Reference values of spirometry for Finnish adults

The prevalence of respiratory symptoms and diseases and declined lung function among foundry workers

BACKGROUND

Foundry workers are occupationally exposed to a variety of inhalable chemical substances. Occupational exposure to vapors, gases, dusts, and fumes can lead to adverse health effects on the respiratory system and cause chronic respiratory diseases, such as interstitial lung diseases (ILDs), chronic obstructive lung disease (COPD), chronic bronchitis, and emphysema. Research on respiratory symptoms, diseases, and lung function in foundry workers over the past few decades has been limited. The aim of this cross-sectional study was to assess the prevalence of respiratory symptoms and diseases and declined lung function of current foundry workers, ex-foundry workers, and unexposed controls.

METHODS

We assessed respiratory symptoms, diseases, and lung function among 335 current foundry workers, 64 ex-foundry workers, and 161 unexposed controls. The cumulative dust exposure (mg-y) of each participant was calculated, and the median cumulative dust exposure according to the main places of exposure was determined.

RESULTS

A higher prevalence of chronic bronchitis, as reported in a questionnaire, was found among current and ex-foundry workers compared to unexposed controls, even after adjusting for pack-years of smoking (p = 0.009). Additionally, cough and wheezing in adulthood without respiratory infection, and chronic rhinitis symptoms were more common among current and ex-foundry workers compared to unexposed controls. These differences remained significant even after adjusting for pack-years of smoking and body mass index (BMI) (p = 0.007 and p  < 0.001, respectively). Impaired lung function was more prevalent among both ex-foundry workers (29.7%) and current foundry workers (15.5%) compared to the unexposed controls (8.7%), with the difference remaining significant even after adjusting for the pack-years of smoking and BMI (p = 0.009). According to the questionnaire, the number of physician-diagnosed cases of chronic obstructive pulmonary disease (COPD) or chronic bronchitis was unexpectedly low compared to the indications from the symptom questionnaire and lung function test results, suggesting a potential underdiagnosis. The prevalence of silicosis was low (0.8%) among current and ex-foundry workers.

CONCLUSIONS

Respiratory symptoms are common among foundry workers. Current and ex-foundry workers exhibited lower lung function in spirometry compared to unexposed controls. There is a potential underdiagnosis of COPD and chronic bronchitis among foundry workers.

Outcome-based Definition of the Lower Limit of Normal in Spirometry: A Study of 26,000 Young Adult Men

Rationale: The definition of the lower limit of normal (LLN) of spirometric variables is not well established. Objectives: To investigate the relationship between spirometric abnormalities defined with different thresholds of the LLN and clinical outcomes and to explore the possibility of using different LLN thresholds according to the pretest probability of disease. Methods: We studied the associations between prebronchodilator spirometric abnormalities (forced expiratory volume in the first second [FEV1] < LLN, forced vital capacity [FVC] < LLN, airflow obstruction, spirometric restriction) defined with different thresholds of the LLN (10th, 5th, 2.5th, 1st percentile) and multiple outcomes (prevalence of spirometric abnormalities, respiratory symptoms, all-cause and respiratory mortality) in 26,091 30- to 46-year-old men who participated in a general population survey in Norway in 1988-1990 and were followed for 26 years. Analyses were performed with both local and Global Lung Function Initiative (GLI)-2012 reference equations, stratified by pretest risk (presence or absence of respiratory symptoms), and adjusted for age, body mass index, smoking, and education. Results: In the total population, the prevalence of airflow obstruction was 11.6% with GLI-LLN10, 11.0% with Local-LLN5, 6.1% with GLI-LLN5, 7.6% with Local-LLN2.5, and 3.5% with GLI-LLN2.5. The prevalence of spirometric restriction was 5.9% with GLI-LLN10, 5.2% with Local-LLN5, and 2.8% with GLI-LLN5. Increasingly lower thresholds of the LLN were associated with increasingly higher odds of respiratory symptoms and hazard of mortality for all spirometric abnormalities with both reference equations. Spirometric abnormalities defined with Local-LLN2.5 in asymptomatic subjects were associated with lower hazard of all-cause mortality (hazard ratio [HR], 1.50; 95% confidence interval [CI], 1.15-1.95 for FEV1 < LLN) than those defined with Local-LLN5 in the general population (HR, 1.67; 95% CI, 1.50-1.87 for FEV1 < LLN) and symptomatic subjects (HR, 1.67; 95% CI, 1.46-1.91 for FEV1 < LLN). Overall, the prevalence of spirometric abnormalities and associations with outcomes obtained with Local-LLN5 were comparable to those obtained with GLI-LLN10 and those obtained with Local-LLN2.5 to GLI-LLN5. Conclusions: There is a relationship between statistically based thresholds of the LLN of spirometric variables and clinical outcomes. Different thresholds of the LLN may be used in different risk subgroups of subjects, but the choice of the threshold needs to be evaluated together with the choice of reference equations.

Cardiopulmonary exercise testing in long covid shows the presence of dysautonomia or chronotropic incompetence independent of subjective exercise intolerance and fatigue

BACKGROUND

After COVID-19 infection, 10-20% of patients suffer from varying symptoms lasting more than 12 weeks (Long COVID, LC). Exercise intolerance and fatigue are common in LC. The aim was to measure the maximal exercise capacity of the LC patients with these symptoms and to analyze whether this capacity was related to heart rate (HR) responses at rest and during exercise and recovery, to find out possible sympathetic overactivity, dysautonomia or chronotropic incompetence.

METHODS

Cardiopulmonary exercise test was conducted on 101 LC patients, who were admitted to exercise testing. The majority of them (86%) had been treated at home during their acute COVID-19 infection. Peak oxygen uptake (VO2peak), maximal power during the last 4 min of exercise (Wlast4), HRs, and other exercise test variables were compared between those with or without subjective exercise intolerance, fatigue, or both.

RESULTS

The measurements were performed in mean 12.7 months (SD 5.75) after COVID-19 infection in patients with exercise intolerance (group EI, 19 patients), fatigue (group F, 31 patients), their combination (group EI + F, 37 patients), or neither (group N, 14 patients). Exercise capacity was, in the mean, normal in all symptom groups and did not significantly differ among them. HRs were higher in group EI + F than in group N at maximum exercise (169/min vs. 158/min, p = 0.034) and 10 min after exercise (104/min vs. 87/min, p = 0.028). Independent of symptoms, 12 patients filled the criteria of dysautonomia associated with slightly decreased Wlast4 (73% vs. 91% of sex, age, height, and weight-based reference values p = 0.017) and 13 filled the criteria of chronotropic incompetence with the lowest Wlast4 (63% vs. 93%, p < 0.001), VO2peak (70% vs. 94%, p < 0.001), the lowest increase of systolic blood pressure (50 mmHg vs. 67 mmHg, p = 0.001), and the greatest prevalence of slight ECG-findings (p = 0.017) compared to patients without these features. The highest prevalence of chronotropic incompetence was seen in the group N (p = 0.022).

CONCLUSIONS

This study on LC patients with different symptoms showed that cardiopulmonary exercise capacity was in mean normal, with increased sympathetic activity in most patients. However, we identified subgroups with dysautonomia or chronotropic incompetence with a lowered exercise capacity as measured by Wlast4 or VO2peak. Subjective exercise intolerance and fatigue poorly foresaw the level of exercise capacity. The results could be used to plan the rehabilitation from LC and for selection of the patients suitable for it.

Complete blood count, coagulation biomarkers, and lung function 6 months after critical COVID-19

BACKGROUND

Understanding the recovery of post-COVID-19 organ dysfunction is essential. We evaluated coagulation 6 months post-COVID-19, examining its recovery and association with lung function.

METHODS

Patients treated for COVID-19 at intensive care units between 3/2020 and 1/2021 were analyzed for complete blood count (CBC) and coagulation biomarkers (prothrombin time activity (%) (PT%), activated partial thromboplastin time (APTT), fibrinogen, coagulation factor VIII (FVIII), antithrombin (AT), and D-dimer) during the 6 months post-hospitalization. Results were compared with acute phase values and correlated with pulmonary function tests (PFT), including forced vital capacity (FVC) and hemoglobin-corrected diffusing capacity percentage of predicted (DLCOc%), recorded 6 months post-hospitalization. We examined the association between coagulation biomarkers and DLCOc% using linear regression with age, sex, and invasive mechanical ventilation (IMV) duration, and FVIII (correlated with DLCOc%) as covariates.

RESULTS

Most CBCs and coagulation biomarkers had median values within the normal range. However, only 21% (15/70) of patients achieved full normalization of all biomarkers. Compared to acute COVID-19, hemoglobin, PT%, and AT increased, while leukocytes, fibrinogen, FVIII, and D-dimer decreased. Despite decreased levels, FVIII remained elevated in 46% (31/68), leukocytes in 26% (18/70), and D-dimer in 27% (18/67) at 6 months. A weak negative correlation (r = -0.37, p = .036) was found between DLCOc% and FVIII. Multivariable analysis revealed a weak, independent association between DLCOc% and FVIII. Excluding patients with anticoagulation therapy, FVIII no longer correlated with DLCOc%, while AT showed a moderate correlation with DLCOc%.

CONCLUSION

Only a few patients had normal CBC and coagulation biomarker values 6 months after critical COVID-19. A weak negative correlation between DLCOc% and FVIII suggests that deranged coagulation activity may be associated with reduced diffusing capacity.

The link between early childhood lower airway symptoms, airway hyperresponsiveness, and school-age lung function

BACKGROUND

The role of early airway hyperresponsiveness (AHR) in the lung function of school-age children is currently unclear.

OBJECTIVE

To conduct a prospective follow-up study of lung function in schoolchildren with a history of lower airway symptoms and AHR to methacholine in early childhood and to compare the findings to schoolchildren with no previous or current lung diseases. We also explored symptoms and markers of type 2 inflammation.

METHODS

In 2004 to 2011, data on atopic markers, lung function, and AHR to methacholine were obtained from 193 symptomatic children under 3 years old. In 2016 to 2018, a follow-up sample of 84 children (median age, 11 years; IQR, 11-12) underwent measurements of atopic parameters, lung function, and AHR to methacholine. Moreover, in 2017 to 2018, 40 controls (median age, 11 years; IQR, 9-12) participated in the study.

RESULTS

Schoolchildren with early childhood lower airway symptoms and increased AHR had more frequent blood eosinophilia than their peers without increased AHR and lower prebronchodilator forced expiratory volume in 1 second (FEV1) and FEV1/forced vital capacity Z-scores than those without increased AHR and controls. Post-bronchodilator values were not significantly different between the two AHR groups. Atopy in early childhood (defined as atopic eczema and at least 1 positive skin prick test result) was associated with subsequent lung function and atopic markers, but not AHR.

CONCLUSION

In symptomatic young children, increased AHR was associated with subsequent obstructive lung function, which appeared reversible by bronchodilation, and blood eosinophilia, indicative of type 2 inflammation.

Effects of low workload respiratory training with steam inhalation on lung function in stable asthma: A controlled clinical study

To investigate effects of low workload respiratory muscle training (RMT) on respiratory muscle power and lung function in asthmatics, we recruited asthmatic persons who performed a 4-week training programme. The training included 20 daily ex- and inhalations with counter pressure 30% from the individual maximal expiratory pressure (MEP). Lung function was measured before and after the training programme and a follow-up period. The study also included several subjective endpoints for respiratory symptoms. A significant increase in a training group (n = 27) compared with a control group (n = 20) was seen in MEP (+12.4%, vs. +3.5%, p = 0.086), maximal inspiratory pressure (MIP) (+21.1% vs. +0.82%, p = 0.023), slow vital capacity (VC) (+3.7% vs. +1.5%, p = 0.023) and in forced expiratory time (FET, +15.5%, vs. -5.0%, p = 0.022). After being a control for group A, also group B performed similar RMT as group A. In the combined group (A and B, n = 47) MEP (11.3%, p = 0.003), MIP (19.73%, p < 0.001), VC (4.1%, p < 0.001) and FET (14.7%, p < 0.001) increased significantly from the baseline. Changes in other lung function variables were not indicative. On a scale of 1-5, the subjects perceived improvement in reduction of mucus secretion in the airways (median 3, p < 0.001), alleviation of coughing (median 3, p < 0.001) and reduction in dyspnoea (median 3, p < 0.001). As a conclusion, low workload respiratory training of 4 weeks improved respiratory muscle power and increased VC in patients with stable asthma.

Persisting symptoms common but inability to work rare: a one-year follow-up study of Finnish hospitalised COVID-19 patients

BACKGROUND

Difficulties in recovery persisting for months have been reported in patients with severe COVID-19. Our aim was to investigate respiratory and overall recovery one year after hospital discharge.

METHODS

Finnish patients hospitalised due to COVID-19 during the first wave of the pandemic were recruited to a survey of symptoms, quality of life (RAND-36), work status, and health care use one year after hospital discharge. Patients with lung function test and chest x-ray results available from 3-6 months after hospital discharge underwent spirometry and a chest x-ray at one year.

RESULTS

Ninety-six patients responded to the one-year survey, 32 underwent spirometry and 32 a chest x-ray. Of those working full-time before COVID-19, median duration of sick leave was 40 days and 10% had not returned to work at one year. Health-care service use related to COVID-19 after discharge was reported by 79%, 50% using primary care, 34% occupational health care and 32% specialist care, respectively. Tiredness, fatigue, and physical difficulties increased in follow-up (p = 0.022-0.033). Quality of life did not change. Chest x-ray abnormalities decreased in follow-up, with an abnormal chest x-ray in 58% at 3-6 months and 25% at one year. A restrictive spirometry pattern was more common at one year (16 vs. 34%, p = 0.014).

CONCLUSIONS

Prolonged symptoms are common, some patients have decreased lung function, and a small minority of patients still have not returned to work one year after severe COVID-19. This calls for further research into the underlying causes and risk factors for prolonged recovery.

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 .

Pulmonary function in a cohort of heart-healthy individuals from Northern Sweden-a comparison with discordant reference values

BACKGROUND

Dynamic spirometry is an important investigation to differentiate between impaired and normal lung function. This study aimed to evaluate the results of lung function testing in a cohort of subjects from Northern Sweden without any known heart or pulmonary disease. Our focus was to compare with two reference materials that have showed differences in the age-dependency of lung function in Swedish subjects.

METHODS

The study population consisted of 285 healthy adults (148 males, 52%) between 20-90 years of age. The subjects had been randomly selected from the population register for inclusion in a study investigating cardiac function in heart-healthy subjects, but were also assessed with dynamic spirometry. At least seven percent reported smoking. Sixteen subjects presented with pulmonary functional impairments and were excluded from the current study. The sex-specific age-dependency in lung volumes was estimated using the LMS model, where non-linear equations were derived for the mean value (M), the location (L) or skewness, and the scatter (S) or coefficient of variation. This model of the observed lung function data was compared with reference values given by the original LMS model published by the Global Lung Initiative (GLI), and with the model from the recent Obstructive Lung Disease In Norrbotten (OLIN) study, where higher reference values were presented for Swedish subjects than those given by the GLI model.

RESULTS

No differences were found in the age-dependency of pulmonary function between the LMS model developed in the study and the OLIN model. Although the study group included smokers, the original GLI reference values suggested significantly lower normal values of FEV₁ (forced expiratory volume) and FVC (forced vital capacity), and consequently fewer subjects below the lower limit of normality, than both the rederived LMS and OLIN models.

CONCLUSIONS

Our results are in line with previous reports and support that the original GLI reference values underestimate pulmonary function in the adult Swedish population. This underestimation could be reduced by updating the coefficients in the underlying LMS model based on a larger cohort of Swedish citizens than was available in this study.

An Increase in Plasma Adipsin Levels Is Associated With Higher Cumulative Dust Exposure and Airway Obstruction in Foundry Workers

OBJECTIVE

The aim of the study was to assess whether plasma adipokine levels (adipsin, adiponectin, leptin, and resistin) are associated with pulmonary function in foundry workers.

METHODS

We examined 65 dust-exposed foundry workers and 40 nonexposed controls and analyzed their lung function and plasma adipokine levels at baseline and after approximately 7 years of follow-up.

RESULTS

A higher increase in plasma adipsin was associated with the development of airway obstruction in exposed subjects during follow-up after adjusting for body mass index changes during the follow-up period. Furthermore, the increase in adipsin levels was positively associated with cumulative dust exposure even after adjusting for smoking and body mass index changes during follow-up ( P = 0.015).

CONCLUSION

The results suggest that plasma adipsin is involved in the pathogenesis of subclinical airway inflammation and the development of chronic obstruction and is induced by occupational dust exposure.

Normal spirometry prediction equations for the Iranian population

BACKGROUND

This study aimed to establish normative spirometric equations in a healthy population of Iranian children and adults, and compare these equations with those developed by the Caucasian Global Lung Initiative (GLI) for the first time.

METHODS

Spirometric data from healthy Iranian aged 4-82 years sampled in 2019 were used to derive reference equations using the generalized additive model for location (mu), shape (lambda), and scale (sigma).

RESULTS

A total of 418 females and 204 males were included in the study. Applying the GLI standards for the Iranian population resulted from the Z scores of FEV₁, FVC, FEV₁/FVC, and FEF_25-75% was not different from zero. Based on the newly calculated LLN, eleven individuals showed significant values below the LLN for FEV₁/FVC. In all age groups, this frequency was less than 5%, except for men over 70 years of age, which was 12.5%. There are significant differences between new data and GLI for Caucasian data.

CONCLUSION

It is recommended that the values and equations generated from this study should be used by physicians and technicians in their routine practice for the diagnosis and assessment of pulmonary disorders.

Validation of the Global Lung Function Initiative 2012 Spirometry Reference Values in a Healthy Italian Working Population

BACKGROUND

Several studies showed important differences in the interpretation of spirometry based on different reference values, in particular by comparing European Respiratory Society (ERS) 1993 and Global Lung Function Initiative (GLI) 2012. The validation of new reference values in local populations is essential before they can be used in an appropriate manner. This study aimed to investigate the fit of GLI reference values in a healthy Italian working population.

METHODS

Spirometry data were collected in 1355 workers during their health surveillance medical examination conducted for exposure to chemical and biological risk factors. A single portable spirometer that met the ATS/ERS recommendations for occupational testing was used and calibrated daily.

RESULTS

Average z-score were -0.13 (with a median of -0.17), -0.25 (with a median of -0.24), and 0.18 (with a median of 0.17) for FEV₁, FVC, and FEV₁/FVC ratio, respectively. Considering only the normal-weighted workers, the average z-scores were -0.07 (with a median of -0.16), -0.15 (with a median of -0.16), and 0.07 (with a median of 0.02) for FEV₁, FVC, and FEV₁/FVC ratio, respectively.

CONCLUSIONS

GLI 2012 reference values fit the Italian data satisfactorily, resulting as more accurate than ERS 1993, especially in women, normal-weighted subjects, aged 30-50 years, and for height < 165 cm.

Transferring from moisture damaged school building to clean facilities - The avoidance of mold exposure induces a decline in symptoms and improvement in lung function among personnel

Working in a moisture-damaged building can cause different symptoms and effects on lung functions. Moving to a clean environment, it is believed to reduce symptoms and alleviate potential adverse health effects. This case study monitors the health effects of personnel in one school building before and after all school activities were transferred from a moisture-damaged school building to clean premises. The whole school staff was invited to attend this follow-up study. All participants (N = 45) were interviewed, and pulmonary functions were measured by spirometry and exhaled nitric oxide testing (FE_NO) before transferring the school activities to a new building and the control measurements were performed twice; three months and six months after the transfer. After transferring to temporary facilities, 82% of participants felt that their symptoms were improved or resolved and the pulmonary functions were improved; 50% of those who had decreased pulmonary functions at the beginning, their pulmonary function values returned to normal after three months. Over the next six months, the perceived symptoms continued to reduce so that 93% of the respondents felt fully asymptomatic with respect to indoor air, and the spirometry results improved further. Transferring workers from the damaged building to healthy environment provided beneficial health effects on pulmonary functions and to perceived symptoms even in a relatively short time period. Based on this study, and from the perspective of promoting and protecting the health and well-being of personnel, transferring school activities from a moisture damaged building to clean facilities brought considerable advantages, despite the possible cost and difficulties of finding replacement facilities.

Evaluation of the Global Lung Function Initiative 2012 reference values for spirometry in an Iranian population

Spirometry is an important measurement in detecting and monitoring of chronic obstructive pulmonary disease. The validity of the multi-ethnic Global Lung Function Initiative 2012 (GLI-2012) spirometric norms have been debated in some countries. The aim of the present study was to evaluate the applicability of the GLI reference norms in the Iranian population. A cross-sectional study was performed on 622 healthy non-smoker population (204 males and 418 females, age range: 4 ± 82 years) between July 16 and August 27, 2019 in Iran. Z-scores for spirometric data [FEV₁ (forced expiratory volume in 1 s), FVC (forced vital capacity) FEV₁/FVC, and FEF_25-75% (forced expiratory flow averaged over the middle portion of FVC)] were calculated. According to the agreement approved, a mean Z-score outside the range of ± 0.5 was considered clinically significant. The mean (SD) Z-score values of FEV₁, FVC, FEV₁/FVC and FEF_25-75% were 0.44 (1.21), 0.49 (1.14), 0.11 (1.03), and - 1.13 (0.99) in males and 0.61 (1.14), 0.89 (1.26), 0.17 (0.88) and - 0.49 (0.96) in females, respectively. The Z-score of FEV₁/FVC was below the lower limit of normal (LLN) in 3.43% of men and 2.01% of women (in ≥ 21 years), while these values were significantly higher in people under 21 years old (46.2% in boys and 40.0% in girls). The GLI reference values are not perfect for the Iranian population, especially in children below 10 years old. The use of the GLI reference values was appropriate in population above 21 years; however, they would overestimate the prevalence of airway obstruction in individuals below 21 years.

Lung function and exercise capacity 6 months after hospital discharge for critical COVID-19

BACKGROUND

The significant morbidity caused by COVID-19 necessitates further understanding of long-term recovery. Our aim was to evaluate long-term lung function, exercise capacity, and radiological findings in patients after critical COVID-19.

METHODS

Patients who received treatment in ICU for COVID-19 between March 2020 and January 2021 underwent pulmonary function tests, a 6MWD and CXR 6 months after hospital discharge.

RESULTS

A restrictive ventilatory defect was found in 35% (23/65) and an impaired diffusing capacity in 52% (32/62) at 6 months. The 6-minute walk distance was reduced in 33% (18/55), and 7% (4/55) of the patients had reduced exercise capacity. Chest X-ray was abnormal in 78% (52/67) at 6 months after hospital discharge.

CONCLUSION

A significant number of patients had persisting lung function impairment and radiological abnormalities at 6 months after critical COVID-19. Reduced exercise capacity was rare.

Evaluation of the Global Lung Function Initiative reference equations in Belgian adults

Background

Over the past decade, the Global Lung Function Initiative (GLI) Network has published all-age reference equations on spirometry, diffusing capacity of the lung for carbon monoxide (D_LCO) and lung volumes.

Methods

We evaluated the appropriateness of these equations in an adult Caucasian population. Retrospective lung function data on subjects who performed tests prior to a diagnostic sleep investigation were analysed. From the medical records, lung healthy, lifetime nonsmoking, nonobese subjects were selected, resulting in a population of 1311 subjects (68% male; age range 18–88 years).

Results

Multiple linear regression analysis revealed that lung function z-scores did not differ between subjects with and without sleep apnoea but did depend on height and age. The average forced expiratory volume in 1 s (FEV₁)/forced vital capacity (FVC) z-score was 0 but exhibited an inverse association with height in both sexes (p<0.01). Values of FEV₁ and FVC in both sexes were larger than predicted (mean±sd z-score +0.30±0.96 or 104±13% pred; p<0.01). Overall, static lung volumes and D_LCO were adequately predicted. However, D_LCO z-scores were inversely associated with height in males and age in females (p<0.01). For all lung function indices, the observed scatter was reduced compared with the prediction. Therefore, for all indices <5% of the data were below the GLI-proposed lower limit of normal (LLN) threshold.

Conclusion

GLI reference equations provide an adequate fit in Belgian adults. However, the GLI-proposed LLN is too low for our Antwerp population, resulting in underdiagnosis of disease. Furthermore, airway obstruction and diffusion disorders might be misclassified due to height and age associations.

Overall, GLI reference equations for lung function appropriately describe the data in Belgian adults. However, airway obstruction and diffusion disorders might be misdiagnosed at age and height extremes, and the GLI LLN was too low in this population.https://bit.ly/3jdauLE

Altered Expiratory Flow Dynamics at Peak Exercise in Adult Men With Well-Controlled Type 1 Diabetes

Type 1 diabetes may, in time, cause lung dysfunction including airflow limitation. We hypothesized that ventilatory flow morphology during a cardiopulmonary exercise test (CPET) would be altered in adult men with well-controlled type 1 diabetes. Thirteen men with type 1 diabetes [glycated hemoglobin A1c 59 (9) mmol/mol or 7.5 (0.8)%, duration of diabetes 12 (9) years, and age 33.9 (6.6) years] without diagnosed diabetes-related complications and 13 healthy male controls [age 37.2 (8.6) years] underwent CPET on a cycle ergometer (40 W increments every 3 min until volitional fatigue). We used a principal component analysis based method to quantify ventilatory flow dynamics throughout the CPET protocol. Last minute of each increment, peak exercise, and recovery were examined using linear mixed models, which accounted for relative peak oxygen uptake and minute ventilation. The type 1 diabetes participants had lower expiratory peak flow (P = 0.008) and attenuated slope from expiration onset to expiratory peak flow (P = 0.012) at peak exercise when compared with the healthy controls. Instead, during submaximal exercise and recovery, the type 1 diabetes participants possessed similar ventilatory flow dynamics to that of the healthy controls. In conclusion, men with relatively well-controlled type 1 diabetes and without clinical evidence of diabetes-related complications exhibited attenuated expiratory flow at peak exercise independently of peak oxygen uptake and minute ventilation. This study demonstrates that acute exercise reveals alterations in ventilatory function in men with type 1 diabetes but not until peak exercise.

Lung function during and after acute respiratory infection in COVID-19 positive and negative outpatients

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been associated with prolonged post-acute symptoms in at least 10% of patients [1, 2]. The majority of published data evaluates hospitalised patients with severe SARS-CoV-2 disease (COVID-19) with symptoms and pulmonary function defects several months after discharge [1]. Most of the infected subjects develop mild symptoms and are treated as outpatients. Though they are also reported to suffer from prolonged symptoms, their lung function is studied far less. Furthermore, the prolonged symptoms and objectively measurable findings are usually not compared to a group suffering from airway infection caused by other pathogens [2]. As spirometry and other aerosol-producing procedures are minimised during the pandemic, there are no reports on lung function during acute COVID-19.

At acute phase, outpatients with mild COVID-19 had more symptoms, higher small airway resistance and poorer lung elasticity compared to outpatients with other respiratory infections, but there was no difference between the groups after 2 monthshttps://bit.ly/3nalPye

Small airway function in Finnish COVID-19 survivors

Follow-up studies of COVID-19 patients have found lung function impairment up to six months after initial infection, but small airway function has not previously been studied. Patients (n = 20) hospitalised for a severe SARS-CoV-2 infection underwent spirometry, impulse oscillometry, and multiple measurements of alveolar nitric oxide three to six months after acute infection. None of the patients had small airway obstruction, nor increased nitric oxide concentration in the alveolar level. None of the patients had a reduced FEV₁/FVC or significant bronchodilator responses in IOS or spirometry. In conclusion, we found no evidence of inflammation or dysfunction in the small airways.

Addressing Race in Pulmonary Function Testing by Aligning Intent and Evidence With Practice and Perception

The practice of using race or ethnicity in medicine to explain differences between individuals is being called into question because it may contribute to biased medical care and research that perpetuates health disparities and structural racism. A commonly cited example is the use of race or ethnicity in the interpretation of pulmonary function test (PFT) results, yet the perspectives of practicing pulmonologists and physiologists are missing from this discussion. This discussion has global relevance for increasingly multicultural communities in which the range of values that represent normal lung function is uncertain. We review the underlying sources of differences in lung function, including those that may be captured by race or ethnicity, and demonstrate how the current practice of PFT measurement and interpretation is imperfect in its ability to describe accurately the relationship between function and health outcomes. We summarize the arguments against using race-specific equations as well as address concerns about removing race from the interpretation of PFT results. Further, we outline knowledge gaps and critical questions that need to be answered to change the current approach of including race or ethnicity in PFT results interpretation thoughtfully. Finally, we propose changes in interpretation strategies and future research to reduce health disparities.

Applicability of GLI 2012 spirometry equation among preschool aged Jordanian

OBJECTIVES

The Validation of Global Lung Initiative (GLI 2012) equations is required prior to their application in clinical practice in different regions. This study validated the GLI 2012 equations in Middle Eastern preschool aged children, which was not previously conducted.

STUDY DESIGN

Spirometry measures were collected from 765 (54% males) healthy 3 to 5-year-old Jordanian children. z scores, percent predicted values, and frequency of measures below lower limit than normal (LLN) were calculated using GLI 2012 equations for Caucasians and Other or Mixed.

RESULTS

The mean of z-scores produced by GLI 2012 equation for Caucasians in FEV_0.75, FEV₁, FVC, FEV₁/FVC% and FEF25-75 in boys were 0.03, 0.02, -0.13, 0.26 and -0.08 respectively, while in girls it was -0.03, 0.01, 0.02, -0.01 and -0.04 respectively, and the mean of z-scores produced by GLI-2012 Other or Mixed equations in FEV₁, FVC, FEV₁/FVC% and FEF25-75 in boys were 0.56, 0.51, 0.09 and 0.12 respectively, and in girls it was 0.56, 0.67, -0.22 and 0.18 respectively. The frequency of measures below LLN as produced by Caucasians equation were not significantly different from the expected 5% in any of the spirometry parameters.

CONCLUSION

The GLI 2012 for Caucasians is a reasonable fit for Jordanian preschool aged children.

High alveolar nitric oxide is associated with steeper lung function decline in foundry workers

Occupational dust exposure induces inflammatory responses that often precede the onset of clinical disease. Inflammation in the peripheral part of the lung can be demonstrated by measuring the alveolar NO concentration (C_ANO) in exhaled breath. The aim of the study was to assess whether cumulative dust exposure affects the change in C_ANO during follow-up and whether baseline C_ANO can predict an impairment in lung function during follow-up in foundry workers. We examined 74 dust-exposed and 42 nonexposed foundry workers and measured C_ANO and lung function at baseline and after 7 years of follow-up. An increase in C_ANO during the follow-up period was positively associated with cumulative dust exposure in foundry work (p= 0.035). Furthermore, a higher baseline C_ANO was associated with an accelerated decline in the forced vital capacity (FVC) during the follow-up period (absolute decrease in FVCp= 0.021, relative decrease in FVCp= 0.017). Higher cumulative dust exposure in foundry work is associated with a greater increase in C_ANO during follow-up, suggesting ongoing pulmonary inflammation in these subjects. Importantly, a high baseline C_ANO is associated with an accelerated decline in lung function, suggesting that C_ANO measurements might serve as a screening tool for high-risk workers.

The applicability of the global lung initiative equations and other regional equations on a sample of healthy Middle Eastern adolescents

BACKGROUND

The Global Lung Initiative 2012 (GLI-2012) spirometry equations are multi-ethnic equations that cover all ages between 3 and 95. However, there is a need to evaluate the suitability of these equations to a sample of Middle Eastern adolescents prior to being applied in clinical practice. The aim of this study is to evaluate the suitability of GLI-2012 equations and two regional equations to a sample of Jordanian adolescents.

METHODS

Spirometric measures were collected from 1036 healthy 14 to 17-year-old Jordanian children. z-scores, predicted values, percent predicted values, and frequency of measures below lower limit of normal (LLN) were calculated for each adolescent using the studied equations.

RESULTS

The means of z-scores produced by GLI-2012 equations for Caucasians in forced expiratory volume in the first second (FEV1), forced vital capacity (FVC), FEV1/FVC% and mid forced expiratory flow (FEF25-75) for boys were 0.12, -0.06, 0.34 and 0.09, respectively, while for girls they were -0.09, -0.16, 0.19 and -0.05, respectively. The mean of z-scores produced by GLI-2012 Other or Mixed equations in FEV1, FVC, FEV1/FVC% and FEF25-75 for boys were 0.74, 072, 021 and 0.33, respectively, and for girls were 0.53, 0.56,0.02 and 0.2, respectively. The frequency of measures below LLN as produced by GLI 2012 for Caucasians were significantly different from the expected 5% in FEV1 and FEF25-75 in boys only, whereas Other or Mixed produced frequencies significantly different from the expected 5% in most of the parameters.

CONCLUSION

Spirometry reference equations formulated for Jordanian adolescents may improve the diagnosis and treatment of asthma in Jordan.

Peak In- and Expiratory Flow Revisited: Reliability and Reference Values in Adults

BACKGROUND

While peak in- and expiratory flow rates offer valuable information for diagnosis and monitoring in respiratory disease, these indices are usually considered too variable to be routinely used for quantification in clinical practice.

OBJECTIVES

The aim of the study was to obtain reproducible measurements of maximal inspiratory flow rates and to construct reference equations for peak in- and expiratory flows (PIF and PEF).

METHOD

With coaching for maximal effort, 187 healthy Caucasian subjects (20-80 years) performed at least 3 combined forced inspiratory and expiratory manoeuvres, until at least 2 peak inspiratory flow measurements were within 10% of each other. The effect on PIF preceded by a slow expiration instead of a forced expiration and PIF repeatability over 3 different days was also investigated in subgroups. Reference values and limits of normal for PIF, mid-inspiratory flow, and PEF were obtained according to the Lambda-Mu-Sigma statistical method.

RESULTS

A valid PIF could be obtained within 3.3 ± 0.6(SD) attempts, resulting in an overall within-test PIF variability of 4.6 ± 3.2(SD)%. A slow instead of a forced expiration prior to forced inspiration resulted in a significant (p < 0.001) but small PIF increase (2.5% on average). Intraclass correlation coefficient for between-day PIF was 0.981 (95% CI: 0.960-0.992). Over the entire age range, inter-subject PIF variability was smaller than in previous reports, and PIF could be predicted based on its determinants gender, age, and height (r2 = 0.53).

CONCLUSIONS

When adhering to similar criteria for the measurement of effort-dependent portions of inspiratory and expiratory flow-volume curves, performed according to current ATS/ERS standards, it is possible to obtain reproducible PIF and PEF values for use in routine clinical practice.

Lung function parameters among Australian Aboriginal 'apparently healthy' adults: an Australian Caucasian and Global Lung Function Initiative (GLI-2012) various ethnic norms comparative study

Background: There is sparse literature evidence evaluating the applicability of the GLI-2012 spirometric norms for Australian Aboriginal adults.Methods: Lung function parameters (LFPs) were compared between Australian Aboriginal and Australian Caucasians, and the fit of Australian Aboriginals LFPs with various ethnic GLI equations was tested.Results: Of 1350 and 5634 Pulmonary function tests (PFTs) in Australian Aboriginal and Australian Caucasian adults, 153 and 208 PFTs matched for anthropometrics and normal chest radiology, respectively. Absolute FVC and FEV₁ values were 20% lower in Australian Aboriginals compared to Australian Caucasians. Differences remained significant after accounting for age, sex, height, weight and smoking status in multivariate regression (FVC -0.84 L (-0.98, -0.71), FEV₁ - 0.72 L (-0.84, -0.59), but with nearly preserved FEV₁/FVC. GLI-2012 transformation resulted in z-scores significantly below zero for each of FVC, FEV₁ and FEV₁/FVC with z-scores ranging from -4.52 (-4.87, -4.16) for North East Asian FVC transformation for males, to -0.34 (-0.73, 0.05) for Black FVC transformation for females.Conclusions: Australian Aboriginal adults had 20% lower values for FVC and FEV₁ but nearly preserved absolute FEV₁/FVC in comparison to Australian Caucasians. The GLI-2012 spirometric norms do not appear to fit for Australian Aboriginal adults regardless of which ethnicity options selected, including 'others/mixed'.

Reference values for spirometry in Brazilian children

Objective:

To generate reference values for spirometry in Brazilian children 3-12 years of age and to compare those values with the values employed in the equations currently in use in Brazil.

Methods:

This study involved healthy children, 3-12 years of age, recruited from 14 centers (primary data) and spirometry results from children with the same characteristics in six databases (secondary data). Reference equations by quantile regressions were generated after log transformation of the spirometric and anthropometric data. Skin color was classified as self-reported by the participants. To determine the suitability of the results obtained, they were compared with those predicted by the equations currently in use in Brazil.

Results:

We included 1,990 individuals from a total of 21 primary and secondary data sources. Of those, 1,059 (53%) were female. Equations for FEV₁, FVC, the FEV₁/FVC ratio, FEF between 25% and 75% of the FVC (FEF_25-75%) and the FEF_25-75%/FVC ratio were generated for white-, black-, and brown-skinned children. The logarithms for height and age, together with skin color, were the best predictors of FEV₁ and FVC. The reference values obtained were significantly higher than those employed in the equations currently in use in Brazil, for predicted values, as well as for the lower limit of normality, particularly in children with self-reported black or brown skin.

Conclusions:

New spirometric equations were generated for Brazilian children 3-12 years of age, in the three skin-color categories defined. The equations currently in use in Brazil seem to underestimate the lung function of Brazilian children 3-12 years of age and should be replaced by the equations proposed in this study.

Spirometry: A Need for Periodic Updates of National Reference Values

The aim of the study was to assess the need for changes in spirometry reference values in the Polish population with time lapse, as the aftereffect of a radical socioeconomic overturn of the 1990. We retrospectively analyzed data files on forced expiratory volume in 1 s (FEV1), vital capacity (VC), and forced VC (FVC) in healthy, never-smoking Caucasians (731 females and 327 males) obtained in in 1993-1998. We assessed a discrepancy between the then measured values of these variables, on the one side, and the corresponding European Community for Steel and Coal (ECSC) predicted values or the current updated predicted values for the Polish population, on the other side. We found that those old measured values approximately corresponded to the ECSC reference, but they were appreciably lower than the current Polish reference values; the younger the subjects the greater the difference. The current Polish reference values of FVC were much closer to the old measured VC than to the old measured FVC values, which introduces a substantial discrepancy between the past and present FVCs. We conclude that the spirometry reference values may change with time lapse. Thus, accuracy of prediction equations should be periodically updated, which seems to particularly concern the equations elaborated for the nations that undergo rapid economic developments connected with changes in living standards.

Reference equations for spirometry in healthy Asian children aged 5 to 18 years in Taiwan

Background and objective

This study aimed to establish reference equations for spirometry in healthy Taiwanese children and assess the applicability of the Global Lung Function Initiative (GLI)-2012 equations to Taiwanese children.

Methods

Spirometric data collected from 757 healthy Taiwanese children aged 5 to 18 years in a population-based cohort study. Prediction equations derived using linear regression and the generalized additive models for location, scale and shape (GAMLSS) method, respectively.

Results

The GLI-2012 South East Asian equations did not provide a close fit with mean ± standard error z-scores of −0.679 ± 0.030 (FVC), −0.186 ± 0.044 (FEV₁), −0.875 ± 0.049 (FEV₁/FVC ratio) and −2.189 ± 0.063 (FEF_25-75) for girls; and 0.238 ± 0.059, −0.061 ± 0.053, −0.513 ± 0.059 and −1.896 ± 0.077 for boys. The proposed GAMLSS models took age, height, and weight into account. GAMLSS models for boys and girls captured the characteristics of spirometric data in the study population closely in contrast to the linear regression models and the GLI-2012 equations.

Conclusion

This study provides up-to-date reference values for spirometry using GAMLSS modeling in healthy Taiwanese children aged 5 to 18 years. Our study provides evidence that the GLI-2012 reference equations are not properly matched to spirometric data in a contemporary Taiwanese child population, indicating the urgent need for an update of GLI reference values by inclusion of more data of non-Caucasian decent.

[Spirometric reference values in the Bantu population aged 20-70 years in Kinshasa]

INTRODUCTION

Spirometric reference values cannot be extrapolated in the populations, being subject to many environmental and human variables; hence the interest of local studies in this field.

METHODS

This study aims to determine the reference values among healthy adults in Kinshasa. We conducted a cross-sectional study including 7443 subjects (3208 women, 43%). FEV1, FVC, PEF were correlated with anthropometric data. Five age groups were formed and comparisons were made on the basis of sex, age, BMI and of the practice of sporting activity.

RESULTS

Differences are evident between the sexes, in terms of FEV1 (3.00 vs 2.21 L), FVC (3.19 vs 2.38) and the PEF (6.8 vs 5.70 L/s); same as for the outer age categories. FEV1 ranged between 2.33 et 4.54 vs 1.93-3.3 L in the age group 20-29 years and 1,76-3,39 vs 1,60 vs 2,53 L in the age group 60-70 years; FVC ranged between 2,44-4,89 vs 1,96-3,56 L and 1,79-3,78 vs 1,66-2,74 L ; PEF ranged between 4,34-12.2 vs 3,62-8.58 L/s and 2.99-6.76 vs 2.99-7.34L/s in the age group 60-70 years.

CONCLUSION

The differences related to gender, age, anthropometric data as well as to the practice of sporting activity are obvious. These results warrant further and more extended investigations and show the relevance of values based on percentiles in the determinantion of a spirometry standard in a given population.

Global Lung Function Initiative-2012 'other/mixed' spirometry reference equation provides the best overall fit for Australian Aboriginal and/or Torres Strait Islander children and young adults

BACKGROUND AND OBJECTIVE

Ethnic-specific reference equations are recommended when performing spirometry. In the absence of appropriate reference equations for Australian Aboriginal and/or Torres Strait Islanders (Indigenous), we determined whether any of the existing Global Lung Function Initiative (GLI)-2012 equations were suitable for use in Indigenous children/young adults.

METHODS

We performed spirometry on 1278 participants (3-25 years) who were identified as Aboriginal, Torres Strait Islander or 'both'. Questionnaires and medical records were used to identify 'healthy' participants. GLI2012_DataConversion software was used to apply the 'Caucasian', 'African-American' and 'other/mixed' equations.

RESULTS

We included 930 healthy participants. Mean z-scores for forced expiratory volume in 1 s (FEV₁ ) and forced vital capacity (FVC) were lower than the Caucasian predicted values (range: -0.53 to -0.60) and higher than African-American (range: 0.70 to 0.78) but similar to other/mixed (range: 0.00 to 0.08). The distribution of healthy participants around the upper and lower limits of normal (~5%) fit well for the other/mixed equation compared to the Caucasian and African-American equations.

CONCLUSION

Of the available GLI-2012 reference equations, the other/mixed reference equation provides the best overall fit for Indigenous Australian children and young adults (3-25 years). Healthy data from additional communities and adults around Australia will be required to confirm generalizability of findings.

Demographics and survival of patients with idiopathic pulmonary fibrosis in the FinnishIPF registry

Idiopathic pulmonary fibrosis (IPF) is characterised by unpredictable disease course and poor survival. After the introduction of novel antifibrotic drugs, the prognosis of patients with IPF is probably changing. FinnishIPF, a nationwide registry of carefully characterised patients, was initiated in Finland in 2011. For the data analysis, we included 453 incident IPF patients diagnosed during 2011-2015. In this study, we describe the demographics and prognosis of these real-life patients. The median overall survival time of registered IPF patients was 4.5 years. The transplant-free survival at 1, 2, 3, 4 and 5 years was 95%, 83%, 70%, 58% and 45%, respectively. Smoking did not have any effect on survival. 117 (26%) patients received pirfenidone or nintedanib. Patients who received ≥6 months of treatment had better survival compared with those who did not receive treatment but this difference disappeared after age adjustment. The transplantation rate was 3%. Although IPF is diagnosed in Finland at a older age, the prognosis is better than expected due to a relatively well preserved lung function at diagnosis. Age and pulmonary function were identified as independent predictors of survival in the entire IPF patient population as well as in patients who had received antifibrotic treatment.

Advances in spirometry testing for lung function analysis

Introduction: Spirometry, the most common lung function test, is used to evaluate individuals with respiratory complaints or known respiratory disease. However, its underutilization and the misinterpretation of its parameters are causes for concern. Areas covered: This review describes new spirometry-derived metrics, new reference equations, recent recommendations for presentation of results, recent spirometry-based prevalence studies, and technological advances in spirometry equipment. Expert opinion: The underutilization of spirometry can be overcome by increasing access to portable, hand-held, and user-friendly spirometers, together with strategies that increase awareness of the importance of spirometry. New metrics derived from spirometry, together with traditional spirometric criteria, can identify individuals with structural lung disease and respiratory morbidity. Some problems with the reference equations were solved by the Global Lung Function Initiative (GLI), which covers a wider age range and more ethnic groups and provides limits of normality using the z-score. Despite these advantages, the GLI equations lack data from large populations (especially those from Africa, South Asia, and Latin America) and greater representation of older people. Another disadvantage attributed to the GLI is the lack of predicted values for peak expiratory flow and other airflows, limiting the interpretation of the maximal expiratory flow-volume curve.

The multi-ethnic global lung initiative 2012 (GLI-2012) norms reflect contemporary adult's Algerian spirometry

Background

The validation of the multi-ethnic GLI-2012 spirometric norms has been debated in several countries. However, its applicability in Algeria has not been verified.

Aim

To ascertain how well the GLI-2012 norms fit contemporary adult Algerian spirometric data.

Methods

This was a cross-sectional study of a convenience sample of 300 healthy non-smoker adults (50% men, age range: 18–85 years) recruited from the Algiers region general population. All participants underwent a clinical examination and a plethysmography measurement. Z-scores for some spirometric data [FEV₁, FVC, FEV₁/FVC and forced expiratory flow at 25–75% of FVC (FEF_25-75%)] were calculated. If the average Z-score deviated by “< ± 0.5” from the overall mean, the GLI-2012 norms would be considered as reflective of contemporary Algerian spirometry.

Results

The means±SDs of age, height, weight, FVC, FEV₁, FEV₁/FVC and FEF_25-75% of the participants were, respectively, 48±17 years, 1.65±0.10 m, 73±14 kg, 4.04±1.04 L, 3.18±0.82 L, 0.79±0.05 and 4.09±1.09 L/s. Almost the quarter of participants were obese. The total sample means±SDs Z-scores were 0.22±0.87 for FVC, 0.04±0.88 for FEV₁, -0.34±0.67 for FEV₁/FVC and 0.93±0.79 for FEF_25-75%. For men and women, only the means±SDs of the FEF_25-75% Z-scores exceeded the threshold of “± 0.5”, respectively, 1.13±0.77 and 0.73±0.76.

Conclusion

Results of the present study, performed in an Algerian population of healthy non-smoking adults, supported the applicability of the GLI-2012 norms to interpret FEV₁, FVC and FEV₁/FVC but not the FEF_25-75%.

Reference values of inspiratory spirometry for Finnish adults

Inspiratory spirometry is used in evaluation of upper airway disorders e.g. fixed or variable obstruction. There are, however, very few published data on normal values for inspiratory spirometry. The main aim of this study was to produce reference values for inspiratory spirometry for healthy Finnish adults. Inspiratory spirometry was preplanned to a sample of the Finnish spirometry reference values sample. Data was successfully retrieved from 368 healthy nonsmoking adults (132 males) between 19 and 83 years of age. Reference equations were produced for forced inspiratory vital capacity (FIVC), forced inspiratory volume in one second (FIV1), FIV1/FIVC, peak inspiratory flow (PIF) and the ratios of FIV1/forced expiratory volume in one second and PIF/peak expiratory flow. The present values were compared to PIF values from previously used Finnish study of Viljanen et al. (1982) reference values and Norwegian values for FIV1, FIVC and FIV1/FIVC presented by Gulsvik et al. (2001). The predicted values from the Gulsvik et al. (2001), provided a good fit for FIVC, but smaller values for FIV1 with mean 108.3 and 109.1% of predicted values for males and females, respectively. PIF values were 87.4 and 91.2% of Viljanen et al. (1982) predicted values in males and females, respectively. Differences in measurement methods and selection of results may contribute to the observed differences. Inspiratory spirometry is technically more demanding and needs repeatability criteria to improve validity. New reference values are suggested to clinical use in Finland when assessing inspiratory spirometry. Utility of inspiratory to expiratory values indices in assessment of airway collapse need further study.

Reference values for spirometry in elderly individuals: a cross-sectional study of different reference equations

Background

Spirometry is the single most important test for the evaluation of respiratory function. The results are interpreted by comparing measured data with predicted values previously obtained from a reference population. Reference equations for spirometry have been discussed previously. The aim of this study was to compare reference values based on National Health and Nutrition Assessment Survey (NHANES III), European Community of Steel and Coal (ECSC), and Global Lung Initiative (GLI) equations in an elderly sample population.

Methods

Subjects from the Geriatric Study on Health Effects of Air Quality in elder care centres who met the inclusion criteria were enrolled. Spirometry was performed according to international guidelines. The forced vital capacity, forced expiratory volume in 1 s, and FEV₁/FVC ratio were reported as percentages of the predicted value, and the lower limit of normality was calculated.

Results

Out of 260 elderly patients, 69.6% were women; the mean age was 83.0 ± 6.46 years with an age range of 65–95 years. The lowest %FVC and %FEV₁ values were obtained using the GLI reference equations. However, when NHANES III equations were used, the FEV₁/FVC ratio was higher than ratios obtained from GLI and ECSC equations. The prevalence of airway obstruction was highest using ECSC equations, while GLI equations demonstrated more restrictive defects.

Conclusions

The present study showed meaningful differences in the reference values, and consequently, in the results obtained using NHANES III, ECSC, and GLI reference equations. The spirometry interpretation was also influenced by the reference equations used.

The multi-ethnic global lung initiative 2012 and Third National Health and Nutrition Examination Survey reference values do not reflect spirometric measurements in Black boys and men from Tanzania

The interpretation of spirometric results of Black Africans according to reference standards based on data from outside their native environment may lead to the wrong conclusions. This article aims to characterize the ventilatory capacity of boys and men from Tanzania according to forced expiratory volume in one second (FEV1 ), forced vital capacity (FVC), peak expiratory flow (PEF) and FEV1 /FVC based on the collected anthropological material and to compare them to NHANES III, Third National Health and Nutrition Examination Survey (NHANES III) African American predicted values and GLI2012 equations. The analysis included spirometric measurements of n = 295 participants from Tanzania. Pearson's correlation analysis and the backward stepwise multiple regression analysis were performed. FEV1 , FVC, PEF and FEV1 /FVC results were compared to the NHANES III African American predicted values as well as to the GLI2012 equations. FEV1 measurements are lower than the reference values according to NHANES III and GLI2012 equations by 22·1% and 25·8%. FVC results fell short of the NHANES III predicted by 29·5% and of GLI2012 by 32·5%. The average %FEV1 /FVC scores for the boys and men exceeded the recommended GLI2012 predicted by 10·5-15·2%. All the spirometric measurements included in the analysis were statistically significantly correlated with age, body height, sitting height, trunk length and body weight. The application of prediction formulae developed for non-African populations overestimates the values for Black Africans. The results of spirometric measurements are ecosensitive and dependent on various external (environmental) factors.

Spirometry reference values for population aged 7-80 years in China

BACKGROUND AND OBJECTIVE

Lung function tests are widely used in clinical and public health practice; however, no valid spirometry reference values were available for the general population in China. This study aimed to provide valid spirometry predictive equations for the general population in China, and to evaluate the predictive performance of previously used equations.

METHODS

Data from the China National Health Survey 2012-2015 and the 'Generalized Additive Models for Location, Scale and Shape' statistical modelling method were used to establish spirometry predictive equations for forced expiratory volume in 1 s (FEV₁ ), forced vital capacity (FVC) and FEV₁ /FVC. Paired t-tests were used to examine differences between spirometry measurements in this sample and predicted values of four previous spirometry predictive equations.

RESULTS

This study included 3130 lifetime non-smokers (713 males and 2417 females) aged 7-80 years in China. Spirometry predictive equations with age and height as predictive variables plus age-specific splines were established separately by gender. Most previous spirometry predictive equations were found to significantly overestimate (maximum of 3.69% in FEV₁ , 1.87% in FVC and 4.19% in FEV₁ /FVC for males; 11.46% in FEV₁ , 7.28% in FVC and 3.78% in FEV₁ /FVC for females) or underestimate (maximum of 5.75% in FEV₁ and 8.12% in FVC for males; 7.89% in FEV₁ and 9.32% in FVC for females) lung function measurements when applied to this sample population.

CONCLUSION

This study addressed the urgent need for valid and up-to-date spirometry reference values for the general population in China. Moreover, previous spirometry predictive equations showed unfavourable generalizability to this sample population.

The Global Lung Function Initiative 2012 Equations Are as Well-Suited as Local Population Derived Equations to a Sample of Healthy Professional Firefighters

BACKGROUND AND OBJECTIVE

We aimed to assess the validity of using the Global Lung Function Initiative's (GLI) 2012 equations to interpret lung function data in a healthy workforce of South Australian Metropolitan Fire Service (SAMFS) personnel.

METHODS

Spirometry data from 212 healthy, nonsmoking SAMFS firefighters were collected and predicted normal values were calculated using both the GLI and local population derived (Gore) equations for forced expiratory volume in one second (FEV1), forced vital capacity (FVC), and FEV1/FVC. Two-tailed paired sample Student's t-tests, Bland-Altman assessments of agreement, and z-scores were used to compare the two prediction methods.

RESULTS

The equations showed good agreement for mean predicted FEV1, FVC, and FEV1/FVC. Mean z-scores were similar for FEV1 and FVC, although not FEV1/FVC, but greater than 0.5. Differences between the calculated lower limits of normal (LLN) were significant (p < 0.01), clinically meaningful, and resulted in an 8% difference in classification of abnormality using the FEV1/FVC ratio.

CONCLUSIONS

The GLI equations predicted similar lung function as population-specific equations and resulted in a lower incidence of obstruction in this sample of healthy SAMFS firefighters. Further, interpretation of spirometry data as abnormal should be based on both an FEV1 and FEV1/FVC ratio < LLN.

Reference values for pulmonary diffusing capacity for adult native Finns

Measurement standards for pulmonary diffusing capacity were updated in 2005 by the ATS/ERS Task Force. However, in Finland reference values published in 1982 by Viljanen et al. have been used to date. The main aim of this study was to produce updated reference models for single-breath diffusing capacity for carbon monoxide for Finnish adults. Single-breath diffusing capacity for carbon monoxide was measured in 631 healthy non-smoking volunteers (41.5% male). Reference values for diffusing capacity (DLCO), alveolar volume (VA), diffusing capacity per unit of lung volume (DLCO/VA), and lung volumes were calculated using a linear regression model. Previously used Finnish reference values were found to produce too low predicted values, with mean predicted DLCO 111.0 and 104.4%, and DLCO/VA of 103.5 and 102.7% in males and females, respectively. With the European Coalition for Steel and Coal (ECSC) reference values there was a significant sex difference in DLCO/VA with mean predicted 105.4% in males and 92.8% in females (p < .001). New reference values for DLCO, DLCO/VA, VA, vital capacity (VC), inspiratory vital capacity (IVC), and inspiratory capacity (IC) are suggested for clinical use to replace technically outdated reference values for clinical applications.

Global Lung Function Initiative 2012 reference equations for spirometry in the Norwegian population

We studied the fit of the Global Lung Function Initiative (GLI) all-age reference values to Norwegians, compared them with currently used references (European Community for Steel and Coal (ECSC) and Zapletal) and estimated the prevalence of obstructive lung disease.

Spirometry data collected in 30 239 subjects (51.7% females) aged 12–90 years in three population-based studies were converted to z-scores.

We studied healthy non-smokers comprising 2438 adults (57.4% females) aged 20–90 years and 8725 (47.7% female) adolescents aged 12–19 years. The GLI-2012 prediction equations fitted the Norwegian data satisfactorily. Median±sd z-scores were respectively 0.02±1.03, 0.01±1.04 and −0.04±0.91 for forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC in males, and −0.01±1.02, 0.07±0.97 and −0.21±0.82 in females. The ECSC and Zapletal references significantly underestimated FEV1 and FVC. Stricter criteria of obstruction (FEV1/FVC <GLI-2012 lower limit of normal (LLN)) carried a substantially higher risk of obstructive characteristics than FEV1/FVC <0.7 and >GLI-2012 LLN. Corresponding comparison regarding myocardial infarction showed a four-fold higher risk for women.

The GLI-2012 reference values fit the Norwegian data satisfactorily and are recommended for use in Norway. Correspondingly, the FEV1/FVC GLI-2012 LLN identifies higher risk of obstructive characteristics than FEV1/FVC <0.7.

GOLD criteria overestimate airflow limitation in one-third of cases in the general Finnish population

The Global Initiative for Chronic Obstructive Lung Disease (GOLD) diagnostic criteria for chronic obstructive pulmonary disease (COPD) use a fixed threshold of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) ratio (<0.70) in post-bronchodilation spirometry to indicate disease, which has been shown to underestimate and overestimate disease prevalence in younger and older adults, respectively, whilst criteria based on reference values have better accuracy. Differences in reference values have limited their use in international studies. However, the new Global Lung Function Initiative reference values (GLI2012) showed FEV1/FVC to be the least dependent on ethnicity. The aim of this study was to assess the prevalence of airflow limitation with GLI2012 and the degree of underdetection or overestimation related to the use of GOLD in the general population. A Finnish population sample of 1323 subjects (45% male) with post-bronchodilation spirometry was studied. 80 subjects (6.0%) and 55 subjects (4.2%) were identified with airflow limitation with GOLD and GLI2012 criteria, respectively. The proportion of overestimation with GOLD increased with age from 25% of cases in 50-year-olds to 54% in 70-year-olds. Using z-score-based grading resulted in more dispersion in severity grading. In conclusion, the GOLD criteria cause a marked overestimation already from 50-year-olds and should be replaced with the GLI2012 criteria to improve diagnostic accuracy.

Prevalence of abnormal findings when adopting new national and international Global Lung Function Initiative reference values for spirometry in the Finnish general population

BACKGROUND

New Finnish (Kainu2015) and international Global Lung Function Initiative (GLI2012) reference values for spirometry were recently published. The aim of this study is to compare the interpretative consequences of adopting these new reference values with older, currently used Finnish reference values (Viljanen1982) in the general population of native Finns.

METHODS

Two Finnish general population samples including 1,328 adults (45% males) aged 21-74 years were evaluated. Airway obstruction was defined as a reduced ratio of forced expiratory volume in one second (FEV1)/forced vital capacity (FVC), possible restrictive pattern as reduced FVC, and decreased ventilatory capacity as reduced FEV1 below their respective 2.5th percentiles. The severity gradings of reduced lung function were also compared.

RESULTS

Using the Kainu2015 reference values, the prevalence of airway obstruction in the population was 5.6%; using GLI2012 it was 4.0% and with Viljanen1982 it was 13.0%. Possible restrictive pattern was found in 4.2% using the Kainu2015 values, in 2.0% with GLI2012, and 7.9% with the Viljanen1982 values. The prevalence of decreased ventilatory capacity was 6.8, 4.0, and 13.3% with the Kainu2015, GLI2012 and Viljanen1982 values, respectively.

CONCLUSIONS

The application of the GLI2012 reference values underestimates the prevalence of abnormal spirometric findings in native Finns. The adoption of the Kainu2015 reference values reduces the prevalences of airways obstruction, decreased ventilatory capacity, and restrictive impairment by approximately 50%. Changing from the 2.5th percentile, the previously used lower limit of normal, to the 5th percentile recommended by the American Thoracic Society/European Respiratory Society will not increase the prevalence of abnormal findings in the implementation of spirometry reference values.

Age Dependency of GLI Reference Values Compared with Paediatric Lung Function Data in Two German Studies (GINIplus and LUNOKID)

A hallmark of the newly published GLI (Global Lungs Initiative) spirometric reference values is their "all-age" (3-95yr) predictive power, accomplished by incorporating non-linear age dependencies into modelling parameters. This modelling strategy is especially promising for the age range of puberty; however, the performance of GLI-values for adolescents is currently unknown. We calculated GLI-based z-scores for children/adolescents without apparent respiratory diseases from two different German studies, LUNOKID (N = 1943, 4-19 years) and GINIplus (N = 1042, 15 years) and determined the goodness of fit for specific age groups. We defined fit sufficient if the absolute mean of z-scores was <0.5. For children (<10yr) the mean GLI-based z-scores for FEV1 and FVC reached a good fit with mean z-scores for FEV1 between -0.11 and 0.01 and mean z-scores for FVC between 0.01 and 0.16, but larger deviations were observed in adolescents, especially boys (mean z-score -0.58 for FEV1 and -0.57 for FVC in GINIplus). The fit for FEV1/FVC was sufficient. GLI reference values provided reasonable estimates for the individuals enrolled in our studies, which span the age range of lung growth and development. However, we found that GLI-predictions overestimated lung volumes, especially those for German adolescent boys, which may, left unrecognised, lead to erroneous diagnosis of lung disease. Caution should be taken when applying these reference values to epidemiologic studies.

Applicability of the Global Lung Initiative 2012 Reference Values for Spirometry for Longitudinal Data of Elderly Women

Background and Objectives

Lung function depends nonlinearly on age and height, so that the use of age and height specific reference values is required. The widely used age and height specific GLI (Global Lung Initiative) z-scores derived from cross-sectional data, however, have not been proven for validity in an elderly population or for longitudinal data. Therefore, we aimed to test their validity in a population of elderly women followed prospectively for more than 20 years.

Methods

We used spirometric data (forced expiratory volume in 1 second (FEV₁) and forced vital capacity (FVC) and FEV₁/FVC) from the SALIA cohort of German women (baseline: 1985–1994 (aged 55 years), follow-up: 2008/2009 and 2012/2013). We calculated GLI-z-scores for baseline and follow-up examination separately (cross-sectional evaluation) and individual differences in z-scores between baseline and follow-up (longitudinal evaluation) for healthy never-smoking women.

Results

GLI reference values for FEV₁, FVC and FEV₁/FVC were cross-sectionally and longitudinally equivalent with our SALIA data. The mean change in z-scores between baseline and follow-up was 0.33 for FEV₁, 0.38 for FVC and -0.10 for FEV₁/FVC.

Conclusions

In conclusion, GLI z-scores fit cross-sectionally and longitudinally with FEV₁, FVC and FEV₁/FVC measured in women from Germany which indicates that they can be used in longitudinal association analyses.