1,720,976 research outputs found
Dampness and moulds in relation to respiratory and allergic symptoms in children : results from phase two of the International Study of Asthma and Allergies in Childhood, (ISAAC Phase Two)
Full text linkMany studies report that damp housing conditions are associated with respiratory symptoms. Less is known about mechanisms and possible effect modifiers. Studies of dampness in relation to allergic sensitization and eczema are scarce.
Objective We study the influence of damp housing conditions world-wide on symptoms
and objective outcomes.
Cross-sectional studies of 8–12-year-old children in 20 countries used standardized
methodology from Phase Two of the International Study of Asthma and Allergies in
Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure
to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin
examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge
(n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled
and analysed for house dust mite (HDM) allergens and endotoxin.
Current exposure to dampness was more common for wheezy children (pooled
odds ratio 1.58, 95% CI 1.40–1.79) and was associated with greater symptom severity
among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness
was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined
eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in
damp homes (OR 1.16, 1.03–1.32). HDM-allergen levels were higher in damp homes and
were positively associated with HDM-sensitization, but not wheeze.
A consistent association of dampness with respiratory and other symptoms
was found in both affluent and non-affluent countries, among both atopic and non-atopic
children. HDM exposure and sensitization may contribute, but the link seems to be related
principally to non-atopic mechanisms.peer-reviewe
Can environment or allergy explain international variation in prevalence of wheeze in childhood?
Full text linkAsthma prevalence in children varies substantially around the world, but the contribution of known risk factors to this international variation is uncertain. The International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two studied 8-12 year old children in 30 centres worldwide with parent-completed symptom and risk factor questionnaires and aeroallergen skin prick testing. We used multilevel logistic regression modelling to investigate the effect of adjustment for individual and ecological risk factors on the between-centre variation in the prevalence of recent wheeze. Adjustment for single individual-level risk factors changed the centre-level variation from a reduction of up to 8.4% (and 8.5% for atopy) to an increase of up to 6.8%. Modeling the 11 most influential environmental factors among all children simultaneously, the centre-level variation changed little overall (2.4% increase). Modelling only factors that decreased the variance, the 6 most influential factors (synthetic and feather quilt, mother's smoking, heating stoves, dampness and foam pillows) in combination resulted in a 21% reduction in variance. Ecological (centre-level) risk factors generally explained higher proportions of the variation than did individual risk factors. Single environmental factors and aeroallergen sensitisation measured at the individual (child) level did not explain much of the between-center variation in wheeze prevalence
Effect of diet on asthma and allergic sensitisation in the International Study on Allergies and Asthma in Childhood (ISAAC) Phase Two
Full text linkBackground: The increasing prevalence of asthma and allergy might be related to diet, particularly in Western countries. A study was undertaken to assess the association between dietary factors, asthma and allergy in a large international study including objective measurements of atopy.
Methods: Between 1995 and 2005, cross-sectional studies were performed in 29 centres in 20 countries. Parental questionnaires were used to collect information on allergic diseases and exposure factors and data from 50 004 randomly selected schoolchildren (8-12 years, 29 579 with skin prick testing) were analysed. Random effect models for meta-analysis were applied to calculate combined ORs.
Results: Fruit intake was associated with a low prevalence of current wheeze in affluent (OR(adj) 0.86, 95% CI 0.73 to 1.02) and non-affluent countries (OR(adj) 0.71, 95% CI 0.57 to 0.88). Consumption of fish in affluent countries (OR(adj) 0.85, 95% CI 0.74 to 0.97) and of cooked green vegetables in non-affluent countries (OR(adj) 0.78, 95% CI 0.65 to 0.95) was associated with a lower prevalence of current wheeze. Overall, more frequent consumption of fruit, vegetables and fish was associated with a lower lifetime prevalence of asthma, whereas high burger consumption was associated with higher lifetime asthma prevalence. None of the food items was associated with allergic sensitisation. Except for fruit juice and fruit consumption, no associations were found with atopic wheeze. Food selection according to the 'Mediterranean diet' was associated with a lower prevalence of current wheeze and asthma ever (p(trend)=0.03).
Conclusion: Diet is associated with wheeze and asthma but not with allergic sensitisation in children. These results provide further evidence that adherence to the 'Mediterranean diet' may provide some protection against wheeze and asthma in childhood
Association of pertussis and measles infections and immunizations with asthma and allergic sensitization in ISAAC Phase Two
Full text linkBackground: Many studies report that damp housing conditions are associated with respiratory symptoms. Less is known about mechanisms and possible effect modifiers. Studies of dampness in relation to allergic sensitization and eczema are scarce.
Objective: We study the influence of damp housing conditions world-wide on symptoms and objective outcomes.
Methods: Cross-sectional studies of 8-12-year-old children in 20 countries used standardized methodology from Phase Two of the International Study of Asthma and Allergies in Childhood (ISAAC). Symptoms of asthma, rhinitis and eczema, plus residential exposure to dampness and moulds, were ascertained by parental questionnaires (n = 46 051). Skin examination, skin prick tests (n = 26 967) and hypertonic saline bronchial challenge (n = 5713) were performed. In subsamples stratified by wheeze (n = 1175), dust was sampled and analysed for house dust mite (HDM) allergens and endotoxin.
Results: Current exposure to dampness was more common for wheezy children (pooled odds ratio 1.58, 95% CI 1.40-1.79) and was associated with greater symptom severity among wheezers, irrespective of atopy. A significant (P < 0.01) adverse effect of dampness was also seen for cough and phlegm, rhinitis and reported eczema, but not for examined eczema, nor bronchial hyperresponsiveness. HDM sensitization was more common in damp homes (OR 1.16, 1.03-1.32). HDM-allergen levels were higher in damp homes and were positively associated with HDM-sensitization, but not wheeze.
Conclusion: A consistent association of dampness with respiratory and other symptoms was found in both affluent and non-affluent countries, among both atopic and non-atopic children. HDM exposure and sensitization may contribute, but the link seems to be related principally to non-atopic mechanisms
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Lack of evidence for a protective effect of prolonged breastfeeding on childhood eczema: lessons from the International Study of Asthma and Allergies in Childhood (ISAAC) Phase Two
Full text linkBackground: Exclusive breastfeeding for at least 4 months is recommended by many governments and allergy organizations to prevent allergic disease.
Objectives: To investigate whether exclusive breastfeeding protects against childhood eczema.
Methods: Study subjects comprised 51,119 randomly selected 8- to 12-year-old schoolchildren in 21 countries. Information on eczema and breastfeeding was gathered by parental questionnaire. Children were also examined for flexural eczema and underwent skin prick testing. Odds ratios (ORs) were calculated for each study centre and then pooled across populations.
Results: There was a small increase in the risk of reported 'eczema ever' in association with 'breastfeeding ever' and breastfeeding 6 months (pooled adjusted OR 1·09, 95% CI 0·94-1·26). Risk estimates were very similar for exclusive breastfeeding 4 months and for eczema symptoms in the past 12 months and eczema on skin examination. As for more severe eczema, breastfeeding per se conveyed a risk reduction on sleep disturbed eczema (pooled adjusted OR 0·71, 95% CI 0·53-0·96), but this effect was lost where children had been exclusively breastfed for > 4 months (pooled adjusted OR 1·02, 95% CI 0·67-1·54). Allergic sensitization and a history of maternal allergic disease did not modify any of these findings.
Conclusions: Although there was a protective effect of ever having been breastfed on more severe disease, we found no evidence that exclusive breastfeeding for 4 months or longer protects against eczema. Our results are consistent with findings from a recent systematic review of prospective studies. The U.K. breastfeeding guidelines with regard to eczema should be reviewed. Intervention studies are now required to explore how and when solids should be introduced alongside breastfeeding to aid protection against eczema and other allergic diseases
Tuberculosis, bacillus Calmette–Guérin vaccination, and allergic disease: Findings from the International Study of Asthma and Allergies in Childhood Phase Two
Full text linkSome have suggested a protective effect of tuberculosis (TB) infection on allergic disease risk, but few studies have examined the association between the two. We therefore investigated whether TB disease and bacillus Calmette-Guérin (BCG) vaccination in early life protect against allergic disease. Information on allergic disease symptoms, past TB disease, and BCG vaccination as well as potential confounding factors was gathered by parental questionnaire from a randomly selected subset of 23,901 8- to 12-yr-old schoolchildren in 20 centers in both developed and developing countries. Children were also physically examined for flexural eczema and underwent skin prick testing. Pooled odds ratio (OR) estimates and corresponding 95% confidence intervals (CIs) across study centers were calculated, using random effects meta-analysis models. There were 245 (1.0%) reported cases of TB disease, and 66.3% (15,857) of all children received the BCG vaccine. Asthma, hay fever, and flexural eczema symptoms in the past year as well as flexural eczema on skin examination were all positively linked to a history of TB (adjusted pooled OR 'wheeze in the past year' = 2.27, 95% CI 1.52-3.41; adjusted pooled OR 'hay fever symptoms in the past year' = 2.23, 1.22-4.09; adjusted pooled OR 'flexural eczema symptoms in the past year' = 3.21, 2.01-5.12; adjusted pooled OR 'flexural eczema on skin examination' = 4.04, 1.71-9.56). Even higher risk estimates were seen for severe asthma and eczema symptoms [adjusted OR = 4.02 (2.17-7.47) and adjusted OR = 6.31 (2.19-18.17), respectively]. There was no significant association between past TB and skin prick test positivity (adjusted pooled OR = 1.32, 0.87-2.02). BCG vaccination during the first year of life was also not associated with any of the allergy outcomes. We found a uniform positive association between TB and all allergic disease outcomes, including eczema on skin examination. As this was a cross-sectional study, it is unclear whether this positive association is attributable to a causal relationship, and further longitudinal studies are required
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