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.

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

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

Lung function in young adulthood in relation to moderate-to-late preterm birth.

Background: Moderate-to-late preterm birth (32 to <37 weeks of gestation) has been associated with impaired lung function in adolescence, but data in adulthood and physiological phenotyping beyond spirometry are scarce. We aimed to investigate lung function development from adolescence into young adulthood and to provide physiological phenotyping in individuals born moderate-to-late preterm. Methods: Lung function data from individuals born moderate-to-late preterm (n=110) and term (37 to <42 weeks of gestation, n=1895) in the Swedish birth cohort BAMSE were used for analysis and included dynamic spirometry, fractional exhaled nitric oxide and multiple breath nitrogen wash-out. Data from 16- and 24-year follow-ups were analysed using regression models stratified on sex and adjusted for smoking. Data-driven latent class analysis was used to phenotype moderate-to-late preterm individuals at 24 years, and groups were related to background factors. Results: Males born moderate-to-late preterm had lower forced expiratory volume in 1 s (FEV1) at 24 years of age (-0.28 z-score, p=0.045), compared to males born term. In females, no difference was seen at 24 years, partly explained by a significant catch up in FEV1 between 16 and 24 years (0.18 z-score, p=0.01). Lung function phenotypes described as "asthma-like", "dysanapsis-like" and "preterm reference" were identified within the preterm group. Maternal overweight in early pregnancy was associated with "asthma-like" group membership (OR 3.59, p=0.02). Conclusion: Our results show impaired FEV1 at peak lung function in males born moderate-to-late preterm, while females born moderate-to-late preterm had significant catch up between the ages of 16 and 24 years. Several phenotypes of lung function impairment exist in individuals born moderate-to-late preterm.

Unravelling the respiratory health path across the lifespan for survivors of preterm birth.

Many survivors of preterm birth will have abnormal lung development, reduced peak lung function and, potentially, an increased rate of physiological lung function decline, each of which places them at increased risk of chronic obstructive pulmonary disease across the lifespan. Current rates of preterm birth indicate that by the year 2040, around 50 years since the introduction of surfactant therapy, more than 700 million individuals will have been born prematurely-a number that will continue to increase by about 15 million annually. In this Personal View, we describe current understanding of the impact of preterm birth on lung function through the life course, with the aim of putting this emerging health crisis on the radar for the respiratory community. We detail the potential underlying mechanisms of prematurity-associated lung disease and review current approaches to prevention and management. Furthermore, we propose a novel way of considering lung disease after preterm birth, using a multidimensional model to determine individual phenotypes of lung disease-a first step towards optimising management approaches for prematurity-associated lung disease.

Post COVID-19 symptoms are common, also among young adults in the general population.

Post coronavirus disease-19 (post COVID-19) is mainly studied in clinical populations and less is known about post COVID-19 in a young general population. The aim of the study is to investigate the prevalence and symptoms of post COVID-19 and its potential risk factors in young adults. Participants from the Swedish population-based birth cohort BAMSE were included (n = 2022, mean age 26.5 years). Post COVID-19 was assessed through a questionnaire and defined as symptoms after confirmed COVID-19 (registry-based or self-reported positive test) lasting for ≥ 2 months. In total, 681 participants had had confirmed COVID-19. Among them, 112 (16.5%) fulfilled the definition of post COVID-19 (17.8% in females, 14.5% in males, p = 0.26). The most common post COVID-19 symptoms were altered smell and taste (68.8%), dyspnea (33.7%) and fatigue (30.4%). Overall, no major risk factors for post COVID-19 were identified except for being bedbound during COVID-19. However, asthma and rhinitis were associated with the post COVID-19 symptom dyspnea, migraine with altered smell and taste, and lower self-rated health with fatigue. In conclusion, post COVID-19 symptoms are common, also among young adults in the general population. Although not life-threatening, it could have a considerable impact on public health due to the high prevalence and long-term symptoms.

Circulating CC16 and Asthma: A Population-based, Multicohort Study from Early Childhood through Adult Life.

Rationale: Club cell secretory protein (CC16) is an antiinflammatory protein highly expressed in the airways. CC16 deficiency has been associated with lung function deficits, but its role in asthma has not been established conclusively. Objectives: To determine 1) the longitudinal association of circulating CC16 with the presence of active asthma from early childhood through adult life and 2) whether CC16 in early childhood predicts the clinical course of childhood asthma into adult life. Methods: We assessed the association of circulating CC16 and asthma in three population-based birth cohorts: the Tucson Children's Respiratory Study (years 6-36; total participants, 814; total observations, 3,042), the Swedish Barn/Children, Allergy, Milieu, Stockholm, Epidemiological survey (years 8-24; total participants, 2,547; total observations, 3,438), and the UK Manchester Asthma and Allergy Study (years 5-18; total participants, 745; total observations, 1,626). Among 233 children who had asthma at the first survey in any of the cohorts, baseline CC16 was also tested for association with persistence of symptoms. Measurements and Main Results: After adjusting for covariates, CC16 deficits were associated with increased risk for the presence of asthma in all cohorts (meta-analyzed adjusted odds ratio per 1-SD CC16 decrease, 1.20; 95% confidence interval [CI], 1.12-1.28; P < 0.0001). The association was particularly strong for asthma with frequent symptoms (meta-analyzed adjusted relative risk ratio, 1.40; 95% CI, 1.24-1.57; P < 0.0001), was confirmed for both atopic and nonatopic asthma, and was independent of lung function impairment. After adjustment for known predictors of persistent asthma, children with asthma in the lowest CC16 tertile had a nearly fourfold increased risk for having frequent symptoms persisting into adult life compared with children with asthma in the other two CC16 tertiles (meta-analyzed adjusted odds ratio, 3.72; 95% CI, 1.78-7.76; P < 0.0001). Conclusions: Circulating CC16 deficits are associated with the presence of asthma with frequent symptoms from childhood through midadult life and predict the persistence of asthma symptoms into adulthood. These findings support a possible protective role of CC16 in asthma and its potential use for risk stratification.

Dietary fibre in relation to lung function and respiratory symptoms from childhood to adulthood.

Background: Epidemiological studies suggest beneficial associations between dietary fibre intake, lung function and chronic respiratory symptoms in adults. Our aim was to investigate the association between dietary fibre intake in childhood and respiratory health up to adulthood. Methods: The individual fibre intake of 1956 participants from the Swedish population-based birth cohort BAMSE was estimated from 98- and 107-item food frequency questionnaires at ages 8 and 16 years, respectively. At 8, 16 and 24 years, lung function was measured by spirometry. Respiratory symptoms (cough, mucus production, breathing difficulties/wheeze) were assessed by questionnaires, and airway inflammation by exhaled nitric oxide fraction (FENO) (≥25 ppb) at 24 years. Longitudinal associations with lung function were analysed by mixed-effects linear regression; associations with respiratory symptoms and airway inflammation were analysed by logistic regression, adjusting for potential confounders. Results: There were no associations between fibre intake at 8 years, as total and from different sources, spirometry measurements and respiratory symptoms at 24 years. Higher fruit fibre intake tended to be inversely associated with airway inflammation at 24 years (OR 0.70, 95% CI 0.48-1.00), which became non-significant after exclusion of participants with food-related allergic symptoms (OR 0.74, 95% CI 0.49-1.10). No associations between fibre intake at 8 and 16 years as an updated lagged exposure and spirometry measurements up to 24 years were observed. Conclusion: In this longitudinal study, we observed no consistent association between dietary fibre intake in childhood and lung function or respiratory symptoms up to adulthood. Further research on dietary fibre in relation to respiratory health across the life course is needed.

Associations of improved air quality with lung function growth from childhood to adulthood: the BAMSE study.

BACKGROUND: The beneficial effect of improving air quality on lung function development remains understudied. We assessed associations of changes in ambient air pollution levels with lung function growth from childhood until young adulthood in a Swedish cohort study. METHODS: In the prospective birth cohort BAMSE (Children, Allergy, Environment, Stockholm, Epidemiology (in Swedish)), spirometry was conducted at the 8-year (2002-2004), 16-year (2011-2013) and 24-year (2016-2019) follow-ups. Participants with spirometry data at 8 years and at least one other measurement in subsequent follow-ups were included (1509 participants with 3837 spirometry measurements). Ambient air pollution levels (particulate matter with diameter ≤2.5 µm (PM2.5), particulate matter with diameter ≤10 µm (PM10), black carbon (BC) and nitrogen oxides (NO x )) at residential addresses were estimated using dispersion modelling. Linear mixed effect models were used to estimate associations between air pollution exposure change and lung function development. RESULTS: Overall, air pollution levels decreased progressively during the study period. For example, the median (interquartile range (IQR)) level of PM2.5 decreased from 8.24 (0.92) µg·m-3 during 2002-2004 to 5.21 (0.67) µg·m-3 during 2016-2019. At the individual level, for each IQR reduction of PM2.5 the lung function growth rate increased by 4.63 (95% CI 1.64-7.61) mL per year (p<0.001) for forced expiratory volume in 1 s and 9.38 (95% CI 4.76-14.00) mL per year (p<0.001) for forced vital capacity. Similar associations were also observed for reductions of BC and NO x . Associations persisted after adjustment for potential confounders and were not modified by asthma, allergic sensitisation, overweight, early-life air pollution exposure or dietary antioxidant intake. CONCLUSIONS: Long-term reduction of air pollution is associated with positive lung function development from childhood to young adulthood.

Plasticity of Individual Lung Function States from Childhood to Adulthood.

Rationale: Recent evidence highlights the importance of optimal lung development during childhood for health throughout life. Objectives: To explore the plasticity of individual lung function states during childhood. Methods: Prebronchodilator FEV1 z-scores determined at age 8, 16, and 24 years in the Swedish population-based birth cohort BAMSE (Swedish abbreviation for Child [Barn], Allergy, Milieu, Stockholm, Epidemiological study) (N = 3,069) were used. An unbiased, data-driven dependent mixture model was applied to explore lung function states and individual state chains. Lung function catch-up was defined as participants moving from low or very low states to normal or high or very high states, and growth failure as moving from normal or high or very high states to low or very low states. At 24 years, we compared respiratory symptoms, small airway function (multiple-breath washout), and circulating inflammatory protein levels, by using proteomics, across states. Models were replicated in the independent Dutch population-based PIAMA (Prevention and Incidence of Asthma and Mite Allergy) cohort. Measurements and Main Results: Five lung function states were identified in BAMSE. Lung function catch-up and growth failure were observed in 74 (14.5%) BAMSE participants with low or very low states and 36 (2.4%) participants with normal or high or very high states, respectively. The occurrence of catch-up and growth failure was replicated in PIAMA. Early-life risk factors were cumulatively associated with the very low state, as well as with catch-up (inverse association) and growth failure. The very low state as well as growth failure were associated with respiratory symptoms, airflow limitation, and small airway dysfunction at adulthood. Proteomics identified IL-6 and CXCL10 (C-X-C motif chemokine 10) as potential biomarkers of impaired lung function development. Conclusions: Individual lung function states during childhood are plastic, including catch-up and growth failure.

Lung function in young adulthood: differences between males and females with asthma.

Background: There are phenotypic differences in asthma in males and females. Differences in lung function between the sexes at the peak lung function level in young adulthood are so far not directly addressed. The aim of the present study was to assess lung function in early adulthood in males and females depending on asthma onset and remission. Methods: Participants were included from the population-based birth cohort BAMSE and classified as having: never asthma, childhood asthma in remission, adolescent onset asthma or persistent asthma. Pre- and post-bronchodilator lung function (in Z-score) and lung clearance index (LCI) were measured at age 24 years. Lung function was compared stratified for sex between the never asthma and asthma groups univariately and in multiple linear regression analyses adjusted for maternal and paternal asthma, maternal smoking during pregnancy, secondary smoking, daily smoking, early respiratory syncytial virus infection, traffic pollution, childhood allergic sensitisation, and body mass index at age 24 years. Results: All asthma phenotypes were associated with a lower forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) post-bronchodilation at 24 years. This was most pronounced in males with persistent asthma compared to males with never asthma (regression coefficient: -0.503; 95% CI: -0.708- -0.298). Childhood asthma (in remission or persistent) was associated with a lower FEV1. After adjustment, the associations remained significant for males. For females, the significant associations with lower FEV1 and FEV1/FVC remained only for subjects with asthma in remission. Persistent asthma was associated with higher LCI in females. Conclusions: In females, in contrast to males, the association between asthma and lower lung function was attenuated after adjustment for known risk factors.

Air pollution exposure impairs lung function in infants.

AIM: To assess associations between air pollution exposure and infant lung function. METHODS: Healthy infants from Stockholm were recruited to two cohorts (n = 99 and n = 78). Infant spirometry included plethysmography and raised volume forced expiratory flows. In pooled analyses, lung function at ~6 months of age was related to time-weighted average air pollution levels at residential addresses from birth until the lung function test. The pollutants included particulate matter with an aerodynamic diameter < 10 µm (PM10 ) or <2.5 µm and nitrogen dioxide. RESULTS: There were significant inverse relations between air pollution exposure during infancy and forced expiratory volume at 0.5 s (FEV0.5 ) as well as forced vital capacity (FVC) for all pollutants. For example, the decline was 10.1 ml (95% confidence interval 1.3-18.8) and 10.3 ml (0.5-20.1) in FEV0.5 and FVC, respectively, for an interquartile increment of 5.3 µg/m3 in PM10 . Corresponding associations for minute ventilation and functional residual capacity were 43.3 ml/min (-9.75-96.3) and 0.84 ml (-4.14-5.82). CONCLUSIONS: Air pollution exposure was associated with impaired infant lung function measures related to airway calibre and lung volume, suggesting that comparatively low levels of air pollution negatively affect lung function in early life.

Dietary intake and plasma concentrations of PUFAs in childhood and adolescence in relation to asthma and lung function up to adulthood.

BACKGROUND: PUFAs may influence the risk of asthma; however, long-term prospective studies including objective biomarkers of PUFA intake are lacking. OBJECTIVES: The objective was to investigate the role of dietary intake and plasma concentrations of n-3 and n-6 (ω-3 and ω-6) PUFAs in childhood and adolescence for the development of asthma and lung function up to young adulthood. METHODS: The study included participants from the Swedish prospective birth cohort BAMSE. Dietary intake of PUFAs was calculated from FFQs (n = 1992) and plasma proportions of PUFAs were measured in phospholipids (n = 831). We analyzed the n-3 PUFA α-linolenic acid (ALA; 18:3n-3); the sum of very-long-chain (VLC) n-3 PUFAs: EPA (20:5n-3), DHA (22:6n-3), and docosapentaenoic acid (22:5n-3); and the n-6 PUFAs linoleic acid (LA; 18:2n-6) and arachidonic acid (AA; 20:4n-6). Asthma was assessed by questionnaires at 8, 16, and 24 y and lung function was measured by spirometry at 24 y. RESULTS: A high (≥median) self-reported dietary intake of LA at 8 y and AA at 16 y was associated with increased risk of prevalent asthma at 24 y (OR: 1.41; 95% CI: 1.10, 1.82 and OR: 1.32; 95% CI: 1.02, 1.70, respectively). In contrast, plasma proportions of ALA, ∑VLC n-3 PUFAs, and AA at 8 y, as well as LA at 16 y, were inversely associated with prevalent asthma at 24 y (e.g., OR: 0.55; 95% CI: 0.38, 0.81 for ∑VLC n-3 PUFAs). No consistent associations were observed with lung function. CONCLUSIONS: High dietary intake of certain n-6 PUFAs in childhood or adolescence may be associated with increased risk of asthma up to young adulthood, whereas dietary biomarkers of certain n-3 and n-6 PUFAs in plasma may be associated with decreased risk. Thus, the role of diet compared with altered metabolism of PUFAs needs further investigation to improve dietary preventive strategies for asthma.

The role of growth and nutrition in the early origins of spirometric restriction in adult life: a longitudinal, multicohort, population-based study.

BACKGROUND: Spirometric restriction, defined as a reduced forced vital capacity (FVC) with a preserved FEV1/FVC ratio, is associated with increased respiratory and non-respiratory comorbidities and all-cause mortality in adulthood. Little is known about the early origins of this condition. We sought to identify early-life risk factors for spirometric restriction in adult life. METHODS: In this longitudinal, multicohort, population-based study, we used data from the Tucson Children's Respiratory Study (TCRS), which recruited 1246 healthy infants at birth between April 1980, and October 1984, in Tucson, AZ, USA. Questionnaires were answered by the primary caregiver at enrolment, immediately after the child's birth, and multiple follow-up questionnaires were completed through childhood and adulthood. At the age of 22, 26, 32, and 36 years, lung function was measured with spirometry. At each survey, three mutually exclusive spirometric patterns were defined: (1) normal (FEV1/FVC ≥10th percentile and FVC ≥10th percentile); (2) restrictive (FEV1/FVC ≥10th percentile and FVC <10th percentile); and (3) obstructive (FEV1/FVC <10th percentile, independent of FVC). Data on demographic features and parental health factors were collected from questionnaires; pregnancy and perinatal data (including nutritional problems) and birth measurements were obtained from medical records; and weight, height, and body-mass index (BMI) during childhood (age 6-16 years) were measured by study nurses. The associations between early-life risk factors and spirometric patterns were assessed by multivariate multinomial logistic regression analysis, adjusted for survey year, sex, and race-ethnicity. Significant risk factors were further tested for replication in the Swedish Child (Barn), Allergy, Milieu, Stockholm, Epidemiological (BAMSE; n=1817; spirometry surveys were done at age 24 years) survey and the UK Manchester Asthma and Allergy Study (MAAS; n=411; spirometry surveys were done at age 18 years) birth cohorts, and fixed-effect meta-analyses of relative risk ratios (RRRs) from multinomial logistic regression models were done to generate a pooled estimate of the effect across the three cohorts. Measurements of body composition (MAAS; n=365) and total lung capacity (TCRS; n=173 and MAAS; n=407) were also available for a subset of participants. FINDINGS: Of 1246 healthy infants included in TCRS, for the present study we included data for 652 participants who had at least one set of spirometry data, contributing up to 1668 observations. In the TCRS cohort, results from the multivariate models showed that maternal nutritional problems during pregnancy (RRR 2·48 [95% CI 1·30-4·76]; p=0·0062), being born small for gestational age (birthweight <10th percentile; 3·26 [1·34-7·93]; p=0·0093), and being underweight in childhood (BMI-for-age <5th percentile; 3·54 [1·35-9·26]; p=0·010) were independent predictors of spirometric restriction in adult life. Associations between being small for gestational age (p=0·0028) and underweight in childhood (p<0·0001) with adult spirometric restriction were supported by the results of meta-analysis of data from all three cohorts. In the MAAS cohort, having a low lean BMI (ie, <10th percentile) at age 11 years predicted adult (age 18 years) spirometric restriction (RRR 3·66 [1·48-9·02]; p=0·0048). These associations of spirometric restriction with small for gestational age, childhood underweight, and low lean BMI in childhood were verified in participants with spirometric restriction who had diminished total lung capacity, indicating that these factors specifically increase the risk of lung restriction. INTERPRETATION: Poor growth and nutritional deficits in utero and throughout childhood precede and predict the development of spirometric restriction in adult life. Strategies to improve prenatal and childhood growth trajectories could help to prevent spirometric restriction and its associated morbidity and mortality burden. FUNDING: National Institutes of Health.

Fruit, vegetable and dietary antioxidant intake in school age, respiratory health up to young adulthood.

BACKGROUND: Dietary antioxidants may protect the lung against oxidative damage and prevent chronic respiratory disease. We aimed to investigate fruit, vegetable and antioxidant intake (measured as total antioxidant capacity, TAC) at age 8 years in relation to asthma and lung function up to 24 years. METHODS: In this study of 2506 participants from a Swedish birth cohort, diet was assessed using food frequency questionnaires. Information on asthma was collected by questionnaires, and lung function was measured by spirometry at ages 8, 16 and 24 years. Generalized estimating equations and mixed effect models were used to assess overall, age- and sex-specific associations. RESULTS: After adjustment for confounders, a higher fruit intake at age 8 years was associated with a tendency to reduced odds of prevalent asthma (T3 vs. T1, OR 0.78; 95% CI 0.60-1.01, p-trend .083), with reduced odds of incident asthma and increased odds of remittent asthma (≥median, OR 0.76; 95% CI 0.58-0.99 and OR 1.60; 95% CI 1.05-2.42, respectively) up to 24 years. Comparable, but non-significant, odds ratios were observed in analyses of long-term fruit intake (mean intake at ages 8 and 16 years). In contrast, no association was observed with vegetable intake. A higher dietary TAC (T3 vs. T1) at 8 years was associated with reduced odds of prevalent asthma (OR 0.73; 95% CI 0.58-0.93, p-trend .010) and improved lung function development (FEV1 -z +0.11; 95% CI 0.01-0.21, p-trend .036 and FVC-z +0.09; 95% CI -0.01-0.20, p-trend .072) up to 24 years. Associations were more pronounced among males, and regarding asthma, participants sensitized to aeroallergens. CONCLUSIONS: Antioxidant intake in school age may improve asthma and lung function up to young adulthood. Although our results should be interpreted with caution, they emphasize the importance of following current dietary guidelines regarding consumption of antioxidant-rich foods as part of a balanced diet.

Lung function before and after COVID-19 in young adults: A population-based study.

Background: There is limited evidence on the long-term impact of mild-to-moderate coronavirus disease 2019 (COVID-19) on lung function among young adults. Objectives: We aimed to assess whether COVID-19 has a negative impact on lung function in young adults and whether asthma, allergic sensitization, or use of inhaled corticosteroids (ICSs) modifies a potential association. Methods: Participants from the population-based BAMSE (Barn, Allergi, Miljö, Stockholm, Epidemiologi) cohort with spirometry assessed before (2016-2019) and after onset of the COVID-19 pandemic (2020-2021) were included. Serum levels of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) receptor-binding domain-specific IgG, IgM, and/or IgA (determined with ELISA) defined seropositivity. Mean change in lung function (ie, change in FEV1, forced vital capacity [FVC], and FEV1/FVC ratio expressed as percent of predicted [pp]) from before to after onset of the pandemic were compared between the seronegative and seropositive participants. In seropositive participants, change in lung function was assessed in relation to allergic sensitization and self-reported ICS use. Results: Of the 853 included participants, 29% (n = 243) were seropositive. There were no differences in change in lung function between the seronegative and seropositive participants (for mean change in FEV1 pp [SD], seropositivity = 0.87% [4.79%] and seronegativity = 1.03% (4.76%) [P = .66] for difference using a t test; FVC pp (SD), seropositivity = 1.34% (4.44%) and seronegativity = 1.29% (4.27%) [P = .87]; and for FEV1/FVC pp (SD), seropositivity = -0.25% (3.13%) and seronegativity = -0.13% (3.15%) [P = .61]). Similar results were observed among participants with asthma (n = 147 [17%]). Among seropositive participants, allergic sensitization or ICS use did not influence lung function. Conclusion: We found no evidence of mild-to-moderate COVID-19 affecting lung function long term in a population-based cohort of young adults. Moreover, neither asthma nor allergic sensitization nor ICS use affected the results.

Spirometric phenotypes from early childhood to young adulthood: a Chronic Airway Disease Early Stratification study.

BACKGROUND: The prevalences of obstructive and restrictive spirometric phenotypes, and their relation to early-life risk factors from childhood to young adulthood remain poorly understood. The aim was to explore these phenotypes and associations with well-known respiratory risk factors across ages and populations in European cohorts. METHODS: We studied 49 334 participants from 14 population-based cohorts in different age groups (≤10, >10-15, >15-20, >20-25 years, and overall, 5-25 years). The obstructive phenotype was defined as forced expiratory volume in 1 s (FEV1)/forced vital capacity (FVC) z-score less than the lower limit of normal (LLN), whereas the restrictive phenotype was defined as FEV1/FVC z-score ≥LLN, and FVC z-score

Uncontrolled asthma from childhood to young adulthood associates with airflow obstruction.

INTRODUCTION: Lung function development from childhood to young adulthood is important for lung health later in life. We investigated the association between asthma control and lung function from 8 to 24 years of age. METHODS: A total of 668 participants from the population-based BAMSE cohort study, with persistent or incidental asthma and between 8 and 24 years of age, were included. Asthma was defined as controlled or uncontrolled at each examination based on the Global Initiative for Asthma (GINA) criteria. Dynamic spirometry was performed at 8, 16 and 24 years of age. Associations between uncontrolled asthma and pre-bronchodilation forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and FEV1/FVC ratio were evaluated with a generalised estimating equation model, as overall associations and at each examination. Unadjusted and adjusted (for sex, current asthma, allergic sensitisation, body mass index, smoking, smoke exposure, inhaled corticosteroid use) analyses were done; and were thereafter stratified by sex, elevated blood eosinophils (≥0.3×109 cells·µL-1), elevated F ENO (≥25 ppb), allergic sensitisation and ever/never smoking. RESULTS: Uncontrolled asthma was associated with a lower overall FEV1/FVC z-score from 8 to 24 years of age (adjusted regression coefficient -0.11; 95% CI (-0.20 to -0.02; p=0.016). After stratification, this association was primarily seen among females (adjusted regression coefficient -0.170; 95% CI (-0.298 to -0.044; p=0.009) and participants with elevated F ENO (regression coefficient -0.207; 95% CI -0.342 to -0.073; p=0.002), in contrast to males and participants with normal F ENO. CONCLUSION: Uncontrolled asthma is associated with airflow obstruction from childhood to young adulthood. This highlights the importance of active management of asthma during growth.