Asthma from birth to age 23: incidence and relation to prior and concurrent atopic disease

Season of birth and atopic dermatitis in early infancy: results from the Japan Environment and Children's Study

BACKGROUND

Atopic dermatitis (AD) is reported to be more prevalent in children who were born in autumn than in spring. Here, we investigated how early the association between season of birth and eczema or AD can be observed in the postnatal period. We also examined whether specific prevalence outcomes for infant eczema and AD differed according to sex and maternal history of allergic disease in a large Japanese cohort.

METHODS

Using data of 81,615 infants from the Japan Environment and Children's Study, we examined the associations of birth month or season with four different outcomes-eczema at 1 month, 6 months, and 1 year of age and physician-diagnosed AD up to 1 year of age-using multiple logistic regression analysis. We also analyzed the effect of maternal history of allergic disease on these outcomes stratified by infant sex.

RESULTS

The risk of eczema at 1 month was highest in infants born in July. In contrast, infants born in autumn had higher risks of eczema at 6 months (adjusted odds ratio [aOR], 2.19; 95% confidence interval [CI], 2.10-2.30) and at 1 year (aOR, 1.08; 95% CI, 1.02-1.14) and of physician-diagnosed AD up to 1 year of age (aOR, 1.33; 95% CI, 1.20-1.47) compared with infants born in spring. Eczema and AD were more prevalent in infants with a maternal history of allergic disease, particularly boys.

CONCLUSIONS

Our findings suggest that the prevalence of AD is associated with the season of observation. Eczema is prevalent in infants born in autumn, and this phenomenon was observed in infants as young as 6 months old. The risk associated with being born in autumn was particularly clear in boys with a maternal history of allergic disease.

TRIAL REGISTRATION

UMIN000030786.

Different Characteristics and Clinical Outcomes between Early-Onset and Late-Onset Asthma: A Prospective Cohort Study

Late-onset asthma (LOA) differs from early-onset asthma (EOA) in terms of prognosis and the treatment response because it has a much worse prognosis and a poorer response to standard asthma treatment. This study sought to investigate the characteristics and clinical outcomes of asthma patients with phenotypes distinguished by age at onset and atopy status. We prospectively recruited patients with asthma who were registered in a pay-for-performance program operated by Taiwan’s National Health Insurance Administration (NHIA). These patients received regular outpatient treatment for at least 1 year at every outpatient clinic visit since 2019. Baseline characteristics and clinical outcomes were compared between patients with LOA (≥40 years) and those with EOA (<40 years). Of the consecutive 101 patients with asthma, 21 patients (20.7%) had EOA and 80 (79.3%) had LOA. In the 12-month period, patients with EOA had higher declines in forced expiratory volume in one second (FEV1; −2.1 ± 8.4 vs. 6.8 ± 13.1, % of predicted value, p = 0.037) and forced vital capacity (FVC; −4.6 ± 12.0 vs. 6.1 ± 13.6, % of predicted value, p = 0.023) than patients with LOA. Patients with nonatopic EOA had a significantly higher exacerbation rate at 12 months than patients with nonatopic LOA (50% vs. 11.8%, p = 0.012). Identification of different phenotypes of asthma is important in clinical practice because treatment responses may differ.

Characteristics of inpatients with atopic asthma in a tertiary center: Do age and gender have an influence?

Background: Several studies have demonstrated gender influence on asthma prevalence, being higher among males during early childhood. Little is known about the impact of gender and age on asthma exacerbation characteristics in pediatrics. This study aimed to determine the differences in acute asthma between males and females in three different age groups regarding perinatal characteristics of asthmatic patients, comorbidities, medication adherence, level of blood eosinophils, and pattern of hospitalization.Methods: The medical records of 130 pediatric patients with asthma, who presented to the emergency department at Jordan University hospital with asthma exacerbations, were retrospectively reviewed. Demographic information and clinical characteristics were collected.Results: The mean age of patients was 10.7±4.7 years. The age at diagnosis and gestational age were significantly higher in older children. Furthermore, younger children were significantly more likely to experience winter exacerbations and more emergency presentations. Male patients were considerably younger than their female counterparts and were diagnosed younger. In addition, male patients were more likely to have eosinophil levels higher than 3% than female patients.Conclusion: Gender plays a role in the development and outcome of asthma exacerbations at different ages of pediatrics. A better understanding of gender-based and age-based differences in asthma dictates a personalized approach to treatment.

Perimenstrual Asthma in Adolescents: A Shared Condition in Pediatric and Gynecological Endocrinology

Asthma is a frequent medical condition in adolescence. The worsening of the most common symptoms perimenstrually is defined as perimenstrual asthma (PMA). The cause of PMA remains unclear, but a role for hormonal milieu is plausible. Data on PMA in adolescents are limited, and its management is not fully established. We aimed to discuss the PMA phenomenon in young females from pathophysiology to preventive strategies, focusing on the relationship with the hormonal pattern. The fluctuation of estrogens at ovulation and before menstruation and the progesterone secretion during the luteal phase and its subsequent withdrawal seem to be the culprits, because the deterioration of asthma is cyclical during the luteal phase and/or during the first days of the menstrual cycle. Conventional asthma therapies are not always effective for PMA. Preventive strategies may include innovative hormonal contraception. Even a possible beneficial effect of other hormonal treatments, including estrogens, progestogens, and androgens, as well as leukotriene receptor antagonists and explorative approach using microbial-directed therapy, is considered. The underlying mechanisms, through which sex-hormone fluctuations influence asthma symptoms, represent a challenge in the clinical management of such a distressing condition. Further studies focused on young females are mandatory to promote adolescent health.

Sex Disparities in Asthma Development and Clinical Outcomes: Implications for Treatment Strategies

A gender-related disparity exists in asthma morbidity and mortality, which shifts at around puberty from a male predominance to a female predominance. This is clinically reflected in the fact that asthma that occurs in childhood (childhood-onset asthma) mainly affects boys, and that asthma that occurs in adulthood (adult-onset asthma) mainly affects women. Adult-onset asthma is often non-atopic, more severe, and associated with a poorer prognosis, thus posing a marked burden to women’s health and healthcare system. Many factors have been indicated to explain this gender-related disparity, including sociocultural and environmental factors as well as biological sex differences (genetic, pulmonary and immunological factors). It has long been suggested that sex hormones may be implicated in at least these biological sex differences. Overall, the evidence remains equivocal for the role of most sex hormones in asthma pathogenesis and clinical outcomes. Well-designed randomized clinical trials are required assessing the potential preventive or therapeutic effects of hormonal contraceptives on asthma in women, thereby helping to advance the evidence to inform future practice guidelines. The mechanisms underlying the role of sex hormones in asthma are complex, and our understanding is not yet complete. Additional mechanistic studies elucidating sex hormone signaling pathways and their interactions involved in the pathogenesis and clinical manifestations of asthma will help to identify potential sex hormone-driven asthma endotypes and novel therapeutic targets, providing the basis for a more personalized asthma management strategy.

UK Dental Medicines Advisory Service: questions asked by dentists - part 4: prescribing of high-strength fluoride toothpastes and use of fluoride varnishes in dental practice

The UK Dental Medicines Advisory Service (UKDMAS) provides advice to dentists and other dental healthcare professionals concerning the use of medicines and medical devices in dental prescribing, administering, or dispensing. The commonly asked questions posed to the UKDMAS concerning the prescribing of high-strength fluoride toothpastes and use of fluoride varnishes in dental practice are discussed with answers, supplemented by relevant information from clinicians. These include: the prescribing of high-strength fluoride toothpastes and application of fluoride varnish in particular patient groups; issues concerning the amounts of fluoride toothpaste that can be prescribed; regulations related to the supply of fluoride toothpastes by dental hygienists and therapists; and the constituents and selection of fluoride varnishes.

US Childhood Asthma Incidence Rate Patterns From the ECHO Consortium to Identify High-risk Groups for Primary Prevention

Importance

Asthma is the leading chronic illness in US children, but most descriptive epidemiological data are focused on prevalence.

Objective

To evaluate childhood asthma incidence rates across the nation by core demographic strata and parental history of asthma.

Design, Setting, and Participants

For this cohort study, a distributed meta-analysis was conducted within the Environmental Influences on Child Health Outcomes (ECHO) consortium for data collected from May 1, 1980, through March 31, 2018. Birth cohort data of children from 34 gestational weeks of age or older to 18 years of age from 31 cohorts in the ECHO consortium were included. Data were analyzed from June 14, 2018, to February 18, 2020.

Exposures

Caregiver report of physician-diagnosed asthma with age of diagnosis.

Main Outcome and Measures

Asthma incidence survival tables generated by each cohort were combined for each year of age using the Kaplan-Meier method. Age-specific incidence rates for each stratum and asthma incidence rate ratios by parental family history (FH), sex, and race/ethnicity were calculated.

Results

Of the 11 404 children (mean [SD] age, 10.0 [0.7] years; 5836 boys [51%]; 5909 White children [53%]) included in the primary analysis, 7326 children (64%) had no FH of asthma, 4078 (36%) had an FH of asthma, and 2494 (23%) were non-Hispanic Black children. Children with an FH had a nearly 2-fold higher incidence rate through the fourth year of life (incidence rate ratio [IRR], 1.94; 95% CI, 1.76-2.16) after which the rates converged with the non-FH group. Regardless of FH, asthma incidence rates among non-Hispanic Black children were markedly higher than those of non-Hispanic White children during the preschool years (IRR, 1.58; 95% CI, 1.31-1.86) with no FH at age 4 years and became lower than that of White children after age 9 to 10 years (IRR, 0.67; 95% CI, 0.50-0.89) with no FH. The rates for boys declined with age, whereas rates among girls were relatively steady across all ages, particularly among those without an FH of asthma.

Conclusions and Relevance

Analysis of these diverse birth cohorts suggests that asthma FH, as well as race/ethnicity and sex, were all associated with childhood asthma incidence rates. Black children had much higher incidences rates but only during the preschool years, irrespective of FH. To prevent asthma among children with an FH of asthma or among Black infants, results suggest that interventions should be developed to target early life.

Early pubertal maturation and risk of childhood asthma: A Mendelian randomization and longitudinal study

BACKGROUND

Studies on early puberty and incident asthma have reported inconsistent results and are mainly performed in females. In this longitudinal study, we investigated the causal relationship between pubertal maturation and asthma through Mendelian randomization (MR) and explored the joint effect of overweightness and early pubertal maturation on asthma.

METHODS

We used data from the Taiwan Children Health Study with longitudinal follow-ups of 2991 children aged 11-17 years. Six puberty-related single-nucleotide polymorphisms (combined into a weighted allelic score) were used to yield genetic instrumental variables for early puberty. Early pubertal maturation was defined as reaching a certain pubertal stage earlier than the median age for that stage. Incident asthma cases were calculated by excluding children with a history of asthma prior to that age.

RESULTS

The results of MR analysis revealed that early pubertal maturation was associated with active asthma (OR = 1.18; 95% CI: 1.08-1.28); this effect was significant in male children. Early pubertal maturation significantly increased the risk of incident asthma outcomes at 12 and 17 years of age in both sexes (hazard ratio = 2.15; 95% CI: 1.21-3.84). Taking non-overweight and non-early puberty children as the reference group, we observed a synergistic effect of overweightness and early pubertal maturation on asthma risk (OR = 1.08; 95% CI: 1.04-1.11) in children of both sexes.

CONCLUSIONS

Early screening and intervention for obesity are recommended to prevent future early pubertal onset and asthma occurrence.

Changes in DNA methylation from pre- to post-adolescence are associated with pubertal exposures

BACKGROUND

Adolescence is a period characterized by major biological development, which may be associated with changes in DNA methylation (DNA-M). However, it is unknown to what extent DNA-M varies from pre- to post-adolescence, whether the pattern of changes is different between females and males, and how adolescence-related factors are associated with changes in DNA-M.

METHODS

Genome-scale DNA-M at ages 10 and 18 years in whole blood of 325 subjects (n = 140 females) in the Isle of Wight (IOW) birth cohort was analyzed using Illumina Infinium arrays (450K and EPIC). Linear mixed models were used to examine DNA-M changes between pre- and post-adolescence and whether the changes were gender-specific. Adolescence-related factors and environmental exposure factors were assessed on their association with DNA-M changes. Replication of findings was attempted in the comparable Avon Longitudinal Study of Parents and Children (ALSPAC) cohort.

RESULTS

In the IOW cohort, after controlling for technical variation and cell compositions at both pre- and post-adolescence, 15,532 cytosine-phosphate-guanine (CpG) sites (of 400,825 CpGs, 3.88%) showed statistically significant DNA-M changes from pre-adolescence to post-adolescence invariant to gender (false discovery rate (FDR) = 0.05). Of these 15,532 CpGs, 10,212 CpGs (66%) were replicated in the ALSPAC cohort. Pathway analysis using Ingenuity Pathway Analysis (IPA) identified significant biological pathways related to growth and development of the reproductive system, emphasizing the importance of this period of transition on epigenetic state of genes. In addition, in IOW, we identified 1179 CpGs with gender-specific DNA-M changes. In the IOW cohort, body mass index (BMI) at age 10 years, age of growth spurt, nonsteroidal drugs use, and current smoking status showed statistically significant associations with DNA-M changes at 15 CpGs on 14 genes such as the AHRR gene. For BMI at age 10 years, the association was gender-specific. Findings on current smoking status were replicated in the ALSPAC cohort.

CONCLUSION

Adolescent transition is associated with changes in DNA-M at more than 15K CpGs. Identified pathways emphasize the importance of this period of transition on epigenetic state of genes relevant to cell growth and immune system development.

Sex-specific incidence of asthma, rhinitis and respiratory multimorbidity before and after puberty onset: individual participant meta-analysis of five birth cohorts collaborating in MeDALL

Introduction

To understand the puberty-related sex shift in the prevalence of asthma and rhinitis as single entities and as respiratory multimorbidities, we investigated if there is also a sex-specific and puberty-related pattern of their incidences.

Methods

We used harmonised questionnaire data from 18 451 participants in five prospective observational European birth cohorts within the collaborative MeDALL (Mechanisms of the Development of Allergy) project. Outcome definitions for IgE-associated and non-IgE-associated asthma, rhinitis and respiratory multimorbidity (first occurrence of coexisting asthma and rhinitis) were based on questionnaires and the presence of specific antibodies (IgE) against common allergens in serum. For each outcome, we used proportional hazard models with sex–puberty interaction terms and conducted a one-stage individual participant data meta-analysis.

Results

Girls had a lower risk of incident asthma (adjusted HR 0.67, 95% CI 0.61 to 0.74), rhinitis (0.73, 0.69 to 0.78) and respiratory multimorbidity (0.58, 0.51 to 0.66) before puberty compared with boys. After puberty onset, these incidences became more balanced across the sexes (asthma 0.84, 0.64 to 1.10; rhinitis 0.90, 0.80 to 1.02; respiratory multimorbidity 0.84, 0.63 to 1.13). The incidence sex shift was slightly more distinct for non-IgE-associated respiratory diseases (asthma 0.74, 0.63 to 0.87 before vs 1.23, 0.75 to 2.00 after puberty onset; rhinitis 0.88, 0.79 to 0.98 vs 1.20, 0.98 to 1.47; respiratory multimorbidity 0.66, 0.49 to 0.88 vs 0.96, 0.54 to 1.71) than for IgE-associated respiratory diseases.

Discussion

We found an incidence ‘sex shift’ in chronic respiratory diseases from a male predominance before puberty to a more sex-balanced incidence after puberty onset, which may partly explain the previously reported sex shift in prevalence. These differences need to be considered in public health to enable effective diagnoses and timely treatment in adolescent girls.

Asthma Induction During Development and Adult Lung Function, Behavior and Brain Gene Expression

In developing youth, allergic asthma is the most common chronic condition, with 9%–10% of youth affected. Asthma onset during childhood and adolescence is further associated with other health issues, particularly psychiatric conditions. To understand causal mechanisms by which developmental asthma may lead to altered behavior, brain and health trajectories, we developed a mouse model of developmental allergic asthma. In the current study, we tested for potential long-term effects of developmental asthma on adult lung function and behavior and brain gene expression associated with emotion and stress regulation. We manipulated airway inflammation (AI) and methacholine (MCH)-induced bronchospasm (resulting in labored breathing, LB) in young male and female BALB/cJ mice and measured adult outcomes 3 months after final asthma manipulations. Results indicated that allergen exposure, used to cause AI, and which ended on post-natal day 56 (P56), led to persistent lung AI, mucus buildup and gene expression related to allergic asthma 3 months after final allergen exposure. In addition, at this same age, early allergen exposure led to altered brain gene expression related to stress regulation (prefrontal corticotropin releasing hormone receptor 1, Crhr1 and hippocampal glucocorticoid receptor, GR) and serotonin function (brainstem serotonin transporter, SERT). On the other hand, LB events during development led to altered anxiety-related behavior. Importantly, sex and pre-asthma fear-related behavior (ultrasonic vocalization, USV rates) modulated these adult outcomes. Asthma that develops during childhood/adolescence may have long-term impacts on emotion and stress regulation mechanisms, and these influences may be moderated by sex and pre-asthma temperament.

Incidence of Lower Respiratory Tract Infections and Atopic Conditions in Boys and Young Male Adults: Royal College of General Practitioners Research and Surveillance Centre Annual Report 2015-2016

Background

The Royal College of General Practitioners Research and Surveillance Centre comprises more than 150 general practices, with a combined population of more than 1.5 million, contributing to UK and European public health surveillance and research.

Objective

The aim of this paper was to report gender differences in the presentation of infectious and respiratory conditions in children and young adults.

Methods

Disease incidence data were used to test the hypothesis that boys up to puberty present more with lower respiratory tract infection (LRTI) and asthma. Incidence rates were reported for infectious conditions in children and young adults by gender. We controlled for ethnicity, deprivation, and consultation rates. We report odds ratios (OR) with 95% CI, P values, and probability of presenting.

Results

Boys presented more with LRTI, largely due to acute bronchitis. The OR of males consulting was greater across the youngest 3 age bands (OR 1.59, 95% CI 1.35-1.87; OR 1.13, 95% CI 1.05-1.21; OR 1.20, 95% CI 1.09-1.32). Allergic rhinitis and asthma had a higher OR of presenting in boys aged 5 to 14 years (OR 1.52, 95% CI 1.37-1.68; OR 1.31, 95% CI 1.17-1.48). Upper respiratory tract infection (URTI) and urinary tract infection (UTI) had lower odds of presenting in boys, especially those older than 15 years. The probability of presenting showed different patterns for LRTI, URTI, and atopic conditions.

Conclusions

Boys younger than 15 years have greater odds of presenting with LRTI and atopic conditions, whereas girls may present more with URTI and UTI. These differences may provide insights into disease mechanisms and for health service planning.

Exacerbation risk and characterisation of the UK's asthma population from infants to old age

BACKGROUND

Few studies have examined the characteristics of a general asthma population; most have focused on more severe patients or severe exacerbations.

METHODS

This population-based cohort study, from April 2007 to September 2015, used linked primary and secondary care electronic healthcare records (Clinical Practice Research Datalink, Hospital Episode Statistics). Characteristics of four age cohorts, 'Under 5s', '5 to 17s', '18 to 54s', '55+', were described. Exacerbation risk factors, including asthma severity (measured by the British Thoracic Society (BTS) stepwise approach), were assessed using Poisson regression.

RESULTS

424 326 patients with current asthma were eligible (n, median follow-up: 'Under 5s'=17 320, 1 year; '5 to 17s'=82 707, 3.3 years; '18 to 54s'=210 724, 4 years; '55+'=113 575, 5.1 years). Over 60% of the total study population had mild asthma (BTS steps 1/2). There were differences between the cohort's characteristics, including by gender, disease severity and exacerbation pattern. The rate of exacerbations was highest in the oldest cohort and lowest in the '5 to 17s' cohort (rate per 10 person-years (95% CI), 'Under 5s'=4.27 (4.18 to 4.38), '5 to 17s'=1.48 (1.47 to 1.50), '18 to 54s'=3.22 (3.21 to 3.24), '55+'=9.40 (9.37 to 9.42)). In all cohorts, exacerbation rates increased with increasing asthma severity, after adjusting for confounders including gender, socioeconomic status, smoking, body mass index, atopy, rhinitis, gastro-oesophageal reflux, anxiety, depression and COPD.

CONCLUSION

The majority of UK patients with asthma had mild asthma and did not experience an exacerbation during follow-up. Patients aged ≥55 years had the lowest proportion with mild asthma and highest rate of exacerbations; the opposite was found in patients aged between 5 and 18 years.

Peri-adolescent asthma symptoms cause adult anxiety-related behavior and neurobiological processes in mice

Human and animal studies have shown that physical challenges and stressors during adolescence can have significant influences on behavioral and neurobiological development associated with internalizing disorders such as anxiety and depression. Given the prevalence of asthma during adolescence and increased rates of internalizing disorders in humans with asthma, we used a mouse model to test if and which symptoms of adolescent allergic asthma (airway inflammation or labored breathing) cause adult anxiety- and depression-related behavior and brain function. To mimic symptoms of allergic asthma in young BALB/cJ mice (postnatal days [P] 7-57; N=98), we induced lung inflammation with repeated intranasal administration of house dust mite extract (most common aeroallergen for humans) and bronchoconstriction with aerosolized methacholine (non-selective muscarinic receptor agonist). Three experimental groups, in addition to a control group, included: (1) "Airway inflammation only", allergen exposure 3 times/week, (2) "Labored breathing only", methacholine exposure once/week, and (3) "Airway inflammation+Labored breathing", allergen and methacholine exposure. Compared to controls, mice that experienced methacholine-induced labored breathing during adolescence displayed a ∼20% decrease in time on open arms of the elevated plus maze in early adulthood (P60), a ∼30% decrease in brainstem serotonin transporter (SERT) mRNA expression and a ∼50% increase in hippocampal serotonin receptor 1a (5Htr1a) and corticotropin releasing hormone receptor 1 (Crhr1) expression in adulthood (P75). This is the first evidence that experimentally-induced clinical symptoms of adolescent asthma alter adult anxiety-related behavior and brain function several weeks after completion of asthma manipulations.

Growth trajectories and asthma/rhinitis in children: a longitudinal study in Taiwan

Studies have reported the effect of body weight in early childhood on asthma. However, the effect of growth patterns during school age on asthma and rhinitis has yet to be explored. We sought to investigate whether various growth patterns predict incident asthma and rhinitis.We conducted a nationwide longitudinal study (Taiwan Children Health Study) in 14 Taiwanese communities. Body mass index (BMI) z-scores of 4422 children aged 6-11 years were collected annually and distinct growth trajectory classes were identified using a latent generalised mixture model. Pulmonary function and exhaled nitric oxide fraction (F_eNO) levels were also measured. Whether different growth trajectory classes predict incident asthma and rhinitis at age 12, 15 and 18 years was determined using a discrete time hazard model.Four growth trajectory classes were identified. Persistently overweight children exhibited significantly increased risks of asthma and rhinitis at age 12 years. Furthermore, being persistently overweight had a long-term effect on incident asthma (hazard ratio 2.47, 95% CI 1.18-5.12) and rhinitis (hazard ratio 1.44, 95% CI 1.12-1.84) in adolescence and early adulthood. Children in high BMI classes exhibited significantly lower pulmonary functions compared with normal growth children. F_eNO levels were lower in children in the high BMI classes and higher in children showing declining obesity compared with normal growth children.Persistently overweight children exhibited incident asthma and rhinitis in adolescence and early adulthood.

Sex-specific risk factors for childhood wheeze and longitudinal phenotypes of wheeze

BACKGROUND

Although sexual dimorphism in wheeze and asthma prevalence are well documented, sex-specific risk factors for wheeze and longitudinal wheeze phenotypes have not been well elucidated.

OBJECTIVE

By using a large prebirth cohort, this study aimed to identify sex-specific risk factors for wheeze from birth through midchildhood and identify distinct longitudinal wheeze phenotypes and the sex-specific risk factors associated with these phenotypes.

METHODS

Mothers reported child wheeze symptoms over the past year approximately yearly on 9 occasions starting at age 1 year. We identified sex-specific predictors of wheeze, wheeze phenotypes, and sex-specific predictors of these phenotypes by using generalized estimating equations, latent class mixed models, and multinomial logistic analysis, respectively.

RESULTS

A total of 1623 children had information on wheeze at 1 or more time points. Paternal asthma was a stronger predictor of ever wheezing in boys (odds ratio [OR], 2.15; 95% CI, 1.74-2.66) than in girls (OR, 1.53; 95% CI, 1.19-1.96; P for sex by paternal asthma interaction = .03), whereas being black or Hispanic, birth weight for gestational age z score, and breast-feeding duration had stronger associations among girls. We identified 3 longitudinal wheeze phenotypes: never/infrequent wheeze (74.1%), early transient wheeze (12.7%), and persistent wheeze (13.1%). Compared with never/infrequent wheeze, maternal asthma, infant bronchiolitis, and atopic dermatitis were associated with persistent wheeze in both sexes, but paternal asthma was associated with persistent wheeze in boys only (OR, 4.27; 95% CI, 2.33-7.83; P for sex by paternal asthma interaction = .02), whereas being black or Hispanic was a predictor for girls only.

CONCLUSION

We identified sex-specific predictors of wheeze and longitudinal wheeze patterns, which might have important prognostic value and allow for a more personalized approach to wheeze and asthma treatment.

Association between menarche and increased bronchial hyper-responsiveness during puberty in female children and adolescents

PURPOSE

Bronchial hyper-responsiveness (BHR) is a key feature of asthma. The degree of BHR in children may be altered by several factors. We evaluated the prevalence of BHR according to age and gender in pediatric and adolescent population and analyzed the associated factors for gender differences.

METHODS

Among the 2,067 subjects, methacholine challenge tests were performed in 1,820 children from one elementary and one middle school in Seoul, Korea. A total of 1,725 subjects between 6 and 14 years old were included in the analysis. The prevalence of BHR, defined as a provocative concentration that induced a 20% reduction of FEV₁ (PC₂₀ ) that was less than 8 mg/ml, was evaluated according to age and gender. Gender differences associated with BHR prevalence at each age were calculated and multiple logistic regression analyses were performed to identify factors associated with BHR by gender.

RESULTS

The prevalence of BHR (PC₂₀  ≤ 8 mg/ml) for each gender decreased with age (P < 0.001). Although the prevalence of BHR linearly decreased in males with age, females showed an increase after 11 years of age. BHR in males was associated with a younger age (aOR, 0.797; 95%CI, 0.678-0.925), a higher blood eosinophil counts (%) (aOR, 1.160; 95%CI, 1.047-1.284), atopy (aOR, 2.091; 95%CI, 1.003-4.359), and a lower FEV₁ /FVC ratio (aOR, 0.947; 95%CI, 0.901-0.995), and FEF_25-75% (aOR, 0.980; 95%CI, 0.961-0.999). In females, BHR was significantly associated with a younger age (aOR, 0.845; 95%CI, 0.747-0.957), lower FEV₁ (%) (aOR, 0.961; 95%CI, 0.938-0.984), and menarche (aOR, 3.674; 95%CI, 1.226-11.012).

CONCLUSION

BHR declined with age in the Korean pediatric population. A younger age and reduced lung function were common factors related to BHR in both genders. Additionally, atopy was related to BHR in males, whereas sexual maturation was related to BHR in females. These findings have important clinical implications for evaluating of childhood BHR and asthma related to gender. Pediatr Pulmonol. 2016;51:1040-1047. © 2016 Wiley Periodicals, Inc.

Risk of asthma exacerbation associated with nonsteroidal anti-inflammatory drugs in childhood asthma: A nationwide population-based cohort study in Taiwan

Patients allergic to aspirin or nonsteroidal anti-inflammatory drugs (NSAIDs) who develop respiratory reactions such as bronchospasm or asthma exacerbation have aspirin-induced asthma or NSAIDs-exacerbated respiratory disease. However, large-scale studies have not been conducted to investigate the risk of aspirin/NSAIDs exposure in children with asthma. Therefore, this study evaluated the relationship between aspirin/NSAIDs and the risk of asthma exacerbation in children with asthma.This retrospective cohort study was conducted using the data of 1 million random beneficiaries of the Taiwan National Health Insurance program between 1997 and 2012. Children aged ≦18 years diagnosed with asthma by physicians were enrolled. The study population was divided into the index group (concurrently using antiasthmatic agents and NSAIDs patients) and reference group (using antiasthmatic drugs alone), and the relative risks (RRs) of hospitalizations resulting from asthma exacerbation in both groups were estimated.The rate of asthma exacerbation was higher in the index group than the reference group, resulting in asthma-related hospitalizations (RR: 1.49, 95% confidence interval [CI]: 1.37-1.61; adjusted RR: 1.41, 95% CI: 1.30-1.53). Short-term aspirin, ibuprofen, and diclofenac use probably correlated with asthma exacerbation in children with asthma. No association between long-term aspirin, ibuprofen, and diclofenac consumption and the risk of asthma exacerbation was identified in this study.

The effect of respiratory tract infections on reported asthma symptoms

Background: Wheezing and chest tightness is associated with respiratory tract infections. Thus the occurrence of respiratory tract infections may infl uence the prevalence of asthma. Aims: To assess the strength of relation between two main symptoms of asthma and the prevalence of respiratory tract infections in children with and without asthma. Methods: The study population was 3,796 children, four years of age, whose parents had answered a questionnaire on respiratory symptoms and asthma. The prevalence of wheezing and chest tightness in the last 12 months and four weeks was estimated according to the occurrence of respiratory tract infections during the corresponding time periods; 95% confi dence intervals of the prevalence and the statistical signifi cance of the differences in the prevalence by using chi-square test were calculated. Results: The prevalence of wheezing and chest tightness was higher in children who had experienced respiratory tract infections than in those who had not. The prevalence of wheezing was 17.5% among children who had experienced bronchitis and 3.0% among children whom had not ( p<0.001). The prevalence of chest tightness in the last 12 months was 3.7% (95% CI 3.1- 4.1) among children without asthma and 59.3% (95% CI 53.4- 65.2) among children with asthma ( p<0.001). The prevalence of wheezing and chest tightness increased with increasing number of different types of respiratory tract infections among children without asthma ( p<0.001) and tended to be so among children with asthma. Conclusions: These findings have implications for the interpretation of results from epidemiological studies using respiratory symptoms as a health-related outcome of asthma.

Associations of wheezing phenotypes with late asthma outcomes in the Avon Longitudinal Study of Parents and Children: A population-based birth cohort

Background

Variable patterns of childhood wheezing might indicate differences in the cause and prognosis of respiratory illnesses. Better understanding of these patterns could facilitate identification of modifiable factors related to development of asthma.

Objectives

We characterized childhood wheezing phenotypes from infancy to adolescence and their associations with asthma outcomes.

Methods

Latent class analysis was used to derive phenotypes based on patterns of wheezing recorded at up to 14 time points from birth to 16½ years among 12,303 participants from the Avon Longitudinal Study of Parents and Children. Measures of lung function (FEV₁, forced vital capacity [FVC], and forced expiratory flow between 25% and 75% [FEF_25-75]) and fraction of exhaled nitric oxide (Feno) were made at 14 to 15 years of age.

Results

Six wheezing phenotypes were identified: never/infrequent, preschool-onset remitting, midchildhood-onset remitting, school age–onset persisting, late childhood–onset persisting, and continuous wheeze. The 3 persistent phenotypes were associated with bronchodilator reversibility of 12% or greater (BDR) from baseline (odds ratio [OR] range, 2.14-3.34), a Feno value of 35 ppb or greater (OR range, 3.82-6.24), and lung function decrements (mean range of differences: −0.22 to −0.27 SD units (SDU) for FEV₁/FVC ratio and −0.21 to −0.33 SDU for FEF_25-75) compared with never/infrequent wheeze. Midchildhood-onset (4½ years) remitting wheeze was associated with BDR (OR, 1.77; 95% CI, 1.11-2.82), a Feno value of 35 ppb or greater (OR, 1.72; 95% CI, 1.14-2.59), FEV₁/FVC ratio decrements (OR, −0.22 SDU; 95% CI, −0.36 to −0.08 SDU), and FEF_25-75 decrements (OR, −0.16 SDU; 95% CI, −0.30 to −0.01 SDU). Preschool-onset (18 months) remitting wheeze was only associated with FEV₁/FVC ratio decrements (OR, −0.15 SDU; 95% CI, −0.25 to −0.05 SDU) and FEF_25-75 decrements (OR, −0.14 SDU; 95% CI, −0.24 to −0.04 SDU). The persisting phenotypes showed evidence of sex stratification during adolescence.

Conclusions

Early childhood–onset wheezing that persists into adolescence represents the clearest target group for interventions to maximize lung function outcomes.

Sex and the lung: Observations, hypotheses, and future directions

Sex-related differences in a variety of lung diseases in infants and young children are reviewed, including respiratory distress syndrome, and chronic lung disease of prematurity, lower respiratory tract illnesses and wheezing, asthma, diffuse, and interstitial lung diseases, and cystic fibrosis. Differences in anatomy and physiology, such as airway size, airway muscle bulk, airway reactivity, airway tone, and cough reflexes may explain much of these sex differences. Better understanding of sex-related lung differences could help personalize respiratory treatment.

Change in the manifestations of asthma and asthma-related traits in childhood: a latent transition analysis

It is known that asthma is a heterogeneous entity whose manifestations vary with age. Our objective was to examine changes in the manifestation of asthma and asthma-related traits in childhood by defining empirically derived childhood asthma phenotypes and examining their transitions over time.To define the phenotypes we used data on respiratory symptoms, healthcare utilisation, medications, spirometry, airway hyperresponsiveness (AHR), exhaled nitric oxide concentration and atopy from a birth cohort recruited on the basis of having a first-degree relative with asthma. Data were acquired at ages 1.5-11.5 years and analysed using latent transition analysis.In a study population of 370 participants, we classified subjects into four phenotypes: 1) nonatopic, few symptoms (prevalence range from 1.5 to 5 years: 52-60%), 2) atopic, few symptoms (3-21%), 3) nonatopic, asthma and rhinitis symptoms (13-35%), and 4) atopic, asthma and rhinitis symptoms (2-14%) in early childhood; and 1) nonatopic, no respiratory disease (prevalence range from 8 to 11.5 years: 41-46%), 2) atopic, no respiratory disease (23-33%), 3) nonatopic, asthma symptoms, no AHR or airway inflammation (8-12%) and 4) atopic asthma (19%) in mid-childhood. Transitioning between phenotypes was common in early childhood, but less common in later childhood.This analysis represents the first attempt to incorporate longitudinal patterns of several manifestations of asthma into a single model to simultaneously define phenotypes and examine their transitions over time. It provides quantitative support for the view that asthma is a heterogeneous entity, and that some children with wheeze and other respiratory symptoms in early life progress to asthma in mid-childhood, while others become asymptomatic.

Gender- and age-specific risk factors for wheeze from birth through adolescence

BACKGROUND AND OBJECTIVE

Cross-sectional gender differences in wheeze are well documented, but few studies have examined the gender-specific risk factors for wheeze longitudinally. This study aims to identify gender- and age-specific risk factors for wheeze from birth through adolescence.

METHODS

The incidence of wheeze was ascertained every 6 months through age 14 years in a birth cohort consisting of 499 children with a parental history of atopy. Gender- and age-specific risk factors were identified through generalized estimating equations.

RESULTS

A total of 454 (91.0%) and 351 (70.3%) children were followed past age 7 and 13 years, respectively. Maternal asthma was a risk factor for wheeze in girls (OR = 2.05, 95% CI 1.44-2.91, P < 0.0001) and boys (OR = 1.79, 1.29-2.48, P = 0.0004) and had a similar effect on wheeze throughout the ages. Paternal asthma (OR = 1.83, 1.38-2.57, P = 0.0005) and infant bronchiolitis (OR = 2.15, 1.47-3.14, P < 0.0001) were risk factors for boys only, with similar effects throughout the ages.

CONCLUSION

Using a prospective cohort, we identified gender- and age-specific risk factors for wheeze. The identification of gender-specific early life risk factors may allow for timely interventions and a more personalized approach to the treatment of asthma.

Environmental risk factors related to the incidence of wheeze and asthma in adolescence

BACKGROUND

Asthma is common among adolescents, but there are few population-based studies on the risk factors for incident asthma and wheeze at this age group.

OBJECTIVE

To study risk factors for incident asthma and wheeze in adolescence.

METHOD

Within the Obstructive Lung Disease In Northern Sweden (OLIN) studies, a cohort of 3430 school children (age 7-8 year) was recruited in 1996. In the present study, this cohort was followed from age 12-19 year. At baseline (age 12 year), 3151 participated and skin prick tests (SPT) were performed. The cohort was resurveyed annually, and risk factors for the cumulative incidence of asthma and wheeze from age 12-19 year were analysed using multivariate Cox regression.

RESULTS

Female sex (wheeze: HR 1.4 95%CI 1.2-1.6; asthma: HR 1.8 95%CI 1.2-2.5) and a positive SPT to cat, dog or horse at baseline (wheeze: HR 1.6 95%CI 1.2-2.1; asthma: HR 2.3 95%CI 1.4-4.0) were significantly associated with the cumulative incidence of wheeze and asthma. Increasing numbers of siblings were inversely related to the incidence of wheeze (HR 0.9 95%CI 0.8-0.97) and asthma (HR 0.8 95%CI 0.7-0.97). Parental asthma was related to the incidence of asthma (HR 1.8 95%CI 1.2-2.6) while ever smoking (HR 2.0 95%CI 1.6-2.4) and house dampness (HR 1.3 95%CI 1.1-1.6) were risk factors for the incidence of wheeze. Maternal ETS exposure increased the risk of incident asthma in non-sensitized subjects (HR 1.9 95%CI 1.0-3.7).

CONCLUSION AND CLINICAL RELEVANCE

Several environmental risk factors related to the incidence of asthma and wheeze in adolescence were identified and may be possible targets for intervention and prevention.

Birth weight and asthma incidence by asthma phenotype pattern in a racially diverse cohort followed through adolescence

OBJECTIVE

Low birth weight (LBW) has been shown to be an independent risk factor for asthma. We hypothesized that LBW would have its greatest impact on early onset disease.

METHODS

A racially diverse cohort of children born from 1983 to 1985 at two hospitals, one urban and one suburban in the same metropolitan area, and oversampled for babies weighing ≤2500 g, was identified retrospectively when the children were 6 years of age and followed periodically. At the age 17 years study visit, cohort members and their parent/guardians were separately interviewed face-to-face regarding the subject's history of asthma using the standardized ISAAC questionnaire. We measured the cumulative incidence of asthma from birth through adolescence defined by age of diagnosis and persistence/remittance.

RESULTS

Six-hundred and eighty teens (82.6% of the original cohort) were included in the analyses, 387 with LBW and 293 of normal birth weight. The prevalence of physician-diagnosed "Current Asthma" was associated with LBW (p = 0.003 for trend), with patterns stronger in males and whites. LBW was associated most strongly with Late Onset Persistent asthma (current asthma that was diagnosed after 8 years); p for trend 0.032. This trend was again most evident in males and whites. None of the asthma categories classified as "remittent" were statistically associated with LBW.

CONCLUSIONS

LBW was not associated with diagnosed asthma that remitted before age 17 years. LBW was associated with asthma diagnosis in mid-childhood that persisted through adolescence, suggesting that the asthmagenic effects of LBW can become evident post the early years of childhood and persist into adulthood.

What factors are associated with the prevalence of atopic symptoms amongst adolescents in Greater Manchester?

INTRODUCTION

Atopy commonly manifests itself as atopic diseases (ADs), namely asthma, eczema and hay fever. The prevalence of AD is rising worldwide, and it is widely accepted as a major public health issue, due to the significant burden of AD on health care systems.

METHOD

Data were obtained from the youth survey of the European Urban Health Indicator System 2 project. The study participants were students aged 14-16 years from Greater Manchester. The main outcomes measured were the prevalence of atopic symptoms and the factors associated with the development of atopy.

RESULTS

Of the sample studied, 70% reported having had an AD during their lifetime. The lifetime prevalence of ever having asthma, eczema or hay fever was 33.4%, 28.1% and 49.0%, respectively. Gender, family affluence, body mass index, diet, smoking and worrying were all significantly associated with atopic symptoms. Smoking was the only variable to be significantly associated with all three ADs. Season of birth and pollution were not shown to be associated with atopic symptoms.

CONCLUSION

This study demonstrates that the prevalence of AD in Greater Manchester was high amongst adolescents. Several environmental, demographic and social factors were found to be significantly associated with the development of atopic symptoms. This study provides a baseline for future studies to further investigate the factors that are associated with AD and allow for the implementation of preventative public health policy.

Hormonal factors and incident asthma and allergic rhinitis during puberty in girls

BACKGROUND

Accumulating evidence is indicating that hormonal factors play a role in new-onset allergic rhinitis and asthma after puberty.

OBJECTIVE

To determine whether age at menarche and use of hormonal contraceptives predict new-onset allergic rhinitis and asthma after puberty in young German women.

METHODS

A prospective community-based cohort study followed 1,191 girls 9 to 11 years old to early adulthood (19-24 years old). Self-administrated questionnaires concerning age at menarche, use of hormonal contraceptives, and status and age at onset of physician-diagnosed allergic rhinitis and asthma were collected at 16 to 18 and 19 to 24 years of age. Logistic regression models were used to analyze the incidence of asthma and allergic rhinitis after puberty and pooled estimates were obtained from the final model.

RESULTS

Eleven percent of girls developed allergic rhinitis after menarche and 3% reported new-onset asthma. Late menarche (>13 years of age) was statistically significantly inversely related to allergic rhinitis (adjusted odds ratio [OR] 0.32, 95% confidence interval [CI] 0.14-0.74) but did not reach the level of statistical significance for asthma (OR 0.32, 95% CI 0.07-1.42). Use of hormonal contraceptives was inversely associated with new-onset allergic rhinitis (OR 0.14, 95% CI 0.08-0.23) and asthma (OR 0.27, 95% CI 0.12-0.58) after puberty.

CONCLUSION

This study shows that girls with late onset of menarche are less likely to develop allergic rhinitis after puberty compared with those who have menarche at an average age. These findings also suggest that, in addition to endogenous hormones, hormonal contraceptives play a role and might protect young women from allergies and asthma.

Natural progression of childhood asthma symptoms and strong influence of sex and puberty

RATIONALE

Asthma prevalence, onset, remission and relapse, and healthcare use have been intensively studied. However, asthma symptom progression through childhood and adolescence has not been well studied, in part due to the challenges in obtaining consistent and robust long-term follow-up data on a large series of subjects with asthma.

OBJECTIVES

To use the asthma diary symptom data of the Childhood Asthma Management Program placebo group (5 yr, 418 subjects, and total 564,518 records) to establish sex-specific high-resolution time courses of the natural progression of asthma symptoms through childhood and adolescence.

METHODS

We used the asthma diary symptom code as a measure of daily disease severity. Annual records of Tanner stage were used to determine the influence of puberty on severity. A data alignment technique was used to derive 13-year time courses of mean symptoms and mean Tanner stage.

MEASUREMENTS AND MAIN RESULTS

Data analyses showed three age- and sex-related phases of asthma symptom progression: Phase 1 (ages 5 and 6 yr)-greater severity in boys; Phase 2 (ages 7 to 9 yr)-no sex difference in severity; and Phase 3 (age 10-17 yr)-greater severity in girls. The continuous decline of symptoms in both sexes stops abruptly at the onset of puberty.

CONCLUSIONS

The severity of asthma symptoms varies through childhood and adolescence, and patterns differ by sex. Puberty has a strong influence on symptom progression in both sexes. Progression of symptoms is a distinct aspect of asthma epidemiology.

Joint incidence of asthma and rhinitis in macedonia

The concept of "united airways disease", based on many similar features and mutual interactions in the pathogenesis of asthma (A) and rhinitis (R), has led to an integral approach to their management. We conducted this study to determine the quantity of the problem of joint incidence of A and R in R. Macedonia, and, perhaps to obtain information on a potential causative effect of the two diseases. Three hundred eighty six patients, who presented with wheezing and/or upper respiratory symptoms at the Pulmology and Allergy Clinic, Skopje, were included during a period of 48 months. The presence of bronchial hyperreactivity - BHR (positive histamine challenge), atopy (prick test to seasonal or perennial inhaled allergens), rhinitis symptoms (such as nasal secretion and obstruction) and X-ray of paranasal sinuses was registered by a specially designed questionnaire. R was diagnosed in 106 of the subjects (27.5%), and A in 280 (72.5%). Among the patients with A, co-incidence with R was found in 219 (76.5%). Including X-ray of paranasal sinuses to the diagnostic protocol increased this percentage to over 90% (256 patients). From the 219 patients with A and R together, 127 (57.99%) had positive atopy. On the other hand, 19 (18.0%) of the rhinitis-only patients had positive BHR without asthma symptoms. The follow up of the rhinitis patients with positive BHR revealed 4 patiets who developed asthma within 36 months, but this was also the case with 2 of the subjects with R and negative BHR. In conclusion, the co-incidence of A and R in our material is 78.21%, or 91.4% (including sinusitis); a greater co-existence of A and R is found in atopic patients. The patients with allergic R are at high risk for developing A and should be monitored in the future and the R symptoms should be adequately treated in order to minimize the risk for developing asthma.

Factors associated with atopy in toddlers: a case-control study

In this case-control study the association between the approaches used to feed infants, together with known family and environmental factors, and the occurrence of atopic illness in toddlers between the ages of 4 months to 3 years in Hong Kong was examined. A total of 206 subjects were recruited from April to June of 2014. The results obtained by binary logistic regression indicated that atopy is associated with boys (OR 2.072, CI 1.089-3.941), the maternal use of antibiotics in utero or while breast feeding (OR 2.276, CI 1.151-4.504), the later commencement of mixed feeding (OR 2.497, CI 1.025-6.082), breast feeding exclusively for 3 months (OR 1.972, CI 1.009-3.857), and having a mother who was diagnosed with eczema (OR 4.510, CI 1.764-11.530). Although an exclusive reliance on breast feeding has been shown to be predictive of atopy among toddlers, the positive qualities of breast milk cannot be ignored. A further study of the contents and nutritional values of breast milk is warranted.

Elucidation of pathways driving asthma pathogenesis: development of a systems-level analytic strategy

Asthma is a genetically complex, chronic lung disease defined clinically as episodic airflow limitation and breathlessness that is at least partially reversible, either spontaneously or in response to therapy. Whereas asthma was rare in the late 1800s and early 1900s, the marked increase in its incidence and prevalence since the 1960s points to substantial gene × environment interactions occurring over a period of years, but these interactions are very poorly understood (1-6). It is widely believed that the majority of asthma begins during childhood and manifests first as intermittent wheeze. However, wheeze is also very common in infancy and only a subset of wheezy children progress to persistent asthma for reasons that are largely obscure. Here, we review the current literature regarding causal pathways leading to early asthma development and chronicity. Given the complex interactions of many risk factors over time eventually leading to apparently multiple asthma phenotypes, we suggest that deeply phenotyped cohort studies combined with sophisticated network models will be required to derive the next generation of biological and clinical insights in asthma pathogenesis.

Exercise-induced wheezing among Japanese pre-school children and pupils

BACKGROUND

Exercise-induced wheezing (EIW) may be a symptom of asthma and is a predictor of exercise-induced bronchoconstriction, transient narrowing of the lower airway following exercise in the presence or absence of diagnosed asthma. Population-based studies with a large sample of EIW in relation to age, sex, current asthma severity and medication usage have been sparse.

METHODS

International Study of Asthma and Allergies in Childhood questionnaires were distributed at 885 nurseries, 535 primary schools, 321 junior high schools and 190 high schools, respectively, across Japan, and the corresponding data on 46,597, 41,216, 45,960 and 51,104 children were analyzed.

RESULTS

Prevalence of EIW was 4.8, 4.7, 17.9 and 15.4% for each of the four educational facility types, respectively. Among 24,103 current asthmatics, 20.9, 28.7, 76.1 and 73.6% of subjects for the 4 educational facility groups reported to have experienced EIW, respectively. Severity of current asthma was associated with the risk of EIW; odds ratio (95% confidence interval) of children with asthma attack every day for having EIW once a week or more, using intermittent asthmatics as reference group, were 24.48 (19.33 to 31.01) adjusted for other covariates. Among current asthmatic kindergartners, increase in risk for EIW due to ascending severity of current asthma was mitigated by daily use of leukotriene receptor antagonist (p for interaction = 0.071).

CONCLUSIONS

EIW was not rare among current asthmatic children. An increased risk for EIW was in accordance with increasing severity of current asthma and this relation was mitigated with leukotriene receptor antagonist daily use among kindergartners.

Relevance of allergy in adult asthma

Recent studies on asthma have demonstrated multiple phenotypes, based on the clinical characteristics of the disease. With the current interest in personalized medicine, the question arises whether the presence of allergic sensitization has any relevance for these phenotypes and the management of asthma. This review will examine the current knowledge of asthma phenotypes and the impact of atopy on asthma diagnosis and severity in adults. In addition, this review will address whether therapies targeted at the atopic axis help improve asthma outcomes, including lung function indices and exacerbations.

Age at menarche and risk of asthma: systematic review and meta-analysis

BACKGROUND

Several studies have suggested a relationship between the age at menarche and risk of asthma development.

OBJECTIVE

To conduct a systematic review and meta-analysis of the relationship between the age at menarche and the risk of asthma.

METHODS

This systematic review and meta-analysis was performed in accordance with the Preferred Reporting Items for Systematic Reviews and Meta-analyses (PRISMA). A pre specified literature search strategy was used to identify studies of potential relevance and independent reviews were carried out by two authors. Raw data was pooled using the software package RevMan to calculate summary odds ratios. The risk of publication bias was assessed graphically by using a funnel plot and the robustness of the overall estimate obtained was assessed by using sensitivity analyses.

RESULTS

The searches identified 61 potentially relevant articles of which seven articles, with a total of 22,859 subjects, matched the inclusion criteria for the meta-analysis. Pooling of the seven studies showed that girls with early menarche (<12 years) had an increased risk of asthma relative to girls with late menarche; random effects odds ratio = 1.37 (1.15-1.64), (p = 0.0005). Substantial heterogeneity was revealed (I(2) = 55%). Sensitivity analysis showed that the risk estimate was not markedly changed when excluding any of the studies. The funnel plot did not indicate publication bias.

CONCLUSIONS

Early menarche appears to be associated with increased risk of asthma. Hormonal, immunological, genetic and environmental factors may act in a developmental context to explain this relationship. Future studies are warranted to further determine the mechanisms responsible for this observation.

The cystic fibrosis gender gap: potential roles of estrogen

Cystic fibrosis (CF) is a complex, multi-system, autosomal recessive disease predominantly affecting Caucasians that leads to vigorous airway inflammation and chronic respiratory infection, commonly with Pseudomonas aeruginosa. A variety of factors significantly modify the progression and severity of CF lung disease and the timing of the resulting mortality. We summarize here data indicating that there is in CF a female disadvantage in survival and morbidity, called the "CF gender gap". Although controversy exists regarding the nature and relative importance of the various contributing mechanisms involved, gender affects the progression of CF disease with respect to lung infection, decline in pulmonary function and nutritional status. These interrelated factors in turn have a negative impact on survival. This review will emphasize the increasing evidence that suggest a role for the effects of gender, and particularly the female sex hormone estrogen, on infection, inflammation and transepithelial ion transport, all major determinants of CF lung disease. Future elucidation of the pathophysiology of hormonal aggravation of CF lung disease may pave the way for novel therapeutic interventions. This, combined with the magnitude of the gender gap in CF mortality, strongly suggests that further work in this field is well justified.

Adult-onset asthma becomes the dominant phenotype among women by age 40 years. the longitudinal CARDIA study

RATIONALE

Although asthma is usually considered to originate in childhood, adult-onset disease is being increasingly reported.

OBJECTIVES

To contrast the proportion and natural history of adult-onset versus pediatric-onset asthma in a community-based cohort. We hypothesized that asthma in women is predominantly of adult onset rather than of pediatric onset.

METHODS

This study used data from the Coronary Artery Risk Development in Young Adults (CARDIA) cohort in the United States over a 25-year period. Adult- and pediatric-onset asthma phenotypes were studied, as defined by age at onset of 18 years or older. Subjects with asthma were categorized by sex, obesity, atopy, smoking, and race by mean age/examination year, using a three-way analysis of covariance model. Natural history of disease was examined using probabilities derived from a Markov chain model.

MEASUREMENTS AND MAIN RESULTS

Asthma of adult onset became the dominant (i.e., exceeded 50%) phenotype in women by age 40 years. The age by which adult-onset asthma became the dominant phenotype was further lowered for obese, nonatopic, ever-smoking, or white women. The prevalence trend with increasing time for adult-onset disease was greater among subjects with nonatopic than atopic asthma among both sexes. Furthermore, adult-onset asthma had remarkable sex-related differences in risk factors. In both sexes, the quiescent state for adult-onset asthma was less frequent and also "less stable" over time than for pediatric-onset asthma.

CONCLUSIONS

Using a large national cohort, this study challenges the dictum that most asthma in adults originates in childhood. Studies of the differences between pediatric- and adult-onset asthma may provide greater insight into the phenotypic heterogeneity of asthma.

Epidemiology of Respiratory Allergies and Asthma

Asthma has puzzled and confused physicians from the time of Hippocrates to the present day. The word “asthma” comes from a Greek word meaning “panting” (Keeney 1964), but reference to asthma can also be found in ancient Egyptian, Hebrew, and Indian medical writings (Ellul-Micallef 1976; Unger and Harris 1974). There were clear observations of patients experiencing attacks of asthma in the second century and evidence of disordered anatomy in the lung as far back as the seventeenth century (Dring et al. 1689).

Effects of puberty on cystic fibrosis related pulmonary exacerbations in women versus men

BACKGROUND

Epidemiologic data from studies of airway diseases, such as asthma, chronic obstructive pulmonary disease, and cystic fibrosis indicate a gender disparity where women have worse outcomes. The explanation for this is largely unknown. We hypothesize that female sex hormones play a role in this gender disparity, predisposing women to more exacerbations and decreased lung function post-puberty.

OBJECTIVE

In Cystic Fibrosis, to determine if puberty marks a point of increasing exacerbations and decreasing lung function in women relative to men.

METHODS

Using the United States Cystic Fibrosis Foundation Patient Registry, we used linear regression to compare lung function and rate of pulmonary exacerbations in men versus women before and after puberty.

RESULTS

Of 5,137 subjects who met inclusion criteria, 2,689 were male and 2,448 were female. Average age of puberty was found to be 13.2 ± 2.2 years in men and 11.2 ± 2.0 years of age in women. Percent predicted FEV1 pre- and post-puberty were no different between males versus females (P = 0.44 pre-puberty and P = 0.16 post-puberty). In contrast, women had a significantly higher rate of pulmonary exacerbations post-puberty than men (1.17 ± 1.35 exacerbations per year in women versus 0.95 ± 1.27 in men; P < 0.001) despite controlling for morphometrics, co-morbidities, and microbiologic variables.

CONCLUSION

After puberty, the rate of pulmonary exacerbations increased in adolescent women relative to men with cystic fibrosis, supporting a role for sex hormones in the disease process. Further understanding of the mechanisms that modulate sex hormone receptors in airway disease may serve as future targets for therapy.

Remission and persistence of asthma followed from 7 to 19 years of age

BACKGROUND AND OBJECTIVE

To date, a limited number of population-based studies have prospectively evaluated the remission of childhood asthma. This work was intended to study the remission and persistence of childhood asthma and related factors.

METHODS

In 1996, a questionnaire was distributed to the parents of all children aged 7 to 8 years in 3 municipalities in northern Sweden, and 3430 (97%) participated. After a validation study, 248 children were identified as having asthma; these children were reassessed annually until age 19 years when 205 (83%) remained. During the follow-up period lung function, bronchial challenge testing, and skin prick tests were performed. Remission was defined as no use of asthma medication and no wheeze during the past 12 months as reported at endpoint and in the 2 annual surveys preceding endpoint (ie, for ≥ 3 years).

RESULTS

At age 19 years, 21% were in remission, 38% had periodic asthma, and 41% persistent asthma. Remission was more common among boys. Sensitization to furred animals and a more severe asthma (asthma score ≥ 2) at age 7 to 8 years were both inversely associated with remission, odds ratio 0.14 (95% confidence interval 0.04-0.55) and 0.19 (0.07-0.54), respectively. Among children with these 2 characteristics, 82% had persistent asthma during adolescence. Asthma heredity, damp housing, rural living, and smoking were not associated with remission.

CONCLUSIONS

The probability of remission of childhood asthma from age 7- to 8-years to age 19 years was largely determined by sensitization status, particularly sensitization to animals, asthma severity, and female gender, factors all inversely related to remission.

The association of asthma with BMI and menarche in the 1958 British Birth Cohort

BACKGROUND

Obesity and early menarche have been associated with asthma. In this report, we assess the association of asthma with BMI and with changes in BMI from childhood to early adulthood. In addition, we determine if, in girls, any observed association of asthma with menarche can be explained by BMI.

METHODS

In a large national birth cohort, the associations of asthma at age 7, 11, 16 and 33 years with BMI, and of, asthma at age 33 years with changes in BMI from age 7 to age 33 years was assessed using logistic and mixed effects models as appropriate. Associations of asthma with age of menarche in girls were similarly assessed with and without adjustment for BMI.

RESULTS

Information on asthma, BMI, onset of menarche and confounders at all assessments was available for 1968 girls and 2223 boys. Obesity was relatively uncommon (<2%) in childhood. Overweight (BMI 25+) girls had more asthma. Girls with early menarche were more likely to be overweight. At age 11 years, asthma was associated with early menarche (OR = 1.70, 95% CI 1.17-2.47, after adjustment for BMI OR = 1.60, 95% CI 1.10-2.34). Across all ages, asthma was significantly associated with BMI (OR = 1.50, 95% CI 1.18-1.90) but not with early menarche (OR = 1.24, 95% CI 0.95-1.63).

CONCLUSION

Asthma is more common in overweight girls. Early menarche is more common in overweight girls but this does not explain its association with asthma at age 11 years. Early menarche is not a risk factor for asthma at age 33 years in this cohort.

The effect of oral contraceptives on current wheezing in young women

BACKGROUND

Emerging evidence suggests that sex steroid hormones may influence respiratory symptoms. The existing literature about the role of oral contraceptive pill (OCP) on respiratory disease is scarce and conflicting especially during the adolescent period. In this study, we aimed to investigate the effect of OCPs on current wheezing among adolescents and young adults.

METHODS

A questionnaire was administered face-to-face to adolescents and young women by a physician. The questionnaire included ISAAC survey-comprised questions on ever wheezing, current wheezing, allergic diseases, smoking history (active or passive), and family history of allergic diseases and questions on OCP usage status. The effect of OCPs on wheezing was evaluated by logistic regression analysis.

RESULTS

A total of 487 subjects aged between 11.3 and 25.6years participated in the study and 196 (40.2%) reported that they had used OCPs. 7.4% of the participants had physician-diagnosed asthma and 10.3% of them were active smokers. It was detected that OCPs were associated with increased risk for current wheezing (odds ratio, 2.36; 95% CI, 1.25-4.47 adjusted for asthma and current smoker) and this risk was related with the usage during the past year.

CONCLUSION

Young women taking oral contraceptives had a higher rate of current wheezing, suggesting that sex steroids may be of importance for respiratory health.

Gender, airborne chemical monitoring, and physical work environment are related to indoor air symptoms among nonindustrial workers in the Klang Valley, Malaysia

Objectives:

The purpose of this study was to analyze the relationship of airborne chemicals and the physical work environment risk element on the indoor air symptoms of nonindustrial workers.

Design:

A cross-sectional study consisting of 200 office workers. A random selection of 200 buildings was analyzed for exposure and indoor air symptoms based on a pilot study in the Klang Valley, Malaysia.

Methods:

A set of modified published questionnaires by the Department of Occupational Safety and Health (DOSH), Malaysia and a previous study (MM040NA questionnaire) pertaining to indoor air symptoms was used in the evaluation process of the indoor air symptoms. Statistical analyses involving logistic regression and linear regression were used to determine the relationship between exposure and indoor air symptoms for use in the development of an indoor risk matrix.

Results:

The results indicate that some indoor air pollutants (carbon monoxide, formaldehyde, total volatile organic compound, and dust) are related to indoor air symptoms of men and women. Temperature and relative humidity showed a positive association with complaints related to the perceived indoor environmental condition (drafts and inconsistency of temperature). Men predominantly reported general symptoms when stratification of gender involved exposure to formaldehyde. Women reported high levels of complaints related to mucosal and general symptoms from exposure to the dust level indoors.

Conclusion:

Exposure to pollutants (total volatile organic compounds, carbon monoxide, and formaldehyde) and physical stressors (air temperature and relative humidity) influence reported symptoms of office workers. These parameters should be focused upon and graded as one of the important elements in the grading procedure when qualitatively evaluating the indoor environment.

Gender difference of childhood overweight and obesity in predicting the risk of incident asthma: a systematic review and meta-analysis

The aims of our meta-analysis were (i) to quantify the predictability of childhood overweight and obesity on the risk of incident asthma; and (ii) to evaluate the gender difference on this relationship. The selection criteria included prospective cohort paediatric studies which use age- and sex-specific body mass index (BMI) as a measure of childhood overweight and the primary outcome of incident asthma. A total of 1,027 studies were initially identified through online database searches, and finally 6 studies met the inclusion criteria. The combined result of reported relative risk from the 6 included studies revealed that overweight children conferred increased risks of incident asthma as compared with non-overweight children (relative risk, 1.19; 95% confidence interval [CI], 1.03-1.37). The relationship was further elevated for obesity vs. non-obesity (relative risk, 2.02; 95% CI, 1.16-3.50). A dose-responsiveness of elevated BMI on asthma incidence was observed (P for trend, 0.004). Obese boys had a significantly larger effect than obese girls (relative risk, boys: 2.47; 95% CI, 1.57-3.87; girls: 1.25; 95% CI, 0.51-3.03), with significant dose-dependent effect. Proposed mechanisms of gender difference could be through pulmonary mechanics, sleep disordered breathing and leptin. Further research might be needed to better understand the exact mechanism of gender difference on the obesity-asthma relationship.

Obesity and the occurrence of bronchitis in adolescents

OBJECTIVE

Previous studies have shown that an elevated BMI was associated with higher risks of bronchitis among children. The magnitude of how increase in BMI influencing the risk of incident bronchitis remained unexplored. The objective of this study is to assess the association between BMI and the incidence of bronchitis in the Taiwan Children Health Study.

DESIGN

A school-based prospective cohort study.

METHODS

We conducted a population-based prospective cohort study among seventh-grade school children in 14 Taiwanese communities. A total of 3,634 adolescents completed follow-up questionnaire in 2009. Associations between BMI and incident bronchitis were analyzed by multiple Poisson regression models, taking overdispersion into account.

RESULTS

Among eligible cohort participants without bronchitis at study entry, the proportion of overweight and obesity were 32.1% and 17.9%. Overweight was 40.7% and obesity was 27.7% among those with incident bronchitis. The BMI percentile categories showed significant increasing trends for bronchitis in total eligible children and in girls (P for trend <0.001). Overweight and obesity were both associated with increased risks of incident bronchitis. This association was significant in girls only while stratified by gender.

CONCLUSIONS

Our data showed that the BMI percentile and weight status were associated with higher risks of incident bronchitis in adolescents, especially in girls.

Genetic ancestry and its association with asthma exacerbations among African American subjects with asthma

BACKGROUND

There are large and persisting disparities in severe asthma exacerbations by race-ethnicity, and African American subjects are among those at greatest risk. It is unclear whether this increased risk solely represents differences in environmental exposures and health care or whether there is a predisposing genetic component.

OBJECTIVE

We sought to assess the relationship between genetic ancestry and severe exacerbations among African American subjects with asthma.

METHODS

Participants were part of the Study of Asthma Phenotypes and Pharmacogenomic Interactions by Race-ethnicity (SAPPHIRE). These subjects were 12 to 56 years of age, received care from a single large health system, and had a physician's diagnosis of asthma. Genetic ancestry was estimated by using a set of validated ancestry informative markers. Severe exacerbations (ie, asthma-related emergency department visits, hospitalizations, and burst oral steroid use) were prospectively identified from health care claims.

RESULTS

We assessed genetic ancestry in 392 African American subjects with asthma. The average proportion of African ancestry was 76.1%. A significant interaction was identified between ancestry and sex on severe exacerbations, such that the risk was significantly higher with increasing African ancestry among male but not female subjects. The association among male subjects persisted after adjusting for potential confounders (relative rate, 4.30 for every 20% increase in African ancestry; P = .029).

CONCLUSIONS

African ancestry was significantly and positively associated with severe exacerbations among male African American subjects. These findings suggest that a portion of the risk of asthma exacerbations in this high-risk group is attributable to a genetic risk factor that partitions with ancestry.

T1 and T2 ADAM33 single nucleotide polymorphisms and the risk of childhood asthma in a Saudi Arabian population: a pilot study

BACKGROUND AND OBJECTIVES

Genetic association studies have demonstrated that over 100 variants in target genes (including ADAM33) are associated with airway remodeling and hyper-responsiveness in different ethnic groups; however, this has never been evaluated in Arabic populations. The objective of this study was to determine whether ADAM33 polymorphisms that are associated with asthma in a population of asthmatic children from Saudi Arabia.

DESIGN AND SETTING

A cross-sectional pilot study comparing the polymorphisms of normal subjects and asthmatic patients from Saudi Arabia over a period of 1 year.

PATIENTS AND METHODS

One hundred and seven Saudi asthmatic children and 87 healthy Saudi children of 3-12 years old were assessed for allelic association of ADAM33 T1 (rs2280091), T2 (rs2280090), ST+4 (rs44707) and S1 (rs3918396) SNPs to asthma. Genotyping was done by real-time PCR, multiplex ARMS and PCR-RFLP.

RESULTS

T1 and T2 SNP genotype frequencies in asthmatic children were significantly different compared to controls (P < .05), indicating allelic association with asthma. The T1 A/G and G/G and the T2 A/G and A/A genotypes (P=.0013 and P=.008, respectively) but not S1 and ST+4, increased the risk of asthma when using the best fit dominant model. Strong linkage disequilibrium between T1 (rs2280091) and T2 (rs2280090) was observed (r2=0.83; D'=0.95; P < .001). The haplotype G-A-A-C was significantly more frequent in asthmatics, thus supporting the association of T1 G-allele and T2 A-allele with increased predisposition to asthma (P=.007).

CONCLUSIONS

T1 A/G and T2 G/A ADAM33 polymorphisms, but not S1 or ST+4, were significantly associated with asthma development in Saudi children, like those reported for white and Hispanic populations in the United States.

Non-atopic males with adult onset asthma are at risk of persistent airflow limitation

BACKGROUND

Patients with asthma have on average a more rapid decline in FEV (1) as compared with the general population. Recent cluster analysis has revealed different asthma phenotypes that can be distinguished by age of onset and reversibility of airflow limitation.

OBJECTIVE

This study aimed at detecting risk factors associated with persistent airflow limitation in patients with the adult onset asthma phenotype.

METHODS

We recruited 88 patients with adult onset (≥ 18 years) asthma from an academic pulmonary outpatient clinic in the Netherlands. The associations of age, age of asthma onset, asthma duration, gender, race, atopy, smoking pack-years, BMI, use of oral corticosteroids with post-bronchodilator FEV (1) /FVC were investigated.

RESULTS

Multiple linear regression analysis showed an association of absence of atopy (r = -0.27, B = -0.26, P = 0.01) and male gender (r = 0.31, B = 0.30, P = 0.004) with post-bronchodilator FEV (1) /FVC. Multiple logistic regression analysis showed that male patients were 10.8 (CI: 2.6-45.2) times the odds than women to have an FEV (1) /FVC < 0.7, and non-atopic patients were 5.2 (CI: 1.3-20.3) times the odds to have an FEV (1) /FVC < 0.7 than atopic patients.

CONCLUSIONS AND CLINICAL RELEVANCE

We conclude that in patients with adult onset asthma, male gender and absence of atopy are associated with persistent airflow limitation. This might suggest that amongst patients with adult onset asthma, non-atopic male patients are at increased risk of accelerated decline in lung function.

Sex differences and sex steroids in lung health and disease

Sex differences in the biology of different organ systems and the influence of sex hormones in modulating health and disease are increasingly relevant in clinical and research areas. Although work has focused on sex differences and sex hormones in cardiovascular, musculoskeletal, and neuronal systems, there is now increasing clinical evidence for sex differences in incidence, morbidity, and mortality of lung diseases including allergic diseases (such as asthma), chronic obstructive pulmonary disease, pulmonary fibrosis, lung cancer, as well as pulmonary hypertension. Whether such differences are inherent and/or whether sex steroids play a role in modulating these differences is currently under investigation. The purpose of this review is to define sex differences in lung structure/function under normal and specific disease states, with exploration of whether and how sex hormone signaling mechanisms may explain these clinical observations. Focusing on adult age groups, the review addresses the following: 1) inherent sex differences in lung anatomy and physiology; 2) the importance of certain time points in life such as puberty, pregnancy, menopause, and aging; 3) expression and signaling of sex steroid receptors under normal vs. disease states; 4) potential interplay between different sex steroids; 5) the question of whether sex steroids are beneficial or detrimental to the lung; and 6) the potential use of sex steroid signaling as biomarkers and therapeutic avenues in lung diseases. The importance of focusing on sex differences and sex steroids in the lung lies in the increasing incidence of lung diseases in women and the need to address lung diseases across the life span.

Conventional epidemiology underestimates the incidence of asthma and wheeze-a longitudinal population-based study among teenagers

Background

Because of shifts in the gender ratio and incidence and remission rates of asthma during the teen ages, the methodology of incidence studies among teenagers is important, i.e. if the time intervals between surveys are too long, the incident cases might not be properly identified. The aim was to study the impact of study design on the incidence rates of asthma and wheeze during the teen ages.

Methods

In a study about asthma and allergic diseases within the OLIN studies (Obstructive Lung Disease in northern Sweden), a cohort of school children (n = 3,430) was followed annually by questionnaire from age 8 yrs. In the endpoint survey (age 18 yrs) 2,582 (75% of original responders) participated. Incident cases from age 12-18 yrs were identified by two methods: annual questionnaire reports (AR) and baseline-endpoint surveys only (BE).

Results

The cumulative incidence of asthma and wheeze was significantly higher based on AR compared to BE. Compared to the incidence rates based on all the annual surveys, the calculated average annual rates based on BE were in general lower both among the boys and among the girls. There were no differences between boys and girls in incidence rates of asthma or wheeze during the early teen years. However, from the age of 15 years, the annual incidence rates were significantly or borderline significantly higher among girls than boys. At onset, the additional cases of current asthma identified by AR had significantly less severe asthma than those identified in BE (p < 0.02).

Conclusion

the size of the incidence of asthma and wheeze during the teen ages was influenced by study design. By using the conventional prospective study design with longer follow-up time, the incidence was underestimated.