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Mould spores constitute the largest portion of biologic particulate matter suspended in the outdoor atmosphere. There is no universal method for collecting airborne mould spores. The most used sampler, Hirst's apparatus, operates continuously and gives results in individual spores per cubic metre of air. Spore concentrations depend on available substrates, human activities such as agriculture, season, diurnal meteorological variations and climate changes. Under natural conditions, concentrations of over 100,000 spores per cubic metre are not exceptional. Cladosporium is the most commonly identified outdoor mould. The association between respiratory health and outdoor mould spore exposure has been assessed in clinical studies, and also by cross-sectional, and less often longitudinal, epidemiological studies. The relationship between asthma exacerbations and specific mould spores has been demonstrated in longitudinal studies. Cross sectional studies have related measurements of mould spore concentrations to severity of bronchial symptoms, drug consumption and peak-flow measurements in groups of asthmatic subjects. Ecological time-series studies use daily indicators of asthma exacerbations (emergency room visits, hospitalizations) within the general population. The moulds mainly incriminated are Cladosporium and Alternaria. They are associated with seasonal, but also perennial, asthma and rhinitis. Further studies are needed to better assess the impact of outdoor moulds on health, particularly basidiomycetes. Studies with molecular biology tools are probably a way forward., (Copyright © 2018 SPLF. Published by Elsevier Masson SAS. All rights reserved.)

Background: The results of international epidemiological surveys show large geographical variations in skin test reactivity but do not provide a rationale for such variations., Objective: To assess the relationship between climate and allergic sensitization in schoolchildren., Methods: In the present study, we analyzed data from a multicenter, epidemiological survey that included 6,461 schoolchildren, aged 9-11 years, living in 6 French cities scattered around France. The protocol also included a battery of skin prick tests to common airborne allergens. The crude prevalence of sensitization to each allergen was estimated for each city and then adjusted for potential confounding factors. This analysis was repeated for monosensitization and for allergens grouped into 2 categories: indoor allergens, i.e., house dust mite (HDM), cat, and cockroach allergens, and outdoor allergens, i.e., birch pollen, grass pollen, and Alternaria. We also grouped cities according to their location on the coast, i.e., Marseille and Bordeaux, or inland, i.e., Créteil, Clermont-Ferrand, Reims, and Strasbourg., Results: A difference in prevalence of sensitization to each airborne allergen or allergens grouped into indoor and outdoor categories was found between cities, even after adjusting for potential confounding factors. Also, a higher prevalence of sensitization to HDM, cat dander, and, broadly speaking, indoor allergens, was found in children living on the coast than in those living inland, whereas they showed a lower prevalence of sensitization to birch pollen. Between-city differences in the prevalence of monosensitization were also statistically significant. Children living in coastal cities had a higher rate of monosensitization to indoor allergens and a lower prevalence of sensitization to birch pollen. The higher prevalence of allergic sensitization in children from coastal cities is most likely due to climatic conditions, such as proximity from sea and humidity. Differences in sensitization to birch allergens could be due to differential exposure to these pollen., Conclusion: These results indicate a role of environmental exposure in sensitization to perennial as well as seasonal allergens., (© 2017 S. Karger AG, Basel.)

Background: Most panel studies focusing on rhinitis and conjunctivitis symptoms and birch pollen have been performed on a linear basis and have not included air pollution and meteorological variables as potential confounders. The objective of this panel study was to assess the relationship between symptoms of seasonal allergic rhinoconjunctivitis and daily airborne birch pollen concentrations, checking with adequate statistical tools the shapes of concentration-response curves and controlling for confounders., Methods: The severity of rhinitis, conjunctivitis, and bronchial symptoms was recorded daily in March and April 2010 (3,311 person-days) in 61 seasonal allergic rhinoconjunctivitis patients sensitized to birch. Data were analyzed with generalized additive and generalized estimating equation models to quantify the effects of birch pollens., Results: The relationship between birch pollen and the percentage of patients with nasal, ocular and bronchial symptoms was linear until birch daily average concentrations of, respectively, 110, 70, and 70 grains/m(3); it reached a plateau thereafter. For an increase of 10 grains/m(3), the OR (95% CI) for nasal, ocular, and bronchial symptoms were, respectively, 1.07 (1.03-1.12), 1.17 (1.08-1.27), and 1.12 (1.03-1.21). At the beginning of the season, no nasal or ocular symptoms were observed below a threshold of 30 grains/m(3)., Conclusions: Adequate modeling regression shows that the clinical response to natural exposure to birch pollen in sensitized patients varies during Betula pollen season, with a threshold at the beginning of the season, while over the whole season the relationship is linear for nasal, ocular, and bronchial symptoms up to a saturation point, followed by a plateau., (© 2013 S. Karger AG, Basel.)

Objectives: Ragweed, Ambrosia artemisiifolia, is a highly allergenic annual herbaceous plant that is spreading quickly across the globe. Few studies have investigated the relationship between ragweed pollen counts and hay fever symptoms. We investigate the dose-response relationship between ragweed exposure in patients sensitized to ragweed and daily hay fever symptoms., Method: A panel study was conducted among 31 adult patients sensitized to A artemisiifolia in France and Switzerland. Rhinitis, conjunctivitis, and bronchial symptoms were recorded daily, as well as daily pollen counts of ragweed, air pollutants, and meteorological data over 2 successive years. Data were analyzed with generalized estimating equation models to quantify effects of ragweed pollen whilst controlling for confounders., Results: The relationship between ragweed pollen and the percentage of patients with nasal, ocular, and bronchial symptoms was linear. For every increase of 10 grains/m3, the odds ratio (OR) (95% confidence interval) for nasal symptoms was, in 2009, 1.18 [1.04-1.35] on weekdays and 1.43 [1.16-1.75] at weekends, and in 2010, 1.04 [1.00-1.07] on weekdays and 1.25 [1.06-1.46] at weekends.The OR for ocular symptoms was 1.32 [1.16-1.56] in 2009 and 1.05 [1.02-1.07] in 2010. Finally, the OR for bronchial symptoms was 1.14 [1.03-1.25] in 2009 and 1.03 [0.97-1.08] in 2010., Conclusion: There is a statistically significant linear relationship between ragweed pollen counts and hay fever symptoms. Our study shows that nasal symptoms differ on weekdays and at weekends.

Purpose: This study examined the hypothesis that emotion and conduct problems (ECPs) may modify the relationships between ambient air pollutants and childhood asthma and eczema., Methods: In the cross-sectional study, 4209 French schoolchildren (aged 10e12 years) were investigated between March 1999 and October 2000. Ambient air pollutants exposures were estimated with dispersion modeling. Health outcomes and ECPs were evaluated by validated questionnaires, completed by the parents. Marginal models were used to analyze the relationships of exposures to ambient air pollutants and/or ECPs to asthma phenotypes and current eczema, adjusting for potential confounders., Results: In our population, interactions were found between ECPs and exposures to ambient air pollutants (benzene, carbon monoxide, nitrogen dioxide, nitrogen oxides, particulate matter with an aerodynamic diameter below 10 mm, volatile organic compounds) (P < .20). In addition, ECPs were related to current wheezing (adjusted prevalence odds ratio [aOR], 2.35; 95% confidence interval [CI], 1.59e3.47), current doctor-diagnosed asthma (aOR, 1.82; 95% CI, 1.25e2.66), and current eczema (aOR, 2.21; 95% CI, 1.61e3.02). Children with ECPs had 1.17e1.51 times higher aORs for the associations between ambient air pollutants and asthma phenotypes and current eczema than those without ECPs., Conclusions: ECPs may modify the relationships between ambient air pollutants and childhood asthma and eczema., (2013 Elsevier Inc. All rights reserved.)

Introduction: Benzene is a ubiquitous pollutant of both indoor and outdoor environments which impacts on respiratory health. Our aim was to relate urinary S-phenylmercapturic acid (S-PMA), a biomarker of benzene exposure, to benzene concentrations and related sources at home and asthma in a population-based sample of children., Methods: Exposure to benzene was assessed in the dwellings of 63 children (32 asthmatics and 31 controls) through the identification of sources of benzene and in situ assessments with passive samplers. The determination of urinary S-PMA was obtained by liquid chromatography-mass spectrometry., Results: At home, asthmatics were significantly more polluted by benzene levels from ambient sampling than controls (p ≤ 0.05). Benzene exposure significantly aggravated asthma symptoms overall in non-atopic children (OR = 10.10; 95% confidence interval: 10.10). Urinary S-PMA was significantly associated with benzene concentrations in the entire population (regression coefficient = 0.28, 95% CI: 0.07-0.49; p < 0.05) and asthma (OR = 7.69; 95% CI: 1.37-42.52 for an increase of 1 µg/g creatinine of urinary S-PMA). However, after adjustment for environmental tobacco smoking exposure, familial allergy, age and sex, the latter relationship was no more significant (OR = 4.95; 95% CI: 0.91-27.4, p < 0.10). Both benzene concentrations and urinary S-PMA concentrations were higher in dwelling built after 1948 and in flats., Conclusions: Our study suggests a relationship between childhood asthma and benzene concentrations at home, even at low levels of this pollutant. This was confirmed when considering urinary S-PMA, which was related to both benzene concentrations and asthma. Further epidemiological and toxicological studies are needed to confirm our results.

The impact of chronic urban air pollution on asthma and allergy remains controversial, probably because exposure is difficult to evaluate. In this cross-sectional epidemiological survey of 9- to 11-year-old children living in six French towns, levels of air pollution were estimated by using dispersion models that take into account background air pollution levels along with traffic density, topography and meteorological conditions. We estimated three-year exposure, in the school environment, to benzene, volatile organic compounds, SO2, particles less than 10 microns in diameter (PM10), nitrous oxides (NO2 and NOx) and CO, which are the main urban air pollutants. Several health indicators were gathered by means of a questionnaire, a physical examination, skin prick testing, and measurement of peak-flow variations following an exercise test. Among the nearly 5000 children who had been living in the survey area for at least three years, the 12-month and cumulative prevalence rates of asthma and exercise-induced hyper-reactivity correlated with estimated levels of benzene, SO2, PM10, NOx and CO. The 12-month and cumulative prevalence rates of atopic dermatitis correlated with estimated benzene, PM10, NO2, NOx and CO levels. Pollen sensitization correlated with benzene and PM10 levels, and the cumulative prevalence of allergic rhinitis correlated with the PM10 level. These associations remained statistically significant among children who had spent their entire lives in the same community.

Background: Fine particulate matter has been linked to allergies by experimental and epidemiological data having used aggregated data or concentrations provided by fixed-site monitoring stations, which may have led to misclassification of individual exposure to air pollution., Methods: A semi-individual design was employed to relate individual data on asthma and allergy of 5338 school children (10.4 +/- 0.7 years) attending 108 randomly chosen schools in 6 French cities to the concentrations of PM2.5 (fine particles with aerodynamic diameter 2.5 microm) assessed in proximity of their homes. Children underwent a medical visit including skin prick test (SPT) to common allergens, exercise-induced bronchial (EIB) reactivity and skin examination for flexural dermatitis. Their parents filled in a standardised health questionnaire., Results: After adjustment for confounders and NO2 as a potential modifier, the odds of suffering from EIB and flexural dermatitis at the period of the survey, past year atopic asthma and SPT positivity to indoor allergens were significantly increased in residential settings with PM2.5 concentrations exceeding 10 microg/m3 (WHO air quality limit values). The relationships were strengthened in long-term residents (current address for at least 8 years)., Conclusions: Findings support the hypothesis that changes in allergy prevalence observed in recent decades might be partly related to interactions between traffic-related air pollution and allergens. Further longitudinal investigations are needed to corroborate such results.

Background: The impact of air pollution on asthma and allergies still remains a debate., Objective: Our cross-sectional study was intended to analyse the associations between long-term exposure to background air pollution and atopic and respiratory outcomes in a large population-based sample of schoolchildren., Methods: Six thousand six hundred and seventy-two children aged 9-11 years recruited from 108 randomly schools in six French cities underwent a clinical examination including a skin prick test (SPT) to common allergens, exercise-induced bronchial reactivity (EIB) and skin examination for flexural dermatitis. The prevalence of asthma, allergic rhinitis (AR) and atopic dermatitis was assessed by a standardized health questionnaire completed by the parents. Three-year-averaged concentrations of air pollutants (NO2, SO2, PM10 and O3) were calculated at children' schools using measurements of background monitoring stations., Results: After adjusting for confounders, EIB, lifetime asthma and lifetime AR were found to be positively related to an increase in the exposure to SO2, PM10 and O3. The adjusted odds ratios (aOR) per increase of 5 microg/m3 of SO2 was 1.39 (95% confidence interval (CI)=1.15-1.66) for EIB and 1.19 (1.00-1.41) for lifetime asthma. The aOR for lifetime AR per increase of 10 microg/m3 of PM10 was 1.32 (CI=1.04-1.68). Moreover, SPT positivity was associated with O3 (aOR=1.34; CI=1.24-1.46). Associations with past year symptoms were consistent, even if not always statistically significant. Results persisted in long-term resident (current address for at least 8 years) children. However, no consistent positive association was found with NO2., Conclusions: A moderate increase in long-term exposure to background ambient air pollution was associated with an increased prevalence of respiratory and atopic indicators in children.

The authors carried out a pilot study in Clermont-Ferrand (France) over the period from 2000 to 2001 to analyze the short-term relationship between daily variations in rhinitis and allergic conjunctivitis and daily variations in pollen counts. Data from the ERASME database made it possible to identify all the individuals for whom at least one drug was prescribed to treat rhinitis or allergic conjunctivitis. Ten allergenic pollens were studied, and a Poisson regression model with penalized spline functions was used. A positive and significant association was found for pollens of Betula, Cupressaceae, Quercus, Fraxinus, and Poaceae. The relative risks varied between 1.3 (95% confidence interval [CI] = 1.0-1.5) and 1.2 (95% CI = 1.1-1.5) for an interquartile range increase of daily pollen counts of Cupressaceae (13 grains/m3) and of Betula (45 grains/m3), respectively. Further analyses, in particular, those using longer time series, are necessary to confirm these results.