Reduced risk of hay fever and asthma among children of farmers

The influence of lifestyle and environmental factors on host resilience through a homeostatic skin microbiota: An EAACI Task Force Report

Human skin is colonized with skin microbiota that includes commensal bacteria, fungi, arthropods, archaea and viruses. The composition of the microbiota varies at different anatomical locations according to changes in body temperature, pH, humidity/hydration or sebum content. A homeostatic skin microbiota is crucial to maintain epithelial barrier functions, to protect from invading pathogens and to interact with the immune system. Therefore, maintaining homeostasis holds promise to be an achievable goal for microbiome-directed treatment strategies as well as a prophylactic strategy to prevent the development of skin diseases, as dysbiosis or disruption of homeostatic skin microbiota is associated with skin inflammation. A healthy skin microbiome is likely modulated by genetic as well as environmental and lifestyle factors. In this review, we aim to provide a complete overview of the lifestyle and environmental factors that can contribute to maintaining the skin microbiome healthy. Awareness of these factors could be the basis for a prophylactic strategy to prevent the development of skin diseases or to be used as a therapeutic approach.

An integrated molecular risk score early in life for subsequent childhood asthma risk

BACKGROUND

Numerous children present with early wheeze symptoms, yet solely a subgroup develops childhood asthma. Early identification of children at risk is key for clinical monitoring, timely patient-tailored treatment, and preventing chronic, severe sequelae. For early prediction of childhood asthma, we aimed to define an integrated risk score combining established risk factors with genome-wide molecular markers at birth, complemented by subsequent clinical symptoms/diagnoses (wheezing, atopic dermatitis, food allergy).

METHODS

Three longitudinal birth cohorts (PAULINA/PAULCHEN, n = 190 + 93 = 283, PASTURE, n = 1133) were used to predict childhood asthma (age 5-11) including epidemiological characteristics and molecular markers: genotype, DNA methylation and mRNA expression (RNASeq/NanoString). Apparent (ap) and optimism-corrected (oc) performance (AUC/R2) was assessed leveraging evidence from independent studies (Naïve-Bayes approach) combined with high-dimensional logistic regression models (LASSO).

RESULTS

Asthma prediction with epidemiological characteristics at birth (maternal asthma, sex, farm environment) yielded an ocAUC = 0.65. Inclusion of molecular markers as predictors resulted in an improvement in apparent prediction performance, however, for optimism-corrected performance only a moderate increase was observed (upto ocAUC = 0.68). The greatest discriminate power was reached by adding the first symptoms/diagnosis (up to ocAUC = 0.76; increase of 0.08, p = .002). Longitudinal analysis of selected mRNA expression in PASTURE (cord blood, 1, 4.5, 6 years) showed that expression at age six had the strongest association with asthma and correlation of genes getting larger over time (r = .59, p < .001, 4.5-6 years).

CONCLUSION

Applying epidemiological predictors alone showed moderate predictive abilities. Molecular markers from birth modestly improved prediction. Allergic symptoms/diagnoses enhanced the power of prediction, which is important for clinical practice and for the design of future studies with molecular markers.

Radiation-Detoxified Form of Endotoxin Effectively Activates Th1 Responses and Attenuates Ragweed-Induced Th2-Type Airway Inflammation in Mice

Urbanization with reduced microbial exposure is associated with an increased burden of asthma and atopic symptoms. Conversely, environmental exposure to endotoxins in childhood can protect against the development of allergies. Our study aimed to investigate whether the renaturation of the indoor environment with aerosolized radiation-detoxified lipopolysaccharide (RD-LPS) has a preventative effect against the development of ragweed-induced Th2-type airway inflammation. To explore this, cages of six-week-old BALB/c mice were treated daily with aerosolized native LPS (N-LPS) or RD-LPS. After a 10-week treatment period, mice were sensitized and challenged with ragweed pollen extract, and inflammatory cell infiltration into the airways was observed. As dendritic cells (DCs) play a crucial role in the polarization of T-cell responses, in our in vitro experiments, the effects of N-LPS and RD-LPS were compared on human monocyte-derived DCs (moDCs). Mice in RD-LPS-rich milieu developed significantly less allergic airway inflammation than mice in N-LPS-rich or common environments. The results of our in vitro experiments demonstrate that RD-LPS-exposed moDCs have a higher Th1-polarizing capacity than moDCs exposed to N-LPS. Consequently, we suppose that the aerosolized, non-toxic RD-LPS applied in early life for the renaturation of urban indoors may be suitable for the prevention of Th2-mediated allergies in childhood.

The case for microbial intervention at weaning

Weaning, the transition from a milk-based diet to solid food, coincides with the most significant shift in gut microbiome composition in the lifetime of most mammals. Notably, this period also marks a "window of opportunity" where key components of the immune system develop, and host-microbe interactions shape long-term immune homeostasis thereby influencing the risk of autoimmune and inflammatory diseases. This review provides a comprehensive analysis of the changes in nutrition, microbiota, and host physiology that occur during weaning. We explore how these weaning-associated processes differ across species, lifestyles, and regions of the intestine. Using prinicples of microbial ecology, we propose that the weaning transition is an optimal period for microbiome-targeted therapeutic interventions. Additionally, we suggest that replicating features of the weaning microbiome in adults could promote the successful engraftment of probiotics. Finally, we highlight key research areas that could deepen our understanding of the complex relationships between diet, commensal microbes, and the host, informing the development of more effective microbial therapies.

Laboratory mice with a wild microbiota generate strong allergic immune responses

Allergic disorders are caused by a combination of hereditary and environmental factors. The hygiene hypothesis postulates that early-life microbial exposures impede the development of subsequent allergic disease. Recently developed "wildling" mice are genetically identical to standard laboratory specific pathogen-free (SPF) mice but are housed under seminatural conditions and have rich microbial exposures from birth. Thus, by comparing conventional SPF mice with wildlings, we can uncouple the impact of lifelong microbial exposures from genetic factors on the allergic immune response. We found that wildlings developed larger populations of antigen-experienced T cells than conventional SPF mice, which included interleukin-10-producing CD4 T cells specific for commensal Lactobacilli strains and allergy-promoting T helper 2 (TH2) cells. In models of airway exposure to house dust mite (HDM), recombinant interleukin-33, or Alternaria alternata, wildlings developed strong allergic inflammation, characterized by eosinophil recruitment, goblet cell metaplasia, and antigen-specific immunoglobulin G1 (IgG1) and IgE responses. Wildlings developed robust de novo TH2 cell responses to incoming allergens, whereas preexisting TH2 cells could also be recruited into the allergic immune response in a cytokine-driven and TCR-independent fashion. Thus, wildling mice, which experience diverse and lifelong microbial exposures, were not protected from developing pathological allergic immune responses. Instead, wildlings mounted robust allergic responses to incoming allergens, shedding new light on the hygiene hypothesis.

Geo-climatic risk factors for chronic rhinosinusitis in southwest Iran

Chronic rhinosinusitis (CRS) is a prevalent and disabling paranasal sinus disease associated with some environmental factors. In this study, we evaluated the effect of geo-climatic factors on CRS in a region of southwest Iran. The study mapped the residency addresses of 232 patients with CRS who lived in Kohgiluyeh and Boyer-Ahmad province and had undergone sinus surgery from 2014 to 2019. The effects of Mean Annual Humidity (MAH), Mean Annual Rainfall (MAR), Mean Annual Temperature (MAT), maximum MAT (maxMAT), minimum MAT (minMAT), Mean Annual Evaporation (MAE), wind, elevation, slope, and land cover were assessed on the occurrence of CRS using Geographical Information System (GIS). Statistical analysis was performed using univariate and multivariate binary logistic regression. Patients came from 55 points including villages, towns, and cities. In univariate analysis, climatic factors including MAT (OR = 0.537), minMAT (OR = 0.764), maxMAT (OR = 0.63), MAR (OR = 0.994), and MAH (OR = 0.626) were significantly related to CRS occurrence. Elevation (OR = 0.999), slope (OR = 0.9), and urban setting (OR = 24.667) were the significant determinants among geographical factors when analyzed independently. The multivariate analysis found maxMAT (OR = 0.5), MAR (OR = 0.994), elevation (OR = 0.998), and urban (OR = 16.8) as significant factors affecting CRS occurrence. The urban setting is the most critical factor affecting CRS disease. Cold and dry areas and low attitude are the other risk factors for CRS in Kohgiluyeh and Boyer-Ahmad province, southwest Iran.

The Role of the Microbiome in the Pathogenesis and Treatment of Asthma

The role of the microbiome in the pathogenesis and treatment of asthma is significant. The purpose of this article is to show the interplay between asthma and the microbiome, and main areas that require further research are also highlighted. The literature search was conducted using the PubMed database. After a screening process of studies published before May 2023, a total of 128 articles were selected in our paper. The pre-treatment bronchial microbiome in asthmatic patients plays a role in their responsiveness to treatment. Gut microbiota and its dysbiosis can contribute to immune system modulation and the development of asthma. The association between the microbiome and asthma is complex. Further research is necessary to clarify which factors might moderate that relationship. An appropriate gut microbiome and its intestinal metabolites are a protective factor for asthma development. Prebiotics and certain dietary strategies may have a prophylactic or therapeutic effect, but more research is needed to establish final conclusions. Although the evidence regarding probiotics is ambiguous, and most meta-analyses do not support the use of probiotic intake to reduce asthma, several of the most recent studies have provided promising effects. Further studies should focus on the investigation of specific strains and the examination of their mechanistic and genetic aspects.

What Have Mechanistic Studies Taught Us About Childhood Asthma?

Childhood asthma is a chronic heterogeneous syndrome consisting of different disease entities or phenotypes. The immunologic and cellular processes that occur during asthma development are still not fully understood but represent distinct endotypes. Mechanistic studies have examined the role of gene expression, protein levels, and cell types in early life development and the manifestation of asthma, many under the influence of environmental stimuli, which can be both protective and risk factors for asthma. Genetic variants can regulate gene expression, controlled partly by different epigenetic mechanisms. In addition, environmental factors, such as living space, nutrition, and smoking, can contribute to these mechanisms. All of these factors produce modifications in gene expression that can alter the development and function of immune and epithelial cells and subsequently different trajectories of childhood asthma. These early changes in a partially immature immune system can have dramatic effects (e.g., causing dysregulation), which in turn contribute to different disease endotypes and may help to explain differential responsiveness to asthma treatment. In this review, we summarize published studies that have aimed to uncover distinct mechanisms in childhood asthma, considering genetics, epigenetics, and environment. Moreover, a discussion of new, powerful tools for single-cell immunologic assays for phenotypic and functional analysis is included, which promise new mechanistic insights into childhood asthma development and therapeutic and preventive strategies.

Allergic rhinitis in India

India is the home of nearly 20% of the global population with 1.35 billion people. Of all non-communicable diseases, allergic diseases such as allergic rhinitis (AR) and asthma appear to have increased in India over the past decades. Approximately 22% of adolescents currently suffer from AR in India. However, owing to the lack of adequate epidemiological studies in India, particularly in rural and suburban areas, this number may misrepresent the true burden of this disease. While the risk factors for AR are mainly environmental exposures or genetic factors, several new environmental, social, and behavioural risk factors such as the presence of dumpsters near residences, movement of vehicles near homes, and exposure to artificial light at night have been found to be associated with AR. However, despite international guidelines, the diagnosis and management of AR in India are often suboptimal, for multiple reasons such as the lack of specialized training in allergy and immunology among Indian clinicians, the lack of diagnostic facilities, and the high cost of medications. This review aims at highlighting the current scenario of AR in India and how it differs from the rest of the world. It also highlights the need for developing a strategic approach to enhance the quality of care for allergic diseases by upgrading education and training for healthcare professionals, creating awareness among clinicians and patients, and involving stakeholders and policymakers in making treatments accessible and affordable to patients.

Natural Green Spaces, Sensitization to Allergens, and the Role of Gut Microbiota during Infancy

The environment plays an instrumental role in the developmental origins of health and disease. Protective features of the environment in the development of asthma and atopy have been insufficiently studied. We used data from the CHILD (Canadian Healthy Infant Longitudinal Development) Cohort Study to examine relationships between living near natural green spaces in early infancy in Edmonton, AB, Canada and the development of atopic sensitization at 1 year and 3 years of age in a cohort of 699 infants, and whether these associations were mediated by infant gut microbiota (measured using 16s V4 amplicon sequencing) at 4 months. The Urban Planning Land Vegetation Index (uPLVI) map of the City of Edmonton was used to assess infants' exposure to natural spaces based on their home postal codes, and atopic sensitization was assessed using skin prink testing (SPTs) for common food and inhalant allergens. Our findings suggest there is a protective effect of natural green space proximity on the development of multiple inhalant atopic sensitizations at 3 years (odds ratio = 0.28 [95% CI 0.09, 0.90]). This relationship was mediated by changes to Actinobacteria diversity in infant fecal samples taken at 4 months. We also found a positive association between nature proximity and sensitization to at least one food or inhaled allergen; this association was not mediated by gut microbiota. Together, these findings underscore the importance of promoting natural urban greenspace preservation to improve child health by reducing atopic disease susceptibility. IMPORTANCE Our findings highlight the importance of preserving natural green space in urban settings to prevent sensitization to environmental allergens and promote early-life gut microbiota pathways to this health benefit. These findings support a mediating role of gut microbiome compositions in health and disease susceptibility. This study used unique, accurate, and comprehensive methodology to classify natural space exposure via a high-resolution topographical map of foliage subtypes within the City of Edmonton limits. These methods are improvements from other methods previously used to classify natural space exposure, such as the normalized density vegetation index from satellite imagery, which is not able to distinguish anthropogenic from green space. The use of these methods and the associations found between natural green space exposure and atopic sensitization outcomes support their use in future studies. Our findings also provide many avenues for future research including longer term follow up of this cohort and investigation of a causal role of reduced Actinobacteria diversity on atopic sensitization development.

Intensive poultry farming: A review of the impact on the environment and human health

Poultry farming is one of the most efficient animal husbandry methods and it provides nutritional security to a significant number of the world population. Using modern intensive farming techniques, global production has reached 133.4 mil. t in 2020, with a steady growth each year. Such intensive growth methods however lead to a significant environmental footprint. Waste materials such as poultry litter and manure can pose a serious threat to environmental and human health, and need to be managed properly. Poultry production and waste by-products are linked to NH₃, N₂O and CH₄ emissions, and have an impact on global greenhouse gas emissions, as well as animal and human health. Litter and manure can contain pesticide residues, microorganisms, pathogens, pharmaceuticals (antibiotics), hormones, metals, macronutrients (at improper ratios) and other pollutants which can lead to air, soil and water contamination as well as formation of antimicrobial/multidrug resistant strains of pathogens. Dust emitted from intensive poultry production operations contains feather and skin fragments, faeces, feed particles, microorganisms and other pollutants, which can adversely impact poultry health as well as the health of farm workers and nearby inhabitants. Fastidious odours are another problem that can have an adverse impact on health and quality of life of workers and surrounding population. This study discusses the current knowledge on the impact of intensive poultry farming on environmental and human health, as well as taking a look at solutions for a sustainable future.

Parent perspectives on the benefits and risks of child-livestock interactions

Growing up on a farm or ranch often involves interactions with livestock that present both potential risks and benefits to children. While these "child-livestock interactions" contribute to the burden of agriculturally related injuries to youth in the United States, they may also result in improved immunological health and other benefits. Agricultural upbringings are also widely perceived to improve physical, cognitive, and skill development of children, contributing to a combination of potential benefits and risks known as the "farm kid paradox." Although previous studies show the health impacts of child-livestock interactions, less is known about the ways in which farm and ranch parents perceive the benefits and risks of these interactions, and how and why they choose to raise children around livestock. Our research addresses this gap by analyzing data from semi-structured interviews with 30 parents of children between the ages of 10-18 who produce beef cattle in Kansas. This research is part of a larger anthropological study of the benefits and risks of child-livestock interactions involving parents on beef and dairy operations in multiple states, along with agricultural safety and health professionals. The results offer insights into the experiences, practices, and perspectives of parents, outlining agricultural ways of life in which safety and relations to risk are shaped by patterns of production, family dynamics, values and habits, and other social and cultural dimensions. These insights deepen our understanding of parents' perceptions of both benefits and risks of agricultural childhoods.

Influence of Farm Environment on Asthma during the Life Course: A Population-Based Birth Cohort Study in Northern Finland

We investigated the influence of a farming environment on asthma at three time points from birth to 46 years using the Northern Finland Birth Cohort 1966 (n = 10,926). The prevalence of asthma was investigated by postal questionnaires at 14, 31 and 46 years of age. Exposure to a farming environment was assessed by a postal questionnaire at birth and at 31 and 46 years of age. Odds ratios (ORs) and their 95% confidence intervals (95% CIs) for the prevalence of asthma were obtained from multinomial logistic regression, stratified by sex. Being born in a farmer family was potentially causally associated with lower risk of asthma in males at 31 years of age (OR 0.56, 95% CI 0.37, 0.85) and in females at 46 years of age (OR 0.64, 95% CI 0.44, 0.95). Working as a farmer was not associated with asthma. Exposure to a farming environment in childhood may have a lifelong impact on developing asthma from birth through young adulthood and until middle age, indicating that 'immune deviation' may persist throughout life.

Nurturing by nutrition: On the future of gut microbiota management strategies for autoimmune disease

The incidence of autoimmune disease continues to rise, which urges for new prevention and treatment modalities. The composition of the gut microbiota is associated with both susceptibility and progression of disease. Nutrition significantly shapes the gut microbial composition, and poses as such a modality for both prevention and treatment/adjuvant therapy. At very young age, nutritional intervention targeting the gut microbiota is still possible within a one-size-fits all regime, accompanied by a relatively high effect size. As ageing results in higher interindividual variation induced by cumulative exposome factors, a more personalized approach is needed, having a higher effect size than that of current nutritional intervention. As such, supplementation of microbial consortia consisting of keystone taxa and microbial guilds that are involved in the pathophysiology seem a promising direction to lower the burden of autoimmune disease.

Prevalence and risk factors of asthma in dairy farmers: Ancillary analysis of AIRBAg

BACKGROUND

Prolonged occupational agricultural exposure is associated with an increase in asthma diagnosis. This study aimed to identify the prevalence and risk factors for asthma in dairy farmers.

METHODS

AIRBAg was a cross-sectional study including 1203 representative dairy farmers. They completed a self-administered questionnaire and underwent a health respiratory check-up. Referral to a pulmonologist was made for any participant with wheezing, dyspnoea, chronic bronchitis, a chronic cough or a FEV₁/FEV₆ ratio<80%. They underwent further examinations such as spirometry with a reversibility test. Controls (non-asthmatic dairy farmers and non-farm employees) were matched to each asthma case for sex and age (±5 years). The odds ratios (OR) between asthma and different risk factors were estimated using conditional multivariate logistic regression models.

RESULTS

Active asthma was diagnosed in 107 (8.9%) farmers. Compared with control dairy farmers, there was a positive association with family history of allergy (OR = 8.68; 95% CI [4.26-17.69]), personal history of eczema (OR = 3.39; 95% CI [1.61-7.13]), hay manipulation (OR = 5.36, 95% CI [1.59-18.01]), and a negative association with farm area (OR = 0.92; 95% CI [0.85-0.99]) and handling treated seeds (OR = 0.47; 95% CI [0.23-0.95]). Compared with control non-farm employees, there was a positive association between asthma and family history of allergy (OR = 95.82, 95% CI [12.55-731.47]).

CONCLUSIONS

The prevalence of active asthma in dairy farmers was somewhat higher than the rate observed in the general population but may be controlled by reducing exposure to airborne organic contaminants through occupational adaptions on farms.

Environmental influences on childhood allergies and asthma - The Farm effect

Asthma and allergies are major health problems and exert an enormous socioeconomic burden. Besides genetic predisposition, environmental factors play a crucial role in the development of these diseases in childhood. Multiple worldwide epidemiological studies have shown that children growing up on farms are immune to allergic diseases and asthma. Farm-related exposures shape children's immune homeostasis, via mediators such as N-glycolylneuraminic acid or arabinogalactan, or by diverse environmental microbes. Moreover, nutritional factors, such as breastfeeding or farm milk and food diversity, inducing short-chain fatty acids-producing bacteria in the intestine, contribute to farm-related effects. All farm-related exposures induce an anti-inflammatory response of the innate immunity and increase the differentiation of regulatory T cells and T helper cell type 1. A better understanding of the components of the farm environment, that are protective to the development of allergy and asthma, and their underlying mechanisms, will help to develop new strategies for the prevention of allergy and asthma.

Do Probiotics in Pregnancy Reduce Allergies and Asthma in Infancy and Childhood? A Systematic Review

The maternal immune system is very important in the development of the foetal immune system. Probiotics have been shown to help regulate immune responses. Therefore, it is possible that the administration of probiotics to pregnant women could influence the development of the foetal immune system, reducing the likelihood of infants and children developing an allergic condition. The aim of this research was to conduct a systematic review to determine whether administering probiotics to pregnant women can reduce the incidence of allergic disease in their children. Medline, CINAHL and Embase databases were searched for randomised controlled trials (RCTs) that compared supplementation of probiotics to pregnant women to a placebo control and recorded the presentation of allergic conditions in their children. Data extracted from the study reports included their characteristics and findings. Study quality and risk of bias were assessed. From a total of 850 articles identified in the search, 6 were eligible for inclusion in this review. Two studies found no effect of maternal probiotics on the outcomes measured, two studies found that the incidence of eczema or atopic dermatitis (AD) was reduced by maternal probiotics, one study found no effect on the overall incidence of atopic sensitisation, but a reduction in a subgroup of children at high hereditary risk of allergic disease, and one study found no effect in an intention to treat analysis, but a reduction in AD in complete case analysis. The results of these studies are inconsistent but demonstrate that probiotics may have the potential to reduce infant allergies when administered prenatally, particularly in children at high risk of allergy development. There is a need for further larger-scale studies to be performed in order to provide a more definitive answer. Such studies should focus on at-risk groups.

Household determinants of biocontaminant exposures in Canadian homes

Exposure to biocontaminants, such as dust mites, animal dander, bacteria, and mold, is associated with a range of health effects. This study identified household characteristics associated with indoor biocontaminant loadings in four Canadian cities. Floor dust was collected in 290 Canadian homes in Edmonton, Halifax, Montreal, and Windsor. The dust samples were analyzed for house dust mite allergens (Der f 1 and Der p 1), cat allergen (Fel d 1), cockroach allergen (Bla g 1), beta-(1,3)-D-glucan, and endotoxin. Household information was obtained through questionnaires and home inspections. We performed univariate and multivariate analyses to identify household determinants of biocontaminant loadings and mold odor presence. We observed large regional variations for all biocontaminants, except for cockroach allergen. The ranges of the contaminants measured in loadings and concentrations were similar to that of previous Canadian studies. Household characteristics including presence of carpeting, low floor cleaning frequency, older home age, presence of pets, and indoor relative humidity above 45% were positively associated with the presence of multiple indoor biocontaminants. High floor cleaning frequency and use of dehumidifiers were negatively associated with the presence of multiple indoor biocontaminants. Mold odor was positively associated with older home age, past water damage, and visible mold growth.

Incidence of Pediatric Eosinophilic Esophagitis and Characterization of the Stricturing Phenotype in Alberta, Canada

Limited work has been done to characterize the stricturing pediatric eosinophilic esophagitis (EoE) phenotype. We aimed to determine, in pediatric EoE: the local incidence, the frequency of esophageal stricturing, and the safety of mechanical dilations.

Methods

We retrospectively identified all new cases of EoE at our center from 2015 to 2018 using esophageal biopsy reports, EoE clinic lists, and a local OR database of esophageal dilatations. Electronic medical records (EMRs) were reviewed to confirm EoE diagnosis. Clinical data were captured from the outpatient EMR and gastroscopy/pathology reports. Scope adverse event data were captured from multiple sources. The 2016 census data were used to calculate incidence rates.

Results

One hundred eighty-five new cases of EoE were diagnosed during the study period. For patients <15 years old living in Edmonton, the incidence over the 4 years was 11.1 cases per 100,000 person years. Eight of 185 (4%) patients had endoscopically confirmed esophageal strictures, 4 of which required mechanical dilation. Eleven of 185 (5.9%) patients had more subtle signs of esophageal narrowing, but no focal strictures. No perforations or episodes of significant bleeding were reported. Pain was reported after 15% of all scopes, including 50% of the 28 scopes with focal strictures. No unexpected admissions or emergency department visits occurred within 72 hours of a gastroscope with esophageal narrowing.

Conclusions

Edmonton zone has one of the highest incidences of pediatric EoE reported. In this cohort, 4% had focal esophageal strictures, and 6% had more subtle narrowing. Mechanical dilation of esophageal strictures was associated with no significant adverse events.

Interrupting the Conversation: Implications for Crosstalk Between Viral and Bacterial Infections in the Asthmatic Airway

Asthma is a heterogeneous, chronic respiratory disease affecting 300 million people and is thought to be driven by different inflammatory endotypes influenced by a myriad of genetic and environmental factors. The complexity of asthma has rendered it challenging to develop preventative and disease modifying therapies and it remains an unmet clinical need. Whilst many factors have been implicated in asthma pathogenesis and exacerbations, evidence indicates a prominent role for respiratory viruses. However, advances in culture-independent detection methods and extensive microbial profiling of the lung, have also demonstrated a role for respiratory bacteria in asthma. In particular, airway colonization by the Proteobacteria species Nontypeable Haemophilus influenzae (NTHi) and Moraxella catarrhalis (Mcat) is associated with increased risk of developing recurrent wheeze and asthma in early life, poor clinical outcomes in established adult asthma and the development of more severe inflammatory phenotypes. Furthermore, emerging evidence indicates that bacterial-viral interactions may influence exacerbation risk and disease severity, highlighting the need to consider the impact chronic airway colonization by respiratory bacteria has on influencing host responses to viral infection. In this review, we first outline the currently understood role of viral and bacterial infections in precipitating asthma exacerbations and discuss the underappreciated potential impact of bacteria-virus crosstalk in modulating host responses. We discuss the mechanisms by which early life infection may predispose to asthma development. Finally, we consider how infection and persistent airway colonization may drive different asthma phenotypes, with a view to identifying pathophysiological mechanisms that may prove tractable to new treatment modalities.

Prevalence and risk factors associated with allergic rhinitis in Mexican school children: Global Asthma Network Phase I

Background

The International Study of Asthma and Allergies in Childhood (ISAAC) showed a wide variability in prevalence and severity of allergic rhinitis (AR) and rhinoconjunctivitis (ARC), in addition to other atopic diseases (Asher et al, 2006).¹ The Global Asthma Network (GAN) has continued to study these conditions.

Objective

To estimate the prevalence of AR and ARC in children and adolescents in Mexico and to assess their association with different risk factors.

Methods

GAN Phase I is a cross-sectional, multicentre survey carried out in 15 centres corresponding to 14 Mexican cities throughout 2016–2019 using the validated Spanish language version of the GAN Phase I questionnaires. The questionnaires were completed by 35 780 parents of 6–7 year old primary school pupils (children) and by 41 399 adolescents, 13–14 years old.

Results

The current and cumulative prevalence of AR was higher in the adolescents (26.2–37.5%, respectively) in comparison to the children (17.9–24.9%, respectively), especially in female participants. This tendency was also observed in the current prevalence of ARC, where 15.1% of female adolescents reported nasal symptoms accompanied with itchy-watery eyes in the past year. The most important risk factors for AR and ARC were the presence of wheezing in the past 12 months, wheezing in the first year of life, the previous diagnosis of asthma and eczema symptoms. Furthermore, allergic symptoms had a negative tendency concerning altitude.

Conclusion

This is the largest AR epidemiological study ever conducted in Mexico. It shows an increase in AR prevalence, as well as significant associations with modifiable risk factors, which could help to establish recommendations to reduce the burden of this condition.

Influence of Childhood Exposure to a Farming Environment on Age at Asthma Diagnosis in a Population-Based Study

Purpose

Asthma is a heterogeneous disease, and factors associated with different asthma phenotypes are poorly understood. Given the higher prevalence of farming exposure and late diagnosis of asthma in more rural Western Finland as compared with the capital of Helsinki, we investigated the relationship between childhood farming environment and age at asthma diagnosis.

Methods

A cross-sectional population-based study was carried out with subjects aged 20–69 years in Western Finland. The response rate was 52.5%. We included 3864 participants, 416 of whom had physician-diagnosed asthma at a known age and with data on the childhood environment. The main finding was confirmed in a similar sample from Helsinki. Participants were classified as follows with respect to asthma diagnosis: early diagnosis (0–11 years), intermediate diagnosis (12–39 years), and late diagnosis (40–69 years).

Results

The prevalence of asthma was similar both without and with childhood exposure to a farming environment (11.7% vs 11.3%). Allergic rhinitis, family history of asthma, ex-smoker, occupational exposure, and BMI ≥ 30 kg/m² were associated with a higher likelihood of asthma. Childhood exposure to a farming environment did not increase the odds of having asthma (aOR, 1.10; 95% CI, 0.87–1.40). It did increase the odds of late diagnosis (aOR, 2.30; 95% CI, 1.12–4.69), but the odds were lower for early (aOR, 0.49; 95% CI, 0.30–0.80) and intermediate diagnosis of asthma (aOR, 0.75; 95% CI, 0.47–1.18).

Conclusion

Odds were lower for early diagnosis of asthma and higher for late diagnosis of asthma in a childhood farming environment. This suggests a new hypothesis concerning the etiology of asthma when it is diagnosed late.

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Protection against allergies: Microbes, immunity, and the farming effect

The prevalence of asthma and other allergic diseases has rapidly increased in "Westernized" countries over recent decades. This rapid increase suggests the involvement of environmental factors, behavioral changes or lifestyle, rather than genetic drift. It has become increasingly clear that the microbiome plays a key role in educating the host immune system and, thus, regulation of disease susceptibility. This review will focus on recent advances uncovering immunological and microbial mechanisms that protect against allergies, in particular, within the context of a farming environment. A whole body of epidemiological data disclosed the nature of the protective exposures in a farm. Current evidence points toward an important role of the host microbiome in setting an immunological equilibrium that determines progression toward, or protection against allergic diseases. Conclusive mechanistic insights on how microbial exposures prevent from developing allergic diseases in humans are still lacking but findings from experimental models reveal plausible immunological mechanisms. Gathering further knowledge on these mechanisms and confirming their relevance in humans is of great importance to develop preventive strategies for children at risk of developing allergies.

The role of the environment in shaping the trends of childhood asthma - An Asian perspective

Asthma has now become one of the most common atopic disorders not only in developed countries but also in many developing countries. The etiology is likely due to a complex interaction between genetic and environmental factors. In many Asian countries, the prevalence of asthma has also been documented by validated instruments to be increasing rapidly over the past two decades. However, studies in rural areas in Asia with a traditional farming environment revealed markedly lower asthma prevalence when compared with residents in nearby cities despite having similar genetic background. Among the environmental factors implicated in the pathogenesis of asthma, air pollution, dietary patterns, viral infections, and early microbial exposure have been studied extensively around the world. Asia provides many opportunities to study these potential factors as there are many ethnic groups living in distinctly different environments. The understanding of the roles of these factors in affecting the early immune system and subsequent development of asthma will enable us to develop potential primary preventive strategies against a disease which affects millions worldwide.

Respiratory Viral and Bacterial Factors That Influence Early Childhood Asthma

Asthma is a chronic respiratory condition characterised by episodes of shortness of breath due to reduced airway flow. The disease is triggered by a hyperreactive immune response to innocuous allergens, leading to hyper inflammation, mucus production, changes in structural cells lining the airways, and airway hyperresponsiveness. Asthma, although present in adults, is considered as a childhood condition, with a total of about 6.2 million children aged 18 and below affected globally. There has been progress in understanding asthma heterogeneity in adults, which has led to better patient stratification and characterisation of multiple asthma endotypes with distinct, but overlapping inflammatory features. The asthma inflammatory profile in children is not well-defined and heterogeneity of the disease is less described. Although many factors such as genetics, food allergies, antibiotic usage, type of birth, and cigarette smoke exposure can influence asthma development particularly in children, respiratory infections are thought to be the major contributing factor in poor lung function and onset of the disease. In this review, we focus on viral and bacterial respiratory infections in the first 10 years of life that could influence development of asthma in children. We also review literature on inflammatory immune heterogeneity in asthmatic children and how this overlaps with early lung development, poor lung function and respiratory infections. Finally, we review animal studies that model early development of asthma and how these studies could inform future therapies and better understanding of this complex disease.

Land Cover of Early-Life Environment Modulates the Risk of Type 1 Diabetes

OBJECTIVE

Environmental microbial exposures have been implicated to protect against immune-mediated diseases such as type 1 diabetes. Our objective was to study the association of land cover around the early-life dwelling with the development of islet autoimmunity and type 1 diabetes to evaluate the role of environmental microbial biodiversity in the pathogenesis.

RESEARCH DESIGN AND METHODS

Association between land cover types and the future risk of type 1 diabetes was studied by analyzing land cover types classified according to Coordination of Information on the Environment (CORINE) 2012 and 2000 data around the dwelling during the first year of life for 10,681 children genotyped for disease-associated HLA-DQ alleles and monitored from birth in the Type 1 Diabetes Prediction and Prevention (DIPP) study. Land cover was compared between children who developed type 1 diabetes (n = 271) or multiple diabetes-associated islet autoantibodies (n = 384) and children without diabetes who are negative for diabetes autoantibodies.

RESULTS

Agricultural land cover around the home was inversely associated with diabetes risk (odds ratio 0.37, 95% CI 0.16-0.87, P = 0.02 within a distance of 1,500 m). The association was observed among children with the high-risk HLA genotype and among those living in the southernmost study region. Snow cover on the ground seemed to block the transfer of the microbial community indoors, leading to reduced bacterial richness and diversity indoors, which might explain the regional difference in the association. In survival models, an agricultural environment was associated with a decreased risk of multiple islet autoantibodies (hazard ratio [HR] 1.60, P = 0.008) and a decreased risk of progression from single to multiple autoantibody positivity (HR 2.07, P = 0.001) compared with an urban environment known to have lower environmental microbial diversity.

CONCLUSIONS

The study suggests that exposure to an agricultural environment (comprising nonirrigated arable land, fruit trees and berry plantations, pastures, natural pastures, land principally occupied by agriculture with significant areas of natural vegetation, and agroforestry areas) early in life is inversely associated with the risk of type 1 diabetes. This association may be mediated by early exposure to environmental microbial diversity.

Indoor bacterial, fungal and viral species and functional genes in urban and rural schools in Shanxi Province, China-association with asthma, rhinitis and rhinoconjunctivitis in high school students

BACKGROUND

Studies in developed countries have reported that the prevalence of asthma and rhinitis is higher in urban areas than in rural areas, and this phenomenon is associated with urbanization and changing indoor microbiome exposure. Developing countries such as China have experienced rapid urbanization in past years, but no study has investigated microbiome exposure and urban-rural health effects in these countries.

METHODS

Nine high schools from urban and rural areas were randomly selected in Shanxi Province, China, and classroom vacuum dust was collected for shotgun metagenomic sequencing. A self-administered questionnaire was collected from 1332 students for personal information and health data. Three-level logistic regression was performed between microbial richness/abundance/functional pathways and the occurrence of asthma and rhinitis symptoms.

RESULTS

Consistent with developed countries, the prevalence of wheeze and rhinitis was higher in urban areas than in rural areas (p < 0.05). Metagenomic profiling revealed 8302 bacterial, 395 archaeal, 744 fungal, 524 protist and 1103 viral species in classroom dust. Actinobacteria (mean relative abundance 49.7%), Gammaproteobacteria (18.4%) and Alphaproteobacteria (10.0%) were the most abundant bacterial classes. The overall microbiome composition was significantly different between urban and rural schools (p = 0.001, Adonis). Species from Betaproteobactera, Gammaproteobacteria and Bacilli were enriched in urban schools, and species from Actinobacteria and Cyanobacteria were enriched in rural schools. Potential pathogens were present in higher abundance in urban schools than in rural schools (p < 0.05). Pseudoalteromonas, Neospora caninum and Microbacterium foliorum were positively associated with the occurrence of wheeze, rhinitis and rhinoconjunctivitis, and Brachybacterium was protectively (negatively) associated with rhinitis (p < 0.01). The abundance of human endocrine and metabolic disease pathways was positively associated with rhinitis (p = 0.008), and butyrate and propionate metabolic genes and pathways were significantly enriched in rural schools (p < 0.005), in line with previous findings that these short-chain fatty acids protect against inflammatory diseases in the human gut.

CONCLUSIONS

We conducted the first indoor microbiome survey in urban/rural environments with shotgun metagenomics, and the results revealed high-resolution microbial taxonomic and functional profiling and potential health effects. Video abstract.

Loss of allergy-protective capacity of raw cow's milk after heat treatment coincides with loss of immunologically active whey proteins

The allergy-protective capacity of raw cow's milk was demonstrated to be abolished after heat treatment. The heat-sensitive whey protein fraction of raw milk is often implied to be the source of this allergy-protective effect, but a direct link between these proteins and the protection against allergic diseases is missing. This study therefore aimed at investigating the mechanistic relation between heat damage to whey proteins and allergy development. Raw cow's milk was heated for 30 min at 50, 60, 65, 70, 75, or 80 °C and the native whey protein profile of these differentially heated milk samples was determined using LC-MS/MS-based proteomics. Changes in the native protein profile were subsequently related to the capacity of these milk samples to prevent the development of ovalbumin-induced food allergy in a murine animal model. A substantial loss of native whey proteins, as well as extensive protein aggregation, was observed from 75 °C. However, whey proteins with immune-related functionalities already started to denature from 65 °C, which coincided with the temperature at which a loss of allergy protection was observed in the murine model. Complement C7, monocyte differentiation antigen CD14, and polymeric immunoglobulin receptor concentrations decreased significantly at this temperature, although several other immunologically active whey proteins also showed a decrease around 65 °C. The current study demonstrates that immunologically active whey proteins that denature around 65 °C are of importance for the allergy-protective capacity of raw cow's milk and thereby provides key knowledge for the development of microbiologically safe alternatives to raw cow's milk.

A review of epigenetic changes in asthma: methylation and acetylation

Several studies show that childhood and adulthood asthma and its symptoms can be modulated through epigenetic modifications. Epigenetic changes are inheritable modifications that can modify the gene expression without changing the DNA sequence. The most common epigenetic alternations consist of DNA methylation and histone modifications. How these changes lead to asthmatic phenotype or promote the asthma features, in particular by immune pathways regulation, is an understudied topic. Since external effects, like exposure to tobacco smoke, air pollution, and drugs, influence both asthma development and the epigenome, elucidating the role of epigenetic changes in asthma is of great importance. This review presents available evidence on the epigenetic process that drives asthma genes and pathways, with a particular focus on DNA methylation, histone methylation, and acetylation. We gathered and assessed studies conducted in this field over the past two decades. Our study examined asthma in different aspects and also shed light on the limitations and the important factors involved in the outcomes of the studies. To date, most of the studies in this area have been carried out on DNA methylation. Therefore, the need for diagnostic and therapeutic applications through this molecular process calls for more research on the histone modifications in this disease.

Raw Milk-Induced Protection against Food Allergic Symptoms in Mice Is Accompanied by Shifts in Microbial Community Structure

The mechanism underlying the allergy-protective effects of raw cow’s milk is still unknown, but the modulation of the gut microbiome may play a role. The effects of consuming raw cow’s milk or processed milk on fecal microbial communities were therefore characterized in an experimental murine model. C3H/HeOuJ mice were treated with raw milk, pasteurized milk, skimmed raw milk, pasteurized milk supplemented with alkaline phosphatase (ALP), or phosphate-buffered saline (PBS) for eight days prior to sensitization and challenge with ovalbumin (OVA). Fecal samples were collected after milk exposure and after OVA sensitization, and microbiomes were characterized using 16S ribosomal RNA gene amplicon sequencing. Treatment with raw milk prior to OVA sensitization increased the relative abundance of putative butyrate-producing bacteria from the taxa Lachnospiraceae UCG-001, Lachnospiraceae UCG-008, and Ruminiclostridium 5 (Clostridial clusters XIVa and IV), while it decreased the relative abundance of Proteobacterial genera such as Parasutterella, a putative pro-inflammatory bacterial genus. This effect was observed after eight days of raw milk exposure and became more pronounced five weeks later, after allergic sensitization in the absence of milk. Similar trends were observed after treatment with skimmed raw milk. Conversely, the feeding of pasteurized milk led to a loss of allergy protection and a putative dysbiotic microbiome. The addition of ALP to pasteurized milk restored the protective effect observed with raw milk and mitigated some of the microbial community alterations associated with milk pasteurization. Raw milk-induced protection against food allergic symptoms in mice is accompanied by an increased relative abundance of putative butyrate-producing Clostridiales and a decreased relative abundance of putative pro-inflammatory Proteobacteria. Given the safety concerns regarding raw milk consumption, this knowledge is key for the development of new, microbiologically safe, preventive strategies to reduce the incidence of allergic diseases.

Umbilical cord blood metabolome differs in relation to delivery mode, birth order and sex, maternal diet and possibly future allergy development in rural children

Allergy is one of the most common diseases among young children yet all factors that affect development of allergy remain unclear. In a small cohort of 65 children living in the same rural area of south-west Sweden, we have previously found that maternal factors, including prenatal diet, affect childhood allergy risk, suggesting that in utero conditions may be important for allergy development. Here, we studied if metabolites in the umbilical cord blood of newborns may be related to development of childhood allergy, accounting for key perinatal factors such as mode of delivery, birth order and sex. Available umbilical cord blood plasma samples from 44 of the participants were analysed using gas chromatography-mass spectrometry metabolomics; allergy was diagnosed by specialised paediatricians at ages 18 months, 3 years and 8 years and included eczema, asthma, food allergy and allergic rhinoconjunctivitis. Nineteen cord blood metabolites were related to future allergy diagnosis though there was no clear pattern of up- or downregulation of metabolic pathways. In contrast, perinatal factors birth order, sex and mode of delivery affected several energy and biosynthetic pathways, including glutamate and aspartic acid—histidine metabolism (p = 0.004) and the tricarboxylic acid cycle (p = 0.006) for birth order; branched chain amino acid metabolism (p = 0.0009) and vitamin B₆ metabolism (p = 0.01) for sex; and glyoxylate and dicarboxylic acid metabolism (p = 0.005) for mode of delivery. Maternal diet was also related to some of the metabolites associated with allergy. In conclusion, the cord blood metabolome includes individual metabolites that reflect lifestyle, microbial and other factors that may be associated with future allergy diagnosis, and also reflects temporally close events/factors. Larger studies are required to confirm these associations, and perinatal factors such as birth order or siblings must be considered in future cord-blood metabolome studies.

Total Synthesis of a Partial Structure from Arabinogalactan and Its Application for Allergy Prevention

Arabinogalactan, a microheterogeneous polysaccharide occurring in plants, is known for its allergy-protective activity, which could potentially be used for preventive allergy treatment. New treatment options are highly desirable, especially in a preventive manner, due to the constant rise of atopic diseases worldwide. The structural origin of the allergy-protective activity of arabinogalactan is, however, still unclear and isolation of the polysaccharide is not feasible for pharmaceutical applications due to a variation of the activity of the natural product and contaminations with endotoxins. Therefore, a pentasaccharide partial structure was selected for total synthesis and subsequently coupled to a carrier protein to form a neoglycoconjugate. The allergy-protective activity of arabinogalactan could be reproduced with the partial structure in subsequent in vivo experiments. This is the first example of a successful simplification of arabinogalactan with a single partial structure while retaining its allergy-preventive potential.

Dyspnea has an association with lifestyle: differences between Swedish and Finnish speaking persons in Western Finland

Background Difference in dyspnea mMRC ≥2 between Finnish speaking and Swedish-speaking populations in Finland has not been previously studied.

Methods In February 2016, a respiratory questionnaire was sent to 8000 randomly selected subjects aged 20–69 years in western Finland with a response rate of 52.3%. The registered native language of each subject determined whether questionnaire in Finnish or Swedish was applied. Multiple logistic regression was performed to calculate Odds Ratios (OR) with 95% CI for the simultaneous effects of independent variables on dyspnea mMRC ≥2.

Results Of all participants, 2780 (71.9%) were Finnish speakers and 1084 (28.1%) were Swedish speakers. Finnish speakers had a higher prevalence of dyspnea mMRC ≥2 (11.1% vs 6.5% p < 0.001) when compared to Swedish speakers. Finnish speakers smoked more often, had higher BMI, spent less time moving during the day, had more often occupational exposure to vapours, gases, dusts or fumes (VGDF), and had lower socioeconomic status based on occupation. Significant risk factors for dyspnea mMRC ≥2 were COPD (OR = 10.94), BMI >35 (OR = 9.74), asthma (OR = 4.78), female gender (OR = 2.38), older age (OR = 2.20), current smoking (OR = 1.59), and occupational exposure to VGDF (OR = 1.47).

Conclusions Swedish speakers had less dyspnea mMRC ≥2 which is explained by a healthier lifestyle. Smoking, obesity, and occupational exposures should be in focus to improve respiratory health.

Patterns of farm exposure are associated with reduced incidence of atopic dermatitis in early life

BACKGROUND

Farm exposures may reduce the risk of atopic dermatitis (AD) in children, but this is controversial and US data are limited.

OBJECTIVE

This study was conducted to identify patterns of farm exposure in Wisconsin family farms that modify AD incidence and prevalence in early childhood.

METHODS

Environmental exposures, health history, and clinical outcomes were prospectively recorded for 111 farm families and 129 non-farm families enrolled in the Wisconsin Infant Study Cohort birth cohort study. Exposures from the prenatal and early postnatal (2-month) visits were evaluated together with parental report of AD diagnosis by a health care provider through age 24 months. Latent class analysis was performed with prenatal and early postnatal farm-exposure variables to assign farm children to 3 classes.

RESULTS

Overall, children of farm families had reduced AD incidence (P = .03). Within farm families, exposures including poultry (3% vs 28%; P = .003), pig (4% vs 25%; P = .04), feed grain (13% vs 34%; P = .02), and number of animal species were inversely associated with AD incidence. Among the latent class groups, children in families with diverse or more intense farm exposures (classes A and B) had reduced AD incidence, whereas low-exposure (class C) infants had AD incidence similar to that in nonfarm children.

CONCLUSIONS

Infants in Wisconsin farm families had reduced AD incidence, and patterns of farm exposures further defined AD risk. These findings suggest that exposure to diverse farm animals, feed, and bedding during the prenatal period and in early infancy reduce the risk of early-onset AD, a phenotype associated with multiple other atopic diseases.

Risk factors associated with rhinitis, allergic conjunctivitis and eczema among schoolchildren in Uganda

Background

The prevalence of allergy-related diseases (ARDs), including rhinitis, allergic conjunctivitis and eczema, is on the increase globally. The causes of this increase are not well established.

Objectives

To investigate the risk factors associated with ARDs among schoolchildren in Uganda.

Methods

We conducted a secondary data analysis of a large asthma case–control study involving 1700 schoolchildren, 5–17 years, in urban Uganda. ARDs were defined according to the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Skin prick testing (SPT) was conducted using standard procedures and allergen-specific IgE (asIgE) using ImmunoCAP^®. We employed inverse probability weighted analysis to generate estimated prevalence data and weighted odds ratios.

Results

The lifetime estimated weighted prevalence of reported rhinitis, allergic conjunctivitis and eczema was 43.3%, 39.5% and 13.5%; weighted prevalence in 12 months was 10.1%, 9.1% and 2.3%, respectively. There was overlap of ARDs, with 66.3% of 1193 schoolchildren who reported having ever an ARDs (including asthma) reporting two or more. Risk factors associated with reported rhinitis in the last 12 months were city residence at birth [adjusted odds ratio (95% confidence interval) 2.66 (1.42–4.99) compared to rural]; father’s [2.62 (1.79–3.83)] and mother’s history of allergic disease [2.12 (1.48–3.02)]; frequent de-worming in the last 12 months [2.01 (1.30–3.11), ≥2 versus none]; current high frequency of ‘trucks passing on the street near home’ [2.59 (1.48–4.52), ‘almost all the time’ versus rarely] and positive SPT [1.54 (1.09–2.18)] but not asIgE [1.38 (0.60–3.15)]. The same pattern of risk factors was observed for allergic conjunctivitis and eczema.

Conclusion

We found extensive multi-morbidity of, and overlap in the risk factors for, rhinitis, conjunctivitis and eczema—similar to asthma risk factors—among schoolchildren in urban Uganda. This suggests a similar underlying cause for all ARDs, associated with exposure to urban lifestyles and environment in Uganda.

Proximity to livestock farms and exposure to livestock-related particulate matter are associated with lower probability of medication dispensing for obstructive airway diseases

OBJECTIVES

The aim of this study is to assess whether medication use for obstructive airway diseases is associated with environmental exposure to livestock farms. Previous studies in the Netherlands at a regional level suggested that asthma and chronic obstructive pulmonary disease (COPD) are less prevalent among persons living near livestock farms.

METHODS

A nationwide population-based cross-sectional study was conducted among 7,735,491 persons, with data on the dispensing of drugs for obstructive airway diseases in the Netherlands in 2016. Exposure was based on distances between home addresses and farms and on modelled atmospheric particulate matter (PM₁₀) concentrations from livestock farms. Data were analysed for different regions by logistic regression analyses and adjusted for several individual-level variables, as well as modelled PM₁₀ concentration of non-farm-related air pollution. Results for individual regions were subsequently pooled in meta-analyses.

RESULTS

The probability of medication for asthma or COPD being dispensed to adults and children was lower with decreasing distance of their homes to livestock farms, particularly cattle and poultry farms. Increased concentrations of PM₁₀ from cattle were associated with less dispensing of medications for asthma or COPD, as well (meta-analysis OR for 10th-90th percentile increase in concentration of PM₁₀ from cattle farms, 95%CI: 0.92, 0.86-0.97 for adults). However, increased concentrations of PM₁₀ from non-farm sources were positively associated (meta-analysis OR for 10th-90th percentile increase in PM₁₀-concentration, 95%CI: 1.29, 1.09-1.52 for adults).

CONCLUSIONS

The results show that the probability of dispensing medication for asthma or COPD is inversely associated with proximity to livestock farms and modelled exposure to livestock-related PM₁₀ in multiple regions within the Netherlands. This finding implies a notable prevented risk: under the assumption of absence of livestock farms in the Netherlands, an estimated 2%-5% more persons (an increase in tens of thousands) in rural areas would receive asthma or COPD medication.

The Impact of Milk and Its Components on Epigenetic Programming of Immune Function in Early Life and Beyond: Implications for Allergy and Asthma

Specific and adequate nutrition during pregnancy and early life is an important factor in avoiding non-communicable diseases such as obesity, type 2 diabetes, cardiovascular disease, cancers, and chronic allergic diseases. Although epidemiologic and experimental studies have shown that nutrition is important at all stages of life, it is especially important in prenatal and the first few years of life. During the last decade, there has been a growing interest in the potential role of epigenetic mechanisms in the increasing health problems associated with allergic disease. Epigenetics involves several mechanisms including DNA methylation, histone modifications, and microRNAs which can modify the expression of genes. In this study, we focus on the effects of maternal nutrition during pregnancy, the effects of the bioactive components in human and bovine milk, and the environmental factors that can affect early life (i.e., farming, milk processing, and bacterial exposure), and which contribute to the epigenetic mechanisms underlying the persistent programming of immune functions and allergic diseases. This knowledge will help to improve approaches to nutrition in early life and help prevent allergies in the future.

Respiratory diseases and allergy in farmers working with livestock: a EAACI position paper

Farmers constitute a large professional group worldwide. In developed countries farms tend to become larger, with a concentration of farm operations. Animal farming has been associated with negative respiratory effects such as work-related asthma and rhinitis. However, being born and raised or working on a farm reduces the risk of atopic asthma and rhinitis later in life. A risk of chronic bronchitis and bronchial obstruction/COPD has been reported in confinement buildings and livestock farmers. This position paper reviews the literature linking exposure information to intensive animal farming and the risk of work-related respiratory diseases and focuses on prevention. Animal farming is associated with exposure to organic dust containing allergens and microbial matter including alive microorganisms and viruses, endotoxins and other factors like irritant gases such as ammonia and disinfectants. These exposures have been identified as specific agents/risk factors of asthma, rhinitis, chronic bronchitis, COPD and reduced FEV₁. Published studies on dust and endotoxin exposure in livestock farmers do not show a downward trend in exposure over the last 30 years, suggesting that the workforce in these industries is still overexposed and at risk of developing respiratory disease. In cases of occupational asthma and rhinitis, avoidance of further exposure to causal agents is recommended, but it may not be obtainable in agriculture, mainly due to socio-economic considerations. Hence, there is an urgent need for focus on farming exposure in order to protect farmers and others at work in these and related industries from developing respiratory diseases and allergy.

A Review of Potential Public Health Impacts Associated With the Global Dairy Sector

Strong demand for dairy products has led to a global increase in dairy production. In many parts of the world, dairy systems are undergoing rapid intensification. While increased production may contribute to food security, higher dairy stocking rates in some regions have resulted in increased pressure on natural resources with the potential to affect public health and wellbeing. The aim of this review was to identify and describe the potential health harms and benefits associated with dairy production and consumption. Electronic databases Medline, Embase, Scopus, Web of Science, PubMed, and Google Scholar were searched for published literature that investigated human health impacts of dairy production and consumption. Occupational hazards, environmental health impacts, ecosystem health impacts, foodborne hazards, and diet-related chronic diseases were identified as potential public health hazards. Some impacts, notably climate change, extend beyond directly exposed populations. Dairy production and consumption are also associated with important health benefits through the provision of nutrients and economic opportunities. As the global dairy sector increases production, exposure to a range of hazards must be weighed with these benefits. The review of impacts presented here can provide an input into decision making about optimal levels of dairy production and consumption, local land use, and identification and management of specific hazards from this sector. Future research should consider multiple exposure routes, socioeconomic implications, and environmental factors, particularly in regions heavily dependent on dairy farming.

Interactions between dietary habits and home environmental exposures on respiratory symptoms in Romanian school children: an analysis of data from the SINPHONIE project

In this study, we investigated the interactions between household pollutants and dietary habits on children's respiratory health. Our cross-sectional study collected self-reported information including health symptoms (allergy-like, asthma-like, and flu-like symptoms), home characteristics, dietary habits, and demographic information from questionnaires administered to parents of 280 school children in Romania. Unconditional logistic regression and stratified analyses were used to assess the interactions between dietary factors and environmental exposures on health symptoms among children, controlling for sociodemographic characteristics and co-exposures. We found that frequency of fruit consumption had significant interaction with residing near heavy traffic on allergy-like symptoms among children (p = 0.036). However, no association was observed by frequency of fruit consumption. Although no significant interaction was observed, we found that students with infrequent fruit consumption and residing near heavy traffic roads had elevated odds of asthma-like (POR 6.37; 95% CI 1.22, 33.29) and flu-like symptoms (POR 3.75; 95% CI 1.12, 11.86) than those who frequently consumed fruits. Likewise, low vegetable consumption was associated with increased asthma-like symptoms (POR 2.93; 95% CI 1.04, 8.24). Increased odds of asthma-like symptoms were observed among school children that resided near heavy traffic roads and frequently consumed milk (POR 2.80; 95% CI 1.24, 6.31) and yoghurt (POR 2.86; 95% CI 1.05, 7.75) compared to those that infrequently consumed dairy. Our findings suggest that frequent fruit and vegetable consumption may mitigate the negative effects of exposure to heavy traffic near dwelling on respiratory symptoms in Romanian children.

Comparative Study of Food Allergies in Children from China, India, and Russia: The EuroPrevall-INCO Surveys

BACKGROUND

A clear understanding of the differences in the epidemiology of food allergy between rural and urban populations may provide insights into the causes of increasing prevalence of food allergy in the developed world.

OBJECTIVE

We used a standardized methodology to determine the prevalence and types of food-specific allergic sensitization and food allergies in schoolchildren from urban and rural regions of China, Russia, and India.

METHODS

The current study is a multicenter epidemiological survey of children recruited from 5 cities in China (Hong Kong and Guangzhou), Russia (Tomsk), and India (Bengaluru and Mysore) and 1 rural county in Southern China (Shaoguan). A total of 35,549 children aged 6 to 11 years from 3 countries participated in this survey. Random samples of children from 3 countries were first screened by the EuroPrevall screening questionnaire. Children with and without a history of adverse reactions to foods were then recruited for the subsequent case-control comparative studies. We determined the prevalence rates of food-specific IgE sensitization and food allergies using the predefined criteria.

RESULTS

The prevalence rates of food-specific IgE sensitization (≥0.7 kU/L) to at least 1 food were 16.6% in Hong Kong, 7.0% in Guangzhou, 16.8% in rural Shaoguan, 8.0% in Tomsk, and 19.1% in India. Using a definition of probable food allergy as reporting allergic symptoms within 2 hours of ingestion of a specific food plus the presence of allergic sensitization to the specific food (positive IgE and/or positive skin prick test result), the prevalence of food allergy was highest in Hong Kong (1.50%), intermediate in Russia (0.87%), and lowest in Guangzhou (0.21%), Shaoguan (0.69%), and India (0.14%). For children recruited from Hong Kong, both sensitization and food allergy were significantly higher in children who were born and raised in Hong Kong when compared with those who were born in mainland China and migrated to Hong Kong, highlighting the importance of early-life exposures in affecting the subsequent development of food sensitization and food allergy.

CONCLUSIONS

There are wide variations in the prevalence of food-specific IgE sensitization and food allergy in the 3 participating countries. Food allergy appears to be less common when compared with developed countries. The variations in the prevalence of food allergen sensitization cannot be explained by the differences in the degree of urbanization. Despite the high prevalence of food-specific IgE sensitization in India and rural China, food allergy is still extremely uncommon. In addition to IgE sensitization, other factors must play important roles resulting in the clinical manifestations of food allergies.

The Beneficial Effect of Farm Milk Consumption on Asthma, Allergies, and Infections: From Meta-Analysis of Evidence to Clinical Trial

The low prevalence of asthma and allergies in farm children has partially been ascribed to the consumption of raw cow's milk. A literature search identified 12 publications on 8 pertinent studies. A meta-analysis corroborated the protective effect of raw milk consumption early in life (<1 to 5 years, according to study) on asthma (odds ratio [OR], 0.58; 95% CI, 0.49-0.69), current wheeze (OR, 0.66; 95% CI, 0.55-0.78), hay fever or allergic rhinitis (OR, 0.68; 95% CI, 0.57-0.82), and atopic sensitization (OR, 0.76; 95% CI, 0.62-0.95). The effect particularly on asthma was observed not only in children raised on farms (OR, 0.62; 95% CI, 0.58-0.82) but also in children living in rural areas but not on a farm (OR, 0.60; 95% CI, 0.48-0.74). This demonstrates that the effect of farm milk consumption is independent of other farm exposures and that children not living on a farm can theoretically profit from this effect. Because of the minimal but real risk of life-threatening infections, however, consumption of raw milk and products thereof is strongly discouraged. Raw farm milk and industrially processed milk differ in many instances including removal of cellular components, manipulation of the fat fraction, and various degrees of heating. Preliminary evidence attributes the effect to heat-labile molecules and components residing in the fat fraction. The Milk Against Respiratory Tract Infections and Asthma (MARTHA) trial is currently testing the protective effect of microbiologically safe, minimally processed cow's milk against standard ultra-heat-treated milk in children from 6 months to 3 years with the primary outcome of an asthma diagnosis until age 5 years. If successful, this approach might provide a simple but effective prevention strategy.

How a farming environment protects from atopy

It is now well established that the exposure to certain environments such as farms has the potential to protect from the development of allergies later in life. This protection is achieved when repeated exposure to the farming environment occurs early in life, but persists when children spend sufficient amount of time in contact with livestock and hay, and drink unpasteurized milk. The capacity of farm dust to protect from allergy development lies, amongst others, in the microbe composition in the farm. These protective microbes release various metabolites and cell wall components that change farmers' home dust composition, when compared to urbanized home dust. Additionally, they can colonize various barrier sites (skin, lung, intestine) in farmers' children, leading to persistent changes in the way their immune system and their barrier cells respond to environmental allergens.

Raw Cow's Milk Reduces Allergic Symptoms in a Murine Model for Food Allergy-A Potential Role For Epigenetic Modifications

Epidemiological studies identified raw cow's milk consumption as an important environmental exposure that prevents allergic diseases. In the present study, we investigated whether raw cow's milk has the capacity to induce tolerance to an unrelated, non-milk, food allergen. Histone acetylation of T cell genes was investigated to assess potential epigenetic regulation. Female C3H/HeOuJ mice were sensitized and challenged to ovalbumin. Prior to sensitization, the mice were treated with raw milk, processed milk, or phosphate-buffered saline for eight days. Allergic symptoms were assessed after challenge and histone modifications in T cell-related genes of splenocyte-derived CD4⁺ T cells and the mesenteric lymph nodes were analyzed after milk exposure and after challenge. Unlike processed milk, raw milk decreased allergic symptoms. After raw milk exposure, histone acetylation of Th1-, Th2-, and regulatory T cell-related genes of splenocyte-derived CD4⁺ T cells was higher than after processed milk exposure. After allergy induction, this general immune stimulation was resolved and histone acetylation of Th2 genes was lower when compared to processed milk. Raw milk reduces allergic symptoms to an unrelated, non-milk, food allergen in a murine model for food allergy. The activation of T cell-related genes could be responsible for the observed tolerance induction, which suggested that epigenetic modifications contribute to the allergy-protective effect of raw milk.

Respiratory health, allergies, and the farm environment: design, methods and enrollment in the observational Wisconsin Infant Study Cohort (WISC): a research proposal

Epidemiologic and cross-sectional studies suggest that early life farming and animal exposures are associated with major health benefits, influencing immune development and modifying the subsequent risk of allergic diseases, including asthma. The Wisconsin Infant Study Cohort (WISC) study was established in central Wisconsin to test the hypothesis that early life animal farm exposures are associated with distinct innate immune cell maturation trajectories, decreased allergen sensitization and reduced respiratory viral illness burden during the first 2 years of life. Beginning in 2013, a total of 240 families have been enrolled, 16,522 biospecimens have been collected, and 4098 questionnaires have been administered and entered into a secure database. Study endpoints include nasal respiratory virus identification and respiratory illness burden score, allergic sensitization, expression of allergic disease, and anti-viral immune response maturation and profiles. The WISC study prospective design, broad biospecimen collections, and unique US rural community will provide insights into the role of environmental exposures on early life immune maturation profiles associated with protection from allergic sensitization and significant respiratory viral disease burden. The WISC study findings will ultimately inform development of new strategies to promote resistance to severe respiratory viral illnesses and design primary prevention approaches for allergic diseases for all infants.

Exposure of Children to Rural Lifestyle Factors Associated With Protection Against Allergies Induces an Anti-Neu5Gc Antibody Response

Rural lifestyle has been shown to be highly protective against the development of allergies. Contact to farm-animals or pets and early-life consumption of milk products turned out to be important. These exposures provide contact to N-glycolylneuraminic acid (Neu5Gc), a sialic acid naturally expressed in mammalians but not in humans or microbes although both are able to incorporate exogenously provided Neu5Gc and induce thereby an anti-Neu5Gc antibody response. Farmers' children had elevated levels of anti-Neu5Gc antibodies associated with increased contact to Neu5Gc. Farm-related exposures that were associated with protection against allergies such as exposure to farm-animals or pets and consumption of milk were also associated with an antibody response to Neu5Gc in children. Exposure to cats was associated with increased anit-Neu5Gc IgG levels at different timepoints assessed between 1 year of age and school-age. Moreover, consumption of non-pasteurized milk in the first year of life was associated with increased anti-Neu5Gc IgG levels. Neu5Gc-providing exposures that were associated with protection against allergies were reflected in an elevated anti-Neu5Gc IgG level in children. Exposure to Neu5Gc was associated with anti-inflammation and protection of asthma development in children and mice without contribution of anti-Neu5Gc antibodies.

Urban/rural residence effect on emergency department visits arising from food-induced anaphylaxis

BACKGROUND

Anaphylaxis is a severe and potentially fatal allergic response. Early-life exposure to rural environments may help protect against allergic reaction. This study assesses urban/rural differences by age and race/ethnicity in emergency department (ED) pediatric visit rates for food-induced anaphylaxis.

METHODS

This observational study examined 2009-2014 inpatient and ED data from New York and Florida, using ICD-9-CM diagnostic code (995.6) to identify food-induced anaphylaxis cases <18 y/o. Primary predictor of interest was urban/rural setting, with race/ethnicity and age also evaluated. Associations between ED visit rates and urban/rural setting were evaluated by multivariable hierarchical negative binomial regression with state and year fixed effects.

RESULTS

ED visit rates (per 100,000) for food-induced anaphylaxis were 12.31 and 4.60 in urban and rural settings, respectively. Rates were highest among Blacks (15.26) younger urban children (17.29) and older rural children (6.99). Compared to rural, urban children had significantly higher anaphalaxis ED visit rates (IRR 2.77).

CONCLUSIONS

Food-induced anaphylaxis ED visit rates were highest among younger urban children and Black children, with a notable contrast in age distribution between urban and rural rates. Higher urban rates may be attributed to Hygiene Hypothesis, though racial, economic and emergency care access disparities may also influence these outcomes.

The Role of the Environmental Risk Factors in the Pathogenesis and Clinical Outcome of Atopic Dermatitis

Atopic dermatitis (AD) prevalence is rising worldwide. Literature data suggest the incidence of AD in developing countries is gradually getting close to that of developed ones, in which AD affects 20% of the paediatric population. Such an increment, associated with significant variations in prevalence among the various countries, underlines the importance of environmental factors in the disease onset. Among these, great importance is given to hygiene, intestinal microbiota, exposure to bacterial endotoxins, outdoor living with contact to animals, atmospheric pollution, weather, and diet. Genetic (alteration of the skin barrier function) as well as immunologic factors concur with the environmental ones. Only the systematical study of all these elements can best elucidate AD epidemiology.