The prevalences of allergic diseases in rural and urban areas are similar

Investigation of the presence of atopy in children visiting the paediatric cardiology department due to chest pain

BACKGROUND

The cases of chest pain in children are usually not of cardiac origin.

OBJECTIVES

To investigate asthma and other atopic diseases in children with chest pain not of cardiac origin.

PATIENTS AND METHODS

Children aged 6-18 years who were seen for chest pain were included in the study. Haematologic parameters, pulmonary function tests, and skin prick tests were performed. Atopic diseases and environmental factors were investigated.

RESULTS

The non-cardiac chest pain group (Group 1) included 88 children (female: 53.4%) with a mean age of 11.9 ± 3.4 years; the control group (Group 2) included 29 children (female: 53.8%) with a mean age of 11.4±2 years (p > 0.05). A family history of atopy (22.7%) and skin prick test positivity (28.4%) was more common in Group 1 than Group 2 (p = 0.006 and p = 0.017, respectively). The rate of presence of all environmental factors except stove use and mould was significantly higher in Group 1 (54.5%) than Group 2 (3.4%) (p < 0.001). Asthma was diagnosed in 44.3% and allergic rhinitis in 9.1% of patients in Group 1. Idiopathic chest pain, musculoskeletal system disorders, gastroesophageal reflux, and pneumonia were identified in 23.9%, 11.4%, 8%, and 3.4% of patients in Group 1, respectively.

CONCLUSIONS

In this study, the most common cause of non-cardiac chest pain was asthma. The local prevalence of asthma is higher than normal, and this may have affected the results of this study. A detailed history and physical examination will accurately establish the cause of chest pain in most children.

Geographische Unterschiede zwischen städtischem und ländlichem Raum beim Risiko für atopische Dermatitis: Systematischer Review und Meta-Analyse

Die atopische Dermatitis ist die häufigste chronisch‐entzündliche Hauterkrankung im Kindesalter. Einige Studien kamen zu dem Ergebnis, das Risiko für diese Erkrankung sei im städtischen Raum höher als im ländlichen. Wir haben die verfügbaren Studien systematisch untersucht und eine Meta‐Analyse durchgeführt, um Unterschiede im Risiko für atopische Dermatitis zwischen städtischem und ländlichem Raum zu erkennen. Die Suche in den Datenbanken Embase und MEDLINE wurde am 19. April 2021 durchgeführt. Einschlusskriterium war das Stichwort “Beobachtungsstudie”. Wir haben außerdem Subgruppenanalysen bezüglich Patientenalter, Publikationsjahr und Land durchgeführt. Insgesamt wurden bei der Datenbanksuche 2115 Studien aufgefunden, von denen letztlich 43 Studien mit insgesamt 1 728 855 Patienten in die Meta‐Analyse eingeschlossen wurden. Ein Wohnsitz im städtischen Raum war mit einem erhöhten Risiko für atopische Dermatitis assoziiert; die Odds Ratio war 1,56 (95 %‐Konfidenzintervall 1,43–1,71). Dieses signifikant erhöhte Risiko war nur bei Kindern zu beobachten (Odds Ratio 1,55, 95 %‐Konfidenzintervall 1,39–1,73), nicht jedoch bei Erwachsenen. Hier betrug die Odds Ratio 1,29 (95 %‐Konfidenzintervall 0,99–1,67). Das Risiko für atopische Dermatitis ist in den letzten Jahrzehnten angestiegen, wobei das Risiko in Entwicklungsländern mit einer Odds Ratio von 1,95 höher liegt als in Industrieländern (Odds Ratio 1,35). Unsere Studie bestätigt die Assoziation zwischen atopischer Dermatitis und dem Wohnsitz im städtischen gegenüber dem ländlichen Raum.

Geographic differences in atopic dermatitis risk between urban and rural area: A systematic review and meta-analysis

Atopic dermatitis is the most common chronic inflammatory skin disease affecting children. Some studies have reported a higher risk of atopic dermatitis in urban areas than in rural areas. We systematically reviewed and carried out a meta-analysis to investigate the differences in the development of atopic dermatitis between urban and rural areas. The search was performed on April 19, 2021, using Embase and MEDLINE databases. Eligible for inclusion were observational studies. Subgroup analyses were performed for age, publication year, and country. We identified 2,115 studies, and 43 studies with 1,728,855 subjects were finally included. Urban residency was associated with an increased risk of atopic dermatitis, with an odds ratio of 1.56 (95% confidence interval, 1.43-1.71). A significantly increased risk was observed only in children, with an odds ratio of 1.55 (95% confidence interval, 1.39-1.73), but not in adults, with an odds ratio of 1.29 (95% confidence interval, 0.99-1.67). The risk has increased in recent decades, with a higher risk in developing countries (odds ratio, 1.95) compared to developed countries (odds ratio, 1.35). Our study provides evidence of an association between atopic dermatitis and urban compared to rural living.

Allergic rhinitis in India

India is the home of nearly 20% of the global population with 1.35 billion people. Of all non-communicable diseases, allergic diseases such as allergic rhinitis (AR) and asthma appear to have increased in India over the past decades. Approximately 22% of adolescents currently suffer from AR in India. However, owing to the lack of adequate epidemiological studies in India, particularly in rural and suburban areas, this number may misrepresent the true burden of this disease. While the risk factors for AR are mainly environmental exposures or genetic factors, several new environmental, social, and behavioural risk factors such as the presence of dumpsters near residences, movement of vehicles near homes, and exposure to artificial light at night have been found to be associated with AR. However, despite international guidelines, the diagnosis and management of AR in India are often suboptimal, for multiple reasons such as the lack of specialized training in allergy and immunology among Indian clinicians, the lack of diagnostic facilities, and the high cost of medications. This review aims at highlighting the current scenario of AR in India and how it differs from the rest of the world. It also highlights the need for developing a strategic approach to enhance the quality of care for allergic diseases by upgrading education and training for healthcare professionals, creating awareness among clinicians and patients, and involving stakeholders and policymakers in making treatments accessible and affordable to patients.

Evaluation of orofacial dysfunctions and oral health-related quality of life in children with asthma

Objective: This study aimed to investigate the impact of asthma on oro-facial muscle dysfunction (OFD) and oral health-related quality of life (OHRQoL) in children. Materials and Method: A total of 158 children, 79 diagnosed with asthma and 79 healthy, were included in the study. Children diagnosed with asthma were divided into controlled and uncontrolled asthma groups. The OFD and OHRQoL of all participants were evaluated with Nordic Orofacial Test and Screening (NOT-S) and Child Perception Questionnaire (CPQ8-10). The differences and correlations between the groups were statistically evaluated (Mann-Whitney and Spearman and Chi-Square test). Results: NOT-S interview, examination, and total scores were statistically higher in the asthma group compared to healthy children and between uncontrolled and controlled asthma groups (p&lt;0.001). Higher scores were obtained in all areas of CPQ8-10 in the asthma group (p&lt;0.001). NOT-S and CPQ8-10 scores elevated compatibly in the groups diagnosed with asthma. Conclusion: OFD in asthmatic children predicts worse OHRQoL.

The prevalence and associated factors of asthma, allergic rhinitis, and eczema in Turkish children and adolescents

AIM

We aim to determine the prevalence and related risk factors of asthma and allergic diseases in school children and adolescent in Konya, Turkey, and to compare this prevalence with that of 11 years ago.

METHODS

This descriptive correlational study also includes the third phase of the International Study of Asthma and Allergies in Childhood protocol. A total of 2220 students aged between 6 and 18 took part in this study.

RESULTS

In our study, prevalence of wheezing of 21.8%, eczema of 4.3%, and allergic rhinitis of 43.2% were found in students until this age. In the study, student smoking, school location, history of asthma in the family, mold or moisture at home, and mother's smoking now were related factors for wheezing, while eating habits, breastfeeding, and student's gender were determined as related factors for allergic rhinitis symptoms in the past 12 months. In addition, having a pet, eating habits, and school level were determined as related factors for eczema symptoms in the past 12 months (p < 0.05). As a result of comparison of the findings of this study with the results of the study conducted by Güner et al., it was determined that the rates of wheezing and allergic rhinitis had increased, whereas the rate of eczema had decreased (p < 0.05).

CONCLUSION

It was determined that under the effect of urbanization in Konya, the prevalence of asthma and allergic rhinitis in students had increased, while the prevalence of eczema had decreased.

Association of regional socioeconomic deprivation and rurality with global developmental delay in early childhood: Data from mandatory school entry examinations in Germany

BACKGROUND

From birth to young adulthood, health and development of young people are strongly linked to their living situation, including their family's socioeconomic position (SEP) and living environment. The impact of regional characteristics on development in early childhood beyond family SEP has been rarely investigated. This study aimed to identify regional predictors of global developmental delay at school entry taking family SEP into consideration.

METHOD

We used representative, population-based data from mandatory school entry examinations of the German federal state of Brandenburg in 2018/2019 with n=22,801 preschool children. By applying binary multilevel models, we hierarchically analyzed the effect of regional deprivation defined by the German Index of Socioeconomic Deprivation (GISD) and rurality operationalized as inverted population density of the children's school district on global developmental delay (GDD) while adjusting for family SEP (low, medium and high).

RESULTS

Family SEP was significantly and strongly linked to GDD. Children with the highest family SEP showed a lower odds for GDD compared to a medium SEP (female: OR=4.26, male: OR=3.46) and low SEP (female: OR=16.58, male: OR=12.79). Furthermore, we discovered a smaller, but additional and independent effect of regional socioeconomic deprivation on GDD, with a higher odds for children from a more deprived school district (female: OR=1.35, male: OR=1.20). However, rurality did not show a significant link to GDD in preschool children beyond family SEP and regional deprivation.

CONCLUSION

Family SEP and regional deprivation are risk factors for child development and of particular interest to promote health of children in early childhood and over the life course.

Pro-inflammatory Diet Pictured in Children With Atopic Dermatitis or Food Allergy: Nutritional Data of the LiNA Cohort

Background

Lifestyle and environmental factors are known to contribute to allergic disease development, especially very early in life. However, the link between diet composition and allergic outcomes remains unclear.

Methods

In the present population-based cohort study we evaluated the dietary intake of 10-year-old children and analyses were performed with particular focus on atopic dermatitis or food allergy, allergic diseases known to be affected by dietary allergens. Dietary intake was assessed via semi-quantitative food frequency questionnaires. Based on these data, individual nutrient intake as well as children’s Dietary Inflammatory Index (C-DII™) scores were calculated. Information about atopic manifestations during the first 10 years of life and confounding factors were obtained from standardized questionnaires during pregnancy and annually thereafter.

Results

Analyses from confounder-adjusted logistic regression models (n = 211) revealed that having atopic outcomes was associated with having a pro-inflammatory pattern at the age of 10 years: OR = 2.22 (95% CI: 1.14–4.31) for children with atopic dermatitis and OR = 3.82 (95% CI: 1.47–9.93) for children with food allergy in the first 10 years of life.

Conclusion

A pro-inflammatory dietary pattern might worsen the atopic outcome and reduce the buffering capacity of the individual against harmful environmental exposures or triggers. For pediatricians it is recommended to test for the individual tolerance of allergenic foods and to increase the nutrient density of tolerable food items to avoid undesirable effects of eating a pro-inflammatory diet.

How does parental history of atopic disease predict the risk of atopic dermatitis in a child? A systematic review and meta-analysis

BACKGROUND

Parental history of atopic disease is a well-established risk factor for the development of atopic dermatitis (AD), but several aspects of this association remain unclear.

OBJECTIVE

We sought to determine the association of parental history of atopic disease with AD in offspring.

METHODS

We searched PubMed and EMBASE through June 2018 for relevant records and adhered to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. Pooled odds ratios (ORs) with 95% CI were calculated using random-effects models.

RESULTS

A total of 163 records covering 149 unique studies were included. Of these, 119 studies were included in the meta-analysis. Individuals with parental history of atopic disease had increased odds of AD (OR, 1.81; 95% CI, 1.65-1.99). Parental asthma (OR, 1.56; 95% CI, 1.18-2.05) and allergic rhinitis (OR, 1.68; 95% CI, 1.34-2.11) had a smaller effect than AD (OR, 3.30; 95% CI, 2.46-4.42). The effect of maternal and paternal history was comparable for all atopic diseases. An increase in odds was observed when comparing the effect of having 1 (OR, 1.30; 95% CI, 1.15-1.47) or 2 atopic parents (OR, 2.08; 95% CI, 1.83-2.36), as well as having a parent with 1 (OR, 1.49; 95% CI, 1.28-1.74) or more atopic diseases (OR, 2.32; 95% CI, 1.92-2.81).

CONCLUSIONS

This study provides evidence-based risk estimates that may guide physicians who counsel parents with a history of atopic disease about their children's risk of AD. This information is of particular importance for future efforts toward establishing prophylactic interventions for AD on a general population level.

The Correlation of Allergic Rhinitis with ABO Phenotype

The aim of study the correlation of ABO phenotypes in patients of allergic rhinitis and controls and to compare our study with the previous studies to analyse the association of above. 100 patients with symptoms of allergic rhinitis and 100 controls individual were selected from same geographical region and paired by gender and age were enrolled in the study. Detailed history, examination and relevant radiological and hematological investigations were done. ABO phenotypes were identified in red blood cells using hemagglutination technique. This clinic-based observational study was conducted among the patients presenting with signs and symptoms of allergic rhinitis. Maximum no. of cases were seen in ABO phenotype O (52%), followed by A, B and AB (33, 12 and 3% respectively) and it was found to be statistically significant (p = 0.001). Also more number of male patients were found in B and O blood group which was statistically significant (OR 5.33, p = 0.017 and OR 3.63, p = 0.006 respectively). Controls showed marginalized difference in distribution among the basis of different ABO phenotypes. The O blood group phenotype of ABO histo-blood group system is associated with AR. This study contributes to the better understanding of the pathophysiology and clinical variability of this disease and may help to improve strategies towards its prevention and diagnosis. Additionally, ABO histo-blood group phenotyping, an inexpensive and easy to perform assay could be used to identify individuals at risk of developing allergic rhinitis.

Urbanisation and asthma in low-income and middle-income countries: a systematic review of the urban-rural differences in asthma prevalence

BACKGROUND

Urbanisation has been associated with temporal and geographical differences in asthma prevalence in low-income and middle-income countries (LMICs). However, little is known of the mechanisms by which urbanisation and asthma are associated, perhaps explained by the methodological approaches used to assess the urbanisation-asthma relationship.

OBJECTIVE

This review evaluated how epidemiological studies have assessed the relationship between asthma and urbanisation in LMICs, and explored urban/rural differences in asthma prevalence.

METHODS

Asthma studies comparing urban/rural areas, comparing cities and examining intraurban variation were assessed for eligibility. Included publications were evaluated for methodological quality and pooled OR were calculated to indicate the risk of asthma in urban over rural areas.

RESULTS

Seventy articles were included in our analysis. Sixty-three compared asthma prevalence between urban and rural areas, five compared asthma prevalence between cities and two examined intraurban variation in asthma prevalence. Urban residence was associated with a higher prevalence of asthma, regardless of asthma definition: current-wheeze OR:1.46 (95% CI:1.22 to 1.74), doctor diagnosis OR:1.89 (95% CI:1.47 to 2.41), wheeze-ever OR:1.44 (95% CI:1.15 to 1.81), self-reported asthma OR:1.77 (95% CI:1.33 to 2.35), asthma questionnaire OR:1.52 (95% CI:1.06 to 2.16) and exercise challenge OR:1.96 (95% CI:1.32 to 2.91).

CONCLUSIONS

Most evidence for the relationship between urbanisation and asthma in LMICs comes from studies comparing urban and rural areas. These studies tend to show a greater prevalence of asthma in urban compared to rural populations. However, these studies have been unable to identify which specific characteristics of the urbanisation process may be responsible. An approach to understand how different dimensions of urbanisation, using contextual household and individual indicators, is needed for a better understanding of how urbanisation affects asthma.

PROSPERO REGISTRATION NUMBER

CRD42017064470.

A rural environment does not protect against asthma or other allergic diseases amongst Mexican children

INTRODUCTION

The commonly held notion that a rural environment decreases the frequency of allergic diseases has proven to be inconsistent amongst children.

OBJECTIVE

Our objective was to contrast the prevalence of bronchial asthma (BA), allergic rhinitis (AR), and atopic dermatitis (AD) between children that live in a rural environment and those that live in urban areas.

METHODS

We carried out a cross-sectional study amongst children aged six to seven; they were selected through probabilistic, stratified and conglomerated sampling. The prevalence of BA, AR, and AD was identified with the use of the questionnaire provided by The International Study of Asthma and Allergies in Childhood, additionally, we inquired about each child's family history of atopy, their exposure to farm animals, the intake of unpasteurised cow's milk, and the number of siblings related to every child. We used logistic regression and multivariate analysis to determine the correlation between asthma, allergic diseases, and rural environment.

RESULTS

We included 189/1003 (18.8%) children from a rural environment, and 814/1003 (81.2%) from an urban area. BA and AR were associated to a family history of atopy (OR=2.15, p=0.001; OR=2.58, p=0.002, respectively). BA was more prevalent in males (OR=1.92, p=0.007). Notably, a higher number of siblings seems to protect against AR (OR=0.45, p=0.008). A paternal history of allergies was associated to AD.

CONCLUSIONS

In our study, we were unable to find protective factors in a rural environment that might decrease the prevalence of asthma or allergic diseases.

The Prevalence of Allergic Rhinitis, Eczema and Asthma in Students of Guidance Schools in Mazandaran Province, Iran

BACKGROUND:

Eczema, allergic rhinitis and asthma are common chronic allergic disorders in childhood.

AIM:

The aim of this study was to determine the prevalence of common allergic disorders among Iranian guidance schools students in Mazandaran Province, northern Iran.

METHODS:

This analytical cross-sectional study was performed on 3000 children aged 11-14 years old during 2012-13 according to ISAAC study. Of 3000 recruited children 1576 (52.54%) were female and 1424 (47.46%) were male. Data gathered by ISAAC first phase questionnaire analysed by SPSS software 20.

RESULTS:

The prevalence of wheezing, allergic rhinitis symptoms (sneezing and pruritus) and atopic dermatitis symptoms (pruritus skin lesion) were 30.5%, 30% and 15% respectively. History of pets contact and smoking was positive 6.6% and 36 % respectively. About 52% was born with caesarian section. There was wheezing in 32.5% during sport. The diagnosis of asthma, allergic rhinitis and eczema were 12.2%, 28.5% and 15% respectively. Eczema, asthma and allergic rhinitis were significantly more common in boys students (p < 0.05).

CONCLUSIONS:

The results of this study showed that asthma, allergic rhinitis and eczema have a high prevalence and they are more common in boys.

Does urban extent from satellite images relate to symptoms of asthma, rhinoconjunctivitis and eczema in children? A cross-sectional study from ISAAC Phase Three

OBJECTIVE

The relationship between urbanisation and the symptom prevalence of asthma, rhinoconjunctivitis and eczema is not clear, and varying definitions of urban extent have been used. Furthermore, a global analysis has not been undertaken. This study aimed to determine whether the symptom prevalence of asthma, rhinoconjunctivitis and eczema in centres involved in the International Study of Asthma and Allergies in Childhood (ISAAC) were higher in urban than rural centres, using a definition of urban extent as land cover from satellite data.

METHODS

A global map of urban extent from satellite images (MOD500 map) was used to define the urban extent criterion. Maps from the ISAAC centres were digitised and merged with the MOD500 map to describe the urban percentage of each centre. We investigated the association between the symptom prevalence of asthma, rhinoconjunctivitis and eczema and the percentage of urban extent by centre.

RESULTS

A weak negative relationship was found between the percentage of urban extent of each ISAAC centre and current wheeze in the 13-14-year age group. This association was not statistically significant after adjusting for region of the world and gross national income. No other relationship was found between urban extent and symptoms of asthma, rhinoconjunctivitis and eczema.

CONCLUSIONS

In this study, the prevalence of symptoms of asthma, rhinoconjunctivitis and eczema in children were not associated with urbanisation, according to the land cover definition of urban extent from satellite data. Comparable standardised definitions of urbanisation need to be developed so that global comparisons can be made.

Urban-rural differences in asthma prevalence among young adolescents: The role of behavioural and environmental factors

BACKGROUND

Asthma prevalence has been reported to be lower in rural areas compared to urban areas, although this has been inconsistent. This study aims to identify the influence of urban-rural residence on asthma prevalence in adolescents in the Republic of Macedonia and to investigate characteristics that may explain observed associations.

METHODS

Following International Study of Asthma and Allergies in Childhood protocol, a national sample of Macedonian urban and rural dwelling adolescents (12-16 years) was recruited in 2006. Self-completed questionnaires were used to collect data on wheeze and asthma as well as personal, environmental and dietary characteristics. Following descriptive and multiple logistic regression analyses, a mediation analysis approach was performed to help explain observed associations.

RESULTS

A lower prevalence of current wheeze and ever-diagnosed asthma was observed in rural compared to urban dwelling adolescents (4.9% vs. 7.2% and 1.2% vs. 1.9%, respectively). After adjustment for potential confounders, the associations, although still protective, were not statistically significant (wheeze: OR=0.74, 95%CI=0.46-1.21; asthma: OR=0.97, 95%CI=0.38-2.46). The associations between urban-rural status with current wheeze and asthma were mediated by region of the country (wheeze 9%; asthma 19%) and by diet (>5% change for both wheeze and asthma). Having a dog resulted in a strengthening of the association between urban-rural status and current wheeze by 11.9%.

CONCLUSIONS

The prevalence of asthma and wheeze was lower in rural dwelling Macedonian adolescents and the association was mediated by the region of the country with diet likely to be part of the reason for this mediating effect.

Nasal and bronchial response to exercise in children with seasonal allergic rhinitis out of the pollen season

BACKGROUND

Allergic rhinitis is a type I allergic disease of the nasal mucosa, and is characterized by paroxysmal sneezing, watery rhinorrhea, and nasal blockage. In seasonal allergic rhinitis subjects, even subthreshold allergen doses have been found to cause inflammatory cell infiltration in the nasal mucosa. This study aimed to investigate the presence of nasal obstructions and symptoms in seasonal allergic rhinitis subjects by assessing an exercise challenge test (ECT) outside of the pollen season.

METHODS

Twenty patients and 20 healthy children who were admitted to the Osmangazi University Medical School Pediatric Allergy Clinic were included in the study in a pollen free season. The total nasal airflow and visual analog scale (for rhinorrhea, nasal congestion, sneezing, and itching) and pulmonary function tests were evaluated before and after each ECT. The nasal airflow and resistance changes were evaluated with anterior rhinomanometry.

RESULTS

Eight patients and one healthy child had nasal obstructions after the ECT. There was a significant difference in the exercise-induced nasal obstructions between the 2 groups (p = 0.02). Eighteen children with exposure to tobacco smoke in the patient and control groups had lower forced expiratory volume in 1 second (FEV1), forced vital capacity (FVC), and forced expiratory flow 25% to 75% (FEF25-75 ) values than the children without exposure to tobacco smoke.

CONCLUSION

The prevalence of exercise-induced nasal obstruction in children with seasonal rhinitis out of the pollen season is 40%. We showed that minimal persistent inflammation and nasal symptoms can also be diagnosed in rhinitis children in a symptom-free period.

Prevalence of allergic rhinitis among adults in urban and rural areas of china: a population-based cross-sectional survey

Purpose

The aim of the present study was to compare the prevalence of self-reported and confirmable allergic rhinitis (AR) with positive skin prick test (SPT) results among adults living in urban and rural areas of China.

Methods

Adults from a community in Beijing and a village in Baoding were selected as representative urban and rural dwellers, respectively. All eligible residents were enrolled from the population register and received a face-to-face interview using modified validated questionnaires. Equal sets of randomly selected self-reporting AR-positive and AR-negative participants who responded to the questionnaires were also investigated using skin prick tests.

Results

A total of 803 participants in the rural area and a total of 1,499 participants in the urban area completed the questionnaires, with response rates being 75.9% and 81.5% respectively. The prevalence of self-reported AR of the rural area (19.1%) was significantly higher than that of the urban area (13.5%). The elementary school of educational level increased the risk of having AR (adjusted OR=2.198, 95% CI=1.072-2.236) .The positive SPT rates among subjects with self-reported AR in the rural and urban areas were 32.5% and 53.3%, respectively; the confirmable AR prevalence of 6.2% and 7.2% among the rural and urban adults, respectively.

Conclusions

The prevalence of confirmable AR is similar between rural and urban areas in China, although there is a higher prevalence of self-reported AR in the former.

How are 'urban' and 'rural' defined in publications regarding asthma and related diseases?

BACKGROUND

Global variations in the prevalence of asthma and related diseases have suggested that environmental factors are causative, and that factors associated with urbanisation are of particular interest. A range of definitions for 'urban' and 'rural' have been used in articles on asthma and related diseases, making it difficult to assess their importance as aetiological factors. This study sets out to examine such definitions used in the literature.

METHODS

Medical and social science databases were searched for articles that made distinctions of 'urban' and/or 'rural' in the context of asthma and related diseases.

RESULTS

The search identified 73 articles and categorised four types of definitions. A specific definition of urban or rural was used in 19 (26%) articles. Nine (12%) articles used non-specific and/or administrative definitions. There were 23 (32%) articles that described locations as 'urban' or 'rural' but did not indicate if the description defined 'urban' or 'rural'. Distinctions were made between urban and rural locations without a description or definition in 22 (30%) articles.

CONCLUSIONS

There is substantial variation in the definitions of 'urban' and 'rural' in articles regarding asthma and related diseases. It would be advantageous to have clearer and more precise definitions of 'urban' and 'rural' which could facilitate aetiological research and also comparisons between locations, especially in international studies.

Maternal and newborn vitamin D status and its impact on food allergy development in the German LINA cohort study

BACKGROUND

Vitamin D levels are known to be associated with atopic disease development; however, existing data are controversial. The aim of this study was to investigate whether corresponding maternal and cord blood vitamin D levels are associated with atopic outcomes in early infancy.

METHODS

Within the LINA cohort study (Lifestyle and environmental factors and their Influence on Newborns Allergy risk), 25(OH)D was measured in blood samples of 378 mother-child pairs during pregnancy and at birth. Information about children's atopic manifestations during the first 2 years of life was obtained from questionnaires filled out by the parents during pregnancy and annually thereafter. Cord blood regulatory T cells (Treg) were detected by methylation-specific PCR using a Treg-specific demethylated region in the FOXP3 gene.

RESULTS

The median maternal 25(OH)D(3) level was 22.19 ng/ml (IQR 14.40-31.19 ng/ml); the median cord blood 25(OH)D(3) 10.95 ng/ml (6.99-17.39 ng/ml). A high correlation was seen between maternal and cord blood 25(OH)D(3) levels, both showing a seasonal distribution. Maternal and cord blood 25(OH)D(3) was positively associated with children's risk for food allergy within the first 2 years. Further, higher maternal 25(OH)D(3) resulted in a higher risk for sensitization against food allergens at the age of two. Cord blood 25(OH)D(3) levels were negatively correlated with regulatory T cell numbers.

CONCLUSION

Our study demonstrates that high vitamin D levels in pregnancy and at birth may contribute to a higher risk for food allergy and therefore argues against vitamin D supplement to protect against allergy.

The LINA cohort: indoor chemical exposure, circulating eosinophil/basophil (Eo/B) progenitors and early life skin manifestations

BACKGROUND

Hematopoietic progenitor cells, especially those committed to the Eo/B lineage, are known to contribute to allergic inflammation.

OBJECTIVE

The aim of the present study was to investigate whether environmental factors are associated with changes in numbers of circulating Eo/B progenitors at 1 year of age.

METHODS

Peripheral blood from 60 1-year-old children enrolled in the LINA (Lifestyle and environmental factors and their Influence on Newborns Allergy risk) birth cohort was assessed for Eo/B progenitor cells (Eo/B CFU) using standardized and validated methylcellulose assays. Frozen peripheral blood mononuclear cells (PBMC) were cultured in the presence of IL-3, IL-5 or GM-CSF, and Eo/B CFUs enumerated. Clinical outcomes and exposure to environmental tobacco smoke (ETS) were documented by standardized questionnaires, and indoor volatile organic compound (VOC) concentrations were assessed by passive sampling.

RESULTS

Children with skin manifestations (atopic dermatitis or cradle cap) within the first year of life had higher numbers of circulating IL-3-, IL-5- or GM-CSF-stimulated Eo/B CFUs (P < 0.05) at 1 year. In children with cradle cap, a positive correlation was found between Eo/B CFUs and exposure to ETS-related VOCs during pregnancy or at 1 year of age (P < 0.05).

CONCLUSIONS AND CLINICAL RELEVANCE

This is the first demonstration that environmental exposures are positively associated with levels of circulating Eo/B progenitors. The recruitment and differentiation of Eo/B progenitors in response to environmental triggers may play a role in the development of skin manifestations during the first year of life.