Are Environmental Factors for Atopic Eczema in ISAAC Phase Three due to Reverse Causation?

Environmental Influences on Atopic Eczema

The health outcomes of an individual are shaped by a combination of genetic predisposition and environmental influences. While some diseases stem solely from environmental factors, others like atopic eczema, also known as neurodermatitis or atopic dermatitis, are multifaceted, with environmental variables playing a significant role in its initiation and severity. Atopic eczema is a prevalent chronic condition observed globally, particularly in Western industrialized nations where its prevalence is estimated to range from 2.5% to 3.5% in adults and 10% to 15% among children. The increasing incidence of atopic eczema in industrialized countries over recent decades suggests that this trend may be due to environmental changes rather than genetic predispositions. Therefore, by thoroughly examining environmental factors and their role in atopic dermatitis, one may be able to gain a better understanding of its disease pattern and develop possible preventative measures. This article provides a comprehensive analysis of how the surrounding environment contributes to the pathogenesis of atopic eczema.

Benvitimod Inhibits IL-4- and IL-13-Induced Tight Junction Impairment by Activating AHR/ARNT Pathway and Inhibiting STAT6 Phosphorylation in Human Keratinocytes

Tight junctions are involved in skin barrier functions. In this study, the expression of CLDN1, CLDN4, and OCLN was found to decrease in skin lesions of atopic dermatitis by bioinformatics analysis. Immunohistochemistry staining in skin specimens from 12 patients with atopic dermatitis and 12 healthy controls also showed decreased CLDN1, CLDN4, and OCLN expression in atopic dermatitis lesions. In vitro studies showed that IL-4 and IL-13 downregulated CLDN1, CLDN4, and OCLN expression in HaCaT cells as well as CLDN4 and OCLN expression in human primary keratinocytes. This effect, which was mediated through the Jak-signal transducer and activator of transcription 6 signaling pathway, increased paracellular flux of 4-kDa dextran. Benvitimod, a new drug for atopic dermatitis, upregulated CLDN4 and OCLN through the aryl hydrocarbon receptor/aryl hydrocarbon receptor nuclear translocator pathway. Benvitimod induced nuclear translocation of NRF2 and reduced production of ROS in keratinocytes, thus inhibiting IL-4-/IL-13-induced CLDN1 downregulation and signal transducer and activator of transcription 6 phosphorylation. These results indicate that T helper 2 cytokines are involved in tight junction impairment, and benvitimod can inhibit these effects.

The immunological and structural epidermal barrier dysfunction and skin microbiome in atopic dermatitis-an update

Atopic dermatitis (AD) is a common, chronic and relapsing inflammatory skin disease with various clinical presentations and combinations of symptoms. The pathophysiology of AD is complex and multifactorial. There are several factors involved in the etiopathogenesis of AD including structural and immunological epidermal barrier defect, imbalance of the skin microbiome, genetic background and environmental factors. Alterations in structural proteins, lipids, proteases, and their inhibitors, lead to the impairment of the stratum corneum which is associated with the increased skin penetration and transepidermal water loss. The elevated serum immunoglobulin E levels and blood eosinophilia have been shown in the majority of AD patients. Type 2 T-helper cell immune pathway with increased expression of interleukin (IL)-4, IL-5, and IL-13, has an important role in the etiopathogenesis of AD. Both T cells and keratinocytes contribute to epidermal barrier impairment in AD via a dynamic interaction of cytokines and chemokines. The skin microbiome is another factor of relevance in the etiopathogenesis of AD. It has been shown that during AD flares, Staphylococcus aureus (S. aureus) colonization increased, while Staphylococcus epidermidis (S. epidermidis) decreased. On the contrary, S. epidermidis and species of Streptococcus, Corynebacterium and Propionibacterium increased during the remision phases. However, it is not clear whether skin dysbiosis is one of the symptoms or one of the causes of AD. There are several therapeutic options, targeting these pathways which play a critical role in the etiopathogenesis of AD. Although topical steroids are the mainstay of the treatment of AD, new biological therapies including IL-4, IL-13, and IL-31 inhibitors, as well as Janus kinase inhibitors (JAKi), increasingly gain more importance with new advances in the therapy of AD. In this review, we summarize the role of immunological and structural epidermal barrier dysfunction, immune abnormalities, impairment of lipids, filaggrin mutation and skin microbiome in the etiopathogenesis of AD, as well as the therapeutic options for AD and their effects on these abnormalities in AD skin.

Trends in eczema prevalence in children and adolescents: A Global Asthma Network Phase I Study

Background

Eczema (atopic dermatitis) is a major global public health issue with high prevalence and morbidity. Our goal was to evaluate eczema prevalence over time, using standardized methodology.

Methods

The Global Asthma Network (GAN) Phase I study is an international collaborative study arising from the International Study of Asthma and Allergies in Children (ISAAC). Using surveys, we assessed eczema prevalence, severity, and lifetime prevalence, in global centres participating in GAN Phase I (2015–2020) and one/ both of ISAAC Phase I (1993–1995) and Phase III (2001–2003). We fitted linear mixed models to estimate 10‐yearly prevalence trends, by age group, income, and region.

Results

We analysed GAN Phase I data from 27 centres in 14 countries involving 74,361 adolescents aged 13–14 and 47,907 children aged 6–7 (response rate 90%, 79%). A median of 6% of children and adolescents had symptoms of current eczema, with 1.1% and 0.6% in adolescents and children, respectively, reporting symptoms of severe eczema. Over 27 years, after adjusting for world region and income, we estimated small overall 10‐year increases in current eczema prevalence (adolescents: 0.98%, 95% CI 0.04%–1.92%; children: 1.21%, 95% CI 0.18%–2.24%), and severe eczema (adolescents: 0.26%, 95% CI 0.06%–0.46%; children: 0.23%, 95% CI 0.02%–0.45%) with larger increases in lifetime prevalence (adolescents: 2.71%, 95% CI 1.10%–4.32%; children: 3.91%, 95% CI 2.07%–5.75%). There was substantial heterogeneity in 10‐year change between centres (standard deviations 2.40%, 0.58%, and 3.04%), and strong evidence that some of this heterogeneity was explained by region and income level, with increases in some outcomes in high‐income children and middle‐income adolescents.

Conclusions

There is substantial variation in changes in eczema prevalence over time by income and region. Understanding reasons for increases in some regions and decreases in others will help inform prevention strategies.

The prevalence and associated factors of asthma, allergic rhinitis, and eczema in Turkish children and adolescents

AIM

We aim to determine the prevalence and related risk factors of asthma and allergic diseases in school children and adolescent in Konya, Turkey, and to compare this prevalence with that of 11 years ago.

METHODS

This descriptive correlational study also includes the third phase of the International Study of Asthma and Allergies in Childhood protocol. A total of 2220 students aged between 6 and 18 took part in this study.

RESULTS

In our study, prevalence of wheezing of 21.8%, eczema of 4.3%, and allergic rhinitis of 43.2% were found in students until this age. In the study, student smoking, school location, history of asthma in the family, mold or moisture at home, and mother's smoking now were related factors for wheezing, while eating habits, breastfeeding, and student's gender were determined as related factors for allergic rhinitis symptoms in the past 12 months. In addition, having a pet, eating habits, and school level were determined as related factors for eczema symptoms in the past 12 months (p < 0.05). As a result of comparison of the findings of this study with the results of the study conducted by Güner et al., it was determined that the rates of wheezing and allergic rhinitis had increased, whereas the rate of eczema had decreased (p < 0.05).

CONCLUSION

It was determined that under the effect of urbanization in Konya, the prevalence of asthma and allergic rhinitis in students had increased, while the prevalence of eczema had decreased.

12-month prevalence of atopic dermatitis in resource-rich countries: a systematic review and meta-analysis

There is a lack of robust prevalence estimates of atopic dermatitis (AD) globally and trends over time due to wide variation of populations and age groups studied, different study methodologies and case definitions used. We sought to characterize 12-month AD prevalence across the life span and change over time in resource-rich countries focusing on population-based studies and using a standardized AD case definition. This systematic review was conducted according to PRISMA guidelines. Medline (Ovid), Embase, WOS core collection, Cinahl, and Popline were searched for studies published since inception through August 15, 2016. Studies were synthesized using random effects meta-analysis. Sources of heterogeneity were investigated using subgroup analyses and meta-regression. From 12,530 records identified, 45 studies met the inclusion criteria. Meta-analysis with random effects revealed the 12-month period prevalence of 9.2% (95% confidence interval 8.4–10.1%). The prevalence was significantly higher among 0–5-year-old children (16.2%; 95% confidence interval 14.2–18.7%) than in older age groups. Studies using a random sampling strategy yielded lower prevalence estimates than studies relying on other sampling methods. There was no clear time trend in AD prevalence over the period of 1992–2013.

Asthma, bronchitis respiratory symptoms, allergies and home environment: how are they related?

Introduction

Home environmental conditions can affect the prevalence of childhood asthma and allergies.

Aim

To assess the relationship between the prevalence of childhood asthma, bronchitis, and allergies and the condition of the home environment.

Material and methods

In 2018 and 2019, a cross-sectional study on 2932 children from elementary schools in the Silesian Voivodship (Southern Poland) was conducted. The questionnaire was based on the International Study of Asthma and Allergies in Childhood (ISAAC). In order to determine the association between the home environment (presence of moulds, furry pets) and respiratory symptoms and diseases, a logistic regression analysis was performed by calculating the odds ratio (OR), determining p < 0.05 as the level of significance.

Results

Asthma risk factors were male sex, heating with solid fuel and presence of moulds. The prevalence of respiratory symptoms, bronchitis, and allergic diseases is statistically more common with the presence of moulds in dwellings. A protective effect of the presence of pets on the prevalence of asthma (OR = 0.77; 95% CI: 0.59–0.99), allergy to pet allergens (OR = 0.59; 95% CI: 0.45–0.76), allergy to house dust mite (OR = 0.70; 95% CI: 0.56–0.87) and wheeze in the last 12 months (OR = 0.70; 95% CI: 0.54–0.91) and ever (OR = 0.85; 95% CI: 0.70–1.02) was observed.

Conclusions

The study confirmed the known adverse influence of the presence of moulds and heating with solid fuel on the prevalence of asthma, bronchitis, respiratory symptoms and allergic diseases. The protective influence of pets on the occurrence of the health disorders under study was demonstrated.

Effects of Residential Environment and Lifestyle on Atopic Eczema Among Preschool Children in Shenzhen, China

Eczema, one of the most prevalent inflammatory skin diseases among children, is potentially influenced by genetic, environmental and social factors. However, few studies have investigated the effect of residential environment and lifestyle on childhood eczema. Therefore, this study conducted a cross-sectional study based on 2,781 preschool children in Shenzhen, China, during 2015–2016. Logistic regression models were employed to analyze the associations between residential/household environment, lifestyle, dietary habits and eczema in children. The prevalence of eczema among children in Shenzhen was 24.6%. Significant associations (increased odds >50%, P < 0.05) were found between childhood eczema and the factors of using composite wood floors (adjusted OR = 1.777 for doctor-diagnosed eczema, 1.911 for eczema-like symptoms), living in a villa/townhouse (aOR = 3.102, 2.156), the presence of mold or damp stains in the child's room (aOR = 1.807, 2.279), and rarely cleaning the child's room (aOR = 1.513, 1.540). In addition, watching TV/playing computer games for more than one hour per day was significantly associated with eczema (aOR = 1.172, 1.174). Notably, we found that eating rice/pasta one to three times per week may elevate the risk of eczema-like symptoms (aOR = 1.343), which warrants further investigation. In addition, ambient air pollution, in the covariates, may also affect childhood eczema. Therefore, avoiding these adverse factors and creating a low-risk environment are crucial to prevent childhood eczema.

Antibiotic exposure and adverse long-term health outcomes in children: a systematic review and meta-analysis

BACKGROUND

Antibiotics are among the most commonly used drugs in children. In addition to inducing antibiotic resistance, antibiotic exposure has been associated with long-term adverse health outcomes.

METHODS

A systematic search using PRISMA Guidelines to identify original studies reporting associations between antibiotic exposure and long-term adverse health outcomes in children. Overall pooled estimates of the odds ratios (ORs) were obtained using fixed or random-effects models.

RESULTS

We identified 160 observational studies investigating 21 outcomes in 22,103,129 children. Antibiotic exposure was associated with an increased risk of atopic dermatitis (OR 1.40, 95% confidence interval (CI) 1.30-1.52, p<0.01), allergic symptoms (OR 1.93, 95%CI 1.66-2.26, p<0.01), food allergies (OR 1.35, 95%CI 1.20-1.52, p<0.01), allergic rhinoconjunctivitis (OR 1.66, 95%CI 1.51-1.83, p<0.01), wheezing (OR 1.81, 95%CI 1.65-1.97, p<0.01), asthma (OR 1.96, 95%CI 1.76-2.17, p<0.01), increased weight gain or overweight (OR 1.18, 95%CI 1.11-1.26, p<0.01), obesity (OR 1.21, 95%CI 1.05-1.40, p<0.01), juvenile idiopathic arthritis (OR 1.74, 95%CI 1.21-2.52, p<0.01), psoriasis (OR 1.75, 95%CI 1.44-2.11, p<0.01), autism spectrum disorders (OR 1.19, 95%CI 1.04-1.36, p=0.01) and neurodevelopment disorders (OR 1.29, 95%CI 1.09-1.53, p<0.01). Dose-response effects and stronger effects with broad-spectrum antibiotic were often reported. Antibiotic exposure was not associated with an altered risk of allergic sensitisation, infantile colic, abdominal pain, inflammatory bowel disease, celiac disease, type 1 diabetes, fluorosis, and attention deficit hyperactivity disorder.

CONCLUSION

Although a causal association cannot be determined from these studies, the results support the meticulous application of sound antibiotic stewardship to avoid potential adverse long-term health outcomes.

The global burden of atopic dermatitis: lessons from the Global Burden of Disease Study 1990-2017

BACKGROUND

The Global Burden of Disease (GBD) Study provides an annually updated resource to study disease-related morbidity and mortality worldwide.

OBJECTIVES

Here we present the burden estimates for atopic dermatitis (AD), including data from inception of the GBD project in 1990 until 2017.

METHODS

Data on the burden of AD were obtained from the GBD Study.

RESULTS

Atopic dermatitis (AD) ranks 15th among all nonfatal diseases and has the highest disease burden among skin diseases as measured by disability-adjusted life-years (DALYs). Overall, the global DALY rate for AD in 1990 was 121 [95% uncertainty interval (UI) 65·4-201] and remained similar in 2017 at 123 (95% UI 66·8-205). The three countries with the highest DALY rates of AD were Sweden (327, 95% UI 178-547), the UK (284, 95% UI 155-478) and Iceland (277, 95% UI 149-465), whereas Uzbekistan (85·1, 95% UI 45·2-144), Armenia (85·1, 95% UI 45·8-143) and Tajikistan (85·1, 95% UI 46·1-143) ranked lowest.

CONCLUSIONS

The global prevalence rate of AD has remained stable from 1990 to 2017. However, the distribution of AD by age groups shows a bimodal curve with the highest peak in early childhood, decreasing in prevalence among young adults, and a second peak in middle-aged and older populations. We also found a moderate positive correlation between a country's gross domestic product and disease burden. GBD data confirm the substantial worldwide burden of AD, which has remained stable since 1990 but shows significant geographical variation. Lifestyle factors, partially linked to affluence, are likely important disease drivers. However, the GBD methodology needs to be developed further to incorporate environmental risk factors, such as ultraviolet exposure, to understand better the geographical and age-related variations in disease burden.

Comparison of individual-level and population-level risk factors for rhinoconjunctivitis, asthma, and eczema in the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Three

Background

Symptoms of asthma, allergic rhinoconjunctivitis, and atopic eczema in children cluster at both the individual and population levels.

Objectives

To assess individual-level and school-level risk factors for symptoms of rhinoconjunctivitis and compare them to corresponding associations with symptoms of asthma and eczema in Phase Three of the International Study of Asthma and Allergies in Childhood.

Methods

We studied 116,863 children aged 6–7 years from 2163 schools in 59 centres and 22 countries and 224,436 adolescents aged 13–14 years from 2037 schools in 97 centres in 41 countries. Multilevel logistic regression models were fitted with random intercepts for school, centre, and country, adjusting for sex and maternal education at the child level. Associations between symptoms and a range of lifestyle and environmental risk factors were assessed for both the child's exposure and mean exposure at the school. Models were fitted for rhinoconjunctivitis, asthma, and eczema singly (unimorbidity) and for combinations of these conditions (multimorbidity).

Results

Generally, associations between symptoms and exposures at the school level were similar in direction and magnitude to those at the child level. Associations with multimorbidity were stronger than for unimorbidity, particularly in individuals with symptoms of all three diseases, but risk factor associations found in conventional single disease analyses persisted among children with only one condition, after excluding multimorbid groups.

Comparisons of individuals with only one disease showed that many risk factor associations were consistent across the three conditions. More strongly associated with asthma were low birthweight, cat exposure in infancy, and current maternal smoking. Current paracetamol use was more strongly associated with asthma and rhinoconjunctivitis than eczema. Breastfeeding was more strongly associated with eczema than asthma or rhinoconjunctivitis.

The direction and magnitude of most risk factor associations were similar in affluent and non-affluent countries, although notable exceptions include farm animal contact in infancy and larger sibships, which were associated with increased risk of rhinoconjunctivitis in non-affluent countries but reduced risk in affluent countries. In both age groups, current paracetamol use increased risk of each disease to a greater extent in affluent countries than in non-affluent countries. Effects of paracetamol and antibiotics in infancy were more consistent between richer and poorer settings.

Conclusions

Most of the environmental and lifestyle correlates of rhinoconjunctivitis, asthma and eczema in childhood display similarity across the three conditions, even in less affluent settings where allergic sensitisation is less likely to explain the concordant epidemiological patterns.

Trial registration

Not applicable.

Recent advances in atopic dermatitis

The prevalence and disease burden of atopic dermatitis (AD) is substantial. AD causes significant impairment in quality of life. It is also associated with mental disorders as well as cardiovascular diseases. Many factors including race, environment, skin barrier dysfunction, immune regulatory abnormalities, and microbiome have been reported to affect the pathophysiology of AD. A variety of cell types including Th2, Th17, Th22, and type 2 innate lymphoid cells contribute to AD. Cytokines from these immune cells cause abnormal epidermal differentiation and skin barrier dysfunction. Moreover, microbial dysbiosis and deficiency of antimicrobial peptides result in Staphylococcus aureus infection. Recently, new drugs have been successfully launched to target polarized immune pathways that lead to moderate-to-severe AD.

Pet-Keeping in Relation to Asthma, Rhinitis, and Eczema Symptoms Among Adolescents in Kuwait: A Cross-Sectional Study

Background: Findings on the associations between household pet-keeping and allergic diseases, including asthma, rhinitis, and eczema, have been contradictory, with investigations reporting positive, negative, and null associations. This study sought to estimate the prevalence of pet-keeping among families in Kuwait and to assess the associations between pet-keeping and symptoms of allergic diseases among adolescents. Methods: Schoolchildren aged 11-14 years (n = 3,864) were enrolled in this cross-sectional study. The children's parents completed questionnaires regarding their child's environmental exposures, including pet-keeping in the past 12 months, and clinical history and symptoms of allergic diseases. Associations were assessed using Poisson regression with robust variance estimation, and adjusted prevalence ratios (aPRs) and their 95% confidence intervals (CIs) were estimated. Results: Pet-keeping in the past 12 months was reported by 42.8% of the participating families. Birds, cats, rabbits, fish, and dogs were kept by 28.3, 13.2, 7.8, 3.9, and 3.1% of all households, respectively. Current cat ownership was significantly associated with current wheezing (aPR 1.29, 95% CI 1.05-1.58), current rhinitis symptoms (aPR 1.18, 95% CI 1.02-1.36), and ever doctor-diagnosed eczema (aPR 1.25, 95% CI 1.03-1.50). Current rabbit-keeping was positively associated with multiple symptoms of asthma (e.g., study-defined current asthma: aPR 1.38, 95% CI 1.04-1.82) and eczema (e.g., severe eczema: aPR 1.94, 95% CI 1.02-3.71). Similarly, current bird-keeping was associated with study-defined current rhinitis (aPR 1.19, 95% CI 1.05-1.41) and current itchy rash (aPR 1.27, 95% CI 1.10-1.46). Conclusions: Household pet-keeping is very common and diverse in Kuwait and was found to be positively associated with symptoms of allergic diseases among adolescents. The findings of associations between rabbit-keeping and symptoms of asthma and eczema add to the existing literature and further highlight the importance of considering the pet type when assessing such associations.