Residential Risk Factors for Atopic Dermatitis in 3- to 6-Year Old Children: A Cross-Sectional Study in Shanghai, China

[Medical clinical diagnostics for indoor mould exposure - Update 2023 (AWMF Register No. 161/001)]

This article is an abridged version of the updated AWMF mould guideline "Medical clinical diagnostics in case of indoor mould exposure - Update 2023", presented in July 2023 by the German Society of Hygiene, Environmental Medicine and Preventive Medicine (Gesellschaft für Hygiene, Umweltmedizin und Präventivmedizin, GHUP), in collaboration with German and Austrian scientific medical societies, and experts. Indoor mould growth is a potential health risk, even if a quantitative and/or causal relationship between the occurrence of individual mould species and health problems has yet to be established. There is no evidence for a causal relationship between moisture/mould damage and human diseases, mainly because of the ubiquitous presence of fungi and hitherto inadequate diagnostic methods. Sufficient evidence for an association between moisture/mould damage and the following health effects has been established for: allergic respiratory diseases, allergic rhinitis, allergic rhino-conjunctivitis, allergic bronchopulmonary aspergillosis (ABPA), other allergic bronchopulmonary mycosis (ABPM), aspergilloma, Aspergillus bronchitis, asthma (manifestation, progression, exacerbation), bronchitis (acute, chronic), community-acquired Aspergillus pneumonia, hypersensitivity pneumonitis (HP; extrinsic allergic alveolitis (EEA)), invasive Aspergillosis, mycoses, organic dust toxic syndrome (ODTS) [workplace exposure], promotion of respiratory infections, pulmonary aspergillosis (subacute, chronic), and rhinosinusitis (acute, chronically invasive, or granulomatous, allergic). In this context the sensitizing potential of moulds is obviously low compared to other environmental allergens. Recent studies show a comparatively low sensitization prevalence of 3-22,5 % in the general population across Europe. Limited or suspected evidence for an association exist with respect to atopic eczema (atopic dermatitis, neurodermatitis; manifestation), chronic obstructive pulmonary disease (COPD), mood disorders, mucous membrane irritation (MMI), odor effects, and sarcoidosis. (iv) Inadequate or insufficient evidence for an association exist for acute idiopathic pulmonary hemorrhage in infants, airborne transmitted mycotoxicosis, arthritis, autoimmune diseases, cancer, chronic fatigue syndrome (CFS), endocrinopathies, gastrointestinal effects, multiple chemical sensitivity (MCS), multiple sclerosis, neuropsychological effects, neurotoxic effects, renal effects, reproductive disorders, rheumatism, sick building syndrome (SBS), sudden infant death syndrome, teratogenicity, thyroid diseases, and urticaria.The risk of infection posed by moulds regularly occurring indoors is low for healthy persons; most species are in risk group 1 and a few in risk group 2 (Aspergillus fumigatus, A. flavus) of the German Biological Agents Act (Biostoffverordnung). Only moulds that are potentially able to form toxins can be triggers of toxic reactions. Whether or not toxin formation occurs in individual cases is determined by environmental and growth conditions, water activity, temperature and above all the growth substrates.In case of indoor moisture/mould damage, everyone can be affected by odor effects and/or mood disorders.However, this is not an acute health hazard. Predisposing factors for odor effects can include genetic and hormonal influences, imprinting, context and adaptation effects. Predisposing factors for mood disorders may include environmental concerns, anxiety, condition, and attribution, as well as various diseases. Risk groups to be protected particularly regarding infection risk are immunocompromised persons according to the classification of the German Commission for Hospital Hygiene and Infection Prevention (Kommission für Krankenhaushygiene und Infektionsprävention, KRINKO) at the Robert Koch-Institute (RKI), persons suffering from severe influenza, persons suffering from severe COVID-19, and persons with cystic fibrosis (mucoviscidosis); with regard to allergic risk, persons with cystic fibrosis (mucoviscidosis) and patients with bronchial asthma must be protected. The rational diagnostics include the medical history, physical examination, and conventional allergy diagnostics including provocation tests if necessary; sometimes cellular test systems are indicated. In the case of mould infections, the reader is referred to the specific guidelines. Regarding mycotoxins, there are currently no useful and validated test procedures for clinical diagnostics. From a preventive medical point of view, it is important that indoor mould infestation in relevant magnitudes cannot be tolerated for precautionary reasons.For evaluation of mould damage in the indoor environment and appropriate remedial procedures, the reader is referred to the mould guideline issued by the German Federal Environment Agency (Umweltbundesamt, UBA).

AWMF mold guideline "Medical clinical diagnostics for indoor mold exposure" - Update 2023 AWMF Register No. 161/001

None.

Atopic Dermatitis: Disease Background and Risk Factors

Multiple risk factors have been associated with the development of atopic dermatitis (AD). Recent advances in understanding the role of genetics in this disease have been made, with discovery of the filaggrin (FLG) gene as the most notable so far. In addition to FLG gene mutations as a risk factor for AD, a positive family history of atopic or allergic disease in either parent has been shown to confer a greater risk of developing AD. Atopic dermatitis usually presents early in life and is thought to represent the initial step in the "atopic march," which is characterized by the development of other atopic diseases later in life such as asthma, allergic rhinitis, and/or rhinoconjunctivitis, food allergies, and hay fever. Other comorbid diseases that have been associated with AD include increase risk of viral and bacterial skin infections, neuropsychiatric diseases such as attention-deficit hyperactivity disorders (ADHD), and autistic spectrum disorder (ASD). Patients with AD have also been found to have worse sleep quality overall compared to patients without AD. In this chapter, we will discuss the risk factors associated with development of atopic dermatitis as well as the most commonly reported comorbidities in patients with this disease.

Associations between home environmental factors and childhood eczema and related symptoms in different cities in China

Previous studies have shown significant associations between home environmental factors and childhood eczema. However, few studies have compared how associations differ in different regions. This study investigated associations between home environmental factors and childhood eczema ever, and related symptoms including itchy rash (IR) and being awakened by itchy rash at night (awake by IR) in 4 cities located in different regions of China, based on cross-sectional investigations during 2010-2012. We used two-step analysis to explore the associations between influencing factors and eczema/related symptoms: first, group Least Absolute Shrinkage and Selection Operator (LASSO) was conducted to identify important factors among a list of candidates; then, the associations in total study population and in each city were estimated using logistic regression. We found these home environmental factors to be risk factors for eczema or related symptoms: large residence size, shared room, air cleaner at home, abnormal smell, perceived dry air, visible mold or damp stains, cooking with coal or wood, painted wall, incense, mice, new furniture during pregnancy, abnormal smell at birth, window condensation at birth and environmental tobacco smoke at birth. Environmental protective factors were rural house location and window ventilation. Associations of factors with eczema/related symptoms differed across cities. For example, air conditioning was protective for eczema in Beijing and awakening by IR in Shanghai with ORs of 0.70 (95%CI: 0.52, 0.95) and 0.33 (95%CI: 0.14, 0.81) respectively, but not significant in other cities. Our results have implications for improving home environments to reduce the risk of childhood eczema/related symptoms in different regions of China.

Regional Differences in the Prevalence of Atopic Dermatitis among Schoolchildren in Japan and Its Associated Factors from 2006 to 2018

The trends in the prevalence of atopic dermatitis for each prefecture over recent years have not been investigated in Japan, and no studies investigating the factors associated with the prevalence using nationwide data have been conducted. We investigated the trends in the prevalence of atopic dermatitis among schoolchildren for each prefecture in Japan from 2006 to 2018 and identified the factors associated with regional differences in prevalence. The data on the atopic dermatitis prevalence in schoolchildren aged 6–17 years were collected as part of the School Health Statistics Research. The demographic, socioeconomic, medical, and environmental characteristics of the prefectures were examined for possible associations with the prevalence. The age-standardized prevalence rates of atopic dermatitis were calculated separately for boys and girls and by prefecture and year. We examined the associations between the age-standardized prevalence rates and prefectural characteristics using an ecological study. The age-standardized prevalence rates of atopic dermatitis tended to be stable for Japan as a whole, whereas the trend in the age-standardized prevalence rates differed across prefectures. In the regression analysis, the year was negatively associated and the number of medical clinics per 100,000 persons was positively associated with the age-standardized prevalence in girls. The taxable income per capita was positively associated with the age-standardized prevalence both in boys and in girls.

The prevalence and year lived with disability of atopic dermatitis in China: Findings from the global burden of disease study 2019

Background

Atopic dermatitis (AD) is a chronic disease with growing prevalence and has become a global public health problem. However, little is known about the burden caused by AD in China.

Objective

To access the prevalence and burden of AD in China.

Methods

We estimated the prevalence and year lived with disability (YLD) of AD in China, by different age and sex groups. We also compared the burden of AD in China with other countries in the Group of Twenty (G20). We analyzed the changes in the number of AD patients and their YLDs by cause decomposition from 1990 to 2019.

Results

AD was the twenty-fourth leading cause of the burden of 369 diseases in China in 2019. From 1990 to 2019, the age-standardized prevalence and YLD rate of AD in China increased by 1.04% and 1.43% respectively, which were the second and the largest increase among the G20 and both higher than the global average (-4.29% and -4.14%). The number of patients with AD increased by 25.65%, of which 20.16% was due to population growth, 3.85% due to population aging, and 1.64% due to age-specific prevalence. Both the prevalence and YLD rate of AD were higher in 1 to 4 year-olds and 95+ years age group. Before the age of 10, the prevalence and YLD rate of AD in males were higher than those in females, while there was a marked sex shift at the ages of 10 to 14.

Conclusion

AD is a serious public health problem in China. Substantial variations exist in burden due to AD between male and female, and in age groups. Considering these findings will be important for developing preventive strategies and treatments to reduce the burden of AD.

Prenatal paraben exposure and atopic dermatitis-related outcomes among children

BACKGROUND

Parabens, widely used as preservatives in cosmetics, foods, and other consumer products, are suspected of contributing to allergy susceptibility. The detection of parabens in the placenta or amniotic fluid raised concerns about potential health consequences for the child. Recently, an increased asthma risk following prenatal exposure has been reported. Here, we investigated whether prenatal paraben exposure can influence the risk for atopic dermatitis (AD).

METHODS

261 mother-child pairs of the German mother-child study LINA were included in this analysis. Eight paraben species were quantified in maternal urine obtained at gestational week 34. According to the parental report of physician-diagnosed AD from age 1 to 8 years, disease onset, and persistence, childhood AD was classified into four different phenotypes.

RESULTS

4.6% (n = 12) and 12.3% (n = 32) of the children were classified as having very early-onset AD (until age two) either with or without remission, 11.9% (n = 31) as early-onset (after age two), and 3.1% (n = 8) as childhood-onset AD (after age six). Exposure to ethylparaben and n-butylparaben was associated with an increased risk to develop very early-onset AD without remission (EtP: adj.OR/95% CI:1.44/1.04-2.00,nBuP:adj.OR/95% CI:1.95/1.22-3.12). The effects of both parabens were predominant in children without a history of maternal AD and independent of children's sex.

CONCLUSION

Prenatal EtP or nBuP exposure may increase children's susceptibility for persistent AD with disease onset at very early age. This association was particularly pronounced in children without a history of maternal AD, indicating that children without a genetic predisposition are more susceptible to paraben exposure.

Prenatal and Perinatal Environmental Influences Shaping the Neonatal Immune System: A Focus on Asthma and Allergy Origins

It is suggested that programming of the immune system starts before birth and is shaped by environmental influences acting during critical windows of susceptibility for human development. Prenatal and perinatal exposure to physiological, biological, physical, or chemical factors can trigger permanent, irreversible changes to the developing immune system, which may be reflected in cord blood of neonates. The aim of this narrative review is to summarize the evidence on the role of the prenatal and perinatal environment, including season of birth, mode of delivery, exposure to common allergens, a farming environment, pet ownership, and exposure to tobacco smoking and pollutants, in shaping the immune cell populations and cytokines at birth in humans. We also discuss how reported disruptions in the immune system at birth might contribute to the development of asthma and related allergic manifestations later in life.

A systematic review and meta-analysis of risk factors associated with atopic dermatitis in Asia

Background

Atopic dermatitis (AD) is a chronic, inflammatory skin disorder characterised by intense itch and eczematous lesions. Rising prevalence of AD has been observed worldwide including in Asia. Understanding the risk factors associated with AD may explain its pathogenicity and identify new preventive strategies and treatments. However, AD-associated risk factors and comorbidities specific to Asia have not been systematically reviewed.

Methods

We performed a systematic review in accordance with the Preferred Reporting Item for Systematic Review and Meta-Analyses (PRISMA) guidelines and summarised epidemiological studies investigating personal, family, and environmental factors and comorbidities associated with AD in Asia. Significant factors were assessed if they can be altered through lifestyle practices and further classified into non-modifiable and modifiable factors. Meta-analysis using the random-effect model was also conducted to provide an overall estimate for several significant factors.

Results

We identified a total of 162 epidemiological studies conducted in Asia. Among non-modifiable factors, a family history of atopic diseases was the most reported, suggesting the involvement of genetics in AD pathogenesis. Among modifiable factors, the results of meta-analyses revealed maternal smoking as the strongest risk factor with a pooled odds ratio (OR) of 2.95 (95% CI, 2.43-3.60), followed by active smoking (pooled OR, 1.91, 95% CI, 1.41-2.59).

Conclusion

While a family history may aid clinicians in identifying high-risk individuals, literature has long suggested the importance of gene-environment interaction. This review identified several modifiable factors including medical treatments, indoor and outdoor environmental exposure, and personal and family lifestyle specific to Asia. Based on the meta-analyses performed, prevention strategies against AD may start from changing personal and family lifestyle choices, especially smoking habits.

Early-life exposure to air pollution and childhood allergic diseases: an update on the link and its implications

INTRODUCTION

Although mounting evidence has linked environmental factors with childhood allergies, some specific key issues still remain unclear: what is the main environmental factor? what is the critical timing window? And whether these contribute to the development of disease?

AREAS COVERED

This selective review summarizes recent epidemiological studies on the association between early-life exposure to indoor/outdoor air pollution and childhood allergic diseases. A literature search was conducted in the PubMed and Web of Science for peer-reviewed articles published until April 2020. Exposure to the traffic-related air pollutant, NO₂, exposure during pregnancy and early postnatal periods is found to be associated with childhood allergies, and exposure during different trimesters causes different allergic diseases. However, exposure to classical air pollutants (PM₁₀ and SO₂) also contributes to childhood allergy in developing countries. In addition, early-life exposure to indoor renovation and mold/dampness significantly increases the risk of allergy in children. A synergistic effect between indoor and outdoor air pollution is found in the development of allergic diseases.

EXPERT OPINION

Early-life exposure to outdoor air pollution and indoor environmental factors plays an important role in the development of childhood allergic diseases, and the synergy between indoor and outdoor exposures increases allergy risk. The available findings support the hypothesis of the 'fetal origins of childhood allergy,' with new implications for the effective control and early prevention of childhood allergies.

Allergy-related disorders (ARDs) among Ethiopian primary school-aged children: Prevalence and associated risk factors

Background

There has been a noticeable increase in the prevalence of allergy-related disorders (ARDs) in the modern era. Urbanization is believed to be a major environmental risk factor for the onset of ARDs but data from low- to middle-income countries is limited.

Objective

Our purpose was to assess the prevalence of ARDs and atopy among a population of rural Ethiopian school children and identify environmental and lifestyle factors associated with such disorders.

Methods

We performed a cross-sectional study on 541 school-children. An interviewer-led questionnaire administered to the mothers of each participant provided information on demographic and lifestyle variables. Questions on allergic disease symptoms were based on the International Study of Asthma and Allergies in Children (ISAAC) core allergy and environmental questionnaire. Skin prick test for common allergens German cockroach (Blattella germanica) and dust mite (Dermatophagoides) was performed to define atopy. Multiple logistic regression analyses were performed to determine the odds ratio between ARDs and atopy with specific environmental and lifestyle habits.

Results

541 children responded to the survey questions: the majority of participants were female (60.3%) and aged 10–15 years-old. The prevalence of any ARD was 27%, while the rates of ever-having eczema, rhinitis, and wheeze was found to be 16.8%, 9.6%, and 8.6% respectively. Only 3.6% (19 school-children) tested positive for any skin sensitization. Analysis of associated factors for ARDs found that a family history of allergic disorders (AOR: 2.80; p-value<0.01), use of insecticides (AOR: 2.05; p-value<0.01), and wearing open-toed shoes (AOR: 2.19; p-value = 0.02) were all significantly associated factors. Insecticide use, river-bathing, and infection with intestinal parasites were found to be significantly associated factors for atopy. Other potential risk factors such as frequent use of soap, bacterial infection, and household crowding had no statistical significance.

Conclusion

Our study suggests that the prevalence of skin sensitization and ARDs in rural populations of developing countries is still relatively low. We identified several possible risk factors for further investigation. Overall, the significance of identified risk factors appears to indicate that genetic predisposition and exposure to environmental pollution are more important to the etiology of ARDs and atopy than specific lifestyle behaviors.

Atopic Dermatitis: Disease Background and Risk Factors

Multiple risk factors have been associated with the development of atopic dermatitis (AD). Recent advances in understanding the role of genetics in this disease have been made, with discovery of the filaggrin (FLG) gene as the most notable so far. In addition to FLG gene mutations as a risk factor for AD, a positive family history of atopic or allergic disease in either parent, has been shown to confer a greater risk of developing AD. Atopic dermatitis usually presents early in life and is thought to represent the initial-step in the "atopic march" which is characterized by the development of other atopic diseases later in life such as asthma, allergic rhinitis and/or rhinoconjunctivitis, food allergies and hay fever. Other comorbid diseases that have been associated with AD include increase risk of viral and bacterial skin infections, neuropsychiatric diseases such as attention-deficit hyperactivity disorders (ADHD) and autistic spectrum disorder (ASD). Patients with AD, have also been found to have worse sleep quality overall compared to patients without AD. In this chapter, we will discuss the risk factors associated with development of atopic dermatitis as well as the most commonly reported comorbidities in patients with this disease.