Influence of poverty and infection on asthma in Latin America

Asthma symptoms, spirometry and air pollution exposure in schoolchildren in an informal settlement and an affluent area of Nairobi, Kenya

BACKGROUND

Although 1 billion people live in informal (slum) settlements, the consequences for respiratory health of living in these settlements remain largely unknown. This study investigated whether children living in an informal settlement in Nairobi, Kenya are at increased risk of asthma symptoms.

METHODS

Children attending schools in Mukuru (an informal settlement in Nairobi) and a more affluent area (Buruburu) were compared. Questionnaires quantified respiratory symptoms and environmental exposures; spirometry was performed; personal exposure to particulate matter (PM2.5) was estimated.

RESULTS

2373 children participated, 1277 in Mukuru (median age, IQR 11, 9-13 years, 53% girls), and 1096 in Buruburu (10, 8-12 years, 52% girls). Mukuru schoolchildren were from less affluent homes, had greater exposure to pollution sources and PM2.5. When compared with Buruburu schoolchildren, Mukuru schoolchildren had a greater prevalence of symptoms, 'current wheeze' (9.5% vs 6.4%, p=0.007) and 'trouble breathing' (16.3% vs 12.6%, p=0.01), and these symptoms were more severe and problematic. Diagnosed asthma was more common in Buruburu (2.8% vs 1.2%, p=0.004). Spirometry did not differ between Mukuru and Buruburu. Regardless of community, significant adverse associations were observed with self-reported exposure to 'vapours, dusts, gases, fumes', mosquito coil burning, adult smoker(s) in the home, refuse burning near homes and residential proximity to roads.

CONCLUSION

Children living in informal settlements are more likely to develop wheezing symptoms consistent with asthma that are more severe but less likely to be diagnosed as asthma. Self-reported but not objectively measured air pollution exposure was associated with increased risk of asthma symptoms.

Asthmatic Symptoms in Children and Adolescents: the Role of Maternal Experiences of Racial Discrimination

Emerging evidence suggests that vicarious racial experiences of discrimination may negatively influence child health. Few studies have focus on childhood asthma symptoms and potential moderators of such relationship.

METHODS

We used two population-based cross-sectional studies from the Social Change Allergy and Asthma in Latin America project in Salvador, Brazil. A total of 1003 children and mothers interviewed in 2006 were included, of whom 873 were reached again in 2013. Vicarious racial discrimination was assessed in mothers by applying the Experiences of Discrimination scale. Data on wheeze and environmental exposures were collected with standardized questionnaires. Levels of allergen-specific IgE were measured to identify atopy. Generalized estimating equations were used to estimate the association between maternal discrimination and wheezing and asthma phenotypes. Interaction terms were evaluated to identify whether mothers' mental health and family social support modified such associations.

RESULTS

Children whose mothers reported racial discrimination had greater odds of have asthma symptoms (OR 1.75; 95% CI 1.15-2.67) and non-atopic asthma (OR 1.92; 95% CI 1.09-3.40). When we considered effect modification by social support, we found a higher ORs when the level of social support was lower (OR 2.43; 95% IC 1.19-4.97) than when the level of social support was higher (OR 1.12; CI 0.64-1.96).

CONCLUSION

Maternal discrimination was associated with asthma symptoms and with non-atopic phenotype among their children. Enjoying wider social support network appears to buffer the effect on asthmatic symptoms. Intervention on childhood asthma needs to incorporate strategies that target the family.

Genetic polymorphisms in vitamin D pathway influence 25(OH)D levels and are associated with atopy and asthma

Background

Vitamin D deficiency or insufficiency, has been associated with atopy and lack of asthma control. Our objective was to investigate associations between variants in genes of vitamin D pathway with serum levels of 25-hydroxyvitamin D (25(OH)D), atopy, asthma and asthma severity in teenagers from Northeast Brazil.

Methods

This is a cross sectional study nested in a cohort population of asthma. 25(OH)D was quantified from 968 of 11–17 years old individuals by ELISA. Asthma diagnosis was obtained by using the ISAAC Phase III questionnaire. Specific IgE was determined by ImmunoCAP; genotyping was performed using the 2.5 HumanOmni Biochip from Illumina. Statistical analyses were performed in PLINK 1.07 and SPSS 22.1.

Results

After quality control, 104 Single Nucleotides Variants (SNVs) in vitamin D pathway genes, typed in 792 individuals, were included in the analysis. The allele A of rs10875694 on VDR was positively associated with atopy (OR = 1.35; 95% CI 1.01–1.81). The allele C of rs9279 on VDR, was negatively associated with asthma risk (OR = 0.66; 95% CI 0.45–0.97), vitamin D insufficiency (OR = 0.78; 95% CI 0.70–0.96) and higher VDR expression. Two variants in VDR were associated with asthma severity, the allele A of rs2189480 (OR = 0.34; 95% CI 0.13–0.89) and the allele G of rs4328262 (OR = 3.18; 95% CI 1.09–9.28). The combination of variants in CYP2R1 and CYP24A1 (GAC, to rs10500804, rs12794714 and rs3886163, respectively) was negatively associated with vitamin D production (β = − 1.24; 95% CI − 2.42 to − 0.06).

Conclusions

Genetic variants in the vitamin D pathway affect vitamin D serum levels and, thus, atopy and asthma.

Soil-transmitted helminth parasites and allergy: Observations from Ecuador

There is considerable interest as to potential protective effects of soil-transmitted helminths (STH) against allergy and allergic diseases. Here, we discuss findings of studies done of the effects of STH parasites on atopy and allergic diseases in Ecuador. While cross-sectional studies have consistently shown a reduced prevalence of allergen skin prick test (SPT) reactivity among infected schoolchildren, the removal of these infections by repeated deworming did not affect SPT prevalence over the short-term (ie, 12 months) but may have increased SPT prevalence over the long-term (ie, 15-17 years). In the case of allergic symptoms, cross-sectional studies have generally not shown associations with STH and intervention studies showed no impact on prevalence. However, a birth cohort suggested that early STH infections might reduce wheeze by 5 years. Allergic sensitization to Ascaris, however, explained a significant proportion of wheezing among rural schoolchildren. Studies of the effects of STH on immune and inflammatory responses indicated a potential role of STH in contributing to more robust regulation. The effects of STH on allergy are likely to be determined by history of exposure over the life-course and by interactions with a wide variety of other infectious and non-infectious factors.

Variants in the IL17 pathway genes are associated with atopic asthma and atopy makers in a South American population

BACKGROUND

Asthma is a complex disorder with multiple phenotypes which can influence its severity and response to treatment. The TH17 lymphocytes producing IL-17A and IL17-F cytokines, may have a role on asthma inflammation. The aim of our study was to evaluate the association between genetic variants in IL17 pathway genes with asthma and atopy markers.

MATERIALS AND METHODS

Genotyping was performed using a commercial panel in 1245 participants of SCAALA cohort. The study included 91 SNVs in IL-17 pathway genes. Logistic regressions for asthma and atopy markers were performed using PLINK 1.9. In silico analyses were performed using rSNPbase, RegulomeDB, and Gtex portal for in silico gene expression.

RESULTS AND DISCUSSION

The T allele of rs1974226 in IL17A was positively associated with asthma (OR: 1.37; 95% CI 1.02-1.82). Also, the T allele of rs279548 was positively associated with asthma (OR: 1.30; 95% CI 1.02-1.64), atopy (OR: 1.62; 95% CI 1.05-2.50) and increased expression of the IL17RC in lung and whole blood tissues. The others genetic variants in the IL17 pathways genes were associated with both protection and risk for asthma development as well as with IgE levels.

CONCLUSION

The genetic variants in IL-17-related genes are associated with the atopic asthma phenotype and IgE production.

Cardiovascular and other risk factors among people who live in slums in Buenos Aires, Argentina

OBJECTIVES

Effective planning of health policies requires the availability of accurate data, representing the burden of disease and risks to the diverse components of society. In Argentina, health information comes from the national risk factors survey (NRFS), which characterises the distribution of different risk factors. However, the NRFS has never collected information from residents living in slums, despite slums representing 10% of the population. The objective of this survey was to characterise the prevalence of cardiovascular and other risk factors among the inhabitants of one of the largest slums in Buenos Aires (Villa 31) and compare it to data from the NRFS.

STUDY DESIGN

This was a cross-sectional study.

METHODS

A cross-sectional study was carried out in 400 slum households, using the same data structure as the NRFS. The survey obtained information about economic aspects, reproductive health, addictions and risk factors. All participants had their blood pressure, weight and height measured. A total of 406 people were interviewed and their data were compared with data from 32,365 people in the NRFS. All comparisons were made on the basis of age group.

RESULTS

A fair/poor self-perceived level of health (odds ratio [OR] 3.19, 95% confidence interval [CI]: 2.60-3.91), anxiety and moderate to severe depression (OR 5.44, 95% CI: 4.43-6.69), problem drinking (OR 10.01, 95% CI 8.08-12.40), self-reported hypertension (OR 1.26, 95% CI: 1.01-1.57), overweight (OR 1.26, 95% CI: 1.03-1.55) and obesity (OR 1.72, 95% CI: 1.38-2.15) were significantly higher in the slum population. In people aged 18-24 years, the prevalence of diabetes was triple the national average (OR 3.17, 95% CI: 1.26-7.98). For all evaluated conditions in this study, the inhabitants of the slum received significantly less treatment compared with participants from the NRFS.

CONCLUSIONS

The prevalence of cardiovascular and other risk factors in the slum population has a different distribution to that reported in the NRFS. These data suggest the need to establish specific policies for slum populations.

Social, Environmental and Behavioral Determinants of Asthma Symptoms in Brazilian Middle School Students-A National School Health Survey (Pense 2012)

Biological and psychosocial factors are recognized contributors to the worldwide burden of asthma. However, the relationship between psychosocial factors and asthma symptoms among students in low- and middle-income countries remains underexplored. We aimed to identify socioeconomic, environmental, psychosocial, family-related and lifestyle factors associated with the self-reporting of asthma symptoms in Brazilian adolescents. This is a cross-sectional study using data from the 2012 PeNSE survey (n = 109,104). We analyzed the following variables: socioeconomic conditions, demographic characteristics, lifestyle, family context and dynamics, psychosocial indicators, smoking, and exposure to violence. Our outcome variable was the self-report of asthma symptoms in the past 12 months. The prevalence of wheezing was 22.7% (21.5–23.9). After adjusting for sex, age and the variables from higher hierarchical levels, exposure to violence (feeling unsafe at school, being frequently bullied, being exposed to fights with firearms) and physical aggression by an adult in the family were the environmental factors that showed the strongest associations with self-reporting of asthma symptoms. For psychosocial indicators of mental health and social integration, feelings of loneliness and sleeping problems were the strongest factors, and among individual behavioral factors, the largest associations were found for tobacco consumption. Our findings were consistent with previous studies, showing an association between self-reported asthma symptoms and socio-economic status, family context and dynamics, psychosocial indicators of mental health, exposure to violence and social integration, as well as a sedentary lifestyle and tobacco use.

Asthma trend in adolescence in Brazil: results of the National Adolescent School-based Health Survey (PeNSE 2012-2015)

OBJECTIVE

To compare the evolution of asthma indicators in the editions of the National School Health Survey (PeNSE 2012 and 2015).

METHODS

Cross-sectional study including Brazilian 9th grade students from public and private schools. Wheezing was assessed through the question: "In the past 12 months, did you have wheezing (or chirping) chest? (yes/no)", and to assess lifetime presence of asthma, the question was "Have you ever had asthma? (yes/no)".

RESULTS

Of the students, 23,52% reported wheezing or chirping chest in the past 12 months, with prevalences ranging from 16,80% (in Salvador, Bahia) to 27,43% (in Porto Alegre, Rio Grande do Sul). Lifetime presence of asthma was reported by 17,92% of the students, ranging from 13,98% (in Campo Grande, Mato Grosso do Sul) to 30,35% (in Porto Alegre, Rio Grande do Sul). There was also a decrease in the prevalence of self-report of wheezing/chirping chest in the last 12 months between the two editions of the survey (2012/2015) in 20 of the 27 Brazilian state capitals, especially in Belo Horizonte, Florianópolis, Cuiabá and Goiânia. However, prevalence of lifetime diagnostic of asthma increased from 2012 to 2015 in 26 of the 27 Brazilian state capitals.

CONCLUSION

There was a decrease in the prevalence of self-report of asthma symptoms and an increase of self-reported lifetime presence of asthma. Certainly, monitoring indicators of asthma prevalence is of high importance for health knowledge and the development of public policies.

Associations between infant fungal and bacterial dysbiosis and childhood atopic wheeze in a nonindustrialized setting

BACKGROUND

Asthma is the most prevalent chronic disease of childhood. Recently, we identified a critical window early in the life of both mice and Canadian infants during which gut microbial changes (dysbiosis) affect asthma development. Given geographic differences in human gut microbiota worldwide, we studied the effects of gut microbial dysbiosis on atopic wheeze in a population living in a distinct developing world environment.

OBJECTIVE

We sought to determine whether microbial alterations in early infancy are associated with the development of atopic wheeze in a nonindustrialized setting.

METHODS

We conducted a case-control study nested within a birth cohort from rural Ecuador in which we identified 27 children with atopic wheeze and 70 healthy control subjects at 5 years of age. We analyzed bacterial and eukaryotic gut microbiota in stool samples collected at 3 months of age using 16S and 18S sequencing. Bacterial metagenomes were predicted from 16S rRNA data by using Phylogenetic Investigation of Communities by Reconstruction of Unobserved States and categorized by function with Kyoto Encyclopedia of Genes and Genomes ontology. Concentrations of fecal short-chain fatty acids were determined by using gas chromatography.

RESULTS

As previously observed in Canadian infants, microbial dysbiosis at 3 months of age was associated with later development of atopic wheeze. However, the dysbiosis in Ecuadorian babies involved different bacterial taxa, was more pronounced, and also involved several fungal taxa. Predicted metagenomic analysis emphasized significant dysbiosis-associated differences in genes involved in carbohydrate and taurine metabolism. Levels of the fecal short-chain fatty acids acetate and caproate were reduced and increased, respectively, in the 3-month stool samples of children who went on to have atopic wheeze.

CONCLUSIONS

Our findings support the importance of fungal and bacterial microbiota during the first 100 days of life on the development of atopic wheeze and provide additional support for considering modulation of the gut microbiome as a primary asthma prevention strategy.

Prevalence and factors associated with asthma in students from Montes Claros, Minas Gerais, Brazil

We investigated the prevalence of asthma and factors related to asthma development in schoolchildren aged 6 to 14, living in central and peripheral areas of the city of Montes Claros, Minas Gerais and who were registered with the Family Health Strategy program. Initially, a standard written questionnaire, based on ISAAC (International Study of Asthma and Allergies in Childhood), was administered to collect personal data, information regarding income, asthma prevalence, allergic rhinitis and eczema (N = 1,131). Secondly, a case-control study was performed by grouping the patients as either asthmatic (A; N = 172) or non-asthmatic (NA; N = 379). Potential factors associated with the occurrence of asthma were evaluated using the complementary questionnaire from ISAAC phase II. Skin tests for immediate hypersensitivity (STIH) and parasitological tests were also performed. The odds ratio, estimated by multivariate analysis, indicated that asthma cases were related to kindergarten attendance, household smoking, family history of asthma, rhinitis and positive STIH. It was concluded that, in the studied population, the prevalence of asthma was related to genetic predisposition, in addition to individual history, social demographics, exposure to pollutants such as tobacco smoke and a positive response to allergy testing.

Association of Serum Lipids and Obstructive Lung Disease in Hispanic/Latino Adults of Diverse Backgrounds

Rationale

Substantial variation in the prevalences of obstructive lung disease exist between Hispanic/Latino heritage groups. Experimental studies have posited biological mechanisms linking serum lipids and lipid-lowering medications with obstructive lung disease. The aim of this study is to examine the associations of serum lipid levels with the prevalences of asthma and chronic obstructive pulmonary disease in the Hispanic Community Health Study/Study of Latinos and how these associations vary by Hispanic/Latino heritage group.

Methods

The Hispanic Community Health Study/Study of Latinos is a population-based probability sample of 16,415 self-identified Hispanic/Latino persons aged 18–74 years recruited between 2008 and 2011 from randomly selected households in four US field centers. The baseline clinical examination included comprehensive biological testing (fasting serum lipid levels), behavioral and socio-demographic assessments, medication inventory including inhalers, and respiratory data including questionnaires for asthma and standardized spirometry with post-bronchodilator measures for identification of obstructive lung disease.

Measurements and main results

Hispanic/Latinos with current asthma had lower age- and statin-use-adjusted mean serum total cholesterol, low-density lipoprotein cholesterol, and triglyceride levels than their non-asthmatic counterparts. In analysis adjusted for age plus gender, ethnicity, cigarette smoking, alcohol intake, body mass index, lipid/cholesterol-lowering medications, age at immigration, health insurance status, and use of oral corticosteroids, increasing serum levels of total cholesterol and low-density lipoprotein cholesterol were associated with lower odds of current asthma in the estimated population. Unlike asthma, Hispanic/Latinos with chronic obstructive pulmonary disease had lower mean high-density lipoprotein than their non- chronic obstructive pulmonary disease counterparts. In the fully adjusted analysis no significant associations were found between lipid levels and prevalent chronic obstructive pulmonary disease.

Conclusions

We showed a modest inverse relationship between serum lipid levels and current asthma. These results highlight some important differences in Hispanics/Latinos and certain serum lipids may be factors or markers of obstructive lung disease.

The history, geography, and sociology of slums and the health problems of people who live in slums

Massive slums have become major features of cities in many low-income and middle-income countries. Here, in the first in a Series of two papers, we discuss why slums are unhealthy places with especially high risks of infection and injury. We show that children are especially vulnerable, and that the combination of malnutrition and recurrent diarrhoea leads to stunted growth and longer-term effects on cognitive development. We find that the scientific literature on slum health is underdeveloped in comparison to urban health, and poverty and health. This shortcoming is important because health is affected by factors arising from the shared physical and social environment, which have effects beyond those of poverty alone. In the second paper we will consider what can be done to improve health and make recommendations for the development of slum health as a field of study.

Socioeconomic and environmental determinants of adolescent asthma in urban Latin America: an ecological analysis

The prevalence of asthma is high in urban areas of many Latin-American countries where societies show high levels of inequality and different levels of development. This study aimed to examine the relationship between asthma symptoms prevalence in adolescents living in Latin American urban centers and socioeconomic and environmental determinants measured at the ecological level. Asthma prevalence symptoms were obtained from the International Study of Asthma and Allergies in Childhood (ISAAC) phase III. A hierarchical conceptual framework was defined and the explanatory variables were organized in three levels: distal, intermediate, proximal. Linear regression models weighed by sample size were undertaken between asthma prevalence and the selected variables. Asthma prevalence was positively associated with Gini index, water supply and homicide rate, and inversely associated with the Human Development Index, crowding and adequate sanitation. This study provides evidence of the potential influence of poverty and social inequalities on current wheezing in adolescents in a complex social context like Latin America.

Prevalence of asthma symptoms among adolescents in Brazil: National Adolescent School-based Health Survey (PeNSE 2012)

OBJECTIVE

This study aims to describe the prevalence rates of asthma symptoms in Brazil, its Regions and State capitals, according to data from the National Adolescent School-based Health Survey, 2012. Furthermore, it aims to compare the prevalence of asthma in the capitals evaluated by PeNSE 2012 with previous results of the International Study of Asthma and Allergies in Childhood (ISAAC).

METHODS

Cross sectional study of 9th grade students at public and private schools of all Brazilian states and the Federal District (Brasília). A self reported questionnaire containing items from the ISAAC was applied in order to identify the presence of asthma symptoms.

RESULTS

The results of PeNSE indicate a high prevalence of asthma symptoms (23.2%) and of reports of a previous medical diagnosis of asthma (12.4%). Of the five state capitals in which the PeNSE results were compared to the ISAAC, São Paulo, Curitiba and Porto Alegre presented an increase in the prevalence of asthma symptoms. In Salvador, there was a reduction.

CONCLUSION

Brazil is among the countries with the highest prevalence of asthma in the world, and the prevalence is still growing.

The effect of internalization and other psychologic factors on the remission and severity of wheeze in children

BACKGROUND

Asthma prevalence in Latin America is high and continues to increase. There is evidence that the psychologic characteristics of the child are associated with greater asthma morbidity. This study aimed to investigate the independent effect of internalizing/externalizing problems on two asthma/wheeze outcomes: (i) remission and (ii) progression to severity on Latin American children with mild asthma symptoms at baseline.

METHODS

This was a prospective study in a cohort of 371 asthmatic children living in a poor urban area in Salvador, Brazil. The psychologic characteristics of the child were assessed using the Child Behavior Checklist (CBCL), and wheezing was defined using the ISAAC questionnaire at the start and end of follow-up. A multiple logistic regression model with random effects was used to examine the association between the psychologic components and both outcomes.

RESULTS

Remission of symptoms of wheeze was observed among 229 (61.73%) children. Remission was 56% lower among children with internalizing problems (OR = 0.54, 95% CI 0.33-0.87, p = 0.01). In addition, we found that 19 (8.76%) of the children acquired severe symptoms during follow-up and there was strong evidence of the effect of internalizing problems in increasing the risk of progression to severe wheeze symptoms (OR = 4.03, 95% CI 1.39-11.70, p = 0.01).

CONCLUSIONS

Children with internalizing problems but not externalizing had less remission of wheezing, and a higher risk of acquiring severe symptoms. These results highlight the importance of psychologic care for children with asthma, to improve the prognosis of this condition.

Bibliometric analysis of medicine-related publications on poverty (2005-2015)

BACKGROUND

Poverty is a global problem. The war against poverty requires not only financial support, but also poverty-related research to pinpoint areas of high need of intervention. In line with international efforts to fight poverty and negative consequences, we carried out this study to give a bibliometric overview of medicine-related literature on poverty. Such a s study is an indicator of the extent of interaction of various international key players on the war against poverty-related health problems.

METHODS

Scopus was used to achieve the objective of this study. The time span set for this study was 2005-2015. Poverty-related articles under the subject area "Medicine" were used to give bibliometric indicators such as annual growth of publications, international collaboration, highly cited articles, active countries, institutions, journals, and authors.

RESULTS

The total number of retrieved articles was 1583. The Hirsh-index of retrieved articles was 56. A modest and fluctuating increase was seen over the study period. Visualization map of retrieved articles showed that "HIV", infectious diseases, mental health, India, and Africa were most commonly encountered terms. No significant dominance of any particular author or journal was observed in retrieved articles. The United States of America had the largest share in the number of published articles. The World Health Organization and Centers for Disease Prevention and Control were among top active institutions/organizations. International collaboration was observed in less than one third of publications. Top cited articles focused on three poverty-related health issues, mainly, infectious diseases, malnutrition, and child development/psychology. Most of top articles were published in high impact journals.

CONCLUSIONS

Data indicated that articles on poverty were published in high influential medical journals indicative of the importance of poverty as a global health problem. However, the number publications and the extent of international collaborations was lower than expected given the huge burden of poverty-related health problems.

The association of intrafamilial violence against children with symptoms of atopic and non-atopic asthma: A cross-sectional study in Salvador, Brazil

This study aims to describe the types of intrafamilial violence perpetrated against children according to living conditions, family factors, and child characteristics, and to identify the association between types of intrafamilial violence and asthma symptoms in atopic and non-atopic children. A cross-sectional study was carried out with 1,370 caregivers as part of the Social Changes, Asthma and Allergy in Latin America (SCAALA) study, conducted in 2006 in Brazil. The study population was selected by random sampling. The main outcome measures were atopic and non-atopic asthma. We investigate the association between intrafamilial violence and asthma symptoms in atopic and non-atopic children. A backward multivariate logistic polytomous regression was performed to verify the main association. Nonviolent discipline (NVD) and maltreatment nonviolent discipline (MNVD) were positively associated with non-atopic asthma symptoms (NVD: odds ratio (OR)=1.95/95% confidence interval (CI)=1.17-3.25; MNVD: OR=1.95/95% CI=1.19-3.20). However, for the most severe intrafamilial violence, this association was not found after control of potential confounders. This study demonstrates the effect of types of intrafamilial violence on non-atopic asthma. Intrafamilial violence against children represents one more component in the determination of non-atopic asthma in Latin America.

Risk factors for acute asthma in tropical America: a case-control study in the City of Esmeraldas, Ecuador

BACKGROUND

Despite the high asthma rates described in Latin America, asthma risk factors in poor urban settings are not well established. We investigated risk factors for acute asthma among Ecuadorian children.

METHODS

A matched case-control study was carried out in a public hospital serving a coastal city. Children with acute asthma were age- and sex-matched to non-asthmatics. A questionnaire was administered, and blood, as well as stool, and nasopharyngeal swabs were collected.

RESULTS

Sixty cases and 119 controls aged 5-15 were evaluated. High proportions of cases were atopic with population-attributable fractions for atopy of 68.5% for sIgE and 57.2% for SPT. Acute asthma risk increased with greater titers of mite IgE (3.51-50 kU/l vs. <0.70kU/l - OR 4.56, 95% CI 1.48-14.06, p = 0.008; >50kU/l vs. <0.70kU/l - OR 41.98, 95% CI: 8.97-196.39, p < 0.001). Asthma risk was significantly independently associated with bronchiolitis (adj. OR: 38.9, 95% CI 3.26-465), parental educational level (adj. OR 1.26, 95% CI: 1.08-1.46), and presence of sIgE (adj. OR: 36.7, 95% CI: 4.00-337), while a reduced risk was associated with current contact with pets (adj. OR: 0.07, 95% CI: 0.01-0.56). Rhinovirus infection was more frequent in cases (cases 35.6% vs. controls 7.8%, p = 0.002). None of the cases were on maintenance therapy with inhaled corticosteroids and most relied on emergency department for control.

CONCLUSIONS

A high proportion of children presenting to a public hospital with acute asthma were allergic to mite, particularly at high IgE titer. Poor asthma control resulted in overuse of emergency care.

[Dietary pattern, asthma, and atopic and non-atopic wheezing in children and adolescents: SCAALA study, Salvador, Bahia State, Brazil]

A cross-sectional study was conducted on dietary patterns and their influence on the occurrence of wheezing and atopic and non-atopic asthma in a sample of 1,168 children and adolescents in Salvador, Bahia State, Brazil. Wheezing and asthma symptoms in the previous 12 months were obtained using the ISAAC questionnaire. The presence of aeroallergen-specific IgE was identified. A food frequency questionnaire was used to define dietary patterns. The study applied logistic regression and multinomial polytomous logistic regression. Fish consumption was associated with a 27% reduction in wheezing (95%CI: 0.56-0.94), 37% in asthma (95%CI: 0.47-0.83), 51% in non-atopic asthma (95%CI: 0.31-0.79), and 38% in non-atopic wheezing (95%CI: 0.46-0.83). The highest tertile of dietary patterns reduced wheezing by 27% (95%CI: 0.57-0.95), atopic wheezing by 46% (95%CI: 0.30-0.98), asthma by 36% (95%CI: 0.49-0.83), and atopic asthma by 50% (95%CI: 0.28-0.89). Fish consumption may thus have a protective effect against wheezing and non-atopic asthma and dietary pattern against atopic asthma and wheezing.

Social determinants of childhood asthma symptoms: an ecological study in urban Latin America

Asthma is an important public health problem in urban Latin America. This study aimed to analyze the role of socioeconomic and environmental factors as potential determinants of asthma symptoms prevalence in children from Latin American (LA) urban centers. We selected 31 LA urban centers with complete data, and an ecological analysis was performed. According to our theoretical framework, the explanatory variables were classified in three levels: distal, intermediate, and proximate. The association between variables in the three levels and prevalence of asthma symptoms was examined by bivariate and multivariate linear regression analysis weighed by sample size. In a second stage, we fitted several linear regression models introducing sequentially the variables according to the predefined hierarchy. In the final hierarchical model Gini Index, crowding, sanitation, variation in infant mortality rates and homicide rates, explained great part of the variance in asthma prevalence between centers (R(2) = 75.0 %). We found a strong association between socioeconomic and environmental variables and prevalence of asthma symptoms in LA urban children, and according to our hierarchical framework and the results found we suggest that social inequalities (measured by the Gini Index) is a central determinant to explain high prevalence of asthma in LA.

Mechanisms of obesity in asthma

PURPOSE OF REVIEW

Obesity and asthma are chronic conditions affecting millions of people worldwide. The two conditions also appear to be linked with an increased risk of asthma in people who are obese. The purpose of this review is to describe mechanism(s) that may explain the association between asthma and obesity.

RECENT FINDINGS

Current evidence suggests that the association between asthma and obesity is linked by two major phenotypes and three important pathways of obesity-related asthma: one phenotype with primary (often atopic) asthma that is aggravated by obesity and a second phenotype with late-onset nonatopic asthma, which predominantly affects women and primarily seems to be associated with neutrophilic inflammation. Proposed pathways include the mechanical effects of obesity (fewer deep inspirations leading to increased airway hyperresponsiveness), an inflammatory pathway driven by obesity-related cytokines (adipokines), and finally environment and lifestyle changes that have led to an increasing prevalence of obesity over the past 50 years (including exposures in utero, physical activity, and diet) may also result in asthma in predisposed individuals. How these environmental changes influence the occurrence and expression of asthma may depend on the age of exposure and on interactions with genetic susceptibilities.

SUMMARY

Future research should be directed to shed light on the associations between obesity and asthma phenotypes, modern lifestyles and environmental exposures and genetic susceptibilities.

VIDEO ABSTRACT

http://links.lww.com/COAI/A6.

Risk factors for non-atopic asthma/wheeze in children and adolescents: a systematic review

Background

The study of non-atopic asthma/wheeze in children separately from atopic asthma is relatively recent. Studies have focused on single risk factors and had inconsistent findings.

Objective

To review evidence on factors associated with non-atopic asthma/wheeze in children and adolescents.

Methods

A review of studies of risk factors for non-atopic asthma/wheeze which had a non-asthmatic comparison group, and assessed atopy by skin-prick test or allergen-specific IgE.

Results

Studies of non-atopic asthma/wheeze used a wide diversity of definitions of asthma/wheeze, comparison groups and methods to assess atopy. Among 30 risk factors evaluated in the 43 studies only 3 (family history of asthma/rhinitis/eczema, dampness/mold in the household, and lower respiratory tract infections in childhood) showed consistent associations with non-atopic asthma/wheeze. No or limited period of breastfeeding was less consistently associated with non-atopic asthma/wheeze. The few studies examining the effects of overweight/obesity and psychological/social factors showed consistent associations. We used a novel graphical presentation of different risk factors for non-atopic asthma/wheeze, allowing a more complete perception of the complex pattern of effects.

Conclusions

More research using standardized methodology is needed on the causes of non-atopic asthma.

Asthma in Hispanics. An 8-year update

This review provides an update on asthma in Hispanics, a diverse group tracing their ancestry to countries previously under Spanish rule. A marked variability in the prevalence and morbidity from asthma remains among Hispanic subgroups in the United States and Hispanic America. In the United States, Puerto Ricans and Mexican Americans have high and low burdens of asthma, respectively (the "Hispanic Paradox"). This wide divergence in asthma morbidity among Hispanic subgroups is multifactorial, likely reflecting the effects of known (secondhand tobacco smoke, air pollution, psychosocial stress, obesity, inadequate treatment) and potential (genetic variants, urbanization, vitamin D insufficiency, and eradication of parasitic infections) risk factors. Barriers to adequate asthma management in Hispanics include economic and educational disadvantages, lack of health insurance, and no access to or poor adherence with controller medications such as inhaled corticosteroids. Although considerable progress has been made in our understanding of asthma in Hispanic subgroups, many questions remain. Studies of asthma in Hispanic America should focus on environmental or lifestyle factors that are more relevant to asthma in this region (e.g., urbanization, air pollution, parasitism, and stress). In the United States, research studies should focus on risk factors that are known to or may diverge among Hispanic subgroups, including but not limited to epigenetic variation, prematurity, vitamin D level, diet, and stress. Clinical trials of culturally appropriate interventions that address multiple aspects of asthma management in Hispanic subgroups should be prioritized for funding. Ensuring high-quality healthcare for all remains a pillar of eliminating asthma disparities.

Prevalence of asthma, rhinitis and eczema symptoms in rural and urban school-aged children from Oropeza Province - Bolivia: a cross-sectional study

Background

Asthma and allergies are world-wide common chronic diseases among children and young people. Little information is available about the prevalence of these diseases in rural areas of Latin America. This study assesses the prevalence of symptoms of asthma and allergies among children in urban and rural areas at Oropeza Province in Bolivia.

Methods

The Spanish version of the ISAAC standardized questionnaire and the ISAAC video questionnaire were implemented to 2584 children attending the fifth elementary grade in 36 schools in Oropeza province (response 91%). Lifetime, 12 months and severity prevalence were determined for asthma, rhinitis and eczema symptoms. Odds ratios (OR) with 95% confidence intervals (95% CI) were calculated adjusting for age using generalized linear mixed-effects models.

Results

Median age of children was 11 years, 74.8% attended public schools, and 52.1% were female. While children attending urban schools had lower prevalence of self-reported wheeze in the written questionnaire (adjusted OR 0.6; 95% CI 0.4-1.9), they were more likely than children attending rural schools to report wheeze in the video questionnaire (aOR 2.1; 95% CI 1.0-2.6). They also reported more frequently severe rhinoconjunctivitis (aOR 2.8; 95% CI 1.2-6.6) and severe eczema symptoms (aOR 3.3; 95% CI 1.0-11.0).

Conclusion

Overall in accordance with the hygiene hypothesis, children living in urban areas of Bolivia seem to have a higher prevalence of symptoms of asthma and allergies compared to children living in the country side. In order to develop primary prevention strategies, environmental factors need to be identified in future studies.

Microbial exposure and onset of allergic diseases - potential prevention strategies?

Chronic inflammatory diseases are a major health problem with global dimension. Particularly, the incidence of allergic diseases has been increased tremendously within the last decades. This world-wide trend clearly indicates the demand for new approaches in the investigation of early allergy development. Recent studies underlined the basic postulate of the hygiene hypothesis that early exposure to microbial stimuli plays a crucial role in the prevention of chronic inflammatory conditions in adulthood. There is ample evidence that, both, exogenous microbes and endogenous microbial communities, the human microbiota, shape the developing immune system and might be involved in prevention of pathologic pro-inflammatory trails. According to the Barker hypothesis, epidemiological studies pointed to transmaternal transmission from the mother to the offspring already in prenatal life. Experimental data from murine models support these findings. This state of the art review provides an overview on the current literature and presents new experimental concepts that point out to future application in the prevention of allergic diseases.

Asthma and Microbes: A New Paradigm

Asthma is worldwide at pandemic levels for the past 30 years but is increasing at a greater rate in more affluent societies. It is a heterogeneous disorder caused by interaction between genetic predisposition, atopy, and environmental factors, including allergens, air pollution, and respiratory infections. The pathological aspects and pathophysiological mechanisms are reviewed in this chapter. Allergens or infectious agents may stimulate Th-2 inflammation which causes activation of IL-13, eosinophils, and increase IgE levels, subsequently leading to bronchial smooth muscle hypercontraction. Respiratory viral infections are well-known causes of precipitation of acute asthma exacerbations in 50–60 % of attacks. There is also increasing evidence that bacterial infections, Chlamydia pneumoniae, and Mycoplasma pneumoniae, may contribute to the onset and course of asthma. The two main hypothesis of microbial genesis of asthma that has arisen in the past 20–30 years appears to be incongruous, but are not, are the hygiene hypothesis of asthma, and the virus-related asthma, early onset of viral bronchiolitis in the susceptible hosts being responsible for later development of asthma. The clinical and experimental evidences to support these contentions are reviewed and critiqued.

Food and nutrition insecurity: a marker of vulnerability to asthma symptoms

OBJECTIVE

To evaluate the association between food and nutrition insecurity and asthma in children from Latin America.

DESIGN

Cross-sectional study.

SETTING

São Francisco do Conde, Bahia, north-eastern Brazil.

SUBJECTS

The study included 1307 children aged 6-12 years from public elementary schools. Asthma symptoms were collected using a questionnaire that was translated and adapted from the International Study of Asthma and Allergies in Childhood, phase III. The diagnosis of asthma was determined based on reports of wheezing in the previous 12 months. The Brazilian Food Insecurity Scale was used to identify food insecurity. We also obtained demographic, socio-economic and anthropometric information for each participant. We used multivariate logistic regression analyses to assess the associations of interest.

RESULTS

Of the children surveyed, 10·4% had a history of wheezing and 64·5% had some degree of food and nutrition insecurity. We found a positive dose-response relationship and statistically significant associations of asthma with moderate (OR = 1·71, 95% CI 1·01, 2·89) and severe (OR = 2·51, 95% CI 1·28, 4·93) food and nutrition insecurity.

CONCLUSIONS

The results show that moderate and severe food and nutrition insecurity are markers of vulnerability to wheezing. It is important to note that the results of studies in this field have potential implications for social policies that promote food security. Further studies to identify the mechanisms involved in the relationship between food and nutrition insecurity and asthma are needed.

Association between environmental factors and current asthma, rhinoconjunctivitis and eczema symptoms in school-aged children from Oropeza Province--Bolivia: a cross-sectional study

BACKGROUND

In recent years, the prevalence of asthma, rhinoconjunctivitis and eczema symptoms in childhood has considerably increased in developing countries including Bolivia, possibly due to changes in lifestyle, environmental and domestic factors. This study aimed to assess the association between environmental factors and asthma, rhinoconjuctivitis and eczema symptoms in school-aged children from Oropeza Province in Chuquisaca, Bolivia.

METHODS

A cross-sectional study was performed in 2340 children attending the fifth grade in 36 randomly selected elementary schools in Oropeza province. The prevalence of symptoms was determined using the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaire. Environmental factors were assessed by the ISAAC environmental questionnaire including questions related to exposure to pets, farm animals, indoor and outdoor pollution, presence of disease vectors at home and precarious household conditions. Generalized linear mixed-effects models were adjusted for age, sex and place of living.

RESULTS

Thirty seven percent of children reported that at least one of their parents smoked at home. Wood or coal was used as cooking fuel in 19% of the homes and 29% reported intense truck traffic on the street where they lived. With respect to hygiene conditions, 86% reported exposure to dogs, 59% exposure to cats and 36% regular contact to farm animals. More than one precarious household condition was reported by 8% of children. In the adjusted model exposure to dog (adjusted OR 1.4; CI 95% 1.0-1.9), cat (1.2; 1.0-1.5), farm animals (1.5; 1.2-1.8); intense truck traffic (1.3; 1.0-1.6), parents smoking at home (1.2; 1.0-1.5), presence of disease vectors at home (fourth quartile vs. first quartile: 1.6; 1.2-2.3) and two or more precarious household conditions (1.5; 1.0-2.2) were significantly associated with rhinoconjunctivitis symptoms. The associations were similar for asthma and eczema symptoms; however it did not reach the level of statistical significance for all items.

CONCLUSION

Our results support previous findings reported for poor communities especially in Latin America, showing that lower hygiene conditions did not have protective effect against asthma and rhinoconjunctivitis and eczema symptoms.

Environmental conditions, immunologic phenotypes, atopy, and asthma: new evidence of how the hygiene hypothesis operates in Latin America

BACKGROUND

It has been proposed that improved hygiene and reduced experience of infections in childhood influences the development of allergic diseases. The mechanisms by which the hygiene operates are not well established but are underpinned by two apparently incompatible immunologic paradigms, the balance of TH1 versus TH2 cytokines and IL-10-mediated regulation of TH2 cytokines.

OBJECTIVE

This study defined immunologic phenotypes with the use of latent class analysis and investigated their associations with environmental factors, markers of allergy and asthma, in a Latin American population.

METHODS

We studied 1127 children living in urban Brazil. Data on wheeze and environmental exposures were collected with standardized questionnaires. Atopy was measured by specific IgE in serum and skin prick test reactivity to aeroallergens. Cytokines were measured in culture after the stimulation of peripheral blood leukocytes with mitogen. Infections with pathogens were assessed by serology and stool examinations. Children were classified as having high or low burden of infection. Latent class analysis was used to identify immune phenotypes on the basis of cytokine production. Logistic regression was used to evaluate the adjusted effects of environment and burden of infection on the immunologic phenotypes and the effect of the phenotypes on atopy and asthma.

RESULTS

Three phenotypes were identified, labeled underresponsive, intermediate, and responsive. Children of more educated mothers, living in improved environmental conditions, and with a low burden of infection were significantly more likely to have the responsive phenotype. The responsive phenotype was significantly associated with an increased prevalence of atopy but not asthma.

CONCLUSION

Our findings contribute to a better understanding of the immune mechanisms by which the hygiene hypothesis operates in urban Latin America.