Association of asthma symptoms and severity with indoor bioaerosols (original) (raw)
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Relationships between molds and asthma suggesting non-allergic mechanisms. A rural-urban comparison
Pediatric Allergy and Immunology, 2013
Background: A fungal index, based on specific microbial volatile organic compounds (MVOCs) emission, was employed and related to asthma in children from rural and urban dwellings after stratification on the children atopic status. Methods: A nested case-control design was used to draw, from 2 cross-sectional surveys, 20 asthmatics and 26 controls living in urban areas, and 24 asthmatics and 25 controls in rural areas. MVOCs levels were assessed in the living-room during one week; during that week, children performed clinical tests and their parents were invited to fill in a questionnaire on respiratory health. Results: According to the objective fungal index, 70.5% of cases and 49.0% of controls were exposed to molds. More children with current asthma had experienced mold exposure in their homes (OR=3.38, 95% CI (1.16; 9.90)), especially amongst children living in rural areas. Atopic status modified this association: exposure to molds was found to be related to current asthma only in non-atopic children (OR=10.42, 95% CI (2.42; 44.81)). Among urban -dwelling children that could be screened at hospital, asthmatic children living in contaminated dwellings had a higher proportion of blood neutrophils and a lower FEV 1 (forced expiratory volume in 1 second) than nonexposed ones. Conclusion: Our findings based on an objective assessment of MVOCs suggest adverse respiratory effects of molds. Our results suggest that when looking at the aetiology of non-atopic asthma, mold exposure should be systematically assessed.
The role of molds in the relation between indoor environment and atopy in asthma patients
Journal of research in medical sciences : the official journal of Isfahan University of Medical Sciences, 2013
The effect of mold fungi to allergic sensitization is not well-known. We aimed to evaluate the role of molds in the relation between indoor environment and atopy in asthmatics. The air samples obtained from 66 stable asthmatics and 35 control subject's houses were sprayed into Sabouraud dextrose agar. Allergy skin testing were performed in both groups. The temperature and humidity of each house were measured. The incidence of atopy was similar in cases (59.1%) and controls (51.4%). The average amount of mold was 35.9 CFU/m(3) and 34.3 CFU/m(3), respectively. The number of household residents was positively correlated with the amount of molds. There was no difference in the amount of mold with respect to dosage of inhaler corticosteroids as well as symptom levels in asthmatics. The most frequently encountered allergens were Dermatophagoides farinae/Dermatophagoides pteronyssinus, grass/weeds and molds. Spending childhood in a village was more common among atopics. Living environm...
Mouldy houses influence symptoms of asthma among atopic individuals
Clinical <html_ent glyph="@amp;" ascii="&"/> Experimental Allergy, 2002
Background The in¯uence of current levels of indoor fungi on asthma is a controversial issue that needs to be resolved in order to advise patients appropriately. Objective To assess the seasonal variation in indoor fungal levels and the impact of these levels on asthma among mould-sensitized individuals. Methods Thirty-®ve young adults with current asthma and sensitization to fungi were visited four times over 1 year. At each home visit a questionnaire was administered and samples of dust and air were collected. Participants also recorded information on symptoms, peak expiratory¯ows (PEF) and medication use. Dust samples were analysed for house dust mite allergen (Der p 1) and total fungal biomass (ergosterol). Total and genus-speci®c fungal propagules were identi®ed in air samples. Seasonal variation in allergen levels and signi®cant independent effects of fungal levels on peak¯ow variability (PFV) were identi®ed by repeated measures analysis of variance. Results Signi®cant seasonal variations were observed in viable airborne fungi, ergosterol levels in the¯oor dust and PFV. PFV correlated signi®cantly with symptom scores and the dose of reliever medication. PFV was also signi®cantly associated with smoking and visible mould. The association between visible mould and PFV was independent of season, smoking and the dose of reliever medication. However, there was no association between total fungi, speci®c fungi or ergosterol and PFV. Der p 1 levels had no signi®cant in¯uence on asthma, even in HDM-sensitized individuals. Conclusions Mouldy homes adversely in¯uence asthma in asthmatics sensitized to fungi.
Environmental Research, 2013
Higher values of the Environmental Relative Moldiness Index (ERMI), a DNA-based method for quantifying indoor molds, have been associated with asthma in children. In this study, settled dust samples were collected from the homes of adults with asthma, rhinitis, or both conditions (n=139 homes) in Northern California. The ERMI values for these samples were compared to those from dust collected in homes from the same geographic region randomly selected as part of the 2006 American Healthy Home Survey (n=44). The median ERMI value in homes of adult with airway disease (6) was significantly greater than median ERMI value (2) in the randomly selected homes (p<0.0001). In this study in northern California, the homes of adults with asthma had ERMI values consistent with a heavier burden of indoor mold than that measured in other homes from the same region.
Household mold and dust allergens: Exposure, sensitization and childhood asthma morbidity
Environmental Research, 2012
Background: Few studies address concurrent exposures to common household allergens, specific allergen sensitization and childhood asthma morbidity. Objective: To identify levels of allergen exposures that trigger asthma exacerbations in sensitized individuals. Methods: We sampled homes for common indoor allergens (fungi, dust mites (Der p 1, Der f 1), cat (Fel d 1), dog (Can f 1) and cockroach (Bla g 1)) for levels associated with respiratory responses among schoolaged children with asthma (N ¼ 1233) in a month-long study. Blood samples for allergy testing and samples of airborne fungi and settled dust were collected at enrollment. Symptoms and medication use were recorded on calendars. Combined effects of specific allergen sensitization and level of exposure on wheeze, persistent cough, rescue medication use and a 5-level asthma severity score were examined using ordered logistic regression. Results: Children sensitized and exposed to any Penicillium experienced increased risk of wheeze (odds ratio [OR] 2.12 95% confidence interval [CI] 1.12, 4.04), persistent cough (OR 2.01 95% CI 1.05, 3.85) and higher asthma severity score (OR 1.99 95% CI 1.06, 3.72) compared to those not sensitized or sensitized but unexposed. Children sensitized and exposed to pet allergen were at significantly increased risk of wheeze (by 39% and 53% for Fel d 1 40.12 mg/g and Can f 1 41.2 mg/g, respectively). Increased rescue medication use was significantly associated with sensitization and exposure to Der p 1 40.10 mg/g (by 47%) and Fel d 14 0.12 mg/g (by 32%). Conclusion: Asthmatic children sensitized and exposed to low levels of common household allergens Penicillium, Der p 1, Fel d 1 and Can f 1 are at significant risk for increased morbidity.
Quantitative PCR analysis of molds in the dust from homes of asthmatic children in North Carolina
Journal of Environmental Monitoring, 2007
The vacuum bag (VB) dust from the homes of 19 asthmatic children in North Carolina (NC) was analyzed by mold specific quantitative PCR. These results were compared to the analysis of the VB dust from 176 homes in the HUD, American Healthy Home Survey of homes in the US. The Environmental Relative Moldiness Index (ERMI) was calculated for each of the homes. The mean and standard deviation (SD) of the ERMI values in the homes of the NC asthmatic children was 16.4 (6.77), compared to the HUD survey VB ERMI value mean and SD of 11.2 (6.72), and was significantly greater (t-test, p = 0.003) in the NC asthmatic children's homes. The molds Chaetomium globosum, Aspergillus fumigatus, and the Eurotium Group were the primary species in the NC homes of asthmatics, making the ERMI values significantly higher (p o 0.02 for each). Vacuum bag dust analysis may be a useful method for estimating the mold burden in a home.
Journal of Allergy and Clinical Immunology, 2002
Background: The effects of home dampness and mold exposure on adult asthma are not clear. Objective: We aimed to investigate the associations between housing characteristics related to dampness, mold exposure, and house dust mite levels and adult asthma in 38 study centers from the European Community Respiratory Health Survey. Methods: Data about the present home, heating and ventilation systems, double glazing, floor covers, recent water damage, and mold exposure were obtained by means of an interviewer-led questionnaire. The associations between these factors and asthma, as defined on the basis of symptoms in the last year, and of bronchial responsiveness, as determined with methacholine challenge, were evaluated. Odds ratios (ORs) were obtained by using random-effects meta-analyses adjusted within study centers for sex, age group, and smoking status. Results: Fitted carpets and rugs in the bedroom were related to fewer asthma symptoms and bronchial responsiveness (OR range, 0.69-0.91). This effect was consistent across centers and more pronounced among house dust mite-sensitized individuals. Reported mold exposure in the last year was associated with asthma symptoms and bronchial responsiveness (OR range, 1.14-1.44). This effect was homogeneous among centers and stronger in subjects sensitized to Cladosporium species. In centers with a higher prevalence of asthma, the prevalence of reported indoor mold exposure was also high. This association was observed for reported mold exposure by asthmatic subjects (Spearman r s = 0.46), as well as reported mold exposure by nonasthmatic subjects (r s = 0.54). Reported mold exposure was highest in older houses with recent water damage. Conclusion: We conclude that indoor mold growth has an adverse effect on adult asthma. (J Allergy Clin Immunol 2002;110:285-92.)
Asian Pacific journal of allergy and immunology / launched by the Allergy and Immunology Society of Thailand, 2008
Although the relationship between asthma severity and exposure to airborne fungi has been well studied, little is known about the contribution of outdoor molds to the symptoms of children monosensitized to molds. In this study, we aimed to investigate the effect of outdoor mold spore concentrations on daily asthma and/or rhinitis scores in children monosensitized to molds. Nineteen children with asthma and/or rhinitis sensitized only to molds recorded their daily symptoms and PEF values to the diaries, from February 2005 to January 2006. Additionally, mold spores were measured daily using a Burkard 7-day recording volumetric spore trap in city atmosphere and compared with meteorological data. Total number of mold spores in atmosphere was found to be 352,867 spore/m3 during the study period. Cladosporium (53%) was the most common encountered outdoor fungi, followed by Altemaria (29%) and 1-septate Ascospore (3%). Outdoor fungi concentrations were significantly correlated with mean mo...
American Journal of Respiratory and Critical Care Medicine, 2001
We assessed the influence of current indoor levels of fungi, house dust mite allergen ( Der p 1), and cat allergen ( Fel d 1) on sensitization and asthma in adults. A total of 485 adults answered a questionnaire and had skin prick tests and lung function tests. Dust and air samples were collected from their bedrooms. The dust was analyzed for Der p 1, Fel d 1, and fungal biomass (ergosterol). Fungal propagules were measured in air samples. Current asthma was defined as having wheezed during the past 12 mo plus bronchial hyperreactivity (BHR) to methacholine. High exposure to total airborne fungi was associated with increased BHR, but perhaps paradoxically with a lower risk of being sensitized to fungi. Ergosterol levels in floor dust were a risk factor both for being sensitized to fungi and having wheezed within the last year. High Fel d 1 levels in floor dust were found to increase the risk of being sensitized to cats and in beds to increase the risk of current asthma. Although Der p 1 levels in homes were high, people exposed to high Der p 1 levels in floor dust were less likely to be sensitized to house dust mites or to have wheezed within the past year. Current indoor levels of fungi and Fel d 1, but not Der p 1, influenced sensitization and asthma in adults with high dust mite exposure.
Visually observed mold and moldy odor versus quantitatively measured microbial exposure in homes
Science of The Total Environment, 2010
The main study objective was to compare different methods for assessing mold exposure in conjunction with an epidemiologic study on the development of children's asthma. Homes of 184 children were assessed for mold by visual observations and dust sampling at child's age 1 (Year 1). Similar assessment supplemented with air sampling was conducted in Year 7. Samples were analyzed for endotoxin, (1-3)-β-D-glucan, and fungal spores. The Mold Specific Quantitative Polymerase Chain Reaction assay was used to analyze 36 mold species in dust samples, and the Environmental Relative Moldiness Index (ERMI) was calculated. Homes were categorized based on three criteria: 1) visible mold damage, 2) moldy odor, and 3) ERMI. Even for homes where families had not moved, Year 7 endotoxin and (1-3)-β-D-glucan exposures were significantly higher than those in Year 1 (p<0.001), whereas no difference was seen for ERMI (p=0.78). Microbial concentrations were not consistently associated with visible mold damage categories, but were consistently higher in homes with moldy odor and in homes that had high ERMI. Low correlations between results in air and dust samples indicate different types or durations of potential microbial exposures from dust vs. air. Future analysis will indicate which, if any, of the assessment methods is associated with the development of asthma.