Sex-Based Differences in Asthma among Preschool and School-Aged Children in Korea

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

Bidirectional association between asthma and otitis media in children

BACKGROUND

This study explored the reciprocal association between otitis media and asthma in children.

METHODS

The 2002-2013 Korean Health Insurance Review and Assessment Service-National Sample Cohort participants < 15 years old were used. In study I, 14,665 asthma patients from 2002 through 2005 were selected. The asthma patients were matched 1:1 with the control I group, and the occurrence of otitis media was followed until 2013. In study II, 27,043 otitis media patients from 2002 through 2005 were selected. The otitis media patients were matched 1:1 with the control II group, and the occurrence of asthma was followed until 2013. Stratified Cox proportional hazard models were used to analyze the hazard ratio (HRs) of asthma for otitis media (study I) and otitis media for asthma (study II).

RESULTS

The HR for otitis media was 1.46 in asthma patients (95% confidence interval [CI] = 1.40-1.52, P < 0.001). The HR for asthma was 1.43 in otitis media patients (95% confidence interval [CI] = 1.36-1.50, P < 0.001).

CONCLUSION

Asthma and otitis media have a bidirectional association in children.

Personal and early life factors associated with new-onset asthma, remission, and persistence of asthma in a 2-year follow-up of schoolchildren

OBJECTIVE

The natural course of childhood asthma, after its onset, is characterized by periods of persistence, relapse and remission. To investigate personal and early life factors associated with new-onset asthma, persistence and remission among children.

METHODS

The study was conducted in the province of Saskatchewan, Canada. Children in grades Kindergarten to Grade 8 (ages 5-14 years) participated in a cross-sectional study in 2013. In 2015, we approached those who gave consent in 2013 to be re-contacted, creating a prospective cohort. Data were collected using questionnaires in both years. Participants in 2013 who also had data in 2015 (25%: n = 324/1,348) had their asthma status reclassified and longitudinal descriptors were applied: "no asthma", "new-onset asthma", "persistent" or "remission". Personal and early life factors associations with asthma outcomes in 2015 were evaluated.

RESULTS

Among those without asthma in 2013 (n = 245), the incidence of new-onset asthma in 2015 was 7.2%. Among those with asthma in 2013 (n = 79), 47.1% had remission and 52.9% had persistent asthma in 2015. Parental history of asthma (adjusted odds ratio (aOR): 4.99; 95% confidence interval (CI): 1.88-28.27), early life respiratory infection (aOR: 1.92; 95%CI: 1.47-7.88), early life allergy [aOR: 6.39; 95%CI: 1.34-30.58) and early life infection (aOR: 4.99; 95%CI: 1.19-20.93) were associated with new onset asthma. Similarly, while parental history of asthma (aOR: 1.13; 95%CI: 0.29-4.34), early life respiratory infection (aOR: 2.71; 95%CI: 0.70-10.45), and early life ear infection (aOR: 1.34; 95%CI: 0.36-5.05) were also positively association with persistent asthma, the associations were not statistically significant.

CONCLUSION

Parental history of asthma, early life respiratory infection and allergy might not only influence the onset of childhood asthma but also be associated with asthma persistence.

Increased risk of psoriasis in children and elderly patients with asthma: a longitudinal follow-up study using a national sample cohort

BACKGROUND

Several previous studies reported the elevated risk of asthma in children with psoriasis. This study aimed to extend previous research regarding the risk of psoriasis in children with asthma to an entire population subdivided by age.

METHODS

The 2002-2013 Korean Health Insurance Review and Assessment Service-National Sample Cohort (HIRA-NSC) was used. The 167,693 participants with asthma were matched with 167,693 control participants for age, sex, income, region of residence, hypertension history, diabetes history, and dyslipidemia history. In both the asthma and control groups, the occurrences of asthma were investigated. The crude and adjusted hazard ratios (HRs) and 95% confidence intervals (CIs) for psoriasis with respect to asthma status were determined using stratified Cox proportional hazards models. Subgroup analyses were conducted according to age and sex.

RESULTS

The prevalence of psoriasis was 0.5% (95% CI, 0.4% to 0.5%; n = 771/167,693) in the asthma group and 0.4% (95% CI, 0.3% to 0.4%; n = 589/167,693) in the control group (p < 0.001). The asthma group (adjusted HR = 1.19; 95% CI, 1.07 to 1.33; p = 0.002) demonstrated higher HRs for psoriasis than did the control group. This result was consistent in the <15 years old, ≥60 years old, and women subgroups.

CONCLUSION

Asthma was associated with the elevated risk of psoriasis. The possible risk of psoriasis needs to be considered when managing asthma patients. Future study is warranted for the risk of psoriasis according to the endotypes of asthma.

Prescription Patterns and Burden of Pediatric Asthma in Korea

Purpose

This study aimed to estimate the prevalence, prescription pattern and burden of pediatric asthma in Korea by analyzing the National Health Insurance (NHI) claims data.

Methods

We retrospectively analyzed the insurance claim records from the Korean NHI claims database from January 2010 to December 2014. Asthmatic patients were defined as children younger than 18 years, with appropriate 10th Revision of the International Classification of Diseases codes (J45 or J46) and a prescription for 1 or more asthma maintenance medications at the same date. Hospitalization and emergency department visits for asthma were defined as use of short-acting beta₂-agonists during hospital visits among asthmatic patients.

Results

There were 1,172,807 asthmatic children in 2010, which increased steadily to 1,590,228 in 2014 in Korea. The prevalence showed an increasing trend annually for all ages. The mean prevalence by age in those older than 2 years decreased during the study period (from 39.4% in the 2–3 year age group to 2.6% in the 15–18 year age group). In an outpatient prescription, leukotriene receptor antagonists were the most commonly prescribed medication for all ages. Patients older than 6 years for whom inhaled corticosteroids were prescribed comprised less than 15% of asthmatic patients. The total direct medical cost for asthma between 2010 and 2014 ranged from $376 to $483 million. Asthma-related medical cost per person reached its peak in $366 in 2011 and decreased to $275 in 2014.

Conclusions

The prevalence of pediatric asthma increased annually and decreased with age. Individual cost of asthma showed a decreasing trend in Korean children.

Gender disparity in pediatrics: a review of the current literature

BACKGROUND

Gender-based medicine is an innovative branch of biomedical research and represents a new perspective for the future of health research. Many studies have been published on gender medicine in adults but very few data regarding children are available.

LITERATURE SEARCH AND RESULTS

A literature search covering articles published between 1stJuly, 2006 and 1st February, 2017 and concerning children only was conducted using multiple keywords and standardized terminology in Pubmed database. The search was limited to English-language publications. All relevant articles on endocrines, neurological, psychiatric, gastrointestinal, immunological, oncological, rheumatic, pneumological disorders, infectious diseases and analgesia were evaluated and pertinent articles were included in this review. Most of the available studies on gender disparity in childhood are about endocrine and neuro-psychiatric disorders, while there are few data in other areas of medicine.

CONCLUSIONS

Even if several studies on pediatric gender differences can be found on literature, few of them move forwards to analyze the reasons of the observed diversity. No data on pharmacokinetic and pharmacodynamic differences between boys and girls can be found. Hence, more efforts should be directed to investigate these topics in childhood.

Estrogen Signaling Contributes to Sex Differences in Macrophage Polarization during Asthma

Allergic asthma is a chronic Th2 inflammation in the lungs that constricts the airways and presents as coughing and wheezing. Asthma mostly affects boys in childhood and women in adulthood, suggesting that shifts in sex hormones alter the course of the disease. Alveolar macrophages have emerged as major mediators of allergic lung inflammation in animal models as well as humans. Whether sex differences exist in macrophage polarization and the molecular mechanism(s) that drive differential responses are not well understood. We found that IL-4-stimulated bone marrow-derived and alveolar macrophages from female mice exhibited greater expression of M2 genes in vitro and after allergen challenge in vivo. Alveolar macrophages from female mice exhibited greater expression of the IL-4Rα and estrogen receptor (ER) α compared with macrophages from male mice following allergen challenge. An ERα-specific agonist enhanced IL-4-induced M2 gene expression in macrophages from both sexes, but more so in macrophages from female mice. Furthermore, IL-4-stimulated macrophages from female mice exhibited more transcriptionally active histone modifications at M2 gene promoters than did macrophages from male mice. We found that supplementation of estrogen into ovariectomized female mice enhanced M2 polarization in vivo upon challenge with allergen and that macrophage-specific deletion of ERα impaired this M2 polarization. The effects of estrogen are long-lasting; bone marrow-derived macrophages from ovariectomized mice implanted with estrogen exhibited enhanced IL-4-induced M2 gene expression compared with macrophages from placebo-implanted littermates. Taken together, our findings suggest that estrogen enhances IL-4-induced M2 gene expression and thereby contributes to sex differences observed in asthma.

Childhood asthma in Batumi, Georgia: Prevalence and environmental correlates

OBJECTIVE

A relative lack of data for Eastern Europe and unknown epidemiology of childhood asthma in Batumi (Georgia) justified a study aimed at determining the prevalence of physician-diagnosed asthma and related respiratory conditions, a comparison of the prevalence of these conditions between urban and rural children, and identification of their environmental correlates.

METHODS

Subjects of the cross-sectional population-based study were 3238 urban and 2081 rural children aged 5-17 years whose respiratory status was assessed using the ISAAC questionnaire.

RESULTS

The overall prevalence of asthma was larger in rural children than in urban children (2.8% vs. 1.8%, respectively; p = 0.01). Spastic bronchitis occurred with similar frequency in urban (7.8%) and rural children (6.5%). Compared with urban children, rural subjects had dry cough at night (13.1 vs 8.2%, p < 0.001) and attacks of dyspnea (4.7 vs 2.4%, p < 0.001) more often. The prevalence of other symptoms did not differ significantly between urban and rural subjects. Results of multivariate analyses showed that both asthma and spastic bronchitis were associated (p < 0.05) with parental history of asthma, dampness in the house, and poor financial standing of the family. In addition, asthma was related to coal/wood-based heating whereas spastic bronchitis was associated with passive smoking and lower parental education.

CONCLUSIONS

The findings show a low prevalence of ever-diagnosed asthma in the examined population. Nosological tradition and similar correlates of asthma and spastic bronchitis suggest that some cases of asthma might be included in the diagnostic category of spastic bronchitis.