Prevalence of childhood asthma, rhinitis and eczema in Scandinavia and Eastern Europe

Production, analysis, and safety assessment of a soil and plant-based natural material with microbiome- and immune-modulatory effects

It has been suggested that reduced contact with microbiota from the natural environment contributes to the rising incidence of immune-mediated inflammatory disorders (IMIDs) in western, highly urbanized societies. In line with this, we have previously shown that exposure to environmental microbiota in the form of a blend comprising of soil and plant-based material (biodiversity blend; BDB) enhances the diversity of human commensal microbiota and promotes immunoregulation that may be associated with a reduced risk for IMIDs. To provide a framework for future preclinical studies and clinical trials, this study describes how the preparation of BDB was standardized, its microbial content analysed and safety assessments performed. Multiple batches of BDB were manufactured and microbial composition analysed using 16S rRNA gene sequencing. We observed a consistently high alpha diversity and relative abundance of bacteria normally found in soil and vegetation. We also found that inactivation of BDB by autoclaving effectively inactivates human and murine bacteria, viruses and parasites. Finally, we demonstrate that experimental mice prone to develop IMIDs (non-obese diabetic, NOD, mouse model) can be exposed to BDB without causing adverse effects on animal health and welfare. Our study provides insights into a potentially safe, sustainable, and cost-effective approach for simulating exposure to natural microbiota, which could have substantial impacts on health and socio-economic factors.

Decreasing prevalence of atopic dermatitis in Swedish schoolchildren: three repeated population-based surveys

BACKGROUND

The prevalence of atopic dermatitis (AD) has increased over several decades and now affects about one-fifth of all children in high-income countries (HICs). While the increase continues in lower-income countries, the prevalence of AD might have reached a plateau in HICs.

OBJECTIVES

To investigate trends in the prevalence of AD and atopic comorbidity in schoolchildren in Sweden.

METHODS

The study population consisted of three cohorts of children (median age 8 years) in Norrbotten, Sweden, for 1996 (n = 3430), 2006 (n = 2585) and 2017 (n = 2785). An identical questionnaire that included questions from the International Study of Asthma and Allergies in Childhood (ISAAC) protocol was used in all three cohorts. Trends in AD prevalence were estimated, as well as trends in atopic comorbidity. AD prevalence was estimated both according to the ISAAC definition of AD and by adding the reported diagnosis by a physician (D-AD).

RESULTS

The prevalence of AD decreased in the last decade, from 22.8% (1996) and 21.3% (2006) to 16.3% (2017; P < 0.001). The prevalence of D-AD was lower, but the same pattern of decrease was seen, from 9.3% (1996) and 9.4% (2006) to 5.7% (2017; P < 0.001). In all three cohorts, AD was more common among girls than boys (18.9% vs. 13.8% in 2017; P < 0.001). Children from the mountain inlands had a higher prevalence of AD than children from coastal cities (22.0% vs. 15.1% in 2017; P < 0.001). In comparing D-AD, there were no significant differences between the sexes or between inland or coastal living. Concomitant asthma increased over the years from 12.2% (1996) to 15.8% (2006) to 23.0% (2017; P < 0.001). Concomitant allergic rhinitis and allergic sensitization increased from 1996 (15.0% and 27.5%) to 2006 (24.7% and 49.5%) but then levelled off until 2017 (21.0% and 46.7%).

CONCLUSIONS

The prevalence of AD among schoolchildren in Sweden decreased over the study period, whereas atopic comorbidity among children with AD increased. Although a decrease was seen, AD is still common and the increase in atopic comorbidity among children with AD, especially the increase in asthma, is concerning.

[A Study of the Prevalence of Asthma in the General Population in Spain]

Introduction

Asthma is a disease with high prevalence, which affects all age groups and generates high health and social care costs. Studies carried out in a number of populations show great variability in its prevalence, even in geographically close populations, with data suggesting a relevant influence of socio-economic factors. At present, we do not have reliable data on the prevalence of this disease in the adult population of Spain. The objectives of this study are to estimate the prevalence of asthma in the Spanish population for those aged 18-79, to describe the variability between autonomous communities, to estimate the prevalence of under and overdiagnosis, to analyse the prevalence of uncontrolled asthma and steroid-dependent asthma, to evaluate the health care cost, to identify the most frequent phenotypes and to establish a starting point to evaluate the temporal trend with subsequent studies.

Methods

A cross-sectional, two-stage study will be carried out, including patients from 50 catchment areas. The study will be carried out in 3 phases: 1) screening and confirmation in the clinical history, in which patients with a previously correctly established diagnosis of asthma will be identified; 2) diagnosis of asthma to evaluate patients without a confirmed or excluded diagnosis; 3) characterization of asthma, where the characteristics of the asthmatic patients will be analysed, identifying the most frequent phenotypes.

Discussion

It seems necessary and feasible to carry out an epidemiological study of asthma in Spain to identify the prevalence of asthma, to optimize healthcare planning, to characterize the most frequent phenotypes of the disease, and to evaluate inaccurate diagnoses.

A short history from Karelia study to biodiversity and public health interventions

Contact with natural environments enriches the human microbiome, promotes immune balance and protects against allergies and inflammatory disorders. In Finland, the allergy &amp; asthma epidemic became slowly visible in mid 1960s. After the World War II, Karelia was split into Finnish and Soviet Union (now Russia) territories. This led to more marked environmental and lifestyle changes in the Finnish compared with Russian Karelia. The Karelia Allergy Study 2002–2022 showed that allergic conditions were much more common on the Finnish side. The Russians had richer gene-microbe network and interaction than the Finns, which associated with better balanced immune regulatory circuits and lower allergy prevalence. In the Finnish adolescents, a biodiverse natural environment around the homes associated with lower occurrence of allergies. Overall, the plausible explanation of the allergy disparity was the prominent change in environment and lifestyle in the Finnish Karelia from 1940s to 1980s. The nationwide Finnish Allergy Programme 2008–2018 implemented the biodiversity hypothesis into practice by endorsing immune tolerance, nature contacts, and allergy health with favorable results. A regional health and environment programme, Nature Step to Health 2022–2032, has been initiated in the City of Lahti, EU Green Capital 2021. The programme integrates prevention of chronic diseases (asthma, diabetes, obesity, depression), nature loss, and climate crisis in the spirit of Planetary Health. Allergic diseases exemplify inappropriate immunological responses to natural environment. Successful management of the epidemics of allergy and other non-communicable diseases may pave the way to improve human and environmental health.

Clinical Efficacy of a Digital Intervention for Patients with Atopic Dermatitis: a Prospective Single-Center Study

INTRODUCTION

Improving disease awareness and treatment adherence is key for the long-term management of atopic dermatitis (AD). Digital interventions can support patients in disease self-management and adopting a healthier lifestyle through behavioral modifications. We aimed to test the clinical efficacy of a digital program in patients with AD.

METHODS

Adults with mild-to-severe AD were recruited for a 6-week feasibility study. The intervention was delivered through a mobile app and consisted of symptom and trigger education, treatment reminders, lifestyle coaching, and healthy lifestyle support. Here we report the secondary outcomes of intervention efficacy on clinical symptoms, as assessed by Scoring Atopic Dermatitis (SCORAD) and Patient-Oriented Eczema Measure (POEM), on health-related quality of life (HR QoL) as assessed by Dermatology Life Quality Index (DLQI), and changes in behaviors related to disease management as assessed by a six-item questionnaire.

RESULTS

Twenty of 21 patients (95.2%) completed the program (81% female, mean age 31.4 years, mean time from diagnosis 26.8 years). Clinical symptoms and patient-reported global severity improved by 44% and 46%, respectively, while HR QoL improved by 41% (p < 0.001 for all measures). Adherence to treatments and preventive measures improved from pre- to post-intervention, including skincare, avoidance of triggers, and disease-related knowledge. A significant interaction was observed between increased treatment adherence and clinical improvement, such that larger clinical improvements were observed in patients with higher treatment adherence.

CONCLUSION

Patients with AD are open to and can benefit from a digitally delivered targeted intervention, as demonstrated by significant improvements in treatment adherence and related clinical outcomes.

The Hygiene Hypothesis - Learning From but Not Living in the Past

Postulated by Strachan more than 30 years ago, the Hygiene Hypothesis has undergone many revisions and adaptations. This review journeys back to the beginnings of the Hygiene Hypothesis and describes the most important landmarks in its development considering the many aspects that have refined and generalized the Hygiene Hypothesis over time. From an epidemiological perspective, the Hygiene Hypothesis advanced to a comprehensive concept expanding beyond the initial focus on allergies. The Hygiene Hypothesis comprise immunological, microbiological and evolutionary aspects. Thus, the original postulate developed into a holistic model that explains the impact of post-modern life-style on humans, who initially evolved in close proximity to a more natural environment. Focusing on diet and the microbiome as the most prominent exogenous influences we describe these discrepancies and the resulting health outcomes and point to potential solutions to reestablish the immunological homeostasis that frequently have been lost in people living in developed societies.

Parallel gradients in FENO and in the prevalences of asthma and atopy in adult general populations of Sweden, Finland and Estonia - A Nordic EpiLung study

The prevalence of asthma is higher in Sweden and Finland than in neighbouring eastern countries including Estonia. Corresponding difference in bronchial eosinophilic inflammation could be studied by F_ENO measurements. We aimed to compare F_ENO in adult general populations of Sweden, Finland, and Estonia, to test the plausibility of the west-east disparity hypothesis of allergic diseases. We conducted clinical interviews (N = 2658) with participants randomly selected from the general populations in Sweden (Stockholm and Örebro), Finland (Helsinki), and Estonia (Narva and Saaremaa), and performed F_ENO (n = 1498) and skin prick tests (SPT) in 1997-2003. The median (interquartile range) of F_ENO (ppb) was 15.5 (9.3) in Sweden, 15.4 (13.6) in Finland and 12.5 (9.6) in Estonia. We found the lowest median F_ENO values in the Estonian centres Saaremaa 13.1 (9.5) and Narva 11.8 (8.6). In the pooled population, asthma was associated with F_ENO ≥25 ppb, odds ratio (OR) 3.91 (95% confidence intervals: 2.29-6.32) after adjusting for SPT result, smoking, gender and study centre. A positive SPT test increased the likelihood of asthma OR 3.19 (2.02-5.11). Compared to Saaremaa, the likelihood of having asthma was higher in Helsinki OR 2.40 (1.04-6.02), Narva OR 2.45 (1.05-6.19), Örebro OR 3.38 (1.59-8.09), and Stockholm OR 5.54 (2.18-14.79). There was a higher prevalence of asthma and allergic airway inflammation in adult general populations of Sweden and Finland compared to those of Estonia. Atopy and elevated F_ENO level were independently associated with an increased risk of asthma. In conclusion, the findings support the earlier west-east disparity hypothesis of allergic diseases.

Contrasting microbiotas between Finnish and Estonian infants: Exposure to Acinetobacter may contribute to the allergy gap

BACKGROUND

Allergic diseases are more common in Finland than in Estonia, which-according to the biodiversity hypothesis-could relate to differences in early microbial exposures.

METHODS

We aimed at defining possible microbial perturbations preceding early atopic sensitization. Stool, nasal and skin samples of 6-month-old DIABIMMUNE study participants with HLA susceptibility to type 1 diabetes were collected. We compared microbiotas of sensitized (determined by specific IgE results at 18 months of age) and unsensitized Estonian and Finnish children.

RESULTS

Sensitization was differentially targeted between populations, as egg-specific and birch pollen-specific IgE was more common in Finland. Microbial diversity and community composition also differed; the genus Acinetobacter was more abundant in Estonian skin and nasal samples. Particularly, the strain-level profile of Acinetobacter lwoffii was more diverse in Estonian samples. Early microbiota was not generally associated with later sensitization. Microbial composition tended to differ between children with or without IgE-related sensitization, but only in Finland. While land-use pattern (ie green areas vs. urban landscapes around the children's homes) was not associated with microbiota as a whole, it associated with the composition of the genus Acinetobacter. Breastfeeding affected gut microbial composition and seemed to protect from sensitization.

CONCLUSIONS

In accordance with the biodiversity hypothesis, our results support disparate early exposure to environmental microbes between Finnish and Estonian children and suggest a significant role of the genus Acinetobacter in the allergy gap between the two populations. The significance of the observed differences for later allergic sensitization remains open.

The use of short-acting beta-2 adrenergic receptor agonists for asthma increased among Finnish and Swedish children from 2006 to 2017

AIM

Paediatric asthma hospitalisation has decreased in Finland, but has remained stable in Sweden. The reasons for these intercountry differences are unclear. The aim of this study was to explore the trend of dispensed asthma medication, including inhaled corticosteroids (ICS), among paediatric populations in the two countries.

METHODS

We explored trends in dispensed asthma medication among paediatric populations aged 0-19 in Finland and Sweden from 2006 to 2017. The Finnish Statistics on Reimbursements for Prescription Medicines and The Swedish Prescribed Drug Register provided data on all dispensed asthma prescriptions.

RESULTS

During the study period, the prevalence of dispensed ICS in paediatric populations was fairly stable in Finland and Sweden. Among children aged 0-4, ICS were 1.5 times more commonly dispensed in Sweden than in Finland. The prevalence of children dispensed short-acting beta-2 adrenergic receptor agonists (SABA) increased in both countries, but rose more in Finland (51%) than in Sweden (27%).

CONCLUSION

Inhaled corticosteroids were more commonly dispensed for children aged 0-4 in Sweden than in Finland during the study period. This study showed an increasing prevalence of children dispensed SABA in Finland and Sweden, particularly in Finland. Differences and trends in asthma medication may effect asthma hospitalisation and asthma deaths.

Epidemiology and direct costs of atopic dermatitis in Poland based on the National Health Fund register (2008-2017)

Introduction

Epidemiological data indicate significant differences in atopic dermatitis (AD) prevalence between countries.

Aim

The purpose of this study is to (i) analyse the recorded prevalence of atopic dermatitis (diagnoses of AD reported to the Polish National Health Fund (NHF)) and to (ii) estimate direct costs of medical care for AD incurred by the NHF.

Material and methods

The analysis was based on data reported to the database of the public payer (NHF). The prevalence rates were calculated using the NHF data and population estimates were obtained from the Central Statistical Office of Poland (GUS).

Results

In 2017, the annual prevalence rate of AD in the Polish population was 32.5 per 10,000 inhabitants (34.7/10,000 for women and 30.1/10,000 for men). The highest prevalence was observed in the youngest age groups (300/10,000 in children up to 4 years of age and 141/10,000 in 5–9-year-olds). The prevalence rate decreased with age and AD was the least prevalent in patients over 85 years of age (4/10,000). In 2008–2017, NHF expenditure on AD treatment varied between PLN 19.9 million (EUR 5.6 million) in 2008 and PLN 28.4 million (EUR 6.5 million) in 2016.

Conclusions

The prevalence rates of AD in Poland estimated on the basis of NHF data are significantly lower than those reported in previous epidemiological studies conducted in Poland and worldwide. This may indicate that the prevalence of AD in the Polish population is underestimated or that there are no adequate disease control measures in patients with a confirmed diagnosis.

Maturation of Gut Microbiota and Circulating Regulatory T Cells and Development of IgE Sensitization in Early Life

Recent studies suggest that the cross-talk between the gut microbiota and human immune system during the first year of life is an important regulator of the later development of atopic diseases. We explored the changes in the gut microbiota, blood regulatory T cells, and atopic sensitization in a birth-cohort of Estonian and Finnish children followed from 3 to 36 months of age. We describe here an infant Treg phenotype characterized by high Treg frequency, the maturation of Treg population characterized by a decrease in their frequency accompanied with an increase in the highly activated Treg cells. These changes in Treg population associated first with the relative abundance of Bifidobacterium longum followed by increasing colonization with butyrate producing bacteria. High bifidobacterial abundance in the neonatal microbiota appeared to be protective, while colonization with Bacteroides and E. coli was associated with later risk of allergy. Estonian children with lower risk of IgE mediated allergic diseases than Finnish children showed an earlier maturation of the gut microbiota, detected as earlier switch to an increasing abundance of butyrate-producing bacteria, combined with an earlier maturation of Treg cell phenotype and total IgE production. The children with established allergic diseases by age 3 showed a decreased abundance of butyrate producing Faecalibacterium. These results suggest that as well as the maintenance of a bifidobacterial dominated gut microbiota is important during the first weeks of life, the overtake by butyrate producing bacteria seems to be a beneficial shift, which should not be postponed.

Respiratory symptoms, asthma and levels of fractional exhaled nitric oxide in schoolchildren in the industrial areas of Estonia

OBJECTIVES

Exposure to air pollutants in the ambient environment has been associated with various respiratory symptoms, and with increased asthma diagnosis, in both children and adults. Most research to date has focussed on core pollutants, such as PM₁₀, PM_2.5, SO₂ and NO₂, and less attention has been given to the effects of industry-specific contamination. The current study aimed to examine the associations between respiratory symptoms, asthma, increased levels of fractional exhaled nitric oxide (FeNO) (as a marker of eosinophilic airway inflammation) and ambient levels of industrial pollutants (such as benzene, phenol, formaldehyde and non-methane hydrocarbons) for schoolchildren living near oil shale industries in Ida-Viru County, Estonia.

METHODS

A total of 1326 schoolchildren from Ida-Viru, Lääne-Viru and Tartu Counties participated in a cross-sectional study, consisting of questionnaires on respiratory symptoms and asthma, as well as clinical examinations to measure FeNO. Dispersion modelling was used to characterize individual-level exposure to industrial air pollutants at each subject's home address. Associations between exposure and respiratory health were investigated using logistic regression analysis, and differences in results between regions were analysed using the Chi-squared test.

RESULTS

The prevalence of respiratory symptoms (p < 0.05) in children living near (i.e. within 5 km) of an oil shale industry site in Ida-Viru County was 2-4 times higher than in children living in the reference area of Tartu County. Children exposed to 1 μg/m³ higher levels of benzene and formaldehyde had a higher odds ratio (OR) of having rhinitis without a cold (OR 1.03, 95% confidence interval (CI) 1.01-1.06), of ever having had attacks of asthma (OR 1.05, 95% CI 1.01-1.10) and of having a dry cough a few days per year (OR 1.05, 95% CI 1.01-1.10). Children exposed to 1 μg/m³ higher levels of benzene, formaldehyde, phenol and non-methane hydrocarbons had a higher odds ratio of having high FeNO levels (≥30 ppb): OR and 95% CI of 1.05, 1.01-1.09; 1.22, 1.06-1.41; 1.01, 1.00-1.01; and 1.75, 1.75-2.62, respectively.

The Prevalence and Risk Factors of Atopic Dermatitis and Clinical Characteristics according to Disease Onset in 19-Year-Old Korean Male Subjects

Background

The natural course of atopic dermatitis (AD) in infancy, childhood, and adolescence is not yet completely known.

Objective

To investigate the prevalence and risk factors of atopic dermatits among 19-year-old Korean male subjects.

Methods

All 19-year-old Korean males must undergo medical examination for conscription. We precisely evaluated the prevalence of AD in three Korean provinces using the information from this physical checkup. AD was diagnosed by experienced dermatologists according to the Hanifin and Rajka criteria. The disease severity was assessed by the scoring of atopic dermatitis (SCORAD) index. In order to investigate the risk factors for AD, a questionnaire was administered to all subjects regarding parental atopic history, geographical characteristics of past habitation, past economic status, number of siblings, parental occupation, etc.

Results

The point prevalence in the Korean provinces ranged from 1.15% to 1.44%. In multivariable analysis, a parental history of AD was a significant risk factor in all 3 disease-onset groups (infancy, childhood, and adolescent onset). In the infancy-onset group, low economic status was also a significant risk factor for AD. The SCORAD index was significantly higher in AD subjects with early onset and those living in small-sized habitations. Moreover, erythema, edema, lichenification, dryness of skin, and sleep loss appeared to be more severe in early-onset cases.

Conclusion

The younger the age of disease onset, the more severe the clinical outcomes in 19-year-old male subjects. In addition, active AD treatment at younger ages might affect the prevalence and the severity of AD in adulthood.

An international comparison of asthma, wheeze, and breathing medication use among children

BACKGROUND

There is variation in childhood asthma between countries with typically higher prevalence in "Westernized" nations. We compared asthma, respiratory symptoms, and medication prevalence in Eastern and Central European regions and Canada.

METHODS

We conducted a cross-sectional survey study of children (5-15 years) from one urban centre in each of Canada, Belarus, Poland, Republic of Georgia (Adjara), Republic of Macedonia, and Ukraine. Surveys were distributed through randomly selected schools to parents (2013-2015).

RESULTS

The prevalence of asthma differed by country from 20.6% in Canada to 1.5% in Ukraine (p < 0.001). This association remained after confounder adjustment. Except for Canada (58.7%) and Poland (42.5%), less than 10% of children with a history of wheeze had a diagnosis of asthma. Regardless of country, more than 50% of children with a diagnosis of asthma used breathing medications in the past year. Finally, except for Georgia (12.1%), all countries had a prevalence of ever wheeze above 20% (23.8% in Poland to 30.9% in Macedonia).

CONCLUSIONS

Despite large differences in asthma prevalence, respiratory morbidity was more comparable suggesting asthma prevalence may be underestimated. Further validation of asthma diagnosis is needed. It is important to promote best diagnostic practices among first contact physicians.

Rural Dwelling and Temporal Trends in Relation to Childhood Asthma and Related Conditions in Belarus: A Repeated Cross-sectional Survey

There is a lack of asthma research in Belarus, with no investigation of temporal trends. The purpose of the study was to determine the prevalence of asthma and related conditions comparing urban and rural children while investigating temporal changes in the region of Grodno, Belarus. A repeated cross-sectional survey design was used. Parents completed surveys on behalf of the child. Data collection was based on the International Study of Asthma and Allergies in Children (ISAAC) survey and included 5020 urban and rural children aged 7-15 years in 2009-2010 and 4953 children in 2014 from the Grodno Region. Asthma prevalence in 2009 was 1.4% compared with 1.8% in 2014, whereas spastic bronchitis prevalence was higher (2009: 6.8%; 2014: 8.5%). After adjustment for confounders, rural dwelling showed a statistically significant inverse association with each of the allergic conditions or symptoms. However, asthma (odds ratio [OR] = 1.01, 95% confidence interval [CI] = 0.69-1.50) was not associated with rural dwelling. A diagnosis of asthma was more likely in 2014 compared with 2009 (OR = 1.57, 95% CI = 1.05-2.33), as was spastic bronchitis (OR = 1.26, 95% CI = 1.06-1.51). Maternal smoking was associated with the presence of respiratory symptoms. The data showed that the prevalence of diagnosed asthma was comparable between urban and rural areas but lower than other regions, there was generally an increase in the prevalence of asthma and related conditions, and that temporal changes did not vary by urban-rural status. The prevalence of spastic bronchitis was over 3 times higher than that of asthma. These findings also suggest that the presence of undiagnosed asthma in children is occurring in the Grodno Region.

Symptom-trigger factors other than allergens in asthma and allergy

Several environmental exposures of particular relevance for indoor air quality, such as exposure to odorants, may be associated with asthma and allergy. The aim of this study was to investigate attribution of symptoms and behavioral disruptions to various chemical and physical environmental sources in persons with self-reported asthma and allergy. Data from a population-based study, the Västerbotten Environmental Health Study, were used to compare persons with asthma, allergic rhinitis, allergic dermatitis, multiple diagnoses of asthma/allergy and no asthma or allergy. Persons with asthma and multiple diagnoses reported odorous/pungent and building-related environmental factors to trigger symptoms to a larger extent than did the reference group, mainly due to perfume and odors from flowers. They also reported behavioral disruptions and affective reactions to odorous/pungent environments. These findings increase the understanding of the role of odorants in symptom development and thereby the prevention of health problems in asthma and allergy in indoor air.

Childhood asthma prevalence and risk factors in three Eastern European countries--the Belarus, Ukraine, Poland Asthma Study (BUPAS): an international prevalence study

Background

The prevalence of asthma and other allergic diseases among children living in Eastern is not well described. Our objective was to estimate and compare the prevalence of asthma, respiratory symptoms and allergic diseases in children in Belarus, Ukraine, and Poland as well as to identify risk factors for these conditions. We also sought to profile and compare children with asthma between locations.

Methods

Data were collected as a part of an international, multicenter, cross-sectional study of childhood asthma: The Belarus Ukraine Poland Asthma Study (BUPAS). Subjects were children aged 7–13 years attending primary and secondary schools in the urban and surrounding rural area of Grodno (Belarus), Ternopil (Ukraine) and Silesia Region (Poland). Physician-diagnosed respiratory diseases and symptoms as well as allergic diseases were ascertained using the ISAAC questionnaire completed by the parents.

Results

In total there were 4019 children from Belarus (rural: 2018, urban: 2001), 4493 from Ukraine (1972; 2521), and 4036 from Poland (2002, 2034). The overall response rate was 76.7 %. Groups were similar in case of gender and age (p > 0.05). Almost all analyzed respiratory and allergic conditions differed significantly between countries including asthma [Poland (rural, urban): 3.5 %, 4.1 %; Ukraine: 1.4 %, 2.1 %; Belarus: 1.4 %, 1.5 %], spastic bronchitis (Poland: 2.7 %, 3.2 %; Ukraine: 7.5 %, 6.5 %; Belarus: 6.4 %, 7.9 %), and chest wheeze in the last year (Poland: 4.8 %, 5.2 %; Ukraine: 11.5 %, 13.0 %; Belarus: 10.7 %, 10.0 %). These differences remained after adjustment for potential confounders. Risk factor associations were generally similar between outcomes. Symptom characteristics of children with asthma between countries were not consistent. The ratio of current wheeze:diagnosis of asthma differed by country: (Rural areas: Belarus: 10.9:1, Ukraine: 17.3:1, Poland: 2.4:1; Urban areas: Belarus: 8.1:1, Ukraine: 7.3:1 Poland: 1.9:1).

Conclusions

The findings show large between-country differences and relatively low prevalence of asthma and allergic diseases in children of Western Belarus and Ukraine. There is evidence for underdiagnosis of asthma in these regions.

Prevalence estimation of celiac disease in the general adult population of Latvia using serology and HLA genotyping

BACKGROUND

Prevalence estimates for celiac disease (CD) depend on the method used. The role of deamidated gliadin peptide (DGP) and genetic testing in epidemiological studies and diagnostic settings of celiac disease (CD) has still to be established.

OBJECTIVES

The objective of this article is to assess the prevalence of CD in Latvia by combining serological tests with DQ2.5/DQ8 testing.

METHODS

A total of 1444 adults from a randomly selected cross-sectional general population sample were tested by ELISA for tTG IgA, DGP IgA and IgG antibodies (QUANTA Lite®, Inova Diagnostics Inc). Samples with tTG IgA ≥20U were tested for EMA IgA by indirect immunofluorescence assay, and all specimens with tTG IgA ≥15U were tested by QUANTA-Flash® chemiluminescent assays (CIA) (Inova Diagnostics Inc) for tTG IgA, DGP IgA and IgG. DQ2.5/8 was detected in individuals with any positive ELISA test and a subgroup of controls.

RESULTS

Forty-three individuals (2.98%; 95% CI: 2.10-3.86%) tested positive by at least one ELISA test; 41.86% of the serology-positive individuals (any test above the cutoff) were DQ positive. Six individuals (0.42%; 95% CI: 0.09-0.75%) were triple ELISA positive, and DQ2.5 or DQ8 was positive in all; 0.35% (95% CI: 0.05-0.65%) were tTG IgA and EMA positive. Two tTG IgA-negative cases were both DGP IgG and IgA positive, both being DQ positive; including them in the "serology-positive" group would increase the prevalence to 0.49% (95% CI: 0.13-0.85%). CIA tests revealed 2 tTG IgA-positive and EMA-negative cases with a positive genotype. DQ2.5 or DQ8 genotype was positive in 28.6% of the serology-negative population.

CONCLUSIONS

Estimates of the prevalence of CD in Latvia based on the serogenetic testing approach range from 0.35% to 0.49% depending on the criteria used. There is a rationale for combining serological tests and DQ2.5/8 genotyping.

Operational definitions of asthma in recent epidemiological studies are inconsistent

OBJECTIVE

The best combination of questions to define asthma in epidemiological asthma studies is not known. We summarized the operational definitions of asthma used in prevalence studies and empirically assess how asthma prevalence estimates vary depending on the definition used.

METHODS

We searched the Thomson Reuters ISI Web of knowledge and included (1) cross-sectional studies (2) on asthma prevalence (3) conducted in the general population and (4) containing an explicit definition of asthma. The search was limited to the 100 most-cited papers or published since January 2010. For each paper, we recorded the asthma definition used and other variables. Then we applied the definitions to the data of the Portuguese National Asthma survey (INAsma) and of the 2005-2006 National Health and Nutrition Examination Survey (NHANES) computing asthma prevalence estimates for the different definitions.

RESULTS

Of 1738 papers retrieved, 117 were included for analysis. Lifetime asthma, diagnosed asthma and current asthma were defined in 8, 12 and 29 different ways, respectively. By applying definitions of current asthma on INAsma and NHANES data, the prevalence ranged between 5.3%-24.4% and 1.1%-17.2%, respectively.

CONCLUSIONS

There is considerable heterogeneity in the definitions of asthma used in epidemiological studies leading to highly variable estimates of asthma prevalence. Studies to inform a standardized operational definition are needed. Meanwhile, we propose a set of questions to be reported when defining asthma in epidemiological studies.

Early life exposure to antibiotics and the risk of childhood allergic diseases: an update from the perspective of the hygiene hypothesis

The prevalence of allergic diseases has been growing rapidly in industrial countries during recent decades. It is postulated that growing up with less microbial exposure may render the immune system susceptible to a T helper type 2 (Th2)-predominant allergic response-also known as the hygiene hypothesis. This review delineates recent epidemiological and experimental evidence for the hygiene hypothesis, and integrates this hypothesis into the association between early life exposure to antibiotics and the development of allergic diseases and asthma. Several retrospective or prospective epidemiological studies reveal that early exposure to antibiotics may be positively associated with the development of allergic diseases and asthma. However, the conclusion is inconsistent. Experimental studies show that antibiotics may induce the Th2-skewed response by suppressing the T helper type 1 (Th1) response through inhibition of Th1 cytokines and disruption of the natural course of infection, or by disturbing the microflora of the gastrointestinal (GI) tract and therefore jeopardizing the establishment of oral tolerance and regulatory T cell immune responses. The hygiene hypothesis may not be the only explanation for the rapid increase in the prevalence of allergic diseases and asthma. Further epidemiological and experimental studies addressing the issue of the impact of environmental factors on the development of allergic diseases and the underlying mechanisms may unveil novel strategies for the prevention and treatment of allergic diseases in the future.

The burden of allergic asthma in children: a landscape comparison based on data from Lithuanian, Latvian, and Taiwanese populations

Asthma is one of the most common chronic respiratory diseases with an increasing prevalence and financial burden worldwide. This disease affects individuals in all countries and all ethnic groups; however, prevalence rates of asthma have been reported to vary significantly between different regions. To understand the origin of asthma and to manage it effectively, it is necessary to analyze the genetic and environmental factors that cause these geographic differences. Therefore, we aimed to review published data from the investigations of asthma patients in Eastern Europe, represented by Latvia and Lithuania, and of patients from Eastern Asia represented by Taiwan. We hope that some of the common factors can be identified and different variants can be compared among these three countries for development of a new strategy to prevent childhood asthma.

Allergic diseases and respiratory symptoms in urban and rural children in Grodno Region (Belarus)

BACKGROUND

Because of the unknown frequency of asthma and other common allergic diseases in children living in Belarus, we conducted a population-based respiratory health survey. The objective of the study was to estimate the prevalence of allergic diseases and major allergic symptoms in children of the Grodno Region (Western Belarus) and to examine their familial and environmental correlates.

METHODS

The cross-sectional study was conducted in 2010 and included 2606 urban and 2422 rural children aged 6-16 years. Physician-diagnosed respiratory diseases and symptoms were ascertained using the ISAAC questionnaire completed by the parents. Both family and environmental factors were examined for their association with respiratory health outcomes including asthma and spastic bronchitis. Descriptive statistics and multiple logistic regression analysis were used to test associations.

RESULTS

The prevalence of asthma, atopic eczema and allergic rhinitis was 1.39%, 10.25%, and 3.84%, respectively. Spastic bronchitis was reported for 6.74% of children. Chronic respiratory symptoms occurring in the past 12 months and suggestive of asthma included chest wheeze (9.71%) attacks of dyspnea at rest (1.77%), symptoms of hay fever (2.45%) attacks of sneezing and nasal congestion without a cold (6.78%), and recurrent itchy rash (13.48%). All diseases except for asthma and spastic bronchitis as well as symptoms of hay fever, congested nose and itchy rash were more frequent in urban than in rural children (p < 0.05). Results of multivariate logistic analysis confirmed associations (p < 0.05) between asthma and parental asthma (OR = 4.82) and dampness in home (OR = 2.12) after adjustment for age, gender and place of residence. Spastic bronchitis in children who did not have a concurrent diagnosis of asthma was related (p < 0.05) to parental asthma (OR = 2.18), dampness in the home (OR = 1.68) and less use of coal-based heating (OR = 0.64). Allergic rhinitis and atopic eczema were associated (p < 0.05) with parental asthma (OR = 5.07 and OR = 1.91, respectively), dampness (OR = 2.33 and OR = 1.51, respectively), lower parental education (OR = 0.74 and OR = 0.68, respectively) and household density (OR = 0.84 and OR = 0.92), respectively.

CONCLUSIONS

The findings show a low prevalence of allergic diseases and symptoms in children of Western Belarus, following similar East-West gradients described in the literature. All allergic disorders except asthma were less frequent in the rural population. A very low prevalence of childhood asthma and the possibility of underdiagosis of the disease in the surveyed population deserve further investigation.

Diverse microbial exposure - consequences for vaccine development

Numerous epidemiological studies suggest that there is an inverse relationship between "immunologically mediated diseases of affluence", such as allergy, diabetes and inflammatory bowel disease on one hand and few infections encountered in early childhood, on the other hand. Careful analysis of the epidemiological, clinical and animal studies taken together, however, suggests that the protection is mediated by broad exposure to a wealth of commensal, non-pathogenic microorganisms early in life, rather than by infections. Microbial exposure has little relationship with "hygiene" in the usual meaning of the word and the term "hygiene hypothesis" is therefore misleading. A better term would be "microbial deprivation hypothesis". The suggestion that childhood infections would protect against allergic disease led to unfortunate speculations that vaccinations would increase the risk for allergies and diabetes. Numerous epidemiological studies have therefore been conducted, searching for a possible relationship between various childhood vaccinations on one hand and allergy on the other hand. It is reasonable from these studies to conclude that vaccinations against infectious agents neither significantly increase, nor reduce the likelihood of immunologically mediated diseases. It is established that the postnatal maturation of immune regulation is largely driven by exposure to microbes. Germ free animals manifest excessive immune responses when immunised and they do not develop normal immune regulatory function. The gut is by far the largest source of microbial exposure, as the human gut microbiome contains up to 1014 bacteria, i.e. ten times the number of cells in the human body. Several studies in recent years have shown differences in the composition of the gut microbiota between allergic and non-allergic individuals and between infants living in countries with a low and a high prevalence of immune mediated diseases. The administration of probiotic bacteria to pregnant mothers and postnatal to their infants has immune modulatory effects. So far, however, probiotic bacteria do not seem to significantly enhance immune responses to vaccines. The potential to improve vaccine responses by modifying the gut microbiota in infants and the possibility to employ probiotic bacteria as adjuvants and/or delivery vehicles, is currently explored in several laboratories. Although to date few clinical results have been reported, experimental studies have shown some encouraging results.

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.

Global analysis of breast feeding and risk of symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children: ISAAC Phase Three

BACKGROUND

In Phase Three of the International Study of Asthma and Allergies in Childhood (ISAAC), we investigated the relationship between breast feeding in infancy and symptoms of asthma, rhinoconjunctivitis and eczema in 6-7 year old children.

METHODS

Parents or guardians of 6-7 year old children completed written questionnaires on current symptoms of asthma, rhinoconjunctivitis and eczema, and on a range of possible asthma risk factors including a history of breast feeding ever. Prevalence odds ratios were estimated using logistic regression, adjusted for gender, region of the world, language, per capita gross national income, and other risk factors.

RESULTS

In all 206,453 children from 72 centres in 31 countries participated in the study. Reported breast feeding ever was not associated with current wheeze, with an odds ratio (adjusted for gender, region of the world, language, per capita gross national income, and factors encountered in infancy) of 0.99 (95% CI 0.92-1.05), current rhinoconjunctivitis (OR 1.00, 95% CI 0.93-1.08), current eczema (OR 1.05, 95% CI 0.97-1.12), or symptoms of severe asthma (OR 0.95, 95% CI 0.87-1.05). Breast feeding was however associated with a reduced risk of severe rhinoconjunctivitis (OR 0.74, 95% CI 0.59-0.94) and severe eczema (OR 0.79, 95% CI 0.66-0.95).

CONCLUSIONS

There was no consistent association between breast feeding use in the first year of life and either a history or current symptoms of wheezing, rhinoconjunctivitis or eczema in 6-7 year old children, but possibly an effect on severe symptoms of the latter two conditions.

Prevalence of childhood asthma and allergies in Serbia and Montenegro

BACKGROUND

This is the first multi-center epidemiological study on the prevalence of childhood asthma in Serbia and Montenegro. The International Study of Asthma and Allergies in Childhood (ISAAC) phase 3 is a large epidemiological multinational and multicentric study on the prevalence of asthma, allergic rhinitis and eczema in children.

METHODS

The 12-month period prevalence of asthma, allergic rhinitis and eczema was calculated using an ISAAC phase 3 questionnaire for two age groups: 6-7 years old and 13-14 years old.

RESULTS

In the 13 485 children from five study centers who responded to the questionnaire, the prevalence for childhood asthma ranged from 2.5% to 9.8%, for allergic rhinoconjunctivitis (hay fever) from 4.6% to 21%, and for eczema from 8.2% to 17.2%. The prevalence of current wheezing was high in both age groups (16.5% and 12.4% respectively).

CONCLUSIONS

The prevalence of asthma is higher in 6-7 years old school children in the urban and largest cities of Belgrade and Nis, and in 13-14 years old children in Podgorica. The prevalence of asthma, allergic rhinitis and eczema in the school children of Serbia and Montenegro seems similar to that of other countries in Central and South-Eastern Europe.

Burden of skin diseases

Skin diseases are among the most common health problems worldwide and are associated with a considerable burden. The burden of skin disease is a multidimensional concept that encompasses psychological, social and financial consequences of the skin disease on the patients, their families and on society. Chronic and incurable skin diseases, such as psoriasis and eczema, are associated with significant morbidity in the form of physical discomfort and impairment of patients' quality of life; whereas malignant diseases, such as malignant melanoma, carry substantial mortality. With the availability of a wide range of health status and quality-of-life measures, the effects of most skin diseases on patients' lives can be measured efficiently. The aim of this review is to present some of the published data in order to highlight the magnitude of the burden associated with some common skin diseases and also to suggest ways to quantify this burden of skin disease.

Effect of degree of urbanisation on age and sex-specific asthma prevalence in Swedish preschool children

Background

There are few studies on age and sex-specific asthma prevalence in the age range 1–6 years. The purpose of this report was to estimate age and sex specific asthma prevalence in preschool children and to analyse the influence of possible demographic and geographic determinants.

Methods

All 70 allergen avoidance day-care centres and 140 matched ordinary day-care centres across Sweden were sampled. The parents of all 8,757 children attending these day-care centres received the International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire, supplemented with questions on medical treatment, physician assessed asthma diagnosis, and other asthma related questions. The response rate was 68%.

Results

The age specific asthma prevalence, adjusted for the underlying municipality population size, was among boys 9.7% at age 1, 11.1% at age 2, 11.4 at age 3, 10.5 at age 4, 8.7 at age 5, and 6.4 at age 6. The corresponding proportions among girls were 8.9%, 9.9%, 9.8%, 8.8%, 7.0%, and 5.0%, on average 9.6% for boys and 8.2% for girls, altogether 8.9%. In addition to age and sex the prevalence increased by municipality population density, a proxy for degree of urbanisation. Moreover, there was a remaining weak geographical gradient with increasing prevalence towards the north and the west.

Conclusion

The age-specific asthma prevalence was curvilinear with a peak around age 3 and somewhat higher for boys than for girls. The asthma prevalence increased in a slowly accelerating pace by municipality population density as a proxy for degree of urbanisation.

Analysis of airborne betula pollen in Finland; a 31-year perspective

In this 31-year retrospective study, we examined the influence of meteorology on airborne Betula spp. (birch) pollen concentrations in Turku, Finland. The seasonal incidence of airborne birch pollen in Turku occurred over a brief period each year during spring (April 30 – May 31). Mean peak concentrations were restricted to May (May 5 to 13). Statistically significant increases in the annual accumulated birch pollen sum and daily maximum values were observed over the study period. Birch pollen counts collected in April were retrospectively shown to increase over the duration of the study. Increases in April temperature values were also significantly associated with the earlier onset of the birch pollen season. Furthermore, the number of days where daily birch pollen concentrations exceeded 10 and 1,000 grains/m³ also increased throughout the study period. These data demonstrate that increases in temperature, especially during months preceding the onset of the birch pollen season, favor preseason phenological development and pollen dispersal. Birch pollen derived from other geographical locations may also contribute to the aerospora of Turku, Finland. To date, the public health burden associated with personal exposure to elevated birch pollen loads remains unclear and is the focus of future epidemiological research.

The low prevalence of allergic disease in Eastern Europe: are risk factors consistent with the hygiene hypothesis?

BACKGROUND

The prevalence of allergic disease is known to be low in Eastern Europe.

OBJECTIVE

To assess the association of suspected risk factors, including several closely linked to the hygiene hypothesis, with allergic symptoms and atopic sensitization in young school-aged children.

METHODS

Observational study of 13 889 Belarusian children followed up at age 6.5 years in the Promotion of Breastfeeding Intervention Trial (PROBIT). Allergic symptoms and diseases were based on parental responses to the International Study of Asthma and Allergy in Childhood questionnaire, and prick tests to five common inhalant allergens were performed using standard methods.

RESULTS

Significantly increased risks of wheezing and hayfever symptoms in the past 12 months, and of recurrent itchy rash were observed in boys, children with a positive first-degree family atopic history, and those who had received probiotics (especially as prophylaxis with antibiotic use). Pet ownership, contact with farm animals, the presence and number of younger and (especially) older siblings, and residency in rural areas of Western Belarus were associated with reduced risks. Maternal postnatal smoking was associated with wheezing and hayfever symptoms, while the duration of exclusive breastfeeding was not protective against any of the studied outcomes. The risk factors for allergic symptoms were similar in children with positive skin-prick tests to those in the overall cohort.

CONCLUSION

Many of the risk and protective factors we identified are consistent with those reported in Western countries and with the hygiene hypothesis. Further research on dietary and other environmental and genetic factors is necessary to understand the low prevalence of allergic disease in Belarus and other Eastern European countries.

[Atopy and asthma]

Numerous studies have shown an association between the development of allergic sensitization and asthma. On the population level the strength of this association is variable and depends on the gross national income (GNI) of a country. The higher the GNI is, the stronger is the association between atopy and asthma. The development of a perennial sensitization to indoor allergens such as house dust mites, cat and dog plays is a strong risk factor for a chronic asthma course over childhood years. Likewise, a strong sensitization to perennial allergens in adolescence contributes to asthma progression over puberty. Therefore, early and repeated allergy tests are warranted since they are predictors of the prognosis of these patients.

Is the prevalence of asthma and related symptoms among Brazilian children related to socioeconomic status?

OBJECTIVE

To evaluate the relationship between socioeconomic status (SES) and the prevalence of asthma and related symptoms among Brazilian children.

METHODS

The International Study of Asthma and Allergies in Childhood (ISAAC) written questionnaire was applied to 23,457 six- to seven-year-old schoolchildren (SC) and 58,144 thirteen- to fourteen-year-old adolescents (AD) from 20 Brazilian cities. SES was evaluated by infant mortality index, poverty index, and average nominal income for people older than 10 years of age.

RESULTS

Current asthma ranged from 16.5% to 31.2% among SC and from 11.8% to 30.5% among AD and severe asthma from 2.9% to 8.5% (SC) and 2.6% to 9.1% (AD). Higher values were observed in Brazilian-Northern, -Northeastern and -Southeastern centers. No significant association between SES and prevalence of asthma and related symptoms was observed.

CONCLUSIONS

In Brazil, the prevalence of asthma and related symptoms is quite variable and independent of SES.

Worldwide time trends for symptoms of rhinitis and conjunctivitis: Phase III of the International Study of Asthma and Allergies in Childhood

In Phase III of the International Study of Asthma and Allergies in Childhood (ISAAC) time trends in the prevalence of rhinoconjunctivitis symptoms were analysed. Cross-sectional questionnaire surveys with identical protocols and questionnaires were completed a mean of 7 yr apart in two age groups comprising 498,083 children. In the 13- to 14-yr age group 106 centres in 56 countries participated, and in the 6- to 7-yr age group 66 centres in 37 countries participated. A slight worldwide increase in rhinoconjunctivitis prevalence was observed, but the variations were large among the centres and there was no consistent regional pattern. Prevalence increases in the older children exceeding 1% per year were recorded in 13 centres, including 3 of 9 centres in Africa, 2 of 15 in Asia-Pacific, 1 of 8 in India, 3 of 15 in Latin America, 3 of 9 in Eastern Europe and 1 of 34 in Western and Northern Europe. Decreasing rhinoconjunctivititis prevalence of similar magnitude was only seen in four centres. The changes were less pronounced in the 6- to 7-yr-old children and only in one centre did any change exceed 1% per year. The decrease in highest prevalence rates in ISAAC Phase I suggests that the prevalence has peaked in those regions. An increase was recorded in several centres, mostly in low and mid-income countries. The increases were more pronounced in the older age group, suggesting that environmental influences on the development of allergy may not be limited to early childhood.

Comparison of allergic diseases, symptoms and respiratory infections between Finnish and Russian school children

BACKGROUND

Little is known about differences in allergic and respiratory diseases between the Finnish and Russian populations.

METHODS

We conducted a population-based cross-sectional study to compare the occurrence of allergic diseases and respiratory infections among school children in the towns of Imatra in Finland and Svetogorsk in Russia on either side of the common border. The study population consisted of 512 Finnish and 581 Russian school children aged 7-16 years (response rate 79%). We used multiple logistic regression analysis to calculate odds ratios adjusting for age and gender.

RESULTS

The prevalences of asthma (6.7 vs. 3.9%, adjusted odds ratio (OR) 1.54, 95% confidence interval (CI 0.87-2.71), allergic rhinitis (15.2 vs. 8.8%, OR 1.81, 1.22-2.68), allergic conjunctivitis (4.7 vs. 3.2%, 1.33, 0.70-2.53), and atopic dermatitis (10.5 vs. 5.9%, 1.78, 1.12-2.83) were substantially higher among school children in Imatra compared to those in Svetogorsk, but the symptoms were more severe among allergic Russian children. Tonsillitis (adjusted OR 0.11, 95% CI 0.07-0.17), sinusitis (0.39, 0.24-0.63), bronchitis (0.41, 0.27-0.62) and pneumonia (0.19, 0.04-0.90) occurred less frequently in the Finnish children, whereas otitis media (2.37, 1.55-3.62) and common cold (4.07, 3.12-5.31) were more frequent in Finland.

CONCLUSIONS

Allergic diseases are more common in Finnish than Russian school children, but the symptoms are more severe among allergic Russian children. Respiratory infections are in general more frequent in Russian children. "Western" lifestyle habits, differences in diagnostic procedures and environmental factors, and availability of health care and medications are discussed as possible explanations for the observed differences.

Prevalence of symptoms of asthma, rhinitis, and atopic eczema among adolescents living in urban and rural areas in different regions of Brazil

BACKGROUND

In Brazil, studies evaluating the prevalence of asthma and allergic diseases among children living in rural area compared to urban area are rare. Some authors identified as risk factors for higher prevalence of current wheezing to have a family history of asthma, to have contact with pets, and being student in an urban school. The International Study of Asthma and Allergies in Childhood (ISAAC) phase 3 has shown higher prevalence of wheezing, nasal symptoms and cutaneous rash in the last 12 months in centers from Northern (N) and Northeastern (NE) regions of Brazil.

OBJECTIVE

To evaluate if adolescents with similar genetic background, living in a rural area are protected against the development of symptoms of asthma, rhinitis, and atopic eczema when compared to those living in an urban area in the same region of the country.

SUBJECTS AND METHOD

Adolescents (13-14 year-old) living in Caruaru (Pernambuco) and in Santa Maria (Rio Grande do Sul) were enrolled in this study (2002-2003). The adolescents filled in the ISAAC written questionnaire (WQ), previously translated and validated to the Brazilian culture (30-32). Data obtained were transcribed manually into a database (Epi-Info) supplied by ISAAC's coordinators and were statistically analyzed by the SSPS-12 software.

RESULTS

The prevalence of asthma related symptoms were higher among those adolescents living in the urban centers in comparison to the rural ones. These differences were significant for wheezy ever, wheezy in the last 12 months, asthma ever, and wheezy with exercise in Caruaru and for wheezy ever and asthma ever, in Santa Maria. Comparing urban areas, the prevalence of asthma related symptoms in Caruaru was higher than in Santa Maria, except for wheezy ever and wheezy with exercise. The opposite was observed comparing rural areas: the prevalence of asthma (except for nocturnal cough) was higher in Santa Maria despite lesser severity of symptoms in this city.

Bacille-Calmette-Guerin vaccination and the development of allergic disease in children: a randomized, prospective, single-blind study

BACKGROUND

The increase in the prevalence of allergic diseases in countries with a so-called western lifestyle may be due to a decrease in exposure to infectious agents in early life.

OBJECTIVE

To establish the effect of Bacille-Calmette-Guerin (BCG) vaccination in 6-week-old high-risk infants in a prospective single-blind, randomized, placebo-controlled trial on the prevalence of allergic disease at the age of 4 and 18 months.

METHODS

Subjects were 121 predominantly Caucasian high-risk newborns, having either a mother, or both a father and at least one sibling with past or present allergic disease. BCG or placebo was administered at the age of 6 weeks, and repeated once when both a post-vaccination scar and a positive TB skin test were absent at the age of 4 months.

RESULTS

At the age of 18 months, the prevalence of allergic disease was not significantly different between the two groups. A trend towards less eczema (P=0.07) and significantly less use of medication for eczema was shown in the BCG group compared with the placebo group (P=0.04).

CONCLUSION

A single (or once repeated) BCG vaccination in 6-week-old high-risk Caucasian infants was not associated with a 50% reduction in the prevalence of allergic disease. However, there could be a smaller beneficial effect of BCG, especially because a trend towards less eczema and significantly less use of medication for eczema was shown. For definite proof, a larger study should be carried out.

Association between children's household living conditions and eczema in the Polokwane area, South Africa

The aim of the study was to determine the 12-month prevalence of eczema symptoms (ES), the prevalence of ever having had eczema (EE), and potential risk factors among 6-7-year-old children within a 60km radius of Polokwane city centre, Limpopo Province, South Africa. This study applied the International Study of Asthma and Allergies in Childhood (ISAAC) Phase III protocol. It was conducted during August 2004 (winter) and February 2005 (summer). Among the 2437 participants, the 12-month prevalence of ES (17%) was much lower than the prevalence of EE (38%). The multivariate logistic regression model revealed that the likelihood of having ES was significantly increased by 43% in rural areas, and by 54% when exposed to environmental tobacco smoke (ETS) at home. The model also revealed that the likelihood of EE significantly increased with ETS exposure at home (37%), and by the use of coal, paraffin, gas and/or electricity for cooking (28%). Living in a formal house significantly decreased the likelihood of EE by 23%. Eczema appears to be a substantial public health problem in the Polokwane area. It is hoped that future studies will scrutinize these results in more detail, to inform and influence policy decisions, and form a basis for a health-promotion intervention in the community.

[Prevalence of asthma and rhinitis symptoms in A Coruña (Spain)]

INTRODUCTION

The prevalence of asthma and rhinitis is high in childhood and has been increasing in the last few years. In both diseases underdiagnosis is frequent.

OBJECTIVE

To asses the prevalence of asthma and rhinitis symptoms in childhood.

MATERIAL AND METHODS

We performed a cross-sectional study using a written questionnaire, following the methodology of the International Study of Asthma and Allergies in Childhood (ISAAC), on the prevalence of symptoms of asthma and rhinitis in La Coruña.

RESULTS

A total of 3017 boys and girls aged 6-7 years old (response rate 73.9 %) and 2981 boys and girls aged 13-14 years old (response rate 93.6 %) were included. The prevalence of "wheezing at some time" was 25.3 % in adolescents aged 13-14 years old and was 37.2 % in children aged 6-7 years. The prevalence of "asthma at some time" was 18.5 % in adolescents and 13.7 % in children. The prevalence of "rhinitis at some time" was 30.4 % in the group aged 6-7 years and 47.3 % in the group of adolescents. The prevalence of rhinitis was highest in autumn.

CONCLUSIONS

The prevalence of asthma and rhinitis is high in our population and is higher than that observed in most Spanish populations studied.

Aims, methods and preliminary findings of the Physical Activity, Nutrition and Allergies in Children Examined in Athens (PANACEA) epidemiological study

BACKGROUND

To determine the prevalence of asthma symptoms in a sample of Greek children aged 10-12 years, and to evaluate these rates in relation to anthropometric, lifestyle characteristics and dietary habits.

METHODS

During 2006, 700 schoolchildren (323 male and 377 female), aged 10-12 years (4th to 6th school grade), were selected from 18 schools located in the greater Athens area. The schools were randomly selected from a list provided by the regional educational offices. To achieve a representative sample the schools enrolled were selected from various region of the Athens area. For each child a questionnaire was completed that was developed for the purposes of the study to retrieve information on: age, sex, school class, other socio-demographic characteristics, anthropometric measurements, dietary habits (through a semi-quantitative Food Frequency Questionnaire) and physical activity status; the presence of asthma and allergies was assessed by the standard ISAAC questionnaire.

RESULTS

The prevalence of wheezing in the past was 25% in boys and 19% in girls, while the prevalence of current wheezing was 9.0% in boys and 5.8% in girls. The prevalence of any asthma symptoms was 27.6% in boys and 20.4% in girls. Multiple logistic regression analysis revealed that increased body weight and sedentary lifestyle is associated with asthma symptoms only in boys.

CONCLUSION

The present cross-sectional study cannot establish causal relationships between asthma and increased body weight of schoolchildren; however, our findings underline the associations between asthma, increased body weight, and physical activity at population level, and urge for actions that should be taken by public health policy makers in order to prevent these conditions among children.

Atopic dermatitis in adolescent boys is associated with greater psychological morbidity compared with girls of the same age: the Young-HUNT study

BACKGROUND

Having atopic dermatitis (AD) as well as other chronic diseases is often associated with reduced mental health. Adolescents with AD are thought to be especially vulnerable, but few studies have included an ample number of young people.

OBJECTIVES

To study self-reported mental distress among boys and girls 13-19 years of age with AD compared with mental distress among healthy adolescents as well as mental distress among adolescents with other chronic diseases or complaints, such as headache, neck or shoulder pain, asthma, allergy and rhinitis.

METHODS

The Young-HUNT study was conducted as a cross-sectional, population-based survey in 1995-97. All students in Nord-Trondelag County, Norway, aged 13-19 years were invited, and some 89% participated. A questionnaire on mental and somatic health, life-style and social conditions was completed during one school hour.

RESULTS

A total of 4384 girls and 4433 boys participated. The prevalence of mental distress was higher among older teenagers, and more than every fourth girl aged 17-19 reported mental distress. Although more girls than boys reported mental distress, AD, headache and neck or shoulder pain, the odds for reporting both AD and mental distress were higher for boys [odds ratio (OR) = 2.1 (1.6-2.9)] compared with girls [OR = 1.3 (1.1-1.6)]. A corresponding sex difference in reporting mental distress was also seen for some other chronic diseases or complaints.

CONCLUSIONS

In adolescents aged 13-19 years there was a strong and significant association between self-reported mental distress and AD as well as headache and neck or shoulder pain for both sexes. Although boys reported fewer complaints as AD, they perceived the complaints a heavier burden than did the girls.

Allergic sensitization and microbial load--a comparison between Finland and Russian Karelia

Epidemiological data have indicated that some infections are associated with a low risk of allergic diseases, thus supporting the idea (hygiene hypothesis) that the microbial load is an important environmental factor conferring protection against the development of allergies. We set out to test the hygiene hypothesis in a unique epidemiological setting in two socio-economically and culturally markedly different, although genetically related, populations living in geographically adjacent areas. The study cohorts included 266 schoolchildren from the Karelian Republic in Russia and 266 schoolchildren from Finland. The levels of total IgE and allergen-specific IgE for birch, cat and egg albumen were measured. Microbial antibodies were analysed against enteroviruses (coxsackievirus B4), hepatitis A virus, Helicobacter pylori and Toxoplasma gondii. Although total IgE level was higher in Russian Karelian children compared to their Finnish peers, the prevalence of allergen-specific IgE was lower among Russian Karelian children. The prevalence of microbial antibodies was, in turn, significantly more frequent in the Karelian children, reflecting the conspicuous difference in socio-economic background factors. Microbial infections were associated with lower risk of allergic sensitization in Russian Karelian children, enterovirus showing the strongest protective effect in a multivariate model. The present findings support the idea that exposure to certain infections, particularly in childhood, may protect from the development of atopy. Enterovirus infections represent a new candidate to the list of markers of such a protective environment. However, possible causal relationship needs to be confirmed in further studies.

Skin sensitization in school children in northern and southern Norway

It has been suggested that environmental exposures and living conditions can explain some of the worldwide variation in atopic disorders. Norway has large environmental contrasts within the country. We compared skin prick sensitization rates among school children living in the southern subarctic and in the northern arctic part of Norway. Approximately one quarter of the children were sensitized, mostly against pollen and animal dander, while mite and mould sensitization seemed to be a minor problem. Sensitization rates and profiles were similar in the north and south despite differences in living conditions and environmental exposures.