Predictors of lung function trajectories in population-based studies: A systematic review

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.

Lung function trajectories from school age to adulthood and their relationship with markers of cardiovascular disease risk

RATIONALE

Lung function in early adulthood is associated with subsequent adverse health outcomes.

OBJECTIVES

To ascertain whether stable and reproducible lung function trajectories can be derived in different populations and investigate their association with objective measures of cardiovascular structure and function.

METHODS

Using latent profile modelling, we studied three population-based birth cohorts with repeat spirometry data from childhood into early adulthood to identify trajectories of forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC). We used multinomial logistic regression models to investigate early-life predictors of the derived trajectories. We then ascertained the extent of the association between the derived FEV1/FVC trajectories and blood pressure and echocardiographic markers of increased cardiovascular risk and stroke in ~3200 participants at age 24 years in one of our cohorts.

RESULTS

We identified four FEV1/FVC trajectories with strikingly similar latent profiles across cohorts (pooled N=6377): above average (49.5%); average (38.3%); below average (10.6%); and persistently low (1.7%). Male sex, wheeze, asthma diagnosis/medication and allergic sensitisation were associated with trajectories with diminished lung function in all cohorts. We found evidence of an increase in cardiovascular risk markers ascertained by echocardiography (including left ventricular mass indexed to height and carotid intima-media thickness) with decreasing FEV1/FVC (with p values for the mean crude effects per-trajectory ranging from 0.10 to p<0.001). In this analysis, we considered trajectories as a pseudo-continuous variable; we confirmed the assumption of linearity in all the regression models.

CONCLUSIONS

Childhood lung function trajectories may serve as predictors in the development of not only future lung disease, but also the cardiovascular disease and multimorbidity in adulthood.

Distinct trajectories of lung function from childhood to mid-adulthood

RATIONALE

Life course trajectories of lung function development and decline influence the risk for lung disease but are poorly documented.

OBJECTIVE

To document lung function trajectories from childhood to mid-adult life.

METHODS

We modelled forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC at ages 9, 11, 13, 15, 18, 21, 26, 32, 38 and 45 years from a population-based cohort using latent profile analysis to identify distinct subgroups of participants with similar lung function trajectories. Regression analyses were used to assess associations between the trajectories, early life factors and postbronchodilator airflow obstruction at age 45.

RESULTS

Among 865 participants with ≥6 measures of lung function, we identified 10 distinct FEV1 trajectories. Most were approximately parallel except for a childhood airway hyper-responsiveness-related persistently low trajectory (3% of study population); two accelerated-decline trajectories, one of which (8%) was associated with smoking and higher adult body mass index (BMI) and a catch-up trajectory (8%). Findings for FEV1/FVC trajectories were similar. Nine trajectories were identified for FVC: most were also approximately parallel except for a higher BMI-related accelerated-decline trajectory. The three FEV1 trajectories leading to the lowest FEV1 values comprised 19% of the cohort but contributed 55% of airflow obstruction at age 45.

CONCLUSIONS

Lung function trajectories to mid-adult life are largely established before adolescence, with a few exceptions: a childhood airway hyper-responsiveness-related persistently low trajectory, which starts low and gets worse with age, and accelerated adult decline trajectories associated with smoking and obesity. Adverse trajectories are associated with a high risk of airflow obstruction in mid-adult life.

Longitudinal tracking of intrabreath respiratory impedance in preschool children

BACKGROUND

Longitudinal measurements of intrabreath respiratory impedance (Zrs) in preschool-aged children may be able to distinguish abnormal lung function trajectories in children with a history of wheezing compared to healthy ones.

METHODS

Children from a prospective, longitudinal community-based cohort performed annual intrabreath oscillometry (IB-OSC) measurements from age 3- to 7-years. IB-OSC was performed using a single 10 Hz sinusoid while clinically asymptomatic. Linear mixed-effects models were developed to explore the effects of wheezing phenotypes, growth, and sex on seven IB-OSC outcome variables over time: resistance at end-expiration (ReE), resistance at end-inspiration (ReI), the tidal change in resistance (∆R=ReE-ReI), reactance at end-expiration (XeE), reactance at end-inspiration (XeI), the tidal change in reactance (∆X=XeE-XeI), and ∆X normalized by tidal volume (∆X/VT).

RESULTS

Eighty-five children produced 374 acceptable IB-OSC measurements. Subjects were classified into one of three wheeze groups: never (n = 36), transient (n = 34), or persistent (n = 15). After adjusting for height, children with persistent wheezing, compared to those who never wheezed, had +0.814 hPa s L-1 ReE (95% confidence interval [CI] +0.178 to +1.451, p = 0.015), -0.792 hPa s L-1 XeE (95% CI -1.203 to -0.381, p = 0.003), -0.538 hPa s L-1 ∆X (95% CI -0.834 to -0.242, p = 0.007) and -1.672 hPa s L-2 ∆X/VT (95% CI -2.567 to -0.777, p < 0.001). Increasing height had a significant effect on all IB-OSC resistance and reactance variables when adjusted for the effect of preschool wheezing.

CONCLUSIONS

IB-OSC is feasible for tracking lung function growth in preschool-aged children and may allow abnormal lung function to be identified early in asymptomatic preschoolers with a history of persistent wheezing.

Treatable traits in pre-COPD: Time to extend the treatable traits paradigm beyond established disease

To date, the treatable traits (TTs) approach has been applied in the context of managing diagnosed diseases. TTs are clinical characteristics and risk factors that can be identified clinically and/or biologically, and that merit treatment if present. There has been an exponential increase in the uptake of this approach by both researchers and clinicians. Realizing the potential of the TTs approach to pre-clinical disease, this expert review proposes that it is timely to consider acting on TTs present before a clinical diagnosis is made, which might help to prevent development of the full disease. Such an approach is ideal for diseases where there is a long pre-clinical phase, such as in chronic obstructive pulmonary disease (COPD). The term 'pre-COPD' has been recently proposed to identify patients with respiratory symptoms and/or structural or functional abnormalities without airflow limitation. They may eventually develop airflow limitation with time but patients with pre-COPD are likely to have traits that are already treatable. This review first outlines the contribution of recently generated knowledge into lifetime lung function trajectories and the conceptual framework of 'GETomics' to the field of pre-COPD. GETomics is a dynamic and cumulative model of interactions between genes and the environment throughout the lifetime that integrates information from multi-omics to understand aetiology and mechanisms of diseases. This review then discusses the current evidence on potential TTs in pre-COPD patients and makes recommendations for practice and future research. At a broader level, this review proposes that introducing the TTs in pre-COPD may help reenergize the preventive approaches to health and diseases.

Suboptimal Response to Biologics in Severe Asthma-A Marker of Humoral Immunodeficiencies

BACKGROUND

Asthmatic patients with antibody deficiencies (AD) have more severe disease and higher risk of exacerbations. No data exist about the efficacy of biologics in severe asthma (SA) patients with AD.

OBJECTIVE

To evaluate the efficacy of biologics in SA patients with and without AD.

METHODS

A case-control real-life study was conducted including 68 patients divided into 2 groups: group 1 with SA-AD and group 2 with SA.

RESULTS

Treatment with biologics for 6 months was effective for decreasing the number of exacerbations, hospitalizations, and emergency department (ED) visits and improving the Asthma Control Questionnaire (ACQ) score; biologics also proved a systemic corticosteroid-sparing effect. Despite benefits, the number of exacerbations, hospitalizations, and ED visits, the mean ACQ score, and the cumulative dose of systemic corticosteroids remain higher in group 1 than in group 2, with lower lung function parameters. The rates of responses in group 1 were inferior to those in group 2, with a decrease by ≥50% of exacerbation rate in 76% versus 97% of patients (P = .006), no hospitalization in 44% versus 91% of patients (P < .001), no ED visit in 56% versus 82% of patients (P = .018), a significant improvement of the ACQ score by ≥0.5 in 68% versus 100% of patients (P < .001), and an increase of forced expiratory volume in the first second by >10% in 32% versus 65% of patients (P = .007).

CONCLUSIONS

Despite evident benefits, SA patients with AD have suboptimal responses to biologics compared with those immunocompetent. A multidisciplinary approach is necessary to optimize the management of these patients in practice.

What is pre-COPD and do we know how to treat it?

INTRODUCTION

Chronic Obstructive Pulmonary Disease (COPD) is one of the leading causes of morbidity and mortality worldwide. The lung damage in COPD is associated with an enhanced chronic inflammatory response in the airways and lung tissue to harmful particles or gases. Early detection and treatment of COPD can help manage symptoms and slow the progression of the disease.

AREAS COVERED

Status of knowledge regarding early diagnosis, definition of pre-COPD, possible new tools for early diagnosis, possibilities of early treatment, and the results of studies in this population are discussed. Literature search (2014-2024) was done in PubMed, EMBASE, and WoS databases using the keywords COPD, early diagnosis, treatment, smoking, prevention; with additional search of literature in found articles.

EXPERT OPINION

No early case-finding programs have been proposed or validated, so we still have many patients diagnosed in the late stage of the disease. Clinically manifest COPD is characterized as typically progressive and irreversible with current therapeutic options. If we aim to reduce the mortality and morbidity from COPD we should target these steps: Prevention; Early diagnosis; Form registries of persons at risk for COPD development; Diagnose preclinical COPD; and discover new preventive therapeutic interventions.

Lower respiratory tract infections in children with congenital lung abnormalities

OBJECTIVE

We aimed to determine if the incidence of lower respiratory tract infections (LRTI) among children with asymptomatic, observationally managed congenital lung abnormalities (CLA) differed from that of symptomatic patients who underwent surgery. Second, we sought to compare the pre- and post-resection incidence of LRTI in patients who underwent surgery.

METHODS

This retrospective cohort study included patients born between 1999 and 2021 with CLA confirmed by CT scan who were enrolled in a prospective longitudinal follow-up program. The LRTI incidence rates at 1, 2, 5, 8, and 12 years were compared between surgically and observationally managed patients using incidence rate ratios (IRR). Differences in pre- and post-resection LRTI incidence rates among patients who underwent CLA-related surgery were assessed through IRR.

RESULTS

Among 217 included patients, 81 (37%) had undergone surgery and 136 (63%) had been observationally managed. The LRTI incidence rates did not significantly differ at any follow-up moment between the surgical and observational groups. Among the children who underwent CLA-related surgery, the pre-resection LRTI incidence rates were significantly higher than the post-resection LRTI incidence rates (IRR of 3.57, 95% confidence interval: [2.00; 6.33], p < .001).

CONCLUSION

We could not demonstrate differences in LRTI incidence throughout childhood between patients with surgically and observationally managed CLA. We recommend discussing cases of LRTI in patients with CLA in a multidisciplinary setting, using additional diagnostics such as chest X-ray to screen for CLA involvement, enabling a well-considered decision on surgical resection of the lesion.

Long-term trajectories of peak expiratory flow rate in older men and women show linear decline mainly determined by baseline levels

BACKGROUND

Peak expiratory flow rate (PEFR) predicts mortality and other negative health outcomes. However, little evidence exists on how PEFR changes with ageing and how trajectories of change differ among older people.

AIMS

To identify trajectories of PEFR in older men and women, and to study characteristics associated with these trajectories.

METHODS

Data from the Longitudinal Aging Study Amsterdam were used, an ongoing cohort study in a representative sample of Dutch older men and women. PEFR was assessed using the Mini-Wright peak flow meter across a 13-year follow-up in 991 men and 1107 women. Trajectories were analyzed using Latent Class Growth Analysis.

RESULTS

Mean age was 72.5 (SD 8.4) in men and 72.4 (SD 8.4) in women. In men, three declining trajectories were identified, i.e. high, intermediate and low, with prevalences of 30%, 46% and 24%, respectively. In women, two declining trajectories were identified, i.e. high and low, with prevalences of 62 and 38%. All trajectories showed linear decline and differed mostly with regard to their intercept. Significant differences between trajectories with regard to baseline demographic, health and lifestyle characteristics were observed, e.g., men and women in the low PEFR trajectory were older, had more chronic diseases, and were more often smoker.

DISCUSSION AND CONCLUSIONS

Trajectories in both men and women differ mainly in baseline level of PEFR and not in rate of decline over time. Therefore, one PEFR measurement might be sufficient to give an indication of the trajectory that an older adult is likely to follow.

Lung Disease and Social Justice: Chronic Obstructive Pulmonary Disease as a Manifestation of Structural Violence

Lung health, the development of lung disease, and how well a person with lung disease is able to live all depend on a wide range of societal factors. These systemic factors that adversely affect people and cause injustice can be thought of as "structural violence." To make the causal processes relating to chronic obstructive pulmonary disease (COPD) more apparent, and the responsibility to interrupt or alleviate them clearer, we have developed a taxonomy to describe this. It contains five domains: 1) avoidable lung harms (processes impacting lung development, processes that disadvantage lung health in particular groups across the life course), 2) diagnostic delay (healthcare factors; norms and attitudes that mean COPD is not diagnosed in a timely way, denying people with COPD effective treatment), 3) inadequate COPD care (ways in which the provision of care for people with COPD falls short of what is needed to ensure they are able to enjoy the best possible health, considered as healthcare resource allocation and norms and attitudes influencing clinical practice), 4) low status of COPD (ways COPD as a condition and people with COPD are held in less regard and considered less of a priority than other comparable health problems), and 5) lack of support (factors that make living with COPD more difficult than it should be, i.e., socioenvironmental factors and factors that promote social isolation). This model has relevance for policymakers, healthcare professionals, and the public as an educational resource to change clinical practices and priorities and stimulate advocacy and activism with the goal of the elimination of COPD.

Lung-function trajectories: relevance and implementation in clinical practice

Lung development starts in utero and continues during childhood through to adolescence, reaching its peak in early adulthood. This growth is followed by gradual decline due to physiological lung ageing. Lung-function development can be altered by several host and environmental factors during the life course. As a result, a range of lung-function trajectories exist in the population. Below average trajectories are associated with respiratory, cardiovascular, metabolic, and mental health comorbidities, as well as with premature death. This Review presents progressive research into lung-function trajectories and assists the implementation of this knowledge in clinical practice as an innovative approach to detect poor lung health early, monitor respiratory disease progression, and promote lung health. Specifically, we propose that, similar to paediatric height and weight charts used globally to monitor children's growth, lung-function charts could be used for both children and adults to monitor lung health status across the life course. To achieve this proposal, we introduce our free online Lung Function Tracker tool. Finally, we discuss challenges and opportunities for effective implementation of the trajectory concept at population level and outline an agenda for crucial research needed to support such implementation.

The effect of body compartments on lung function in childhood and adolescence

BACKGROUND

There is an association between body composition and lung function, assessed by spirometry, but the effects of body compartments on static lung volumes and its changes during lung growth remain to be explored. We aimed to investigate the association of appendicular lean mass, reflecting skeletal muscle mass, and fat mass on forced and static lung function measures in childhood and adolescence.

METHODS

In total, 1489 children and adolescents (6-18 years) of the observational, longitudinal (first and second visit within 4 years), general population-based LEAD study have been investigated. The association of appendicular lean mass and fat mass indices (ALMI and FMI; assessed by dual-energy X-ray absorptiometry) on lung function by spirometry (FEV1, FVC) and body plethysmography (TLC, RV, FRC) was investigated cross-sectionally. Longitudinal associations between lung function and body compartment changes between the two visits were analyzed.

FINDINGS

The ALMI is positively associated with FEV1, FVC, and TLC. Contrary, FMI is inversely associated with lung function measures including FRC and RV. During the phase of lung growth, higher gain in muscle mass is associated with higher increases of FVC and TLC.

INTERPRETATION

This study demonstrates the different effects of muscle and fat mass on forced expiratory and static lung volumes. Achieving and maintaining muscle mass in childhood and adolescence might become an important preventive strategy for lung health in adulthood.

Spirometric patterns in young and middle-aged adults: a 20-year European study

BACKGROUND

Understanding the natural history of abnormal spirometric patterns at different stages of life is critical to identify and optimise preventive strategies. We aimed to describe characteristics and risk factors of restrictive and obstructive spirometric patterns occurring before 40 years (young onset) and between 40 and 61 years (mid-adult onset).

METHODS

We used data from the population-based cohort of the European Community Respiratory Health Survey (ECRHS). Prebronchodilator forced expiratory volume in one second (FEV1) and forced vital capacity (FVC) were assessed longitudinally at baseline (ECRHS1, 1993-1994) and again 20 years later (ECRHS3, 2010-2013). Spirometry patterns were defined as: restrictive if FEV1/FVC≥LLN and FVC<10th percentile, obstructive if FEV1/FVC

RESULTS

Among 3502 participants (mean age=30.4 (SD 5.4) at ECRHS1, 50.4 (SD 5.4) at ECRHS3), 2293 (65%) had a normal, 371 (11%) a young restrictive, 301 (9%) a young obstructive, 187 (5%) a mid-adult onset restrictive and 350 (10%) a mid-adult onset obstructive spirometric pattern. Being lean/underweight in childhood and young adult life was associated with the occurrence of the young spirometric restrictive pattern (relative risk ratio (RRR)=1.61 95% CI=1.21 to 2.14, and RRR=2.43 95% CI=1.80 to 3.29; respectively), so were respiratory infections before 5 years (RRR=1.48, 95% CI=1.05 to 2.08). The main determinants for young obstructive, mid-adult restrictive and mid-adult obstructive patterns were asthma, obesity and smoking, respectively.

CONCLUSION

Spirometric patterns with onset in young and mid-adult life were associated with distinct characteristics and risk factors.

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Key Words

• COPD epidemiology
• Clinical Epidemiology

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MESH Headings

• Middle Aged
• Young Adult
• Humans
• Adult
• Pulmonary Disease, Chronic Obstructive
• Spirometry
• Respiratory Function Tests
• Asthma/complications
• Risk Factors
• Forced Expiratory Volume
• Vital Capacity

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Grants

• CEX2018-000806-S Spanish Ministry of Science and Innovation

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Affiliation(s)

Anne-Elie Carsin ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain Biometrics, RTI-Health Solutions, Barcelona, Spain
Judith Garcia-Aymerich ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Simone Accordini Unit of Epidemiology and Medical Statistics, Department of Diagnostics and Public Health, University of Verona, Verona, Italy
Shyamali Dharmage Allergy and Lung Health Unit, School of Population and Global Health, The University of Melbourne, Parkville, Victoria, Australia
Bénédicte Leynaert Université Paris-Saclay, UVSQ, Univ Paris-Sud, Inserm, INSERM, Paris, France
Marti de Las Heras ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Lidia Casas Social Epidemiology and Health Policy, Department of Family Medicine and Population Health, University of Antwerp, Antwerpen, Belgium Institute for Environment and Sustainable Development (IMDO), University of Antwerp, Antwerpen, Belgium
Seraina Caviezel Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
Pascal Demoly Département de Pneumologie et Addictologie, University Hospital of Montpellier, Montpellier, France IDESP, University of Montpellier - Inserm UMR UA11, Montpellier, France
Bertil Forsberg Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
Thorarinn Gislason Department of Sleep, Landspitali University Hospital, Reykjavik, Iceland Medical Faculty, University of Iceland, Iceland, Iceland
Angelo Guido Corsico Department of Internal Medicine and Therapeutics, University of Pavia, Italy, Italy Division of Respiratory Diseases, Fondazione IRCCS Policlinico San Matteo-University of Pavia, Pavia, Italy
Christer Janson Department of Medical Sciences, Respiratory, Allergy and Sleep Research, Uppsala University, Uppsala, Sweden
Rain Jogi Lung Clinic, Tartu University Hospital, Tartu, Estonia
Jesús Martínez-Moratalla Faculty of Medicine of Albacete, General University Hospital of Albacete, Albacete, Spain
Dennis Nowak Institute and Clinic for Occupational and Environmental Medicine, University Hospital, LMU Munich, Comprehensive Pneumology Centre Munich, member DZL, German Centre for Lung Research, Munich, Germany
Leopoldo Palacios Gómez Distrito Sanitario Huelva-Costa, Huelva, Spain
Isabelle Pin Department of Pediatrics, CHU de Grenoble Alpes, Grenoble, France Inserm, UMR 1209, Institute for Advanced Biosciences, Grenoble, France
Nicole Probst-Hensch Epidemiology and Public Health, Swiss Tropical and Public Health Institute, Basel, Switzerland
Chantal Raherison-Semjen Inserm, UMR 1219, Université de Bordeaux, Bordeaux, France
Giulia Squillacioti Department of Public Health and Pediatrics, University of Turin, Torino, Piemonte, Italy
Cecilie Svanes Centre for International Health, Department of Global Public Health and Primary Care, University of Bergen, Bergen, Norway Department of Occupational Medicine, Haukeland University Hospital, Bergen, Norway
Kjell Torén Department of Occupational and Environmental, School of Public Health and Community Medicine, Institute of Medicine, Sahlgrenska Academy at University of Gothenburg, Gothenburg, Sweden Department of Occupational and Environmental Medicine, Sahlgrenska University Hospital, Gothenburg, Sweden
Isabel Urrutia Pulmonology Department, Galdakao Hospital, Biocruces Bizkaia, Spain
Ismael Huerta Epidemiological Surveillance Section, Directorate General of Public Health, Oviedo, Spain
Josep Maria Anto ISGlobal, Campus mar, Barcelona, Catalunya, Spain Universita Pompeu Fabra (UPF), Barcelona, Spain CIBER Epidemiología y Salud Pública (CIBERESP), Spain, Spain
Debbie Jarvis National Heart and Lung Institute, Imperial College, London, UK
Stefano Guerra ISGlobal, Campus mar, Barcelona, Catalunya, Spain Asthma and Airway Disease Research Center, University of Arizona, Tucson, Arizona, USA

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Clinical relevance of lung function trajectory clusters in middle-aged and older adults

Background

The determinants and health outcomes of lung function trajectories in adults among the general population are poorly understood. We aimed to identify and characterise clusters of lung function trajectories in adults aged ≥45 years.

Methods

Gaussian finite-mixture modelling was applied to baseline and annualised change of forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio z-scores in participants of the Rotterdam Study, a prospective population-based cohort study, with repeated spirometry (n=3884; mean±sd age 64.7±8.9 years). Longitudinal outcomes were all-cause mortality, respiratory outcomes (symptoms, COPD (FEV1/FVC <0.7 in absence of asthma), preserved ratio impaired spirometry (PRISm; FEV1/FVC ≥0.7 and FEV1 or FVC <80%)), smoking cessation and weight changes. Independent risk factors, including genetics, were identified by multiple logistic regression.

Results

We identified eight trajectory clusters, with the reference group having persistently normal spirometry (prevalence 42.8%). Three clusters showed higher mortality, adjusted for confounders: 1) the persistently low FEV1 cluster (prevalence 6.8%, hazard ratio (HR) 1.71, 95% CI 1.37-2.13); 2) rapid FEV1 decliners (prevalence 4.6%, HR 1.48, 95% CI 1.10-1.99); and 3) FVC decliners (prevalence 3.7%, HR 1.49, 95% CI 1.09-2.03). In contrast, FVC improvers (prevalence 6.7%, HR 0.61, 95% CI 0.41-0.90) and persistently high FEV1 (prevalence 29.2%, HR 0.82, 95% CI 0.69-0.98) were protective trajectory clusters. Clusters were characterised by differences in genetic predisposition (polygenic scores of FEV1 and FEV1/FVC), demographics, cigarette smoking, respiratory symptoms (chronic cough, wheezing and dyspnoea), cardiovascular factors (body mass index, hypertension and heart failure) and serum C-reactive protein levels. Frailty, weight changes and the development of respiratory symptoms, COPD and PRISm were significantly associated with trajectory clusters.

Conclusions

This study reveals clinically relevant lung function trajectory clusters in older adults of the general population.

ERS International Congress 2023: highlights from the Paediatrics Assembly

Respiratory health in children is essential for general wellbeing and healthy development in the short and long term. It is well known that many respiratory diseases in adulthood have their origins in early life, and therefore research on prevention of respiratory diseases and management of children with respiratory diseases will benefit patients during the full life course. Scientific and clinical advances in the field of respiratory health are moving at a fast pace. This article summarises some of the highlights in paediatric respiratory medicine presented at the hybrid European Respiratory Society (ERS) International Congress 2023 which took place in Milan (Italy). Selected sessions are summarised by Early Career Members of the Paediatrics Assembly (Assembly 7) under the supervision of senior ERS officers, and cover a wide range of research areas in children, including respiratory physiology and sleep, asthma and allergy, cystic fibrosis, respiratory infection and immunology, neonatology and intensive care, respiratory epidemiology and bronchology.

Prenatal exposure to metal mixtures and lung function in children from the New Hampshire birth cohort study

Prenatal exposure to metals/metalloids, even at common US population levels, may pose risks to fetal health, and affect children's lung function. Yet, the combined effects of simultaneous prenatal exposures on children's lung function remain largely unexplored. This study analyzed 11 metals (As speciation, Cd, Co, Cu, Mo, Ni, Pb, Sb, Se, Sn, Zn) in maternal urine during weeks 24-28 of gestation and evaluated lung function, including forced vital capacity (FVC) and forced expiratory volume in the first second of expiration (FEV1), in 316 US mother-child pairs at around age 7. We used Bayesian Kernel Machine Regression (BKMR), weighted quantile sum regression (WQSR), and multiple linear regression to examine the association between metal mixture exposure and children's lung function, adjusting for maternal smoking, child age, sex, and height. In BKMR models assessing combined exposure effects, limited evidence of metal non-linearity or interactions was found. Nevertheless, Co, As species, and Pb showed a negative association, while Mo exhibited a positive association with children's FVC and FEV1, with other metals held constant at their medians. The weighted index, from WQSR analysis assessing the cumulative impact of all metals, highlighted prenatal Mo with the highest positive weight, and Co, As, and Sb with the most substantial negative weights on children's FVC and FEV1. Urinary Co and Pb were negatively associated with FVC (β = -0.09, 95% confidence interval (CI) (-0.18; -0.01) and β = -0.07, 95% CI (-0.13; 0.00), respectively). Co was also negatively associated with FEV1 (β = -0.09, 95% CI (-0.18; 0.00). There was a negative association between As and FVC, and a positive association between Mo and both FVC and FEV1, though with wide confidence intervals. Our findings suggest that prenatal trace element exposures may impact children's lung function, emphasizing the importance of reducing toxic exposures and maintaining adequate nutrient levels.

Regenerative and translational medicine in COPD: hype and hope

COPD is a common, preventable and usually progressive disease associated with an enhanced chronic inflammatory response in the airways and lung, generally caused by exposure to noxious particles and gases. It is a treatable disease characterised by persistent respiratory symptoms and airflow limitation due to abnormalities in the airways and/or alveoli. COPD is currently the third leading cause of death worldwide, representing a serious public health problem and a high social and economic burden. Despite significant advances, effective clinical treatments have not yet been achieved. In this scenario, cell-based therapies have emerged as potentially promising therapeutic approaches. However, there are only a few published studies of cell-based therapies in human patients with COPD and a small number of ongoing clinical trials registered on clinicaltrials.gov Despite the advances and interesting results, numerous doubts and questions remain about efficacy, mechanisms of action, culture conditions, doses, timing, route of administration and conditions related to homing and engraftment of the infused cells. This article presents the state of the art of cell-based therapy in COPD. Clinical trials that have already been completed and with published results are discussed in detail. We also discuss the questions that remain unanswered about cell-based regenerative and translational medicine for COPD.

Residential greenspace and lung function decline over 20 years in a prospective cohort: The ECRHS study

BACKGROUND

The few studies that have examined associations between greenspace and lung function in adulthood have yielded conflicting results and none have examined whether the rate of lung function decline is affected.

OBJECTIVE

We explored the association between residential greenspace and change in lung function over 20 years in 5559 adults from 22 centers in 11 countries participating in the population-based, international European Community Respiratory Health Survey.

METHODS

Forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) were measured by spirometry when participants were approximately 35 (1990-1994), 44 (1999-2003), and 55 (2010-2014) years old. Greenness was assessed as the mean Normalized Difference Vegetation Index (NDVI) in 500 m, 300 m, and 100 m circular buffers around the residential addresses at the time of lung function measurement. Green spaces were defined as the presence of agricultural, natural, or urban green spaces in a circular 300 m buffer. Associations of these greenspace parameters with the rate of lung function change were assessed using adjusted linear mixed effects regression models with random intercepts for subjects nested within centers. Sensitivity analyses considered air pollution exposures.

RESULTS

A 0.2-increase (average interquartile range) in NDVI in the 500 m buffer was consistently associated with a faster decline in FVC (-1.25 mL/year [95% confidence interval: -2.18 to -0.33]). These associations were especially pronounced in females and those living in areas with low PM10 levels. We found no consistent associations with FEV1 and the FEV1/FVC ratio. Residing near forests or urban green spaces was associated with a faster decline in FEV1, while agricultural land and forests were related to a greater decline in FVC.

CONCLUSIONS

More residential greenspace was not associated with better lung function in middle-aged European adults. Instead, we observed slight but consistent declines in lung function parameters. The potentially detrimental association requires verification in future studies.

Long-term implications of fetal growth restriction

Fetal growth restriction (FGR), or intrauterine growth restriction (IUGR), is a complication of pregnancy where the fetus does not achieve its genetic growth potential. FGR is characterized by a pathological retardation of intrauterine growth velocity in the curve of intrauterine growth. However, the FGR definition is still debated, and there is a lack of a uniform definition in the literature. True IUGR, compared to constitutional smallness, is a pathological condition in which the placenta fails to deliver an adequate supply of oxygen and nutrients to the developing fetus. Infants with IUGR, compared to appropriately grown gestational age infants, have a significantly higher risk of mortality and neonatal complications with long-term consequences. Several studies have demonstrated how suboptimal fetal growth leads to long-lasting physiological alterations for the developing fetus as well as for the newborn and adult in the future. The long-term effects of fetal growth retardation may be adaptations to poor oxygen and nutrient supply that are effective in the fetal period but deleterious in the long term through structural or functional alterations. Epidemiologic studies showed that FGR could be a contributing factor for adult chronic diseases including cardiovascular disease, metabolic syndrome, diabetes, respiratory diseases and impaired lung function, and chronic kidney disease. In this review we discussed pathophysiologic mechanisms of FGR-related complications and potential preventive measures for FGR.

Analysis of influencing factors and a predictive model of small airway dysfunction in adults

BACKGROUND

Small airway dysfunction (SAD) is a widespread but less typical clinical manifestation of respiratory dysfunction. In lung diseases, SAD can have a higher-than-expected impact on lung function. The aim of this study was to explore risk factors for SAD and to establish a predictive model.

METHODS

We included 1233 patients in the pulmonary function room of TangDu Hospital from June 2021 to December 2021. We divided the subjects into a small airway disorder group and a non-small airway disorder group, and all participants completed a questionnaire. We performed univariate and multivariate analyses to identify the risk factors for SAD. Multivariate logistic regression was performed to construct the nomogram. The performance of the nomogram was assessed and validated by the Area under roc curve (AUC), calibration curves, and Decision curve analysis (DCA).

RESULTS

One. The risk factors for small airway disorder were advanced age (OR = 7.772,95% CI 2.284-26.443), female sex (OR = 1.545,95% CI 1.103-2.164), family history of respiratory disease (OR = 1.508,95% CI 1.069-2.126), history of occupational dust exposure (OR = 1.723,95% CI 1.177-2.521), history of smoking (OR = 1.732,95% CI 1.231-2.436), history of pet exposure (OR = 1.499,95% CI 1.065-2.110), exposure to O₃ (OR = 1.008,95% CI 1.003-1.013), chronic bronchitis (OR = 1.947,95% CI 1.376-2.753), emphysema (OR = 2.190,95% CI 1.355-3.539) and asthma (OR = 7.287,95% CI 3.546-14.973). 2. The AUCs of the nomogram were 0.691 in the training set and 0.716 in the validation set. Both nomograms demonstrated favourable clinical consistency. 3.There was a dose‒response relationship between cigarette smoking and SAD; however, quitting smoking did not reduce the risk of SAD.

CONCLUSION

Small airway disorders are associated with age, sex, family history of respiratory disease, occupational dust exposure, smoking history, history of pet exposure, exposure to O₃, chronic bronchitis, emphysema, and asthma. The nomogram based on the above results can effectively used in the preliminary risk prediction.

Early Origins of Chronic Obstructive Pulmonary Disease: Prenatal and Early Life Risk Factors

The main risk factor for chronic obstructive pulmonary disease (COPD) is active smoking. However, a considerable amount of people with COPD never smoked, and increasing evidence suggests that adult lung disease can have its origins in prenatal and early life. This article reviews some of the factors that can potentially affect lung development and lung function trajectories throughout the lifespan from genetics and prematurity to respiratory tract infections and childhood asthma. Maternal smoking and air pollution exposure were also analyzed among the environmental factors. The adoption of preventive strategies to avoid these risk factors since the prenatal period may be crucial to prevent, delay the onset or modify the progression of COPD lung disease throughout life.

HOW TO IDENTIFY SUBGROUPS IN LONGITUDINAL CLINICAL DATA: TREATMENT RESPONSE PATTERNS IN PATIENTS WITH A SHORTENED DENTAL ARCH

BACKGROUND

When dental patients seek care, treatments are not always successful,that is patients' oral health problems are not always eliminated or substantially reduced. Identifying these patients (treatment non-responders) is essential for clinical decision-making. Group-based trajectory modeling (GBTM) is rarely used in dentistry, but a promising statistical technique to identify non-responders in particular and clinical distinct patient groups in general in longitudinal data sets.

AIM

Using group-based trajectory modeling, this study aimed to demonstrate how to identify oral health-related quality of life (OHRQoL) treatment response patterns by the example of patients with a shortened dental arch (SDA).

METHODS

This paper is a secondary data analysis of a randomized controlled clinical trial. In this trial SDA patients received partial removable dental prostheses replacing missing teeth up to the first molars (N = 79) either or the dental arch ended with the second premolar that was present or replaced by a cantilever fixed dental prosthesis (N = 71). Up to ten follow-up examinations (1-2, 6, 12, 24, 36, 48, 60, 96, 120, and 180 months post-treatment) continued for 15 years. The outcome OHRQoL was assessed with the 49-item Oral Health Impact Profile (OHIP). Exploratory GBTM was performed to identify treatment response patterns.

RESULTS

Two response patterns could be identified - "responders" and "non-responders." Responders' OHRQoL improved substantially and stayed primarily stable over the 15 years. Non-responders' OHRQoL did not improve considerably over time or worsened. While the SDA treatments were not related to the 2 response patterns, higher levels of functional, pain-related, psychological impairment in particular, and severely impaired OHRQoL in general predicted a non-responding OHRQoL pattern after treatment. Supplementary, a 3 pattern approach has been evaluated.

CONCLUSIONS

Clustering patients according to certain longitudinal characteristics after treatment is generally important, but specifically identifying treatment in non-responders is central. With the increasing availability of OHRQoL data in clinical research and regular patient care, GBTM has become a powerful tool to investigate which dental treatment works for which patients.

History of Respiratory Events Prior to a First COPD Diagnosis and Future Exacerbations: A Longitudinal Observational Cohort Database Study in Japan

Background

Little is known about the association between respiratory events prior to diagnosis of chronic obstructive pulmonary disease (COPD) and future clinical outcomes in Japan. We investigated the association between pre-COPD diagnosis respiratory events and the incidence of exacerbations in a cohort of newly diagnosed COPD patients in Japan.

Patients and Methods

Data were retrieved from the JMDC claims database. Patients ≥40 years old with a first COPD diagnosis (≥1 hospitalization or ≥2 outpatient claims for COPD) between 2010 and 2016 were included. The incidence rate (IR) of exacerbations in patients with or without any respiratory event (including lower respiratory tract infection and respiratory failure) in the year preceding diagnosis was compared. A negative binomial model explored the association between pre-diagnosis respiratory event and IR ratio (IRR) of exacerbations.

Results

A total of 20,212 patients newly diagnosed with COPD were identified: 61% male, mean age 55 years (SD 9); of these, 955 (4.7%) had experienced ≥1 respiratory event in the year preceding diagnosis. Median duration of follow-up was 3.3 years during which the IR of exacerbations was 0.31 per patient-year (95% confidence interval [CI] 0.29-0.33) in patients with respiratory event, and 0.11 (95% CI 0.10-0.13) in patients without. The IR for severe exacerbation was nearly 10 times greater in patients with respiratory event versus without. Experiencing respiratory event pre-diagnosis was independently associated with an increased IRR of future moderate-to-severe exacerbation (adjusted IRR, 2.7; 95% CI 2.3-3.1).

Conclusion

Patients experiencing respiratory events in the year preceding COPD diagnosis should be considered at-risk of worse clinical COPD outcomes.

Poor Asthma Control in Schoolchildren May Lead to Lower Lung Function Trajectory from Childhood to Early Adulthood: A Japanese Cohort Study

Purpose

Although childhood asthma is a risk factor for adult lung function disorders, the correlation between childhood asthma control level and lung function growth remains unclear in Japan. The correlation between childhood asthma control and early adulthood lung function growth was investigated in this study.

Patients and Methods

We included 505 children with asthma from the Omuta City Air Pollution-Related Health Damage Cohort Program. The characteristics and lung function of girls and boys aged 6–11 years and 12–17 years were compared between poor and good asthma control groups.

Results

Among the 505 children, 214 (42.4%) showed poor asthma control. The mean percentage forced expiratory volume in 1 second predicted for girls and boys aged 6–11 years (80.2% and 79.2%, respectively) and 12–17 years (80.0% and 81.1%, respectively) in the poor control group was significantly lower than those of girls and boys aged 6–11 years (87.9% and 87.3%, respectively) and 12–17 years (88.1% and 87.8%, respectively) in the good control group. However, a linear regression model did not reveal between-group differences in the slopes of lung function growth for both sexes. Girls (24.6%, P < 0.0001) and boys (24.4%, P = 0.0026) in the poor control group had a significantly higher proportion of young adults with obstructive ventilatory patterns than girls (1.4%) and boys (8.1%) in the good control group.

Conclusion

Our findings revealed that poor childhood asthma control leaded to lung function disorders, which suggest the importance of early asthma control in school children.

Occupational COPD-The most under-recognized occupational lung disease?

Chronic obstructive pulmonary disease (COPD) is caused by exposure to noxious particles and gases. Smoking is the main risk factor, but other factors are also associated with COPD. Occupational exposure to vapours, gases, dusts and fumes contributes to the development and progression of COPD, accounting for a population attributable fraction of 14%. Workplace pollutants, in particular inorganic dust, can initiate airway damage and inflammation, which are the hallmarks of COPD pathogenesis. Occupational COPD is still underdiagnosed, mainly due to the challenges of assessing the occupational component of the disease in clinical settings, especially if other risk factors are present. There is a need for specific education and training for clinicians, and research with a focus on evaluating the role of occupational exposure in causing COPD. Early diagnosis and identification of occupational causes is very important to prevent further decline in lung function and to reduce the health and socio-economic burden of COPD. Establishing details of the occupational history by general practitioners or respiratory physicians could help to define the occupational burden of COPD for individual patients, providing the first useful interventions (smoking cessation, best therapeutic management, etc.). Once patients are diagnosed with occupational COPD, there is a wide international variation in access to specialist occupational medicine and public health services, along with limitations in workplace and income support. Therefore, a strong collaboration between primary care physicians, respiratory physicians and occupational medicine specialists is desirable to help manage COPD patients' health and social issues.

Prenatal Fine Particulate Matter, Maternal Micronutrient Antioxidant Intake, and Early Childhood Repeated Wheeze: Effect Modification by Race/Ethnicity and Sex

Fine particulate matter (PM2.5) potentiates in utero oxidative stress influencing fetal development while antioxidants have potential protective effects. We examined associations among prenatal PM2.5, maternal antioxidant intake, and childhood wheeze in an urban pregnancy cohort (n = 530). Daily PM2.5 exposure over gestation was estimated using a satellite-based spatiotemporally resolved model. Mothers completed the modified Block98 food frequency questionnaire. Average energy-adjusted percentile intake of β-carotene, vitamins (A, C, E), and trace minerals (zinc, magnesium, selenium) constituted an antioxidant index (AI). Maternal-reported child wheeze was ascertained up to 4.1 ± 2.8 years. Bayesian distributed lag interaction models (BDLIMs) were used to examine time-varying associations between prenatal PM2.5 and repeated wheeze (≥2 episodes) and effect modification by AI, race/ethnicity, and child sex. Covariates included maternal age, education, asthma, and temperature. Women were 39% Black and 33% Hispanic, 36% with ≤high school education; 21% of children had repeated wheeze. Higher AI was associated with decreased wheeze in Blacks (OR = 0.37 (0.19-0.73), per IQR increase). BDLIMs identified a sensitive window for PM2.5 effects on wheeze among boys born to Black mothers with low AI (at 33-40 weeks gestation; OR = 1.74 (1.19-2.54), per µg/m3 increase in PM2.5). Relationships among prenatal PM2.5, antioxidant intake, and child wheeze were modified by race/ethnicity and sex.

Can birth weight predict offspring's lung function in adult age? Evidence from two Swedish birth cohorts

BACKGROUND

Associations between birth weight (BW) and adult lung function have been inconsistent and limited to early adulthood. We aimed to study this association in two population-based cohorts and explore if BW, adjusted for gestational age, predicts adult lung function. We also tested adult lung function impairment according to the mis-match hypothesis-small babies growing big as adults.

METHODS

We included 3495 individuals (aged 46.4 ± 5.4 years) from the Malmo Preventive Project (MPP), Sweden, born between 1921 and 1949, and 1401 young to middle-aged individuals (aged 28.6 ± 6.7 years) from the Malmo Offspring Study (MOS) with complete data on BW and gestational age. Adult lung function (forced vital capacity [FVC], forced expiratory volume in one second [FEV1] and the FEV1/FVC-ratio) were analysed as level of impairment (z-score), using multiple linear and logistic regressions.

RESULTS

BW (z-score) did not predict adult lung function in MPP, whereas BW was a significant (p = 0.003) predictor of FEV1 following full adjustment in MOS. For every additional unit increase in BW, children were 0.77 (95% CI 0.65-0.92) times less likely to have impaired adult lung function (FEV1). Moreover, adults born with lower BW (< 3510 g) showed improved lung function (FEV1 and FEV1/FVC in MOS and MPP, respectively) if they achieved higher adult body weight.

CONCLUSIONS

Adults born with lower birth weight, adjusted for gestational age, are more likely to have impaired lung function, seen in a younger birth cohort. Postnatal growth pattern may, however, compensate for low birth weight and contribute to better adult lung function.