Is childhood wheeze and asthma in Latin America associated with poor hygiene and infection? A systematic review

Global Burden of Asthma, and Its Impact on Specific Subgroups: Nasal Polyps, Allergic Rhinitis, Severe Asthma, Eosinophilic Asthma

Background

The complex nature of asthma has resulted in a poor understanding of its epidemiology, particularly in low-and middle-income countries (LMIC). Clinical subgroups, such as patients with severe asthma, eosinophilic asthma, allergic rhinitis, or nasal polyps, experience additional barriers to care.

Methods

Prevalence estimates for asthma and key clinical subgroups were extracted from the Global Burden of Diseases, Injuries, and Risk Factors Study 2019 and from a targeted literature review conducted through PubMed in October of 2021. National estimates were calculated and the roles of potential explanatory factors were explored through qualitative analysis.

Results

In total, 162 publications from 69 countries were included. Across continents, asthma prevalence values ranged from 3.44% (Asia), 3.67% (Africa), 4.90% (South America), 5.69% (Europe), 8.29% (North America), to 8.33% (Oceania). Globally, of those with asthma, 26.70% had severe asthma, 30.99% had eosinophilic asthma, 48.95% had allergic rhinitis, and 7.0% to 25.40% had nasal polyps. Countries with higher air quality, income status, and healthcare access and quality reported a higher asthma prevalence.

Conclusion

Asthma prevalence values were low in LMICs, potentially indicating health system deficiencies resulting in low diagnosis and reporting. The prevalence of eosinophilic asthma and severe asthma phenotypes was high in many countries, although the prevalence estimates of all asthma subgroups were quite variable.

Effect of pharmacists' interventions on health outcomes of children with asthma: A systematic review

METHODS

A literature search was performed in January 23, 2018 at the Embase, LILACS, OpenThesis, PubMed, Cochrane Library, and Web of Science databases through January 23, 2018, using keywords related to "asthma," "pharmacist," and "children." This systematic review followed the methodologic standards recommended by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. We included intervention studies on the effect of pharmacists' interventions on pediatric patients with asthma, performed in hospital or ambulatory care settings, with presenting process and outcome indicators as a result of pharmacists' interventions. The methodologic quality of the included studies was assessed independently by 2 researchers. The Cohen kappa index was used to measure the degree of agreement between the 2 investigators.

RESULTS

The search yielded 3671 records, of which 5 were included in this review. Most of these studies were conducted in the United States (n = 2) and in outpatient clinics (n = 4). All studies described components of pharmacists' interventions. The most reported category concerning pharmacists' work process was the initial assessment of patients' conditions, with the assessment of outcomes (at baseline and follow-up) as the only category present in all studies. The most assessed outcomes at baseline were asthma control, emergency department visits, medication use and technique, and adherence to asthma therapy. At follow-up, emergency department visits were the most evaluated outcome (n = 2), and no study assessed economic outcomes. The average consultation time ranged from 20 to 45 minutes, and the number of encounters ranged from 2 to 3.

CONCLUSION

This study highlighted the limited number of studies, most with low quality, on the impact of the pharmacist on pediatric asthma. The most assessed outcome was the number of emergency department visits, with positive results after interventions. Heterogeneity regarding assessed outcomes and work processes was noted, which limited comparison of the results and interventions.

Association of Cow's Milk Protein Allergy Prevalence With Socioeconomic Status in a Cohort of Chilean Infants

OBJECTIVES

The aim of the study was to compare the cow's milk protein allergy (CMPA) prevalence in 2 cohorts of children from different socioeconomic strata.

METHODS

Prospective birth cohort that included patients from 2 hospitals providing care for a low- and high-income population, respectively. Healthy newborns ≥34 gestational weeks were recruited and followed up to 12 months by a monthly telephone survey. If ≥2 predefined symptoms/signs suggestive of CMPA were detected, the patient was evaluated by a pediatric gastroenterologist. Diagnosis was confirmed by exclusion diet followed by open oral food challenge.

RESULTS

Overall the prevalence of CMPA was 5.2%, with a 6 times higher prevalence in the high income cohort (9.2%) compared with the low-income group (1.5%; relative risk 6.2; 95% confidence interval 1.8-20.7; P = 0.0005). All the cases were non-immunoglobulin E-mediated with predominantly gastrointestinal symptoms. High-income cohort did have higher frequency of C-section, mother's previous chronic disease, mother's history of atopy/food allergy, older age, and higher educational level of parents. Parent smoking and presence of pets at home were more frequent in the low-income cohort. Multiple logistic regression showed that the high-income cohort did have older age and higher educational level of both parents.

CONCLUSION

In these cohorts the prevalence of CMPA was higher than reported previously in other developing countries and significantly higher in the high-income group. Our findings were associated with sociodemographic characteristics of the parents.

Classification of Wheezing Children in Rural Bangladesh by Intensity of Ascaris Infection, Total and Specific IgE Levels, History of Pneumonia, and Other Risk Factors

Ascaris lumbricoides is the most common soil-transmitted helminth and infects 447 million people in impoverished areas worldwide. It causes serious morbidity including wheezing and influences various aspects of human immunity, such as type 2 innate lymphoid cells, regulatory T cell function, and acquired immunity. Thus, it is crucial to elucidate its influence on human immunity. We aimed to classify wheezing children based on their Ascaris infection intensity and other risk factors using hierarchical cluster analysis to determine the mechanisms of and the degree to which Ascaris contributes to childhood wheezing in rural Bangladesh. We analyzed relevant data collected in 2001. The participants included 219 5-year-old wheezing children who were randomly selected from 1705 children living in the Matlab Health and Demographic Surveillance area of the International Centre for Diarrhoeal Disease Research, Bangladesh. Hierarchical cluster analysis was conducted using variables of history of pneumonia, total and specific immunoglobulin E levels, Ascaris infection intensity, and parental asthma. Three distinct wheezing groups were identified. Children in Cluster 1 (n = 50) had the highest titers of the total, anti-Ascaris, anti-Dermatophagoides pteronyssinus, and anticockroach IgEs and experienced the fewest episodes of pneumonia. Cluster 2 (n = 114), the largest group, experienced few episodes of pneumonia and had the lowest titers of the total, anti-Ascaris, anti-Dp, and anticockroach IgEs. Cluster 3 (n = 32) consisted of participants with the most episodes of pneumonia and lower titers of the total and specific IgEs. The extremely high prevalence of Ascaris infection found in Clusters 1-3 was 78%, 77%, and 72%, respectively. Childhood wheezing in rural Bangladesh could be divided into three groups, with 26% of wheezing attributable to anti-Ascaris IgE and 16% to history of pneumonia during early childhood, and 58% might have been due to Ascaris infection without elevated anti-Ascaris IgE.

Concurrent decreases in the prevalence of wheezing and Ascaris infection among 5-year-old children in rural Bangladesh and their regulatory T cell immunity after the implementation of a national deworming program

INTRODUCTION

Epidemiological research on the prevalence of asthma and helminthic infections in various countries has led to the hypothesis that helminthic infections protect against asthma by suppressing the host's immune response. This study was conducted to elucidate whether decreased Ascaris infection following a national deworming program was associated with increased recurrent wheezing among rural Bangladeshi children and to test their anti-inflammatory immunity.

METHODS

This nested case-control study was conducted from December 2015 to October 2016 in the rural service area of the International Centre for Diarrhoeal Disease Research, Bangladesh. Of the 1800 5-year old children randomly selected for the study, informed consent was obtained from the guardians of 1658 children. Data were collected using a semistructured questionnaire adopted from the International Study of Asthma and Allergies in Childhood and blood samples for the analysis of regulatory T (Treg) cell immune responses and the balance between Th1 and Th2 immunity in Ascaris infections.

RESULTS

A total of 145 children were found to have wheezing, yielding a prevalence rate of 8.7%, which was significantly lower than the rate found in 2001 (16.2%, P < .001); Ascaris infection also decreased from 2001 to 2016. The 127 wheezing children who agreed to participate further were compared to 114 randomly selected never-wheezing children. Wheezing had a significant positive association with antibiotic use, history of pneumonia, parents' history of asthma, and Ascaris infection; children with Ascaris infection were twice as likely to have wheezing (adjusted odds ratio = 2.31, P = .053). Flow cytometry found no significant differences in the rates of Th1, Th2, and CD4 + CD25 + CD127low cells by the wheezing group.

CONCLUSIONS

Ascaris infection had a positive rather than a negative association with wheezing and the rates of wheezing and Ascaris infections both decreased from 2001 to 2016. These findings undermines the hypothesis that such infections provide protection against asthma.