Effect of urbanisation on asthma, allergy and airways inflammation in a developing country setting

A cross-sectional study on the self-management of asthma and asthma control among adult asthmatic patients in the Aseer region, KSA

Proper management of asthma is crucial for maintaining control over the disease and has a significant impact on the patient's overall condition. The purpose of this study was to determine the extent of self-management and the level of Asthma control in the patients from the Aseer region of Saudi Arabia, as well as to investigate determinants of illness control. A study was conducted using quantitative cross-sectional methods. Researchers utilised a web-based, self-administered structured questionnaire to gather data. The questionnaire included three sections: a socio-demographic section, an Asthma Self-Management Questionnaire (ASMQ), and Asthma Control Test (ACT). An analysis using the chi-square test was conducted to determine if there was a notable connection between the socio-demographic characteristics of the participants and the level of asthma control. A total of 305 responses were collected. The average score for the Asthma Self-Management Questionnaire was 5.72, which corresponds to 40.9%. Based on the scores from the Asthma Control Test, it was found that 60 patients (20.0%) had asthma that was not under control, 94 (30.0%) had asthma that was partially controlled, and 151 (50.0%) had asthma that was well controlled. Factors such as gender, non-smoking status, and having asthma for over 10 years (p ˂0.05) were found to be strongly correlated with improved disease control. Significant gaps were found in patients' awareness of the most important and critical aspects concerning the condition, medications, and preventative actions that limit asthma aggravation. To address the current situation, hospitals and clinics must make substantial efforts.

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.

Geographische Unterschiede zwischen städtischem und ländlichem Raum beim Risiko für atopische Dermatitis: Systematischer Review und Meta-Analyse

Die atopische Dermatitis ist die häufigste chronisch‐entzündliche Hauterkrankung im Kindesalter. Einige Studien kamen zu dem Ergebnis, das Risiko für diese Erkrankung sei im städtischen Raum höher als im ländlichen. Wir haben die verfügbaren Studien systematisch untersucht und eine Meta‐Analyse durchgeführt, um Unterschiede im Risiko für atopische Dermatitis zwischen städtischem und ländlichem Raum zu erkennen. Die Suche in den Datenbanken Embase und MEDLINE wurde am 19. April 2021 durchgeführt. Einschlusskriterium war das Stichwort “Beobachtungsstudie”. Wir haben außerdem Subgruppenanalysen bezüglich Patientenalter, Publikationsjahr und Land durchgeführt. Insgesamt wurden bei der Datenbanksuche 2115 Studien aufgefunden, von denen letztlich 43 Studien mit insgesamt 1 728 855 Patienten in die Meta‐Analyse eingeschlossen wurden. Ein Wohnsitz im städtischen Raum war mit einem erhöhten Risiko für atopische Dermatitis assoziiert; die Odds Ratio war 1,56 (95 %‐Konfidenzintervall 1,43–1,71). Dieses signifikant erhöhte Risiko war nur bei Kindern zu beobachten (Odds Ratio 1,55, 95 %‐Konfidenzintervall 1,39–1,73), nicht jedoch bei Erwachsenen. Hier betrug die Odds Ratio 1,29 (95 %‐Konfidenzintervall 0,99–1,67). Das Risiko für atopische Dermatitis ist in den letzten Jahrzehnten angestiegen, wobei das Risiko in Entwicklungsländern mit einer Odds Ratio von 1,95 höher liegt als in Industrieländern (Odds Ratio 1,35). Unsere Studie bestätigt die Assoziation zwischen atopischer Dermatitis und dem Wohnsitz im städtischen gegenüber dem ländlichen Raum.

Geographic differences in atopic dermatitis risk between urban and rural area: A systematic review and meta-analysis

Atopic dermatitis is the most common chronic inflammatory skin disease affecting children. Some studies have reported a higher risk of atopic dermatitis in urban areas than in rural areas. We systematically reviewed and carried out a meta-analysis to investigate the differences in the development of atopic dermatitis between urban and rural areas. The search was performed on April 19, 2021, using Embase and MEDLINE databases. Eligible for inclusion were observational studies. Subgroup analyses were performed for age, publication year, and country. We identified 2,115 studies, and 43 studies with 1,728,855 subjects were finally included. Urban residency was associated with an increased risk of atopic dermatitis, with an odds ratio of 1.56 (95% confidence interval, 1.43-1.71). A significantly increased risk was observed only in children, with an odds ratio of 1.55 (95% confidence interval, 1.39-1.73), but not in adults, with an odds ratio of 1.29 (95% confidence interval, 0.99-1.67). The risk has increased in recent decades, with a higher risk in developing countries (odds ratio, 1.95) compared to developed countries (odds ratio, 1.35). Our study provides evidence of an association between atopic dermatitis and urban compared to rural living.

Understanding and controlling asthma in Latin America: A review of recent research informed by the SCAALA programme

Asthma is an important health concern in Latin America (LA) where it is associated with variable prevalence and disease burden between countries. High prevalence and morbidity have been observed in some regions, particularly marginalized urban populations. Research over the past 10 years from LA has shown that childhood disease is primarily non-atopic. The attenuation of atopy may be explained by enhanced immune regulation induced by intense exposures to environmental factors such as childhood infections and poor environmental conditions of the urban poor. Non-atopic symptoms are associated with environmental and lifestyle factors including poor living conditions, respiratory infections, psychosocial stress, obesity, and a diet of highly processed foods. Ancestry (particularly African) and genetic factors increase asthma risk, and some of these factors may be specific to LA settings. Asthma in LA tends to be poorly controlled and depends on access to health care and medications. There is a need to improve management and access to medication through primary health care. Future research should consider the heterogeneity of asthma to identify relevant endotypes and underlying causes. The outcome of such research will need to focus on implementable strategies relevant to populations living in resource-poor settings where the disease burden is greatest.

EAST in Children with Allergic rhinitis: Experience from Indian Tertiary Centre

Allergic rhinitis (AR) is recognized as a growing global health disease with considerable importance among children and adolescents. This study aims to study the clinical and sensitization profile of children with allergic rhinitis using EAST. All children presenting to pediatric ENT outpatient with a clinical diagnosis of AR were prospectively recruited. Detailed demographic and clinical history including self-reported allergens, predominant symptoms and associated comorbid conditions were obtained. Severity of symptoms was graded on a visual analogue scale. Specific Ig E antibodies to 20 inhalant allergens was measured using EAST (EUROIMMUN, Germany).The pattern of sensitization was analyzed with respect to age, symptoms, associated comorbid conditions and urbanization. We recruited 328 children with a clinical diagnosis of AR (Mean age 10.3 year, IQR 8-13 years) Nasal block was the predominant symptom across all age groups, sneezing became more troublesome during adolescence. In 191 children sera were tested for allergen specific IgE, 119 (62.3%) showed positive sensitization. The most common sensitization noted was for cockroach, followed by dust mite and pollens. Majority had polysensitization (73%). Those who were predominantly sneezers were more likely to be sensitized with indoor allergens (p < 0.05). Among the comorbid conditions, asthma and atopic dermatitis accounted for maximum non ENT physician visits. The pattern of sensitization did not vary with age, urbanization or comorbid condition. This study highlights the clinical and sensitization profile of children with AR in South East India. Various peculiarities of this community has been presented which needs further attention.

Risk Factors of Childhood Asthma Among Patients Attending a Tertiary Care Centre in North-East India

Introduction

Asthma is a chronic lung illness marked by a reversible airway blockage. Both genetic and environmental factors influence higher asthma rates. The present study aims to assess the various socio-demographic and environmental factors influencing the causation of childhood asthma among patients attending the Paediatric Department of Gauhati Medical College and Hospital (GMCH), Assam.

Materials and Methods

A total of 150 clinically diagnosed asthma patients of 3–12 years as cases and patients of the same age group free from respiratory diseases with no history of asthma in a 1:1 ratio as controls were selected. A predesigned and pretested proforma was used to collect data, and written informed consent was obtained from all the legal guardians of the participants. Data were analyzed by chi-square test and binary logistic regression using SPSS V20, considering a p-value <0.05 significant.

Results

Urban and male children were found to be at higher risk of developing asthma. Children belonging to the urban locality (OR= 4.53; 95% CI: 1.57–13.09; p<0.05), damp environment (OR= 5.21; 95% CI: 1.23–22.10; p<0.05), lower socioeconomic status (OR= 3.48; 95% CI: 1.34–9.01; p<0.05), presence of pets (OR= 6.77; 95% CI: 1.76–25.99; p<0.05), family history of atopy/ allergy (OR= 43.29; 95% CI: 5.80–323.15 p<0.05), smoking/passive smoking (OR=23.54; 95% CI: 1.41–394.21 p<0.05) and mixed feeding (OR= 4.47; 95% CI: 1.46–13.63 p<0.05) were the significant risk factors of childhood asthma.

Conclusion

Children are vulnerable to environmental-induced asthma. Awareness and preventive measures are necessary to control and reduce the burden of childhood asthma.

Assessing the prevalence and severity of asthma, rhinitis, and eczema among schoolchildren (6-7 and 13-14 years old) in Khuzestan, Iran: a cross-sectional survey

Background

Asthma and allergic complications are the most common chronic disorders in children and adolescents. This study aimed to determine the prevalence and severity of asthma, allergic rhinitis, eczema among schoolchildren, and some related risk factors.

Methods

The cross-sectional study was performed in 2019 and involved 4000 students aged 6–7 years and 4000 students aged 13–14 years (both girls and boys) from urban schools in Khuzestan Province, southwestern Iran. We used the multi-stage sampling method. Data were collected using the Persian version of the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire.

Results

The prevalence of current wheeze, wheeze ever and asthma ever in the age group of 6–7 years was 3.8, 4.5, and 1.8%, respectively; in the age group of 13–14 years, it was 4.4, 5.9, and 3.4, respectively. In terms of gender, males (4.9, 6.0, and 2.7 percent, respectively) had substantially higher rates of current wheeze, wheeze ever, and asthma ever compared to the girls (2.8, 3.6, and 2.0 percent, respectively) (p < 0.001). The prevalence of rhinitis, Hay fever, and eczema among young people was 5.3%, 3.5%, and 1.0%, respectively. Current wheeze was more common in children with allergic rhinitis in the last 12 months (30.3% vs. 2.7%, p < 0.001), Hay fever (32.8% vs. 0.3%, p < 0.001) and eczema (27.8% vs 3.8%, p < 0.001), compared to children who did not.

Conclusions

The prevalence and severity of asthma symptoms were significantly associated with allergic rhinitis, eczema, and gender.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12887-022-03520-x.

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.

Pediatric asthma in developing countries: challenges and future directions

PURPOSE OF REVIEW

Asthma continues to be a significant health problem worldwide, and epidemiological studies in the last few decades have consistently shown a marked increase in childhood asthma prevalence. The International Study of Asthma and Allergies in Childhood (ISAAC) showed significant geographic variability in prevalence, and larger associations with morbidity and mortality in low-middle income countries (LMICs). The Global Burden of Disease estimated that 420,000 deaths occurred globally from asthma in 2016, and although asthma prevalence is higher in high-income countries, most asthma-related mortality occurs in LMICs. The general health of a population is measured, in part, by the under-5 childhood death rate, and developing countries still account for more than 80 percentage of child deaths in the world, highlighting the need for efforts to reduce disease burden in these regions.

RECENT FINDINGS

The burden of asthma is higher in developing countries and underserved populations. Despite this, LMICs still face many barriers to appropriate allergy and asthma care, resulting in significant morbidity, potentially preventable asthma deaths, and economic consequences. A 2017 survey of 112 countries participating in the Global Asthma Network found that only 26 countries (23%) had a national asthma plan for children, with a lower proportion in LMICs.

SUMMARY

The rising asthma prevalence and high asthma-related death rates in LMICs suggest that global efforts in improving asthma diagnosis and care are not reaching the most vulnerable communities. Lack of appropriate diagnosis, availability of viable treatment options, and access to specialised care still remain a challenge in many parts of the world. Though barriers to achieving better outcomes differ in specific populations, many LMICs share similar barriers relating to accessibility.

Physical Exercise in the Context of Air Pollution: An Emerging Research Topic

Physical exercise (PE) brings physiological benefits to human health; paradoxically, exposure to air pollution (AP) is harmful. Hence, the combined effects of AP and PE are interesting issues worth exploring. The objective of this study is to review literature involved in AP-PE fields to perform a knowledge-map analysis and explore the collaborations, current hotspots, physiological applications, and future perspectives. Herein, cluster, co-citation, and co-occurrence analysis were applied using CiteSpace and VOSviewer software. The results demonstrated that AP-PE domains have been springing up and in rapid growth since the 21st century. Subsequently, active countries and institutions were identified, and the productive institutions were mainly located in USA, China, UK, Spain, and Canada. Developed countries seemed to be the major promoters. Additionally, subject analysis found that environmental science, public health, and sports medicine were the core subjects, and multidimensional communications were forming. Thereafter, a holistic presentation of reference co-citation clusters was conducted to discover the research topics and trace the development focuses. Youth, elite athletes, and rural population were regarded as the noteworthy subjects. Commuter exposure and moderate aerobic exercise represented the common research context and exercise strategy, respectively. Simultaneously, the research hotspots and application fields were elaborated by keyword co-occurrence distribution. It was noted that physiological adaptations including respiratory, cardiovascular, metabolic, and mental health were the major themes; oxidative stress and inflammatory response were the mostly referred mechanisms. Finally, several challenges were proposed, which are beneficial to promote the development of the research field. Molecular mechanisms and specific pathways are still unknown and the equilibrium points and dose-effect relationships remain to be further explored. We are highly confident that this study provides a unique perspective to systematically and comprehensively review the pieces of AP-PE research and its related physiological mechanisms for future investigations.

Effects of Urban Landscape and Sociodemographic Characteristics on Heat-Related Health Using Emergency Medical Service Incidents

It is well known that extremely hot weather causes heat-related health issues. Health problems, especially in urban areas, are becoming increasingly important due to urban heat island effect. Understanding the impact of neighborhood characteristics is important for research into the relationship between thermal environment and human health. The objectives of this study were to explore the urban landscape and sociodemographic characteristics affecting heat-related health and identify spatial inequalities for vulnerable groups. A total of 27,807 heat-related EMS incidents were used at the census block group level (N = 285). We used land cover database and Landsat satellite images for urban landscape variables and used 2019 U.S. Census data for sociodemographic variables. Negative binomial regression was used to identify the neighborhood variables associated with the heat-related EMS incidents in each block group. Heat-related health has been alleviated in block groups with high green areas. However, the negative effects of thermal environments on human health were higher in areas with a high percentage of impervious surface, over 65 years, non-white people, no high school diploma, or unemployment. The results indicate that heat-related health problems can be addressed through prevention strategies for block group variables. Local intervention efforts to solve health issues should be targeted at more vulnerable areas and groups.

Atopic Dermatitis: Conventional and Integrative Medicine

Although Western medicine and ideas about atopic dermatitis (AD) have become popular in many Asian countries, local beliefs about the disease and its treatment often prevail. The multi- racial background of these countries as well as the influence of the diverse religions (such as Taoism and Ramadan) in these regions often lead to diverse belief systems about the causes of AD (such as the Chi concept, also known as the balance of yin and yang) and the types of treatment (e.g. herbal remedies, topical versus concoctions, and decoctions). In addition, many of the cultural practices are preserved among the Southeast Asian minorities residing in the United Kingdom and North America. Eastern treatments typically take a holistic approach to AD and emphasize the psychosomatic component of the disorder. This overview provides a summary of the difference between conventional, complementary, alternative, and integrative medicine in terms of epidemiology, aetiology, therapy, and prognosis in children with AD. There are a number of similarities in genetic and environmental factors in epidemiology and aetiology; however, differences exist in terms of the concept of management. Complementary and alternative medicine, traditional Chinese medicine, and integrative medicine usage are not only prevalent among the Asian population but are also becoming more popular and accepted in Western societies.

Determinants of asthma in Ethiopia: age and sex matched case control study with special reference to household fuel exposure and housing characteristics

BACKGROUND

Asthma is a chronic inflammatory disorder characterized by airway obstruction and hyper-responsiveness. Studies suggest that household fuel exposure and housing characteristics are associated with air way related allergy. But there remains to be a considerable uncertainty about whether that reflects an association with asthma. This study endeavored to bridge the gap by identifying factors associated with asthma, with special reference to household fuel exposure and housing characteristics in selected public hospitals in Addis Ababa, Ethiopia.

METHODS

We conducted a hospital-based matched case-control study. A total of 483 study participants were selected from two Ethiopian referral hospitals using a sequential sampling technique, with 161 cases and 322 controls. Standard questionnaire from the European Community Respiratory Health Survey II (ECRHS II) and the American Thoracic Society Division of Lung Disease (ATS-DLD-78) were used to collect household related data. Conditional logistic regression model was applied to identify the determinants of asthma. Both crude and adjusted odds ratios with 95% confidence interval (CI) were used to identify predictors of asthma.

RESULTS

The response rate for both cases and controls was 99.17%. The odds of developing asthma was about four times higher among those who used agricultural residues for cooking (AOR: 3.81, 95% CI: 1.05, 13.79)., about five times higher among those who used wood for cooking (AOR: 4.95, 95% CI: 2.1, 11.69), nearly five times higher among those who had family history of asthma (AOR: 4.72, 95% CI: 1.54, 14.45), just over six times higher among those who smoke tobacco (AOR: 6.16, 95% CI: 1.31, 29.09) and over ten times higher among those who do not practice door opening, while cooking (AOR: 10.25, 95% CI: 3.97, 26.49).

CONCLUSION

Family history of asthma, tobacco smoking, use of solid fuels including, woods and agricultural residues were associated with development of asthma. To reduce the risk of asthma, people should practice door opening, while cooking, and must avoid using wood and agricultural residues for cooking and should also refrain from tobacco smoking.

Understanding socio-economic inequalities in the prevalence of asthma in India: an evidence from national sample survey 2017-18

Background

Today, over 300 million people reside with asthma worldwide and India alone is home for 6% of children and 2% of adults suffering from this chronic disease. A common notion of disparity persists in terms of health outcomes across the poor and better-off section of the society. Thus, there is a need to explore socio-economic inequality in the contribution of various factors associated with asthma prevalence in India.

Methods

Data for the study were carved out from the 75th round of National Sample Survey (NSS), collected by the National Sample Survey Organization (NSSO) during 2017–18. The sample size for this study was 555,289 individuals, for which data was used for the analysis. Descriptive statistics were used to show the distribution of the study population. Further, bivariate and multivariate analysis was performed to identify the factors associated with Asthma prevalence. The concentration index was used to measure the inequality. Further, we used decomposition analysis to find the contribution of factors responsible for socio-economic status-related inequality in asthma prevalence.

Results

The prevalence of asthma was 2 per 1000 in the whole population; however, the prevalence differs by age groups in a significant manner. Age, sex, educational status, place of residence, cooking fuel, source of drinking water, household size and garbage disposal facility were significantly associated with asthma prevalence in India. It was found that asthma was more concentrated among individuals from higher socioeconomic status (concentration index: 0.15; p < 0.05). While exploring socio-economic inequality for asthma, richest wealth status (53.9%) was the most significant contributor in explaining the majority of the inequality followed by the urban place of residence (37.9%) and individual from age group 45–65 years (33.3%). Additionally, individual aged 65 years and above (27.9%) and household size less than four members (14.7%) contributed in explaining socio-economic inequality for asthma.

Conclusion

Due to the heterogeneous nature of asthma, associations between different socio-economic indicators and asthma can be complex and may point in different directions. Hence, considering the concentration of asthma prevalence in vulnerable populations and its long-term effect on general health, a comprehensive programme to tackle chronic respiratory diseases and asthma, in particular, is urgently needed.

Effects of air pollution on health: A mapping review of systematic reviews and meta-analyses

BACKGROUND

There has been a notable increase in knowledge production on air pollution and human health.

OBJECTIVE

To analyze the state of the art on the effects of air pollution on human health through a mapping review of existing systematic reviews and meta-analyses (SRs and MAs).

METHODS

The systematic mapping review was based on the recommendations for this type of scientific approach in environmental sciences. The search was performed using PubMed, Web of Science, Scopus, Cinahl, and Cochrane Library databases, from their inception through June 2020.

RESULTS

Among 3401 studies screened, 240 SRs and MAs satisfied the inclusion criteria. Five research questions were answered. There has been an overall progressive increase in publications since 2014. The majority of the SRs and MAs were carried out by researchers from institutions in China, the US, the UK, and Italy. Most studies performed a meta-analysis (161). In general, the reviews support the association of air pollution and health outcomes, and analyzed the effects of outdoor air pollution. The most commonly investigated health outcome type was the respiratory (mainly asthma and COPD), followed by cardiovascular outcomes (mainly stroke). Particulate matter (with a diameter of 2.5 μm (PM_2.5) and 10 μm (PM₁₀) or less) and nitrogen dioxide (NO₂) were the most widely investigated pollutants in the reviews. The general population was the most common sample in the reviews, followed by children, and adults. The majority of the reviews investigated health outcomes of respiratory diseases in children, as well as cardiovascular diseases in all ages. Combining health outcomes and air pollutants, PM_2.5 was included in a higher number of reviews in eight health outcomes, mainly cardiovascular diseases.

DISCUSSION

The majority of SRs and MAs showed that air pollution has harmful effects on health, with a focus on respiratory and cardiovascular outcomes. Future studies should extend the analysis to psychological and social aspects influenced by air pollution.

The effects of indoor and outdoor air pollution on the prevalence of adults' respiratory diseases in four Chinese cities: a comparison between 2017-2018 and 1993-1996

Background

Over the past decades, both ambient and household air pollution have changed in several aspects, including the emission sources and the concentrations of pollutants, in many Chinese cities. It is unknown whether these changes are associated with changes in health conditions, especially given changes in other factors due to rapid economic growth.

Methods

Two cross-sectional surveys were conducted in two periods spanning more than twenty years (1993–1996 vs. 2017–2018) in four Chinese cities of Chongqing, Wuhan, Lanzhou, and Guangzhou. Data were collected regarding adults’ respiratory disease, smoking status, education, occupation, and household characteristics. Ambient air pollution data were obtained for each study. We first used logistic regression models to construct the district-specific adjusted disease prevalences. In the second stage, first-difference regression models were employed to examine whether the change in respiratory diseases prevalences was associated with the change in outdoor air pollution and indoor air pollution surrogates.

Results

A total of 7,557 and 9,974 households were participating in Period 1 (1993–1996) and Period 2 (2017–2018), respectively. Compared to Period 1, we found substantial reductions in the ambient air pollution concentrations, and a suggestive improvement in cooking-related indoor air pollution in Period 2. We observed decreases in the district-specific covariate-adjusted prevalences of both asthma and chronic bronchitis among participants, with an average reduction of 3.6% (range: 0.0% to 24.3%). From Period 1 to Period 2, one percent decrease in the proportion of cooking with coal was associated with a 19.0% (95% CI, 0.96–37.04%) decrease in the prevalence of males’ chronic bronchitis and a 1.86% (0.69–3.04%) increase in the prevalence of females’ asthma. Little evidence was observed regarding the potential health benefits associated with the decreases in ambient air pollution levels.

Conclusions

The substantial reduction in household use of coal for cooking might be an important contributor to the decrease in adults’ respiratory disease prevalence from 1993–1996 to 2017–2019 in four Chinese cities. Changes in this indoor air pollution source, along with other risk factors for respiratory diseases, may have masked respiratory health benefits associated with reductions in outdoor air pollution levels.

Allergic rhinitis aggravated by air pollutants in Latin America: A systematic review

The aim of this systematic review (SR) was to evaluate the most frequent pollutants and their effect on allergic rhinitis in Latin American countries. Observational studies up to December 2020 and comparing different indoor and outdoor pollutants that had allergic rhinitis (AR) as an outcome were included in the systematic review. Random-effect meta-analyses were conducted for the presence of allergic rhinitis. Estimates were presented as pooled odds ratios (ORs) and their respective 95% confidence intervals (CIs). Twenty-two publications comprised this review according to the inclusion and exclusion criteria and 12 had data that could be analyzed statistically. The most frequent pollutant was PM10, followed by NO2 /O3 and PM2.5 in studies conducted in Argentina, Brazil, Bolivia, Chile, Colombia, Costa Rica, and Peru. The OR of an exposed subject experiencing allergic rhinitis was 1.43 (95% CI 1.026; 1.980). The OR of children and adolescents experiencing of allergic rhinitis was 1.359 (95% CI 1.051; 1.759). Asymmetry and great variability in the effect estimated from the selected studies were observed. The publication bias was quantified by Kendall's correlation and Egger's test resulted in 0.152 (p-value = 0.493). Egger's test provided an intercept equal to 2.511 and a p-value = 0.398. The I2 statistic was 89.3% and reinforces the hypothesis of heterogeneity. This first systematic review conducted in Latin America confirmed the chance of a person exposed to pollutants and experiencing allergic rhinitis is 43% greater than that of a non-exposed person, reinforcing the importance of policies to reduce pollutant exposure and the use of protection systems for workforces exposed to occupational pollutants in work environments.

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.

Risk Factors for Physical Inactivity Among Children With and Without Asthma Living in Peri-Urban Communities of Lima, Peru

BACKGROUND

The authors sought to examine physical activity patterns among children with and without asthma in 2 peri-urban communities in Lima, Peru, to identify socioeconomic and demographic risk factors for physical inactivity and examine the relationship between asthma and physical activity.

METHODS

The authors measured mean steps per day in 114 children (49 with asthma and 65 without) using pedometers worn over a 1-week period. They also used the 3-day physical activity recall to determine the most common activities carried out by children.

RESULTS

The authors found that 84.2% of the children did not meet the daily international physical activity recommendations. Girls took significantly fewer mean steps per day as compared with boys (2258 fewer steps, 95% confidence interval, 1042-3474), but no other factors, including asthma status, showed significant differences in the mean daily steps. Mean daily steps were positively associated with higher socioeconomic status among girls, and current asthma had a larger inverse effect on daily steps in boys when compared with girls.

CONCLUSION

Physical activity levels were below recommended guidelines in all children. There is a need for policy and neighborhood-level interventions to address low physical activity levels among Peruvian youth. Special focus should be given to increasing the physical activity levels in girls.

Time-series analysis of ambient PM2.5 and cardiorespiratory emergency room visits in Lima, Peru during 2010-2016

INTRODUCTION

There have been no time-series studies of air pollution in Peru. Here we evaluate the effect of ambient PM_2.5 on emergency room (ER) visits in Lima.

METHODS

We estimated daily PM_2.5 levels at a 1 km² resolution during 2010-2016 using ground measurements, satellite data, and chemical transport model simulations. Population-weighted average daily PM_2.5 levels were calculated for each district in Lima (n = 40), and assigned to patients based on residence. ER visits for respiratory and circulatory diseases were gathered from nine large public hospitals. Poisson regression was used to estimate the rate ratio for daily ER visits with change in daily PM_2.5, controlling for meteorology, time trends, and district.

RESULTS

For each interquartile range (IQR) increase in PM_2.5, respiratory disease ER visits increased 4% (95% CI: 0-5%), stroke visits 10% (3-18%), and ischemic heart disease visits (adults, 18-64 years) 11% (-1, 24%). Districts with higher poverty showed significantly stronger associations of PM_2.5 and respiratory disease ER visits than districts with lower poverty. Effects were diminished 24-42% using Lima-wide instead of district-specific PM_2.5 levels.

CONCLUSIONS

Short-term exposure to ambient PM_2.5 is associated with increases in ER visits in Lima for respiratory diseases and stroke, and among middle-aged adults, ischemic heart disease.

Developmental Origins of Health and Disease: Impact of environmental dust exposure in modulating microbiome and its association with non-communicable diseases

Non-communicable diseases (NCDs) including obesity, diabetes, and allergy are chronic, multi-factorial conditions that are affected by both genetic and environmental factors. Over the last decade, the microbiome has emerged as a possible contributor to the pathogenesis of NCDs. Microbiome profiles were altered in patients with NCDs, and shift in microbial communities was associated with improvement in these health conditions. Since the genetic component of these diseases cannot be altered, the ability to manipulate the microbiome holds great promise for design of novel therapies in the prevention and treatment of NCDs. Together, the Developmental Origins of Health and Disease concept and the microbial hypothesis propose that early life exposure to environmental stimuli will alter the development and composition of the human microbiome, resulting in health consequences. Recent studies indicated that the environment we are exposed to in early life is instrumental in shaping robust immune development, possibly through modulation of the human microbiome (skin, airway, and gut). Despite much research into human microbiome, the origin of their constituent microbiota remains unclear. Dust (also known as particulate matter) is a key determinant of poor air quality in the modern urban environment. It is ubiquitous and serves as a major source and reservoir of microbial communities that modulates the human microbiome, contributing to health and disease. There are evidence that reported significant associations between environmental dust and NCDs. In this review, we will focus on the impact of dust exposure in shaping the human microbiome and its possible contribution to the development of NCDs.

Indoor air pollution concentrations and cardiometabolic health across four diverse settings in Peru: a cross-sectional study

BACKGROUND

Indoor air pollution is an important risk factor for health in low- and middle-income countries.

METHODS

We measured indoor fine particulate matter (PM2.5) and carbon monoxide (CO) concentrations in 617 houses across four settings with varying urbanisation, altitude, and biomass cookstove use in Peru, between 2010 and 2016. We assessed the associations between indoor pollutant concentrations and blood pressure (BP), exhaled carbon monoxide (eCO), C-reactive protein (CRP), and haemoglobin A1c (HbA1c) using multivariable linear regression among all participants and stratifying by use of biomass cookstoves.

RESULTS

We found high concentrations of indoor PM2.5 across all four settings (geometric mean ± geometric standard deviation of PM2.5 daily average in μg/m3): Lima 41.1 ± 1.3, Tumbes 35.8 ± 1.4, urban Puno 14.1 ± 1.7, and rural Puno 58.8 ± 3.1. High indoor CO concentrations were common in rural households (geometric mean ± geometric standard deviation of CO daily average in ppm): rural Puno 4.9 ± 4.3. Higher indoor PM2.5 was associated with having a higher systolic BP (1.51 mmHg per interquartile range (IQR) increase, 95% CI 0.16 to 2.86), a higher diastolic BP (1.39 mmHg higher DBP per IQR increase, 95% CI 0.52 to 2.25), and a higher eCO (2.05 ppm higher per IQR increase, 95% CI 0.52 to 3.57). When stratifying by biomass cookstove use, our results were consistent with effect measure modification in the association between PM2.5 and eCO: among biomass users eCO was 0.20 ppm higher per IQR increase in PM2.5 (95% CI - 2.05 to 2.46), and among non-biomass users eCO was 5.00 ppm higher per IQR increase in PM2.5 (95% CI 1.58 to 8.41). We did not find associations between indoor air concentrations and CRP or HbA1c outcomes.

CONCLUSIONS

Excessive indoor concentrations of PM2.5 are widespread in homes across varying levels of urbanisation, altitude, and biomass cookstove use in Peru and are associated with worse BP and higher eCO.

Noise exposure and childhood asthma up to adolescence

OBJECTIVE

Increasing evidence indicates aggravation of immune-mediated diseases due to physiological and psychological stress. Noise is a stressor, however, little is known about its effects on children's respiratory health. This study investigates the association between pre- or postnatal road traffic or occupational noise exposure and asthma as well as related symptoms from infancy to adolescence.

METHODS

The study was conducted in the Swedish birth cohort BAMSE, including over 4000 participants followed with repeated questionnaires and clinical tests until 16 years of age. Pre- and postnatal residential road traffic noise was assessed by estimating time-weighted average noise levels at the most exposed façade. Maternal occupational noise exposure during pregnancy was evaluated using a job-exposure-matrix. The associations between noise exposure and asthma-related outcomes were explored using logistic regression and generalised estimating equations.

RESULTS

We observed non-significant associations for asthma ever up to 16 years with residential road traffic noise exposure in infancy ≥55 dB_Lden (adjusted OR = 1.22; 95% CI 0.90-1.65), as well as prenatal occupational noise exposure ≥80 dB_LAeq,8h (1.18, 0.85-1.62). In longitudinal analyses, however, no clear associations between pre- or postnatal exposure to residential road traffic noise, or average exposure to noise since birth, were detected in relation to asthma or wheeze until 16 years.

CONCLUSION

We did not find a clear overall association between exposure to noise during different time periods and asthma or wheeze up to adolescence.

Implementation of an intervention to improve the adoption of asthma self-management practices in Peru: Asthma Implementation Research (AIRE) randomized trial study protocol

Introduction

Asthma is the most common chronic disease among children worldwide, with 80% of asthma-related deaths occurring in low- and middle-income countries (LMICs). While evidence-based guidelines exist for asthma treatment and management, adoption of guideline-based practices is low in high-income country and LMIC settings alike. While asthma prevalence among children and adolescents in Lima, Peru is in the range of 13%–19.6%, our data suggest that < 5% of children in low-resource communities are currently taking guideline-based therapies. There is an urgent need for effective, locally tailored solutions to address the asthma treatment gap in low-income communities in Peru.

Methods

This study aims to develop and test a locally adapted intervention package to improve adoption of self-management practices and utilization of preventive health services for asthma among children in Lima Norte. The intervention package was designed using a systematic, theory-based framework (Capability, Opportunity, Motivation – Behavior Framework) and is rooted in a multi-phased formative research approach. The main study design is an individually randomized implementation-effectiveness hybrid trial enrolling 110 children aged 5–17 years with asthma and their caregivers. Families allocated to the treatment group receive the supported self-management intervention package, while families allocated to the control group receive the standard of care plus asthma education. We will follow participants monthly for six months and evaluate asthma control (Asthma Control Test), healthcare utilization, and medication adherence (Adherence to Refills and Medications Scale). Disease-specific quality of life for children (Pediatric Asthma Quality of Life Questionnaire) and caregivers (Pediatric Asthma Caregiver’s Quality of Life Questionnaire) will be evaluated at baseline, 3 months, and 6 months. We will also evaluate acceptability, feasibility, and fidelity of the intervention using mixed methods approaches.

Discussion

The long-term goal of this study is to disseminate locally appropriate asthma management strategies in LMIC settings. This study will contribute to the body of knowledge surrounding approaches for developing and evaluating intervention strategies for asthma using systematic, theory-based approaches grounded in local context. Such strategies have the potential to inform the development and adaptation of appropriate and scalable solutions for asthma management in LMIC settings.

Trial registration

ClinicalTrials.gov, NCT03986177. Registered on 14 June 2019.

Exposure to Traffic-Related Particulate Matter 2.5 Triggers Th2-Dominant Ocular Immune Response in a Murine Model

Ambient particulate matter (PM), a major component of air pollution, aggravates ocular discomfort and inflammation, similarly to dry eye disease (DED) or allergies. However, the mechanism(s) by which PM induces the ocular inflammatory response is unknown. This study investigated the immunological response of traffic-related fine particulate matter (PM_2.5) on the ocular surface in a murine model. C57BL/6 mice were exposed by topical application to PM_2.5 or vehicle for 14 days to induce experimental environmental ocular disease. Corneal fluorescein staining and the number of ocular inflammatory cells were assessed in both groups. The expression of IL-1β, IL-6, tumor necrosis factor (TNF)-α, and mucin 5AC (MUC5AC) in the ocular surface were evaluated by real-time PCR. An immunohistochemical assay evaluated apoptosis and goblet cell density. ELISA was used to determine the levels of serum IgE and cytokines of Type 1 helper (Th1) and Type 2 helper (Th2) cells after in vitro stimulation of T cells in the draining lymph nodes (LNs). Exposure to traffic-related PM_2.5 significantly increased corneal fluorescein staining and cellular toxicity in the corneal epithelium compared with the vehicle control. A significant increase in the number of CD11b+ cells on the central cornea and mast cells in the conjunctiva was observed in the PM_2.5 group. Exposure to PM_2.5 was associated with a significant increase in the corneal or conjunctival expression of IL-1β, IL-6, TNF, and MUC5AC compared to the vehicle, and increased maturation of dendric cells (DCs) (MHC-II^highCD11c⁺) in draining LNs. In addition, PM_2.5 exposure increased the level of serum IgE and Th2 cytokine production in draining LNs on day 14. In conclusion, exposure to traffic-related PM_2.5 caused ocular surface damage and inflammation, which induced DC maturation and the Th2-cell-dominant allergic immune response in draining LNs.

Ambient Air Pollution and Variation in Multiple Domains of Asthma Morbidity among Peruvian Children

RATIONALE

A large portion of asthma morbidity occurs in low- and middle-income countries, and Peru suffers particularly high asthma prevalence. Ambient air exposures are also high, and likely play a role. Most studies of environmental exposures focus on understanding contributors to health care utilization or mortality risk; however, less severe outcomes may still impact quality of life (QOL).

OBJECTIVES

To study the association between multiple pollutants and several asthma domains in Peruvian children.

METHODS

A total of 484 children aged 9-19 years with asthma were followed for 6-9 months, and evaluated for asthma control, asthma-related QOL, missed school days, and health care utilization. We used geographically distributed monitors to estimate air pollutant concentrations and multivariable generalized linear mixed models to model asthma outcomes as a function of pollutants.

RESULTS

A total of 67% of children had moderate to severe persistent asthma. In multipollutant models, higher particulate matter less than 2.5 μm in aerodynamic diameter (PM_2.5), black carbon, and nitrogen dioxide concentrations were independently associated with worse asthma control. For each interquartile range increase in PM_2.5 or nitrogen dioxide concentration, there was a 59% or 34% higher odds of uncontrolled asthma, respectively. If the proportion of PM_2.5 that was black carbon increased, there were increased odds of uncontrolled asthma. Similarly, pollutants were independently associated with worse asthma-related QOL, and PM exposure was associated with increased risk of health care utilization.

CONCLUSIONS

Our study highlights the importance of pollutant exposures on multiple domains of asthma morbidity among Peruvian children, including not only acute exacerbations, but also on general asthma burden, such as worse asthma symptom control and QOL.

Risk factors for asthma among schoolchildren who participated in a case-control study in urban Uganda

Data on asthma aetiology in Africa are scarce. We investigated the risk factors for asthma among schoolchildren (5–17 years) in urban Uganda. We conducted a case-control study, among 555 cases and 1115 controls. Asthma was diagnosed by study clinicians. The main risk factors for asthma were tertiary education for fathers (adjusted OR (95% CI); 2.32 (1.71–3.16)) and mothers (1.85 (1.38–2.48)); area of residence at birth, with children born in a small town or in the city having an increased asthma risk compared to schoolchildren born in rural areas (2.16 (1.60–2.92)) and (2.79 (1.79–4.35)), respectively; father’s and mother’s history of asthma; children’s own allergic conditions; atopy; and cooking on gas/electricity. In conclusion, asthma was associated with a strong rural-town-city risk gradient, higher parental socio-economic status and urbanicity. This work provides the basis for future studies to identify specific environmental/lifestyle factors responsible for increasing asthma risk among children in urban areas in LMICs.

Asthma is a chronic disease of the airways that leads to breathing difficulty and sometimes death: the condition affects about 235 million people worldwide, especially children. Scientists still do not know exactly what causes asthma, but studies in Europe and North America suggest that individuals born or raised in rural areas are less likely to be affected. However, few studies have examined asthma in African countries, where urbanization is often quickly increasing. Examining the factors associated with the disease as more people move to cities may provide new clues about how asthma emerges, and how to prevent it.

To this end, Mpairwe et al. conducted a study with over 1,670 schoolchildren in Uganda. Those born or raised in rural areas were least likely to have asthma, but the risk doubled among children from small towns, and tripled in those born or who grew up in the city. Children whose parents had a higher education and socioeconomic status had the highest asthma risk, but more work is required to understand why this is the case.

The study by Mpairwe et al. is the first step towards identifying environmental and lifestyle factors associated with increased asthma risk in Africa. Further studies may help scientists to understand how beginning life in a more urban area plays a role in the development of the disease.

Urbanisation and asthma in low-income and middle-income countries: a systematic review of the urban-rural differences in asthma prevalence

BACKGROUND

Urbanisation has been associated with temporal and geographical differences in asthma prevalence in low-income and middle-income countries (LMICs). However, little is known of the mechanisms by which urbanisation and asthma are associated, perhaps explained by the methodological approaches used to assess the urbanisation-asthma relationship.

OBJECTIVE

This review evaluated how epidemiological studies have assessed the relationship between asthma and urbanisation in LMICs, and explored urban/rural differences in asthma prevalence.

METHODS

Asthma studies comparing urban/rural areas, comparing cities and examining intraurban variation were assessed for eligibility. Included publications were evaluated for methodological quality and pooled OR were calculated to indicate the risk of asthma in urban over rural areas.

RESULTS

Seventy articles were included in our analysis. Sixty-three compared asthma prevalence between urban and rural areas, five compared asthma prevalence between cities and two examined intraurban variation in asthma prevalence. Urban residence was associated with a higher prevalence of asthma, regardless of asthma definition: current-wheeze OR:1.46 (95% CI:1.22 to 1.74), doctor diagnosis OR:1.89 (95% CI:1.47 to 2.41), wheeze-ever OR:1.44 (95% CI:1.15 to 1.81), self-reported asthma OR:1.77 (95% CI:1.33 to 2.35), asthma questionnaire OR:1.52 (95% CI:1.06 to 2.16) and exercise challenge OR:1.96 (95% CI:1.32 to 2.91).

CONCLUSIONS

Most evidence for the relationship between urbanisation and asthma in LMICs comes from studies comparing urban and rural areas. These studies tend to show a greater prevalence of asthma in urban compared to rural populations. However, these studies have been unable to identify which specific characteristics of the urbanisation process may be responsible. An approach to understand how different dimensions of urbanisation, using contextual household and individual indicators, is needed for a better understanding of how urbanisation affects asthma.

PROSPERO REGISTRATION NUMBER

CRD42017064470.

Household food insecurity is associated with asthma control in Peruvian children living in a resource-poor setting

Rationale: Prior evidence suggests that there may be an association between asthma and food insecurity. We sought to describe the prevalence of food insecurity access, defined as having sufficient resources for appropriate foods in Lima, Peru, and evaluate its association with asthma status and control.Methods: We analyzed data from 553 children with asthma and 268 healthy controls aged nine to 19 years living in two peri-urban communities in Lima, Peru, in 2013. We used the Household Food Insecurity Access Scale to assess food insecurity. We defined uncontrolled asthma as an asthma control test score ≤19. We used multivariable logistic regressions to determine the relationship between asthma outcomes and food insecurity adjusting for age, sex, socioeconomic status, body mass index, and setting.Results: Average age was 14.2 years (SD 2.7). There was a high prevalence of household food insecurity in our study: 330 participants (40.2%) were food insecure, and average food insecurity access score was 2.7 points (SD 4.2). While being food insecure was not associated with asthma status (OR = 1.23, 95% CI 0.85 to 1.79; p = 0.28), it was associated with a higher odds of having uncontrolled asthma (OR = 2.01, 95% CI 1.13 to 3.59; p = 0.02). Each one-unit increase in food insecurity score (higher scores indicating more insecurity) was associated with 8% higher odds of having uncontrolled asthma (OR = 1.08, 95% CI 1.02 to 1.14; p < 0.01).Conclusions: Worse asthma control was associated with food insecurity. Future studies are needed to better understand the role of food security in determining the success of treatment strategies.

The prevalence and persistence of atopic dermatitis in urban United States children

BACKGROUND

Previous studies found that childhood atopic dermatitis (AD) and asthma are associated with residence in urban areas. However, little is known about the prevalence and determinants of AD in US urban populations and its impact on quality-of-life (QOL) and asthma.

OBJECTIVE

To determine AD prevalence and persistence, sociodemographic predictors thereof, and association with QOL and atopic comorbidities in US urban children.

METHODS

We analyzed data from The Fragile Families and Child Wellbeing Study, a prospective cohort study of 4898 women and their children born in 20 large US cities between 1998 and 2000. AD prevalence was determined at ages 5, 9, and 15 years, and stratified by sex, race/ethnicity, and household poverty income level.

RESULTS

The prevalences (95% confidence interval [CI]) of childhood AD were 15.0% (11.0%-18.9%), 15.1% (11.5%-18.7%), and 14.5% (10.4%%-18.5%) at ages 5, 9, and 15 years, respectively. Female sex (multivariable repeated measures logistic regression; adjusted odds-ratio [95% CI]: 1.56 [1.02-2.37]) and black race (1.80 [1.07-3.01]) were associated with persistent AD across all 3 ages. Children with AD at ages 5 and 15 (2.63 [1.42-4.86]), 5, 8 and 15 (1.47 [1.02-2.12]) and 9 and 15 years (1.61 [1.00-2.60]) had higher odds of poor/fair/good overall health. Children with AD at ages 5 and 9 years had the highest odds of ever having asthma (adjusted odds ratio [95% confidence interval]: 6.05 [5.88-6.22]), followed by children with AD at ages 5, 9, and 15 years (3.17 [3.07%-3.27]).

CONCLUSION

Atopic dermatitis prevalence and persistence were highest in US urban children who were female or black. Urban children with persistent AD were more likely to have poor QOL and asthma.

Fine particulate matter (PM2.5) enhances FcεRI-mediated signaling and mast cell function

Persistent exposure to ambient fine particulate matter (PM_2.5) can exacerbate allergic diseases in humans. Mast cells play an important role in allergic inflammation in peripheral tissues, such as skin, mucosa, and lung. Engagement of the high-affinity Fc receptor leads to mast cell degranulation, releasing a variety of highly active mediators including histamine, leukotrienes, and inflammatory cytokines. How PM_2.5 exposure affects mast cell activation and function remains largely unknown. To characterize the effect of PM_2.5 on mast cells, we used bone marrow-derived mast cells (BMMCs) to examine whether PM_2.5 affected FcεRI-mediated signaling, cytokine production, and degranulation. Exposure to high doses of PM_2.5 caused pronounced apoptosis and death of BMMCs. In contrast, exposure to low doses of PM_2.5 enhanced mast cell degranulation and FcεRI-mediated cytokine production. Further analysis showed that PM_2.5 treatment increased Syk activation and subsequently phosphorylation of its substrates including LAT, PLC-γ1, and SLP-76. Moreover, PM_2.5 treatment led to activation of the PI3K and MAPK pathways. Intriguingly, water-soluble fraction of PM_2.5 were found responsible for the enhancement of FcεRI-mediated signaling, mast cell degranulation, and cytokine production. Our data suggest that PM_2.5, mainly water-soluble fraction of PM_2.5, could affect mast cell activation through enhancing FcεRI-mediated signaling.

Epidemiology and risk factors of asthma-chronic obstructive pulmonary disease overlap in low- and middle-income countries

BACKGROUND

Asthma-chronic obstructive pulmonary disease (COPD) overlap (ACO) represents the confluence of bronchial airway hyperreactivity and chronic airflow limitation and has been described as leading to worse lung function and quality of life than found with either singular disease process.

OBJECTIVE

We aimed to describe the prevalence and risk factors for ACO among adults across 6 low- and middle-income countries (LMICs).

METHODS

We compiled cross-sectional data for 11,923 participants aged 35 to 92 years from 4 population-based studies in 12 settings. We defined COPD as postbronchodilator FEV₁/forced vital capacity ratio below the lower limit of normal, asthma as wheeze or medication use in 12 months or self-reported physician diagnosis, and ACO as having both.

RESULTS

The prevalence of ACO was 3.8% (0% in rural Puno, Peru, to 7.8% in Matlab, Bangladesh). The odds of having ACO were higher with household exposure to biomass fuel smoke (odds ratio [OR], 1.48; 95% CI, 0.98-2.23), smoking tobacco (OR, 1.28 per 10 pack-years; 95% CI, 1.22-1.34), and having primary or less education (OR, 1.35; 95% CI, 1.07-1.70) as compared to nonobstructed nonasthma individuals. ACO was associated with severe obstruction (FEV₁ %, <50; 31.6% of ACO vs 10.9% of COPD alone) and severe spirometric deficits compared with participants with asthma (-1.61 z scores FEV₁; 95% CI, -1.48 to -1.75) or COPD alone (-0.94 z scores; 95% CI, -0.78 to -1.10).

CONCLUSIONS

ACO may be as prevalent and more severe in LMICs than has been reported in high-income settings. Exposure to biomass fuel smoke may be an overlooked risk factor, and we favor diagnostic criteria for ACO that include environmental exposures common to LMICs.

Association of traffic air pollution and rhinitis quality of life in Peruvian children with asthma

Background

Air pollution exposure may contribute to rhinoconjunctivitis morbidity in children with underlying airways disease. Prior studies have not assessed rhinoconjunctivitis-related quality of life (QOL) in children with asthma chronically exposed to air pollution.

Methods

Children ages 9–19 years with asthma from peri-urban Peru, self-reporting rhinoconjunctivitis symptoms (n = 484), were administered the Rhinoconjunctivitis QOL Questionnaire (RQLQ) at repeated intervals over one year, with scores dichotomized into bothered (>0) and not bothered (= 0). Individual weekly exposures to particulate matter<2.5μm (PM_2.5) and its black carbon (BC) component were estimated by inverse distance weighted methods. Generalized estimating equations, adjusting for covariates, estimated associations of PM_2.5 and BC with QOL.

Results

Participants were on average 13 years old, 55% female, and majority were atopic (77%). Mean (SD) PM_2.5 and BC concentrations were 21(3.2) μg/m3 and 4.4(1.5) μg/m3, respectively. In adjusted multi-pollutant models, each 10μg/m3 increase in PM_2.5 was associated with increased odds of worse rhinoconjunctivitis QOL (OR;[95% CI]: 1.83;[1.33,2.52]). A 10% increase in the BC proportion was associated with higher rhinitis burden (OR;[95% CI]: 1.80;[1.22,2.66]), while increases in the non-BC component of PM did not significantly impact rhinoconjunctivitis QOL. Associations were similar regardless of atopy.

Conclusion

Higher PM2.5 and BC exposure is associated with worse rhinitis QOL among asthmatic children.

Hygiene practices: Are they protective factors for eczema symptoms?

Introduction

Exact etiology and proper treatment of eczema are still unknown. The hygiene hypothesis and epidermal barrier dysfunction hypothesis attempted to give some plausible explanations for these issues but they still remain unclear. The identification of factors, including hygiene practices, related to eczema symptoms (ES) could shed some light on these matters. Therefore, this study aimed to determine risk factors related to ES and the ES prevalence in two disparate areas in terms of urbanization in Aceh, Indonesia.

Methods

A cross‐sectional study with convenience sampling was conducted among schoolchildren living in urban and rural Aceh. Data on ES, socio‐demographic characteristics, environmental factors, partial ablution and other hygiene related factors were collected by parental questionnaires. In addition, children's anthropometric measurements were also collected.

Results

The prevalence of current ES in the study population was 21%. When stratifying by residency, the prevalence of ES in urban and rural area was 20.93% versus 21.05%. Partial ablution was independently associated with a reduced risk of ES (OR = 0.36; 95% CI 0.13–0.96). Important risk factors for ES were paternal history of allergic disease (OR = 4.09%; 95% CI 1.51–11.11) and belonging to the older group of schoolchildren (10–13 years old) (OR = 2.57; 95% CI 1.03–6.40).

Conclusions

There were no significant differences in the prevalence of ES between urban and rural settings, and partial ablution had a protective effect on ES. These findings support the epidermal barrier dysfunction hypothesis as a possible pathway of eczema.

Asthma and Allergic Disorders in Uganda: A Population-Based Study Across Urban and Rural Settings

BACKGROUND

Allergic diseases are increasing in sub-Saharan Africa, but few studies have characterized the burden among adults.

OBJECTIVE

We conducted a study to evaluate the prevalence and risk factors of allergic disorders in urban and rural Uganda.

METHODS

We present a cross-sectional analysis of enrollment data from a population-based cohort study of adults aged ≥35 years in urban and rural Uganda. Sociodemographic and both lifetime and 12-month respiratory symptoms data were collected and spirometry was conducted following standard guidelines.

RESULTS

In 1,308 adults (median age 43.8 years and 52.3% female), we found an age-adjusted prevalence of 6.8% for asthma (9.8% urban, 4.3% rural; P < .001), 11.9% for allergic rhinitis (16.4% urban, 7.8% rural; P < .001), and 8.2% for eczema (9.9% urban, 7.8% rural; P = .15). Urbanization was the primary driver of asthma, accounting for 61.4% of cases (95% confidence interval [CI] 22.0% to 83.4%), and was the strongest risk factor for any allergic illness (odds ratio [OR] = 1.87, 95% CI 1.39-2.51). Parental asthma was not associated with allergic illness. Asthma was associated with a lower forced expiratory volume in 1 second (FEV₁) by 0.56 z scores (95% CI 0.33-0.80). We found a dose-response association between lower quintiles of the FEV₁/forced vital capacity ratio and both hospitalization (OR = 1.77, 95% CI 1.21-2.59) and impairment in daily activities (1.65, 1.20-2.27).

CONCLUSIONS

Asthma and allergic rhinitis were twice as prevalent in urban settings. Asthma was associated with greater impairment and worse lung function outcomes. We identified a high prevalence of allergic disorders in Uganda, which can be expected to increase due to urbanization and resultant exposures throughout early development.

Serum folate concentrations, asthma, atopy, and asthma control in Peruvian children

BACKGROUND

The relationship between folate status and asthma-related outcomes has not been carefully examined in low- and middle-income countries where folate deficiency is common.

METHODS

Ancillary analysis of an unmatched case-control study in which we analyzed serum folate concentrations in 412 children with asthma and 342 controls living in peri-urban communities in Lima, Peru. We examined baseline associations between folate and asthma, atopy, total serum IgE, pulmonary function, and fractional exhaled nitric oxide. We then followed children with asthma longitudinally for 6-9 months and assessed associations between folate and odds of uncontrolled asthma (defined as Asthma Control Test score ≤ 19) and of ≥1 emergency visits during follow-up.

RESULTS

A 10 ng/mL decrease in serum folate was associated with 45% higher adjusted odds of asthma (OR = 1.45, 95% CI 1.05-2.02). The folate-asthma relationship differed by atopic status: a 10 ng/mL decrease in serum folate was associated with a 2.4-fold higher odds of asthma among children without atopy (2.38, 1.20-4.72) and 23% higher odds of asthma in children with atopy (1.23, 0.85-1.80). Among children with asthma, a 10 ng/mL decrease in serum folate was associated with 62% higher odds of uncontrolled asthma (1.62, 1.02-2.56) and 73% higher odds of ≥1 emergency visits during follow-up (1.73, 1.05-2.85).

CONCLUSIONS

Serum folate concentrations were inversely associated with asthma, but this effect was stronger in children without atopy. Among children with asthma, lower serum folate concentrations were associated with higher risk of uncontrolled asthma.

Associations between serum 25(OH)D concentrations and prevalent asthma among children living in communities with differing levels of urbanization: a cross-sectional study

Background

Prior evidence suggests that vitamin D deficiency may increase the risk of asthma and atopy and impair pulmonary function in children.

Methods

In this cross-sectional analysis nested in a case-control study, we analyzed serum 25(OH)D concentrations in 413 children with asthma and 471 children without asthma living in two geographically adjacent study communities (Pampas and Villa El Salvador). We measured total and antigen-specific IgE levels, pulmonary function, asthma control, and exhaled nitric oxide.

Results

Mean 25(OH)D concentrations were 25.2 ng/mL (SD 10.1) in children with asthma and 26.1 ng/mL (SD 13.7) in children without asthma (p = 0.28). Vitamin D deficiency (25(OH)D < 20 ng/ml) was more common in Pampas than in Villa El Salvador (52.7% vs. 10.5%; p < 0.001). In the overall study population, a 10 ng/ml decrease in serum 25(OH)D concentrations was not significantly associated with odds of asthma (OR 1.09, 95% CI: 0.94 to 1.25). However, vitamin D deficiency was associated with a 1.6-fold increase in odds of asthma in the overall cohort (95% CI: 1.14 to 2.25). After stratifying by site, a 10 ng/mL decrease in serum 25(OH)D concentrations was associated with 18% higher odds of having asthma in Pampas (OR = 1.18, 95% CI 1.02 to 1.38), whereas there was no significant association between 25(OH)D concentrations and asthma in Villa El Salvador (OR = 0.95, 95% CI 0.87 to 1.05). Combined data from these geographically adjacent populations suggests a possible threshold for the relationship between 25(OH)D levels and asthma at approximately 27.5 ng/ml. Serum 25(OH)D concentrations were not clearly associated with asthma control, total serum IgE, atopy, or airway inflammation.

Conclusion

Serum 25(OH)D concentrations were inversely associated with asthma in one study community with a high prevalence of deficiency. Studies are needed to investigate a possible threshold 25(OH)D concentration after which higher vitamin D levels show no further benefit for asthma.

Electronic supplementary material

The online version of this article (doi:10.1186/s40733-017-0033-2) contains supplementary material, which is available to authorized users.

The Global Epidemiologic Transition: Noncommunicable Diseases and Emerging Health Risk of Allergic Disease in Sub-Saharan Africa

Globally, there has been a shift in the causes of illness and death from infectious diseases to noncommunicable diseases. This changing pattern has been attributed to the effects of an (ongoing) epidemiologic transition. Although researchers have applied epidemiologic transition theory to questions of global health, there have been relatively few studies exploring its relevance especially in the context of emerging allergic disorders in sub-Saharan Africa (SSA). In this article, we address the growing burden of noncommunicable diseases in sub-Saharan Africa through the lens of epidemiologic transition theory. After a brief review of the literature on the evolution of the epidemiologic transition with a particular emphasis on sub-Saharan Africa, we discuss existing frameworks designed to help inform our understanding of changing health trends in the developing world. We subsequently propose a framework that privileges "place" as a key construct informing our understanding. In so doing, we use the example of allergic disease, one of the fastest growing chronic conditions in most parts of the world.

Urbanization is associated with increased asthma morbidity and mortality in Brazil

INTRODUCTION

Previous cross-sectional studies could establish an association between prevalence of self-reported wheeze and urban-rural environment, but the impact of urbanization on meaningful outcomes of asthma for public health is not established yet.

OBJECTIVES

Evaluate the effect of urbanization on asthma burden.

METHODS

A time series study of 5,505 Brazilian municipalities. The unit of analysis was the municipality. Two time frames were evaluated: from 1999 to 2001 and from 2009 to 2011. Trends from the first to the second time frame were evaluated. Governmental databases were the source of information. Multivariate binary logistic regression models were used.

RESULTS

In the age range from 5 to 24 years old, municipalities with increase in the proportion of individuals living in urban area had lower odds to reduce hospital admission rate from asthma (OR: .93) and lower odds to reduce death rate from asthma (OR: .88). In the age range from 25 to 39 years old, municipalities with increase in the proportion of individuals living in urban area had lower odds to reduce hospital admission rate from asthma (OR: .93) and lower odds to reduce death rate from asthma (OR: .82). Municipalities that increased access to physicians and that supplied inhaled corticosteroids free of charge for asthma since year 2003 had increased odds to reduce hospital admission and death rates from asthma.

CONCLUSIONS

Increase in urban population was associated with lower odds to reduce hospital admission and death rates from asthma in children and young adults living in a transition society.

Particularities of allergy in the Tropics

Allergic diseases are distributed worldwide and their risk factors and triggers vary according to geographical and socioeconomic conditions. Allergies are frequent in the Tropics but aspects of their prevalence, natural history, risk factors, sensitizers and triggers are not well defined and some are expected to be different from those in temperate zone countries. The aim of this review is to investigate if allergic diseases in the Tropics have particularities that deserve special attention for research and clinical practice. Such information will help to form a better understanding of the pathogenesis, diagnosis and management of allergic diseases in the Tropics. As expected, we found particularities in the Tropics that merit further study because they strongly affect the natural history of common allergic diseases; most of them related to climate conditions that favor permanent exposure to mite allergens, helminth infections and stinging insects. In addition, we detected several unmet needs in important areas which should be investigated and solved by collaborative efforts led by the emergent research groups on allergy from tropical countries.

Characteristics of traditional Chinese medicine users and prescription analysis for pediatric atopic dermatitis: a population-based study

Background

Atopic dermatitis among children is an important issue due to relapses and skin manifestations. Traditional Chinese medicine (TCM) is commonly used to treat children with atopic dermatitis. The aim of this study was to investigate the characteristics and TCM prescriptions of patients with atopic dermatitis using a nationwide database.

Methods

Children younger than 12 years of age diagnosed with atopic dermatitis, defined as ICD-9-CM codes 691.8 and 692.x, were identified from the database. Data on age, diagnosis codes, area of residence and use of corticosteroids of the TCM users were recorded. Association rule mining was used to analyze the prescriptions used for atopic dermatitis.

Results

We identified 13,646 children with atopic dermatitis using TCM in 2007. Female gender (OR: 0.83 for male gender), adolescence (OR: 10.0, 95 % CI: 8.88–11.15) and allergic rhinitis (OR: 2.44, 95 % CI: 2.10–2.85) were associated with the use of TCM. Fewer of the TCM users were prescribed with corticosteroids (35.8 % of all TCM users), but the TCM users had a higher rate of long-term topical corticosteroid therapy (10.6 % for TCM users versus 2.0 % for those who did not use TCM). Chinese herbal medicine (CHM) was used by 93.7 % of all TCM users in 36,398 prescriptions. On average, 5.6 kinds of CHM were used in combination. The relationship between the CHMs constituted a network, in which Xiao-Feng-San was the core treatment for atopic dermatitis.

Conclusions

In this study, we described the characteristics of children with atopic dermatitis who use TCM in Taiwan. and identified the core CHM treatment. Further research on the safety and efficacy of this treatment are still needed.

Effect of cigarette smoke on counts of immunoreactive cells to eotaxin-1 and eosinophils on the nasal mucosa in young patients with perennial allergic rhinitis

Introduction

In teenagers with perennial allergic rhinitis, exposure to tobacco cigarette smoke increases the count of eosinophils in the nasal mucosa; the recruitment of eosinophils arises from the combined action of a number of cellular and molecular signals, including eotaxin.

Objective

To assess the effect of exposure to tobacco cigarette smoke on the count of immunoreactive cells to eotaxin-1 and eosinophils on the nasal mucosa of children and teenagers with perennial allergic rhinitis.

Methods

In a cross-sectional study, forty-four patients were evaluated (aged 7–19 years old): 22 with and 22 with no exposure to tobacco cigarette smoke. After replying to 2 validated questionnaires, on Asthma and Allergies in Childhood and on the severity of nasal symptoms, nasal mucosal samples were obtained by scraping the middle one-third of the inferior turbinates. Then counts of immunoreactive cells to eotaxin-1 and eosinophils were assessed by immunohistochemistry.

Results

Patients with exposure to tobacco cigarette smoke showed higher cell counts of both eotaxin-1 and eosinophils than patients with no exposure to the smoke, with no correlation between the two variables. However, both counts, of eotaxin-1 and eosinophils, were related to the cotinine/creatinine ratio.

Conclusions

Exposure to tobacco cigarette smoke can increase eotaxin-1 and the count of eosinophils in the nasal mucosa of young patients with perennial allergic rhinitis.

Urbanisation but not biomass fuel smoke exposure is associated with asthma prevalence in four resource-limited settings

BACKGROUND

Urbanisation is an important contributor to the prevalence of asthma worldwide, and the burden of this effect in low-income and middle-income countries undergoing rapid industrialisation appears to be growing. We sought to characterise adult asthma prevalence across four geographically diverse settings in Peru and identify both individual and environmental risk factors associated with adult asthma.

METHODS

We collected sociodemographics, clinical history and spirometry in adults aged ≥35 years. We defined asthma as meeting one of the three criteria: physician diagnosis, self-report of wheezing attack or use of asthma medications. We used multivariable logistic regression to assess individual and environmental factors associated with adult asthma.

RESULTS

We analysed data from 2953 participants (mean age 55 years; 49% male). Overall asthma prevalence was 7.1%, which varied with urbanisation: highest in Lima (14.5%), followed by urban Puno (4.0%), semiurban Tumbes (3.8%) and rural Puno (1.8%). In multivariable analysis, being male (OR=0.60, 95% CI 0.39 to 0.93) and living at high altitude (OR=0.26, 95% CI 0.16 to 0.42) were associated with lower odds of having asthma, whereas living in an urban setting (OR=4.72, 95% CI 3.15 to 7.23) and family history of asthma (OR=1.83, 95% CI 1.19 to 2.73) were associated with higher odds. Current daily exposure to biomass fuel smoke (OR=1.18, 95% CI 0.70 to 1.91) and smoking (OR=0.99, 95% CI 0.73 to 1.22) were not associated with asthma.

CONCLUSIONS

These findings confirm that urbanisation is an environmental risk factor of asthma, questions biomass fuel smoke exposure as an important risk factor and proposes high altitude as possibly protective against the development of asthma.