Changes in indoor allergen and fungal levels predict changes in asthma activity among young adults

Indoor microbiome and allergic diseases: From theoretical advances to prevention strategies

The prevalence of allergic diseases, such as asthma, rhinitis, eczema, and sick building syndrome (SBS), has increased drastically in the past few decades. Current medications can only relieve the symptoms but not cure these diseases whose development is suggested to be greatly impacted by the indoor microbiome. However, no study comprehensively summarizes the progress and general rules in the field, impeding subsequent translational application. To close knowledge gaps between theoretical research and practical application, we conducted a comprehensive literature review to summarize the epidemiological, environmental, and molecular evidence of indoor microbiome studies. Epidemiological evidence shows that the potential protective indoor microorganisms for asthma are mainly from the phyla Actinobacteria and Proteobacteria, and the risk microorganisms are mainly from Bacilli, Clostridia, and Bacteroidia. Due to extremely high microbial diversity and geographic variation, different health-associated species/genera are detected in different regions. Compared with indoor microbial composition, indoor metabolites show more consistent associations with health, including microbial volatile organic compounds (MVOCs), lipopolysaccharides (LPS), indole derivatives, and flavonoids. Therefore, indoor metabolites could be a better indicator than indoor microbial taxa for environmental assessments and health outcome prediction. The interaction between the indoor microbiome and environmental characteristics (surrounding greenness, relative humidity, building confinement, and CO2 concentration) and immunology effects of indoor microorganisms (inflammatory cytokines and pattern recognition receptors) are briefly reviewed to provide new insights for disease prevention and treatment. Widely used tools in indoor microbiome studies are introduced to facilitate standard practice and the precise identification of health-related targets.

Effect of Dermatophagoides pteronyssinus extract on the expression of genes involved in inflammation and tissue remodeling by peripheral blood mononuclear cells of allergic asthma patients

PURPOSE

House dust mite allergy constitutes a risk factor for asthma development and is associated with a faster decline of lung function in allergic asthmatics (AAs). To evaluate the effect of Dermatophagoides pteronyssinus (Dp) allergens on the expression of genes involved in inflammation and tissue remodeling by peripheral blood mononuclear cells (PBMCs) isolated from the blood of AAs.

MATERIALS AND METHODS

The cells from AAs, allergic rhinitis without asthma patients (ARs), and healthy controls (HCs) were cultured in the presence of Dp, lipopolysaccharide (LPS), or without any stimulation. The expression of 84 genes was evaluated using a low-density microarray whereas, the quantitative expression analysis of selected genes was performed using a real-time polymerase chain reaction. The concentration of selected proteins in the cell culture supernatants was assessed using ELISA.

RESULTS

Stimulation of PBMCs with Dp and LPS resulted in a significant upregulation of 8 and 15 among 84 studied genes, respectively. The greatest upregulation was observed for CCL2 and CCL3 using Dp and LPS, respectively. In comparison with HCs, in AAs, significantly increased upregulation of CCL2 in response to Dp was found. The secretion of CCL2 and CCL3 by PBMCs reflected the pattern of gene expression at the mRNA level. The mean Dp-stimulated secretion of CCL2 by PBMCs of ARs was less than in AAs (p ​< ​0.01), both being notably greater than in the HCs (p ​< ​0.01).

CONCLUSION

Rapid and potent upregulation of CCL2 expression by PBMCs in response to Dp may constitute an important contribution to the development of allergic asthma.

Risk factors for asthma in patients with allergic rhinitis in eastern China

BACKGROUND

Asthma is one of the most common chronic diseases among children and adults and can lead to a high health and socioeconomic burden. Allergic rhinitis (AR) often precedes the development of asthma. This study aims to clarify the risk factors for cocurrent asthma in patients with AR in eastern China.

METHODS

A cross-sectional study of 3739 patients with AR was performed in eastern China. Patients meeting the criteria for AR were evaluated using a skin-prick test (SPT) of 16 common aeroallergens. A logistic regression analysis was used to assess the risk factors of asthma in patients with AR.

RESULTS

The prevalence of asthma in patients with AR was 14.23%. The patients sensitive to dust mites (D. farinae and D. pteronyssinus) had the highest prevalence (76.84% and 73.68%). A significant difference was found in sensitization to four types of allergens (D. farinae, D. pteronyssinus, dog dander, Alternaria alternata) in patients with AR with and without asthma. The strongest risk factor for asthma in patients with AR was an allergy to Aspergillus fumigatus (adjusted OR, 2.42; 95% CI, 1.50-3.90), followed by allergy to D. pteronyssinus (adjusted OR, 2.06; 1.30-3.27), and allergy to dog dander (adjusted OR, 1.92; 1.24-2.97). Various risk factors that are independently associated with asthma in patients with AR were found in different age groups.

CONCLUSIONS

We observed a difference in risk factors in patients with AR with and without asthma. Clarifying the risk factors for asthma in patients with AR is important and may be beneficial to the optimal interventions of asthma.

Prevalence, Risk Factors and Impacts Related to Mould-Affected Housing: An Australian Integrative Review

In response to an Australian governmental inquiry into biotoxin-related illness, the purpose of this integrative review is to bring together the current state of evidence on the prevalence, risk factors and impacts related to mould-affected housing in an Australian context, in order to inform building, housing and health research, practice and policy. The robust integrative review methodology simultaneously sought quantitative and qualitative studies and grey literature from multiple disciplines, identifying only 45 studies directly relating to Australian housing and indoor mould. Twenty-one studies highlight negative health impacts relating to indoor residential mould, with asthma, respiratory, allergy conditions and emerging health concerns for chronic multiple-symptom presentation. The majority of studies reported risk factors for indoor mould including poor housing conditions, poor-quality rental accommodation, socioeconomic circumstance, age-related housing issues and concerns for surface/interstitial condensation and building defects in newer housing. Risks for indoor mould in both older and newer housing raise concerns for the extent of the problem of indoor mould in Australia. Understanding the national prevalence of housing risks and "root cause" associated with indoor mould is not conclusive from the limited existing evidence. Synthesis of this evidence reveals a lack of coverage on: (1) national and geographical representation, (2) climatical coverage, (3) housing typologies, (4) housing defects, (5) maintenance, (6) impact from urbanisation, and (7) occupant's behaviour. This integrative review was key in identifying emerging housing and health concerns, highlighting gaps in data and implications to be addressed by researchers, practice and policy and acts as a comprehensive holistic review process that can be applied to other countries.

Family, neighborhood and psychosocial environmental factors and their associations with asthma in Australia: a systematic review and Meta-analysis

OBJECTIVE

Various associations between different environmental exposures and asthma have been reported in different countries and populations. We aimed to investigate the associations between family, neighborhood and psychosocial environmental factors and asthma-symptoms in Australia by conducting a systematic review and meta-analysis.

DATA SOURCES

We analyzed the primary research studies conducted in Australia across multiple databases, including PubMed, EMBASE and Scopus, published between 2000 and 2020.

STUDY SELECTIONS

The reviews and analyses focused on the overall association of different environmental exposures with the exacerbation of asthma-symptoms or asthma-related hospital visits. Quality-effect meta-analysis was done to estimate the pooled odds ratio for different environmental exposures for asthma-symptoms.

RESULTS

Among the 4799 unique published articles found, 46 were included here for systematic review and 28 for meta-analysis. Our review found that psychosocial factors, including low socioeconomic condition, maternal depression, mental stress, ethnicity, and discrimination, are associated with asthma-symptoms. Pooled analysis was conducted on family and neighborhood environmental factors and revealed that environmental tobacco smoking (ETS) (OR 1·69, 95% CI 1·19-2·38), synthetic bedding (OR 1·91, 95% CI 1·48-2·47) and gas heaters (OR 1·40, 95% CI 1·12-1·76) had significant overall associations with asthma-symptoms in Australia.

CONCLUSION

Although the studies were heterogeneous, both systematic review and meta-analysis found several psychosocial and family environmental exposures significantly associated with asthma-symptoms. Further study to identify their causal relationship and modification may reduce asthma-symptoms in the Australian population.

Two new species of Cladosporium from leaf spots of Parispolyphylla in north-western Yunnan Province, China

BACKGROUND

During the survey of pathogenic fungi on medicinal plant leaves in Yunnan Province, China, two Cladosporium-like taxa were isolated from leaf spots of Parispolyphylla. Based on morphological characteristics and phylogenetic analysis of combined ITS, TEF1-α and ACT genes, two new species were discovered.

NEW INFORMATION

Two new species Cladosporiumyunnanensis and C.paris are introduced, the detailed descriptions and illustrations are provided. Morphology of the two new species is compared with other related Cladosporium species. This study widens the host diversity of the genus Cladosporium.

Association of indoor microbial aerosols with respiratory symptoms among under-five children: a systematic review and meta-analysis

BACKGROUND

Despite the recognition of the importance of indoor microbial exposures on children's health, the role of different microbial agents in development and aggravation of respiratory symptoms and diseases is only poorly understood. This study aimed to assess whether exposure to microbial aerosols within the indoor environment are associated with respiratory symptoms among children under-5 years of age.

METHODS

A systematic literature search was conducted on PubMed, Web of Science, GreenFILE, ScienceDirect, EMBASE and Cochrane library through February 2020. Studies that investigated the exposure-response relationship between components of the indoor microbial communities and respiratory symptoms among under-five children were eligible for inclusion. A random-effect meta-analysis was applied to estimate pooled relative risk (RR) and 95% confidence interval (CI) for study specific high versus low microbial exposures. The potential effect of individual studies on the overall estimate was evaluated using leave-one-out analysis, while heterogeneity was evaluated by I² statistics using RevMan 5.3.

RESULTS

Fifteen studies were eligible for inclusion in a meta-analysis. The pooled risk estimate suggested that increased microbial exposure was associated with an increased risk of respiratory symptoms [pooled relative risk (RR): 1.24 (1.09, 1.41), P = 0.001]. The association was strongest with exposure to a combination of Aspergillus, Penicillium, Cladosporium and Alternaria species [pooled RR: 1.73 (1.30, 2.31), P = 0.0002]. Stratified analysis revealed an increased risk of wheeze [pooled RR: 1.20 (1.05, 1.37), P = 0.007 and allergic rhinitis [RR: 1.18 (0.94, 1.98), P = 0.16] from any microbial exposure.

CONCLUSIONS

Microbial exposures are, in general, associated with risk of respiratory symptoms. Future studies are needed to study the indoor microbiome more comprehensively, and to investigate the mechanism of these associations.

Microbial Agents in the Indoor Environment: Associations with Health

There is international consensus that damp buildings and indoor mould can increase the risk of asthma, rhinitis, bronchitis and respiratory tract infections but we do not know which types of microbial agents that are causing the observed adverse health effects. Microbial indoor exposure is a broader concept than microbial growth in buildings. Other sources of indoor microbial exposure include the outdoor environment, humans (crowdedness) and furry pet keeping. Microbial exposure can have different health effects depending on the dose, different exposure route, genetic disposition and the timing of exposure. Microbial stimulation linked to large microbial diversity in early life can protect against disease development, especially for allergic asthma and atopy. Protective effects are more often reported for bacterial exposure and adverse health effects are more often linked to mould exposure. There are many studies on health associations for indoor exposure to endotoxin, mainly from homes. The risk of getting atopic asthma may be less if you are exposed to endotoxin in childhood but the risk of non-atopic asthma may increase if exposed to endotoxin especially in adulthood. Moreover, genetic disposition modifies health effects of endotoxin. Epidemiological studies on muramic acid (from gram-positive bacteria) or ergosterol (from mould) are few. Studies on health effects of indoor exposure to beta-1-3-glucan (from mould) have conflicting results (positive as well as negative associations). Epidemiological studies on health effects of indoor exposure to mycotoxins are very few. Some studies have reported health associations for MVOC, but it is unclear to what extent MVOC has microbial sources in indoor environments. Many studies have reported health associations for fungal DNA, especially as a risk factor for childhood asthma at home. Since most studies on health effects of indoor exposure to mould, bacteria and microbial agents are cross-sectional, it is difficult to draw conclusions on causality. More prospective studies on indoor microbial exposure are needed and studies should include other indoor environments than homes, such as day care centers, schools, hospitals and offices.

Morphology and Multi-Gene Phylogeny Reveal Pestalotiopsis pinicola sp. nov. and a New Host Record of Cladosporium anthropophilum from Edible Pine (Pinus armandii) Seeds in Yunnan Province, China

This study contributes new knowledge on the diversity of conidial fungi in edible pine (Pinus armandii) seeds found in Yunnan Province, China and emphasizes the importance of edible seed products to ensure food safety standards. We isolated two fungal species, one on the pine seed coat and the other on the endosperm of the pine seed. The two fungal species were identified as Pestalotiopsis pinicola sp. nov. and a new host record Cladosporium anthropophilum. Characteristic morphological features of Pestalotiopsis pinicola were used alongside results from multi-gene phylogenetic analysis to distinguish it from currently known species within the genus. Cladosporium anthropophilum was identified as a new host record based on morphological features and phylogenetic analysis. In addition, detailed descriptions, scanned electron microscopy morphology, illustrations, and phylogenetic trees are provided to show the placement of these species.

Jumping on the bed and associated increases of PM10, PM2.5, PM1, airborne endotoxin, bacteria, and fungi concentrations

Jumping on the bed is a favorite behavior of children; however, no study has investigated the increased air pollutants resulting from jumping on the bed. Therefore, we aimed to investigate the elevated concentrations of particulate matter (PM) and bioaerosols from jumping on the bed and making the bed. Simulation of jumping on the bed and making the bed was performed at sixty schoolchildren's houses in Taiwan. PM₁₀, PM_2.5, PM₁ (PM with aerodynamic diameter less than 10, 2.5, and 1 μm, respectively) and airborne bacteria, fungi and endotoxin concentrations were simultaneously measured over simulation and background periods. Our results show the increase of PM₁₀, PM_2.5, PM₁, airborne bacteria and fungi through the behavior of jumping on the bed (by 414 μg m-3, 353 μg m-3, 349 μg m-3, 6569 CFU m-3 and 978 CFU m-3, respectively). When making the bed, the PM₁₀, PM_2.5, PM₁, airborne bacteria and fungi also significantly increased by 4.69 μg m-3, 4.09 μg m-3, 4.15 μg m-3, 8569 CFU m-3, and 779 CFU m-3, respectively. Airborne endotoxin concentrations significantly increased by 21.76 EU m-3 following jumping on the bed and making the bed. Moreover, when jumping on the bed, higher PM_2.5 and PM₁ concentrations in houses with furry pets rather than no furry pets, and less airborne fungi in apartments than in townhouses were found. For making the bed, lower airborne fungi was found in houses using essential oils rather than no essential oils using. The airborne endotoxin concentrations were positively associated with furry pets and smokers in the homes and negatively correlated to the home with window opening with a statistical significance during the periods of jumping on the bed and making the bed. In conclusion, significant increases of PM and bioaerosols during jumping on the bed and making the bed may need to be concerned.

Fungal Sensitization Is Associated with Increased Risk of Life-Threatening Asthma

BACKGROUND

Fungal sensitization in patients with asthma has been associated with severe asthma and worse asthma outcomes.

OBJECTIVE

The purpose of this study was to determine the relationship between fungal and nonfungal sensitization, asthma severity, and clinical outcomes.

METHODS

A retrospective review of patients with asthma evaluated in an urban pulmonary subspecialty clinic in the United States was performed. Patients with fungal and nonfungal allergen sensitization were identified based on serum-specific immunoglobulin E (sIgE) testing. Demographic, clinical, laboratory, and spirometric data were obtained. The relationship between fungal sensitization and asthma outcomes was examined.

RESULTS

Of 390 patients with asthma identified, 307 had sIgE testing, of whom 53 (17.3%) had fungal sensitization, 117 (38.1%) had nonfungal sensitization, and 137 (44.6%) had no sensitization. Patients with fungal sensitization were more likely to be sensitized to ≥5 allergens than patients with nonfungal sensitization (66% for fungal vs 29% for nonfungal, P < .001). Serum IgE concentrations were highest in patients with fungal sensitization compared with patients with no sensitization or nonfungal sensitization (median, 825, 42, and 203 IU/mL, respectively, P < .001). Fungal sensitized patients were more likely to require intensive care unit (ICU) admission and mechanical ventilation than those with no sensitization or nonfungal sensitization (13.2%, 3.7%, and 3.4%, respectively, for ICU admission, P = .02; 11.3%, 1.5%, and 0.9%, respectively, for ventilation, P < .001).

CONCLUSIONS

Fungal sensitization is common in patients with asthma in an urban setting and is associated with greater sensitization to nonfungal allergens and increased risk of life-threatening asthma.

Clinical and functional differences between early-onset and late-onset adult asthma: a population-based Tasmanian Longitudinal Health Study

BACKGROUND

Differences between early-onset and late-onset adult asthma have not been comprehensively described using prospective data.

AIMS

To characterise the differences between early-onset and late-onset asthma in a longitudinal cohort study.

METHODS

The Tasmanian Longitudinal Health Study (TAHS) is a population-based cohort. Respiratory histories and spirometry were first performed in 1968 when participants were aged 7 (n=8583). The cohort was traced and resurveyed from 2002 to 2005 (n=5729 responses) and a sample, enriched for asthma and bronchitis participated in a clinical study when aged 44 (n=1389).

RESULTS

Of the entire TAHS cohort, 7.7% (95% CI 6.6% to 9.0%) had early-onset and 7.8% (95% CI 6.4% to 9.4%) late-onset asthma. Atopy and family history were more common in early-onset asthma while female gender, current smoking and low socioeconomic status were more common in late-onset asthma. The impact on lung function of early-onset asthma was significantly greater than for late-onset asthma (mean difference prebronchodilator (BD) FEV₁/FVC -2.8% predicted (-5.3 to -0.3); post-BD FEV₁FVC -2.6% predicted (-5.0 to -0.1)). However, asthma severity and asthma score did not significantly differ between groups. An interaction between asthma and smoking was identified and found to be associated with greater fixed airflow obstruction in adults with late-onset asthma. This interaction was not evident in adults with early-onset disease.

CONCLUSIONS

Early-onset and late-onset adult asthma are equally prevalent in the middle-aged population. Major phenotypic differences occur with asthma age-of-onset; while both share similar clinical manifestations, the impact on adult lung function of early-onset asthma is greater than for late-onset asthma.

Indoor Fungal Exposure and Allergic Respiratory Disease

A gathering body of evidence has repeatedly revealed associations between indoor fungi and initiation, promotion, and exacerbation of allergic respiratory disease. The relationship between the exposure and outcome are complicated by the difficulties in measuring both exposure and outcome, the multifactorial nature of the disease, and the wide range of potential confounders. New technologies are becoming available that may enable better measurement of exposure and tighter case definitions so as to build more confidence in the associations discovered. The growing strength of the evidence base will aid the design of future public health interventions and generate new hypotheses on the cause of the rapid increase in allergic respiratory disease prevalence.

Xerotolerant Cladosporium sphaerospermum Are Predominant on Indoor Surfaces Compared to Other Cladosporium Species

Indoor fungi are a major cause of cosmetic and structural damage of buildings worldwide and prolonged exposure of these fungi poses a health risk. Aspergillus, Penicillium and Cladosporium species are the most predominant fungi in indoor environments. Cladosporium species predominate under ambient conditions. A total of 123 Cladosporium isolates originating from indoor air and indoor surfaces of archives, industrial factories, laboratories, and other buildings from four continents were identified by sequencing the internal transcribed spacer (ITS), and a part of the translation elongation factor 1α gene (TEF) and actin gene (ACT). Species from the Cladosporium sphaerospermum species complex were most predominant representing 44.7% of all isolates, while the Cladosporium cladosporioides and Cladosporium herbarum species complexes represented 33.3% and 22.0%, respectively. The contribution of the C. sphaerospermum species complex was 23.1% and 58.2% in the indoor air and isolates from indoor surfaces, respectively. Isolates from this species complex showed growth at lower water activity (≥ 0.82) when compared to species from the C. cladosporioides and C. herbarum species complexes (≥ 0.85). Together, these data indicate that xerotolerance provide the C. sphaerospermum species complex advantage in colonizing indoor surfaces. As a consequence, C. sphaerospermum are proposed to be the most predominant fungus at these locations under ambient conditions. Findings are discussed in relation to the specificity of allergy test, as the current species of Cladosporium used to develop these tests are not the predominant indoor species.

Indoor fungal diversity and asthma: a meta-analysis and systematic review of risk factors

BACKGROUND

Indoor dampness increases the risk of indoor fungal growth. A complex interaction between occupant behaviors and the built environment are thought to affect indoor fungal concentrations and species diversity, which are believed to increase the risk of having asthma, exacerbation of asthma symptoms, or both. To date, no systematic review has investigated this relationship.

OBJECTIVE

This review aims to assess the relationship between exposure to indoor fungi identified to the genera or species level on asthma outcomes in children and adults.

METHODS

Ten databases were systematically searched on April 18, 2013, and limited to articles published since 1990. Reference lists were independently screened by 2 reviewers, and authors were contacted to identify relevant articles. Data were extracted from included studies meeting our eligibility criteria by 2 reviewers and quality assessed by using the Newcastle-Ottawa scale designed for assessment of case-control and cohort studies.

RESULTS

Cladosporium, Alternaria, Aspergillus, and Penicillium species were found to be present in higher concentrations in homes of asthmatic participants. Exposure to Penicillium, Aspergillus, and Cladosporium species were found to be associated with increased risk of reporting asthma symptoms by a limited number of studies. The presence of Cladosporium, Alternaria, Aspergillus, and Penicillium species increased the exacerbation of current asthma symptoms by 36% to 48% compared with those exposed to lower concentrations of these fungi, as shown by using random-effect estimates. Studies were of medium quality and showed medium-high heterogeneity, but evidence concerning the specific role of fungal species was limited.

CONCLUSION

Longitudinal studies assessing increased exposure to indoor fungi before the development of asthma symptoms suggests that Penicillium, Aspergillus, and Cladosporium species pose a respiratory health risk in susceptible populations. Increased exacerbation of current asthma symptoms in children and adults were associated with increased levels of Penicillium, Aspergillus, Cladosporium, and Alternaria species, although further work should consider the role of fungal diversity and increased exposure to other fungal species.

Respiratory health in home and leisure pursuits

Many home-based and leisure activities can generate hazardous respirable exposures. Routine domestic activities and a variety of hobbies, avocations, and leisure pursuits have been associated with a spectrum of respiratory tract disorders. Indoor environments present a special risk for high-intensity exposures and adverse health effects. There are important knowledge gaps regarding the prevalence of specific health hazards within and across communities, exposure-response effects, population and individual susceptibilities, best management strategies, the adverse health effects of mixed exposures, and long-term clinical outcomes following exposures. The home environment presents special health risks that should be part of the health assessment.

Identity of the fungal species present in the homes of asthmatic children

BACKGROUND

Fungal exposures are believed to play an important role in the development of asthma and atopy, accounting for increased asthmatic symptoms and severe asthma exacerbation. Indoor fungal species vary both in taxa and concentration in different residences and in different regions.

OBJECTIVES

We explored the fungal species spectrum in 88 homes with at least one asthmatic child in the Middle West region of the United States mostly during late spring and fall season in comparison with 85 homes that did not contain an asthmatic child during flu season.

METHODS

The average fungal spore counts per cubic metre of air in the bedroom of the enrolled child, the main living spaces and outdoor environments, and the culturable fungal colony-forming units per cubic metre of air samples in the main living space from each home were measured.

RESULTS

The results indicated that Cladosporium, Penicillium, Aspergillus, Basidiospores, Epicoccum and Pithomyces were found in more asthmatic homes than in homes without an asthmatic child or existed in higher concentration in asthmatic homes than in homes without an asthmatic child even after adjusting outdoor spore concentration. The results for culturable fungal species confirmed most of these findings even after adjusting for seasonal factors. Although Alternaria was commonly found in both kinds of homes, there was no significant difference in detection rate or concentration of Alternaria between asthmatic homes and homes without an asthmatic child by either spore counting or culturable airborne detection.

CONCLUSION AND CLINICAL RELEVANCE

Since many allergens have been identified in these fungal species, identifying and controlling these fungal species in asthmatic homes might be expected to improve asthma care and benefit asthmatic children.

Residential dampness and molds and the risk of developing asthma: a systematic review and meta-analysis

CONTEXT

Studies from different geographical regions have assessed the relations between indoor dampness and mold problems and the risk of asthma, but the evidence has been inconclusive.

OBJECTIVE

To assess the relations between indicators of indoor dampness and mold problems and the risk of developing new asthma, and to investigate whether such relations differ according to the type of exposure.

DATA SOURCES

A systematic literature search of PubMed database from 1990 through March 2012 and the reference lists of recent reviews and of relevant articles identified in our search.

STUDY SELECTION

Cohort/longitudinal and incident case-control studies assessing the relation between mold/dampness and new asthma were included.

DATA EXTRACTION

Three authors independently evaluated eligible articles and extracted relevant information using a structured form.

SYNTHESIS

SIXTEEN STUDIES WERE INCLUDED: 11 cohort and 5 incident case-control studies. The summary effect estimates (EE) based on the highest and lowest estimates for the relation between any exposure and onset of asthma were for the highest estimates 1.48 (95% confidence interval [CI] 1.23-1.78, random-effects model, Q-statistic 38.75 (16), P = 0.001) ; and for the lowest estimates: 1.27 (95% CI 1.06-1.53, random-effects model, Q-statistic 38.12 (16), P = 0.000) [corrected].The summary effect estimates were significantly elevated for dampness (fixed-effects model: EE 1.33, 95% CI 1.12-1.56, Q-statistic 8.22 (9), P = 0.413), visible mold (random-effects model; EE 1.29, 95% CI 1.04-1.60, 30.30 (12), P = 0.001), and mold odor (random-effects model; EE 1.73, 95% CI 1.19-2.50, Q-statistics 14.85 (8), P = 0.038), but not for water damage (fixed-effects model; EE 1.12, 95% CI 0.98-1.27). Heterogeneity was observed in the study-specific effect estimates.

CONCLUSION

The evidence indicates that dampness and molds in the home are determinants of developing asthma. The association of the presence of visible mold and especially mold odor to the risk of asthma points towards mold-related causal agents.

Respiratory and allergic health effects of dampness, mold, and dampness-related agents: a review of the epidemiologic evidence

OBJECTIVES

Many studies have shown consistent associations between evident indoor dampness or mold and respiratory or allergic health effects, but causal links remain unclear. Findings on measured microbiologic factors have received little review. We conducted an updated, comprehensive review on these topics.

DATA SOURCES

We reviewed eligible peer-reviewed epidemiologic studies or quantitative meta-analyses, up to late 2009, on dampness, mold, or other microbiologic agents and respiratory or allergic effects.

DATA EXTRACTION

We evaluated evidence for causation or association between qualitative/subjective assessments of dampness or mold (considered together) and specific health outcomes. We separately considered evidence for associations between specific quantitative measurements of microbiologic factors and each health outcome.

DATA SYNTHESIS

Evidence from epidemiologic studies and meta-analyses showed indoor dampness or mold to be associated consistently with increased asthma development and exacerbation, current and ever diagnosis of asthma, dyspnea, wheeze, cough, respiratory infections, bronchitis, allergic rhinitis, eczema, and upper respiratory tract symptoms. Associations were found in allergic and nonallergic individuals. Evidence strongly suggested causation of asthma exacerbation in children. Suggestive evidence was available for only a few specific measured microbiologic factors and was in part equivocal, suggesting both adverse and protective associations with health.

CONCLUSIONS

Evident dampness or mold had consistent positive associations with multiple allergic and respiratory effects. Measured microbiologic agents in dust had limited suggestive associations, including both positive and negative associations for some agents. Thus, prevention and remediation of indoor dampness and mold are likely to reduce health risks, but current evidence does not support measuring specific indoor microbiologic factors to guide health-protective actions.

Preventing asthma exacerbations: what are the targets?

Exacerbations of asthma are the main cause of asthma morbidity. They induce acute respiratory failure, and sometimes death. Two immunological signals acting in synergy are necessary for inducing asthma exacerbations. The first, triggered by allergens and/or unknown agents leads to the chronic Th2 inflammation characteristic of asthma. The second, caused by either viral infection, allergens, pollutants or a combination of these, results in an acute Th1 and Th2 inflammation precipitating symptoms. In both, innate and adaptive immunities are involved, providing a series of potential targets for therapy. Molecules associated to the first, chronic inflammation constitute targets for preventing therapies, when these related to the second, acute signal provide the rationale for curative treatments. Toll like receptors and bronchial epithelial cell-derived cytokines, engaged upstream of inflammation constitute interesting candidates for future treatments. The great heterogeneity of asthma has to be taken into account when considering targets for therapy to identify clusters of responders and nonresponders, and an integrative system biology approach will be necessary to go further.

The Human Lung Microbiome

The human lower respiratory tract is considered sterile in normal healthy individuals (Flanagan et al., 2007; Speert, 2006) despite the fact that every day we breathe in multiple microorganisms present in the air and aspirate thousands of organisms from the mouth and nasopharynx. This apparent sterility is maintained by numerous interrelated components of the lung physical structures such as the mucociliary elevator and components of the innate and adaptive immune systems (discussed below) (reviewed in (Diamond et al., 2000; Gerritsen, 2000)). However, it is possible that the observed sterility might be a result of the laboratory practices applied to study the flora of the lungs. Historically, researchers faced with a set of diseases characterized by a changing and largely cryptic lung microbiome have lacked tools to study lung ecology as a whole and have concentrated on familiar, cultivatable candidate pathogens.

Visually observed mold and moldy odor versus quantitatively measured microbial exposure in homes

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.

Recent advances in pediatric asthma treatment

Although wheezing illness is at its most prevalent in infancy and early childhood, its self-limiting nature in the majority poses considerable challenges in offering a long-term prognosis and in initiating long-term prophylaxis. Many of the established treatments in adults have not been adequately assessed in children. Evidence is also emerging for a number of different wheezing syndromes, several of which do not to respond well to currently available medicines. Much research interest is being directed to underlying changes within the airway that appear to be independent of allergic mechanisms and that may lead to novel therapeutic approaches. The aim of this review is to restate and update current best-practice based on evidence, to encourage effective and safe use of asthma medication in children and to point to areas of ongoing research that are likely to influence management decisions in the near future.

Major mite allergen Der f 1 concentration is reduced in buildings with improved energy performance

BACKGROUND

Environmental conditions play a crucial role in mite growth, and optimal environmental control is key in the prevention of airway inflammation in chronic allergic rhinoconjunctivitis or asthma.

OBJECTIVE

To evaluate the relationship between building energy performance and indoor mite allergen concentration in a cross-sectional study.

METHODS

Major allergen concentration (Der f 1, Der p 1, mite group 2, Fel d 1 and Bla g 2) was determined by quantitative dot blot analysis from mattress and carpet dust samples in five buildings designed for low energy use (LEB) and in six control buildings (CB). Inhabitants had received 4 weeks prior to mite measurement a personal validated questionnaire related to the perceived state of health and comfort of living.

RESULTS

Cumulative mite allergen concentration (with Der f 1 as the major contributor) was significantly lower in LEB as compared with CB both in mattresses and in carpets. In contrast, the two categories of buildings did not differ in Bla g 2 and Fel d 1 concentration, in the amount of dust and airborne mould collected. Whereas temperature was higher in LEB, relative humidity was significantly lower than in CB. Perceived overall comfort was better in LEB.

CONCLUSIONS

Major mite allergen Der f 1 preferentially accumulates in buildings not specifically designed for low energy use, reaching levels at risk for sensitization. We hypothesize that controlled mechanical ventilation present in all audited LEB may favour lower air humidity and hence lower mite growth and allergen concentration, while preserving optimal perceived comfort.

The utility of antifungal agents for asthma

PURPOSE OF REVIEW

Recent work demonstrates that patients with refractory asthma are likely to be sensitized to environmental fungi and that specific antifungal treatments may be of benefit to this group.

RECENT FINDINGS

The relationships among fungal sensitization, exposure and asthma severity are imperfectly understood. Exposure to environmental fungi occurs ubiquitously and there is emerging evidence that internal airways colonization could be a source of ongoing exposure. Antifungal treatments appear to improve asthma-related quality of life. Such treatments are generally well tolerated but there are potential side-effects. The mechanisms behind the clinical improvements are not yet fully established.

SUMMARY

Antifungal treatments are used in some centres for patients with refractory asthma. Further research needs to explore the questions of patient selection, optimum duration of therapy and the prediction and management of azole-corticosteroid drug interactions. Advances in our understanding of the fungal molecular allergome and in our understanding of the allergic importance of small hyphal fragments may help to more precisely define the relationships among fungal sensitization, exposure and asthma severity.

Severe asthma with fungal sensitization: a case report and review of literature

There is a substantial body of evidence supporting an association between asthma severity and fungal exposure and sensitization. Fungal allergens are a recognized risk factor for severe asthma. We describe the case of a 44-year-old asthmatic whose asthma control deteriorated after moving to a new flat with walls covered in mould. Allergic bronchopulmonary aspergillosis was excluded. Although sensitization to Candida was demonstrated by a positive Candida-specific radioallergosorbent test, the patient did not entirely satisfy the criteria for a diagnosis of allergic bronchopulmonary candidiasis. The patient's asthma control improved after engaging in a monthly washing regimen of the walls. This case further demonstrates the association between fungal sensitization and asthma severity. The term severe asthma with fungal sensitization has been recently coined to describe this phenomenon.

Symptoms after mould exposure including Stachybotrys chartarum, and comparison with darkroom disease

BACKGROUND

Mould-attributed symptoms have included features which overlap with unexplained syndromes such as sick building syndrome.

OBJECTIVES

We describe questionnaire and chart review findings in patients following exposure to moulds which include Stachybotrys and compare responses with two control groups.

METHODS

Thirty-two patients presented with symptoms attributed to mould exposures. Exposure identification for 25 patients had reported S tachybotrys chartarum as well as other mould (Aspergillus, Penicillium), 88% at work. The remaining seven had professionally visualized or self-reported/photographic exposure evidence only. A chart review was performed and a follow-up with a questionnaire, including questions on current health status, and nonspecific symptoms.

RESULTS

Cough, shortness of breath and chest tightness (at presentation) were reported in 79%, 70% and 64%, respectively, and persisted >6 weeks in 91%. Skin test(s) were positive to fungal extract(s) in 30%. Seventeen returned questionnaires were obtained 3.1 (SD 0.5) years after the initial clinic assessment. Among this subgroup, persisting asthma-like symptoms and symptoms suggestive of sick building syndrome were frequent, and similar to a group previously assessed for darkroom disease among medical radiation technologists. The mould-exposed group more commonly reported they were bothered when walking in a room with carpets, complained of a chemical or metallic taste in their mouth, and had problems in concentration when compared with a control physiotherapist group (P < 0.005).

CONCLUSIONS

Although only a minority with health concerns from indoor mould exposure had demonstrable mould-allergy, a significant proportion had asthma-like symptoms. Other symptoms were also common and persistent after the initial implicated exposure.

Association of Atopy to Asthma Severity and Medication Use in Children

The importance of aeroallergens as triggers for asthma is well recognized, but the relationship between asthma severity and atopic profiles in childhood has not been elucidated. This study assessed the relationship of allergen sensitization to asthma severity in a study of 114 asthmatic children followed for 8 weeks in three Southern California areas. Increased controller medication and beta-agonist use were positively associated with number of positive skin tests and allergy to mold and pollens. Mold was associated with increased asthma symptoms. Degree of atopy and reactivity to mold and pollens plays a significant role in asthma severity in asthmatic children.

Dampness and mold in the indoor environment: implications for asthma

This article presents epidemiologic findings pertinent to asthma and asthma-like symptoms in relation to exposure to dampness/mold in homes, schools, and workplaces. With regard to specific agents found in damp indoor environments that may play a role in asthma, it concentrates on mold (used synonymously with fungi) and includes some findings on bacteria. The literature on asthma in relation to dust mite or cockroach allergens is not addressed.

Early identification of atopy in the prediction of persistent asthma in children

The long-term solution to the asthma epidemic is thought to be prevention, and not treatment of established disease. Atopic asthma arises from gene-environment interactions, which mainly take place during a short period in prenatal and postnatal development. These interactions are not completely understood, and hence primary prevention remains an elusive goal. We argue that primary-care physicians, paediatricians, and specialists lack knowledge of the role of atopy in early life in the development of persistent asthma in children. In this review, we discuss how early identification of children at high risk is feasible on the basis of available technology and important for potential benefits to the children. Identification of an asthmatic child's atopic status in early life has practical clinical and prognostic implications, and sets the basis for future preventative strategies.

Asthma and allergy: short texts and recommendations of the expert conference of the French Speaking Pneumology Society (SPLF), in partnership with the French Society of Allergology and Clinical Immunology (SFAIC), the French Society of Occupational Medicine (SFMT) and the "Asthma-Allergy" association

The Asthma Plan published by the French Health Ministry in 2002, the experts conferences edited by ANAES on therapeutic education and follow-up of asthma, the inclusion of this disease in the Public Health Law have been remarkable steps in France during the last few years. The medical community, more particularly the pneumological community, has shown its commitment in the treatment of this public health problem. But allergy was not sufficiently taken into account, although it is responsible for nearly 50 to 60% cases of asthma. In most so-called developed countries the prevalence of asthma and of allergies has increased in the last twenty years. Its progress varies according to country and age group: the increased prevalence of allergy, more specifically of rhinitis and eczema, is most marked in children aged 6-7 year. The prevalence of asthma seems to have reached a plateau in certain northern countries or seems to have decreased in 13-14 year olds (Anglo-Saxon countries). There were multiple reasons, generally attributed to changes in life-style. Asthma is the result of an interaction between a genetic predisposition and the environment, where allergens are present, but also smoking. The relationships between allergy and asthma are complex. This conference discussed the various essential issues that face doctors who treat patients with asthma in their daily practice. The risk factors, the methods of exploration in children and adults and the specific treatments are, indeed, essential issues to be evaluated in a frequent pathology that interests a large number of physicians. The variety of experts is wide, representing pneumology (French Speaking Pneumology Society), the occupational medicine world (French Society of Occupational Medicine), the allergic pathology (French Society of Allergology and Clinical Immunology), and patients with the patient association "Asthma & Allergy", physicians belonging to the general medicine community, general hospitals, private hospitals and academic hospitals in France. The proposed guidelines are aimed at helping practitioners in distinguishing what is established from what remains to be demonstrated and/or assessed with respect to the different modalities for the exploration or treatment of allergic asthma.

Impact of depression and anxiety on quality of life, health behaviors, and asthma control among adults in the United States with asthma, 2006

BACKGROUND

Psychological factors such as anxiety and depression are increasingly being recognized as influencing the onset and course of asthma.

METHODS

We obtained Patient Health Questionnaire 8 depression data from 41 states and territories using the 2006 Behavioral Risk Factor Surveillance System. Heath risk behaviors, social and emotional support, life satisfaction, disability, and four health-related quality-of-life (HRQOL) questions were available for all states and territories (n = 18,856 with asthma). Five additional HRQOL questions were asked in three states (n = 1345 persons with asthma), and questions assessing asthma control were available for nine states (n = 3943 persons with asthma).

RESULTS

Persons with asthma were significantly more likely than those without asthma to have current depression (19.4% vs. 7.7%), a lifetime diagnosis of depression (30.6% vs. 14.4%), and anxiety (23.5% vs. 10.2%). For most domains examined, there was a dose-response relationship between level of depression severity and mean number of days of impaired HRQOL in the past 30 days, as well as an increased prevalence of life dissatisfaction, inadequate social support, disability, and risk behaviors, such as smoking, physical inactivity, and obesity, among those with asthma. Moreover, depression and anxiety were associated with a decreased level of asthma control, including more visits to the doctor or emergency room, inability to do usual activities, and more days of symptoms compared to those without depression or anxiety.

CONCLUSION

This research indicates that a multidimensional, integrative approach to health care should be considered when assessing patients with asthma.

Longitudinal evaluation of allergen and culturable fungal concentrations in inner-city households

To characterize seasonal variation of three allergens (dust mite, cat, and cockroach) and total culturable fungi and to explore whether residential characteristics were associated with the concentrations of these agents, floor dust was collected from 47 inner-city homes in Minneapolis, Minnesota, over a 1-year period. A longitudinal analysis of allergen and fungal concentrations was carried out using mixed-effect models. Overall, relative humidity was a better predictor of allergen concentrations over time than indoor temperature. Seasonal variation of cat and cockroach allergens was negligible compared with the variability associated with residential characteristics such as race/ethnicity, family income, and the presence of cats. Fungal concentrations showed significant seasonal variation that outweighed the variability associated with residential characteristics. Less than 30% of the dust mite allergen and cockroach allergens concentrations were above limits of detection. Observed cockroach allergen concentrations were higher in Spanish- and Somali-speaking households than in English-speaking households, while English-speaking households had significantly higher cat allergen concentrations compared with the other language groups. The ratios of within-home to between-home variance for total culturable fungi, dust mite, cockroach, and cat allergen concentrations were 2.54, 1.91, 0.55, and 0.24, respectively. This ratio is used to predict the number of repeated measurements of each allergen required to robustly estimate long-term exposure estimates such that exposure misclassification bias is kept within acceptable limits. It is not clear whether repeated measurements of dust mite and cockroach allergens are required for long-term average exposure because of the large fraction of nondetects. It is concluded that a single measurement of cat allergen is a reasonable surrogate for long-term average exposure, since repeated measurements over time were highly correlated. Total culturable fungi will require greater than nine repeated measurements for robust assessment of long-term exposures because of low correlations in fungal measures over time.

Hydrophilic fungi and ergosterol associated with respiratory illness in a water-damaged building

BACKGROUND

Damp building-related respiratory illnesses are an important public health issue.

OBJECTIVE

We compared three respiratory case groups defined by questionnaire responses [200 respiratory cases, 123 of the respiratory cases who met the epidemiologic asthma definition, and 49 of the epidemiologic asthma cases who had current physician-diagnosed asthma with post-occupancy onset] to a comparison group of 152 asymptomatic employees in an office building with a history of water damage.

METHODS

We analyzed dust samples collected from floors and chairs of 323 cases and comparisons for culturable fungi, ergosterol, endotoxin, and cat and dog allergens. We examined associations of total fungi, hydrophilic fungi (requiring water activity > or = 0.9), and ergosterol with the health outcomes using logistic regression models.

RESULTS

In models adjusted for demographics, respiratory illnesses showed significant linear exposure-response relationships to total culturable fungi [interquartile range odds ratios (IQR-OR) = 1.37-1.72], hydrophilic fungi (IQR-OR = 1.45-2.19), and ergosterol (IQR-OR = 1.54-1.60) in floor and chair dusts. Of three outcomes analyzed, current asthma with postoccupancy physician diagnosis was most strongly associated with exposure to hydrophilic fungi in models adjusted for ergosterol, endotoxin, and demographics (IQR-OR = 2.09 for floor and 1.79 for chair dusts). Ergosterol levels in floor dust were significantly associated with epidemiologic asthma independent of culturable fungi (IQR-OR = 1.54-1.55).

CONCLUSIONS

Our findings extend the 2004 conclusions of the Institute of Medicine [Human health effects associated with damp indoor environments. In: Damp Indoor Spaces and Health. Washington DC:National Academies Press, 183-269] by showing that mold levels in dust were associated with new-onset asthma in this damp indoor environment. Hydrophilic fungi and ergosterol as measures of fungal biomass may have promise as markers of risk of building-related respiratory diseases in damp indoor environments.

The associations between smoking, physical inactivity, obesity, and asthma severity in the general US population

The purpose of this study was to examine the associations between smoking, physical inactivity, obesity, and asthma severity among US adults. The magnitude of these associations was very strong. For example, those who visited an emergency room in the past year were 60% more likely than those who did not to smoke; those who used an inhaler > or =15 times in the past month (versus those who did not use an inhaler) were 90% more likely to be physically inactive; and those who had asthma symptoms all the time in the past 30 days (versus those with no symptoms) were 80% more likely to be obese.

Residential exposure to mould and dampness is associated with adverse respiratory health

BACKGROUND

Indoor exposure to mould and dampness is frequently associated with asthma symptoms with and without lung function changes. However, the mechanisms contributing to this threat to respiratory health are only partly understood.

OBJECTIVE

To investigate the contribution of recent exposure to mould and dampness in the living room or bedroom to respiratory health in a general practice-based cohort of 526 asthmatic children.

METHODS

Parents were questioned about home characteristics, including moulds and dampness. The level of asthma control was evaluated in their participating children by means of asthma symptoms, peak expiratory flow (PEF) variability, severity of airway hyperresponsiveness (AHR), and medication usage.

RESULTS

Children exposed to indoor moulds and dampness more often had severe AHR compared with non-exposed (42% vs. 16%; P< or =0.001). They also showed an increased PEF variability (11.3% vs. 8.4%; P=0.03) and, however, not significant, more frequent asthma symptoms. The use of controller medication was not significantly different between exposed and non-exposed children. After adjustment for gender, age, smoking, exposure to parental smoking, parental education, pet ownership, presence of inhalant allergy, use of controller medication, health care center, and season of study assessment, the odds ratio for severe AHR in exposed children was 3.95 [95% confidence interval (CI): 1.82-8.57].

CONCLUSION

We found a consistent association between reported moulds and dampness in the living room or the child's bedroom and an increased risk for severe AHR in a general practice-based cohort of asthmatic children, even after adjustment for gender, presence of inhalant allergy, and use of controller medication.

Associations between ambient PM2.5 concentrations and respiratory symptoms in Melbourne, 1998-2005

Particulate matter (PM) has been widely associated with adverse effects on respiratory health, both overseas and in Australia. This study aimed to investigate the impacts of ambient particles of <2.5 microm diameter (PM2.5) in Melbourne on adverse respiratory symptoms. Two cohorts of adults were recruited in 1992-1998, and completed detailed respiratory questionnaires in 1998-1999 and 2004-2005. The mean age at baseline was 37.2 years, 55% were female, and the mean time lapsed between the baseline and follow-up questionnaires was 5.2 years. PM2.5 exposure was assessed from gravimetric data and routine nephelometry at monitoring stations located centrally with respect to the residence of most participants. Daily exposures to PM2.5 were averaged over the previous 12 months and mean daily exposure was 6.8 microg/m3. Logistic regression models were used to examine associations between PM2.5 exposure and adverse respiratory symptoms. Adjustment was made for age, gender, current smoking status, and medication use, but further adjustment for atopy did not alter the results. There was insufficient variability in PM2.5 exposure among participants over the study period to provide convincing evidence for or against associations between PM2.5 and adverse respiratory symptoms.

Bronchial responsiveness in atopic adults increases with exposure to cat allergen

RATIONALE

The association of asthma with sensitization and allergen exposure is known to be complex. There have been few studies of bronchial responsiveness in relation to both risk factors in adults.

OBJECTIVES

To determine the relation of bronchial responsiveness to allergen exposure and IgE sensitization in a community study taking into account the major determinants of bronchial responsiveness in adulthood.

METHODS

Cross-sectional data were drawn from 1,884 participants in 20 centers in the European Community Respiratory Health Survey follow-up, which included measurement of house dust mite and cat allergen in mattress dust samples, and IgE sensitization to four allergens. Bronchial responsiveness to methacholine was expressed as a continuous variable, and analyzed by multiple regression.

MEASUREMENTS AND MAIN RESULTS

The trend toward greater bronchial responsiveness with increasing exposure to cat allergen was greater in those sensitized to any of the four allergens than those not sensitized (p = 0.001); there was no significant interaction between cat sensitization and Fel d 1 exposure. No trend was found with house dust mite allergen exposure. The difference in bronchial responsiveness between those exposed to the highest levels compared with the lowest was approximately -2.02 doubling doses of PD20 (95% confidence interval, -3.06 to -0.97), and nearly as great in those exposed to more moderate levels.

CONCLUSIONS

Cat allergen exposure at moderate levels may be harmful to all atopic adults. The clinical implication is that it is insufficient to test patients with asthma for cat sensitization; all atopic individuals may benefit from reduced cat exposure.

Anti-IgE and chemotherapy: a critical appraisal of treatment options for severe asthma

In this narrative review the scientific rationale for the development of a therapeutic modality for asthma based on decreasing the circulating and cell-bound levels of immunoglobulin-E (IgE) is outlined. The one drug that has so far entered clinical practice to do this is a humanised monoclonal antibody to the Fc portion of the IgE molecule, omalizumab. It is highly effective in reducing IgE blood levels and its established mode of delivery is by subcutaneous injection. The clinical trial development of omalizumab is reviewed and the published data and claims for its efficacy and role in clinical practice is critically appraised. The target group of omalizumab has become focused on severe asthmatics who are still symptomatic after being administered with high-dose inhaled corticosteroids plus long-acting beta-agonists. The strongest evidence for effect is in those with frequent severe exacerbations.

Effects on patients with asthma of eradicating visible indoor mould: a randomised controlled trial

BACKGROUND

It is not clear whether associations between respiratory symptoms and indoor mould are causal. A randomised controlled trial was conducted to see whether asthma improves when indoor mould is removed.

METHODS

Houses of patients with asthma were randomly allocated into two groups. In one group, indoor mould was removed, fungicide was applied and a fan was installed in the loft. In the control group, intervention was delayed for 12 months. Questionnaires were administered and peak expiratory flow rate was measured at baseline, 6 months and 12 months.

RESULTS

Eighty-one houses were allocated to the intervention group and 83 to the control group; 95 participants in 68 intervention houses and 87 in 63 control houses supplied follow-up information. Peak expiratory flow rate variability declined in both groups, with no significant differences between them. At 6 months, significantly more of the intervention group showed a net improvement in wheeze affecting activities (difference between groups 25%, 95% CI 3% to 47%; p = 0.028), perceived improvement of breathing (52%, 95% CI 30% to 74%; p<0.0001) and perceived reduction in medication (59%, 95% CI 35% to 81%; p<0.0001). By 12 months the intervention group showed significantly greater reductions than the controls in preventer and reliever use, and more improvement in rhinitis (24%, 95% CI 9% to 39%; p = 0.001) and rhinoconjunctivitis (20%, 95% CI 5% to 36%; p = 0.009).

CONCLUSIONS

Although there was no objective evidence of benefit, symptoms of asthma and rhinitis improved and medication use declined following removal of indoor mould. It is unlikely that this was entirely a placebo effect.