Asthma and allergic diseases in preschool children in Korea: findings from the pilot study of the Korean Surveillance System for Childhood Asthma

Association of exposure to indoor molds and dampness with allergic diseases at water-damaged dwellings in Korea

This study aims to characterize levels of molds, bacteria, and environmental pollutants, identify the associations between indoor mold and dampness exposures and childhood allergic diseases, including asthma, allergic rhinitis, atopic dermatitis, using three different exposure assessment tools. A total of 50 children with their parents who registered in Seoul and Gyeonggi-do in Korea participated in this study. We collated the information on demographic and housing characteristics, environmental conditions, and lifestyle factors using the Korean version of the International Study of Asthma and Allergies in Childhood questionnaire. We also collected environmental monitoring samples of airborne molds and bacteria, total volatile organic compounds, formaldehyde, and particulate matter less than 10 µm. We evaluated and determined water damage, hidden dampness, and mold growth in dwellings using an infrared (IR) thermal camera and field inspection. Univariate and multivariate regression analyses were performed to evaluate the associations between prevalent allergic diseases and exposure to indoor mold and dampness. Indoor mold and bacterial levels were related to the presence of water damage in dwellings, and the mean levels of indoor molds (93.4 ± 73.5 CFU/m3) and bacteria (221.5 ± 124.2 CFU/m3) in water-damaged homes were significantly higher than those for molds (82.0 ± 58.7 CFU/m3) and for bacteria (152.7 ± 82.1 CFU/m3) in non-damaged dwellings (p < 0.05). The crude odds ratios (ORs) of atopic dermatitis were associated with < 6th floor (OR = 3.80), and higher indoor mold (OR = 6.42) and bacterial levels (OR = 6.00). The crude ORs of allergic diseases, defined as a group of cases who ever suffered from two out of three allergic diseases, e.g., asthma and allergic rhinitis, and allergic rhinitis were also increased by 3.8 and 9.3 times as large, respectively, with water damage (+) determined by IR camera (p < 0.05). The adjusted OR of allergic rhinitis was significantly elevated by 10.4 times in the water-damaged dwellings after adjusting age, sex, and secondhand smoke. Therefore, a longitudinal study is needed to characterize dominant mold species using DNA/RNA-based sequencing techniques and identify a causal relationship between mold exposure and allergic diseases in the future.

Improving the Indoor Air Quality in Nursery Buildings in United Arab Emirates

Children inhale indoor air at 400 mL/min∙kg per body weight, 2.76 times more than adults. They have weaker immunity than adults and are more exposed to asthma, allergies, and atopic diseases. The objective of this paper is to suggest effective management and improvement measures for indoor air quality for nurseries. As a methodology, 16 nurseries (total of 35 classrooms) were selected to measure the indoor air quality compared with WHO IAQ Standard, and identify the daily concentration change of the pollutants. Based on the measurements, IAQ improvements for selected facilities are carried out to compare the results before and after improvement. The result has shown that the concentration of Carbon Dioxide (CO₂), Total Volatile Organic Compounds (TVOC), Total Suspended Particles (TSP) and formaldehyde (CH₂O) exceeds WHO IAQ standards. The concentration of CO₂ and TSP is changed mainly by physical activity of children and that of CH₂O and TVOC is changed mainly by ventilation after school start. TVOC decreased by 46.4% and the TSP decreased by 21.7% after air purifier, but CH₂O and TVOC increased 1.8–3.8 times after interior renovation with low-emission finishing materials. After new ventilation installation, the CH₂O and TVOC reduced half and the TSP reduced one third. It is proven that the most effective way to reduce the concentration of air pollutants in nurseries is the installation of a new ventilation system, followed by an air purifier. The renovation with low-emission finishing materials cannot improve IAQ in a short period of time.

The Association Between Mercury Exposure and Atopic Dermatitis in Early Childhood: A Mothers and Children's Environmental Health Study

BACKGROUND

Atopic dermatitis is a chronic and relapsing inflammatory skin disease. Although mercury has been suggested as a risk factor, the underlying mechanism and the relationship between mercury and atopic dermatitis remains unclear. The objective of the present study was to investigate the relationship between mercury exposure and the presence of atopic dermatitis in early childhood.

METHODS

This study is part of the prospective Mothers and Children's Environmental Health cohort study. A total of 1,751 pregnant women were enrolled in Mothers and Children's Environmental Health. After delivery, children were followed up. Blood samples were collected and mothers were asked about the presence of atopic dermatitis in their children via a questionnaire at 6, 12, 24, 36, and 60 months of age.

RESULTS

After excluding participants who did not meet the inclusion criteria, a total of 1,061 mother-children pairs were included in the analysis. The geometric mean of mercury concentrations in cord blood was 5.1 µg/L. In adjusted models, cord blood mercury exposure (odds ratio [OR] = 1.1; 95% confidence interval [CI] = 1.0, 1.2 at 12-24 months) and postnatal mercury exposure (OR = 1.2; 95% CI = 1.0, 1.5 at 24-36 months, OR = 1.4; 95% CI = 1.1, 1.8 at 48-60 months) were associated with the presence of atopic dermatitis in children.

CONCLUSIONS

Postnatal mercury exposure at 24 months of age increases the risk of atopic dermatitis in children.

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

BACKGROUND

Parental history of atopic disease is a well-established risk factor for the development of atopic dermatitis (AD), but several aspects of this association remain unclear.

OBJECTIVE

We sought to determine the association of parental history of atopic disease with AD in offspring.

METHODS

We searched PubMed and EMBASE through June 2018 for relevant records and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled odds ratios (ORs) with 95% CI were calculated using random-effects models.

RESULTS

A total of 163 records covering 149 unique studies were included. Of these, 119 studies were included in the meta-analysis. Individuals with parental history of atopic disease had increased odds of AD (OR, 1.81; 95% CI, 1.65-1.99). Parental asthma (OR, 1.56; 95% CI, 1.18-2.05) and allergic rhinitis (OR, 1.68; 95% CI, 1.34-2.11) had a smaller effect than AD (OR, 3.30; 95% CI, 2.46-4.42). The effect of maternal and paternal history was comparable for all atopic diseases. An increase in odds was observed when comparing the effect of having 1 (OR, 1.30; 95% CI, 1.15-1.47) or 2 atopic parents (OR, 2.08; 95% CI, 1.83-2.36), as well as having a parent with 1 (OR, 1.49; 95% CI, 1.28-1.74) or more atopic diseases (OR, 2.32; 95% CI, 1.92-2.81).

CONCLUSIONS

This study provides evidence-based risk estimates that may guide physicians who counsel parents with a history of atopic disease about their children's risk of AD. This information is of particular importance for future efforts toward establishing prophylactic interventions for AD on a general population level.

Depressive Symptoms, Emotional Aggression, School Adjustment, and Mobile Phone Dependency Among Adolescents with Allergic Diseases in South Korea

PURPOSE

This study aimed to examine the effects of depression, aggression, and school adjustment on mobile phone dependency among South Korean adolescents, and to identify the differences in these paths among adolescents with or without allergic diseases.

DESIGN AND METHODS

The Korean Children and Youth Panel Survey, a nationwide multistage cluster sampling survey, was used for this cross-sectional study. Data were collected from 1937 first-year middle school students in South Korea, using self-reported questionnaires. Multiple-group structural equation modeling was used to test the differences of the critical ratio for the variables depressive symptom, emotional aggression, school adjustment, and mobile phone dependency between adolescents with allergic diseases and those without allergic disease.

RESULTS

Depressive symptoms and emotional aggression were significantly higher in the allergic disease group. Significantly different effects were found on the path of depressive symptoms to school adjustment and depressive symptoms to mobile phone dependency.

CONCLUSIONS

Higher depressive symptoms in allergic disease adolescents had a greater negative effect on school adjustment and a more positive effect on mobile phone dependency. Healthcare professionals need to be concerned not only with the physical symptoms of adolescents with allergic diseases but also with psychological issues, such as depression.

PRACTICE IMPLICATIONS

Early assessments and interventions for depressive symptoms in adolescents with allergic diseases could help prevent over dependency on mobile phones, as well as maladjustment to school.

Trends in the Prevalence of Childhood Asthma in Seoul Metropolitan City, Korea: The Seoul Atopy ∙ Asthma-friendly School Project

Objectives

The project Seoul Atopy ∙ Asthma-friendly School investigated the current status of childhood asthma to enable formulation of a preventative policy. We evaluated the current prevalence of childhood asthma in Seoul and its trends and related factors.

Methods

The project was conducted annually from 2011 to 2016 and involved around 35 000 children aged 1-13 years. Based on the International Study of Asthma and Allergies in Childhood guidelines, the survey involved parents. The associations of the particulate matter (PM₁₀) concentration, and the number of days on which the daily air quality guidance level was exceeded in the 25 districts of Seoul, with the prevalence of asthma were assessed.

Results

The age-standardized asthma prevalence in 2011 and 2016 was 6.74 and 4.02%, respectively. The prevalence of lifetime asthma treatment and treatment during the last 12 months tended to decrease from 2011 to 2016. Asthma treatment was significantly correlated with the number of days on which the daily air quality guidance level was exceeded, but not with the PM₁₀ concentration.

Conclusions

This study reports the prevalence of asthma among children in Seoul and confirmed the relationship between childhood asthma and known risk factors in a large-scale survey.

Association between age at asthma diagnosis and tooth loss

OBJECTIVES

This study aimed to investigate the association between age at asthma diagnosis and tooth loss due to caries using data obtained from the Korean National Health and Nutrition Examination Survey.

MATERIALS AND METHODS

A complex sample multivariable linear regression was used, and the results were analysed. Age at diagnosis and the number of teeth lost were set as independent and dependent variables, respectively. Among the total 65,973 subjects, 10,056 aged <12 years and 11,714 with missing values in dependent and independent variables were excluded. Asthmatic subjects were divided into the following age groups based on the age at diagnosis: 0-6 years, 7-12 years, 13-18 years, 19-28 years, and 29-64 years. In each analysis, the calibration was performed by adding covariates to each model.

RESULTS

Compared with the no asthma group (β = 0), the values of β in asthmatic subjects belonging to the age groups 0-6 years (β = 0.794, 0.521, 0.560) and 7-12 years (β = 0.527, 0.407, 0.437) were high in all models.

CONCLUSIONS

Our findings revealed significant increase in tooth loss due to caries after early asthma diagnosis at 0-6 years (β = 0.560, p < .001) and 7-12 years (β = 0.437, p < .001). Clinicians need to shift their perception of dental risks in young asthmatic patients and provide active oral health care to them.

Epidemiology of childhood asthma in mainland China (1988-2014): A meta-analysis

BACKGROUND

After the promotion of the two-child policy in recent years, the population of children in mainland China was bound to have a rapid growth, which would bring great challenges to public health. A number of cross-sectional studies on the epidemic of childhood asthma in mainland China were recently conducted, and varied prevalences were reported. Thus, knowing the epidemiology of childhood asthma in mainland China is of great necessity.

OBJECTIVE

Our study aimed to summarize the pooled prevalence of childhood asthma in mainland China and its time trend, gender difference, regional distribution, and age structure.

METHODS

Studies that reported the prevalence of childhood asthma in mainland China were identified via a systematic data base search through July 1, 2016. Meta-analysis was used to estimate the prevalence of childhood asthma and its subgroups, including gender, age groups, years, and regions. The regional distribution of the prevalence was set by province with the help of a geographic mapping software. The autoregressive integrated moving average model was used to predict the current prevalence of asthma.

RESULTS

A total of 117 studies published from 1988 to 2014 in mainland China with a total sample size of 2,678,696 were included. The overall current prevalence and lifetime prevalence of childhood asthma was 2.112% (95% confidence interval [CI], 1.977-2.247%) and 2.502% (95% CI, 2.166-2.838%), respectively. The difference of the prevalences between male and female patients was significant: odds ratio 1.54 (95% CI, 1.47-1.62) for the current prevalence and odds ratio 1.61 (95% CI, 1.47-1.77) for the lifetime prevalence.

CONCLUSION

The prevalence of childhood asthma in mainland China was low but has been increasing remarkably since 1998. Boys are more likely to have asthma throughout most of their childhood. Preschoolers (3-6 years old) showed a higher prevalence than the other age groups. The current prevalence of childhood asthma probably increased slightly from 2017 to 2019.

[The prevalence and risk factors of allergic rhinitis among the children of the preschool age]

The objective of the present work was to estimate the prevalence and risk factors of the development of allergic rhinitis among the children at the age from 3 to 6 years. The cross-sectional study was carried out in five cities of the Altai region during the period from 2015 to 2016. The prevalence of allergic rhinitis was evaluated with the use of the Russian language version of the ISAAC questionnaire filled up by the parents of the children. A child whose parents answered in the affirmative to the question 'Did your child have the runny nose, nasal congestion, and/or sneezing in the absence of cold symptoms and acute viral infection during the last 12 months?' were considered to be suffering from active allergic rhinitis (AAR). The risk factors for the development of this condition were identified with the use of an additional questionnaire. A total of 3205 filled questionnaires were available for the analysis. Based on the data obtained, the prevalence of active allergic rhinitis among the study population was estimated at 18.0% (n=577). 243 (42.1%) of these children presented with the symptoms of conjunctivitis. Therefore, the prevalence of active allergic rhinoconjunctivitis (ARC appears to be 7.5% (n=243). In fact, the medically verified diagnosis of allergic rhinitis was established only in 6.4% (n=204) children of the 577 ones having AAR. The family history of allergic rhinitis was shown to increase the risk of development of AAR by 2.6 times (OR=2.63 , 95%; CI=2.16-3.19; p<0.01) and that of ARC by 2.8 times (OR=2.85, 95%; CI=2.16-3.75; p<0.01). Masculine gender was found to increase the risk of development of both AAR an ARC by 1.3 times (OR=1.35, 95%; CI=1.01-1.37; p<0.05) and (OR=1.35, 95%; CI=1.03-1.76; p<0.05) respectively. The actual prevalence of active allergic rhinitis was significantly higher than the frequency of the medically verified diagnoses of this condition. It is concluded that the family history of allergic diseases and the masculine gender considerably increase the risk of development of both AAR and AFC.

Mycoplasma pneumoniae induces allergy by producing P1-specific immunoglobulin E

BACKGROUND

Our previous study found that most Mycoplasma pneumoniae (MP) pneumonia (MPP)patients had elevated serum total immunoglobulin E (IgE) levels.

OBJECTIVE

To determine components of MP that can cause an IgE increase in children, and to clarify its specific mechanism.

METHODS

The components of MP cells were isolated by serum IgE from patients with MP pneumonia. These components obtained through the prokaryotic expression were used as allergens to detect the proportion of allergen-specific IgE produced in MPP patients, and the clinical characteristics and related immune parameters of these patients who produced this allergen-specific IgE were also analyzed. In addition, a cell experiment was used to verify the biological effect of these components in vitro.

RESULTS

P1-specific IgE was detected in serum of MPP children. An approximately 24-kDa polypeptide of P1 protein was obtained through prokaryotic expression purified by nickel agarose affinity chromatography. Approximately 9.2% of MPP patients produced IgE against this polypeptide of P1 protein, which was more likely to be produced in MPP patients with no history of allergies or family history of allergy-related diseases. P1-specific IgE-positive MPP patients had more severe clinical symptoms, with excessive secretion of interleukin (IL)-4 and IL-5 and overdifferentiation of Th0 cells into Th2 cells. Tests also demonstrated that the P1 protein stimulated excessive secretion of IL-4 and IL-5 in peripheral blood mononuclear cells from the peripheral blood of healthy donors.

CONCLUSION

Mycoplasma pneumoniae is not only an infectious agent but also an allergen for certain individuals. The P1 protein of MP can induce the production of P1-specific IgE.

Time trends of the prevalence of allergic diseases in Korea: A systematic literature review

The prevalence of allergic diseases has increased dramatically in recent decades, and are now considered major chronic diseases at the global level. The increasing burden of allergic diseases has led to numerous worldwide and local researchers to investigate the time trends in its prevalence and identify its driving factors. Environmental changes such as urbanization and industrialization have been suggested to explain the increasing prevalence, but recent reports from Western countries suggest that this prevalence has reached a plateau or even possibly, started to decrease. However, such environmental changes are still occurring in many Asia-Pacific countries, including Korea, and it is speculated that the peak in allergy epidemics has yet to come. The present systematic literature review aimed to explore the time trends in the prevalence of allergic diseases in Korea and to identify the unmet needs for facilitating further studies.

Indoors and health: results of a systematic literature review assessing the potential health effects of living in basements

A new law approved in March 2017 in the Lombardy Region makes it possible to live in basements. Basements are defined as buildings partly below curb level but with at least one-half of its height above the curb. Basements' features and structural characteristics might pose risks to human health. In this paper we adopt a multidisciplinary approach to assess the potential health effects of living in basements. In particular, we define a conceptual framework to describe basements' structural characteristics which are risk factors, as well as the mechanisms through which they impact on human health. We also conduct a systematic review on the scientific databases PubMed,Embase, DOAJ, Proquest and EBSCO to retrieve, pool and critically analyze all available research that quantified the risk of living in basements for different health outcomes. Available evidence suggests living in basements increases the risk of respiratory diseases (asthma and allergic disorders); more heterogeneous data are available for cancers and cardiovascular diseases. As more quantitative data need to be prospectively retrieved to assess and monitor the risk of living in basements for human health, clear minimum requirements for light, air, sanitation and egress are to be defined by technical experts and enforced by policy makers.

Concealing Emotions at Work Is Associated with Allergic Rhinitis in Korea

Concealing emotions at work can cause considerable psychological stress. While there is extensive research on the adverse health effects of concealing emotions and the association between allergic diseases and stress, research has not yet investigated whether concealing emotions at work is associated with allergic rhinitis. Allergic rhinitis is a common disease in many industrialized countries, and its prevalence is increasing. Thus, our aim was to determine the strength of this association using data from three years (2007-2009) of the 4th Korean National Health and Nutrition Examination Survey. Participants (aged 20-64) were 8,345 individuals who were economically active and who had completed the questionnaire items on concealing emotions at work. Odds ratio (OR) and 95% confidence intervals (95% CIs) were calculated for allergic rhinitis using logistic regression models. Among all participants, 3,140 subjects (37.6%) reported concealing their emotions at work: 1,661 men and 1,479 women. The OR (95% CIs) for allergic rhinitis among those who concealed emotions at work versus those who did not was 1.318 (1.148-1.512). Stratified by sex, the OR (95% CIs) was 1.307 (1.078-1.585) among men and 1.346 (1.105-1.639) among women. Thus, individuals who concealed their emotions at work were significantly more likely to have a diagnosis of AR in comparison to those who did not. Because concealing emotions at work has adverse health effects, labor policies that aim to reduce this practice are needed.

Incident asthma and Mycoplasma pneumoniae: A nationwide cohort study

BACKGROUND

Previous studies investigating the relationship between Mycoplasma pneumoniae and incident asthma in the general population have been inconclusive.

OBJECTIVE

We conducted a nationwide cohort study to clarify this relationship.

METHODS

Using the National Health Insurance Research Database of Taiwan, we identified 1591 patients with M pneumoniae infection (International Classification of Diseases, Ninth Revision, Clinical Modification code 4830) given diagnoses between 2000 and 2008. We then frequency matched 6364 patients without M pneumoniae infection from the general population according to age, sex, and index year. Cox proportional hazards regression analysis was performed to determine the adjusted hazard ratio (aHR) of the occurrence of asthma in the M pneumoniae cohort compared with that in the non-M pneumoniae cohort.

RESULTS

Regardless of comorbidities and the use of antibiotic or steroid therapies, patients with M pneumonia infection had a higher risk of incident asthma than those without it. The aHR of asthma was 3.35 (95% CI, 2.71-4.15) for the M pneumoniae cohort, with a significantly higher risk when patients were stratified by age, sex, follow-up time, and comorbidities, including allergic rhinitis, atopic dermatitis, or allergic conjunctivitis. Patients with M pneumoniae infection had a higher risk of having early-onset (age, <12 years; aHR, 2.87) and late-onset (age, ≥12 years; aHR, 3.95) asthma. The aHR was also higher within the less than 2-year follow-up in the M pneumoniae cohort (aHR, 4.41; 95% CI, 3.40-5.74) than in the cohort without the infection.

CONCLUSION

This study found that incident cases of early-onset and late-onset asthma are closely related to M pneumoniae infection, even in nonatopic patients.

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

The purpose of this study was to explore risk factors related to asthma prevalence among preschool and school-aged children using a representative national dataset from the Korea National Health and Nutrition Examination Survey (KNHANES) conducted from 2009–2011. We evaluated the demographic information, health status, household environment, socioeconomic status, and parents’ health status of 3,542 children aged 4–12 years. A sex-stratified multivariate logistic regression was used to obtain adjusted prevalence odds ratios (ORs) and 95% confidence intervals after accounting for primary sample units, stratification, and sample weights. The sex-specific asthma prevalence in the 4- to 12-year-old children was 7.39% in boys and 6.27% in girls. Boys and girls with comorbid atopic dermatitis were more likely to have asthma than those without atopic dermatitis (boys: OR = 2.20, p = 0.0071; girls: OR = 2.33, p = 0.0031). Boys and girls with ≥1 asthmatic parent were more likely to have asthma than those without asthmatic parents (boys: OR = 3.90, p = 0.0006; girls: OR = 3.65, p = 0.0138). As girls got older, the prevalence of asthma decreased (OR = 0.90, p = 0.0408). Girls residing in rural areas were 60% less likely to have asthma than those residing in urban areas (p = 0.0309). Boys with ≥5 family members were more likely to have asthma than those with ≤3 family members (OR = 2.45, p = 0.0323). The factors related to asthma prevalence may differ depending on sex in preschool and school-aged children. By understanding the characteristics of sex-based differences in asthma, individualized asthma management plans may be established clinically.

Indoor total volatile organic compounds exposure at 6 months followed by atopic dermatitis at 3 years in children

BACKGROUND

Exposure to indoor air pollutants is thought to cause allergic inflammation. Volatile organic compounds (VOCs) are one of the aggravating factors of asthma and other allergic diseases. However, the influence of VOCs on development of atopic dermatitis is ambiguous in the clinical field. We therefore investigated the associations of indoor total volatile organic compounds (TVOCs) and development of atopic dermatitis in young Korean children.

METHODS

From the birth cohort of a MOthers and Children's Environmental Health (MOCEH) study, 257 infants, whose parents agreed with the environmental measurement, were enrolled. Total VOCs were measured in infant's bedrooms at the age of 6 month. A total of 105 parents answered a questionnaire at 36 month. Concentrations of TVOCs were divided into two groups by third quartile (75th). Associations between the high VOCs exposure group and development of atopic dermatitis at the age of 36 months were estimated by multivariate logistic regression.

RESULTS

The average concentration of TVOCs was 174.7 ± 115.1 ㎍/m(3) . We defined the high TVOCs exposure group by those with more than 75 percentile of the distribution (242.1 ㎍/m(3) ). An increased risk of atopic dermatitis was observed in the high TVOCs exposure group, after adjustment for parents history of allergy, household income, breast-feeding longer than 6 month (OR = 3.116, 95% Cl 1.041-9.323). Risk of atopic dermatitis was increased when the family bought new furniture within 1 yr.

CONCLUSION

Our results showed that exposure to high concentration of VOCs during infancy, an indoor pollutant, increased the risk of atopic dermatitis at 36 months.