Asthma Remission by Age at Diagnosis and Gender in a Population-Based Study

Characteristics of Adults With Severe Asthma in Childhood: A 60-Year Follow-up Study

BACKGROUND

Childhood asthma is a prevalent condition with potential impact on adult life.

RESEARCH QUESTION

In a 60-year follow-up study of adults with a history of severe childhood asthma, what are the potential differences in characteristics between individuals with persistent asthma and asthma remission in adulthood?

STUDY DESIGN AND METHODS

Danish adults with a history of childhood asthma and a 4-month stay in at an asthma care facility in Kongsberg, Norway (1950-1979) in childhood were included. Recruitment was carried out through social media and personal invitation letters. Participants completed questionnaires and underwent spirometry, bronchial provocation, and bronchodilator reversibility and blood tests. Asthma remission was defined as no use of asthma medication and no asthma symptoms within the past 12 months, with the remaining participants being classified as having current asthma.

RESULTS

Among 1,394 eligible participants, 232 participants completed the follow-up. Ninety percent had current asthma, of whom 26% reported exacerbations in the past year. Only 16% of all the participants were managed in secondary care. Common comorbidities were allergic rhinitis (60%), hypertension (21%), eczema (16%), and cataract (8%). Compared with participants in remission, participants with persistent asthma showed higher total IgE (P = .03) and both lower FEV1 % predicted (P = .03) and FEV1 to FVC ratio (P < .001), as well as numerically higher fractional exhaled nitric oxide and blood eosinophil count.

INTERPRETATION

Our 60-year follow-up study of adults with a history of severe childhood asthma revealed that nine of 10 participants still had current asthma. Persistent asthma was associated with lower lung function and higher levels of type 2 inflammatory biomarkers compared with asthma remission.

Documentation of comorbidities, lifestyle factors, and asthma management during primary care scheduled asthma contacts

Systematically assessing asthma during follow-up contacts is important to accomplish comprehensive treatment. No previous long-term studies exist on how comorbidities, lifestyle factors, and asthma management details are documented in scheduled asthma contacts in primary health care (PHC). We showed comorbidities and lifestyle factors were poorly documented in PHC in this real-life, 12-year, follow-up study. Documented information on rhinitis was found in 8.9% and BMI, overweight, or obesity in ≤1.5% of the 542 scheduled asthma contacts. Of the 145 patients with scheduled asthma contacts, 6.9% had undergone revision of their inhalation technique; 16.6% had documentation of their asthma action plan. Screening of respiratory symptoms was recorded in 79% but nasal symptoms in only 15.5% of contacts. Lifestyle guidance interventions were found in <1% of contacts. These results, based on documented patient data, indicate a need exists to further improve the assessment and guidance of asthma patients in PHC.

Cluster Analysis of Finnish Population-Based Adult-Onset Asthma Patients

BACKGROUND

Phenotypes of adult asthma have been identified in previous studies but rarely in population-based settings.

OBJECTIVE

To identify clusters of adult-onset asthma in a Finnish population-based study on subjects born before 1967.

METHODS

We used population-based data from 1350 asthmatics with adult-onset asthma (Adult Asthma in Finland) from Finnish national registers. Twenty-eight covariates were selected based on literature. The number of covariates was reduced by using factor analysis before cluster analysis.

RESULTS

Five clusters (CLU1-CLU5) were identified, 3 clusters with late-onset adult asthma (onset ≥40 years) and 2 clusters with onset at earlier adulthood (<40 years). Subjects in CLU1 (n = 666) had late-onset asthma and were nonobese, symptomatic, and predominantly female with few respiratory infections during childhood. CLU2 (n = 36) consisted of subjects who had earlier-onset asthma, were predominantly female, obese with allergic asthma, and had recurrent respiratory infections. Subjects in CLU3 (n = 75) were nonobese, older, and predominantly men with late-onset asthma, smoking history, comorbidities, severe asthma, least allergic diseases, low education, many siblings, and childhood in rural areas. CLU4 (n = 218) was a late-onset cluster consisting of obese females with comorbidities, asthma symptoms, and low education level. Subjects in CLU5 (n = 260) had earlier onset asthma, were nonobese, and predominantly allergic females.

CONCLUSIONS

Our population-based adult-onset asthma clusters take into account several critical factors such as obesity and smoking, and identified clusters that partially overlap with clusters identified in clinical settings. Results give us a more profound understanding of adult-onset asthma phenotypes and support personalized management.

Relationship between early life asthma and chronic airway disease in adult life - in search for disease trajectories over the life span- the RELATE study based on the Kongsberg cohort

BACKGROUND

Chronic airway disease in adults may have its origin in early life. The purpose of this study is to investigate the long-term prognosis of severe childhood asthma in search for an association between asthma in early life and obstructive lung disease in adulthood.

METHODS

This study is based on the Kongsberg cohort, which includes approximately 5000 children with severe asthma with a 4-month stay at the asthma care facility in Kongsberg, Norway during the years 1950 to 1979. An on average 60-year observational study based on a follow-up examination will be performed including questionnaires, blood samples, and tests of lung function and bronchial responsiveness. Blood samples will be stored in a biobank. In addition, we will conduct further analyses of the cohort based on nationwide register data, including socio-economic parameters and mortality.

DISCUSSION

Chronic airway disease is associated with substantial burden for both the individual patient and society. Our knowledge of early life origins of chronic airway disease later in life has been increasing in recent decades but is still limited. By exploring early life risk factors for chronic airway disease in adulthood, we may gain insights paving the way for future reduction in the burden of chronic airway diseases.

Exogenous female sex steroid hormones and new-onset asthma in women: a matched case-control study

BACKGROUND

Evidence on the role of exogenous female sex steroid hormones in asthma development in women remains conflicting. We sought to quantify the potential causal role of hormonal contraceptives and menopausal hormone therapy (MHT) in the development of asthma in women.

METHODS

We conducted a matched case-control study based on the West Sweden Asthma Study, nested in a representative cohort of 15,003 women aged 16-75 years, with 8-year follow-up (2008-2016). Data were analyzed using Frequentist and Bayesian conditional logistic regression models.

RESULTS

We included 114 cases and 717 controls. In Frequentist analysis, the odds ratio (OR) for new-onset asthma with ever use of hormonal contraceptives was 2.13 (95% confidence interval [CI] 1.03-4.38). Subgroup analyses showed that the OR increased consistently with older baseline age. The OR for new-onset asthma with ever MHT use among menopausal women was 1.17 (95% CI 0.49-2.82). In Bayesian analysis, the ORs for ever use of hormonal contraceptives and MHT were, respectively, 1.11 (95% posterior interval [PI] 0.79-1.55) and 1.18 (95% PI 0.92-1.52). The respective probability of each OR being larger than 1 was 72.3% and 90.6%.

CONCLUSIONS

Although use of hormonal contraceptives was associated with an increased risk of asthma, this may be explained by selection of women by baseline asthma status, given the upward trend in the effect estimate with older age. This indicates that use of hormonal contraceptives may in fact decrease asthma risk in women. Use of MHT may increase asthma risk in menopausal women.

Mild asthma: Lessons learned and remaining questions

Patients living with mild disease represent the largest proportion of asthma patients. There are significant challenges in proposing a definition that would best describe these patients, while also accurately identifying at-risk individuals. Current literature suggests considerable inflammatory and clinical heterogeneity within this group. Research has shown that these patients are at risk of poor control, exacerbations, lung function decline, and death. Despite conflicting data on its prevalence, eosinophilic inflammation appears to be a predictor of poorer outcomes in mild asthma. There is an immediate need to better understand phenotypic clusters in mild asthma. It is also important to understand factors that influence disease progression and remission, as it is evident that both vary in mild asthma. Guided by robust literature that supports inhaled corticosteroid-based strategies over short-acting beta-agonist (SABA) reliant regimens, the management of these patients has evolved considerably. Unfortunately, SABA use remains high in clinical practice despite strong advocacy from the Global Initiative for Asthma. Future mild asthma research should explore the role of biomarkers, develop prediction tools based on composite risk scores, and explore targeted therapies at least for at-risk individuals.

Allergic sensitisation and type-2 inflammation is associated with new-onset and persistent allergic disease

BACKGROUND

Allergic disease is common. The aim of this study was to look at the change in asthma and rhinitis over time and to characterise factors contributing to remission and persistence of disease.

METHODS

This cohort study included 255 individuals with or without asthma and or rhinitis that participated in a population survey and a follow-up 10 years later. The participants were tested for allergic sensitisation, total IgE, multiplex allergen component analysis and type-2 inflammatory markers: exhaled nitric oxide (F_E NO), eosinophil cationic protein (ECP) and eosinophil-derived neurotoxin (EDN).

RESULTS

Of the 132 healthy individuals, 112 remained healthy, 16 developed rhinitis, 4 asthma and rhinitis over the 10 years. Out of 82 subjects with rhinitis, 26 went into remission, 53 remained unchanged and 3 developed asthma in addition to rhinitis. None of the 41 participants with asthma and rhinitis went into remission. Subjects with persistent rhinitis and asthma had higher levels of total IgE (odds ratio [OR] 95% confidence interval [CI]: 6.16 [3.05-12.5]) at baseline and after 10 years, and F_E NO and ECP at baseline (OR per log unit increase, 95% CI 5.21 [1.20-22.7] and 6.32 [1.52-26.4], respectively), compared with those that remained healthy. Subjects with persistent rhinitis were more likely to be sensitised to grass pollen and had higher total IgE levels than those that went into remission. Individuals with persistent asthma were more likely to be sensitised to tree pollen and furry animals than those with only persistent rhinitis (OR 95% CI: 3.50 [1.29-9.49] and 6.73 [2.00-22.6], respectively).

CONCLUSION

IgE sensitisation and total IgE levels are associated with the persistence of rhinitis and asthma. Participants with persistent allergic disease had higher levels of allergen sensitisation and type 2 inflammation markers at baseline than those who remained healthy.

Validation of Diagnostic Coding for Asthma in an Electronic Health Record System in Hong Kong

Background

Electronic health record (EHR) databases can facilitate epidemiology research into various diseases including asthma. Given the diagnostic challenges of asthma, the validity of the coding in EHR requires clarification. We aimed to assess the validity of International Classification of Diseases, 9th Revision (ICD-9) code algorithms for identifying asthma in the territory-wide electronic medical health record system of the Clinical Data Analysis and Reporting System (CDARS) in Hong Kong.

Methods

Adult patients who had the diagnosis of asthma input from all public hospitals in Hong Kong and those from Queen Mary Hospital in 2011-2020 were identified using the ICD-9 code of 493 (493.0, 493.1, 493.2, and 493.9) by CDARS. Patients' clinical record and spirometry were reviewed by two respiratory specialists to confirm the presence of asthma in the randomly selected cases.

Results

There were 43,454 patients who had the diagnostic code of asthma among all public hospitals in Hong Kong and 1852 in Queen Mary Hospital in the same period. A total of 200 cases were randomly selected and validated using medical record and spirometry review by a respiratory specialist. The overall positive predictive value (PPV) was 85.0% (95% CI 80.1-89.9%).

Conclusion

This was the first ICD-9 code validation for CDARS (EHR) in Hong Kong on asthma. Our study demonstrated that using ICD-9 code (493.0, 493.1, 493.2 and 493.9) to identify asthma can result in a PPV that was reliable to support the utility of the CDARS database for further research on asthma among the Hong Kong population.

Nonrespiratory Diseases in Adults Without and With Asthma by Age at Asthma Diagnosis

BACKGROUND

Chronic nonrespiratory diseases are seemingly more prevalent in subjects with than without asthma, and asthma seems to differentiate by age of onset. However, studies with comparison of nonrespiratory diseases in subjects with and without asthma, considering asthma age of onset, are scarce.

OBJECTIVE

To compare the quantity and type of chronic nonrespiratory diseases in adults with and without asthma considering age at asthma diagnosis.

METHODS

In 2016, a FinEsS questionnaire was sent to 16,000 20- to 69-year-old adults randomly selected in Helsinki and Western Finland populations. Physician-diagnosed asthma was categorized to early (0-11), intermediate (12-39), and late-diagnosed (40-69 years).

RESULTS

A total of 8199 (51.5%) responded, and 842 (10.3%) reported asthma and age at diagnosis. In age and sex-adjusted binary logistic regression model, the most represented nonrespiratory disease was treated gastroesophageal reflux disease in early-diagnosed (odds ratio, 1.93; 95% CI, 1.17-3.19; P = .011) and osteoporosis in both intermediate-diagnosed (odds ratio, 3.45; 95% CI, 2.01-5.91; P < .001) and late-diagnosed asthma (odds ratio, 2.91; 95% CI, 1.77-4.79; P < .001), compared with subjects without asthma. In addition, gastroesophageal reflux disease, depression, sleep apnea, painful condition, and obesity were significantly more common in intermediate- and late-diagnosed asthma compared with without asthma, and similarly anxiety or panic disorder in intermediate-diagnosed and hypertension, severe cardiovascular disease, arrhythmia, and diabetes in late-diagnosed asthma. In age-adjusted analyses, having 3 or more nonrespiratory diseases was more common in intermediate (12.1%) and late-diagnosed asthma (36.2%) versus without asthma (10.4%) (both P < .001).

CONCLUSIONS

Nonrespiratory diseases were more common in adults with asthma than in adults without asthma. The type of nonrespiratory diseases differed, and their frequency increased by increasing age at asthma diagnosis.

Discontinuation and reduction of asthma medications after metabolic and bariatric surgery: A systematic review and meta-analysis

Obesity is a risk factor for asthma. Metabolic and bariatric surgery (MBS) is a safe and effective treatment option for obesity. Weight reduction via MBS, in turn, may improve asthma outcomes and decrease the need for asthma medications. The aim of the systematic review and meta-analysis is to explore the available evidence focused on the impact of MBS on the improvement of asthma outcomes via the discontinuation and reduction of asthma medications. After a comprehensive search in the PubMed, Embase, and Cochrane Central Register of Controlled Trials (CENTRAL) databases, 15 studies, including pre-post MBS data on asthma medication use among adults, were eligible for the systematic review. Thirteen studies reported the proportion of patient who discontinued asthma medication post-MBS and was meta-analyzed using random effects. Results showed 54% patients completely discontinued asthma medications (95% confidence interval 42%-67%, I²  = 86.2%, p < 0.001). The average number of asthma medications was also decreased by approximately 22%-46%. MBS provides strong therapeutic benefits for patients with asthma, as evidenced by the complete discontinuation of asthma medications in over 50% of MBS completers. The inference was limited by the small number, variations in follow-up time and rates, and heterogeneity of studies. Studies that include more ethnically diverse participant samples are needed to improve generalizability.

Identification of Asthma Phenotypes in the Spanish MEGA Cohort Study Using Cluster Analysis

INTRODUCTION

The definition of asthma phenotypes has not been fully established, neither there are cluster studies showing homogeneous results to solidly establish clear phenotypes. The purpose of this study was to develop a classification algorithm based on unsupervised cluster analysis, identifying clusters that represent clinically relevant asthma phenotypes that may share asthma-related outcomes.

METHODS

We performed a multicentre prospective cohort study, including adult patients with asthma (N=512) from the MEGA study (Mechanisms underlying the Genesis and evolution of Asthma). A standardised clinical history was completed for each patient. Cluster analysis was performed using the kernel k-groups algorithm.

RESULTS

Four clusters were identified. Cluster 1 (31.5% of subjects) includes adult-onset atopic patients with better lung function, lower BMI, good asthma control, low ICS dose, and few exacerbations. Cluster 2 (23.6%) is made of adolescent-onset atopic asthma patients with normal lung function, but low adherence to treatment (59% well-controlled) and smokers (48%). Cluster 3 (17.1%) includes adult-onset patients, mostly severe non-atopic, with overweight, the worse lung function and asthma control, and receiving combination of treatments. Cluster 4 (26.7%) consists of the elderly-onset patients, mostly female, atopic (64%), with high BMI and normal lung function, prevalence of smokers and comorbidities.

CONCLUSION

We defined four phenotypes of asthma using unsupervised cluster analysis. These clusters are clinically relevant and differ from each other as regards FEV1, age of onset, age, BMI, atopy, asthma severity, exacerbations, control, social class, smoking and nasal polyps.

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.

Clinical Remission of Asthma and Allergic Rhinitis - in a Longitudinal Population Study

BACKGROUND

Although asthma and allergic rhinitis are chronic diseases, some patients experience periods of remission. Information on prognostic factors associated with the remission of asthma and allergic rhinitis is valuable in resource prioritization. This study investigated factors associated with the clinical remission of asthma and allergic rhinitis.

METHODS

In the Respiratory Health In Northern Europe (RHINE) study, data was collected with questionnaires in stage one (RHINE I, 1989-1992) and two follow-ups (RHINE II, 1999-2001 and RHINE III, 2010-2012) from Sweden, Norway, Denmark, Iceland and Estonia. Clinical remission was defined as having reported asthma or allergic rhinitis in RHINE I or RHINE II but not in RHINE III.

RESULTS

Of 13,052 participants, 975 (7.5%) reported asthma in RHINE I or RHINE II, and 3379 (25.9%) allergic rhinitis. Clinical remission of asthma and allergic rhinitis was found in 46.4% and 31.8%, respectively. Living in Estonia (OR (95% CI) 2.44 (1.22-4.85)) and living in an apartment (1.45 (1.06-1.98)) were related to remission of asthma, while subjects reporting allergic rhinitis (0.68 (0.51-0.90)), asthma onset ≤ 12 years of age (0.49 (0.35-0.68)), receiving treatment with antibiotics for respiratory illness (0.64 (0.47-0.87)) were less likely to have asthma remission. Factors related to a higher likelihood of remission of allergic rhinitis were no asthma at baseline, age ≥ 58 years in RHINE III, allergic rhinitis onset after 12 years of age, living in rural areas as a child, having only a primary school education and not being pregnant.

CONCLUSION

Clinical remission was found in almost one-half of those with asthma and one-third of persons with allergic rhinitis. Coexisting allergic symptoms were associated with less clinical asthma remission. Age, asthma symptoms and environmental factors in childhood, such as living in a rural area, were found to influence the clinical remission of allergic rhinitis.

Impacts of COVID-19 Prevention and Control Measures on Asthma-Related Hospital and Outpatient Visits in Yichang, China

This article investigates the impact of COVID-19 lockdown and regular epidemic prevention and control after lifting lockdown on asthma-related hospital and outpatient visits in Yichang. Data on the general outpatient department (GOPD), emergency department (ED) and intensive care unit (ICU) visits for asthma from 15 November 2019 to 21 May 2020 and the corresponding from 2018 to 2019 were collected from eight tertiary hospitals in municipal districts. The controlled interrupted time series (CITS) analysis was used to investigate the level and long-term trend changes of weekly asthma visits during lockdown and regular epidemic prevention and control, and stratified by type of visits and age. A total of 9347 asthma-related hospital and outpatient visits were analyzed. The CITS showed that after the implementation of lockdown, the weekly visits of asthma patients immediately decreased by 127.32 (p = 0.002), and the level of GOPD and ED/ICU visits immediately decreased significantly. After implementation of regular prevention, the level and trend of overall weekly visits changed insignificantly compared with the lockdown period. The weekly visits of GOPD adults immediately increased by 51.46 (p < 0.001), and the trend of ED/ICU adults decreased by 5.06 (p = 0.003) visits per week compared with lockdown period. The COVID-19 lockdown in Yichang was related to the decrease in hospital and outpatient visits for asthma. After the implementation of subsequent regular prevention and control measure, only the GOPD visits of adults increased compared with lockdown period.

Age at asthma diagnosis is related to prevalence and characteristics of asthma symptoms

Background

Although asthma may begin at any age, knowledge about relationship between asthma age of onset and the prevalence and character of different symptoms is scarce.

Objectives

The aim of this study was to investigate if adult-diagnosed asthma is associated with more symptoms and different symptom profiles than child-diagnosed asthma.

Methods

A FinEsS postal survey was conducted in a random sample of 16 000 20-69-year-old Finnish adults in 2016. Those reporting physician-diagnosed asthma and age at asthma diagnosis were included. Age 18 years was chosen to delineate child- and adult-diagnosed asthma.

Results

Of responders (N = 8199, 51.5%), 842 (10.3%) reported asthma diagnosis. Adult-diagnosed asthma was reported by 499 (59.3%) and child-diagnosed by 343 (40.7%). Of responders with adult-diagnosed and child-diagnosed asthma, 81.8% versus 60.6% used asthma medication (p < 0.001), respectively. Current asthma was also more prevalent in adult-diagnosed asthma (89.2% versus 72.0%, p < 0.001). Risk factors of attacks of breathlessness during the last 12 months were adult-diagnosis (OR = 2.41, 95% CI 1.64–3.54, p < 0.001), female gender (OR = 1.49, 1.07–2.08, p = 0.018), family history of asthma (OR = 1.48, 1.07–2.04, p = 0.018) and allergic rhinitis (OR = 1.49, 1.07–2.09, p = 0.019). All the analysed asthma symptoms, except dyspnea in exercise, were more prevalent in adult-diagnosed asthma in age- and gender-adjusted analyses (p = 0.032-<0.001) which was also more often associated with 5 or more asthma symptoms (p < 0.001) and less often with non-symptomatic appearance (p < 0.001) than child-diagnosed asthma.

Conclusion

Responders with adult-diagnosed asthma had more often current asthma and a higher and multiform asthma symptom burden, although they used asthma medication more often compared to responders with child-diagnosed asthma.

Correlation of Activation Site and Number with the Clinical Response to Bronchial Thermoplasty

Objective

Methods

Results

Conclusion

Participation in scheduled asthma follow-up contacts and adherence to treatment during 12-year follow-up in patients with adult-onset asthma

Background

Poor treatment compliance is a common problem in the treatment of asthma. To our knowledge, no previous long-term follow-up studies exist on how scheduled asthma follow-up contacts occur in primary health care (PHC) versus secondary care and how these contacts relate to adherence to medication and in participation to further scheduled asthma contacts. The aim of this study was to evaluate occurrence of scheduled asthma contacts and treatment compliance in PHC versus secondary care, and to identify the factors associated with non-participation to scheduled contacts.

Methods

Patients with new adult-onset asthma (n = 203) were followed for 12 years in a real-life asthma cohort of the Seinäjoki Adult Asthma Study (SAAS). The first contacts were mainly carried out in secondary care and therefore the actual follow-up time including PHC visits was 10 years.

Results

A majority (71%) of the patients had ≥ 2 scheduled asthma contacts during 10-year follow-up and most of them (79%) mainly in PHC. Patients with follow-up contacts mainly in PHC had better adherence to inhaled corticosteroid (ICS) medication during the whole 12-year period compared to patients in secondary care. In the study population, 29% of the patients had only 0–1 scheduled asthma contacts during the follow-up. Heavy alcohol consumption predicted poor participation in scheduled contacts.

Conclusions

Patients with mainly PHC scheduled asthma contacts were more adherent to ICS medication than patients in the secondary care. Based on our results it is necessary to pay more attention to actualization of asthma follow-up visits and systematic assessment of asthma patients including evaluation of alcohol consumption.

Trial registration Seinäjoki Adult Asthma Study is retrospectively registered at www.ClinicalTrials.gov with identifier number NCT02733016. Registered 11 April 2016.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12890-022-01850-1.

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.

Natural history and associated early life factors of childhood asthma: a population registry-based cohort study in Denmark

OBJECTIVE

Asthma is a common chronic disease that imposes a substantial burden on individuals and society. However, the natural history of childhood asthma in a large population remained to be studied. This study aimed to describe the natural course of childhood asthma and examine the association between early life factors and childhood asthma.

DESIGN

A population-based cohort study.

SETTING

This study was based on the national registry data in Denmark.

PARTICIPANTS

All liveborn singletons in Denmark during 1995-1997 were identified and followed them till the end of 2009. Finally, 193 673 children were eligible for our study.

EXPOSURES

The following characteristics were examined as potential early life factors associated with childhood asthma, including parity, maternal asthma history, maternal smoking during pregnancy, maternal social status, delivery method and gender.

MAIN OUTCOMES AND MEASURES

Asthma cases were identified on the basis of hospitalisation for asthma and prescriptions for antiasthmatic medications. Asthma remission was defined as no hospitalisation or prescription recorded for 2 years. Cox proportional hazards' regression and logistic regression were used to evaluate the association between early life factors and the occurrence and remission of childhood asthma.

RESULTS

The cumulative occurrence rate of asthma in children aged 3-14 years was 13.3% and the remission rate was 44.1%. The occurrence rate decreased with age. Being female had a lower risk of asthma (HR: 0.72, 95% CI 0.70 to 0.74) and higher remission rate of asthma (HR: 1.18, 1.13 to 1.22), while maternal asthma was associated with a higher risk of asthma (HR: 2.15, 2.04 to 2.26) and decreased remission rate of asthma (HR: 0.79, 0.73 to 0.85). These patterns remained the same for early onset asthma.

CONCLUSIONS

Female gender had a lower risk of asthma and a better chance of remission, while maternal asthma history had an opposite effect. The early life factors may influence the natural course of childhood asthma.

Influence of Childhood Exposure to a Farming Environment on Age at Asthma Diagnosis in a Population-Based Study

Purpose

Asthma is a heterogeneous disease, and factors associated with different asthma phenotypes are poorly understood. Given the higher prevalence of farming exposure and late diagnosis of asthma in more rural Western Finland as compared with the capital of Helsinki, we investigated the relationship between childhood farming environment and age at asthma diagnosis.

Methods

A cross-sectional population-based study was carried out with subjects aged 20–69 years in Western Finland. The response rate was 52.5%. We included 3864 participants, 416 of whom had physician-diagnosed asthma at a known age and with data on the childhood environment. The main finding was confirmed in a similar sample from Helsinki. Participants were classified as follows with respect to asthma diagnosis: early diagnosis (0–11 years), intermediate diagnosis (12–39 years), and late diagnosis (40–69 years).

Results

The prevalence of asthma was similar both without and with childhood exposure to a farming environment (11.7% vs 11.3%). Allergic rhinitis, family history of asthma, ex-smoker, occupational exposure, and BMI ≥ 30 kg/m² were associated with a higher likelihood of asthma. Childhood exposure to a farming environment did not increase the odds of having asthma (aOR, 1.10; 95% CI, 0.87–1.40). It did increase the odds of late diagnosis (aOR, 2.30; 95% CI, 1.12–4.69), but the odds were lower for early (aOR, 0.49; 95% CI, 0.30–0.80) and intermediate diagnosis of asthma (aOR, 0.75; 95% CI, 0.47–1.18).

Conclusion

Odds were lower for early diagnosis of asthma and higher for late diagnosis of asthma in a childhood farming environment. This suggests a new hypothesis concerning the etiology of asthma when it is diagnosed late.

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