Indoor environmental factors associated with wheezing illness and asthma in South Korean children: phase III of the International Study of Asthma and Allergies in Childhood

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.

Preschoolers with recurrent wheezing have a high prevalence of sleep disordered breathing

Objective: Sleep-disordered breathing (SDB) is highly prevalent in school children with poorly-controlled asthma. However, this association has not been assessed in preschoolers with recurrent wheeze, nor in those at risk for asthma. We hypothesized that preschoolers with asthma risk (positive asthma predictive index [API]) have a higher prevalence of SDB and higher inflammatory biomarkers (blood-hsCRP and urinary-LTE4) levels than those with negative API.Method: Children 2 to 5 years of age with recurrent wheezing were classified as positive or negative API. SDB was determined by the pediatric sleep questionnaire (PSQ) and its subscale (PSQSub6). Demographic characteristics, spirometry, blood hsCRP and urinary LTE4 were assessed.Results: We enrolled 101 preschoolers: 70 completed all measurements, 55.4% were males, mean age 4.07 ± 0.87 years, 45% overweight or obese, 70% had positive API, 87.5% had rhinitis. The prevalence of SDB measured by PSQ was 40.8% and by PSQSub6 was 29.6%. However, the proportion of SDB was similar between positive and negative API groups. The hsCRP (mean ± SD) was higher in the positive than in negative API (3.58 ± 0.58 and 1.32 ± 0.36 mg/L, p = 0.69, respectively); moreover, no differences in urinary LTE4 were found between groups. No correlation of PSQ (+) or PSQSub6 (+) with hsCRP and uLTE4 was found. However, preschoolers with positive API had significantly more post-bronchodilator percentage change in FEF25-75 than negative API (24.14 ± 28.1 vs. 4.13 ± 21.8, respectively, p = 0.01).Conclusions: In preschoolers with recurrent wheezing, we should be investigating for the coexistence of SDB, using early screening methods for detecting those conditions.

Local Atopy in Childhood Adenotonsillar Hypertrophy

Background Although the cause of adenotonsillar hypertrophy remains unknown, some studies have shown that allergy may be a risk factor. Purpose This study determined the levels of allergen-specific immunoglobulin E (sIgE) in the adenotonsillar tissues of children with adenotonsillar hypertrophy and evaluated the clinical significance of local atopy in adenotonsillar tissues. Methods We measured 21 types of specific immunoglobulin E in the serum and adenotonsillar tissues of 102 children with adenotonsillar hypertrophy and compared the sensitization patterns of the serum and local tissues. The patients were divided into three groups-atopy, local atopy, and nonatopy-according to the sensitization of serum and adenotonsillar tissues, and the clinical symptoms among the groups were analyzed. Results Seventy-two (70.6%) children with adenotonsillar hypertrophy were sensitized to more than one allergen in the serum and/or adenotonsillar tissue. Thirty (29.4%) children had no IgE positivity to any allergen in both serum and adenotonsillar tissues. Fifty-five (53.9%) were sensitized to at least one allergen in the serum. Seventy (68.6%) were sensitized to at least one allergen in the adenotonsillar tissue. Seventeen (36.2%) of 47 children with specific immunoglobulin E-negative serum had specific immunoglobulin E-positive adenotonsillar tissues. The rate of specific immunoglobulin E was significantly higher in local tissues than in serum. The rate of inhalant allergen specific immunoglobulin E was significantly higher in the adenoids than in the tonsils. However, the rate of food allergen specific immunoglobulin E was significantly higher in the tonsils than adenoids. The lifetime prevalence of asthma and allergic rhinitis, recent symptoms or treatment of allergic rhinitis, and severity of nasal symptoms (rhinorrhea, sneezing, and nasal itching) were significantly higher in children with local atopy than with nonatopy. Conclusions These results confirm that allergic response may be a risk factor for adenotonsillar hypertrophy. Local allergic inflammation may play an important role in childhood adenotonsillar hypertrophy, and local atopy in adenotonsillar tissues can cause respiratory allergic symptoms in children.

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.

Reference Values and Utility of Serum Total Immunoglobulin E for Predicting Atopy and Allergic Diseases in Korean Schoolchildren

The present study aimed to investigate the distribution of total serum immunoglobulin E (IgE) levels in Korean schoolchildren and to evaluate its utility in the prediction of atopy and allergic diseases. A nationwide, cross-sectional survey was conducted in first grade students from randomly selected elementary and middle schools. Total IgE levels were measured by ImmunoCAP. Skin prick tests were performed for 18 common inhalant allergens to determine the presence of atopy. Children aged 12-13 years and parents of children aged 6-7 years were asked to complete questionnaire assessing allergic diseases. The cut-off levels of total IgE were determined by analyzing receiver operating characteristic curves. The median total IgE level was 86.7 kU/L (range: 1.5-4,523.1) in 3,753 children aged 6-7 years and 94.7 kU/L (range: 1.5-3,000.0) in 3,930 children aged 12-13 years. Total IgE concentrations were higher in children with atopy or allergic diseases than in those without (all P < 0.001). At the cut-off value of 127.7 kU/L, sensitivity, specificity, and positive and negative predictive values (PPV and NPV) were 67.1%, 75.4%, 65.4%, and 76.7%, respectively, in elementary schoolchildren. At the cut-off value of 63.0 kU/L, sensitivity, specificity, PPV, and NPV were 81.9%, 66.6%, 75.0%, and 75.1%, respectively, in middle schoolchildren. PPV and NPV were ≥ 70% when cut-offs of 258.8 kU/L and 38.4 kU/L were used for the diagnosis of atopy in 6-7 year-olds and 12-13 year-olds, respectively. This nationwide population-based study provided the first normal reference ranges of total IgE in Korean schoolchildren.