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Introduction: Evidence on the early life risk factors of adult CRS, and the history of asthma and allergies across the life course, is limited., Aim: To investigate relationships between respiratory infective/allergic conditions in childhood, and asthma and allergies across the life course and CRS in middle age., Methods: Data were from the population-based Tasmanian Longitudinal Health Study (TAHS) cohort, first studied in 1968 when aged 6-7 years (n = 8583) and serially followed into middle age (n = 3609). Using a well-accepted epidemiological definition, participants were assigned a CRS-severity subtype at age 53: no sinusitis/CRS (reference); past doctor diagnosis only; current symptoms without doctor diagnosis; and doctor-diagnosed CRS with current symptoms. Relationships with infective/allergic respiratory illnesses at age 7, and previously published asthma-allergy trajectories from 7 to 53 years, were examined using multinominal regression., Results: In middle age, 5.8% reported current CRS symptoms with 2.5% doctor-diagnosed. Childhood conditions associated with symptomatic doctor-diagnosed CRS included frequent head colds (multinomial odds ratio [mOR] = 2.04 (95% confidence interval [95% CI]: 1.24, 3.37)), frequent tonsillitis (mOR = 1.61 [95% CI: 1.00, 2.59]) and current childhood asthma (mOR = 2.23 [95% CI: 1.25, 3.98]). Life course trajectories that featured late-onset or persistent asthma and allergies were associated with all CRS subtypes in middle age; early-onset persistent asthma and allergies (mOR = 6.74, 95% CI: 2.76, 16.4); late-onset asthma allergies (mOR = 15.9, 95% CI: 8.06, 31.4), and late-onset hayfever (mOR = 3.02, 95% CI: 1.51, 6.06) were associated with symptomatic doctor-diagnosed CRS., Conclusion: Current asthma, frequent head colds and tonsillitis at age 7 could signal a susceptible child who is at higher risk for CRS in mid-adult life and who might benefit from closer monitoring and/or proactive management. Concurrent asthma and allergies were strongly associated and are potential treatable traits of adult CRS., (© 2024 The Author(s). Allergy published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: Studies exploring early life-course BMI trajectories and subsequent mental health outcomes are limited but may provide important insights for early intervention. We investigated associations between BMI trajectories from 0 to 18 years and mental health outcomes in emerging adulthood., Methods: Data were obtained from 434 participants in the Melbourne Atopy Cohort Study (MACS). Anthropometric data were collected across 26 timepoints from infancy to age 25 and group-based trajectory modelling was used to develop BMI trajectories from 0.1 to 18 years. Moderate-to-severe psychological distress (MSPD) and likely depression were assessed at age 18 and 25 years. Associations between BMI trajectories and mental health at 25 years and change in mental health between 18 and 25 years were estimated using logistic regression. History of asthma, hay fever or eczema were independently examined as potential effect modifiers., Results: Five BMI trajectories were identified from 1 month to 18 years. When compared to the stable average BMI trajectory, we found an increased risk of MSPD (OR = 2.97; 95%CI: 1.09,8.06) and likely depression (3.56; 1.39,9.12) at age 25 in the average increasing-to-high trajectory. This group also had a greater likelihood of new-onset depression (4.82; 1.54,15.0) from 18 to 25 years of age., Limitations: MACS participants are not representative of the general population and mental health data was not available before 18 years of age., Conclusion: Excessive weight gain across the childhood transition was associated with poorer mental health in emerging adulthood, highlighting the importance of monitoring growth to allow for early identification and stratification of individuals at risk of poor mental health., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier B.V.)

There is growing interest in the epidemiology of asthma in developing countries, especially in the Asia-Pacific Region (APR). A number of reviews have been published in this field, but a comprehensive synthesis of overall data has not been reported. Here, we summarized the burden, risk factors and challenges of asthma management in developing countries with a specific emphasis on the APR by consolidating evidence from both systematic and narrative reviews published up until February 2023. We found that although asthma prevalence in low and low-middle-income countries (LMICs) is known to be generally lower compared to high-income countries, the burden is substantially greater. Studies conducted in APR LMIC have reported a range of risk factors, including pre- and post-natal factors, environmental considerations, lifestyle measures, individual features and genetics. The low and inequitable distribution of quality preventive and curative health care, a lack of advanced diagnostic measures, non-availability and non-affordability of novel therapeutics, cultural beliefs and practices, and diverse disease phenotypes make it challenging to achieve optimal asthma control in the region. Hence, we call for the development of a region-specific blueprint for action to mitigate this challenging situation, to help reduce the burden of asthma in APR LMIC., (© 2023 The Authors. Respirology published by John Wiley & Sons Australia, Ltd on behalf of Asian Pacific Society of Respirology.)

Background: Food allergy is considered a precursor to asthma in the context of the atopic march, but the relationship between infant food allergy phenotypes and lung function and asthma in childhood is unclear. We aimed to examine the association between food sensitisation and challenge-confirmed food allergy in infancy, as well as persistent and resolved food allergy up to age 6 years, and the risk of lung function deficits and asthma at age 6 years., Methods: The longitudinal, population-based HealthNuts cohort study in Melbourne, VIC, Australia, recruited 5276 infants children aged 1 year who attended council-run immunisation sessions between Sept 28, 2007, and Aug 5, 2011. At age 1 year, all children completed skin prick testing to four food allergens (egg, peanut, sesame, and either shrimp or cow's milk) and an oral food challenge (egg, peanut, and sesame) at the Royal Children's Hospital in Melbourne. Parents completed questionnaires about their infant's allergy history, demographic characteristics, and environmental exposures. At age 6 years, children were invited for a health assessment that included skin prick testing for ten foods (milk, egg, peanut, wheat, sesame, soy, shrimp, cashew, almond, and hazelnut) and eight aeroallergens (alternaria, cladasporum, house dust mite, cat hair, dog hair, bermuda grass, rye grass, and birch mix), oral food challenges, and lung function testing by spirometry. Questionnaires completed by parents (different to those completed at age 1 year) captured the child's allergy and respiratory history and demographics. We investigated associations between food allergy phenotypes (food-sensitised tolerance or food allergy; and ever, transient, persistent, or late-onset food allergy), lung function spirometry measures (forced expiratory volume in 1 sec [FEV 1 ] and forced vital capacity [FVC] z-scores, FEV 1 /FVC ratio, forced expiratory flow at 25% and 75% of the pulmonary volume [FEF 25-75% ], and bronchodilator responsiveness), and asthma using regression methods. Only children with complete data on the exposure, outcome, and confounders were included in models. Infants without food sensitisation or food allergy at age 1 year and 6 years served as the reference group., Findings: Of 5276 participants, 3233 completed the health assessment at age 6 years and were included in this analysis. Food allergy, but not food-sensitised tolerance, at age 1 year was associated with reduced FEV 1 and FVC (aβ -0·19 [95% CI -0·32 to -0·06] and -0·17 [-0·31 to -0·04], respectively) at age 6 years. Transient egg allergy was associated with reduced FEV 1 and FVC compared with never having egg allergy (-0·18 [95% CI -0·33 to -0·03] and -0·15 [-0·31 to 0·00], respectively), whereas persistent egg allergy was not (FEV 1 -0·09 [-0·48 to 0·31]; FVC -0·20 [-0·62 to 0·21]). Transient peanut allergy was associated with reduced FEV 1 and FVC (FEV 1 aβ -0·37 [-0·79 to 0·04] and FVC aβ -0·55 [-0·98 to -0·12]), in addition to persistent peanut allergy (FEV 1 aβ -0·30 [-0·54 to -0·06] and FVC aβ-0·30 [-0·55 to -0·05]), and late-onset peanut allergy (FEV 1 aβ -0·62 [-1·06 to -0·18] and FVC aβ-0·49 [-0·96 to -0·03]). Estimates suggested that food-sensitised tolerance and food allergy were associated with reduced FEF 25-75% , although some estimates were imprecise. Food allergy phenotypes were not associated with an FEV 1 /FVC ratio. Late-onset peanut allergy was the only allergy phenotype that was possibly associated with increased risk of bronchodilator responsiveness (2·95 [95% CI 0·77 to 11·38]). 430 (13·7%) of 3135 children were diagnosed with asthma before age 6 years (95% CI 12·5-15·0). Both food-sensitised tolerance and food allergy at age 1 year were associated with increased asthma risk at age 6 years (adjusted odds ratio 1·97 [95% CI 1·23 to 3·15] and 3·69 [2·81 to 4·85], respectively). Persistent and late-onset peanut allergy were associated with higher asthma risk (3·87 [2·39 to 6·26] and 5·06 [2·15 to 11·90], respectively)., Interpretation: Food allergy in infancy, whether it resolves or not, is associated with lung function deficits and asthma at age 6 years. Follow-up studies of interventions to prevent food allergy present an opportunity to examine whether preventing these food allergies improves respiratory health., Funding: National Health & Medical Research Council of Australia, Ilhan Food Allergy Foundation, AnaphylaxiStop, the Charles and Sylvia Viertel Medical Research Foundation, the Victorian Government's Operational Infrastructure Support Program., Competing Interests: Declaration of interests MLKT has received research funding from Prota Therapeutics, is an employee of Prota Therapeutics, has received consultancy fees from Pfizer, and is an inventor on patents owned by MCRI “A method for of inducing tolerance to an allergen” and “Allergy Treatment”. KPP is Chair of the scientific advisory board for AllergyPal; has received research grants from DBV Technologies, Novartis, Aravax, and Siolta; and consultant fees from Aravax, outside of the submitted work, paid to their institution. SCD, CJL, and AJL received investigator-initiated grants from GSK for unrelated work. AJL, SCD, and JJK have received grant funding from Sanofi Regeneron for unrelated research. AJL has received in kind contributions of study intervention (EpiCeram) from Primus Pharmaceuticals for unrelated research. RLP receives honoraria for editorial involvement with the journal Paediatric Allergy and Immunology. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background/objectives: Food hypersensitivity (FHS) is common, but little is known about the factors associated with severe reactions, age of onset and whether sensitization persists. This study examines the factors associated with self-reported severe food reactions, onset age and the changes in prevalence of sensitization to foods over time in an adult sample., Subjects/methods: We used data from adults taking part in the European Community Respiratory Health Survey (ECRHS) III (2010-2014) who provided information on food hypersensitivity, including symptoms, suspected culprit food and onset age (n = 4865). A subsample from six countries had serum food-specific IgE tested for 25 core foods and also in 10 years earlier (ECRHS II). We applied logistic regression and McNemar's test for analyses., Results: The prevalence of self-reported FHS was 13.5% at ECRHS III. Of those providing information on symptoms (n = 611), 26.4% reported severe reactions. About 80% of 1033 reported food-specific reactions (reported by 596 participants) began after age 15. History of asthma (odds ratio OR 2.12 95% confidence interval CI 1.13-3.44) and a younger age of onset of FHS (OR 1.02, 95% CI 1.01-1.03, per year) were associated with higher risks of a lifetime experience of severe food reactions. In the subsample with IgE tested in both surveys (n = 1612), the overall prevalence of sensitization to foods did not change over 10 years., Conclusion: Our findings support previous observations of more severe food reactions in people with asthma and that most FHS reported by this sample started after age 15. We found no evidence of changes in the prevalence of sensitization to food in adults followed for 10 years., (© 2023. The Author(s).)

There is current interest in the role of ambient pollen in the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2 or COVID-19) infection risk. The aim of this review is to summarise studies published up until January 2023 investigating the relationship between airborne pollen and the risk of COVID-19 infection. We found conflicting evidence, with some studies showing that pollen may increase the risk of COVID-19 infection by acting as a carrier, while others showed that pollen may reduce the risk by acting as an inhibiting factor. A few studies reported no evidence of an association between pollen and the risk of infection. A major limiting factor of this research is not being able to determine whether pollen contributed to the susceptibility to infection or just the expression of symptoms. Hence, more research is needed to better understand this highly complex relationship. Future investigations should consider individual and sociodemographic factors as potential effect modifiers when investigating these associations. This knowledge will help to identify targeted interventions.

Background: Despite chronic obstructive pulmonary disease (COPD) being a major global cause of mortality and hospitalisation, it is often undiagnosed or inaccurately diagnosed in clinical settings., Objective: To systematically synthesise all peer-reviewed papers from primary healthcare settings that have reported data on: (1) undiagnosed COPD, that is, patients with respiratory symptoms and postbronchodilator airflow obstruction consistent with COPD, without a formal clinician's diagnosis of COPD either documented in health records or reported by patients and (2) 'overdiagnosed COPD', that is, clinician's diagnosis without postbronchodilator airflow obstruction., Methods: Studies investigating these diagnostic metrics in patients from primary healthcare clinics (according to predefined inclusion/exclusion criteria) were sourced from Medline and Embase and assessed for bias (Johanna Briggs Institute tools for prevalence studies and case series). Meta-analyses of studies of adequate sample size used random effect modelling stratified by risk factor categories., Results: Of 26 eligible articles, 21 cross-sectional studies investigated 3959 cases of spirometry-defined COPD (with or without symptoms), and 5 peer-reviewed COPD case series investigated 7381 patients. The prevalence of spirometry-confirmed COPD without a diagnosis documented in their health records was 14%-26% in studies of symptomatic smokers (N=3). 1 in 4 patients taking inhaled therapies (25% (95% CI 22% to 28%), N=2) and 1 in 6 smokers irrespective of symptoms (16% (95% CI 14% to 18%), N=6) fulfilled diagnostic spirometry criteria but did not report receiving a COPD-related diagnosis. In an adequately powered series of COPD cases documented in primary healthcare records (N=4), only between 50% and 75% of subjects had any airflow obstruction on postbronchodilator spirometry performed by study researchers, therefore, COPD was clinically 'overdiagnosed' in 25%-50% of subjects., Discussion: Although data were heterogeneous and of modest quality, undiagnosed COPD was common in primary healthcare, especially for symptomatic smokers and patients treated with inhaled therapies. In contrast, frequent COPD 'overdiagnosis' may represent treatment of asthma/reversible component or another medical diagnosis., Prospero Registration Number: CRD42022295832., Competing Interests: Competing interests: JP, SCD, EHW and MJA hold an investigator-initiated grant from GlaxoSmithKline for unrelated research, and SCD and JP have an investigator-initiated partnership grant with AstraZeneca for unrelated research. MJA additionally holds investigator-initiated grants from Pfizer, Boehringer-Ingelheim and Sanofi for unrelated research; has undertaken an unrelated consultancy for Sanofi; and received a speaker’s fee from GlaxoSmithKline. KH has received personal fees and non-financial support from Astra Zeneca, GlaxoSmithKline, Novartis, Chiesi, Boehringer Ingelheim and Teva outside the submitted work. KH has also received fees for performing spirometry and for training health professionals in spirometry testing., (© Author(s) (or their employer(s)) 2023. Re-use permitted under CC BY-NC. No commercial re-use. See rights and permissions. Published by BMJ.)

Background: Interest in lifetime lung function trajectories has increased in the context of emerging evidence that chronic obstructive pulmonary disease (COPD) can arise from multiple disadvantaged lung function pathways, including those that stem from poor lung function in childhood. To our knowledge, no previous study has investigated both obstructive and restrictive lifetime patterns concurrently, while accounting for potential overlaps between them. We aimed to investigate lifetime trajectories of the FEV 1 /forced vital capacity (FVC) ratio, FVC, and their combinations, relate these combined trajectory groups to static lung volume and gas transfer measurements, and investigate both risk factors for and consequences of these combined trajectory groups., Methods: Using z scores from spirometry measured at ages 7, 13, 18, 45, 50, and 53 years in the Tasmanian Longitudinal Health Study (n=2422), we identified six FEV 1 /FVC ratio trajectories and five FVC trajectories via group-based trajectory modelling. Based on whether trajectories of the FEV 1 /FVC ratio and FVC were low (ie, low from childhood or adulthood) or normal, four patterns of lifetime spirometry obstruction or restriction were identified and compared against static lung volumes and gas transfer. Childhood and adulthood characteristics and morbidities of these patterns were investigated., Findings: The prevalence of the four lifetime spirometry patterns was as follows: low FEV 1 /FVC ratio only, labelled as obstructive-only, 25·8%; low FVC only, labelled as restrictive-only, 10·5%; both low FEV 1 /FVC ratio and low FVC, labelled as mixed, 3·5%; and neither low FEV 1 /FVC ratio nor low FVC, labelled as reference, 60·2%. The prevalence of COPD at age 53 years was highest in the mixed pattern (31 [37%] of 84 individuals) followed by the obstructive-only pattern (135 [22%] of 626 individuals). Individuals with the mixed pattern also had the highest prevalence of parental asthma, childhood respiratory illnesses, adult asthma, and depression. Individuals with the restrictive-only pattern had lower total lung capacity and residual volume, and had the highest prevalence of childhood underweight, adult obesity, diabetes, cardiovascular conditions, hypertension, and obstructive sleep apnoea., Interpretation: To our knowledge, this is the first study to characterise lifetime phenotypes of obstruction and restriction simultaneously using objective data-driven techniques and unique life course spirometry measures of FEV 1 /FVC ratio and FVC from childhood to middle age. Mixed and obstructive-only patterns indicate those who might benefit from early COPD interventions. Those with the restrictive-only pattern had evidence of true lung restriction and were at increased risk of multimorbidity by middle age., Funding: National Health and Medical Research Council of Australia, The University of Melbourne, Clifford Craig Medical Research Trust of Tasmania, The Victorian, Queensland & Tasmanian Asthma Foundations, The Royal Hobart Hospital, Helen MacPherson Smith Trust, and GlaxoSmithKline., Competing Interests: Declaration of interests CJL, EHW, AJL, DSB, MJA, JLP, and SCD hold an investigator-initiated grant from GlaxoSmithKline for unrelated research. SCD holds an investigator-initiated grant from AstraZeneca for unrelated research. MJA holds investigator-initiated grants from Pfizer, Boehringer Ingelheim, and Sanofi for unrelated research; has undertaken an unrelated consultancy for and received assistance with conference attendance from Sanofi; and received speaker's fees from GlaxoSmithKline. AJL has received non-financial support from Primus Pharmaceuticals for unrelated research. All other authors declare no competing interests., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

Background: While the relationship between pollen and respiratory allergies is well-documented, the role of short-term pollen exposure in food allergy and eczema flares has not previously been explored. We aimed to investigate these associations in a population-based sample of children., Methods: We investigated 1- (n = 1108) and 6-year-old (n = 675) children in the grass pollen season from the HealthNuts cohort. Grass pollen concentrations were considered on the day of testing (lag 0), up to three days before (lag 1-lag 3) and cumulatively (lag 0-3). Associations between grass pollen and food skin-prick test reactivity (SPT ≥ 2 mm at age 1 year and ≥ 3 mm at age 6 years), eczema flares, challenge-confirmed food allergy, reaction threshold to oral food challenges (OFC), and serum food-specific IgE levels were analyzed using either logistic or quantile regression models. Atopy and family history of allergic disease were considered as potent effect modifiers., Results: Grass pollen at lag 0-3 (every 20 grains/m 3 increase) was associated with an up to 1.2-fold increased odds of food SPT reactivity and eczema flares in 6-year-olds. In 1-year-olds, the associations were only observed for peanut in those with a family history of food allergy. Increasing grass pollen concentrations were associated with a lower reaction threshold to OFC and higher serum IgE levels in peanut-allergic 1-year-olds only., Conclusion: Increasing grass pollen concentration was associated with increased risk of food SPT reactivity and eczema flares in children. The associations in peanut-allergic infants may be related to immune activation and/or peanut and grass pollen cross-reactivity leading to a lower reaction threshold., (© 2022 The Authors. Pediatric Allergy and Immunology published by European Academy of Allergy and Clinical Immunology and John Wiley & Sons Ltd.)

Background: Grass pollen exposure is a risk factor for childhood asthma hospital attendances. However, its short-term influence on lung function, especially among those with other allergic conditions, has been less well-studied., Objective: To investigate this association in a population-based sample of children., Methods: Within the HealthNuts cohort, 641 children performed spirometry during the grass pollen season. Grass pollen concentration was considered on the day of testing (lag 0), up to 3 days before (lag 1-lag 3), and cumulatively (lag 0-3). We used linear regression to assess the relevant associations and examined potential interactions with current asthma, hay fever or eczema, and food allergy., Results: Associations were observed only in children with allergic disease (P value for interaction ≤ 0.1). In children with food allergy, grass pollen concentration was associated with a lower ratio of forced expiratory volume in 1 second to forced vital capacity (FEV 1 /FVC) and lower mid-forced expiratory flows (FEF 25%-75% ) at all lags (eg, at lag 2, FEV 1 /FVC z-score = -0.50 [95% CI -0.80 to -0.20] and FEF 25%--75% z-score = -0.40 [-0.60 to -0.04] per 20 grains/m 3 pollen increase), and increased bronchodilator responsiveness (BDR) at lag 2 and lag 3 (eg, at lag 2, BDR = (31 [95% CI -0.005 to 62] mL). In children with current asthma, increasing grass pollen concentration was associated with lower FEF 25%-75% and increased BDR, whereas children with current hay fever or eczema had increased BDR only., Conclusions: A proactive approach needs to be enforced to manage susceptible children, especially those with food allergy, before high-grass pollen days., (Copyright © 2022 American Academy of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.)

Respiratory diseases such as asthma, allergic rhinitis (AR) and chronic obstructive pulmonary disease (COPD) affect millions worldwide and pose a significant global public health burden. Over the years, changes in land use and climate have increased pollen quantity, allergenicity and duration of the pollen season, thus increasing its impact on respiratory disease. Many studies have investigated the associations between short-term ambient pollen (i.e., within days or weeks of exposure) and respiratory outcomes. Here, we reviewed the current evidence on the association between short-term outdoor pollen exposure and thunderstorm asthma (TA), asthma and COPD hospital presentations, general practice (GP) consultations, self-reported respiratory symptoms, lung function changes and their potential effect modifiers. The literature suggests strong evidence of an association between ambient pollen concentrations and almost all respiratory outcomes mentioned above, especially in people with pre-existing respiratory diseases. However, the evidence on sub-clinical lung function changes, COPD, and effect modifiers other than asthma, hay fever and pollen sensitisation are still scarce and requires further exploration. Better understanding of the implications of pollen on respiratory health can aid healthcare professionals to implement appropriate management strategies.

Despite the challenges of diagnosing and managing adult patients with chronic cough, a systematic synthesis of evidence on aetiological risk factor is lacking. We systematically searched PubMed and EMBASE to synthesize the current evidence for longitudinal associations between a wide range of risk factors and chronic cough in the general adult population, following the meta-analysis of observational studies in epidemiology (MOOSE) guidelines. The Newcastle-Ottawa scale was used to assess the quality of the included studies. Fixed-effect meta-analysis was conducted where appropriate. Of 26 eligible articles, 16 domains of risk factors were assessed. There was consistent evidence that asthma (pooled adjusted OR [aOR] = 3.01; 95% CI: 2.33-3.70; I 2  = 0%; number of articles [N] = 3) and low education levels/socioeconomic status (SES) (pooled aOR = 1.46; 95% CI: 1.20-1.72; I 2  = 0%; N = 3) were associated with an increased risk of chronic cough after adjusting for smoking and other confounders. While continuous smoking was associated with chronic cough (aOR = 1.81; 95% CI: 1.36-2.26; I 2  = 57%; N = 3), there was too little evidence to draw conclusions for occupational exposures, outdoor air pollution, early-life exposures, diet, snoring and other chronic conditions, including obesity, chronic obstructive pulmonary disease, gastro-oesophageal reflux disease and chronic pain. Asthma, persistent smoking and lower education/SES were associated with an increased risk of chronic cough. Longitudinal associations between other factors frequently mentioned empirically (i.e., occupational exposures, air pollution and chronic respiratory conditions) need further investigation, ideally with objective and standardized measurement., (© 2021 Asian Pacific Society of Respirology.)

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)., (© 2021 John Wiley & Sons Ltd.)

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 (FEF 25%-75% ) and FEV 1 /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., (© 2020 EAACI and John Wiley and Sons A/S. Published by John Wiley and Sons Ltd.)

Background: Thunderstorm asthma is defined as epidemics of asthma occurring shortly after a thunderstorm. While grass pollen has been implicated in thunderstorm asthma events, little is known about the role of fungi and studies have not been synthesised., Objective: This systematic review aims to evaluate whether grass pollen is necessary in thunderstorm asthma events and whether fungi also play a part in these associations., Methods: We conducted a systematic search using six electronic databases (i.e. CINAHL, Medline (Ovid), Web of Science, ProQuest Central, EMBASE and Google Scholar) and checked reference lists. The search terms used were pollen AND thunderstorm* AND asthma. The inclusion criteria were studies published in English with original human data relating to outdoor pollen and thunderstorm asthma., Results: Twenty of 2198 studies were eligible. Reported findings differed due to variation in methodological approaches and a meta-analysis was not possible. Nonetheless, of the 20 studies included, 15 demonstrated some relationship with nine demonstrating lagged effects up to four days for increasing grass pollen counts associated with increased risk of thunderstorm asthma. Of the 10 studies that examined fungi, nine demonstrated a positive relationship with thunderstorm asthma. The fungal taxa involved varied, depending on whether measurements were recorded before, during or after the thunderstorm. Nevertheless, none of the studies considered fungi as a potential effect modifier for the pollen-thunderstorm asthma association., Conclusion: We found evidence to suggest that grass pollen was a necessary factor for thunderstorm asthma but there are other as yet unrecognised environmental factors that may also be important. Further research is required to examine the role of fungi and other environmental factors such as air quality as potential effect modifiers of the association., Competing Interests: Declaration of competing interest Michael Abramson holds investigator-initiated grants from Pfizer and Boehringer-Ingelheim for unrelated research. He has also undertaken an unrelated consultancy for Sanofi., (Crown Copyright © 2019. Published by Elsevier Inc. All rights reserved.)