Asthma in rural Bangladeshi children

Self-reported prevalence of asthma and its associated factors among adult rural population in Bangladesh: a cross-sectional study using WHO PEN protocol

OBJECTIVE

For over a decade, the prevalence of asthma remained unchanged at around 7% in Bangladesh. Although asthma causes significant morbidity among both children and adults, updates on epidemiological data are limited on the prevalence in Bangladesh. This study attempted to determine the prevalence of asthma, and its modifiable and non-modifiable lifestyle predictors in a rural population of Bangladesh.

METHOD

This study was part of a cross-sectional study that applied the WHO Package of Essential Noncommunicable Disease Interventions via census in a rural area of Bangladesh, where self-reported data on asthma were recorded. Data on anthropometric measurement, sociodemographic characteristics and behavioural risk factors were collected following the standard protocol described in the WHO STEP-wise approach to surveillance (STEPS) questionnaire. Analysis included descriptive statistics to assess the prevalence of asthma and its risk factors, and binary logistic regression to determine contributing factors.

RESULT

The overall prevalence of asthma was 4.2%. Asthma was predominant among people above 60 years (8.4%). Higher asthma was noted among males (4.6%), self-employed (5.1%), with a family history of asthma (9.1%), with comorbidities besides asthma (7.8%) and underweight (6.0%) compared with their counterparts. The OR of having asthma was 1.89, 1.93, 1.32, 1.50, 2.60, 0.67, 0.67 and 0.78 if a respondent was 45 years old or more, married, underweight, ever smoker, with a family history of asthma, housewife, employed and consumed red meat, respectively, while considering all other variables constant, compared with their counterparts.

CONCLUSION

The study emphasised asthma to be a public health concern in Bangladesh, although it seems to have decreased over the last decade. Among others, red meat intake and nutritional status were strongly associated with asthma, and the linkage among these is still a grey area that needs further exploration.

Pollen allergy: Developing multi-sectorial strategies for its prevention and control in lower and middle-income countries

Pollen allergy is considered a major public health problem that causes morbidity and subsequently affects a patient's quality of life. Pollen due to their large size cannot enter the thoracic regions of the respiratory tract but can affect the nasopharyngeal mucous membrane. At the same time, the submicronic-pollen particles can act as respirable particles reaching deeper into the upper airways leading to exacerbation of asthma, chronic obstructive pulmonary disease (COPD) and other allergic reactions. Based on the existing literature, expanding evidence shows that climate change and air pollutants could affect the pollen number, morphology, season, allergen content, and distribution pattern. Hence, this will influence the prevalence and occurrence of allergies linked to pollen exposure. Being a part of biogenic pollutants, pollen allergens are not expected to diminish in the foreseeable future. Therefore, it is imperative that steps need to be strengthened to improve and optimize preventive/adaptive strategies. This paper aims to review the major causes of widespread allergy, identify the major gaps, and suggest key preventive/adaptive measures to address the onset and exacerbation of pollen-related allergic diseases with a major focus on lower and middle-income countries. The study also discusses how-to implement the prevention and control measures at the individual, health care communities and organizations, Local Governments, National/International Governments levels to decrease the risk of illnesses associated with pollen allergy.

Risk factors of asthma in the Asian population: a systematic review and meta-analysis

Background and objective

An increasing trend of asthma prevalence was observed in Asia; however, contributions of environmental and host-related risk factors to the development of this disease remain uncertain. This study aimed to perform a systematic review and meta-analysis for asthma-associated risk factors reported in Asia.

Methods

We systematically searched three public databases (Web of Science, PubMed, and Scopus) in Feb 2021. We only included articles that reported environmental and host-related risk factors associated with asthma in the Asian population. Random-effect meta-analyses were conducted for frequently reported asthma-associated risk factors to provide an overall risk estimate of asthma development.

Results

Of 4030 records obtained from public databases, 289 articles were selected for review. The most frequently reported asthma-associated risk factor was the family history of allergy-related conditions. The random-effect asthma risk estimates (pooled odds ratio, OR) were 4.66 (95% confidence interval (CI): 3.73–5.82) for the family history of asthma, 3.50 (95% CI: 2.62–4.67) for the family history of atopy, 3.57 (95% CI: 3.03–4.22) for the family history of any allergic diseases, 1.96 (95% CI: 1.47–2.61) for the family history of allergic rhinitis, and 2.75 (95% CI: 1.12–6.76) for the family history of atopic dermatitis. For housing-related factors, including the presence of mold, mold spots, mold odor, cockroach, water damage, and incense burning, the random-effect pooled OR ranged from 1.43 to 1.73. Other risk factors with significant pooled OR for asthma development included male gender (1.30, 95% CI: 1.23–1.38), cigarette smoke exposure (1.44, 95% CI: 1.30–1.60), cigarette smoking (1.66, 95% CI: 1.44–1.90), body mass index (BMI)–related parameters (pooled OR ranged from 1.06 to 2.02), various types of air pollution (NO₂, PM10, and O₃; pooled OR ranged from 1.03 to 1.22), and pre- and perinatal factors (low birth weight, preterm birth, and cesarean section; pooled OR ranged from 1.14 to 1.32).

Conclusions

The family history of asthma was the most frequently reported risk factor for asthma development in Asia with the highest risk estimate for asthma development. This suggests a major role of the genetic component in asthma pathogenesis. Further study on asthma genetics is required to improve the current understanding of asthma etiology.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40101-021-00273-x.

Operational definitions of paediatric asthma used in epidemiological studies: A systematic review

Background

Researchers use different definitions to identify children with asthma in epidemiological surveys. We conducted a systematic review to describe the definitions used in epidemiologic studies for wheeze and asthma in the paediatric population, aimed to inform the development of a uniform definition of paediatric asthma for future epidemiological research.

Methods

We systematically searched terms to identify asthma and/or wheeze among children aged <13 years and published between 1995-2020 across seven databases (MEDLINE, EMBASE, PsycINFO, Global Health, AMED, LILACS and CINAHL). PRISMA guidelines were followed for this review.

Results

We extracted a total of 11 886 records, where 190 met our eligibility criteria and included in the analysis. Among the included studies, 62.1% (n = 118/190) used the International Study of Asthma and Allergies in Childhood (ISAAC) questionnaires, predominantly in developing countries (80%, n = 64/80). ‘Wheeze’ was reported in five categories, subdivided by 14 different definitions. “Current wheeze”, defined as caregivers report of wheezing sounds from the chest of the child in the past 12 months and “Wheeze ever”, defined as caregivers’ report of wheezing or whistling in the chest of the child at any previous time, were the most common wheeze category reported in 129 and 95 studies, respectively. Asthma was reported in nine categories using 53 definitions. The most common asthma category was “Asthma ever”, which was reported in 89 studies, based on caregiver statement that the child had asthma in the past.

Conclusion

Definitions of wheeze and asthma for children used in surveys are primarily based on parent-reported clinical features. Studies from developing countries more frequently used the ISAAC definitions to report childhood asthma and wheeze compared to the studies from developed counties. The use of a uniform asthma definition will aid the interpretation of research findings globally.

A systematic review of the evidence of outdoor air pollution on asthma hospital visits in children and adolescents in South Asia - a call for data

Background: Outdoor air pollution and childhood asthma are increasing problems in South Asian countries. However, little is known about the associations between levels of air pollution and severe childhood asthma requiring hospital treatment in these regions. Methods: We undertook a systematic review to assess the evidence between outdoor air pollution exposure and childhood and adolescent asthma hospitalization in South Asia. MEDLINE, Web of Science, Google Scholar, CINAHL, Embase, Scopus, ProQuest Central databases were searched for peer-reviewed papers, and examination of reference lists was conducted for additional studies. We identified all the literature published in English up to January 2021 for the study population comprised of children aged less than 19 years. The search strategy was designed to identify all the studies and screen them as per the inclusion criteria. The method of qualitative synthesis using the standard tool determined the comprehensiveness of the assessment of bias. Results: Of the original 367 studies screened three studies were ultimately included from India, Pakistan and Sri Lanka and a narrative synthesis was conducted. Although studies reported adverse effects of outdoor pollution on asthma hospitalizations, limitations in exposure assessments, varying definitions of asthma hospitalizations and limited data analysis were identified. Conclusions: There is currently limited evidence that can provide meaningful risk estimates of the impact of outdoor air pollution on asthma hospitalizations during childhood and adolescence. Studies with comparable outcome definitions, appropriate exposure assessments and study designs are needed to inform future public and environmental health policy. PROSPERO registration: CRD42020156714 (28/04/2020).

Incidence and timing of offspring asthma, wheeze, allergic rhinitis, atopic dermatitis, and food allergy and association with maternal history of asthma and allergic rhinitis

Background

Studying the developmental precursors of allergy may help explain the mechanisms (or etiology) of allergic disease. We studied childhood respiratory and allergic diseases in a pre-birth cohort from the United States.

Objective

We assessed the associations between maternal history of asthma and the development of respiratory and allergic diseases in offspring. We also assessed associations with maternal history of allergic rhinitis.

Methods

Maternal history of asthma and allergic rhinitis was self-reported during early pregnancy. Offspring respiratory and allergy information was obtained from electronic medical records. Adjusted Cox proportional hazard models assessed the associations between maternal history of asthma and development of respiratory and allergic diseases in the offspring up to 8 years. A similar approach was used for maternal history of allergic rhinitis.

Results

Children born to women with a history of asthma had a 77% greater risk of developing asthma, a 45% greater risk of atopic dermatitis/eczema, and a 65% greater risk of wheeze (all p < 0.01), but no significantly increased risk of allergic rhinitis or food allergies, compared to children born to women with no history of asthma. Maternal history of allergic rhinitis was not associated with any child allergy outcome, and maternal history of both asthma and allergic rhinitis was associated with child atopic dermatitis/eczema only.

Conclusions

Maternal history of asthma was significantly associated with offspring respiratory and allergic diagnoses. The association between maternal history of asthma and offspring asthma and atopic dermatitis is a novel finding. Our findings may guide physicians who counsel families with a history of maternal asthma and allergic rhinitis about their child's risk of developing respiratory and allergic diseases.

Impact of Haemophilus influenzae type b combination vaccination on asthma symptoms and pneumonia in 5-year-old children in rural Bangladesh: a longitudinal study and comparison with a previous cross-sectional study

BACKGROUND

Although the prevalence of bronchial asthma has been increasing worldwide since the 1970's, the prevalence among 5-year-old children was significantly lower in 2016 than in 2001 in rural Bangladesh. We aimed to determine whether the Haemophilus influenzae type b (Hib) combination vaccination (without booster) started in 2009 contributed to this decrease.

METHODS

A case-control study was conducted among 1658 randomly selected 5-year-old children from Matlab, Bangladesh. Data on wheezing were collected using the International Study of Asthma and Allergies in Childhood questionnaire. The vaccination data were collected from the records of the Matlab Health and Demographic Surveillance System, while data on pneumonia were obtained from the clinical records of Matlab Hospital. Adjusted odds ratios (aORs) were calculated for the risk for wheezing. The reduction rate was calculated to determine the impact of the vaccination on pneumonia history between the present study and our previous study conducted in 2001 by using the following formula: (percentage of pneumonia cases in 2001 - percentage of pneumonia cases in 2016)/(percentage of pneumonia cases in 2001) times 100 (%).

RESULTS

Hib combination vaccination was a protecting factor against wheezing (aOR: 0.50; p = 0.010), while pneumonia at 1, 2, 3-4 years of age were risk factors for wheezing (aOR: 2.86, 3.19, 2.86; p = 0.046, 0.030, 0.030, respectively). The history of pneumonia was significantly lower in the 2016 study participants than those in 2001 both in the overall cohort and the wheezing group (paired t-test: p = 0.012, p < 0.001, respectively). Whereas the history of pneumonia decreased when the children grew older in the 2001 overall cohort, it peaked at the age of 2 years in 2016 wheezing group. The reduction rate decreased when children grew older in both the overall cohort and the wheezing group, however, it decreased faster in the wheezing group.

CONCLUSIONS

Hib combination vaccination was a protective factor against wheezing in 0-year-old children. However, the effects of vaccination might have attenuated at the ages of 1-4 years, because no booster dose was administered. The addition of a booster dose might further decrease the prevalence of asthma and wheezing.

What Can Parasites Tell Us About the Pathogenesis and Treatment of Asthma and Allergic Diseases

The same mechanisms that enable host defense against helminths also drive allergic inflammation. This suggests that pathomechanisms of allergic diseases represent evolutionary old responses against helminth parasites and that studying antihelminth immunity may provide insights into pathomechanisms of asthma. However, helminths have developed an intricate array of immunoregulatory mechanisms to modulate type 2 immune mechanisms. This has led to the hypothesis that the lack of helminth infection may contribute to the rise in allergic sensitization in modern societies. Indeed, the anti-inflammatory potential of helminth (worm) parasites and their products in allergy and asthma has been recognized for decades. As helminth infections bring about multiple undesired effects including an increased susceptibility to other infections, intended helminth infection is not a feasible approach to broadly prevent or treat allergic asthma. Thus, the development of new helminth-based biopharmaceutics may represent a safer approach of harnessing type 2–suppressive effects of helminths. However, progress regarding the mechanisms and molecules that are employed by helminths to modulate allergic inflammation has been relatively recent. The scavenging of alarmins and the modulation of lipid mediator pathways and macrophage function by helminth proteins have been identified as important immunoregulatory mechanisms targeting innate immunity in asthma and allergy. In addition, by regulating the activation of dendritic cells and by promoting regulatory T-cell responses, helminth proteins can counterregulate the adaptive T helper 2 cell response that drives allergic inflammation. Despite these insights, important open questions remain to be addressed before helminth molecules can be used for the prevention and treatment of asthma and other allergic diseases.

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.

Burden of serious fungal infections in Bangladesh

In Bangladesh there are several published papers on superficial mycoses. Deep mycoses are also recognized as an important emerging problem. Here, we estimate the annual incidence and prevalence of serious fungal infections in Bangladesh. Demographic data were obtained from world population reports and the data on TB and HIV extracted from the online publications on tuberculosis in Bangladesh and Asia Pacific research statistical data information resources AIDS Data HUB. All the published papers on fungal infections in Bangladesh were identified through extensive search of literature. We estimated the number of affected people from populations at risk and local epidemiological data. Bangladesh has a population of ∼162.6 million, 31% children and only 6% over the age of 60 years. The pulmonary TB caseload reported in 2014 was 119,520, and we estimate a prevalence of 30,178 people with chronic pulmonary aspergillosis, 80% attributable to TB. An anticipated 90,262 and 119,146 patients have allergic bronchopulmonary aspergillosis or severe asthma with fungal sensitization. Only 8,000 people are estimated to be HIV-infected, of whom 2900 are not on ART with a CD4 count <350 μL, Pneumocystis pneumonia and cryptococcal meningitis being rare. Superficial mycoses are very common with Trichophyton rubrum as the predominant etiological agent (80.6%). Numerous cases of mycotic keratitis have been reported from several parts of Bangladesh. Candida bloodstream infection was estimated based on a 5 per 100,000 rate (8100 cases) and invasive aspergillosis based primarily on leukemia and COPD rates, at 5166 cases. Histoplasmosis was documented in 16 cases mostly with disseminated disease and presumed in 21 with HIV infection. This study constitutes the first attempt to estimate the burden of several types of serious fungal infections in Bangladesh.

Anti-Ascaris immunoglobulin E associated with bronchial hyper-reactivity in 9-year-old rural Bangladeshi children

BACKGROUND

Studies have addressed the immunomodulatory effects of helminths and their protective effects upon asthma. However, anti-Ascaris IgE has been reported to be associated with an increased risk of asthma symptoms. We examined the association between serum levels of anti-Ascaris IgE and bronchial hyper-responsiveness (BHR) in children living in rural Bangladesh.

METHODS

Serum anti-Ascaris IgE level was measured and the BHR test done in 158 children aged 9 years selected randomly from a general population of 1705 in the Matlab Health and Demographic Surveillance Area of the International Centre for Diarrhoeal Disease Research, Bangladesh. We investigated wheezing symptoms using a questionnaire from the International Study of Asthma and Allergies in Childhood. BHR tests were successfully done on 152 children (108 'current wheezers'; 44 'never-wheezers'). We examined the association between anti-Ascaris IgE level and wheezing and BHR using multiple logistic regression analyses.

RESULTS

Of 108 current-wheezers, 59 were BHR-positive; of 44 never-wheezers, 32 were BHR-negative. Mean anti-Ascaris IgE levels were significantly higher (12.51 UA/ml; 95% confidence interval (CI), 9.21-17.00) in children with current wheezing with BHR-positive than in those of never-wheezers with BHR-negative (3.89; 2.65-5.70; t test, p < 0.001). A BHR-positive test was independently associated with anti-Ascaris IgE levels with an odds ratio (OR) = 7.30 [95% CI, 2.28-23.33], p = 0.001 when adjusted for total IgE, anti-Dermatophagoides pteronyssinus IgE, pneumonia history, parental asthma, Trichuris infection, forced expiratory volume in one second, eosinophilic leukocyte count, and sex.

CONCLUSIONS

Anti-Ascaris IgE level is associated with an increased risk of BHR among 9-year-old rural Bangladeshi children.

Burden of asthma among children in a developing megacity: childhood asthma study, Pakistan

OBJECTIVES

Global burden of childhood asthma has increased in the past few decades, particularly in low-income countries. In Pakistan, there is a lack of community-based epidemiological studies estimating the burden of asthma among children. This study determined the prevalence and predictors of asthma among children 3-17 years of age in Karachi, Pakistan.

METHODS

A two-stage community-based representative cross-sectional survey was conducted in Karachi from March 2012 to April 2013 comprising 1046 children aged 3-17 years. Of 7500 clusters, 80 were randomly selected, and of these, 15 children per cluster were enrolled randomly. A translated and pre-tested version of International Study of Asthma and Allergies in Children questionnaire was administered.

RESULTS

The overall prevalence of asthma among study participants was 10.2% (95% CI: 8.4-12.0). Asthma was more likely to occur among boys (adj. OR: 2.5, 95% CI: 1.6-4.0), children in the younger age group (3-7 years) (adj. OR: 2.9, 95% CI: 1.7-4.8), those living in households with ill-ventilated kitchens (adj. OR: 1.8, 95% CI: 1.1-3.1), having family history of asthma (adj. OR: 2.3, 95% CI: 1.3-3.9) and those of the Sindhi ethnicity (adj. OR: 2.2, 95% CI: 1.1-4.4).

CONCLUSION

This study is the first robust evidence regarding asthma among children in Pakistan, reporting a high burden in this group. Family history, male gender, Sindhi ethnicity and ill-ventilated kitchen were identified as important predictors of asthma. Targeted preventive measures and intervention studies are required to better understand and reduce the burden of asthma among children in Pakistan.

Nutritional status and childhood wheezing in rural Bangladesh

OBJECTIVE

To investigate the association between current childhood nutritional status and current wheezing among pre-school children in rural Bangladesh.

DESIGN

Cross-sectional study.

SETTING

Matlab region, rural Bangladesh.

SUBJECTS

Children (n 912) aged 4·5 years. Anthropometric measurements of the mothers and their children were taken during a 1-year period from December 2007 to November 2008. Current wheezing was identified using the International Study of Asthma and Allergies in Childhood questionnaire. Serum total IgE was measured by human IgE quantitative ELISA. IgE specific antibody to dust mites (Dermatophagoides pteronyssinus) was measured by the CAP-FEIA system (Phadia AB, Uppsala, Sweden).

RESULTS

Wheezing at 4·5 years old was significantly associated with stunting (OR = 1·58; 95 % CI 1·13, 2·22) and underweight (OR = 1·39; 95 % CI 1·00, 1·94). The association with stunting remained significant after adjustment for sex, birth weight, birth length, gestational age at birth, mother's parity, maternal BMI, family history of asthma, socio-economic status, season of birth and intervention trial arm (OR = 1·74; 95 % CI 1·19, 2·56).

CONCLUSIONS

Stunting was a significant risk factor for wheezing among rural Bangladeshi children. Further studies will be required to confirm the relationship between nutritional status and allergic illnesses in developing countries.

Ascaris lumbricoids Infection as a Risk Factor for Asthma and Atopy in Rural Bangladeshi Children

Controversy persists as to whether helminth infections cause or protect against asthma and atopy. The aim of this study was to investigate the effects of helminth infection on asthma and atopy among Bangladeshi children. A total of 912 children aged 4.5 years (mean = 54.4, range = 53.5–60.8 months) participated in a cross-sectional study nested into a randomized controlled trial in Bangladesh. Ever-asthma, ever-wheezing and current wheezing were identified using the International Study of Asthma and Allergies in Childhood questionnaire. Current helminth infection was defined by the presence of helminth eggs in stools, measured by routine microscopic examination. Repeated Ascaris infection was defined by the presence of anti-Ascaris IgE ≥ 0.70 UA/ml in serum measured by the CAP-FEIA method. Atopy was defined by specific IgE to house dust mite (anti-DP IgE) ≥ 0.70 UA/ml measured by the CAP-FEIA method and/or positive skin prick test (≥ 5 mm). Anti-Ascaris IgE was significantly associated with ever asthma (odds ratio (OR) = 1.86, 95% CI: 1.14–3.04, highest vs. lowest quartile; P for trend 0.016). Anti-Ascaris IgE was also significantly associated with positive anti-DP IgE (OR = 9.89, 95% CI: 6.52–15.00, highest vs. lowest; P for trend < 0.001) and positive skin prick test (OR = 1.69, 95% CI: 1.01–2.81, highest vs. lowest, P for trend 0.076). These findings suggest that repeated Ascaris infection is a risk factor for asthma and atopy in rural Bangladeshi children. Further analysis is required to examine the mechanism of developing asthma and atopy in relation to helminth infection.

Sources and prevalence of self-reported asthma diagnoses in adults in urban and rural settings of Bangladesh

This study provides data on the sources of asthma diagnoses in the adult Bangladeshi population in urban and rural settings. The paper also reports the prevalence of self-reported asthma diagnoses and associated socio-demographic factors. A cross-sectional study was conducted in three communities: two rural settings and one urban setting, with a total sample size of 32,665 subjects. Pre-existing surveillance data provided individual socio-demographic factors. Provider categories were based on previous research describing provider plurality in Bangladesh. Descriptive statistics, univariate regression and multivariate regression analyses were performed. Bachelor of Medicine, Bachelor of Surgery (MBBS) generalists provided the largest proportion of diagnoses in both urban (54.6%) and rural (42.4%) sites. The largest proportion of non-MBBS-trained healthcare workers providing diagnoses of asthma was spiritual healers (13.3%) in the urban settings and village doctors (42.4%) in rural settings. The overall prevalence of self-reported asthma diagnoses was 5.0% in the urban population and 3.5% in the rural population. The results highlight the importance of non-MBBS doctors in serving the healthcare needs of the Bangladeshi population. This study reveals a higher prevalence of self-reported asthma diagnoses in the urban setting than in rural ones, which is consistent with international literature on the topic.

Childhood asthma in low income countries: an invisible killer?

Bacterial pneumonia has hitherto been considered the key cause of the high respiratory morbidity and mortality in children under five years of age (under-5s) in low-income countries, while asthma has not been stated as a significant reason. This paper explores the definitions and concepts of pneumonia and asthma/wheezing/bronchiolitis and examines whether asthma in under-5s may be confused with pneumonia. Over-diagnosing of bacterial pneumonia can be suspected from the limited association between clinical pneumonia and confirmatory test results such as chest x-ray and microbiological findings and poor treatment results using antibiotics. Moreover, children diagnosed with recurrent pneumonia in infancy were often later diagnosed with asthma. Recent studies showed a 10-15% prevalence of preschool asthma in low-income countries, although under-5s with long-term cough and difficulty breathing remain undiagnosed. New studies demonstrate that approximately 50% of acutely admitted under-5s diagnosed with pneumonia according to Integrated Management of Childhood Illnesses could be re-diagnosed with asthma or wheezing when using re-defined diagnostic criteria and treatment. It is hypothesised that untreated asthma may contribute to respiratory mortality since respiratory syncytial virus (RSV) is an important cause of respiratory death in childhood, and asthma in under-5s is often exacerbated by viral infections, including RSV. Furthermore, acute respiratory treatment failures were predominantly seen in under-5s without fever, which suggests the diagnosis of asthma/wheezing rather than bacterial pneumonia. Ultimately, underlying asthma may have contributed to malnutrition and fatal bacterial pneumonia. In conclusion, preschool asthma in low-income countries may be significantly under-diagnosed and misdiagnosed as pneumonia, and may be the cause of much morbidity and mortality.

Allergic Rhinitis and Its Impact on Asthma in Asia Pacific and the ARIA Update 2008

The prevalence of allergic diseases such as allergic rhinitis (AR) and asthma are markedly increasing to epidemic proportions worldwide as societies adopt Western lifestyles. An estimated 300 million persons worldwide have asthma, about 50% of whom live in developing countries, and about 400 million people suffer from AR. AR has a marked impact on quality of life, socially, at school, and in the workplace and is a huge socioeconomic burden. Thus, there was clearly a need for a global evidence-based guideline not only for managing AR but also highlighting the interactions between the upper and lower airways including diagnosis, epidemiology, common risk factors, management, and prevention. The Allergic Rhinitis and its Impact on Asthma (ARIA) document was first published in 2001 as a state-of-the-art document for the specialist, the general practitioner, and other health care professionals. Subsequent research and increasing knowledge have resulted in the ARIA 2008 update. The present review summarizes the ARIA update with particular emphasis on the current status of AR and asthma in Asia Pacific.

Prevalence of bronchial asthma in Indian children

BACKGROUND

The prevalence of childhood bronchial asthma and allergic disease has increased in developed countries. Studies have identified asthma among Indian children. Still, there is paucity of information on the overall prevalence of childhood asthma in India.

OBJECTIVE

To assess time trends and the overall prevalence rate of bronchial asthma among Indian children.

MATERIALS AND METHODS

Literature search for data sources was done through an extensive search in indexed literatures and website-based population survey reports. Fifteen epidemiological studies were identified on the development of asthma in Indian children from 300 potentially relevant articles. A broad criterion to define both allergic and non-allergic descriptions of asthma in Indian children was formed. Moreover, in the absence of universally accepted criteria by reporting of prevalence by researchers, weighted average data was considered during calculations of prevalence rates, irrespective of the criteria for diagnosis. Statistical analyses used were mean and median.

RESULTS

Wide differences in samples, primary outcome variables, lack of consistency in age category, rural-urban variation, criteria for positive diagnosis, and study instruments confounded the outcome variables. The mean prevalence was 7.24 +/- SD 5.42. The median prevalence was 4.75% [with IQR = 2.65 - 12.35%]. Overall weighted mean prevalence was found to be 2.74. Childhood asthma among children 13 - 14 years of age was lower than the younger children (6 - 7 years of age). Urban and male predominance with wide inter-regional variation in prevalence was observed.

CONCLUSIONS

Our findings indicate that the burden of bronchial asthma in Indian children is higher than was previously understood.

Risk factors and prevalence of asthma in schoolchildren in Castellon (Spain): a cross-sectional study

BACKGROUND

Research on potential risk factors of asthma can enhance our understanding of geographic differences and inform decisions on preventive strategies.

METHODS

In 2002, a cross-sectional population-based study was carried out in the area of Castellon (Spain), following the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III methodology. Asthma symptoms and related risk factor questionnaires were completed by parents of 6-7 year-old schoolchildren. Logistic regression was used in the analysis.

RESULTS

Participation rate was 88 % (4492 of 4872 schoolchildren). Prevalence of wheeze in the past year, asthma ever, and physician-diagnosed asthma were 8 %, 7 % and 6 %, respectively. Risk factors independently associated with all three asthma case definitions were history of bronchitis or pneumonia, allergic rhinitis, family members with atopic disease, and residing in an industrialised area. Risk factors for asthma ever and physician-diagnosed asthma were male sex, atopic eczema and presence of a dog at home; exclusive breast-feeding and the presence of another animal (not a dog or cat) were protective factors. Maternal age was inversely related to physician-diagnosed asthma. Residence in an area of heavy truck traffic and the father smoking at home were associated with asthma ever. Risk factors for wheeze in the past year were low social class, history of sinusitis and the father smoking at home.

CONCLUSIONS

Environmental factors are related to the presence of asthma. Preventive measures should be directed to improving air pollution, promoting breast-feeding and reducing smoking in the home.