposure in smokers and never-smokers in this multiethnic study.     

Oscillometric and spirometric bronchodilator response in preschool children with and without asthma

BACKGROUND:

Bronchodilator responses (BDR) are routinely used in the diagnosis and management of asthma; however, their acceptability and repeatability have not been evaluated using quality control criteria for preschool children.

OBJECTIVES:

To compare conventional spirometry with an impulse oscillometry system (IOS) in healthy and asthmatic preschool children.

METHODS:

Data from 30 asthmatic children and 29 controls (two to six years of age) who underwent IOS and spirometry before and after salbutamol administration were analyzed.

RESULTS:

Stable asthmatic subjects significantly differed versus controls in their spirometry-assessed BDR (forced expiratory volume in 1 s [FEV₁], forced vital capacity and forced expiratory flow at 25% to 75% of forced vital capacity) as well as their IOS-assessed BDR (respiratory resistance at 5 Hz [Rrs₅], respiratory reactance at 5 Hz and area under the reactance curve). However, comparisons based on the area under the ROC curve for ΔFEV₁ % initial versus ΔRrs₅ % initial were 0.82 (95% CI 0.71 to 0.93) and 0.75 (95% CI 0.62 to 0.87), respectively. Moreover, the sensitivity and specificity for ΔFEV₁ ≥9% were 0.53 and 0.93, respectively. Importantly, sensitivity increased to 0.63 when either ΔFEV₁ ≥9% or ΔRrs₅ ≥29% was considered as an additional criterion for the diagnosis of asthma.

CONCLUSION:

The accuracy of asthma diagnosis in preschool children may be increased by combining spirometry with IOS when measuring BDR.     

Utility of bronchodilator response for asthma diagnosis in Latino preschoolers

BackgroundAsthma diagnosis in preschoolers is mostly based on clinical evidence, but a bronchodilator response could be used to help confirm the diagnosis. The objective of this study is to evaluate the utility of bronchodilator response for asthma diagnosis in preschoolers by using spirometry standardised for this specific age group.MethodsA standardised spirometry was performed before and after 200 mcg of salbutamol in 64 asthmatics and 32 healthy control preschoolers in a case-control design study.ResultsThe mean age of the population was 4.1 years (3–5.9 years) and 60% were females. Almost 95% of asthmatics and controls could perform an acceptable spirometry, but more asthmatics than controls reached forced expiratory volume in one second (FEV₁) (57% vs. 23%, p = 0.033), independent of age. Basal flows and FEV₁ were significantly lower in asthmatics than in controls, but no difference was found between groups in forced vital capacity (FVC) and FEV in 0.5 s (FEV_0.5). Using receiver operating characteristic (ROC) curves, the variable with higher power to discriminate asthmatics from healthy controls was a bronchodilator response (% of change from basal above the coefficient of repeatability) of 25% in forced expiratory flow between 25% and 75% (FEF_25–75) with 41% sensitivity, 80% specificity. The higher positive likelihood ratio for asthma equalled three for a bronchodilator response of 11% in FEV_0.5 (sensitivity 30%, specificity 90%).ConclusionsIn this sample of Chilean preschoolers, spirometry had a very high performance and bronchodilator response was very specific but had low sensitivity to confirm asthma diagnosis.     

The Effectiveness and Harms of Screening for Chronic Obstructive Pulmonary Disease: An Updated Systematic Review and Meta-Analysis

BackgroundThis study aimed to perform meta-analyses to update a previous systematic review (SR) conducted by the US Preventive Services Task Force (USPSTF) to evaluate the benefits and harms of screening for chronic obstructive pulmonary disease (COPD) in asymptomatic adults.MethodsMEDLINE, EMBASE, Cochrane Library, and regional databases were searched from their inception to January 2020. Studies for diagnostic accuracy, preventive services effect, treatment efficacy, and treatment harms were included.ResultsEighteen studies were included, and twelve of these were newly added in this update. In meta-analyses, the pooled sensitivity and specificity for COPD diagnosis using spirometry were 73.4% and 89.0%, respectively. The relative effect of smoking cessation intervention with screening spirometry, presented as abstinence rate, was not statistically significant (risk ratio [RR], 1.21; 95% confidence interval [CI], 0.87–1.67) when all selected studies were pooled, but screening on smoking cessation was effective (RR, 1.58; 95% CI, 1.14–2.19) when limited to studies with smoking cessation programs that provided smoking cessation medicines or intensive counseling at public health centers or medical institutions.ConclusionIn this study, no direct evidence for the impact on health outcomes of screening asymptomatic adults for COPD was identified similar to the previous SR. Further research is necessary to confirm the benefits of COPD screening.     

The Utility of Spirometry in Diagnosing Pulmonary Restriction

The aim of this retrospective study was to determine the utility of the spirometric measurements FVC, FEV₁, and FEV₁/FVC in diagnosing pulmonary restriction. Spirometry and lung volume measurements performed on the same patient visit were analyzed. The sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of (1) FVC < lower limit of normal (LLN) (NHANES III reference values) and (2) FVC < LLN and FEV₁/FVC ≥ LLN were compared to diagnose restriction based on lung volume measurements. In all, 18,282 pulmonary function tests from 8,315 patients were analyzed. Twenty-six percent of the patients (n = 2,213) had restriction based on lung volume measurements. The sensitivity, specificity, PPV, and NPV of FVC < LLN to diagnose restriction based on lung volume measurement criteria were 88.6%, 56.8%, 39.9%, and 93.9%, respectively. The sensitivity, specificity, PPV, and NPV of FVC < LLN and FEV₁/FVC ≥ normal to diagnose restriction based on lung volume criteria were 72.4%, 87.1%, 64.4%, and 90.7%, respectively. Analysis of ROC curves showed that spirometric criteria based on FVC alone performed better (area under the curve = 0.817) than those based on the combined criteria of FVC and FEV₁/FVC (area under the curve = 0.584). Consistent with earlier findings, the negative predictive value for a normal FVC (≥ LLN) to exclude pulmonary restriction was high in this series (up to 95.7%). Also, a spirometric diagnosis of “restriction” (FVC < LLN and FEV₁/FVC ≥ LLN) had a positive predictive value of 26.3–73.9%. On this basis, normal FVC can be regarded as excluding restriction with high reliability. Saiprakash B. Venkateshiah and Octavian C. Ioachimescu authors contributed equally to this work.     

Relationship between impulse oscillometry and spirometric indices in cystic fibrosis children

Background: The aim of our retrospective study was to determine the relationship between impulse oscillometry ( IOS) data and spirometric tests in cystic fibrosis (CF) children.
Methods : Thirty CF children aged 4–19 years have performed lung function tests (LFT). A subset of 15 patients repeated LFT on five separate occasions. IOS parameters were respiratory resistance (Rrs), reactance (Xrs) and impedance at 5 Hz (R5, X5, Zr) and the resonant frequency (Fres). Spirometry indices (SI) included forced expiratory volume in 1 sec (FEV₁), forced expiratory flow during the middle half of FVC (FEF_25–75) and forced vital capacity (FVC).
Results: An inverse relationship was observed between raw values of R5, Zr, Fres and SI respectively, and X5 correlated positively with SI. Although significant, these correlations were poor. Receiver operating characteristic curves (ROC) were constructed to identify cutoff points for IOS parameters to discriminate between children according to predefined FEV₁ thresholds (percent predicted), generally used to categorize the level of lung function impairment. No acceptable cutoff points can be found for IOS parameters. Trends analyses in the subgroup of 15 patients showed a significant decline of FEV₁ between the first and the fifth evaluation. None of the IOS indices demonstrated a consistent tendency, apart from a slight decrease of Fres.
Conclusion: IOS measurements presented an insufficient sensitivity to detect and follow bronchial obstruction in CF patients.     

维生素D血浆浓度与氟替卡松对COPD患者肺功能的影响

目的探讨25-羟维生素D血浆浓度与吸人性糖皮质激素对COPD患者肺功能影响的关系。方法120例重度COPD患者于初人院时进行气量测定以及清晨禁食采集血样标本，用高效液相色谱法检测25（OH）D水平；而后每日2次，每次使用500μg氟替卡松，50μg沙美特罗，疗程4周。4周后再检测第1秒用力通气量及其改变，抽取血样，检测25（OH）D水平。治疗前后测量第1秒用力呼气容积（FEV1），与25（OH）D血浆水平进行相关性分析。结果25（OH）D血浆浓度水平平均为（23．3±9．3）ng/mL．在COPD患者中普遍维生素D缺乏，约占40％。对氟替卡松起效的患者体内25（OH）D水平偏高，在使用氟替卡松4周后，第1秒用力通气量有明显改善。结论25（OH）D血浆水平与患者对氟替卡松的敏感性有关，并可提高第1秒用力通气量，提高1秒率，改善肺功能。     

Clara cell protein and surfactant protein B in garbage collectors and in wastewater workers exposed to bioaerosols

Objectives: Inhalation of bioaerosols has been hypothesised to cause toxic pneumonitis that should increase lung epithelial permeability at the bronchioloalveolar level. Serum Clara cell protein (CC16) and serum surfactant protein B (SPB) have been proposed as sensitive markers of lung epithelial injury. This study was aimed at looking for increased lung epithelial permeability by determining CC16 and SPB in workers exposed to bioaerosols from wastewater or garbage. Methods: Subjects (778 wastewater, garbage and control workers; participation 61%) underwent a medical examination, lung function tests [American Thoracic Society (ATS) criteria], and determination of CC16 and SPB. Symptoms of endotoxin exposure and several potential confounders (age, gender, smoking, kidney function, obesity) were looked for. Results were examined with multiple linear or logistic regression. Results: Exposure to bioaerosols increased CC16 concentration in the wastewater workers. No effect of exposure on SPB was found. No clue to work-related respiratory diseases was found. Conclusions: The increase in CC16 in serum supports the hypothesis that bioaerosols cause subclinical toxic pneumonitis, even at low exposure.     

Combined body plethysmographic, spirometric and flow volume reference values for male and female children aged 6 to 16 years obtained from “hospital normals”

Vital capacity (VC) and its subdivisions (IC and ERV), total lung capacity (TLC), residual volume (RV), peak expiratory flow (PEF), forced vital capacity (FVC), forced expiratory volume in one second (FEV₁), maximum flow volume curve (MEF₇₅, MEF₅₀, MEF₂₅, MMEF, FEF_75–85), airway resistance (R_tot, R_eff) and the thoracic gas volume at resting expiratory position (FRC) were measured in 187 girls and 213 boys (hospital normals) aged 6 to 16 years. The measurements were carried out consecutively on the same subjects in the morning using a volume-constant plethysmograph (MasterLab, E. Jaeger; programs: body plethysmography, spirometry and flow volume). Using multiple regression analysis the best fitting curves for the prediction of normal values for boys and girls were selected. Analyses of covariance were performed to compare the adjusted means of the spirometric and body plethysmographic variables of the male and female subjects. As expected, we found higher static and dynamic (FVC, FEV₁, PEF) lung volumes in boys than in girls relating to height. The flows (MMEF, MEF₅₀, MEF₂₅, FEF_75–85) were significantly lower in the male than in the female subjects of the same age justifying separate prediction equations, but the same equation for both genders may be used for the resistance variables R_tot and R_eff. Our results are compared with those of previous studies. Conclusion Lung volumes and flows differ significantly between girls and boys calling for separate reference values for female and male subjects of the same age. Received: 21 August 2000 and in revised form: 20 December 2000 / Accepted: 22 December 2000