Impact of Environmental Factors on the Prevalence Changes of Allergic Diseases in Elementary School Students in Ulsan, Korea: A Longitudinal Study

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.

Assessment of fungal contamination and biosecurity risk factors in duck-breeding farms in South Korea

Fungi are pathogens that infect all types of poultry and farmers, leading to economic losses in poultry production. Fungi can be isolated from environmental samples and are ubiquitous in the air. This study aimed to evaluate fungal contamination in domestic duck farm environments and analyze biosecurity risk factors associated with fungal infection incidence to assess the vulnerability of the farms to fungal infection. The average fungal concentration was 203 colony-forming units (CFU)/m3 in the air and 365 × 103 CFU/m2 in the wall surface samples. Sixteen fungal genera were recovered from air and wall surface samples from 19 duck-breeding farms, Aspergillus being the most frequently isolated (air: 43.2%; wall surface: 40%). Eleven additional fungal genera (Acrophialophora, Byssochlamys, Fusarium, Lichtheimia, Paecilomyces, Penicillium, Polycephalomyces, Rhizomucor, Scopulariopsis, Talaromyces, and Thermoascus) were isolated from air samples. Also, 8 additional fungal genera (Chaetomium, Lichtheimia, Penicillium, Petriella, Rhizomucor, Rhizopus, Talaromyces, and Trichosporon) were isolated from wall surface samples. The characteristics of the poultry farms (geographic region, stocking density, breeding house type, affiliate, duck age, and season) and fungal concentrations in the air and wall surface samples were analyzed to evaluate the biosecurity risk of the farms. Fungal infections were significantly affected by high stocking density (>2 ducks/m2), duck age (18-25 wk and >60 wk), and high fungal concentration in the wall surface samples (>300 × 103 CFU/m2).

Global warming and implications for epithelial barrier disruption and respiratory and dermatologic allergic diseases

Global warming has direct and indirect effects, as well as short- and long-term impacts on the respiratory and skin barriers. Extreme temperature directly affects the airway epithelial barrier by disrupting the structural proteins and by triggering airway inflammation and hyperreactivity. It enhances tidal volume and respiratory rate by affecting the thermoregulatory system, causing specific airway resistance and reflex bronchoconstriction via activation of bronchopulmonary vagal C fibers and upregulation of transient receptor potential vanilloid (TRPV) 1 and TRPV4. Heat shock proteins are activated under heat stress and contribute to both epithelial barrier dysfunction and airway inflammation. Accordingly, the frequency and severity of allergic rhinitis and asthma have been increasing. Heat activates TRPV3 in keratinocytes, causing the secretion of inflammatory mediators and eventually pruritus. Exposure to air pollutants alters the expression of genes that control skin barrier integrity and triggers an immune response, increasing the incidence and prevalence of atopic dermatitis. There is evidence that extreme temperature, heavy rains and floods, air pollution, and wildfires increase atopic dermatitis flares. In this narrative review, focused on the last 3 years of literature, we explore the effects of global warming on respiratory and skin barrier and their clinical consequences.

Association between exposure to air pollution and risk of allergic rhinitis: A systematic review and meta-analysis

BACKGROUND

Allergic rhinitis (AR) is one of the most common allergic diseases in the world, and usually persists throughout the activity. Epidemiological studies have shown a positive association between air pollution and allergic rhinitis. However, we could not find any meta-analysis of the risk of air pollutants (PM_2.5, PM₁₀, NO₂, SO₂, O₃ and CO) on the prevalence of AR in people of all ages.

OBJECTIVES

Carry out a meta-analysis on the results of recent studies (up to 2020) to present valid information about exposure to air pollution and risk of prevalence of AR.

METHODS

We systematically searched three databases for studies up to December 17, 2020, including air pollution and AR. Random effect models were conducted to estimate the pooled odds ratios (ORs) and 95% confidence intervals (95% CIs). Subgroup analysis, funnel plot, Egger's test, and the trim-and-fill method were also conducted.

RESULTS

Thirty-five studies across 12 countries, including a total of 453,470 participants, were included. The OR per 10 μg/m³ increase of pollutants was 1.13 (1.04-1.22) for PM₁₀ and 1.12 (1.05-1.20) for PM_2.5. The OR per 10 μg/m³ increment of gaseous pollutants were 1.13 (1.07-1.20) for NO₂, 1.13 (1.04-1.22) for SO₂ and 1.07 (1.01-1.12) for O₃. No significant association was observed between CO and AR. Children or adolescents are more sensitive to air pollution than adults. The effects of PM₁₀ and SO₂ were significantly stronger in Europe than Asia. The effects of air pollutants were more significant and higher in developing countries than in developed countries, except for PM₁₀. A significant difference of subgroup test was found between developed and developing countries of NO₂.

CONCLUSION

This meta-analysis showed a positive association between air pollution and the prevalence of allergic rhinitis, and identified geographic area and economic level as the potential modifiers for the association.

Effects of rosmarinic acid on the inflammatory response in allergic rhinitis rat models after PM2.5 exposure

BACKGROUND

Studies have shown the promising prospects of rosmarinic acid (RosA) for the prevention and treatment of allergic diseases.

OBJECTIVE

The aim of this study was to investigate the effects of RosA on inflammatory reaction in rat models of allergic rhinitis (AR) after PM2.5 exposure.

METHODS

Allergic rhinitis rat models were established by ovalbumin sensitization, and PM2.5 was applied at a concentration of 1000 μg/m3 , 3 h a day for 30 consecutive days. RosA was administered via intraperitoneal injection (20 mg/kg/d) for seven consecutive days. Allergic nasal symptoms were recorded. The expressions of interleukin (IL)-4, IL-13, interferon (INF)-γ, and OVA-sIgE were determined by ELISA. Histopathological changes in nasal mucosa were observed by HE staining. mRNA expressions of T-bet and GATA-3 in nasal mucosa were detected by RT-PCR. NF-κBp65 in cell nuclei and IκBα in cytoplasm were analyzed by Western blot.

RESULTS

PM2.5 exposure worsened allergic nasal symptoms in AR rats, while RosA ameliorated these symptoms. Histopathologically, AR rats exhibited disorganized nasal mucosal epithelium, cell exfoliation, eosinophilic infiltration of lamina propria, gland swelling, and submucosal vascular congestion, which were aggravated by PM2.5 exposure and alleviated by RosA. RosA decreased the expressions of IL-4, IL-13, and increased the level of IFN-γ in PM2.5-exposed AR rats. After RosA intervention, the expressions of GATA-3 mRNA and NF-κBp65 in PM2.5-exposed AR rats were significantly reduced, while those of T-bet mRNA and IκBα were markedly increased.

CONCLUSION

Rosmarinic acid may alleviate symptoms of AR rat models exposed to PM2.5 through the modulation of the NF-κB pathway and Th1/Th2 balance.