Damp housing and childhood asthma: validation of reporting of symptoms

Exposure Levels of Airborne Fungi, Bacteria, and Antibiotic Resistance Genes in Cotton Farms during Cotton Harvesting and Evaluations of N95 Respirators against These Bioaerosols

The USA is the third-leading cotton-producing country worldwide and cotton farming is common in the state of Georgia. Cotton harvest can be a significant contributor to airborne microbial exposures to farmers and nearby rural communities. The use of respirators or masks is one of the viable options for reducing organic dust and bioaerosol exposures among farmers. Unfortunately, the OSHA Respiratory Protection Standard (29 CFR Part 1910.134) does not apply to agricultural workplaces and the filtration efficiency of N95 respirators was never field-tested against airborne microorganisms and antibiotic resistance genes (ARGs) during cotton harvesting. This study addressed these two information gaps. Airborne culturable microorganisms were sampled using an SAS Super 100 Air Sampler in three cotton farms during cotton harvesting, and colonies were counted and converted to airborne concentrations. Genomic DNA was extracted from air samples using a PowerSoil^® DNA Isolation Kit. A series of comparative critical threshold (2^-ΔΔCT) real-time PCR was used to quantify targeted bacterial (16S rRNA) genes and major ARGs. Two N95 facepiece respirator models (cup-shaped and pleated) were evaluated for their protection against culturable bacteria and fungi, total microbial load in terms of surface ATP levels, and ARGs using a field experimental setup. Overall, culturable microbial exposure levels ranged between 10³ and 10⁴ CFU/m³ during cotton harvesting, which was lower when compared with bioaerosol loads reported earlier during other types of grain harvesting. The findings suggested that cotton harvesting works can release antibiotic resistance genes in farm air and the highest abundance was observed for phenicol. Field experimental data suggested that tested N95 respirators did not provide desirable >95% protections against culturable microorganisms, the total microbial load, and ARGs during cotton harvesting.

Aspergillus Section Fumigati in Firefighter Headquarters

Background: Aspergillus section Fumigati is one of the Aspergillus sections more frequently related to respiratory symptoms and by other health outcomes. This study aimed to characterize Aspergillus section Fumigati distribution in eleven firefighter headquarters (FFHs) to obtain an accurate occupational exposure assessment. Methods: A sampling approach protocol was performed using active (impaction method) and passive sampling methods (floor surfaces swabs, electrostatic dust collectors (EDCs), and settled dust). All samples were analysed by culture-based methods and passive sampling was used for molecular detection of Aspergillus section Fumigati. Results: Of all the matrices, the highest counts of Aspergillus sp. were obtained on settled dust filters (3.37% malt extract agar—MEA, 19.09% dichloran glycerol—DG18) followed by cleaning cloths (1.67% MEA; 7.07% DG18). Among the Aspergillus genus, the Fumigati section was predominant in Millipore and EDC samples in MEA (79.77% and 28.57%, respectively), and in swabs and settled dust filters in DG18 (44.76% and 30%, respectively). The Fumigati section was detected more frequently in DG18 (33.01%) compared to MEA (0.33%). The Fumigati section was observed in azole supplemented media (itraconazole and voriconazole) in several passive sampling methods employed and detected by qPCR in almost all passive samples, with EDCs being the matrix with the highest prevalence (n = 61; 67.8%). Conclusion: This study confirms that Aspergillus sp. is widespread and the Fumigati section is present in all FFHs. The presence of fungi potentially resistant to azoles in the FFHs was also observed. Further studies are needed to identify the best corrective and preventive measures to avoid this section contamination in this specific occupational environment.

Analysis of culturable airborne fungi in outdoor environments in Tianjin, China

Background

Fungal spores dispersed in the atmosphere may become cause of different pathological conditions and allergies for human beings. A number of studies have been performed to analyze the diversity of airborne fungi in different environments worldwide, and in particular in many urban areas in China. We investigated, for the first time, the diversity, concentration and distribution of airborne fungi in Tianjin city. We sampled 8 outdoor environments, using open plate method, during a whole winter season. Isolated fungi were identified by morphological and molecular analysis. Environmental factors which could influence the airborne fungi concentration (temperature, humidity, wind speed, and air pressure) were monitored and analyzed. The effect of different urban site functions (busy areas with high traffic flow and commercial activities vs. green areas) on airborne fungal diversity was also analyzed.

Results

A total of 560 fungal strains, belonging to 110 species and 49 genera of Ascomycota (80 %), Basidiomycota (18 %), and Mucoromycota (2 %) were isolated in this study. The dominant fungal genus was Alternaria (22 %), followed by Cladosporium (18.4 %), Naganishia (14.1 %), Fusarium (5.9 %), Phoma (4.11 %), and Didymella (4.8 %). A fungal concentration ranging from 0 to 3224.13 CFU m^− 3 was recorded during the whole study. Permutational multivariate analysis showed that the month was the most influential factor for airborne fungal community structure, probably because it can be regarded as a proxy of environmental variables, followed by wind speed. The two analyzed environments (busy vs. green) had no detectable effect on the air fungal community, which could be related to the relatively small size of parks in Tianjin and/or to the study season.

Conclusions

Our study shed light on the highly diverse community of airborne fungi characterizing the outdoor environments of Tianjin, and clarified the role that different environmental factors played in shaping the analyzed fungal community. The dominant presence of fungi with potential hazardous effect on human health, such as Alternaria, Cladosporium and Naganishia, deserves further attention. Our results may represent a valuable source of information for air quality monitoring, microbial pollution control, and airborne diseases prevention.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02205-2.

Microbial growth in building material samples and occupants' health in severely moisture-damaged homes

There is no commonly approved approach to detect and quantify the health-relevant microbial exposure in moisture-damaged buildings. In 39 single-family homes with severe moisture damage, we studied whether concentrations of viable microbes in building material samples are associated with health among 71 adults and 68 children, and assessed with symptoms questionnaires, exhaled NO, and peak expiratory flow (PEF) variability. Symptoms were grouped into three scores: upper respiratory symptoms, lower respiratory symptoms, and general symptoms. The homes were divided into three groups based on viable counts of fungi, actinomycetes, and total bacteria cultivated from building material samples. Highest group of actinomycete counts was associated with more general symptoms, worse perceived health, and higher daily PEF variability (aOR 12.51; 1.10-141.90 as compared to the lowest group) among adults, and with an increase in lower respiratory symptoms in children, but the confidence intervals were wide. We observed significant associations of fungal counts and total microbial score with worse perceived health in adults. No associations with exhaled NO were observed.

Indoor visible mold and mold odor are associated with new-onset childhood wheeze in a dose-dependent manner

Evidence is accumulating that indoor dampness and mold are associated with the development of asthma. The underlying mechanisms remain unknown. New Zealand has high rates of both asthma and indoor mold and is ideally placed to investigate this. We conducted an incident case-control study involving 150 children with new-onset wheeze, aged between 1 and 7 years, each matched to two control children with no history of wheezing. Each participant's home was assessed for moisture damage, condensation, and mold growth by researchers, an independent building assessor and parents. Repeated measures of temperature and humidity were made, and electrostatic dust cloths were used to collect airborne microbes. Cloths were analyzed using qPCR. Children were skin prick tested for aeroallergens to establish atopy. Strong positive associations were found between observations of visible mold and new-onset wheezing in children (adjusted odds ratios ranged between 1.30 and 3.56; P ≤ .05). Visible mold and mold odor were consistently associated with new-onset wheezing in a dose-dependent manner. Measurements of qPCR microbial levels, temperature, and humidity were not associated with new-onset wheezing. The association between mold and new-onset wheeze was not modified by atopic status, suggesting a non-allergic association.

Building-integrated agriculture: A first assessment of aerobiological air quality in rooftop greenhouses (i-RTGs)

Building-integrated rooftop greenhouse (i-RTG) agriculture has intensified in recent years, due to the growing interest in the development of new agricultural spaces and in the promotion of food self-sufficiency in urban areas. This paper provides a first assessment of the indoor dynamics of bioaerosols in an i-RTG, with the aim of evaluating biological air quality in a tomato greenhouse near Barcelona. It evaluates the greenhouse workers' exposure to airborne pollen and fungal spores in order to prevent allergy problems associated with occupational tasks. Moreover, it evaluates whether the quality of the hot air accumulated in the i-RTG is adequate for recirculation to heat the building. Daily airborne pollen and fungal spore concentrations were measured simultaneously in the indoor and outdoor environments during the warm season. A total of 4,924pollengrains/m³ were observed in the i-RTG, with a peak of 334pollengrains/m³day, and a total of 295,038 fungal spores were observed, reaching a maximum concentration of 26,185spores/m³day. In general, the results showed that the most important source of pollen grains and fungal spores observed indoors was the outdoor environment. However, Solanaceae pollen and several fungal spore taxa, such as the allergenic Aspergillus/Penicillium, largely originated inside the greenhouses or were able to colonize the indoor environment under favourable growing conditions. Specific meteorological conditions and agricultural management tasks are related to the highest observed indoor concentrations of pollen grains and fungal spores. Therefore, preventive measures have been suggested in order to reduce or control the levels of bioaerosols indoors (to install a system to interrupt the recirculation of air to the building during critical periods or to implement appropriate air filters in ventilation air ducts). This first evaluation could help in making decisions to prevent the development of fungal diseases, specifically those due to Oidium and Torula.

Building dampness and mold in European homes in relation to climate, building characteristics and socio-economic status: The European Community Respiratory Health Survey ECRHS II

We studied dampness and mold in homes in relation to climate, building characteristics and socio-economic status (SES) across Europe, for 7127 homes in 22 centers. A subsample of 3118 homes was inspected. Multilevel analysis was applied, including age, gender, center, SES, climate, and building factors. Self-reported water damage (10%), damp spots (21%), and mold (16%) in past year were similar as observed data (19% dampness and 14% mold). Ambient temperature was associated with self-reported water damage (OR=1.63 per 10°C; 95% CI 1.02-2.63), damp spots (OR=2.95; 95% CI 1.98-4.39), and mold (OR=2.28; 95% CI 1.04-4.67). Precipitation was associated with water damage (OR=1.12 per 100 mm; 95% CI 1.02-1.23) and damp spots (OR=1.11; 95% CI 1.02-1.20). Ambient relative air humidity was not associated with indoor dampness and mold. Older buildings had more dampness and mold (P<.001). Manual workers reported less water damage (OR=0.69; 95% CI 0.53-0.89) but more mold (OR=1.27; 95% CI 1.03-1.55) as compared to managerial/professional workers. There were correlations between reported and observed data at center level (Spearman rho 0.61 for dampness and 0.73 for mold). In conclusion, high ambient temperature and precipitation and high building age can be risk factors for dampness and mold in homes in Europe.

Aspergillus species in indoor environments and their possible occupational and public health hazards

The genus Aspergillus, which consists of a few hundred opportunistic mold species found in various climatic conditions, causes diseases including localized infections, fatal diseases, allergic responses, and inhaled conidia in humans. Herein, we present an overview of the most common diseases and allergic infections caused by Aspergillus species and their associated health hazards in various indoor environments worldwide.

Remediating buildings damaged by dampness and mould for preventing or reducing respiratory tract symptoms, infections and asthma

BACKGROUND

Dampness and mould in buildings have been associated with adverse respiratory symptoms, asthma and respiratory infections of inhabitants. Moisture damage is a very common problem in private houses, workplaces and public buildings such as schools.

OBJECTIVES

To determine the effectiveness of repairing buildings damaged by dampness and mould in order to reduce or prevent respiratory tract symptoms, infections and symptoms of asthma.

SEARCH METHODS

We searched CENTRAL (2014, Issue 10), MEDLINE (1951 to November week 1, 2014), EMBASE (1974 to November 2014), CINAHL (1982 to November 2014), Science Citation Index (1973 to November 2014), Biosis Previews (1989 to June 2011), NIOSHTIC (1930 to March 2014) and CISDOC (1974 to March 2014).

SELECTION CRITERIA

Randomised controlled trials (RCTs), cluster-RCTs (cRCTs), interrupted time series studies and controlled before-after (CBA) studies of the effects of remediating dampness and mould in a building on respiratory symptoms, infections and asthma.

DATA COLLECTION AND ANALYSIS

Two authors independently extracted data and assessed the risk of bias in the included studies.

MAIN RESULTS

We included 12 studies (8028 participants): two RCTs (294 participants), one cRCT (4407 participants) and nine CBA studies (3327 participants). The interventions varied from thorough renovation to cleaning only.Repairing houses decreased asthma-related symptoms in adults (among others, wheezing (odds ratio (OR) 0.64; 95% confidence interval (CI) 0.55 to 0.75) and respiratory infections (among others, rhinitis (OR 0.57; 95% CI 0.49 to 0.66), two studies, moderate-quality evidence). For children, we did not find a difference between repaired houses and receiving information only, in the number of asthma days or emergency department visits because of asthma (one study, moderate-quality evidence).One CBA study showed very low-quality evidence that after repairing a mould-damaged office building, asthma-related and other respiratory symptoms decreased. In another CBA study, there was no difference in symptoms between full or partial repair of houses.For children in schools, the evidence of an effect of mould remediation on respiratory symptoms was inconsistent and out of many symptom measures only respiratory infections might have decreased after the intervention. For staff in schools, there was very low-quality evidence that asthma-related and other respiratory symptoms in mould-damaged schools were similar to those of staff in non-damaged schools, both before and after intervention.

AUTHORS' CONCLUSIONS

We found moderate to very low-quality evidence that repairing mould-damaged houses and offices decreases asthma-related symptoms and respiratory infections compared to no intervention in adults. There is very low-quality evidence that although repairing schools did not significantly change respiratory symptoms in staff, pupils' visits to physicians due to a common cold were less frequent after remediation of the school. Better research, preferably with a cRCT design and with more validated outcome measures, is needed.

Can economic deprivation protect health? Paradoxical multilevel effects of poverty on Hispanic children's wheezing

Prior research suggests that economic deprivation has a generally negative influence on residents’ health. We employ hierarchical logistic regression modeling to test if economic deprivation presents respiratory health risks or benefits to Hispanic children living in the City of El Paso (Texas, USA) at neighborhood- and individual-levels, and whether individual-level health effects of economic deprivation vary based on neighborhood-level economic deprivation. Data come from the US Census Bureau and a population-based survey of El Paso schoolchildren. The dependent variable is children’s current wheezing, an established respiratory morbidity measure, which is appropriate for use with economically-deprived children with an increased likelihood of not receiving a doctor’s asthma diagnosis. Results reveal that economic deprivation (measured based on poverty status) at both neighborhood- and individual-levels is associated with reduced odds of wheezing for Hispanic children. A sensitivity analysis revealed similar significant effects of individual- and neighborhood-level poverty on the odds of doctor-diagnosed asthma. Neighborhood-level poverty did not significantly modify the observed association between individual-level poverty and Hispanic children’s wheezing; however, greater neighborhood poverty tends to be more protective for poor (as opposed to non-poor) Hispanic children. These findings support a novel, multilevel understanding of seemingly paradoxical effects of economic deprivation on Hispanic health.

Associations between selected allergens, phthalates, nicotine, polycyclic aromatic hydrocarbons, and bedroom ventilation and clinically confirmed asthma, rhinoconjunctivitis, and atopic dermatitis in preschool children

Previous studies, often using data from questionnaires, have reported associations between various characteristics of indoor environments and allergic disease. The aim of this study has been to investigate possible associations between objectively assessed indoor environmental factors and clinically confirmed asthma, rhinoconjunctivitis, and atopic dermatitis. The study is a cross-sectional case-control study of 500 children aged 3-5 years from Odense, Denmark. The 200 cases had at least two parentally reported allergic diseases, while the 300 controls were randomly selected from 2835 participating families. A single physician conducted clinical examinations of all 500 children. Children from the initially random control group with clinically confirmed allergic disease were subsequently excluded from the control group and admitted in the case group, leaving 242 in the healthy control group. For most children, specific IgE's against various allergens were determined. In parallel, dust samples were collected and air change rates were measured in the children's bedrooms. The dust samples were analyzed for phthalate esters, polycyclic aromatic hydrocarbons (PAH), nicotine, and various allergens. Among children diagnosed with asthma, concentrations of nicotine were higher (P < 0.05) and cat allergens were lower (P < 0.05) compared with the healthy controls; air change rates were lower for those sensitized (specific IgE+) compared with those not sensitized (specific IgE-, P < 0.05); and dust mite allergens were higher for specific IgE+ cases compared with healthy controls (P < 0.05). When disease status was based solely on questionnaire responses (as opposed to physician diagnosis), significant associations were found between di(2-ethylhexyl) phthalate (DEHP) and dog allergens in dust and current wheeze.

Neighborhood context and the Hispanic health paradox: differential effects of immigrant density on children׳s wheezing by poverty, nativity and medical history

Prior research suggests that immigrant enclaves provide respiratory health benefits for US Hispanic residents. We test if immigrant enclaves provide differential respiratory health benefits for Hispanic children in El Paso (Texas) based on individual-level factors. Results reveal that higher neighborhood immigrant density is associated with reduced odds of wheezing, but that the protective immigrant enclave effect is modified by poverty, general health status, body mass index (BMI), and caretaker nativity. Higher immigrant density is significantly more protective for poor children and those with foreign-born caretakers; conversely, it is significantly less protective for children in worse health and those with higher BMI. These findings foster a novel understanding of how immigrant enclaves may be differentially protective for Hispanic children based on individual-level factors.

Housing and child health

The connection between housing and health is well established. Physical, chemical, and biological aspects of the child's home, such as cleanliness, moisture, pests, noise, accessibility, injury risks, and other forms of housing environmental quality, all have the potential to influence multiple aspects of the health and development of children. Basic sanitation, reduced household crowding, other improvements in housing and expanded, and improved housing regulations have led to advances in children's health. For example, lead poisoning prevention policies have profoundly reduced childhood lead exposure in the United States. This and many other successes highlight the health benefits for families, particularly children, by targeting interventions that reduce or eliminate harmful exposures in the home. Additionally, parental mental health problems, food insecurity, domestic violence, and the presence of guns in children's homes all are largely experienced by children in their homes, which are not as yet considered part of the Healthy Homes agenda. There is a large movement and now a regulatory structure being put in place for healthy housing, which is becoming closely wedded with environmental health, public health, and the practice of pediatrics. The importance of homes in children's lives, history of healthy homes, asthma, and exposures to lead, carbon monoxide, secondhand/thirdhand smoke, radon, allergy triggers is discussed, as well as how changes in ambient temperature, increased humidity, poor ventilation, water quality, infectious diseases, housing structure, guns, electronic media, family structure, and domestic violence all affect children's health.

The effect of mold sensitization and humidity upon allergic asthma

INTRODUCTION

Humidity is commonly associated with increased airway hyperresponsiveness in asthma.

OBJECTIVE

To examine mold sensitization in patients with allergic asthma or allergic rhinitis and self-reports of humidity as exacerbating factors of clinical symptoms.

METHODS

A retrospective, cross-sectional study at a University hospital outpatient allergy and asthma clinic was performed. A total of 106 patients with either allergic asthma or allergic rhinitis completed standard prick-puncture skin testing with 17 allergens and controls and completed standardized forms addressing trigger factors for clinical symptoms.

RESULTS

Allergic asthmatics sensitized to Cladosporium were more likely to have a more severe asthma severity class (odds ratio = 4.26, confidence interval = 1.30-16.93). Sensitization to Alternaria, Cladosporium, Helminthosporium, Aspergillus and Dermatophagoides pteronyssinus in asthma was associated with higher likelihood for previous hospitalization, while sensitization to Cladosporium, Helminthosporium, Aspergillus, Dermatophagoides pteronyssinus and cockroach in asthma was associated with higher likelihood of having reduced pulmonary function based on forced expiratory volume in 1s. Furthermore, allergic asthmatics more commonly reported humidity as an exacerbating factor of symptoms than did patients only with allergic rhinitis (68.42% vs 42.86%, respectively; P < 0.05).

CONCLUSION

Mold sensitization is highly associated with more severe asthma, while humidity is more of an exacerbating factor in patients with allergic asthma as compared with allergic rhinitis alone. Further delineation between mold sensitization and humidity is needed to determine whether these are independent factors in asthma.

Airborne microorganisms, endotoxin, and (1→3)-β-D-glucan exposure in greenhouses and assessment of respiratory symptoms among workers

OBJECTIVES

Greenhouse operations are an important sector of the horticulture industry, also known as the Green Industry. The objectives of this study were (i) to investigate exposure levels to airborne culturable fungi, bacteria (total culturable bacteria and actinomycetes), endotoxin, and (1→3)-β-D-glucan in three Midwest greenhouses during summer and winter using multiple exposure assessment methods; (ii) characterize the load of microorganisms on greenhouse floors and determine potential microbial source strengths of the floors for aerosolizing microbial biocontaminants, and (iii) to estimate the prevalence of rhinitis, wheezing, asthma, and other respiratory symptoms/conditions among greenhouse workers.

METHODS

Stationary inhalable aerosol samples were collected from each greenhouse using Button Inhalable Aerosol Samplers. Control samples were collected from offices and nearby outdoor locations. A microbial source strength tester was used to examine the aerosolization potential of microbial contaminants from greenhouse floors. Additionally, surface samples were collected by sterile cotton swabs. Temperature, relative humidity, and wind velocity were recorded. Airborne culturable fungi, bacteria, and actinomycetes were analyzed in the extracts from field samples by cultivation in nutrient agar media. Endotoxin and (1→3)-β-D-glucan in the extracts from field samples were analyzed by specific kinetic chromogenic Limulus amebocyte lysate assays. The prevalence of respiratory symptoms among greenhouse workers (n = 35) and control subjects (office workers; n = 14) was estimated with a standardized questionnaire.

RESULTS AND CONCLUSIONS

The collected data indicate that workers employed in Midwest greenhouses may be exposed to elevated levels of inhalable culturable microorganisms (fungi and bacteria collectively on the order of 10(2)-10(5) CFU m(-3)), endotoxin (10(1)-10(3) EU m(-3)), and (1→3)-β-D-glucan (10(1)-10(2) ng m(-3)). Seasonal variations were observed for some bioaerosol components. The prevalence of self-reported respiratory symptoms was generally higher among greenhouse workers compared to controls; however, the differences were not statistically significant, likely due to the relatively low statistical power of the study.

Association of residential dampness and mold with respiratory tract infections and bronchitis: a meta-analysis

BACKGROUND

Dampness and mold have been shown in qualitative reviews to be associated with a variety of adverse respiratory health effects, including respiratory tract infections. Several published meta-analyses have provided quantitative summaries for some of these associations, but not for respiratory infections. Demonstrating a causal relationship between dampness-related agents, which are preventable exposures, and respiratory tract infections would suggest important new public health strategies. We report the results of quantitative meta-analyses of published studies that examined the association of dampness or mold in homes with respiratory infections and bronchitis.

METHODS

For primary studies meeting eligibility criteria, we transformed reported odds ratios (ORs) and confidence intervals (CIs) to the log scale. Both fixed and random effects models were applied to the log ORs and their variances. Most studies contained multiple estimated ORs. Models accounted for the correlation between multiple results within the studies analyzed. One set of analyses was performed with all eligible studies, and another set restricted to studies that controlled for age, gender, smoking, and socioeconomic status. Subgroups of studies were assessed to explore heterogeneity. Funnel plots were used to assess publication bias.

RESULTS

The resulting summary estimates of ORs from random effects models based on all studies ranged from 1.38 to 1.50, with 95% CIs excluding the null in all cases. Use of different analysis models and restricting analyses based on control of multiple confounding variables changed findings only slightly. ORs (95% CIs) from random effects models using studies adjusting for major confounding variables were, for bronchitis, 1.45 (1.32-1.59); for respiratory infections, 1.44 (1.31-1.59); for respiratory infections excluding nonspecific upper respiratory infections, 1.50 (1.32-1.70), and for respiratory infections in children or infants, 1.48 (1.33-1.65). Little effect of publication bias was evident. Estimated attributable risk proportions ranged from 8% to 20%.

CONCLUSIONS

Residential dampness and mold are associated with substantial and statistically significant increases in both respiratory infections and bronchitis. If these associations were confirmed as causal, effective control of dampness and mold in buildings would prevent a substantial proportion of respiratory infections.

Confirmed moisture damage at home, respiratory symptoms and atopy in early life: a birth-cohort study

OBJECTIVES

Most previous studies on the association between moisture or mold problems in the home and respiratory symptoms in children were cross-sectional and based on self-reported exposure. The aim of this study was to evaluate the impact of objectively observed moisture damage and visible mold in the homes on early-life respiratory morbidity and atopic sensitization in a birth cohort.

METHODS

Building inspection was performed by building engineers in the homes of 396 children, and the children were followed up with questionnaires from birth to the age of 18 months. Specific immunoglobulin E levels were measured at the age of 1 year.

RESULTS

Doctor-diagnosed wheezing was associated with the severity of moisture damage in the kitchen and with visible mold in the main living area and especially in the bedroom of the child. The risk for parent-reported wheezing apart from cold increased with the severity of moisture damage in the kitchen. Moisture damage in the bathrooms or other interior spaces had no significant association with wheezing. No significant associations were observed for other end points, such as cough, or respiratory infections. There was a suggestion for an increased risk for sensitization to cat dander linked with moisture and mold exposure.

CONCLUSIONS

This birth-cohort study supports previous observations that moisture mold problems in the kitchen and in the main living area increase the risk for wheezing in early childhood. The results underline the importance of assessing separately the health effects of moisture and mold problems in different areas of the home.

Respiratory inflammatory responses among occupants of a water-damaged office building

The National Institute for Occupational Safety and Health (NIOSH) received a request for evaluation of a water-damaged office building which housed approximately 1300 employees. Workers reported respiratory conditions that they perceived to be building related. We hypothesized that these symptoms were associated with airways inflammation. To test this hypothesis, we assessed airways inflammation in employees using exhaled breath condensate (EBC) and the fraction of exhaled nitric oxide (FENO). In September 2001, a health questionnaire was offered to all employees. Based on this questionnaire, NIOSH invited 356 symptomatic and asymptomatic employees to participate in a medical survey. In June 2002, these employees were offered questionnaire, spirometry, methacholine challenge test, allergen skin prick testing, EBC and FENO. FENO or EBC were completed by 239 participants. As smoking is highly related to the measurements that we used in this study, we included only the 207 current non-smokers in the analyses. EBC interleukin-8 (IL-8) levels, but not nitrite, were significantly higher among workers with respiratory symptoms and in the physician-diagnosed asthmatic group. Of the analyses assessed, EBC IL-8 showed the most significant relationship with a number of symptoms and physician-diagnosed asthma.

PRACTICAL IMPLICATIONS

Implementation of exhaled breath condensate and exhaled nitric oxide in indoor air quality problems.

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.

Effects of moisture damage and renovation on microbial conditions and pupils' health in two schools--a longitudinal analysis of five years

Airborne microbes and pupils' symptoms were monitored in a moisture-damaged (index) school and a reference school for five consecutive years. These surveys were carried out in two separate years before the renovation of the index school, during the renovation, and one and two years after the renovation. Microbial concentrations were higher in the index school than those in the reference school before and during renovation, but afterwards, the levels decreased to the level of the reference school. The effect of remediation was seen as an altered mycobiota in the index school. Year-to-year variation of microbial concentrations, probably due to climatic factors, caused a peak in both schools but their difference remained. Several symptoms were more prevalent in the moisture-damaged school than in the reference school, but the differences disappeared during the renovations. These results emphasize the importance of using a reference building in assessing the microbial conditions of a moisture damaged building. Furthermore, microbial concentrations reflected well the technical condition of the construction, but the reported symptoms of the occupants did not strictly follow the timely fluctuation in microbial conditions.

Spectrum of noninfectious health effects from molds

Molds are multicellular fungi that are ubiquitous in outdoor and indoor environments. For humans, they are both beneficial (for the production of antimicrobial agents, chemotherapeutic agents, and vitamins) and detrimental. Exposure to mold can occur through inhalation, ingestion, and touching moldy surfaces. Adverse health effects may occur through allergic, infectious, irritant, or toxic processes. The cause-and-effect relationship between mold exposure and allergic and infectious illnesses is well known. Exposures to toxins via the gastrointestinal tract also are well described. However, the cause-and-effect relationship between inhalational exposure to mold toxins and other untoward health effects (eg, acute idiopathic pulmonary hemorrhage in infants and other illnesses and health complaints) is controversial and requires additional investigation. In this report we examine evidence of fungal-related illnesses and the unique aspects of mold exposure to children. Mold-remediation procedures are also discussed.

Indoor environment and respiratory symptoms in children living in the Dutch-German borderland

OBJECTIVE

To investigate the relation between indoor environmental risk factors and respiratory symptoms in 7-8-year-old children living in the Dutch-German borderland.

METHODS

A nested case-control study was conducted among children participating in a large longitudinal study on respiratory health. Parents of all 781 children with respiratory complaints and an equal number of randomly selected controls were asked to complete a questionnaire, including questions on indoor environment.

RESULTS

The parents of 1191 children (76.2%) participated. Past exposure to environmental (OR = 2.73, 95% CI 1.14-6.67) as well as in utero exposure (OR = 2.28, 95% CI 1.15-4.53) to tobacco smoke, use of an unvented geyser for water heating (OR = 3.01, 95% CI 1.21-7.56), long-term exposure to dampness (OR = 2.98, 95% CI 1.10-8.28) or pets (OR = 2.18, 95% CI 1.39-3.42) increased the risk of asthmatic symptoms in 7-8-year-old children. A middle or low socio-economic status also increased the risk of asthmatic symptoms. An inverse association with asthmatic symptoms was seen for wall-to-wall carpeting (OR = 0.57, 95% CI 0.33-0.95) and insulation measures (OR = 0.46, 95% CI 0.25-0.83). Except for the presence of an unvented geyser, these environmental risk factors also presented a risk for coughing symptoms in children.

CONCLUSION

This study showed an increased risk of respiratory symptoms in children exposed to several indoor environmental risk factors.

The Role of Fungi in Chronic Rhinosinusitis

Collective clinical and bench observations of the past 25 years have expanded interest in the role that fungi may play in developing and perpetuating inflammatory disease of the respiratory tract. As with any new concept, controversy regarding such a process has emerged, but it has served to stimulate increased interest and further study. Review of the current literature appears to offer strong evidence to support both allergic and nonallergic forms of noninvasive fungal inflammation. It remains to be seen whether or these forms of inflammation are inter-related or independent of one another. As investigation focusing upon these new concepts continues, it should lead to better understanding of chronic inflammatory disease of the respiratory tracts.

Mould/dampness exposure at home is associated with respiratory disorders in Italian children and adolescents: the SIDRIA-2 Study

AIMS

To report on the relation between home mould and/or dampness exposure and respiratory disorders in a large sample of children and adolescents in Italy, accounting for age at time of exposure.

METHODS

20,016 children (mean age 7 years) and 13,266 adolescents (mean age 13 years) completed questionnaires on indoor exposures and respiratory symptoms/diseases. Statistical analyses were adjusted for sex, age, questionnaire's compiler, area of residence, season of interview, parental educational status, family history of asthma, rhinitis, eczema, chronic obstructive pulmonary disease, presence of gas water heaters, passive smoking, pets, and active smoking (only for adolescents). Population attributable risk % (PAR) was also computed.

RESULTS

Asthma was more strongly related to only early than to only current exposure, both in children (OR 1.80, 95% CI 1.41 to 2.30) and adolescents (OR 1.89, 95% CI 1.38 to 2.59). The same result was found for rhino-conjunctivitis (OR 1.46, 95% CI 1.17 to 1.82), in children, and for wheeze among adolescents (OR 1.56, 95% CI 1.15 to 2.11). In children, wheeze (OR 1.98, 95% CI 1.47 to 2.66) and eczema (OR 1.44, 95% CI 1.09 to 1.91) were more strongly related to mould/dampness when exposed both early and currently; the same occurred in adolescents for rhino-conjunctivitis (1.78, 95% CI 1.30 to 2.45). Although persistent cough/phlegm was significantly related to mould/dampness exposure in children, regardless of exposure timing, no significant association between mould/dampness exposure and eczema or cough/phlegm was found among adolescents. PAR estimates were higher for only early than only current exposures. Avoiding early only exposure would abate wheeze by 6%, asthma or cough/phlegm by 7%, rhino-conjunctivitis in children by 4%, and in adolescents, asthma by 6%, and wheeze by 4%.

CONCLUSIONS

Respiratory disorders such as wheeze and asthma can often be explained by exposure to home mould/dampness, especially early in life. The association seems more evident in children than in adolescents. These findings may suggest the need for environmental prevention strategies.

Building-related respiratory symptoms can be predicted with semi-quantitative indices of exposure to dampness and mold

Using a semi-quantitative mold exposure index, the National Institute for Occupational Safety and Health (NIOSH) investigated 13 college buildings to examine whether building-related respiratory symptoms among employees are associated with environmental exposure to mold and dampness in buildings. We collected data on upper and lower respiratory symptoms and their building-relatedness, and time spent in specific rooms with a self-administered questionnaires. Trained NIOSH industrial hygienists classified rooms for water stains, visible mold, mold odor, and moisture using semi-quantitative scales and then estimated individual exposure indices weighted by the time spent in specific rooms. The semi-quantitative exposure indices significantly predicted building-related respiratory symptoms, including wheeze [odds ratio (OR) = 2.3; 95% confidence interval (CI) = 1.1-4.5], chest tightness (OR = 2.2; 95% CI = 1.1-4.6), shortness of breath (OR = 2.7; 95% CI = 1.2-6.1), nasal (OR = 2.5; 95% CI = 1.3-4.7) and sinus (OR = 2.2; 95% CI = 1.2-4.1) symptoms, with exposure-response relationships. We found that conditions suggestive of indoor mold exposure at work were associated with building-related respiratory symptoms. Our findings suggest that observational semi-quantitative indices of exposure to dampness and mold can support action to prevent building-related respiratory diseases.

PRACTICAL IMPLICATIONS

Current air sampling methods have major limitations in assessing exposure to mold and other biological agents that may prevent the demonstration of associations of bioaerosol exposure with health. Our study demonstrates that semi-quantitative dampness/mold exposure indices, based solely on visual and olfactory observation and weighted by time spent in specific rooms, can predict existence of excessive building-related respiratory symptoms and diseases. Relative extent of water stains, visible mold, mold odor, or moisture can be used to prioritize remediation to reduce potential risk of building-related respiratory diseases. From a public health perspective, these observational findings justify action to correct water leaks and repair water damage in order to prevent building-related respiratory diseases. This approach can also be a basis for developing practical building-diagnostic tools for water-incursion.

Characterization of mold and moisture indicators in the home

As studies increasingly support the presence of health risks associated with mold and moisture, understanding fungal concentrations and physical measurements as they relate to the microenvironment becomes more important. We conducted a cross-sectional study in the homes of 64 subjects. The primary objective of this study was to use trained inspectors' list of indicators in rooms (bathroom, bedroom, and basement) and determine whether these indicators are associated with higher fungal levels or physical measurements. A new category for combining the concentrations of fungal species, referred to as moisture indicator fungi (MIF), is used in the analysis. Our results show that basements with a musty odor, efflorescence, water sources, or mold have a two- to threefold increase in fungal concentrations over basements without these indicators. The regression model for the basement was highly predictive of indoor MIF concentrations (r2 = .446, p = .017). Basement water sources are substantial predictors of indoor total fungi, MIF, and Aspergillus/Penicillium spp. MIF concentrations are higher in homes with basement water sources, and most notably, the increase in MIF concentrations is significant in other living spaces (bathroom and bedroom) of the dwelling. Basement water sources are important moisture/mold indicators for epidemiologists to use in exposure assessments performed in residential dwellings.

Indoor airborne fungal spores and home characteristics in asthmatic children from Edirne region of Turkey

BACKGROUND

The contribution of indoor fungal exposure to childhood asthma is not completely clear.

OBJECTIVE

To investigate airborne fungal flora within the homes of asthmatic and control children, and to assess the influence of housing characteristics regarding indoor fungi.

METHODS

Forty-seven atopic asthmatic and 23 nonatopic control children were studied. Allergen sensitivity was determined by skin prick tests. A thorough assessment, using a questionnaire and inspection surveys, was carried out. Home visits were made between October 2000 and February 2001. Samples of airborne fungal spores were collected from four rooms by the "open Petri dish" method. Indoor temperature and humidity were measured.

RESULTS

The total indoor fungal colony counts from the living rooms and bedrooms were significantly higher in the asthma group than in controls (p = .012 and p = .003, respectively). The most commonly isolated genus was Cladosporium. Twelve of the asthmatic patients (25.53 %) were found to be sensitive to fungal allergens. The factors found to be associated with indoor fungal growth in logistic regression were visible fungal patches in the bathrooms [(odds ratio (OR) = 5.75; 95 % CI 1.19 to 27.70)], and the age of the house [OR = 4.24; 95 % CI 1.34 to 13.45]. Total fungal colony numbers did not correlate with indoor temperature or humidity.

CONCLUSION

Fungal colony numbers were higher in the homes of asthmatic children than in those of controls. Therefore, indoor fungal exposure may contribute to childhood asthma. Bathrooms were the main source of fungal propagules. Old houses were more prone to fungal growth.

Estimating effects of moisture damage repairs on students' health-a long-term intervention study

Health symptom questionnaire responses were collected from upper secondary and high school students (n=245) before comprehensive repairs of moisture damage in the school. The questionnaire study was repeated 1 year (n=227), 3 years (n=256), and 5 years (n=233) after the repairs. The data were analyzed both in cross-sectional design including all respondents, and longitudinally including paired observations of those individuals who had responded both before and after the repairs. In addition, the effect of intervention on health symptoms was analyzed using generalized estimating equations (GEEs), taking into account within-subject correlation between repeated measurements. Compared to the situation before the repairs, the situation after the repairs was significantly improved in most of the 20 symptoms studied among the cross-sectional study populations. However, improvement was not so clear in the paired analysis and GEE analysis among the students who responded to three repeated questionnaires. The results indicate that the repairs succeeded in the sense that new cases of symptomatic students were no longer expected. However, the reversibility of symptoms among the group of exposed individuals may need to be considered separately.

Determination of aerial microbiological contamination in scholastic sports environments

AIMS

To assess the microbiological indoor air quality (IAQ) of high school and college gyms during physical training lessons and to evaluate the effective microbiological exposure of students.

METHODS AND RESULTS

Air samples from 11 high school and college gyms of Pavia, Italy were collected. Total bacterial counts, total fungal counts and characterization of fungal taxa were determined. Air quality was evaluated using three microbiological contamination indices: the global index of microbiological contamination per m3 (GIMC per m3), the index of mesophilic bacterial contamination (IMC) and the amplification index (AI).

CONCLUSIONS

This work testifies that air contamination in indoor gyms is always superior to that of the outdoor environment. Nevertheless, students are exposed to relatively low concentrations of airborne micro-organisms. The highest values of fungal counts and GIMC per m3 (>14,661) were observed between April and October when the central heating systems were switched off. The lowest fungal counts were detected in modern buildings equipped with forced ventilation systems. From qualitative aeromycological studies, 45 fungal taxa were identified, and different potentially allergenic species were isolated.

SIGNIFICANCE AND IMPACT OF THE STUDY

The standardization of air sampling methods and the correct evaluation of aeromicrobiological results allow the classification of indoor air healthiness. The proposed microbiological contamination indices together with the characterization of airborne fungal taxa are useful tools for detailed description of IAQ.

Indoor mold, toxigenic fungi, and Stachybotrys chartarum: infectious disease perspective

Damp buildings often have a moldy smell or obvious mold growth; some molds are human pathogens. This has caused concern regarding health effects of moldy indoor environments and has resulted in many studies of moisture- and mold-damaged buildings. Recently, there have been reports of severe illness as a result of indoor mold exposure, particularly due to Stachybotrys chartarum. While many authors describe a direct relationship between fungal contamination and illness, close examination of the literature reveals a confusing picture. Here, we review the evidence regarding indoor mold exposure and mycotoxicosis, with an emphasis on S. chartarum. We also examine possible end-organ effects, including pulmonary, immunologic, neurologic, and oncologic disorders. We discuss the Cleveland infant idiopathic pulmonary hemorrhage reports in detail, since they provided important impetus for concerns about Stachybotrys. Some valid concerns exist regarding the relationship between indoor mold exposure and human disease. Review of the literature reveals certain fungus-disease associations in humans, including ergotism (Claviceps species), alimentary toxic aleukia (Fusarium), and liver disease (Aspergillys). While many papers suggest a similar relationship between Stachybotrys and human disease, the studies nearly uniformly suffer from significant methodological flaws, making their findings inconclusive. As a result, we have not found well-substantiated supportive evidence of serious illness due to Stachybotrys exposure in the contemporary environment. To address issues of indoor mold-related illness, there is an urgent need for studies using objective markers of illness, relevant animal models, proper epidemiologic techniques, and examination of confounding factors.

Systemic immunoresponses in mice after repeated exposure of lungs to spores of Streptomyces californicus

Microbial growth in moisture-damaged buildings is associated with respiratory and other symptoms in the occupants. Streptomyces spp. are frequently isolated from such buildings. In the present study, we evaluated the responses of mice after repeated exposure to spores of Streptomyces californicus. Mice were exposed via intratracheal instillation to six doses (at 7-day intervals) of the spores of S. californicus, originally isolated from the indoor air of a moisture-damaged building, at three dose levels (2 x 10(3), 2 x 10(5), and 2 x 10(7) spores). Inflammation and toxicity, including changes in cell populations in the lungs, lymph nodes, and spleen, were evaluated 24 h after the last dosage. The exposure provoked a dose-dependent inflammatory cell response, as detected by the intense recruitment of neutrophils, but the numbers of macrophages and lymphocytes in the airways also increased. The cellular responses corresponded to the dose-dependent increases in inflammation- and cytotoxicity-associated biochemical markers (i.e., levels of albumin, total protein, and lactate dehydrogenase) in bronchoalveolar lavage fluid. The spore exposure increased the number of both activated and nonactivated T lymphocytes. Also, the amounts of CD3(-) CD4(-) and unconventional CD3(-) CD4(+) lymphocytes in the lung tissue were augmented. Interestingly, the spore exposure decreased cells in the spleen. This effect was strongest at the dose of 2 x 10(5) spores. These results indicate that the spores of S. californicus are capable of provoking both immunostimulation in lungs (inflammation) and systemic immunotoxicity, especially in the spleen. The immunotoxic effect resembled that caused by chemotherapeutic agents, originally isolated from Streptomyces spp. Thus, S. californicus must be considered a microbial species with potential to cause systemic adverse health effects in occupants of moisture-damaged buildings.

Immunoglobulin G antibodies of children exposed to microorganisms in a water-damaged school

The aim of this study was to determine whether exposure to fungi (molds and yeasts) among children attending a water-damaged school was reflected by the children's immunoglobulin G (IgG) response to microorganisms typical of water damage and whether the presence of these IgG antibodies was associated with respiratory symptoms and morbidity. The relationships between positive IgG antibodies and atopy, described as elevated allergen-specific immunoglobulin E (IgE) antibodies, were also examined. The study population consisted of a randomly selected group of exposed children attending a water-damaged school and a group of unexposed children of the same age. Serum samples for analyses of IgG and IgE antibodies were drawn from the children. The respiratory morbidity, the number of positive IgG antibodies to nine microorganisms indicating water damage, and IgE sensitization to common environmental allergens (Phadiatop) were studied. The mean number of positive IgG findings was significantly higher among the exposed children. The number of positive IgG antibodies did not correlate with respiratory illnesses or symptoms at the individual level even though the exposed children who had positive IgG antibodies to four or more microorganisms in the total group comparison tended to have higher respiratory morbidity. In the exposed group, a negative correlation was found between the number of positive IgG antibodies and the total value of allergen-specific IgE antibodies. As among adults exposed to microorganisms at work, IgG antibodies in children seem to be a relevant indicator of exposure to microorganisms in a water-damaged school on the group level.

Mycobacterium terrae isolated from indoor air of a moisture-damaged building induces sustained biphasic inflammatory response in mouse lungs

Occupants in moisture-damaged buildings suffer frequently from respiratory symptoms. This may be partly due to the presence of abnormal microbial growth or the altered microbial flora in the damaged buildings. However, the specific effects of the microbes on respiratory health and the way they provoke clinical manifestations are poorly understood. In the present study, we exposed mice via intratracheal instillation to a single dose of Mycobacterium terrae isolated from the indoor air of a moisture-damaged building (1 X 10(7), 5 X 10(7), or 1 X 10(8) microbes). Inflammation and toxicity in lungs were evaluated 2 hr later. The time course of the effects was assessed with the dose of 1 X 10(8) bacterial cells for up to 28 days. M. terrae caused a sustained biphasic inflammation in mouse lungs. The characteristic features for the first phase, which lasted from 6 hr to 3 days, were elevated proinflammatory cytokine [i.e., tumor necrosis factor alpha (TNF-alpha) and interleukin-6 (IL-6)] levels in the bronchoalveolar lavage fluid (BALF). TNF-alpha was produced in the lungs more intensively than was IL-6. Neutrophils were the most abundant cells in the airways during the first phase, although their numbers in BALF remained elevated up to 21 days. The characteristics of the second phase, which lasted from 7 to 28 days, were elevated TNF-alpha levels in BALF, expression of inducible nitric oxide synthase in BAL cells, and recruitment of mononuclear cells such as lymphocytes and macrophages into the airways. Moreover, total protein, albumin, and lactate dehydrogenase concentrations were elevated in both phases in BALF. The bacteria were detected in lungs up to 28 days. In summary, these observations indicate that M. terrae is capable of provoking a sustained, biphasic inflammation in mouse lungs and can cause a moderate degree of cytotoxicity. Thus, M. terrae can be considered a species with potential to adversely affect the health of the occupants of moisture-damaged buildings.

Inflammatory potential of the spores of Penicillium spinulosum isolated from indoor air of a moisture-damaged building in mouse lungs

Excess moisture and microbial growth have been associated with adverse health effects, especially in the airways, of the inhabitants of moisture-damaged buildings. The spores of Penicillium spp. are commonly present in the indoor air, both in moisture-damaged and in reference buildings, though their numbers seem to be significantly higher in the damaged buildings. To assess the potential of Penicillium spinulosum to evoke harmful respiratory effects, mice were exposed via intratracheal instillation to a single dose of the spores of P. spinulosum, isolated from the indoor air of a moisture-damaged building (1×10(5), 1×10(6), 5×10(6), 1×10(7) or 5×10(7) spores). Inflammation and toxicity in lungs were evaluated 24 h later. The time-course of the effects was investigated with the dose of 5×10(6) spores for 28 days. The fungal spores caused mild transient inflammation. The spore exposure transiently increased proinflammatory cytokine (TNFα and IL-6) levels in bronchoalveolar lavage fluid (BALF) in a dose- and time-dependent manner. The highest concentrations of both cytokines were measured at 6 h after a single dosage. The spore exposure did not cause expression of inducible nitric oxide synthase in lavaged cells. Neutrophils were acutely recruited into airways, but the response leveled off in 3 days. Neither cytotoxicity nor major changes in vascular permeability (i.e. increases in albumin, total protein, lactate dehydrogenase or hemoglobin levels in BALF) were observed in the lungs. Considering the profile and magnitude of the changes and the dose of the spores, we conclude that P. spinulosum has a low potential to cause acute respiratory inflammation, nor does it cause direct cytotoxicity.

Living with asthma: the experiences of young people at home and at school

This study is concerned with how young people with moderate to severe asthma live with and explain the disorder and manage the resulting symptoms. Based on in-depth interviews with 55 young people aged 11-16 living in West London, it shows that asthma restricted their lives at school and recreationally but that they were actively involved with their condition and its management. The study reveals that while prescribed medicines in the form of inhalers were used as the primary means of coping with asthma episodes, the young people were concerned about being dependent on such medicines, in line with more general ambivalence in late modern cultures about the long term use of prescribed medicines. It also demonstrates how social relations in particular contexts help to determine the extent to which asthma episodes can be managed.

Home and allergic characteristics of children with asthma in seven U.S. urban communities and design of an environmental intervention: the Inner-City Asthma Study

Most published environmental remediation interventions have been directed at single allergens and have employed demanding strategies; few have been performed in the homes of inner-city children disproportionately burdened by asthma. Our objective was a) to describe the allergen sensitivities, environmental tobacco smoke (ETS) exposure, and home environmental characteristics of a national sample of inner-city children with moderate to severe asthma and b) to develop and implement a multifaceted, home-based comprehensive intervention to reduce home allergens and ETS, tailored to the specific sensitization and exposure profiles of those children. Allergen skin testing and a home evaluation were performed to determine the presence of ETS and factors known to be associated with increased indoor allergen levels. Based on published remediation techniques, a home environmental intervention, organized into modules, each addressing one of five specific allergen groups or ETS, was designed. Of 994 allergic children from seven U.S. urban communities, 937 successfully completed baseline interviews and home allergen surveys and were enrolled. More than 50% of children had positive skin tests to three or more allergen groups. Cockroaches were reported in 58% of homes, wall-to-wall carpeting in the child's bedroom in 55%, a smoker in 48%, mice or rats in 40%, and furry pets in 28%. More than 60% of enrolled families received four or more modules, and between 94% and 98% of all modules were completed. We conclude that most inner-city children with moderate to severe asthma are sensitized to multiple indoor allergens and that environmental factors known to be associated with asthma severity are commonly present in their homes. The intervention developed for the Inner-City Asthma Study employs accepted methods to address an array of allergens and ETS exposure while ensuring that the intervention is tailored to the specific sensitization profiles and home characteristics of these children.

From local concern to randomized trial: the Watcombe Housing Project

BACKGROUND

A randomized study of the effect on people's health of improving their housing is underway in Torbay. The link between poor health, particularly respiratory health, and poor housing conditions has been recognized for a long time, but there have been few intervention studies to demonstrate that improving housing can improve health. In 1994, South and West Devon Health Authority set up a community development project in a deprived area of Torbay, in response to the concerns of local primary health-care workers. A community development worker helped local residents survey their homes for dampness and record their respiratory symptoms. The survey reported high levels of condensation/dampness and respiratory illness and the Council agreed to direct the majority of their housing improvement funds to the estate over the next 3 years. The Health Authority, University of Plymouth and Torbay Council were successful in obtaining funding to evaluate the housing improvements from the NHS R & D programme.

PARTICIPANTS AND METHODS

Of 119 houses eligible for the study, 50 were chosen at random and improved in the first year. The rest were improved the following year. Questionnaires screening for health problems were sent to all 580 residents and baseline surveys of the indoor environment were also carried out. More detailed health surveys were completed by community nurses visiting residents in their homes. All adults were asked to complete SF-36 and GHQ 12 questionnaires, as well as disease-specific questionnaires if appropriate.

PROGRESS

All houses in the study have now been improved, including insulation, double-glazing, re-roofing, heating, ventilation and electrical rewiring. Follow-up surveys are underway.

Health effects of indoor molds

Molds grow readily indoors in the presence of dampness. Their visibility enables their effects to be investigated by means of questionnaire surveys, although these are subject to imprecision and potential bias. Exposure to airborne mold particles can be measured in various ways that also have disadvantages and limitations. Many surveys have been conducted on the health effects of molds; most have examined the association between molds and symptoms, although some studies have used lung function tests and other objective health indices. Most surveys suggest that indoor mold growth is associated with ill health, particularly of the respiratory tract. Knowing how important mold exposure really is in health terms is difficult, owing to the tendency for mold growth to be associated with other factors that are prejudicial to health.

Inflammatory responses in mice after intratracheal instillation of spores of Streptomyces californicus isolated from indoor air of a moldy building

Microbial growth in buildings is associated with respiratory symptoms in the occupants. However, the specific effects of the microbes and the way they provoke clinical manifestations are poorly understood. In the current study, mice were exposed via intratracheal instillation to single doses of the spores of Streptomyces californicus, isolated from indoor air of a moisture-damaged building (2.2 x 10(7), 1.1 x 10(8), and 3.3 x 10(8) spores), or lipopolysaccharide (50 microg). Inflammation and toxicity in lungs were evaluated 24 h later. The time course of the effects was explored with the dose of 1.1 x 10(8) spores for up to 7 days. The microbial spores elevated proinflammatory cytokine (i.e., TNFalpha and IL-6) levels in bronchoalveolar lavage fluid (BALF) and in serum in a dose- and time-dependent manner and evoked expression of inducible nitric oxide synthase in BAL cells. Both TNFalpha and IL-6 responses peaked at 6 h after instillation, but TNFalpha leveled off more quickly than IL-6. The cytokine surge was followed by inflammatory cell recruitment into airways. Moreover, the spores increased dose- and time-dependently total protein, albumin, hemoglobin, and lactate dehydrogenase concentrations in BALF during the first 24 h. Histopathological examination of lungs confirmed the inflammatory changes. With the exception of macrophage and lymphocyte numbers, all parameters returned to control level at 7 days. In summary, these observations indicate that the spores of S. californicus are capable of provoking an acute inflammation in mouse lungs and can cause cytotoxicity. Thus, S. californicus can be considered as a species with potential to cause adverse health effects in occupants of moisture-damaged buildings.

Increased prevalence of atopy among children exposed to mold in a school building

BACKGROUND

The purpose of this study was to assess the occurrence of immunoglobulin E sensitization to common environmental allergens (atopy) and new allergic diseases among schoolchildren after starting school in a water-damaged school building. The staff and pupils of a Finnish elementary school with visible water damage and mold complained of respiratory and skin symptoms. The school building was examined and widespread moisture damage was found. A control school with no visible water damage was also examined. No indication of exceptional microbial growth was found in the samples taken from this school.

METHODS

History of allergic diseases and the year of diagnosis were established by a questionnaire. IgE antibodies to the common environmental allergens were determined from randomly selcted groups from both schools.

RESULTS

Elevated IgE values were significantly more common among the exposed children, as was the occurrence of new allergic diseases after the children started at the school.

CONCLUSIONS

The odds ratios for the IgE values of the study groups indicated a possible relationship between exposure to microorganisms and IgE sensitization. Exposure to spores, toxins, and other metabolites of molds may have complex results with unknown immunogenic effects that may act as a nonspecific trigger for allergic sensitization leading to the development of atopy.

Respiratory morbidity among children following renovation of a water-damaged school

The authors sought to determine whether exposure to molds, resulting from moisture damage in a school, was associated with increased respiratory symptoms and morbidity among schoolchildren and whether the renovation of this building resulted in a decrease in prevalence of respiratory symptoms and morbidity. The study was a follow-up (1-y interval) of children between the ages of 7 and 12 y from two elementary schools in a Finnish suburb. In addition to a questionnaire completed by the parents, the authors assessed the respiratory health of children by examining the health records of a local health center. In the cross-sectional study, the prevalence of symptoms and infections were higher in the exposed group, as were visits to a physician and use of antibiotics. The school was renovated, after which all prevalence decreased and no significant differences remained, except for visits to a physician (according to questionnaire responses). Therefore, moisture damage and exposure to molds increased the indoor air problems of schools and affected the respiratory health of children.

Housing and health: does installing heating in their homes improve the health of children with asthma?

The objective of this study was to evaluate the use of NHS money to improve health by improving housing conditions. A pilot study assessing health outcomes before and after improving housing conditions was conducted, studying 72 children with previously diagnosed asthma living in 59 damp houses in Cornwall. The intervention was the installation of central heating. This improved the energy efficiency of the housing. The children's health was a symptom-based outcome measure for asthma and time lost from school. Improvements comprised installation of gas central heating in 28/59 (47%) houses, electric storage heaters in 22/59 (37%), solid fuel central heating in 7/59 (12%) and oil-fired central heating in 2/59 (4%) houses. Energy efficiency improved by a mean of 2.1 on the National Home Energy Rating scale (95% CI 1.68-2.47, P<0.001) in the 37/59 (62%) houses for which two readings were available. Initially, 69/72 (92%) children's bedrooms were unheated and 44/72 (61%) were damp; following improvements, the proportions were 10/72 (14%) and 15/72 (21%) respectively. All respiratory symptoms were significantly reduced after intervention; the greatest reduction was seen in nocturnal cough from a median score of 3 (most nights) to 1 (on one or several nights) (P<0.001) in the previous month. School-age children lost significantly less time from school for asthma in the previous 3 months (9.3 days per 100 school days before intervention and 2.1 days afterwards, P<0.01) but not for other reasons (1.4 days per 100 school days before and 3.2 after, P>0.05). In conclusion, this study provides the first evaluation of health outcomes following housing improvements. Lack of a comparison group means that effects of age, season and biased reporting cannot be eliminated. More work is needed to substantiate these results.