Prevalence of symptoms of asthma and allergies in schoolchildren in Gondar town and its vicinity, northwest Ethiopia

Association between helminth infection and allergic disorders among children in Batu, Ethiopia

BACKGROUND

Helminths are potent immunomodulators and in their chronic infection state they may protect against allergy-related disease and atopy. However, they are also known for inducing allergic conditions. This study aimed to assess the association between helminths,  atopy and allergic conditions.

METHODS

A total of 461 school children participated in this cross-sectional study. Data on allergic symptoms and a range of confounding variables was gathered from parents via an interviewer-led questionnaire. Skin sensitization to house dust mite and cockroaches was analyzed, and a stool sample was collected for helminth analysis. Serum total Immunoglobulin E using enzyme-linked immunosorbent assay and eosinophil count were also measured.

RESULTS

Overall sensitivity to both allergens was 2.4%. Self-reported allergic outcomes in the last 12 months for the 461 participants had been : wheezing 3.7%, asthma 2.2%, eczema 13.2% and hay fever 6.9%. Overall, the prevalence of helminth infection was 11.9% (53/444). A borderline significant association was found between atopy and any allergy symptoms (odds ratio [OR]: 3.32, 95% confidence interval [95% CI: 0.99, 11.1], p = .052). There was no significant association between helminths and atopy (OR: 0.64 [95% CI: 0.29, 1.41], p = .268) and also between helminths and allergic symptoms (OR: 0.64 [95% CI: 0.29, 1.41], p = .268). Bivariate analysis showed keeping an animal in the house increases the risk of atopy while maternal and paternal history of allergy increases the risk of developing allergic symptoms in the children.

CONCLUSION AND CLINICAL RELEVANCE

This study found a non-significant inverse association between helminths infection and atopy and allergic disorders, likely due to reduced statistical power, resulting in a lower prevalence of atopy and allergic conditions. A high powered longtitudinal study is necessary to explore the casuality and potential therapeutic benefits of helminths for allergic disorders.

Prevalence of asthma in patients with atopic dermatitis: A systematic review and meta-analysis

BACKGROUND

It is well established that asthma is common in patients with atopic dermatitis (AD).

OBJECTIVES

We performed a systematic review and meta-analysis to determine the prevalence of asthma and respiratory symptoms in individuals with AD as well as the association between AD and asthma.

METHODS

At least 2 authors independently searched the medical databases PubMed, EMBASE, LILACS, and SCOPUS for all English-language studies with data on asthma prevalence among patients with AD or the association between AD and asthma. Pooled odds ratios with 95% confidence intervals (CIs) and pooled proportions were estimated with random-effects models. The Newcastle-Ottawa scale was used to assess study quality.

RESULTS

The search yielded 39,503 articles. Of these, 213 studies were included in a quantitative analysis. The overall pooled prevalence of asthma was 25.7% (95% CI, 23.7-27.7) in patients with AD and 8.1% (95% CI, 7.0-9.4) among reference individuals. There was a significant association between AD and asthma when compared with reference individuals (odds ratio, 3.03; 95% CI, 2.64-3.47).

LIMITATIONS

The definitions of AD and asthma differed across the included studies and varied from self-report to physician diagnosed.

CONCLUSIONS

Asthma is a common comorbidity of AD. Physicians should be cognizant of this relationship and address asthma symptoms in their patients.

Asia-Pacific Survey of Physicians on Asthma and Allergic Rhinitis (ASPAIR): physician beliefs and practices about diagnosis, assessment, and treatment of coexistent disease

Background

Asthma and allergic rhinitis (AR) frequently coexist, and having both asthma and AR is associated with uncontrolled asthma and a heavier disease burden. The Asia-Pacific Survey of Physicians on Asthma and Allergic Rhinitis (ASPAIR) aimed to assess physicians’ perceptions and their management practices for patients with coexistent disease.

Materials and methods

A total of 1,204 general physicians and pediatricians from six countries in Asia, who routinely treat asthma patients, were interviewed in-person. Physicians were questioned about their attitudes and beliefs of coexistent asthma-AR, how they diagnose and treat patients, and their knowledge of international guideline recommendations.

Results

Physicians reported that 45% of their patients with asthma have coexistent AR and 37% of their patients with AR have coexistent asthma. Most physicians (77%) agreed that coexistent asthma-AR is a genuine condition and that patients suffer worse symptoms with both the conditions vs one alone (86%). Although nearly all agreed that both asthma and AR should be treated (91%) and that intranasal (INS) and inhaled corticosteroids (ICS) could be given concurrently to these patients, 40% also thought that treating both conditions effectively at the same time is difficult, and approximately a quarter believed that corticosteroid therapy should be delayed in children for both asthma and AR. While there was universal recognition and acceptance that guidelines provide sufficient information for treating uncontrolled coexistent disease (≥80% physicians in all countries), physicians revealed that 41% of their asthma patients are treated with short-acting rescue medications alone, and only 47% responded that treatment with concurrent INS and ICS, as recommended in the Allergic Rhinitis and its Impact on Asthma (ARIA) guidelines, was their preferred treatment for coexistent disease.

Conclusion

The ASPAIR survey demonstrates a widespread acceptance of coexistent asthma-AR, and the associated burden, but highlights the need for increased healthcare practitioner communication and awareness to improve appropriate treatment and management of these coexistent conditions.

Allergy-related disorders (ARDs) among Ethiopian primary school-aged children: Prevalence and associated risk factors

Background

There has been a noticeable increase in the prevalence of allergy-related disorders (ARDs) in the modern era. Urbanization is believed to be a major environmental risk factor for the onset of ARDs but data from low- to middle-income countries is limited.

Objective

Our purpose was to assess the prevalence of ARDs and atopy among a population of rural Ethiopian school children and identify environmental and lifestyle factors associated with such disorders.

Methods

We performed a cross-sectional study on 541 school-children. An interviewer-led questionnaire administered to the mothers of each participant provided information on demographic and lifestyle variables. Questions on allergic disease symptoms were based on the International Study of Asthma and Allergies in Children (ISAAC) core allergy and environmental questionnaire. Skin prick test for common allergens German cockroach (Blattella germanica) and dust mite (Dermatophagoides) was performed to define atopy. Multiple logistic regression analyses were performed to determine the odds ratio between ARDs and atopy with specific environmental and lifestyle habits.

Results

541 children responded to the survey questions: the majority of participants were female (60.3%) and aged 10–15 years-old. The prevalence of any ARD was 27%, while the rates of ever-having eczema, rhinitis, and wheeze was found to be 16.8%, 9.6%, and 8.6% respectively. Only 3.6% (19 school-children) tested positive for any skin sensitization. Analysis of associated factors for ARDs found that a family history of allergic disorders (AOR: 2.80; p-value<0.01), use of insecticides (AOR: 2.05; p-value<0.01), and wearing open-toed shoes (AOR: 2.19; p-value = 0.02) were all significantly associated factors. Insecticide use, river-bathing, and infection with intestinal parasites were found to be significantly associated factors for atopy. Other potential risk factors such as frequent use of soap, bacterial infection, and household crowding had no statistical significance.

Conclusion

Our study suggests that the prevalence of skin sensitization and ARDs in rural populations of developing countries is still relatively low. We identified several possible risk factors for further investigation. Overall, the significance of identified risk factors appears to indicate that genetic predisposition and exposure to environmental pollution are more important to the etiology of ARDs and atopy than specific lifestyle behaviors.

The Role of Helminth Infection and Environment in the Development of Allergy: A Prospective Study of Newly-Arrived Ethiopian Immigrants in Israel

Helminth infection may be protective against allergy and account for the low prevalence of allergy in developing countries. We studied prospectively the prevalence of allergy in Ethiopian immigrants with heavy helminth infection on arrival in Israel, and again after a year of adjustment to an urban industrialized setting, to explore the roles of helminth infection, changed environment and background immunity on the manifestations of allergy. 126 newly arrived Ethiopian immigrants were studied at baseline and 115 after a year of follow up in Israel. Allergic symptoms, Skin prick tests (SPT), Tuberculin (PPD) skin tests, stool and blood samples were obtained for determining parasites, blood IgE and eosinophil levels, respectively. Anti-helminthic therapy was offered to the entire infected individuals, but only 50/108 (46.3%) took the medication. At baseline, there was a significant negative association between helminth infection and allergy, 4/18 (22.2%) of uninfected participants were allergic compared to 7/108 (6.5%) of helminth-infected participants (p = 0.028), as well as between helminth infection and SPT reactivity, 12/18 (66.6%) of uninfected participants compared to 43/108 (39.8%) of helminth-infected participants (p = 0.033). After one year, a significant general increase in allergy and SPT was observed. While only 11/126 (8.7%) were allergic at baseline, 30/115 (26.1%) became allergic at follow-up (p<0.0001), and while 55/126 (43.7%) were SPT+ at baseline, 79/115 (68.7%) became SPT+ at follow-up (p<0.001). A twofold increase in allergen sensitization was also observed after one year in Israel, particularly for dust mites, grasses and olive tree (p<0.001). These results show that: a) Helminth infection is significantly associated with low allergy and low SPT reactivity; b) One year after immigration to Israel, allergy and SPT reactivity increased significantly in all immigrants; c) Higher increases in positive SPT and allergy were observed after a year in the group that remained infected with helminths, even though they had a lowered helminth load; d) The reasons for the increased allergy one year after immigration needs further investigation but probably reflects the combined influence of the decreased helminth load and novel environmental factors.

The role of intestinal parasitic infections in allergy is of great interest since it has been suggested that they suppress the development of allergy. Urbanization has also been claimed to cause allergy because of air pollution and higher exposure to allergens. The present study took advantage of the special opportunity presented by the recent Ethiopian immigration to Israel in order to study this question. A cohort of newly arrived Ethiopian immigrants to Israel, highly infected with parasites, was studied prospectively for the presence of allergy and response to allergens on arrival and after a year of follow up in Israel. The results showed clearly a significant inverse association between the presence of parasitic infections and allergy on arrival, while after a year of living in Israel, accompanied by a lowered parasitic infection load, a general increase of allergy was observed in all immigrant groups, and not only in those that had parasitic infections on arrival. These results lend support to the suppressive effect of intestinal parasites on allergy, but suggest that additional factors, most probably environmental, also play a role in the generation of allergy.

Interrelationships between Atopic Disorders in Children: A Meta-Analysis Based on ISAAC Questionnaires

Purpose

To study the prevalence and interrelationship between asthma, allergic rhinitis and eczema using data obtained from ISAAC questionnaires.

Method

The Medline, Pubmed Publisher, EMBASE, Google Scholar and the Cochrane Controlled Clinical Trials Register databases were systematically reviewed to evaluate epidemiological data of children with atopic disorders. To study these interrelationships, a new approach was used. Risk ratios were calculated, describing the risk of having two different atopic disorders when the child is known with one disorder.

Results

Included were 31 studies, covering a large number of surveyed children (n=1,430,329) in 102 countries. The calculated worldwide prevalence for asthma, eczema and allergic rhinitis is 12.00% (95% CI: 11.99-12.00), 7.88% (95% CI: 7.88-7.89) and 12.66% (95% CI: 12.65-12.67), respectively. The observed prevalence [1.17% (95% CI: 1.17-1.17)] of having all three diseases is 9.8 times higher than could be expected by chance. For children with asthma the calculated risk ratio of having the other two disorders is 5.41 (95% CI: 4.76-6.16), for children with eczema 4.24 (95% CI: 3.75-4.79), and for children with allergic rhinitis 6.20 (95% CI: 5.30-7.27). No studied confounders had a significant influence on these risk ratios.

Conclusions

Only a minority of children suffers from all three atopic disorders, however this co-occurrence is significantly higher than could be expected by chance and supports a close relationship of these disorders in children. The data of this meta-analysis supports the hypothesis that there could be a fourth distinct group of children with all three disorders. Researchers and clinicians might need to consider these children as a separate group with distinct characteristics regarding severity, causes, treatment or prognosis.

An estimate of asthma prevalence in Africa: a systematic analysis

Aim

To estimate and compare asthma prevalence in Africa in 1990, 2000, and 2010 in order to provide information that will help inform the planning of the public health response to the disease.

Methods

We conducted a systematic search of Medline, EMBASE, and Global Health for studies on asthma published between 1990 and 2012. We included cross-sectional population based studies providing numerical estimates on the prevalence of asthma. We calculated weighted mean prevalence and applied an epidemiological model linking age with the prevalence of asthma. The UN population figures for Africa for 1990, 2000, and 2010 were used to estimate the cases of asthma, each for the respective year.

Results

Our search returned 790 studies. We retained 45 studies that met our selection criteria. In Africa in 1990, we estimated 34.1 million asthma cases (12.1%; 95% confidence interval [CI] 7.2-16.9) among children <15 years, 64.9 million (11.8%; 95% CI 7.9-15.8) among people aged <45 years, and 74.4 million (11.7%; 95% CI 8.2-15.3) in the total population. In 2000, we estimated 41.3 million cases (12.9%; 95% CI 8.7-17.0) among children <15 years, 82.4 million (12.5%; 95% CI 5.9-19.1) among people aged <45 years, and 94.8 million (12.0%; 95% CI 5.0-18.8) in the total population. This increased to 49.7 million (13.9%; 95% CI 9.6-18.3) among children <15 years, 102.9 million (13.8%; 95% CI 6.2-21.4) among people aged <45 years, and 119.3 million (12.8%; 95% CI 8.2-17.1) in the total population in 2010. There were no significant differences between asthma prevalence in studies which ascertained cases by written and video questionnaires. Crude prevalences of asthma were, however, consistently higher among urban than rural dwellers.

Conclusion

Our findings suggest an increasing prevalence of asthma in Africa over the past two decades. Due to the paucity of data, we believe that the true prevalence of asthma may still be under-estimated. There is a need for national governments in Africa to consider the implications of this increasing disease burden and to investigate the relative importance of underlying risk factors such as rising urbanization and population aging in their policy and health planning responses to this challenge.

International Health Links movement expands in the United Kingdom

The need to strengthen health capacity in developing countries is widely documented. The World Health Organization has called for an increase in the number of health workers in all countries experiencing critical shortages, a significant scaling-up of training and more efficient use of existing health workers. Health Links, long-term mutually beneficial partnerships between UK health institutions and their counterparts in developing countries, are helping to fill these gaps. Links allow for the reciprocal transfer of knowledge and skills between partners, enabling the UK's expertise in health service delivery and training to be channelled towards the needs of those in developing countries, while also bringing a wide range of benefits to the UK. Examples of Health Links in Ethiopia demonstrate such benefits. An increasingly supportive policy environment is enabling a significant expansion in the number of Links. However, the quality of these Links is critical to their impact and thus there is a need both to continue to support those engaging in Links to develop sustainable, mutually beneficial strategic partnerships, and to strengthen the body of evidence of their impacts.

The impact of asthma and COPD in sub-Saharan Africa

BACKGROUND

Many countries in sub-Saharan Africa have the highest risk of developing chronic diseases and are the least able to cope with them.

AIMS

To assess the current knowledge of the prevalence and impact of asthma and chronic obstructive pulmonary disease (COPD) in sub- Saharan Africa.

METHODS

A literature search was conducted using Medline (1995-2010) and Google Scholar.

RESULTS

Eleven studies of the prevalence of asthma in sub-Saharan Africa were identified, all of which showed a consistent increase, particularly in urban regions. The data on asthma show a wide variation (5.7-20.3%), with the highest prevalence in 'westernised' urban areas. Only two studies of the prevalence of COPD in sub-Saharan Africa have been performed. Nevertheless, COPD has become an increasing health problem in sub-Saharan Africa due to tobacco smoking and exposure to biomass fuels. In most countries of sub-Saharan Africa, 90% of the rural households depend on biomass fuel for cooking and heating, affecting young children (acute lower respiratory infections) and women (COPD). This is the cause of significant mortality and morbidity in the region.

CONCLUSIONS

Asthma and COPD in sub-Saharan Africa are under-recognised, under-diagnosed, under-treated, and insufficiently prevented. A major priority is to increase the awareness of asthma and COPD and their risk factors, particularly the damage caused by biomass fuel. Surveys are needed to provide local healthcare workers with the possibility of controlling asthma and COPD.

The burden of allergic rhinitis and asthma

Asthma and allergic rhinitis are common health problems that cause major illness and disability worldwide. The prevalence of allergic rhinitis is estimated to range from 10% to 20% in the USA and Europe. Multiple factors contribute to the wide range of reported prevalence rates. These include type of prevalence rate reported (current or cumulative), study selection criteria, age of participants, differences in survey methods, varied geographic locations and socioeconomic status, any of which are significant enough to confound direct comparison between studies. There is no standard set of diagnostic criteria for allergic rhinitis. In most studies, the criteria for diagnosis are based on the subject's reporting, solely by questionnaire and rarely confirmed by skin testing. In addition, most studies focus on hay fever, leaving perennial allergic rhinitis underestimated. Sinus imaging is generally not performed and, therefore, rhinosinusitis not differentiated. Some investigators report 'current' prevalence while others report 'cumulative' or 'lifetime' prevalence. Epidemiologic studies have consistently shown that asthma and rhinitis often coexist in the same patients. The prevalence of asthma is <2% in subjects without rhinitis while it varies from 10% to 40% in patients with rhinitis. Furthermore, the majority of patients with asthma experience rhinitis, which is a factor in the risk for asthma. Despite recognition that allergic rhinitis and asthma are global health problems, there are insufficient epidemiologic data and more data are needed with regard to their etiologic risk factors and natural history. This aim of this review is to enable the reader to discuss prevalence, risk factors and prognosis of allergic rhinitis and asthma.

Prevalence and diversity of allergic rhinitis in regions of the world beyond Europe and North America

BACKGROUND

There is comparatively little information in the public domain on the diversity in prevalence and triggers/factors associated with allergic rhinitis (AR) or allergic rhinoconjunctivitis (AR/C) in countries beyond western-Europe and North America.

OBJECTIVE

To review the prevalence and the sensitizing agents/triggers and factors associated with AR/C in several countries in Africa, the Asia-Pacific region, Australia, Eastern Europe, Latin America, Middle East and Turkey.

METHODS

Articles published in English in peer-reviewed journals were assessed and selected for further review, following an extensive literature search using the Medline database.

RESULTS

This review demonstrated that prevalence of AR and AR/C in these regions has predominantly been investigated in children; with studies indicating wide inter- and intra-regional variations ranging from 2.9% AR and 3.8% AR/C in 10-18-years-old children from one region in Turkey to 54.1% AR and 39.2% AR/C in 13-14-years-old children in one region in Nigeria. Moreover, the prevalence of AR and AR/C has increased markedly over the last decade particularly in some of the more affluent African countries, China-Taiwan and several Middle East countries, likely as a consequence of improved living standards leading to increased exposure to multiple traditional and non-traditional sensitizing agents and risk factors similar to those noted in western-Europe and North America.

CONCLUSIONS AND CLINICAL RELEVANCE

Our findings suggest that the greater diversity in prevalence of AR or AR/C in populations in these regions is in contrast to the lower diversity of AR or AR/C in the 'western populations (USA and Europe), which tend to be more uniform. This review provides a comprehensive database of the important allergens and triggers which are likely to influence the prevalence of allergic rhinitis in these diverse regions, where the prevalence of allergic rhinitis is increasing and its adverse impact on the quality of life of affected individuals is increasingly recognised.

Atopy is associated with asthma in adults living in rural and urban southwestern Nigeria

RATIONALE

Factors affecting the course of asthma are not clearly understood in rural and urban communities within low-resource countries. Furthermore, the interactions between atopy, environmental exposure, and helminthic infections in modulating asthma have not been well investigated.

OBJECTIVES

To conduct a feasibility study to examine the relationship between atopy and asthma in adults at two rural Health Centers and urban university college hospital in southwestern Nigeria.

METHODS

A convenient sample of 55 consecutive patients with stable physician-diagnosed asthma and 55 age-matched nonasthmatic controls seen at the outpatient clinics in two rural Health Centers and an urban university hospital were enrolled. All subjects underwent blood test, allergy skin test, and stool examination for ova and parasites. Wilcoxon sign-rank tests were used to compare serum eosinophilia and allergy skin test between the two groups.

RESULTS

Asthmatics in both urban and rural settings had significantly more positive skin reactions to house dust mite, cockroach, mold, and mouse epithelium than nonasthmatic controls (p < .05). Mean total serum IgE was also significantly higher in asthmatics than in nonasthmatic controls (360 vs. 90 IU/L, p <.001). Stool parasitemia was infrequent in both groups and not statistically significant.

CONCLUSION

Atopy is associated with adult asthma in southwest Nigeria. Larger studies to confirm the nature of this association and to examine the role of helminthic infection and other environmental factors on the expression of asthma are needed.

Importance of allergic rhinitis management in achieving asthma control: ARIA update

Asthma continues to be a major burden for the health and healthcare of people worldwide. The recent updates of the Global Initiative for Asthma and the National Heart, Lung and Blood Institute asthma guidelines stress the need for achieving and monitoring asthma 'control', emphasizing the importance of identifying, assessing and treating comorbid conditions. Allergic rhinitis (AR) is a major comorbid condition in people with asthma and is related to inflammation of the upper portions of the airway. Recognizing and treating AR has been shown to improve asthma control, specifically by decreasing rates of asthma attacks or asthma exacerbations. In 2008, updated Allergic Rhinitis in Asthma (ARIA) guidelines were published. The updated version of the guidelines has a familiar look, with classification systems and care algorithms that are similar to those presented in other asthma guidelines. The new ARIA guidelines make one major change that should affect the care of adults and children with asthma: everyone with asthma should be assessed for AR. In addition, AR should be considered a risk factor for asthma, and all children and adults with AR, especially persistent AR, should be assessed for asthma, including testing lung function for reversible obstruction whenever feasible. Treatment for AR follows a similar format to that for asthma, including symptom management, treatment of chronic inflammation, identification and management of triggers, including allergens, and ongoing education for self-management. Pharmacotherapies that address both asthma and AR include corticosteroids (intranasal and inhaled), leukotriene receptor antagonists, immunomodulation or immunotherapy. Too often, pharmacotherapy is not supplemented by the necessary education and evaluation related to allergen, trigger identification and management.

Is the prevalence of asthma declining? Systematic review of epidemiological studies

Asthma prevalence has increased very considerably in recent decades such that it is now one of the commonest chronic disorders in the world. Recent evidence from epidemiological studies, however, suggests that the prevalence of asthma may now be declining in many parts of the world, which, if true is important for health service planning and also because this offers the possibility of generating and testing new aetiological hypotheses. Our objective was to determine whether the prevalence of asthma is declining worldwide. We undertook a systematic search of EMBASE, Medline, Web of Science and Google Scholar, for high quality reports of cohort studies, repeat cross-sectional studies and analyses of routine healthcare datasets to examine international trends in asthma prevalence in children and adults for the period 1990-2008. There were 48 full reports of studies that satisfied our inclusion criteria. The large volume of data identified clearly indicate that there are, at present, no overall signs of a declining trend in asthma prevalence; on the contrary, asthma prevalence is in many parts of the world still increasing. The reductions in emergency healthcare utilization being reported in some economically developed countries most probably reflect improvements in quality of care. There remain major gaps in the literature on asthma trends in relation to Africa and parts of Asia. There is no overall global downward trend in the prevalence of asthma. Healthcare planners will for the foreseeable future, therefore, need to continue with high levels of anticipated expenditure in relation to provision of asthma care.

Common characteristics of upper and lower airways in rhinitis and asthma: ARIA update, in collaboration with GA(2)LEN

This update aimed to review the new evidence available to support or refute prior Allergic Rhinitis and its Impact on Asthma (ARIA) statements. A Medline search of publications between 2000 and 2005 was conducted, with articles selected by experts. New evidence supports previous ARIA statements, such as: (i) allergic rhinitis (AR) is a risk factor for asthma; (ii) patients with persistent rhinitis should be evaluated for asthma; (iii) most patients with asthma have rhinitis; (iv) a combined strategy should be used to treat the airways and (v) in low- to middle-income countries, a different strategy may be needed. The increased risk of asthma has also been found among sufferers from non-AR. Recent reports show AR is a global problem. Many studies demonstrated parallel increasing prevalence of asthma and rhinitis, but in regions of highest prevalence, it may be reaching a plateau. Factors associated with a reduced risk of asthma and AR have been identified, confirming previous findings of protection related to exposure to infections. Treatment of rhinitis with intranasal glucocorticosteroids, antihistamines, leukotriene antagonists or immunotherapy may reduce morbidity because of asthma. To take advantage of the paradigm of unified airways, there is a need to rationalize diagnosis and treatment to optimize management.

Asthma and allergies in schoolchildren of Maputo

AIM

The study aimed to determine prevalence and severity of asthma, rhinitis and eczema in Maputo, Mozambique.

METHODS

The International Study of Asthma and Allergies (ISAAC) protocol was applied in 27 schools in urban, suburban and semi-rural areas.

RESULTS

A total of 2630 completed questionnaires were obtained from students aged 13-14 years, and 2383 from schoolchildren aged 6-7 years. The prevalence of current asthma was 13.3% in the two groups, the prevalence of rhinoconjuctivitis and eczema was 23% and 10% in teenagers and 8.8% and 8.5% respectively in children 6-7 years old. Overall, 35% of the adolescents and 23.8% of children were found to have at least one atopic condition or asthma in the last year. In symptomatic adolescents, the conditions were: rhinoconjuctivitis (41.3%), asthma (20%) and eczema (12.4%). In symptomatic children, asthma was the principal condition (36.2%), followed by eczema (20.3%) and rhinoconjunctivitis (19.1%). In adolescents, asthma was more frequently associated with rhinoconjuctivitis (28%). About 4% of all surveyed children had three atopic conditions associated. In adolescents, past year rhinitis was more frequent and severe in the urban area. Hay fever was commoner in the semi-urban area. Eczema was significantly more recurrent in suburban and semi-rural area. Exercise-induced wheeze, nocturnal cough and ever asthma were more reported in children of suburban area.

CONCLUSION

Asthma and allergic diseases are important public health problems in Maputo and improvement in prevention and management plans are required.

Validation of the International Study of Asthma and Allergies in Children (ISAAC) and U.K. criteria for atopic eczema in Ethiopian children

BACKGROUND

Reliable diagnostic criteria for atopic eczema (AE) are essential in order to make international comparisons and to identify possible disease risk factors. Little is known about the prevalence of atopic eczema and validity of diagnostic criteria for AE in developing countries where English is not the first language.

OBJECTIVES

We sought to determine the prevalence of AE in an area of urban and rural Ethiopia, and to compare the predictive values of different questionnaire and examination methods for diagnosing AE in this population.

METHODS

We conducted a cross-sectional survey of 7915 children aged 1-5 years living in and around the town of Jimma in southwest Ethiopia. AE prevalence was assessed in two ways: (i) by using the International Study for Asthma and Allergies in Childhood (ISAAC) questionnaire, and (ii) using the U.K. refinement of Hanifin and Rajka's diagnostic criteria. All possible cases identified by screening questions and random samples of controls were then examined by an experienced local paediatrician, who acted as a reference standard to determine the predictive value of the criteria used to diagnose AE.

RESULTS

The overall 1-year period prevalence of AE according to ISAAC and U.K. criteria was 4.4%[95% confidence interval (CI) 3.95-4.85] and 1.8% (95% CI 1.5-2.1), respectively. Corresponding point prevalence estimates (symptoms in the last week) were 1.8% for ISAAC and 1.3% for the U.K. criteria. The positive predictive values of the ISAAC and U.K. criteria questions for AE symptoms still reported to be present (in the last week) at the doctor's examination were 48.8% and 55.5%, respectively. Corresponding negative predictive values were 90.5% and 90.1%, respectively. The sign of visible flexural dermatitis (a component of the U.K. criteria) when used alone had positive and negative predictive values of 57% and 91%, respectively.

CONCLUSIONS

Neither the ISAAC nor U.K. criteria performed especially well in predicting cases of AE in this survey. Possible reasons include problems with questionnaire translation, cultural conceptions of terminology, asking parents rather than the child about symptoms, the transient nature of AE signs, and differences in what a doctor perceives to constitute a typical case of AE. The results do not preclude the use of standardized diagnostic criteria alongside a doctor's examination in future surveys of Ethiopian children, and knowledge of the criteria's limited predictive value should help to interpret study findings that have employed such criteria. Consideration should be given to adopting the sign of visible flexural dermatitis as a standard for estimating the point prevalence of AE throughout the world because it is less susceptible to problems with translation and interpretation.

Parent-reported asthma in Puerto Rican children

We conducted a survey to determine parent-reported asthma prevalence, morbidity, and healthcare utilization among 3527 children attending public schools (n = 2849) and private schools (n = 678) in San Juan, Puerto Rico. Schools were randomly selected from each of 12 geographic regions of the San Juan metropolitan area. Parents of children age 4-7 years old completed a 12-item questionnaire on asthma diagnosis, respiratory symptoms and morbidity, and healthcare utilization. Parents of children in public schools and private schools reported similar rates of a physician having previously diagnosed asthma in their children (43.2% vs. 39.4%); however, significantly more children in public schools were reported to still have asthma at the time of the survey (32.6% vs. 23.7%). Children attending public schools vs. private schools were reported to have missed significantly more school and to have had more hospitalizations and emergency department visits. Among children reported to still have asthma, significantly more children visited an emergency department, were hospitalized, and missed more school days due to respiratory symptoms in the past year. The high prevalence of parent-reported asthma, respiratory symptoms, and healthcare utilization among Puerto Rican children in San Juan calls for further studies using objective methods for ascertaining asthma and asthma-related morbidity. Differences in healthcare utilization between children attending public vs. private schools suggest that socioeconomic factors play a role in asthma management in Puerto Rico.

Is there a causative role for tetanus toxoid vaccination in the development of allergy-like symptoms and in the increasing prevalence of atopic diseases?

Allergic diseases are a worldwide health problem. They mainly affect people living in developed countries where an increasing prevalence of allergy symptoms has been recorded in the last 20-30 years. The cause of this increase is still disputed, and, among others, the "hygiene hypothesis" supported the concept that relevant changes in lifestyle could have a relationship with the phenomenon. More recently the recorded parallel increase in autoimmune diseases has suggested to consider the "hygiene hypothesis" as a cause of a more general disregulation of the immune system leading to both allergy and to autoimmunity. Here are reported a series of observations, evidence, and data from the literature leading to a different hypothesis. The key points are: (1) the presence of two subsets of patients having allergy symptoms based on an IgE-mediated mechanism or not; (2) the positive results obtained with the autologous serum skin test in either cutaneous or respiratory affected subjects, mainly in children and adult females; (3) the presence of IgG autoantibodies against the alpha-chain of the high affinity IgE receptor (FcepsilonRIalpha) in non-IgE-mediated urticaria and even in respiratory subjects; (4) the cross-reactivity between epitopes of the tetanus toxoid molecule and the FcepsilonRIalpha detected by means of an alpha-chain affinity purified IgG fraction; (5) the positive skin reactivity obtained using IgG anti-tetanus toxoid preparations in allergic and non-allergic volunteers. The presence of IgG autoantibodies actively generated by the population-based vaccination with tetanus toxoid could induce both mediator release from activated mast cell and Th2 cytokine production early in life. There are epidemiological evidences that tetanus toxoid vaccination could be linked with an increased tendency to have allergy symptoms. The different epidemiological distribution of non-IgE-mediated symptoms, mainly affecting young infants would be in agreement with the present hypothesis. The prevalent mother-to-child relationship in terms of risk for allergy symptoms could be explained with the trans-placenta transfer of IgG. A similar transfer could also take place through the mother milk during breast feeding. It may thus be hypothesized that the increased prevalence of allergic diseases could be caused by the generalized tetanus toxoid immunization procedure, progressively extended to most of the countries worldwide in the last 30-40 years. Both the induction of non-IgE-mediated symptoms caused by the mast cell activation via the anti-FcepsilonRIalpha IgG and the long lasting Th2 inflammation of affected tissues would be the inducing mechanisms. This hypothesis would re-configure part of the allergic diseases as a Th2 phenotypic expression of an autoimmune disease.