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Background and Objective: Chronic, low‐intensity air pollution exposure has been consistently associated with reduced lung function throughout childhood. However, there is limited research regarding the implications of acute, high‐intensity air pollution exposure. We aimed to determine whether there were any associations between early life exposure to such an episode and lung growth trajectories. Methods: We conducted a prospective cohort study of children who lived in the vicinity of the Hazelwood coalmine fire. Lung function was measured using respiratory oscillometry. Z‐scores were calculated for resistance (R5) and reactance at 5 Hz (X5) and area under the reactance curve (AX). Two sets of analyses were conducted: (i) linear regression to assess the cross‐sectional relationship between post‐natal exposure to mine fire‐related particulate matter with an aerodynamic diameter of less than 2.5 micrometres (PM2.5) and lung function at the 7‐year follow‐up and (ii) linear mixed‐effects models to determine whether there was any association between exposure and changes in lung function between the 3‐ and 7‐year follow‐ups. Results: There were no associations between mine fire‐related PM2.5 and any of the lung function measures, 7‐years later. There were moderate improvements in X5 (β: −0.37 [−0.64, −0.10] p = 0.009) and AX (β: −0.40 [−0.72, −0.08] p = 0.014), between the 3‐ and 7‐year follow‐ups that were associated with mean PM2.5, in the unadjusted and covariance‐adjusted models. Similar trends were observed with maximum PM2.5. Conclusion: There was a moderate improvement in lung stiffness of children exposed to PM2.5 from a local coalmine fire in infancy, consistent with an early deficit in lung function at 3‐years after the fire that had resolved by 7‐years. [ABSTRACT FROM AUTHOR]

Background and Objective: Despite the high burden of respiratory disease amongst Indigenous populations, prevalence data on spirometric deficits and its determinants are limited. We estimated the prevalence of abnormal spirometry in young Indigenous adults and determined its relationship with perinatal and early life factors. Methods: We used prospectively collected data from the Australian Aboriginal Birth Cohort, a birth cohort of 686 Indigenous Australian singletons. We calculated the proportion with abnormal spirometry (z‐score <−1.64) and FEV1 below the population mean (FEV1% predicted 0 to −2SD) measured in young adulthood. We evaluated the association between perinatal and early life exposures with spirometry indices using linear regression. Results: Fifty‐nine people (39.9%, 95%CI 31.9, 48.2) had abnormal spirometry; 72 (49.3%, 95%CI 40.9, 57.7) had a FEV1 below the population mean. Pre‐school hospitalisations for respiratory infections, younger maternal age, being overweight in early childhood and being born remotely were associated with reduced FEV1 and FVC (absolute, %predicted and z‐score). The association between maternal age and FEV1 and FVC were stronger in women, as was hospitalization for respiratory infections before age 5. Being born remotely had a stronger association with reduced FEV1 and FVC in men. Participants born in a remote community were over 6 times more likely to have a FEV1 below the population mean (odds ratio [OR] 6.30, 95%CI 1.93, 20.59). Conclusion: Young Indigenous adults have a high prevalence of impaired lung function associated with several perinatal and early life factors, some of which are modifiable with feasible interventions. [ABSTRACT FROM AUTHOR]

Background: The extent to which biomarkers of asthma activity persist in spontaneous asthma remission and whether such markers are associated with future respiratory outcomes remained unclear. We investigated the association between sub‐clinical inflammation in adults with spontaneous asthma remission and future asthma relapse and lung function decline. Methods: The Tasmanian Longitudinal Health Study is a population‐based cohort (n = 8583). Biomarkers of systemic inflammation were measured on participants at age 45, and latent profile analysis was used to identify cytokine profiles. Bronchial hyperresponsiveness (BHR) and nitric oxide products in exhaled breath condensate (EBC NOx) were measured at age 50. Participants with spontaneous asthma remission at ages 45 (n = 466) and 50 (n = 318) were re‐evaluated at age 53, and associations between baseline inflammatory biomarkers and subsequent asthma relapse and lung function decline were assessed. Results: We identified three cytokine profiles in adults with spontaneous asthma remission: average (34%), Th2‐high (42%) and Th2‐low (24%). Compared to the average profile, a Th2‐high profile was associated with accelerated decline in post‐BD FEV1/FVC (MD −0.18% predicted per‐year; 95% CI −0.33, −0.02), while a Th2‐low profile was associated with accelerated decline in both post‐BD FEV1 (−0.41%; −0.75, −0.06) and post‐BD FVC (−0.31%; −0.62, 0.01). BHR and high TNF‐α during spontaneous remission were associated with an increased risk of asthma relapse. In contrast, we found no evidence of association between EBC NOx and either asthma relapse or lung function decline. Conclusion: BHR and serum inflammatory cytokines have prognostic value in adults with spontaneous asthma remission. At‐risk individuals with BHR, Th2‐high or Th2‐low cytokine profiles may benefit from closer monitoring and on‐going follow‐up. [ABSTRACT FROM AUTHOR]

Background and objective: The link between respiratory and vascular health is well documented in adult populations. Impaired lung function is consistently associated with thicker arteries and higher incidence of cardiovascular disease. However, there are limited data on this relationship in young children and the studies that exist have focussed on populations at high risk of cardiorespiratory morbidity. We determined if an association exists between respiratory and cardiovascular function in young children and, if so, whether it is confounded by known cardiorespiratory risk factors. Methods: Respiratory and vascular data from a prospective cohort study established to evaluate the health implications 3 years after coal mine fire smoke exposure in children aged 3–5 years were used. Respiratory function was measured using the forced oscillation technique and included resistance at 5 Hz (R5), reactance at 5 Hz (X5) and area under the reactance curve (AX). Vascular health was measured by carotid intima‐media thickness (ultrasound) and pulse wave velocity (arterial tonometry). Regression analyses were used to examine the relationship between the respiratory Z‐scores and cardiovascular measures. Subsequent analyses were adjusted for potential confounding by maternal smoking during pregnancy, maternal education and exposure to fine particulate matter <2.5 μm in aerodynamic diameter (PM2.5). Results: Peripheral lung function (X5 and AX), but not respiratory system resistance (R5), was associated with vascular function. Adjustment for maternal smoking, maternal education and early life exposure to PM2.5 had minimal effect on these associations. Conclusion: These observations suggest that peripheral lung stiffness is associated with vascular stiffness and that this relationship is established early in life. [ABSTRACT FROM AUTHOR]

Despite the growing body of evidence on lung function trajectories over the life course and their risk factors, the literature has not been systematically synthesized. Publications related to lung function trajectories were identified from PubMed, EMBASE and CINAHL databases. Two authors independently identified publications for inclusion according to predefined selection criteria. Studies that modelled lung function trajectories and reported associated exposures were included. Meta-analyses could not be conducted due to heterogeneity in the exposures and methods used to model lung function trajectories. Nine publications were eligible for inclusion of which four used group-based trajectory modelling to model lung function trajectories, while five used latent profile analysis. Studies with repeated lung function measurements over the life course identified more trajectories than others. Only one study spanning from childhood to middle age reported catch-up trajectory. The following childhood risk factors for subnormal lung function trajectories were observed in at least across two studies: low birth weight, early wheezing, asthma, allergic sensitization, eczema, allergic rhinitis, lower respiratory tract infections, family history of asthma and second-hand smoke exposure. Adult active asthma and personal cigarette smoking were observed to be associated with accelerated decline lung trajectories. Our review identified 10 risk factors associated with the growth, catch-up, reduced plateau and decline trajectories of lung function. Intervention directed at childhood asthma and infections, and tobacco smoke exposure at all ages would help promote lung health and prevent subnormal lung function trajectories. [ABSTRACT FROM AUTHOR]

Background: Experimental challenge studies have shown that pollen can have early and delayed effects on the lungs and airways. Here, we qualitatively and quantitatively synthesize the evidence of outdoor pollen exposure on various lung function and airway inflammation markers in community‐based studies. Methods: Four online databases were searched: Medline, Web of Science, CINAHL and Google Scholar. The search strategy included terms relating to both exposure and outcomes. Inclusion criteria were human‐based studies published in English that were representative of the community. Additionally, we only considered cross‐sectional or short‐term longitudinal studies which investigated pollen exposure by levels or season. Study quality assessment was performed using the Newcastle‐Ottawa scale. Meta‐analysis was conducted using random‐effects models. Results: We included 27 of 6551 studies identified from the search. Qualitative synthesis indicated associations between pollen exposure and predominantly type‐2 inflammation in both the upper and lower airways, but little evidence for lung function changes. People with ever asthma and/or seasonal allergic rhinitis (SAR) were at higher risk of such airway inflammation. Meta‐analysis confirmed a positive relationship between pollen season, eosinophilia and eosinophil cationic protein (ECP) in people with ever SAR but the results between studies were highly variable. Heterogeneity was reduced after further subgrouping by age, and the forest plots indicated that eosinophilic airway inflammation to outdoor pollen exposure increased with age. Conclusion: Among people with ever asthma and ever SAR, exposure to increased ambient pollen triggers type‐2 upper and lower airway inflammation rather than a non‐specific or innate inflammation. These findings can lead to the formulation of specific pollen immunotherapy for susceptible individuals. Future research should be directed towards investigating lagged associations and effect modifications using larger and more generalized populations. Systematic review registration: CRD42020146981 (PROSPERO). [ABSTRACT FROM AUTHOR]

Background: The association between grass pollen exposure and early markers of asthma exacerbations such as lung function changes and increase in airway inflammation is limited. We investigated the associations between short‐term grass pollen exposure and lung function and airway inflammation in a community‐based sample, and whether any such associations were modified by current asthma, current hay fever, pollen sensitization, age, and other environmental factors. Methods: Cross‐sectional and short‐term analyses of data from the Melbourne Atopy Cohort Study (MACS) participants (n = 936). Lung function was assessed using spirometry. Airway inflammation was assessed by fractional exhaled nitric oxide (FeNO) and exhaled breath condensate pH and nitrogen oxides (NOx). Daily pollen counts were collected using a volumetric spore trap. The associations were examined by linear regression. Results: Higher ambient levels of grass pollen 2 days before (lag 2) were associated with lower mid‐forced expiratory flow (FEF25%‐75%) and FEV1/FVC ratio (Coef. [95% CI] = −119 [−226, −11] mL/s and −1.0 [−3.0, −0.03] %, respectively) and also 3 days before (lag 3). Increased levels of grass pollen a day before (lag 1) were associated with increased FeNO (4.35 [−0.1, 8.7] ppb) and also at lag 2. Adverse associations between pollen and multiple outcomes were greater in adults with current asthma, hay fever, and pollen sensitization. Conclusion: Grass pollen exposure was associated with eosinophilic airway inflammation 1‐2 days after exposure and airway obstruction 2‐3 days after exposure. Adults and individuals with asthma, hay fever, and pollen sensitization may be at higher risk. [ABSTRACT FROM AUTHOR]

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Background: Physical activity may be a potentially modifiable risk factor for asthma and driver of lung function development. This systematic review aimed to summarize the available evidence concerning the longitudinal effect of physical activity on the development of asthma, the persistence of asthma symptoms and lung function outcomes in children and adolescents. Methods: PubMed and Embase electronic databases were searched for all original articles that investigated the longitudinal association between physical activity and asthma outcomes or lung function outcomes in children and adolescents. The search and data extraction were conducted by two independent researchers. The methodological quality of the included studies was assessed using two critical assessment tools. Results: The literature search retrieved 2298 publications from the electronic databases. All articles were screened, and 2289 were subsequently excluded, resulting in nine longitudinal studies eligible for inclusion in this review. Two studies found no association with incident wheeze, and two of four found no association with various asthma outcomes. Three studies investigated the effect on lung function: one observed an association in boys only, one observed an association in girls only, and one found no associations. Conclusion: The evidence was highly inconsistent for the relationship between physical activity and asthma and lung function outcomes. Hence, we conclude that there is insufficient evidence to suggest that physical activity has a long‐term effect on the risk of asthma development in youth. Furthermore, there is insufficient evidence to determine the longitudinal effects of physical activity on lung function in children. [ABSTRACT FROM AUTHOR]

Background: Exposure to high levels of pollen in infancy is a risk factor for allergic respiratory diseases in later childhood, but effects on lung function are not fully understood. We aim to examine associations between grass pollen exposure in the first months of life and lung function at 12 and 18 years, and explore potential modification. Methods: Using the Melbourne Atopy Cohort Study, a birth cohort of children with a family history of allergic diseases, we modeled the association between cumulative grass pollen exposure up to 3 months after birth, on FEV1, FVC, and FEV1/FVC ratio at 12 and 18 years. We also assessed modifying effects of residential greenness levels (derived from satellite imagery), asthma, and early life sensitization to ryegrass. Results: Grass pollen exposure in the first 7 days was associated with a reduction in FEV1 (−15.5 mL; 95% CI: −27.6, −3.3 per doubling of pollen count) and FVC (−20.8 mL; −35.4, −6.1) at 12 years, but not at 18 years. Increase in cumulative grass pollen exposure up to 3 months was negatively associated with FVC at 12 and 18. Exposure to high residential greenness modified the association at 18 years. Conclusion: Early exposure to grass pollen was associated with decreased lung function in children and adolescents. Targeted interventions for pollen avoidance strategies that take into account local topography could be implemented alongside other clinical interventions such as immunotherapy. [ABSTRACT FROM AUTHOR]