Childhood wheeze phenotypes show less than expected growth in FEV1 across adolescence

Machine learning-derived asthma and allergy trajectories in children: a systematic review and meta-analysis

INTRODUCTION

Numerous studies have characterised trajectories of asthma and allergy in children using machine learning, but with different techniques and mixed findings. The present work aimed to summarise the evidence and critically appraise the methodology.

METHODS

10 databases were searched. Screening, data extraction and quality assessment were performed in pairs. Trajectory characteristics were tabulated and visualised. Associated risk factor and outcome estimates were pooled using a random-effects meta-analysis.

RESULTS

89 studies were included. Early-onset (infancy) persistent, mid-onset (∼2-5 years) persistent, early-onset early-resolving (within ∼2 years) and early-onset mid-resolving (by ∼3-6 years) wheezing and eczema, respectively, were the most commonly identified disease trajectories. Intermediate/transient trajectories were rare. Male sex was associated with a higher risk of most wheezing trajectories and possibly with early-resolving eczema, while being slightly protective against mid-onset persistent eczema. Parental disease/genetic markers were associated with persistent trajectories of wheezing and eczema, respectively. Prenatal (and less so postnatal) tobacco smoke exposure was associated with most wheezing trajectories, as were lower respiratory tract infections in infancy (particularly with the early-onset resolving patterns). Most studies (69%) were of low methodological quality (particularly in modelling approaches and reporting). Few studies investigated allergic multimorbidity, allergic rhinitis and food allergy.

CONCLUSIONS

Childhood asthma/wheezing and eczema can be characterised by a few relatively consistent trajectories, with some actionable risk factors such as pre-/postnatal smoke exposure. Improved computational methodology is warranted to better assess generalisability and elucidate the validity of intermediate/transient trajectories. Likewise, allergic multimorbidity and trajectories of allergic rhinitis and food allergy need to be further elucidated.

Predictors of lung function in early adulthood: A population-based cohort study

BACKGROUND AND OBJECTIVE

Lung function reaches a peak/plateau in early adulthood before declining with age. Lower early adult lung function may increase the risk for chronic obstructive pulmonary disease (COPD) in mid-late adult life. Understanding the effects of multiple childhood/adolescent exposures and their potential interactions on plateau lung function would provide insights into the natural history of COPD.

METHODS

Longitudinal spirometry data from 688 participants with complete data from a population-based birth cohort (original n = 1037) were used to investigate associations between a wide range of childhood/adolescent exposures and repeated measures of FEV1, FVC and FEV1/FVC during the early-adult plateau phase. Generalized estimating equations were used to accommodate the multiple timepoints per participant.

RESULTS

FEV1 reached a peak/plateau between ages 18 and 26 and FVC from 21 to 32 years, whereas FEV1/FVC declined throughout early adulthood. Childhood asthma and airway hyperresponsiveness were associated with lower early adult FEV1 and FEV1/FVC. Smoking by age 18 was associated with lower FEV1/FVC. Higher BMI during early adulthood was associated with lower FEV1 and FVC and lower FEV1/FVC. Physical activity during adolescence was positively associated with FEV1 and FEV1/FVC but this was only statistically significant in men. There was no convincing evidence of interactions between exposures.

CONCLUSION

Childhood asthma and airway hyperresponsiveness are associated with lower lung function in early adulthood. Interventions targeting these may reduce the risk of COPD in mid-late adult life. Promotion of physical activity during adolescence, prevention of cigarette smoking and maintenance of a healthy body weight in early adulthood are also priorities.

Physical activity and body mass related to catch-up lung function growth in childhood: a population-based accelerated cohort study

OBJECTIVE

The existence of catch-up lung function growth and its predictors is uncertain. We aimed to identify lung function trajectories and their predictors in a population-based birth cohort.

METHODS

We applied group-based trajectory modelling to z-scores of forced expiratory volume in 1 second (zFEV1) and z-scores of forced vital capacity (zFVC) from 1151 children assessed at around 4, 7, 9, 10, 11, 14 and 18 years. Multinomial logistic regression models were used to test whether potential prenatal and postnatal predictors were associated with lung function trajectories.

RESULTS

We identified four lung function trajectories: a low (19% and 19% of the sample for zFEV1 and zFVC, respectively), normal (62% and 63%), and high trajectory (16% and 13%) running in parallel, and a catch-up trajectory (2% and 5%) with catch-up occurring between 4 and 10 years. Fewer child allergic diseases and higher body mass index z-score (zBMI) at 4 years were associated with the high and normal compared with the low trajectories, both for zFEV1 and zFVC. Increased children's physical activity during early childhood and higher zBMI at 4 years were associated with the catch-up compared with the low zFEV1 trajectory (relative risk ratios: 1.59 per physical activity category (1.03-2.46) and 1.47 per zBMI (0.97-2.23), respectively). No predictors were identified for zFVC catch-up growth.

CONCLUSION

We found three parallel-running and one catch-up zFEV1 and zFVC trajectories, and identified physical activity and body mass at 4 years as predictors of zFEV1 but not zFVC catch-up growth.

Repurposing lipid-lowering drugs on asthma and lung function: evidence from a genetic association analysis

OBJECTIVE

To explore the correlation between asthma risk and genetic variants affecting the expression or function of lipid-lowering drug targets.

METHODS

We conducted Mendelian randomization (MR) analyses using variants in several genes associated with lipid-lowering medication targets: HMGCR (statin target), PCSK9 (alirocumab target), NPC1L1 (ezetimibe target), APOB (mipomersen target), ANGPTL3 (evinacumab target), PPARA (fenofibrate target), and APOC3 (volanesorsen target), as well as LDLR and LPL. Our objective was to investigate the relationship between lipid-lowering drugs and asthma through MR. Finally, we assessed the efficacy and stability of the MR analysis using the MR Egger and inverse variance weighted (IVW) methods.

RESULTS

The elevated triglyceride (TG) levels associated with the APOC3, and LPL targets were found to increase asthma risk. Conversely, higher LDL-C levels driven by LDLR were found to decrease asthma risk. Additionally, LDL-C levels (driven by APOB, NPC1L1 and HMGCR targets) and TG levels (driven by the LPL target) were associated with improved lung function (FEV1/FVC). LDL-C levels driven by PCSK9 were associated with decreased lung function (FEV1/FVC).

CONCLUSION

In conclusion, our findings suggest a likely causal relationship between asthma and lipid-lowering drugs. Moreover, there is compelling evidence indicating that lipid-lowering therapies could play a crucial role in the future management of asthma.

Caregivers' Perceptions, Needs, and Data Sharing Concerns in mHealth Research on Pediatric Asthma: Cross-Sectional Survey Study

Background

Pediatric asthma is the most common chronic respiratory disease of childhood. Caregivers often report lacking knowledge in several aspects of asthma management at home. Although the use of mobile health (mHealth) tools, such as mobile apps, could facilitate asthma self-management and, simultaneously, the collection of data for research, few studies have explored the features that caregivers would like to see in such a tool and their perceptions on data sharing.

Objective

This study evaluates caregivers' perceived knowledge gaps in asthma management; their perceptions of certain features and resources that should be included in a potential mobile app; and any concerns that they may have regarding data sharing for research, including privacy and security concerns.

Methods

In this cross-sectional study, we surveyed 200 caregivers of children (aged 1-13 y) with asthma who were followed at a pediatric tertiary care center in Montreal, Canada. Anonymous data were collected through the institutional web-based survey platform. We collected the participants' answers by using a 5-category Likert scale ("completely agree," "agree," "neither agree nor disagree," "disagree," and "completely disagree"), multiple-choice questions, and free-text questions on the abovementioned topics. Descriptive statistics were performed, and answers were compared between caregivers of preschool-aged children and caregivers of school-aged children.

Results

Participating children's mean age was 5.9 (SD 3.4) years, with 54% (108/200) aged ≤5 years and 46% (92/200) aged >6 years. Overall, caregivers reported having adequate knowledge about asthma and asthma self-management. Nonetheless, they identified several desirable features for a mobile app focused on asthma self-management. The most frequently identified features included receiving alerts about environmental triggers of asthma (153/199, 76.9%), having videos that demonstrate symptoms of asthma (133/199, 66.8%), and being able to log children's asthma action plans in the app (133/199, 66.8%). Interestingly, more caregivers of preschool-aged children preferred textual information when compared to caregivers of school-aged children (textual information for explaining asthma: P=.008; textual information for the symptoms of asthma: P=.005). Caregivers were generally highly in favor of sharing data collected through a mobile app for research.

Conclusions

Caregivers of children with asthma in our study identified several desirable educational and interactive features that they wanted to have in a mobile app for asthma self-management. These findings provide a foundation for designing and developing mHealth tools that are relevant to caregivers of children with asthma.

Prediction of adult asthma risk in early childhood using novel adult asthma predictive risk scores

BACKGROUND

Numerous risk scores have been developed to predict childhood asthma. However, they may not predict asthma beyond childhood. We aim to create childhood risk scores that predict development and persistence of asthma up to young adult life.

METHODS

The Isle of Wight Birth Cohort (n = 1456) was prospectively assessed up to 26 years of age. Asthma predictive scores were developed based on factors during the first 4 years, using logistic regression and tested for sensitivity, specificity and area under the curve (AUC) for prediction of asthma at (i) 18 and (ii) 26 years, and persistent asthma (PA) (iii) at 10 and 18 years, and (iv) at 10, 18 and 26 years. Models were internally and externally validated.

RESULTS

Four models were generated for prediction of each asthma outcome. ASthma PredIctive Risk scorE (ASPIRE)-1: a 2-factor model (recurrent wheeze [RW] and positive skin prick test [+SPT] at 4 years) for asthma at 18 years (sensitivity: 0.49, specificity: 0.80, AUC: 0.65). ASPIRE-2: a 3-factor model (RW, +SPT and maternal rhinitis) for asthma at 26 years (sensitivity: 0.60, specificity: 0.79, AUC: 0.73). ASPIRE-3: a 3-factor model (RW, +SPT and eczema at 4 years) for PA-18 (sensitivity: 0.63, specificity: 0.87, AUC: 0.77). ASPIRE-4: a 3-factor model (RW, +SPT at 4 years and recurrent chest infection at 2 years) for PA-26 (sensitivity: 0.68, specificity: 0.87, AUC: 0.80). ASPIRE-1 and ASPIRE-3 scores were replicated externally. Further assessments indicated that ASPIRE-1 can be used in place of ASPIRE-2-4 with same predictive accuracy.

CONCLUSION

ASPIRE predicts persistent asthma up to young adult life.

Respiratory morbidity in preschool and school-age children born very preterm and its association with parents' health-related quality of life and family functioning

The purpose of this study is to describe the prevalence and severity of respiratory symptoms in children born very preterm and to assess their association with parents' health-related quality of life (HRQoL) and family functioning. We conducted a cross-sectional study and recruited children born less than 32 weeks' gestation between January 2006 and December 2019, in the greater Zurich area, Switzerland. Between May and December 2021, parents were invited to complete an online survey for their preterm child and for a control term born (≥ 37 weeks' gestation) sibling aged 1 to 18 years. We used a validated questionnaire to assess respiratory symptoms and the Pediatrics Quality of Life Family Impact Module (PedsQL FIM) to assess parents' HRQoL and family functioning. The survey was completed for 616 very preterm children (99 with bronchopulmonary dysplasia (BPD)) and 180 controls. Girls made up 45% (46% in controls) of the sample, and 63% (60% in controls) of participants were aged 6 to 18 years (school-age). Very preterm children reported a higher risk of respiratory symptoms than controls, especially preschoolers and those with moderate-to-severe BPD. Parents of children with "mild" and "moderate-severe" respiratory symptoms had on average -3.9 (95%CI: -6.6 to -1.1) and -8.2 (-11.2 to -5.2) lower PedsQL FIM total score, respectively, than parents of children with no symptoms. The same pattern was observed after stratifying by age categories.  Conclusions: Our study suggests that respiratory morbidity in very preterm children has a negative impact on parents' HRQoL and family functioning, even beyond the first years of life. What is Known: • The burden of respiratory morbidity associated with very premature birth is high and last far beyond the neonatal period. • Respiratory morbidity contributes to lower health-related quality of life (HRQoL) in parents of very preterm children in early infancy. What is New: • Respiratory morbidity in very preterm children has a negative impact on parents' HRQoL and family functioning beyond the first years of life. • Parents of very preterm children with moderate and severe respiratory symptoms are the ones who report lower scores, both for preschool and school-age children.

Towards the elimination of chronic obstructive pulmonary disease: a Lancet Commission

Despite substantial progress in reducing the global impact of many non-communicable diseases, including heart disease and cancer, morbidity and mortality due to chronic respiratory disease continues to increase. This increase is driven primarily by the growing burden of chronic obstructive pulmonary disease (COPD), and has occurred despite the identification of cigarette smoking as the major risk factor for the disease more than 50 years ago. Many factors have contributed to what must now be considered a public health emergency: failure to limit the sale and consumption of tobacco products, unchecked exposure to environmental pollutants across the life course, and the ageing of the global population (partly as a result of improved outcomes for other conditions). Additionally, despite the heterogeneity of COPD, diagnostic approaches have not changed in decades and rely almost exclusively on post-bronchodilator spirometry, which is insensitive for early pathological changes, underused, often misinterpreted, and not predictive of symptoms. Furthermore, guidelines recommend only simplistic disease classification strategies, resulting in the same therapeutic approach for patients with widely differing conditions that are almost certainly driven by variable pathophysiological mechanisms. And, compared with other diseases with similar or less morbidity and mortality, the investment of financial and intellectual resources from both the public and private sector to advance understanding of COPD, reduce exposure to known risks, and develop new therapeutics has been woefully inadequate.

Novel Lung Growth Strategy with Biological Therapy Targeting Airway Remodeling in Childhood Bronchial Asthma

Anti-inflammatory therapy, centered on inhaled steroids, suppresses airway inflammation in asthma, reduces asthma mortality and hospitalization rates, and achieves clinical remission in many pediatric patients. However, the spontaneous remission rate of childhood asthma in adulthood is not high, and airway inflammation and airway remodeling persist after remission of asthma symptoms. Childhood asthma impairs normal lung maturation, interferes with peak lung function in adolescence, reduces lung function in adulthood, and increases the risk of developing chronic obstructive pulmonary disease (COPD). Early suppression of airway inflammation in childhood and prevention of asthma exacerbations may improve lung maturation, leading to good lung function and prevention of adult COPD. Biological drugs that target T-helper 2 (Th2) cytokines are used in patients with severe pediatric asthma to reduce exacerbations and airway inflammation and improve respiratory function. They may also suppress airway remodeling in childhood and prevent respiratory deterioration in adulthood, reducing the risk of COPD and improving long-term prognosis. No studies have demonstrated a suppressive effect on airway remodeling in childhood severe asthma, and further clinical trials using airway imaging analysis are needed to ascertain the inhibitory effect of biological drugs on airway remodeling in severe childhood asthma. In this review, we describe the natural prognosis of lung function in childhood asthma and the risk of developing adult COPD, the pathophysiology of allergic airway inflammation and airway remodeling via Th2 cytokines, and the inhibitory effect of biological drugs on airway remodeling in childhood asthma.

Predicting the course of asthma from childhood until early adulthood

PURPOSE OF REVIEW

To communicate recent insights about the natural history of childhood asthma, with a focus on prediction of persistence and remission of childhood asthma, up to early adulthood.

RECENT FINDINGS

Lung function around the age of 8-9 years is the strongest predictor: obstructive lung function predicts asthma persistence up to early adulthood, whereas normal lung function predicts remission. The ability to predict asthma remission improves when lung function is combined with blood eosinophil levels and degree of bronchial hyperresponsiveness. Interventions, such as inhaled corticosteroids and immunotherapy do not appear to alter the course of asthma. Epigenetic studies have revealed potential novel biomarkers of asthma remission, such as micro-RNA patterns in blood. Specifically, lower serum levels of mi-R221-5p, which is associated with lower IL-6 release and eosinophilic inflammation, predict remission. Higher levels of blood DNA-methylation of a CpG site in Peroxisomal Biogenesis Factor 11 Beta were associated with asthma remission.

SUMMARY

Lung function, allergic comorbidity and polysensitization in childhood predict the course of asthma. Recent epigenetic studies have provided a better understanding of underlying pathological processes in asthma remission, which may be used to improve prediction or develop novel treatments aimed at altering the course of asthma.

Wheezing trajectories from childhood to adulthood in a population-based cohort

BACKGROUND

Wheezing may lead to asthma and reduced pulmonary function in later life. The study aims to identify wheezing trajectories and investigate their relation with pulmonary function and asthma-related outcomes at 22 years of age.

METHODS

Individuals from a population-based cohort in Brazil (1993 Pelotas Birth Cohort) with post-bronchodilator pulmonary function data at 22 years (3350) were included in the study. From parentally reported (4 and 11 years) and self-reported (15, 18 and 22 years) history of wheezing in the last 12 months, we used a group-based trajectory modelling approach to derive wheezing trajectories.

RESULTS

Four trajectories were identified: never/infrequent, transient-early, late-onset and persistent wheeze. After adjustments, wheezing trajectories remained associated with lower post-bronchodilator values of pulmonary function. Individuals in the persistent wheeze trajectory had a markedly poorer pulmonary function and also showed greater odds of asthma-related outcomes compared to other trajectories groups. Those following this trajectory had on average -109 ml (95% CI: -188; -35), -1.80 percentage points (95% CI: -2.73; -0.87) and -316 ml/s (95% CI: -482; -150) lower FEV₁, FEV₁/FVC ratio and FEF_25-75% respectively; higher odds of self-reported medical diagnosis of allergy (OR 6.18; 95% CI: 3.59; 10.61) and asthma (OR 12.88; 95% CI: 8.91; 18.61) and asthma medication use (OR 9.42; 95% CI: 5.27; 16.87) compared to the never/infrequent group.

CONCLUSIONS

Wheezing trajectories, especially the persistent wheeze trajectory, were related to lower pulmonary function values and increased risk of asthma and allergy diagnosis in early adulthood.

Air pollution-related asthma profiles among children/adolescents: A multi-group latent class analysis

BACKGROUND

This study aimed to investigate the asthma profile among children/adolescents and the relationship of the prevalence of air pollution profiles using latent class analysis (LCA).

OBJECTIVES

In this cross-sectional study, a case rural community was selected in an industrial area, and two rural control communities were selected in unexposed areas.

METHODS

Hourly concentrations of PM₁₀, SO₂, NO_2, and total volatile organic compounds were obtained from the records of a fixed air quality monitoring station, and the concentrations of benzene, toluene, xylenes styrene were measured during six campaigns. Asthma data was collected using the International Study of Asthma and Allergies in Childhood in 7-18 years old children/adolescents. The modeling was conducted using LCA.

RESULTS

A higher amount of air pollution indices were observed in the case than both control communities. LCA divided the participants into three clusters; "healthy" (92.8%), "moderate" (2.8%), and "severe" (4.4%). A higher probability of severe asthma (6.8%) was observed in the case than control communities (2.6% and 1.8%). Additionally, after adjusting for possible confounders, the odds of asthma was lower in the control communities than the case in both moderate and sever classes (Odds Ratios in the range of 0.135-0.697).

CONCLUSIONS

This study indicates asthma profiles of children/adolescents and the higher prevalence of severe class in the area, explaining the possible effect of air pollution.

Asthma, bronchial hyperresponsiveness, allergy and lung function development until early adulthood: A systematic literature review

BACKGROUND

It is unclear in which periods of life lung function deficits develop, and whether these are affected by risk factors such as asthma, bronchial hyper-responsiveness (BHR) and allergic comorbidity. The goal of this systematic review was to identify temporal associations of asthma, BHR and allergic comorbidity with large and small lung function development from birth until peak function in early adulthood.

METHODS

We searched MEDLINE, EMBASE, Web of Science and CINAHL for papers published before 01.01.2020 on risk factors and lung function measurements of large and small airways. Studies were required to report lung function at any time point or interval from birth until peak lung function (age 21-26) and include at least one candidate risk factor.

RESULTS

Of the 45 papers identified, 44 investigated cohorts and one was a clinical trial with follow-up. Asthma, wheezing, BHR and allergic sensitization early in life and to multiple allergens were associated with a lower lung function growth of large and small airways during early childhood compared with the control populations. Lung function development after childhood in subjects with asthma or persistent wheeze, although continuing to grow at a lower level, largely tracked parallel to non-affected individuals until peak function was attained.

CLINICAL IMPLICATIONS AND FUTURE RESEARCH

Deficits in lung function growth develop in early childhood, and children with asthma, BHR and early-life IgE (poly)sensitization are at risk. This period is possibly a critical window of opportunity to identify at-risk subjects and provide treatment aimed at preventing long-term sequelae of lung function.

Persistent airflow obstruction in inner-city children with asthma

Background: Airway remodeling has been shown to be persistent in patients with asthma despite treatment with controller medications. Patients with early airflow obstruction may continue to experience poor lung function despite treatment. Objectives: To determine whether early airflow obstruction in inner-city children with asthma persists despite guideline-based asthma care. Methods: In a retrospective study that used a cohort of inner-city children with asthma treated by using an asthma-specific disease management system, the patients were stratified into "low" or "high" lung function groups at the time of the initial visit (high, forced expiratory volume in the first second of expiration [FEV₁] % predicted and FEV₁/forced vital capacity [FVC] ≥ 80%; and low, FEV₁% predicted and FEV₁/FVC < 80%). These patients then received National Heart, Lung, and Blood Institute guideline-based asthma treatment at regular follow-up intervals with spirometry performed at these visits as part of regular care. FEV₁% predicted and FEV₁/FVC were followed up for up to 10 years for both the high and low cohorts. Results: Over 10 years, the patients initially in the "high" group maintained FEV₁% predicted and FEV₁/FVC at values similar to the initial visit (94 to 96% and 87 to 89%, respectively), whereas those in the low group had only slight increases of FEV₁% predicted and FEV₁/FVC over the same time (77 to 82% and 78 to 82%, respectively). Low FEV₁% predicted and FEV₁/FVC at the time of the first visit was significantly associated with an increased risk of low values of these lung functions over the next 3-5 years despite treatment. African American ethnicity and male gender were also associated with lower lung function over time. Conclusion: Early airflow obstruction in inner city children asthma is associated with poor lung function in later life despite guideline-based asthma care. Current asthma therapy may not affect pathways and leads to airway remodeling in children with asthma.

Childhood wheeze trajectory-specific risk factors: A systematic review and meta-analysis

BACKGROUND

There is growing interest in the use of latent trajectory methodology to identify wheeze patterns in heterogeneous populations of children. This study systematically reviewed and meta-analyzed childhood wheeze trajectory studies to identify childhood wheeze trajectory group-specific risk factors among children from birth through to adolescence.

METHODS

We included studies that used latent trajectory methodology to identify wheeze trajectories and associated risk factors. We searched PubMed, EMBASE, and Google Scholar from 2000 through September 30, 2019, for relevant studies. The study was conducted according to the PRISMA recommendations.

RESULTS

Thirteen cohort studies conducted in eleven high-income countries were included in our meta-analysis with the length of follow-up ranging from 3 to 18 years. Five distinct latent wheeze trajectory groups were identified: Never/Infrequent, Early-Transient, Early-Persistent, Intermediate-Onset, and Late-Onset. We found moderate-to-strong evidence that family history of asthma predicted persistent childhood wheezing among male children but with lower risk among first-born children. There was weak-to-moderate evidence for childhood atopy, male sex, short duration of breastfeeding, tobacco exposure, daycare attendance, and having siblings as risk factors for Early-Transient wheezing; except for breastfeeding, these factors were also associated with intermediate and Late-Onset wheezing with varying effect sizes in high-risk vs general population cohorts.

CONCLUSIONS

Our findings confirm the consistency of wheeze trajectory groups defined by onset, peak prevalence, and duration; we also suggest a common nomenclature for future trajectory studies. With the exception of the relationship between a family history of asthma and persistent childhood wheezing, commonly suspected wheeze risk factors (childhood atopy, male sex, short duration of breastfeeding, tobacco exposure, daycare attendance, and having siblings) are not trajectory-specific and have varying effects in high-risk vs general population cohorts. Delineation of time-varying risk factor effects may be critical to the specificity of wheeze trajectory group prediction to better inform prognosis and targeted early preventive intervention among at-risk children.

Trajectories of asthma and allergies from 7 years to 53 years and associations with lung function and extrapulmonary comorbidity profiles: a prospective cohort study

BACKGROUND

Longitudinal trajectories of asthma and allergies from childhood to adulthood might be differentially associated with lung function and chronic obstructive pulmonary disease (COPD), but associations with extrapulmonary comorbidities have not been well investigated. We aimed to assess these trajectories and examine their associations with lung function outcomes and profiles of comorbidities.

METHODS

In this prospective cohort study, data for asthma and related allergic conditions (ie, eczema, hay fever, and food allergy) were prospectively collected from the Tasmanian Longitudinal Health Study for participants aged 7-53 years originally recruited in Tasmania, Australia. All surviving individuals in the database with contact details were invited in the most recent follow-up (mean age 53 years). There were no exclusion criteria. With use of latent class analysis, we identified longitudinal trajectories of asthma and allergic conditions from 7-53 years, and profiles of self-reported extrapulmonary conditions recorded at 53 years. The associations between asthma and allergy trajectories and morbidity profiles and lung function at 53 years were investigated with regression models.

FINDINGS

Between Sept 3, 2012, and Nov 8, 2016, of 6128 individuals invited, 3609 (58·9%) individuals were enrolled. We identified five asthma and allergy trajectories: minimal and least asthma and allergies (n= 1767 [49·0%]); late-onset hay fever, no asthma (n=1065 [29·5%]); early-onset remitted asthma and allergies (n=236 [6·5%]); late-onset asthma and allergies (n=317 [8·8%]); and early-onset persistent asthma and allergies (n=224 [6·2%]); and four profiles of extrapulmonary morbidities: minimal or least disease (n=2206 [61·1%]); dominant mental health disorders (n=861 [23·9%]); dominant cardiovascular diseases or risks (n=424 [11·7%]); and multiple disorders (n=117 [3·2%]). The late-onset asthma and allergies trajectory was predominantly associated with the multiple disorders profile (relative risk ratio 3·3 [95% CI 1·9-5·9]), whereas the other asthma and allergy trajectories were associated only with the dominant mental health disorders profile. Both spirometrically defined and clinical COPD were most strongly associated with the early-onset persistent asthma and allergies trajectory (odds ratio [OR] 5·3 [95% CI 3·2-8·6]) and also with the late-onset asthma and allergies trajectory (OR 3·8 [2·4-6·1]).

INTERPRETATION

Distinct longitudinal trajectories of asthma and allergic disease from childhood to 53 years are associated with different profiles of extrapulmonary comorbidities and varying risk of COPD. These findings can inform a personalised approach in clinical guidelines and management focusing on treatable traits. Comorbidity profiles are a new target for early identification and intervention.

FUNDING

National Health and Medical Research Council of Australia, EU's Horizon 2020, 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.

Transient childhood wheeze is associated with less atopy in adolescence

BACKGROUND

The relationships between childhood wheeze phenotypes and subsequent allergic conditions other than asthma, including hay fever, eczema and sensitization, have not been widely reported. We aimed to investigate this relationship up to late adolescence.

METHODS

Using five childhood wheeze phenotypes defined from 620 children in a high-atopy risk birth cohort (Melbourne Atopy Cohort Study), we investigated their relationships with sensitization, eczema, hay fever and fractional exhaled nitric oxide (FeNO) at ages 12 and/or 18 years using logistic and linear regression models.

RESULTS

'Early Persistent wheeze' was associated with the increased risk of eczema (odds ratio: 3.69; 95% CI: 1.23, 11.12) and sensitization (4.52; 1.50, 13.64) at 12 years. 'Intermediate Onset wheeze' was associated with the increased risk of eczema at 12 years (2.57; 1.11, 5.97), hay fever at 12 (2.87; 1.44, 5.74) and 18 years (2.19; 1.20, 4.02), sensitization at 12 (2.25; 1.17, 4.34) and 18 years (2.46; 1.18, 5.12), and raised FeNO at 18 years. 'Late Onset wheeze' was associated with the increased risk of hay fever at 12 (5.18; 1.11, 24.20) and 18 years (4.20; 1.03, 17.11) and sensitization at 12 years (3.27; 0.81, 13.27). In contrast, 'Early Transient wheeze' was associated with the reduced risk of eczema (0.44; 0.20, 0.96), hay fever (0.57; 0.33, 0.99) and sensitization (0.59; 0.35, 0.99) at 18 years and a lower FeNO compared with 'Never/Infrequent wheezers'.

CONCLUSIONS

Persistent wheeze phenotypes were associated with allergic outcomes up to 18 years with 'Intermediate Onset wheeze' being the most atopic group. In contrast, 'Early Transient wheezers' had less risk of allergic outcomes at 18 years. This protective effect may reassure parents of wheezy infants and young children.

Characterization of longitudinal wheeze phenotypes from infancy to adolescence in Project Viva, a prebirth cohort study

Using data from infancy to adolescence, our analysis of longitudinal wheeze phenotypes allowed us to visualize four longitudinal wheeze trajectories (never/infrequent wheeze, mid-childhood onset wheeze, early transient wheeze, and persistent wheeze).

Early-Life Exposure to Oral Antibiotics and Lung Function Into Early Adulthood

BACKGROUND

Although there is ongoing debate regarding the impact of early postnatal exposure to antibiotics on the development of asthma, the possibility that antibiotic exposure may impair lung function has not previously been examined. Furthermore, it is unclear if specific types of antibiotics may have a greater effect, or if children with genetic mutations in the oxidative stress response glutathione S-transferase (GST) superfamily may be at greater risk.

METHODS

Parent-reported data of childhood antibiotic use from birth to 2 years, including type and indication, were collected from a birth cohort of 620 infants with a family history of allergy. Spirometry was performed at age 12 and 18 years, and results are presented as z scores. Participants were genotyped for GST-P, GST-M, and GST-T polymorphisms. Linear regression models were used to investigate the associations while adjusting for confounding factors.

RESULTS

Neither increasing days of exposure nor earlier exposure to antibiotics was associated with reduced FEV₁ (at 18 years, per doubling of days of exposure = -0.03 z score units; 95% CI, -0.11 to 0.04) or FVC (< 0.01; 95% CI, -0.08 to 0.07). There was no evidence that GST-risk polymorphisms (M1, P1, and T1) increased susceptibility, and specific types of antibiotics also did not increase risk of lung function deficits.

CONCLUSIONS

Increasing exposure to oral antibiotics in early postnatal life was not associated with reduced lung function in children with a family history of allergic diseases. Although unwarranted use of antibiotics in children should be minimized, concerns regarding long-term lung health should not be a driving influence for this rationalization of use.

Pollen exposure at birth and adolescent lung function, and modification by residential greenness

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.

Influence of Childhood Asthma and Allergies on Occupational Exposure in Early Adulthood: A Prospective Cohort Study

We aimed to determine whether history of asthma/allergies in childhood was associated with avoidance of jobs with exposure to asthmagens in early adulthood. The Melbourne Atopic Cohort Study recruited 620 children at high risk of allergic diseases at birth (1990–1994). Asthma, hay fever and eczema were evaluated by questionnaires during childhood. A follow-up in early adulthood (mean age: 18 years) collected information on the current job. Occupational exposure to asthmagens/irritants was evaluated using a job-exposure matrix. The association between history of asthma/allergies in childhood and working in a job with exposure to asthmagens/irritants was evaluated by logistic regression, adjusted for age, sex and parental education. Among 363 participants followed-up until early adulthood, 17% worked in a job with exposure to asthmagens/irritants. History of asthma (35%) was not associated with working in an exposed job (adjusted OR: 1.16, 95% CI: 0.65–2.09). Subjects with history of hay fever (37%) and eczema (40%) were more likely to enter exposed jobs (significant for hay fever: 1.78, 1.00–3.17; but not eczema: 1.62, 0.91–2.87). In conclusion, young adults with history of allergies were more likely to enter exposed jobs, suggesting no avoidance of potentially hazardous exposures. Improved counselling against high risk jobs may be needed for young adults with these conditions.

Comparison of the Associations of Early-Life Factors on Wheezing Phenotypes in Preterm-Born Children and Term-Born Children

Although respiratory symptoms, including wheezing, are common in preterm-born subjects, the natural history of the wheezing phenotypes and the influence of early-life factors and characteristics on phenotypes are unclear. Participants from the Millennium Cohort Study who were born between 2000 and 2002 were studied at 9 months and at 3, 5, 7, and 11 years. We used data-driven methods to define wheezing phenotypes in preterm-born children and investigated whether the association of early-life factors and characteristics with wheezing phenotypes was similar between preterm- and term-born children. A total of 1,049/1,502 (70%) preterm-born children and 12,307/17,063 (72%) term-born children had recent wheeze data for 3 or 4 time points. Recent wheeze was more common at all time points in the preterm-born group than in term-born group. Four wheezing phenotypes were defined for both groups: no/infrequent, early, persistent, and late. Early-life factors and characteristics, especially antenatal maternal smoking, atopy, and male sex, were associated with increased rates for all phenotypes in both groups, and breastfeeding was protective in both groups, except late wheeze in the preterm group. Preterm-born children had similar phenotypes to term-born children. Although early-life factors and characteristics were similarly associated with the wheezing phenotypes in both groups, the preterm-born group had higher rates of early and persistent wheeze. However, a large proportion of preterm-born children had early wheeze that resolved with time.

The Role of Early Life Food Sensitization in Adolescent Lung Function: Results from 2 Birth Cohort Studies

BACKGROUND

It is unclear whether early life food sensitization (as opposed to aeroallergen sensitization) is associated with subsequent poor lung function.

OBJECTIVES

We investigated the associations between food sensitization in the first 2 years of life and lung function at 12 to 18 years and whether these observed associations are mediated through aeroallergen sensitization or asthma.

METHODS

We used data from a high-risk cohort (Melbourne Atopy Cohort Study [MACS]) and a population-based "Influence of life-style-related factors on the development of the Immune System and Allergies in East and West Germany plus the influence of traffic emissions and genetics" (LISAplus) cohort. Food sensitization was assessed at 6, 12, and 24 months in MACS and 24 months in LISAplus. Lung function was evaluated by spirometry at 12 and 18 years in MACS and 15 years in LISAplus. Linear regression models were used to estimate the association with sensitization (food and/or aeroallergen) while adjusting for potential confounders.

RESULTS

Sensitization to food without aeroallergen at 6 months was associated with reduced forced expiratory volume in 1 second (FEV₁) at both 12 years (-153 mL; 95% confidence interval [CI] = -256 mL, -51 mL) and 18 years (-206 mL; 95% CI = -347 mL, -65 mL) in MACS. Similar results were observed for sensitization measured at 12 months but not at 24 months. Early-life asthma (but not aeroallergen sensitization) partially mediated these associations. Both cohorts showed that only aeroallergen sensitization at 24 months but not food sensitization was associated with lower adolescent lung function.

CONCLUSIONS

This study showed that food sensitization at 6 and 12 months was associated with reduced FEV₁ in adolescence. Our finding that this link is not completely mediated by either subsequent asthma or aeroallergen sensitization is novel and suggests that early food sensitization itself can be used to identify high-risk groups for poor lung health.

Exploring factors associated with health disparities in asthma and poorly controlled asthma among school-aged children in the U.S

Objective: Certain populations suffer disproportionately from asthma and asthma morbidity. The objective was to provide a national descriptive profile of asthma control and treatment patterns among school-aged children (SAC: aged 6-17) in the U.S. Methods: This was a cross-sectional analysis using the nationally representative 2007-2014 Medical Expenditure Panel Survey. Among SAC with asthma, indicators of poor control included: exacerbation/asthma attack; >3 canisters short-acting beta agonist (SABA)/3 months; and asthma-specific Emergency Department or inpatient visits (ED/IP). Results: Non-Hispanic black, non-Hispanic multiple races, Puerto Rican, obese, Medicaid, poor, ≥2 non-asthma chronic comorbidities (CC), and family average CC ≥ 2 were associated with higher odds of having asthma. The following had significantly higher odds ratios (OR) of excessive SABA use compared to non-Hispanic whites [OR; CI; p < 0.05]: Puerto Rican (3.8; 2.1-6.9), Mexican (3.6; 2.0-6.4), Central/South American (3.0; 1.2-7.7), Hispanic-other (3.1; 1.1-9.0), non-Hispanic black (2.5; 1.6-3.9), and non-Hispanic Asian (4.0; 1.7-9.2). SABA OR were also significant for Spanish spoken at home (2.5; 1.6-3.8), obese (2.1; 1.3-3.3), Medicaid (2.9; 2.0-4.1), no medical insurance (2.1; 1.1-4.1), no prescription insurance (2.5; 1.8-3.5), poor (2.8; 1.7-4.7), CC ≥ 2 (2.1; 1.6-2.8), parent-without high-school degree (2.5; 1.8-3.6), parent-SF-12 Physical Component Scale <50 (1.6; 1.2-2.1) and Mental Component Scale <50 (1.5; 1.1-2.0). Significant differences also existed across subgroups for ED/IP visits. Conclusions: There are disparities in asthma control and prevalence among certain populations in the U.S. These results provide national data on disparities in several indicators of poor asthma control beyond the standard race/ethnicity groupings.

School-aged asthma children with high fractional exhaled nitric oxide levels and lung dysfunction are at high risk of prolonged lung dysfunction

Background

Long-term management of bronchial asthma based on the fractional exhaled nitric oxide (FeNO) value alone is not conclusive yet. Therefore, we combined FeNO testing and spirometry, a commonly used test in routine practice, to evaluate acute exacerbation and respiratory function in children with bronchial asthma.

Objective

We combined FeNO testing and spirometry, commonly used in routine practice, to evaluate acute exacerbations and respiratory function in children with bronchial asthma.

Methods

Subjects were school aged children 7 years and older with bronchial asthma who underwent FeNO testing in January 2015 to May 2016. We evaluated the changes in the frequency of acute exacerbations and respiratory function in the 30 subsequent months. Subjects were divided into 2 groups: those with initial FeNO levels ≥ 21 parts per billion (ppb) (high FeNO) and < 20 ppb (normal FeNO) groups.

Results

There were 48 children (33 boys) in the high FeNO group and 68 children (46 boys) in the normal FeNO group. Spirometry was conducted on 83 children (72%) prior to the initial FeNO test, revealing no difference in the ratio of detecting lung dysfunction between the 2 groups. The observation period was 25.8 ± 0.7 and 24.7 ± 0.6 months for the high and normal FeNO groups, respectively. The children in the high FeNO group with lung dysfunction in the initial FeNO test continued to exhibit lung dysfunction at the test at 30 months. In the normal FeNO group, even if lung dysfunction was observed at the initial FeNO, it improved within the 20-month point, and the improvement was maintained thereafter.

Conclusion

Children with bronchial asthma with high FeNO levels and lung dysfunction are at a higher risk of prolonged lung dysfunction.

Epidemiology of Asthma in Children and Adults

Asthma is a globally significant non-communicable disease with major public health consequences for both children and adults, including high morbidity, and mortality in severe cases. We have summarized the evidence on asthma trends, environmental determinants, and long-term impacts while comparing these epidemiological features across childhood asthma and adult asthma. While asthma incidence and prevalence are higher in children, morbidity, and mortality are higher in adults. Childhood asthma is more common in boys while adult asthma is more common in women, and the reversal of this sex difference in prevalence occurs around puberty suggesting sex hormones may play a role in the etiology of asthma. The global epidemic of asthma that has been observed in both children and adults is still continuing, especially in low to middle income countries, although it has subsided in some developed countries. As a heterogeneous disease, distinct asthma phenotypes, and endotypes need to be adequately characterized to develop more accurate and meaningful definitions for use in research and clinical settings. This may be facilitated by new clustering techniques such as latent class analysis, and computational phenotyping methods are being developed to retrieve information from electronic health records using natural language processing (NLP) algorithms to assist in the early diagnosis of asthma. While some important environmental determinants that trigger asthma are well-established, more work is needed to define the role of environmental exposures in the development of asthma in both children and adults. There is increasing evidence that investigation into possible gene-by-environment and environment-by-environment interactions may help to better uncover the determinants of asthma. Therefore, there is an urgent need to further investigate the interrelationship between environmental and genetic determinants to identify high risk groups and key modifiable exposures. For children, asthma may impair airway development and reduce maximally attained lung function, and these lung function deficits may persist into adulthood without additional progressive loss. Adult asthma may accelerate lung function decline and increase the risk of fixed airflow obstruction, with the effect of early onset asthma being greater than late onset asthma. Therefore, in managing asthma, our focus going forward should be firmly on improving not only short-term symptoms, but also the long-term respiratory and other health outcomes.

Asthma in the Preschool Age Child

Wheeze in preschool children (5 years of age and younger) is common. The majority of severe episodes are triggered by viral colds. Unlike atopic asthma in adults and young people, the underlying pathology of this condition is poorly understood, and the label of “preschool wheeze” should therefore not be regarded as a diagnosis but a description of symptoms. It is important to consider other causes of wheeze, but, for the most part, serious conditions such as cystic fibrosis and foreign body aspiration are associated with atypical features on careful history and examination. There remain significant uncertainties about the optimal management of children with this condition. Short-acting bronchodilators are indicated for the acute treatment of wheeze, and current evidence suggests that daily inhaled corticosteroid therapy is an effective preventive therapy, at least in a subgroup of children. Some trials suggest that preemptive therapy with inhaled corticosteroids may be as effective as regular inhaled corticosteroids. Since wheeze is intermittent for the majority of children, preemptive therapy is a logical approach. However, more studies are needed to confirm whether preemptive inhaled corticosteroids are as, or more, effective than regular preventer therapy.

Life Cycle of Childhood Asthma: Prenatal, Infancy and Preschool, Childhood, and Adolescence

Asthma is a heterogeneous developmental disorder influenced by complex interactions between genetic susceptibility and exposures. Wheezing in infancy and early childhood is highly prevalent, with a substantial minority of children progressing to established asthma by school age, most of whom are atopic. Adolescence is a time of remission of symptoms with persistent lung function deficits. The transition to asthma in adulthood is not well understood.

Comparing Asthma Control Questionnaire (ACQ) and National Asthma Education and Prevention Program (NAEPP) asthma control criteria

BACKGROUND

Adequate assessment of control is critical to asthma management. The Asthma Control Questionnaire (ACQ) and the National Asthma Education and Prevention Program (NAEPP) criteria are commonly used measures of asthma control.

OBJECTIVE

To examine the associations between the ACQ and NAEPP criteria and compare the validity in association with lung function, asthma exacerbation, and quality of life.

METHODS

The ACQ and the NAEPP criteria were administered to 373 adolescents with asthma aged 12 to 20 years. The 2 measures correlated with forced expiratory volume in 1 second (FEV₁), asthma exacerbation (oral corticosteroid use, hospitalization, and emergency department [ED] use) in the past 12 months, and quality of life.

RESULTS

Agreement between the ACQ and NAEPP criteria was moderate (κ = 0.40-0.61). Neither of the 2 measures was a reliable predictor of FEV₁ less than 80% because of the high rate of false-positive results for the ACQ (68%) and low sensitivity for the NAEPP (49%). The NAEPP identified more cases of uncontrolled asthma (84.6%) than the ACQ (64.6%). The ACQ was a significant predictor of recent oral corticosteroid use, hospitalization, and ED visits (area under the curve = 0.66, 0.66, and 0.64, respectively; P < .001), as was NAEPP (area under the curve = 0.63, 0.66, and 0.61, respectively; P < .001). Both measures were significantly associated with quality of life, and the associations were particularly strong for the ACQ (r = -0.87 for symptom subscale, r = -0.76 for activity subscale, and r = -0.78 for emotional function subscale).

CONCLUSION

Neither the ACQ nor the NAEPP appears to reliably predict lung function, whereas both measures reasonably associate with acute asthma exacerbation. The ACQ may be the superior measure in gauging the psychosocial effect of asthma control given its particularly strong associations with quality of life.

TRIAL REGISTRATION

ClinicalTrials.gov Identifier: NCT02293499.

Clinical characterization of children with resistant airflow obstruction, a multicenter study

OBJECTIVE

To characterize a cohort of children with airflow limitation resistant to bronchodilator (BD) therapy.

METHODS

Pulmonary function tests performed in children 6-17 years of age at 15 centers in a clinical research consortium were screened for resistant airflow limitation, defined as a post-BD FEV₁ and/or an FEV₁/FVC less than the lower limits of normal. Demographic and clinical data were analyzed for associations with pulmonary function.

RESULTS

582 children were identified. Median age was 13 years (IQR: 11, 16), 60% were males; 62% were Caucasian, 28% were African-American; 19% were obese; 32% were born prematurely and 21% exposed to second hand smoke. Pulmonary diagnoses included asthma (93%), prior significant pneumonia (28%), and bronchiectasis (5%). 65% reported allergic rhinitis, and 11% chronic sinusitis. Subjects without a history of asthma had significantly lower post-BD FEV₁% predicted (p = 0.008). Subjects without allergic rhinitis had lower post-BD FEV₁% predicted (p = 0.003). Children with allergic rhinitis, male sex, obesity and Black race had better pulmonary function post-BD. There was lower pulmonary function in children after age 11 years without a history of allergic rhinitis, as compared to those with a history of allergic rhinitis.

CONCLUSIONS

The most prevalent diagnosis in children with BD-resistant airflow limitation is asthma. Allergic rhinitis and premature birth are common co-morbidities. Children without a history of asthma, as well as those with asthma but no allergic rhinitis, had lower pulmonary function. Children with BD-resistant airflow limitation may represent a sub-group of children with persistent obstruction and high risk for life-long airway disease.

Health Disparities Among Children with Asthma in the United States by Place of Residence

BACKGROUND

Children residing in poor-urban areas may have greater asthma morbidity. It is unclear whether this is due to individual characteristics such as race and ethnicity or place of residence.

OBJECTIVE

Assess indicators of control and treatment by residence.

METHODS

This was a cross-sectional analysis of children (aged 1-17 years) in the 2000-2014 Medical Expenditure Panel Survey (MEPS). Indicators of poor control included use of more than 3 canisters of short-acting beta agonist (SABA) in 3 months, asthma attack, and emergency department (ED) or inpatient (IP) visit during the year. Treatment measures included use of controller medications and a ratio of controller-to-total prescriptions of 0.7 or more.

RESULTS

There were 15,052 children with asthma in the MEPS 2000-2014 data, reflecting 8.4 million children in 2014. After controlling for covariates, children with asthma residing in poor-urban areas had lower odds of using controller medications (odds ratio [OR] = 0.77), having a controller-to-total ratio of 0.7 or more (OR = 0.75), and reporting an asthma attack (OR = 0.75) and higher odds of having an ED/IP visit (OR = 1.3) compared with those living elsewhere. Black race and Hispanic ethnicity were associated with greater odds of excessive SABA use (OR = 2.11) and ED/IP visits (OR = 2.03) and lower odds of controller-to-total ratio of 0.07 or more (OR = 0.50).

CONCLUSIONS

Poor-urban residence may be independently associated with asthma control and treatment even after controlling for individual characteristics such as race and ethnicity. Future research is needed to understand the sources of these geographic health disparities to more successfully target public health interventions.

Lung function trajectories from pre-school age to adulthood and their associations with early life factors: a retrospective analysis of three population-based birth cohort studies

BACKGROUND

Maximal lung function in early adulthood is an important determinant of mortality and COPD. We investigated whether distinct trajectories of lung function are present during childhood and whether these extend to adulthood and infancy.

METHODS

To ascertain trajectories of FEV₁, we studied two population-based birth cohorts (MAAS and ALSPAC) with repeat spirometry from childhood into early adulthood (1046 participants from 5-16 years and 1390 participants from 8-24 years). We used a third cohort (PIAF) with repeat lung function measures in infancy (V'_maxFRC) and childhood (FEV₁; 196 participants from 1 month to 18 years of age) to investigate whether these childhood trajectories extend from early life. We identified trajectories using latent profile modelling. We created an allele score to investigate genetic associations of trajectories, and constructed a multivariable model to identify their early-life predictors.

FINDINGS

We identified four childhood FEV₁ trajectories: persistently high, normal, below average, and persistently low. The persistently low trajectory (129 [5%] of 2436 participants) was associated with persistent wheezing and asthma throughout follow-up. In genetic analysis, compared with the normal trajectory, the pooled relative risk ratio per allele was 0·96 (95% CI 0·92-1·01; p=0·13) for persistently high, 1·01 (0·99-1·02; p=0·49) for below average, and 1·05 (0·98-1·13; p=0·13) for persistently low. Most children in the low V'_maxFRC trajectory in infancy did not progress to the low FEV₁ trajectory in childhood. Early-life factors associated with the persistently low trajectory included recurrent wheeze with severe wheezing exacerbations, early allergic sensitisation, and tobacco smoke exposure.

INTERPRETATION

Reduction of childhood smoke exposure and minimisation of the risk of early-life sensitisation and wheezing exacerbations might reduce the risk of diminished lung function in early adulthood.

FUNDING

None.

Exercise-induced bronchospasm in children and adolescents with allergic rhinitis by treadmill and hyperventilation challenges

BACKGROUND

Respiratory complaints after exercise are common in patients with rhinitis. Exercise-induced bronchospasm (EIB) may be one of the causes.

OBJECTIVES

To evaluate EIB prevalence in a group of children and adolescents with allergic rhinitis, to compare the treadmill running (TR) and eucapnic voluntary hyperventilation (EVH) challenge methods as diagnostic tools and to assess the association between respiratory complaints on exercise and EIB.

METHODS

Patients aged between 10 and 20 years were studied at the Pulmonology Department of the Hospital das Clínicas -UFPE- Recife, Brazil. The severity of symptoms of rhinitis and exercise-related respiratory complaints in the past year were evaluated. Challenges were performed in random sequence, no more than 72 h apart and followed international guidelines. Forced expiratory volume in the first second (FEV1) was determined before and 3, 5, 7, 10, 15 and 30 min after each challenge. A >10% reduction in FEV1 from baseline at two points after the challenge was considered sufficient to diagnose EIB.

RESULTS

Of the thirty-five subjects evaluated, thirteen (37%) showed EIB, six by both methods, three only after TR and four only after EVH (Coens' Kappa = 0.489). There was no association between respiratory complaints after exercise and EIB (p = 0.74).

CONCLUSION

A high prevalence of EIB was found in this population but only moderate agreement between the challenges used to diagnose EIB. Caution should be adopted when comparing these methods or interpreting their results interchangeably. There was no association between reported respiratory symptoms after exercise and EIB.

Impact of childhood wheezing on lung function in adulthood: A meta-analysis

BACKGROUND

A growing body of evidence shows that childhood wheezing may lead to recurrent or persistent symptoms in adulthood, such that persistent wheezing associated with lung function deficits often have their roots in the first few years of life.

OBJECTIVES

We summarized information from several prospective cohort studies following children with or without wheezing into adulthood, to estimate the effect of childhood wheezing on adulthood lung function.

METHODS

Medical literatures were searched in the Medline, PubMed, ScienceDirect, Web of Science and Embase databases up to October 31, 2016. The adulthood lung function was selected as primary outcome, and chronic obstructive pulmonary disease (COPD) prevalence was selected as secondary outcome. The meta-analysis was performed with the Stata Version 14.0. A random-effects model was applied to estimate standardized mean difference (SMD) of lung function, and relative risk (RR) of COPD.

RESULTS

Six articles enrolling 1141 and 1005 children with and without wheezing, respectively. Meta-analysis showed that childhood wheezing decreased adulthood lung function as compared with no-wheezing subjects (SMD = -0.365, 95% confidence interval (CI): -0.569~-0.161, P = 0.000). Subgroup analyses indicated that childhood atopic wheezing reduced adulthood FEV1/FVC and FEV1%pred when compared with no-wheezing subjects. In addition, childhood atopic wheezing was significantly associated with COPD prevalence (RR = 5.307, 95% CI:1.033~27.271, P = 0.046).

CONCLUSIONS

Our meta-analysis suggests that childhood wheezing may induce ongoing declined lung function that extends into adult life, as well as an increased risk of COPD prevalence when accompanied with atopy.

Grandmaternal smoking increases asthma risk in grandchildren: A nationwide Swedish cohort

BACKGROUND

There is growing interest in exposures prior to conception as possible risk factors for offspring asthma. Although partially supported by evidence from limited human studies, current evidence is inconsistent and based on recall of exposure status.

OBJECTIVE

We aimed to investigate grandmaternal smoking during pregnancy and the risk of asthma in grandchildren using prospectively collected population-based data.

METHODS

Information on grandmaternal and maternal smoking during pregnancy and grandchild use of asthma medications was collected from national Swedish registries. Associations between grandmaternal smoking during pregnancy (10-12 weeks) and asthma medication use in grandchildren were investigated using generalized estimating equations. Ages at which asthma medications were prescribed classified childhood asthma into never, early transient (0-3 years), late onset (3-6 years) and early persistent (0-3 and 3-6 years) phenotypes.

RESULTS

From 1982 to 1986, 44 583 grandmothers gave birth to 46 197 mothers, who gave birth to 66 271 grandchildren (born 1996-2010). Children aged 1-6 years had an increased asthma risk if their grandmothers had smoked during pregnancy, with a higher risk for more exposure (10+ cigs/d; adjusted OR 1.23; 1.17, 1.30). Maternal smoking did not modify this relationship.

CONCLUSIONS & CLINICAL RELEVANCE

Children had an increased risk of asthma in the first 6 years of life if their grandmothers smoked during early pregnancy, independent of maternal smoking. Importantly, this exhibited a dose-response relationship and was associated with a persistent childhood asthma phenotype. These findings support possible epigenetic transmission of risk from environmental exposures in previous generations.

The national burden of poorly controlled asthma, school absence and parental work loss among school-aged children in the United States

OBJECTIVE

The degree of poorly controlled asthma and its association with missed school days and parental missed work days is not well understood.

METHODS

This was a retrospective analysis of missed school days and missed work days for school-aged children (SAC; aged 6-17) and their caregivers in the nationally representative 2007-2013 Medical Expenditure Panel Survey (MEPS). Indicators of poor asthma control included: exacerbation in previous 12 months; use of >3 canisters of short-acting beta agonist (SABA) in 3 months; and annual asthma-specific (AS) Emergency Department (ED) or inpatient (IP) visits. Negative binomial regression was used for missed school days, and a Heckman two-step selection model was used for missed work days. All analyses controlled for sociodemographics and other covariates.

RESULTS

There were 44,320 SAC in MEPS, of whom 5,890 had asthma. SAC with asthma and an indicator of poor control missed more school days than SAC without asthma: exacerbation (1.8 times more; p < 0.001); >3 canisters SABA (2.7 times more; p < 0.001) and ED/IP visit (3.8 times more; p < 0.001). The parents/caregivers of SAC with asthma and an exacerbation missed 1.2 times more work days (p < 0.05), while those with SAC with asthma and an ED/IP visit missed 1.8 times more work days (p < 0.01) than the parents of SAC without asthma.

CONCLUSIONS

This study provides evidence of the significant national burden of poorly controlled asthma due to missed school and work days in the United States. More effective and creative asthma management strategies, with collaboration across clinical, community and school-based outreach, may help address this burden.

National Prevalence of Poor Asthma Control and Associated Outcomes Among School-Aged Children in the United States

BACKGROUND

The degree of asthma control among school-aged children (SAC) nationally is not well understood.

OBJECTIVE

The objective of this study was to characterize poor control among SAC (aged 6-17 years) in the United States.

METHODS

This was a retrospective analysis of the 2007-2013 Medical Expenditure Panel Survey. Indicators of poor control included exacerbation in previous year; use of >3 canisters of short-acting β-agonist (SABA) in 3 months; and asthma-specific (AS) emergency department (ED) or inpatient (IP) visits. Treatment indicators included daily controller medication and peak flow meter use. Negative binomial regression was used for health resource utilization (HRU); generalized linear models with log-link were used for health care expenditures.

RESULTS

There were 44,320 SAC, of whom 5,890 had asthma. The prevalence of poor control and treatment among SAC with asthma were as follows: exacerbation (59%), >3 canisters of SABA (4%), ED/IP visit (3%), daily controller (19%), peak flow (12%). In 2013, 3.4 million SAC had an asthma exacerbation and 200,000 had an AS ED/IP visit. SAC with asthma and an exacerbation had 18.9 times more annual AS ED visits (and 43.3 times more AS hospitalizations) than SAC with asthma but no exacerbation. SAC with asthma and an indicator of poor control incurred greater annual all-cause expenditures than SAC without asthma ($US 2015): $1,144 (exacerbation), $1,859 (≥3 canisters of SABA), and $3,063 (ED/IP visit). Use of daily controller medication was low even among SAC with poor control (27% to 61%).

CONCLUSION

Renewed and vigilant asthma management and treatment is necessary to mitigate the current and long-term public health effects and expenditures associated with poor asthma control.

Breastfeeding and perinatal exposure, and the risk of asthma and allergies

PURPOSE OF REVIEW

Exposures during the perinatal period, a phase of rapid development, may have a profound and sustained effect on disease risk. In particular, perinatal exposures may influence the development and maturation of the infant immune system and the risk of allergic disease. We aimed to summarize the current literature on perinatal exposures and the risk of asthma and allergic disease

RECENT FINDINGS

Increased risk of offspring wheeze or asthma was found for: maternal obesity and hypertension during pregnancy; febrile illness, gynaecological, and viral respiratory infections in pregnancy; exposure to bisphenol A and phthalates in pregnancy and childhood; exposure to smoking in utero; low birth weight; caesarean section and neonatal hyperbilirubinaemia. Reduced risk of offspring atopic eczema was found for hookworm infection in pregnancy and reduced risk of offspring wheeze was associated with increased pregnancy dietary intake of vitamin E and zinc. Higher levels of selenium in pregnancy were associated with less risk of asthma in genetically susceptible offspring. Early life pet ownership was associated with a decrease in atopic asthma but an increase in nonatopic asthma risk.

SUMMARY

A diverse range of exposures were associated with allergic disease risk, highlighting the susceptibility of children during the perinatal period. Clinicians should reinforce public health messages concerning maternal obesity, smoking, and breastfeeding. The infant gut microbiome is emerging as an important hypothesis, which may mediate the relationship between many perinatal exposures and allergic disease.

Childhood asthma is a risk factor for the development of chronic obstructive pulmonary disease

PURPOSE OF REVIEW

This review will catalog the many recent longitudinal studies that have investigated the relationship between asthma and lung function, or the persistence and trajectories of lung function deficits.

RECENT FINDINGS

Recent work has reported on 50-year follow-ups of some prominent population cohorts. A history of asthma confers a 10-30-fold risk of chronic obstructive pulmonary disease. Individuals reaching a reduced maximum growth of forced expiratory volume in 1 s in early adulthood are at risk for early or more severe chronic obstructive pulmonary disease (COPD).

SUMMARY

Taken together, there is a wealth of overlapping cohort studies of lung function, asthma and COPD. These show that asthma is associated with reduced lung function, which may start in infancy or prenatally, persists through childhood and adulthood and predisposes for early or more severe COPD.

Asthma phenotypes in childhood

PURPOSE OF REVIEW

This review describes the literature over the past 18 months that evaluated childhood asthma phenotypes, highlighting the key aspects of these studies, and comparing these studies to previous ones in this area.

RECENT FINDINGS

Recent studies on asthma phenotypes have identified new phenotypes on the basis of statistical analyses (using cluster analysis and latent class analysis methodology) and have evaluated the outcomes and associated risk factors of previously established early childhood asthma phenotypes that are based on asthma onset and patterns of wheezing illness. There have also been investigations focusing on immunologic, physiologic, and genetic correlates of various phenotypes, as well as identification of subphenotypes of severe childhood asthma.

SUMMARY

Childhood asthma remains a heterogeneous condition, and investigations into these various presentations, risk factors, and outcomes are important since they can offer therapeutic and prognostic relevance. Further investigation into the immunopathology and genetic basis underlying childhood phenotypes is important so therapy can be tailored accordingly.

Early smoke exposure is associated with asthma and lung function deficits in adolescents

OBJECTIVE

Early life tobacco smoke exposure may influence asthma, lung function and lung function growth into adolescence. We aimed to determine the associations between perinatal smoke exposure and asthma and lung function up to 18 years of age.

METHODS

We prospectively recorded perinatal parental smoking and measured respiratory outcomes at 12 and 18 years in the Melbourne Atopy Cohort Study (MACS), a longitudinal birth cohort. Multiple logistic regression was used to analyse the associations between perinatal smoke exposure and asthma at 12 (n = 370) and 18 years (n = 411). Multiple linear regression was used to investigate the relationship between perinatal smoking and: lung function (12 and 18 years) and lung function growth (between 12 and 18 years).

RESULTS

At 18 years, girls exposed to parental smoking during the perinatal period had increased odds of asthma (OR: 3.45, 95%CI: 1.36, 8.77), reduced pre-bronchodilator Forced expiratory volume in one-second (FEV₁) (-272 ml/s; -438, -107); FEV₁/ forced vital capacity (FVC) (-0.038; -0.065, -0.010); mid expiratory flow (MEF_25-75) (-430 ml/s; -798, -61), and reduced post-bronchodilator FEV₁/FVC (-0.028, -0.053, -0.004). No associations were found for boys (pre-bronchodilator FEV₁ 26ml/s; -202, 255; FEV₁/FVC 0.018; -0.013, 0.049).

CONCLUSIONS

Perinatal smoke may affect risk of asthma, reduce lung function and lung function growth in adolescence. Girls appear to be more susceptible than boys.

Asthma transition from childhood into adulthood

Asthma is the most prevalent chronic respiratory disease both in children and adults and resembles a complex syndrome rather than a single disease. Different methods have been developed to better characterise distinct asthma phenotypes in childhood and adulthood. In studies of adults, most phenotyping relies on biomaterials from the lower airways; however, this information is missing in paediatric studies because of restricted accessibility. Few patients show symptoms throughout childhood, adolescence, and adulthood. Risk factors for this might be genetics, family history of asthma and atopy, infections early in life, allergic diseases, and lung function deficits. In turn, a large proportion of children with asthma lose their symptoms during school age and adolescence. This improved prognosis, which might also reflect a better treatment response, is associated with being male and with milder and less allergic disease. Importantly, whether clinical remission of symptoms equals the disappearance of underlying pathology is unknown. In fact, airway hyper-responsiveness and airway inflammation might remain despite the absence of overt symptoms. Additionally, a new-onset of asthma symptoms is apparent in adulthood, especially in women and in the case of impaired lung function. However, many patients do not remember childhood symptoms, which might reflect relapse rather than true initiation. Both relapse and adult-onset of asthma symptoms have been associated with allergic disease and sensitisation in addition to airway hyper-responsiveness. Thus, asthma symptoms beginning in adults might have originated in childhood. Equivocally, persistence into, relapse, and new-onset of symptoms in adulthood have all been related to active smoking. However, underlying mechanisms for the associations remain unclear, and future asthma research should therefore integrate standardised molecular approaches in identical ways in both paediatric and adult populations and in longitudinal studies.

A systematic review of early life factors which adversely affect subsequent lung function

It has been known for many years that multiple early life factors can adversely affect lung function and future respiratory health. This is the first systematic review to attempt to analyse all these factors simultaneously. We adhered to strict a priori criteria for inclusion and exclusion of studies. The initial search yielded 29,351 citations of which 208 articles were reviewed in full and 25 were included in the review. This included 6 birth cohorts and 19 longitudinal population studies. The 25 studies reported the effect of 74 childhood factors (on their own or in combinations with other factors) on subsequent lung function reported as percent predicted forced expiration in one second (FEV₁). The childhood factors that were associated with a significant reduction in future FEV₁ could be grouped as: early infection, bronchial hyper-reactivity (BHR) / airway lability, a diagnosis of asthma, wheeze, family history of atopy or asthma, respiratory symptoms and prematurity / low birth weight. A complete mathematical model will only be possible if the raw data from all previous studies is made available. This highlights the need for increased cooperation between researchers and the need for international consensus about the outcome measures for future longitudinal studies.

Asthma phenotypes: the intriguing selective intervention with Montelukast

Asthma is a heterogeneous disease, usually characterized by chronic airway inflammation and a variable course associated with various underlying mechanisms that can differ between individuals. Patients with asthma can therefore exhibit different phenotypes, a term used to define the observable characteristics of an organism resulting from the interaction between its genetic makeup and the environment. The heterogeneity of asthma has received a large amount of attention in the last few years in order to better tailor treatment according to the different clinical and biological phenotypes of the disease. Specific asthma phenotypes may require an approach to treatment sometimes different from that recommended by current guidelines, so a personalized approach to asthma pharmacotherapy is recommended. Growing evidence suggests that leukotrienes play an important role in the pathogenesis of bronchial asthma. The mechanisms of action of leukotriene-receptor antagonists theoretically predict a good response in some asthma “phenotypes”.In this article we have performed an analysis of the recent literature (controlled clinical trials and real-life studies) about a possible selective intervention with Montelukast in specific asthma phenotypes.