Allergy to fungi has been linked to a wide range of illnesses, including rhinitis and asthma. Therefore, exposure to fungi in home environment is an important factor for fungal allergy. The present study was aimed to investigate types of airborne fungi inside and outside the homes of asthmatic children and control subjects (nonasthmatic children). The dominant fungi were evaluated for their quantitative distribution and seasonal variation. The air samples were collected from indoors and immediate outdoors of 77 selected homes of children suffering from bronchial asthma/allergic rhinitis using Andersen volumetric air sampler. The isolated fungal genera/species were identified using reference literature, and statistical analysis of the dominant fungi was performed to study the difference in fungal concentration between indoor and immediate outdoor sites as well as in between different seasons. A total of 4423 air samples were collected from two indoor and immediate outdoor sites in a 1-year survey of 77 homes. This resulted in the isolation of an average of 110,091 and 107,070 fungal colonies per metric cube of air from indoor and outdoor sites, respectively. A total of 68 different molds were identified. Different species of Aspergillus, Alternaria, Cladosporium, and Penicillium were found to be the most prevalent fungi in Delhi homes, which constituted 88.6% of the total colonies indoors. Highest concentration was registered in autumn and winter months. Total as well as dominant fungi displayed statistically significant differences among the four seasons (p < 0.001). The largest number of isolations were the species of Aspergillus (>40% to total colony-forming units in indoors as well as outdoors) followed by Cladosporium spp. Annual concentration of Aspergillus spp. was significantly higher (p < 0.05) inside the homes when compared with outdoors. Most of the fungi also occurred at a significantly higher (p < 0.001) rate inside the homes when compared with immediate outdoors. Asthmatic children in Delhi are exposed to a substantial concentration of mold inside their homes as well as immediate outdoor air. The considerable seasonal distributions of fungi provide valuable data for investigation of the role of fungal exposure as a risk for respiratory disorders among patients suffering from allergy or asthma in Delhi.
Asthma; Delhi; indoor fungi; prevalence; respiratory allergy; seasonal variation
Evidence that indoor dampness and mold growth are associated with respiratory health has been accumulating, but few studies have been able to examine health risks in relation to measured levels of indoor mold exposure. In particular, little is known about the contribution of indoor molds to the development of allergic sensitization. As a part of an ongoing study examining the effects of ambient air pollutants on respiratory health and atopic diseases in German school children, we examined the relation between viable mold levels indoors and allergic sensitization in 272 children. We examined whether allergic sensitization in children is associated with higher fungal spore count in settled house dust sampled from living room floors. Adjusting for age, sex, parental education, region of residency, and parental history of atopy, we found that mold spore counts for Cladosporium and Aspergillus were associated with an increased risk of allergic sensitization. Sensitized children exposed to high levels of mold spores (> 90th percentile) were more likely to suffer from symptoms of rhinoconjunctivitis. We conclude that elevated indoor concentrations of molds in wintertime might play a role in increasing the risk of developing atopic symptoms and allergic sensitization not only to molds but also to other common, inhaled allergens. These effects were strongest in the group of children who had lived in the same home since birth.
Qualitative reporting of home indoor moisture problems predicts respiratory diseases. However, causal agents underlying such qualitative markers remain unknown.
In the homes of 198 multiple allergic case children and 202 controls in Sweden, we cultivated culturable fungi by directly plating dust, and quantified(1–3, 1–6)-β-D-glucan, and ergosterol in dust samples from the child’s bedroom. We examined the relationship between these fungal agents and degree of parent or inspector reported home indoor dampness, and microbiological laboratory’s mold index. We also compared the concentrations of these agents between multiple allergic cases and healthy controls, as well as IgE-sensitization among cases.
The concentrations of culturable fungal agents were comparable between houses with parent and inspector reported mold issues and those without. There were no differences in concentrations of the individual or the total summed culturable fungi, (1–3, 1–6)-β-D-glucan, and ergosterol between the controls and the multiple allergic case children, or individual diagnosis of asthma, rhinitis or eczema.
Culturable fungi, (1–3, 1–6)-β-D-glucan, and ergosterol in dust were not associated with qualitative markers of indoor dampness or mold or indoor humidity. Furthermore, these agents in dust samples were not associated with any health outcomes in the children.
indoor; asthma; allergies; children; dampness; mold
Endotoxin, a component of the cell walls of gram-negative bacteria, is a contaminant in organic dusts (house dust) and aerosols. In humans, small amounts of endotoxin may cause a local inflammatory response. Exhaled nitric oxide (eNO) levels, an inflammation indicator, are associated with the pH values of exhaled breath condensate (EBC). This study evaluated seasonal changes on indoor endotoxin concentrations in homes and the relationships between endotoxin exposure and eNO/EBC pH levels for healthy children and children with allergy-related respiratory diseases. In total, 34 children with allergy-related respiratory diseases and 24 healthy children were enrolled. Indoor air quality measurements and dust sample analysis for endotoxin were conducted once each season inside 58 surveyed homes. The eNO, EBC pH levels, and pulmonary function of the children were also determined. The highest endotoxin concentrations were on kitchen floors of homes of children with allergy-related respiratory diseases and healthy children, and on bedroom floors of homes of asthmatic children and healthy children. Seasonal changes existed in endotoxin concentrations in dust samples from homes of children with allergic rhinitis, with or without asthma, and in EBC pH values among healthy children and those with allergy-related respiratory diseases. Strong relationships existed between endotoxin exposure and EBC pH values in children with allergic rhinitis.
With phenomenal growth of Bangalore city and a distinct shift of its arboriculture in the last 2 decades, change in allergen profile has been suspected. Earlier studies reported the pollen of Partheenium, Albizia, Cassia, Ageratum and Ricinus, and dust mites D.pteronyssinus and D.farinae to be the commonest airborne allergens (Anand P and Agashe SN, Ind Journal Otolaryngol, Vol 36, no 2, 1984 and Channabasavanna GP, Final Report: Research Project H Dust Mites, DST, Gov Ind June 1983).
Present study involved skin prick tests done on 134 patients of respiratory allergy with standard protocol. 82 male and 52 female patients with moderate–severe persistent allergic rhinitis, rhinoconjunctivitis and asthma were the study subjects with mean age of 30.2 ± 13.8 years. 30 were asthmatics and 64 were asthmatics with rhinitis.
Cynodon dactylon (22.4%) and Pennisetum typhoides (5.9%) are the commonest grass pollen allergens. Artemesia scoparia (15.7%), Partheenium hysterophorus (8.9%), Ageratum conyzoides (8.2%) and Helianthus annuus (8.2%) are the commonest weed pollen allergens. Prosopis juliflora (14.2%), Cassia siamea (10.4%) and Ricinus communis (8.9%) are the commonest tree pollen allergens. D.pteronyssinus (58.9%) and D.farinae (47%) are the commonest indoor allergens.
House dust mites have remained the predominant indoor allergens even now. Present study shows significant change in the type of pollen allergens. Cynodon, Artemesia and Prosopis have replaced Partheenium and Albizia as the predominant allergens in 2 decades. Helianthus annuus and Pennisetum typhoides, which were insignificant in the past, have emerged as significant allergens. Molds as airborne allergens have become very insignificant.
Bangalore has grown enormously in the last 2 decades. Innumerable vacant lands and swampy areas covered by weeds like Partheenium, have become buildings. Helianthus is cultivated on a large scale all around as a commercial crop. Large outskirts around the city have become residential and, office and commercial hubs resulting in a considerable change in pollen allergen flora. This change in the pollen allergen profile is an important guideline for allergy diagnosis and immunotherapy. This evidence may have significant application to the management of allergy patients in other major cities of India like Hyderabad, Chennai, Delhi, Mumbai and Kolkata as well.
of allergen necessary to sensitise genetically "at risk" children
is unclear. The relation between allergen exposure and asthma is also uncertain.
ensure a wide range of allergen exposures the data from case-control
studies of asthma in children aged 12-14 years attending three schools
in Los Alamos, New Mexico and Central Virginia were combined. Skin
prick tests to indoor and outdoor allergens and bronchial
hyperreactivity to histamine were assessed in children with and
without symptoms of asthma. The concentration of mite, cat, and
cockroach allergens in dust from the children's homes was used as a
marker of exposure.
hundred and thirty two children (157 with asthmatic symptoms and 175 controls) were investigated. One hundred and eighty three were
classified as atopic on the basis of allergen skin prick tests and 68 as asthmatic (symptoms plus bronchial responsiveness). The prevalence
and degree of sensitisation to mite and cockroach, but not cat, was
strongly associated in atopic children with increasing domestic
concentrations of these allergens. Asthma was strongly associated with
sensitisation to indoor allergens (p<10-6) and weakly to
outdoor allergens (p = 0.026). There was an association between current
asthma and the concentration of mite allergen amongst atopic children
(p = 0.008) but not amongst those who were specifically mite
sensitised (p = 0.16).
domestic reservoir concentration of mite and cockroach, but not cat,
allergen was closely related to the prevalence of sensitisation in
atopic children. However, the prevalence of current asthma had a
limited relationship to these allergen measurements, suggesting that
other factors play a major part in determining which allergic
individuals develop asthma.
Exhaled nitric oxide (eNO) is increasingly used as a non-invasive measure of airway inflammation. Despite this, little information exists regarding the potential effects of indoor microbial components on eNO. We determined the influence of microbial contaminants in house dust and other indoor environmental characteristics on eNO levels in seven-year-olds with and without a physician- diagnosis of asthma. The study included 158 children recruited from a birth cohort study, and 32 were physician-diagnosed as asthmatic. The relationship between eNO levels and exposures to home dust streptomycetes, endotoxin, and molds was investigated. Streptomycetes and endotoxin were analyzed both as loads and concentrations in separate models. Dog, cat, and dust mite allergens also were evaluated. In the multivariate exposure models high streptomycetes loads and concentrations were significantly associated with a decrease in eNO levels in asthmatic (p <0.001) but not in healthy children. The presence of dog allergen, however, was associated with increased levels of eNO (p = 0.001). Dust endotoxin was not significant. The relationship between eNO and indoor exposure to common outdoor molds was u-shaped. In non-asthmatic children, none of the exposure variables were significantly associated with eNO levels. To our knowledge, this is the first study demonstrating a significant association between microbial components in the indoor environment and eNO levels in asthmatic children. This study demonstrates the importance of simultaneously assessing multiple home exposures of asthmatic children to better understand opposing effects. Common components of the indoor Streptomyces community may beneficially influence airway inflammation.
streptomycetes; mold; allergens; asthma; exhaled nitric oxide; children
Studies have repeatedly demonstrated that sensitization to fungi, such as Alternaria, is strongly associated with allergic rhinitis and asthma in children. However, the role of exposure to fungi in the development of childhood allergic rhinitis is poorly understood. In a prospective birth cohort of 405 children of asthmatic/allergic parents from metropolitan Boston, Massachusetts, we examined in-home high fungal concentrations (> 90th percentile) measured once within the first 3 months of life as predictors of doctor-diagnosed allergic rhinitis in the first 5 years of life. In multivariate Cox regression analyses, predictors of allergic rhinitis included high levels of dust-borne Aspergillus [hazard ratio (HR) = 3.27; 95% confidence interval (CI), 1.50–7.14], Aureobasidium (HR = 3.04; 95% CI, 1.33–6.93), and yeasts (HR = 2.67; 95% CI, 1.26–5.66). The factors controlled for in these analyses included water damage or mild or mildew in the building during the first year of the child’s life, any lower respiratory tract infection in the first year, male sex, African-American race, fall date of birth, and maternal IgE to Alternaria > 0.35 U/mL. Dust-borne Alternaria and non-sporulating and total fungi were also predictors of allergic rhinitis in models excluding other fungi but adjusting for all of the potential confounders listed above. High measured fungal concentrations and reports of water damage, mold, or mildew in homes may predispose children with a family history of asthma or allergy to the development of allergic rhinitis.
allergic rhinitis; fungi; mold; respiratory health effects; water damage
Exposure to particulate matter (PM) air pollution has been shown to exacerbate children's asthma, but the exposure sources and temporal characteristics are still under study. Children's exposure to PM is likely to involve both combustion-related ambient PM and PM related to a child's activity in various indoor and outdoor microenvironments. Among 19 children with asthma, 9-17 years of age, we examined the relationship of temporal changes in percent predicted forced expiratory volume in 1 sec (FEV1) to personal continuous PM exposure and to 24-hr average gravimetric PM mass measured at home and central sites. Subjects were followed for 2 weeks during either the fall of 1999 or the spring of 2000, in a southern California region affected by transported air pollution. FEV(subscript)1(/subscript) was measured by subjects in the morning, afternoon, and evening. Exposure measurements included continuous PM using a passive nephelometer carried by subjects; indoor, outdoor home, and central-site 24-hr gravimetric PM2.5 (PM of aerodynamic diameter < 2.5 microm) and PM10; and central-site hourly PM10, nitrogen dioxide, and ozone. Data were analyzed with linear mixed models controlling for within-subject autocorrelation, FEV1 maneuver time, and exposure period. We found inverse associations of FEV1 with increasing PM exposure during the 24 hr before the FEV1 maneuver and with increasing multiday PM averages. Deficits in percent predicted FEV1 (95% confidence interval) for given PM interquartile ranges measured during the preceding 24-hr were as follows: 128 microg/m3 1-hr maximum personal PM, -6.0% (-10.5 to -1.4); 30 microg/m3 24-hr average personal PM, -5.9% (-10.8 to -1.0); 6.7 microg/m3 indoor home PM2.5, -1.6% (-2.8 to -0.4); 16 microg/m3 indoor home PM10, -2.1% (-3.7 to -0.4); 7.1 microg/m3 outdoor home PM2.5, -1.1% (-2.4 to 0.1); and 7.5 microg/m3 central-site PM2.5, -0.7% (-1.9 to 0.4). Stronger associations were found for multiday moving averages of PM for both personal and stationary-site PM. Stronger associations with personal PM were found in boys allergic to indoor allergens. FEV1 was weakly associated with NO2 but not with O3. Results suggest mixed respiratory effects of PM in asthmatic children from both ambient background exposures and personal exposures in various microenvironments.
Although outdoor particulate matter (PM) has been linked to mortality and asthma morbidity, the impact of indoor PM on asthma has not been well established.
This study was designed to investigate the effect of in-home PM on asthma morbidity.
For a cohort of 150 asthmatic children (2–6 years of age) from Baltimore, Maryland, a technician deployed environmental monitoring equipment in the children’s bedrooms for 3-day intervals at baseline and at 3 and 6 months. Caregivers completed questionnaires and daily diaries during air sampling. Longitudinal data analyses included regression models with generalized estimating equations.
Children were primarily African Americans (91%) from lower socioeconomic backgrounds and spent most of their time in the home. Mean (± SD) indoor PM2.5–10 (PM with aerodynamic diameter 2.5–10 μm) and PM2.5 (aerodynamic diameter < 2.5 μm) concentrations were 17.4 ± 21.0 and 40.3 ± 35.4 μg/m3. In adjusted models, 10-μg/m3 increases in indoor PM2.5–10 and PM2.5 were associated with increased incidences of asthma symptoms: 6% [95% confidence interval (CI), 1 to 12%] and 3% (95% CI, –1 to 7%), respectively; symptoms causing children to slow down: 8% (95% CI, 2 to 14%) and 4% (95% CI, 0 to 9%), respectively; nocturnal symptoms: 8% (95% CI, 1 to 14%) and 6% (95% CI, 1 to 10%), respectively; wheezing that limited speech: 11% (95% CI, 3 to 19%) and 7% (95% CI, 0 to 14%), respectively; and use of rescue medication: 6% (95% CI, 1 to 10%) and 4% (95% CI, 1 to 8%), respectively. Increases of 10 μg/m3 in indoor and ambient PM2.5 were associated with 7% (95% CI, 2 to 11%) and 26% (95% CI, 1 to 52%) increases in exercise-related symptoms, respectively.
Among preschool asthmatic children in Baltimore, increases in in-home PM2.5–10 and PM2.5 were associated with respiratory symptoms and rescue medication use. Increases in in-home and ambient PM2.5 were associated with exercise-related symptoms. Although reducing PM outdoors may decrease asthma morbidity, reducing PM indoors, especially in homes of inner-city children, may lead to improved asthma health.
air pollution; asthma; indoor; particulate matter; pediatric; urban
Evidence for environmental causes of asthma is limited, especially among African Americans. To look for systematic differences in early life domestic exposures between inner-city preschool children with and without asthma, we performed a study of home indoor air pollutants and allergens.
Children 2–6 years of age were enrolled in a cohort study in East Baltimore, Maryland. From the child’s bedroom, air was monitored for 3 days for particulate matter ≤ 2.5 and ≤ 10 μm in aerodynamic diameter (PM2.5, PM10), nitrogen dioxide, and ozone. Median baseline values were compared for children with (n = 150) and without (n = 150) asthma. Housing characteristics related to indoor air pollution were assessed by caregiver report and home inspection. In addition, indoor allergen levels were measured in settled dust.
Children were 58% male, 91% African American, and 88% with public health insurance. Housing characteristics related to pollutant exposure and bedroom air pollutant concentrations did not differ significantly between asthmatic and control subjects [median: PM2.5, 28.7 vs. 28.5 μg/m3; PM10, 43.6 vs. 41.4 μg/m3; NO2, 21.6 vs. 20.9 ppb; O3, 1.4 vs. 1.8 ppb; all p > 0.05]. Settled dust allergen levels (cat, dust mite, cockroach, dog, and mouse) were also similar in bedrooms of asthmatic and control children.
Exposures to common home indoor pollutants and allergens are similar for inner-city preschool children with and without asthma. Although these exposures may exacerbate existing asthma, this study does not support a causative role of these factors for risk of developing childhood asthma.
African American; air pollution; allergens; asthma; particulate matter; pediatric; urban
India is an ethnically diverse country with an approximate population of 1.2 billion. The frequency of beta-thalassemia trait (βTT) has variously been reported from <1% to 17% and an average of 3.3%. Most of these studies have been carried out on small population groups and some have been based on hospital-based patients. There is also a variation in the prevalence of hemoglobinopathies in different regions and population groups in the country. A high frequency of Hb D has been reported from the North in the Punjabi population, Hb E in the eastern region of India and Hb S is mainly reported from populations of tribal origin from different parts of the country.
To study the gene frequency of βTT and other hemoglobinopathies in three regions East (Kolkata), West (Mumbai) and North (Delhi) in larghe population group (schoolchildren) for a more accurate assessment of gene frequency for planning of control programmes for haemoglobinopathies.
MATERIALS AND METHODS:
This study included 5408 children from 11 schools in Delhi, 5682 from 75 schools in Mumbai and 957 schoolchildren from Kolkata who were screened for βTT and haemoglobinopathies. These included 5684 children from 75 schools in Mumbai and 5408 children from 11 schools in Delhi. Children were 11-18 years of age of both sexes. The final report is, however, only on 11090 schoolchildren from Mumbai and Delhi as data from Kolkata was restricted both in numbers and objectives and could not be included for comparison.
The overall gene frequency of βTT in Mumbai and Delhi was 4.05% being 2.68% and 5.47% in children of the two cities respectively. In Mumbai, the gene frequency was evenly distributed. Majority of the children with βTT from Mumbai were from Marathi (38.9%) and Gujarati (25%) speaking groups. Gene frequency was >5% in Bhatias, Khatris, Lohanas and Schedule Castes. In Delhi, a higher incidence was observed in schoolchildren of North and West Delhi (5.8-9.2%). The schoolchildren of North and West Delhi comprised predominantly of Punjabi origin compared to children in the South of the city (2.2%, 2.3%). When analyzed state-wise, the highest incidence was observed in children of Punjabi origin (7.6%) and was >4% from several other states. Majority of the traits from Mumbai were anemic (95.1% male and 85.6% in female). The prevalence of anemia was lower (62.7% male and 58.4% female) children with βTT from Delhi. This was a reflection of the higher prevalence of anemia in children without hemoglobinopathy in Mumbai than in Delhi. Nutritional deficiency was probably more severe and rampant in children Mumbai. Gene frequency of Hb D was greater in schoolchildren from Delhi (1.1%) than in Mumbai (0.7%). Hb S trait (0.2%) was observed exclusively in children from Mumbai. A low incidence of Hb E trait (0.04%) was seen in children in Mumbai. A higher incidence is reported from the East. The number of cases studied from the eastern region was small as the data from the East (Kolkata) could not be included in the analysis.
This study comprises a larger number of children studied for the gene frequency of βTT and other hemoglobinopathies from India. Population groups with higher gene frequencies require screening programmes and facilities for antenatal diagnosis as well as increased awareness and educational programmes to control the birth of thalassemic homozygotes. The overall carrier frequency of βTT was 4.05% and reinforces the differential frequency of β-thalassemia trait in schoolchildren from Delhi and Mumbai and the higher incidence of hemoglobin D in Punjabis as reported previously. The birth incidence calculated thereof for homozygous thalassemics would be 11,316 per year which are added each year to the existing load of homozygous thalassemics. This is much higher than the previously reported number of births annually. Hence suitable control measures need to be undertaken urgently in India.
β-thalassemia trait; Hemoglobinopathies; India
There are few studies on associations between children’s respiratory heath and air pollution in schools in China. The industrial development and increased traffic may affect the indoor exposure to air pollutants in school environment. Moreover, there is a need to study respiratory effects of environmental tobacco smoke (ETS) and emissions from new building materials in homes in China.
We studied the associations between pupils’ asthmatic symptoms and indoor and outdoor air pollution in schools, as well as selected home exposures, in a coal-burning city in north China.
A questionnaire survey was administered to pupils (11–15 years of age) in 10 schools in urban Taiyuan, collecting data on respiratory health and selected home environmental factors. Indoor and outdoor school air pollutants and climate factors were measured in winter.
A total of 1,993 pupils (90.2%) participated; 1.8% had cumulative asthma, 8.4% wheezing, 29.8% had daytime attacks of breathlessness. The indoor average concentrations of sulfur dioxide, nitrogen dioxide, ozone, and formaldehyde by class were 264.8, 39.4, 10.1, and 2.3 μg/m3, respectively. Outdoor levels were two to three times higher. Controlling for possible confounders, either wheeze or daytime or nocturnal attacks of breathlessness were positively associated with SO2, NO2, or formaldehyde. In addition, ETS and new furniture at home were risk factors for wheeze, daytime breathlessness, and respiratory infections.
Indoor chemical air pollutants of mainly outdoor origin could be risk factors for pupils’ respiratory symptoms at school, and home exposure to ETS and chemical emissions from new furniture could affect pupils’ respiratory health.
air pollution; asthma; China; formaldehyde; indoor; nitrogen dioxide; ozone; outdoor; school; sulfur dioxide
Compared to traditional methods of fungal exposure assessment, molecular methods have provided new insight into the richness of fungal communities present in both indoor and outdoor environments. In this study, we describe the diversity of fungi in the homes of asthmatic children located in Kansas City. Fungal diversity was determined by sequencing the internal transcribed spacer (ITS) regions of ribosomal RNA derived from fungi collected in air and dust samples from 31 homes participating in the Kansas City Safe and Healthy Homes Program (KCSHHP). Sequencing results were then compared to data obtained using viable and non-viable fungal exposure assessment methods. ITS clone libraries were predominantly derived from the phylum Ascomycota in both air (68%) and dust (92%) samples and followed by the Basidiomycota and Zygomycota. The majority of Ascomycota clones belonged to four orders including the Pleosporales, Eurotiales, Capnodiales, and Dothideales. ITS sequencing revealed the presence of a number of rarely documented fungal species placed in the Pleosporales. Several species placed in the Basidiomycota were detected in ITS clone libraries but not by viable or non-viable methods. The prevalence of organizational taxonomic units (OTUs) was significantly higher in air than in dust samples (p < 0.0001); however, no differences between OTUs in air samples collected in the subjects’ room and basement were observed. These sequencing results demonstrate a much broader diversity of Ascomycota and Basidiomycota communities in KCSHHP indoor environments than previously estimated using traditional methods of assessment.
The relationship between day-to-day changes in asthma severity and combined exposures to community air pollutants and aeroallergens remains to be clearly defined. We examined the effects of outdoor air pollutants, fungi, and pollen on asthma. Twenty-two asthmatics ages 9-46 years were followed for 8 weeks (9 May-3 July 1994) in a semirural Southern California community around the air inversion base elevation (1,200 ft). Daily diary responses included asthma symptom severity (6 levels), morning and evening peak expiratory flow rates (PEFR), and as-needed beta-agonist inhaler use. Exposures included 24-hr outdoor concentrations of fungi, pollen, and particulate matter with a diameter < 10 microns (PM10; maximum = 51 micrograms/m3) and 12-hour day-time personal ozone (O3) measurements (90th percentile = 38 ppb). Random effects longitudinal regression models controlled for autocorrelation and weather. Higher temperatures were strongly protective, probably due to air conditioning use and diminished indoor allergens during hot, dry periods. Controlling for weather, total fungal spore concentrations were associated with all outcomes: per minimum to 90th percentile increase of nearly 4,000 spores/m3, asthma symptom scores increased 0.36 (95% CI, 0.16-0.56), inhaler use increased 0.33 puffs (95% CI, -0.02-0.69), and evening PEFR decreased 12.1 l/min (95% CI, -1.8-22.3). These associations were greatly enhanced by examining certain fungal types (e.g., Alternaria, basidiospores, and hyphal fragments) and stratifying on 16 asthmatics allergic to tested deuteromycete fungi. There were no significant associations to low levels of pollen or O3, but inhaler use was associated with PM10 (0.15 inhaler puffs/10 micrograms/m3; p < 0.02). These findings suggest that exposure to fungal spores can adversely effect the daily respiratory status of some asthmatics.
Adverse respiratory effects in children with asthma are associated with exposures to nitrogen dioxide (NO2). Levels indoors can be much higher than outdoors. Primary indoor sources of NO2 are gas stoves, which are used for cooking by one-third of US households. We investigated effects of indoor NO2 exposure on asthma severity among an ethnically and economically diverse sample of children, controlling for season and indoor allergen exposure.
Children aged 5–10 years with active asthma (n=1,342), were recruited through schools in urban and suburban Connecticut and Massachusetts (2006–2009) for a prospective, year-long study with seasonal measurements of NO2 and asthma severity. Exposure to NO2 was measured passively for four, month-long, periods with Palmes tubes. Asthma morbidity was concurrently measured by a severity score and frequency of wheeze, night symptoms and use of rescue medication. We used adjusted, hierarchical ordered logistic regression models to examine associations between household NO2 exposure and health outcomes.
Every 5 ppb increase in NO2 exposure above a threshold of 6 ppb was associated with a dose-dependent increase in risk of higher asthma severity score (odds ratio= 1.37 [95% confidence interval= 1.01 – 1.89]), wheeze (1.49 [1.09 – 2.03]), night symptoms (1.52 [1.16 – 2.00]) and rescue medication use (1.78 [1.33 – 2.38]).
Asthmatic children exposed to NO2 indoors, at levels well below the US Environmental Protection Agency outdoor standard (53 ppb), are at risk for increased asthma morbidity. Risks are not confined to inner-city children, but occur at NO2 concentrations common in urban and suburban homes.
In this study, the culturability of indoor and outdoor airborne fungi was determined through long-term sampling (24-h) using a Button Personal Inhalable Aerosol Sampler. The air samples were collected during three seasons in six Cincinnati area homes that were free from moisture damage or visible mold. Cultivation and total microscopic enumeration methods were employed for the sample analysis. The geometric means of indoor and outdoor culturable fungal concentrations were 88 and 102 colony-forming units (CFU) m-3, respectively, with a geometric mean of the I/O ratio equal to 0.66. Overall, 26 genera of culturable fungi were recovered from the indoor and outdoor samples. For total fungal spores, the indoor and outdoor geometric means were 211 and 605 spores m-3, respectively, with a geometric mean of I/O ratio equal to 0.32. The identification revealed 37 fungal genera from indoor and outdoor samples based on the total spore analysis. Indoor and outdoor concentrations of culturable and total fungal spores showed significant correlations (r = 0.655, p<0.0001 and r = 0.633, p<0.0001, respectively). The indoor and outdoor median viabilities of fungi were 55% and 25%, respectively, which indicates that indoor environment provides more favorable survival conditions for the aerosolized fungi. Among the seasons, the highest indoor and outdoor culturability of fungi was observed in the fall. Cladosporium had a highest median value of culturability (38% and 33% for indoor and outdoor, respectively) followed by Aspergillus/Penicillium (9% and 2%) among predominant genera of fungi. Increased culturability of fungi inside the homes may have important implications because of the potential increase in the release of allergens from viable spores and pathogenicity of viable fungi on immunocompromised individuals.
Indoor air; Outdoor air; Total fungal spore; Culturable fungi; Culturability
In the United States, childhood asthma morbidity and prevalence rates are the highest in less affluent urban minority communities. More than 80% of childhood asthmatics are allergic to one or more inhalant allergens. We evaluated whether socioeconomic status was associated with a differential in the levels and types of indoor home allergens. Dust samples for an ELISA allergen assay were collected from the homes of 499 families as part of a metropolitan Boston, Massachusetts, longitudinal birth cohort study of home allergens and asthma in children with a parental history of asthma or allergy. The proportion of homes with maximum home allergen levels in the highest category was 42% for dust mite allergen (> or = 10 microg/g Der p 1 or Der f 1), 13% for cockroach allergen (> or = 2 U/g Bla g 1 or Bla g 2), 26% for cat allergen (> or = 8 microg/g Fel d 1), and 20% for dog allergen (> or = 10 microg/g Can f 1). Homes in the high-poverty area (> 20% of the population below the poverty level) were more likely to have high cockroach allergen levels than homes in the low-poverty area [51 vs. 3%; OR, 33; 95% confidence interval (CI), 12-90], but less likely to have high levels of dust mite allergen (16 vs. 53%; OR, 0.2; CI, 0.1-0.4). Lower family income, less maternal education, and race/ethnicity (black or Hispanic vs. white) were also associated with a lower risk of high dust mite levels and a greater risk of high cockroach allergen levels. Within a single U.S. metropolitan area we found marked between-community differences in the types of allergens present in the home, but not necessarily in the overall burden of allergen exposure.
This field study investigated the relationship between indoor and outdoor concentrations of airborne actinomycetes, fungal spores, and pollen. Air samples were collected for 24 h with a button inhalable aerosol sampler inside and outside of six single-family homes located in the Cincinnati area (overall, 15 pairs of samples were taken in each home). The measurements were conducted during three seasons – spring and fall 2004, and winter 2005. The concentration of culturable actinomycetes was mostly below the detection limit. The median indoor/outdoor ratio (I/O) for actinomycetes was the highest: 2.857. The indoor of fungal and pollen concentrations followed the outdoor concentrations while indoor levels were mostly lower than the outdoor ones. The I/O ratio of total fungal spores (median = 0.345) in six homes was greater than that of pollen grains (median = 0.025). The low I/O ratios obtained for pollen during the peak ambient pollination season (spring) suggest that only a small fraction penetrated from outdoor to indoor environment. This is attributed to the larger size of pollen grains. Higher indoor concentration levels and variability in the I/O ratio observed for airborne fungi may be associated with indoor sources and/or higher outdoor-to-indoor penetration of fungal spores compared to pollen grains.
Bioaerosol; Exposure; Indoor; Outdoor; Bacteria; Fungal spore; Pollen
Particulate matter (PM) exposures have been linked with poor respiratory health outcomes, especially among susceptible populations such as asthmatic children. Smoke from biomass combustion for residential home heating is an important source of PM in many rural or peri-urban areas in the United States.
To assess the efficacy of residential interventions that reduce indoor PM exposure from wood stoves and to quantify the corresponding improvements in quality of life and health outcomes for asthmatic children.
The Asthma Randomized Trial of Indoor wood Smoke (ARTIS) study is an in-home intervention study of susceptible children exposed to biomass combustion smoke. Children, ages 7 to 17, with persistent asthma and living in homes that heat with wood stoves were recruited for this three arm randomized placebo-controlled trial. Two household-level intervention strategies, wood stove replacement and air filters, were compared to a sham air filter placebo. Improvement in quality of life of asthmatic children was the primary outcomes. Secondary asthma-related health outcomes included peak expiratory flow (PEF) and forced expiratory volume in first second (FEV1), biomarkers in exhaled breath condensate, and frequency of asthma symptoms, medication usage, and healthcare utilization. Exposure outcomes included indoor and outdoor PM2.5 mass, particle counts of several size fractions, and carbon monoxide.
To our knowledge, this was the first randomized trial in the US to utilize interventions targeting residential wood stoves to assess the impact on indoor PM and health outcomes in a susceptible population.
pediatric; asthma; home intervention; wood stove; filter; biomass combustion
Active fungal proteinases are powerful allergens that induce experimental allergic lung disease strongly resembling atopic asthma, but the precise relationship between proteinases and asthma remains unknown. Here, we analyzed dust collected from the homes of asthmatic children for the presence and sources of active proteinases to further explore the relationship between active proteinases, atopy, and asthma. Active proteinases were present in all houses and many were derived from fungi, especially Aspergillus niger. Proteinase-active dust extracts were alone insufficient to initiate asthma-like disease in mice, but conidia of A. niger readily established a contained airway mucosal infection, allergic lung disease, and atopy to an innocuous bystander antigen. Proteinase produced by A. niger enhanced fungal clearance from lung and was required for robust allergic disease. Interleukin 13 (IL-13) and IL-5 were required for optimal clearance of lung fungal infection and eosinophils showed potent anti-fungal activity in vitro. Thus, asthma and atopy may both represent a protective response against contained airway infection due to ubiquitous proteinase-producing fungi.
Recent studies have identified associations between the concentration of phthalates in indoor dust and allergic symptoms in the airways, nose, and skin.
Our goal was to investigate the associations between allergic symptoms in children and the concentration of phthalate esters in settled dust collected from children’s homes in Sofia and Burgas, Bulgaria.
Dust samples from the child’s bedroom were collected. A total of 102 children (2–7 years of age) had symptoms of wheezing, rhinitis, and/or eczema in preceding 12 months (cases), and 82 were nonsymptomatic (controls). The dust samples were analyzed for their content of dimethyl phthalate (DMP), diethyl phthalate (DEP), di-n-butyl phthalate (DnBP), butyl benzyl phthalate (BBzP), di(2-ethylhexyl) phthalate (DEHP), and di-n-octyl phthalate (DnOP).
A higher concentration of DEHP was found in homes of case children than in those of controls (1.24 vs. 0.86 mg/g dust). The concentration of DEHP was significantly associated with wheezing in the preceding 12 months (p = 0.035) as reported by parents. We found a dose–response relationship between DEHP concentration and case status and between DEHP concentration and wheezing in the preceding 12 months.
This study shows an association between concentration of DEHP in indoor dust and wheezing among preschool children in Bulgaria.
allergy; asthma; children; DEHP; phthalates
Studies of inner-city asthmatic children have shown significant regional variation in dust allergen exposures. The home environment of asthmatic children in the Gulf South region of the USA has not been characterized. This study describes indoor dust allergen levels in the homes of 86 asthmatic children in New Orleans and explores regional variability in dust allergen exposure. Data were used from baseline home visits of children in the New Orleans Healthy Homes Initiative. Interview, visual observation, and environmental dust sampling data of 86 children between 4 and 17 years of age were analyzed. Seventy-seven percent of households had moderate (>2.0–9.9 μg/g) or high (≥10.0 μg/g) levels of either Der p 1 or Der f 1 dust mite allergen and 56.6% had moderate (>2.0–8.0 U/g) or high (>8.0 U/g) levels of cockroach allergen (Bla g 1). The prevalence of high (>10 μg/g) levels of dog (Can f 1) allergen was 26.5%, and few households (6.0%) had high cat allergen (Fel d 1) levels (>8.0 μg/g). Households with average humidity levels >50% were three times more likely to have elevated dust mite levels (odds ratio=3.2; 95% confidence interval=1.1, 9.3; p=0.03). Home ownership and education level were inversely associated with cockroach and dust mite allergen levels, respectively. Our findings reinforce the evidence of regional variability in dust allergen exposure levels. Asthmatic children living in the Gulf South are exposed to multiple indoor allergen exposures and live in a highly allergenic environment.
Child health; Asthma; Allergens; Environmental health; Dog allergen; House dust
Exposure to airborne fungi has been associated with increased airway hyperreactivity and asthma prevalence.
To investigate the association between common indoor fungi and airway hyperreactivity measured by peak expiratory flow variability in asthmatic children.
Children 6 to 12 years of age (n = 225) with a physician diagnosis of asthma were enrolled in the study to have their peak expiratory flow recorded twice daily during a 2-week period. Genus-specific, quantitative, in-home airborne mold concentrations were measured. Logistic regression models were used to examine the relationship between a mean peak expiratory flow variability greater than 18.5% (75th percentile) and any mold in the home (total mold, Cladosporium, Penicillium, Aspergillus, and Alternaria).
Mold was detected in 93% of the homes. The most common molds were Cladosporium in 72% and Penicillium in 42% of the samples. Controlling for sex, ethnicity, age, and winter season of sampling, Penicillium measured in the home was associated with a mean peak expiratory flow variability greater than 18.5% (odds ratio, 2.4; 95% confidence interval, 1.2–4.8). Greater peak expiratory flow variability was not associated with total mold or other mold measured in the home.
Exposure to airborne Penicillium is associated with increased peak expiratory flow variability in asthmatic children.
Inner-city children have high rates of asthma. Exposures to particles, including allergens, may cause or exacerbate asthma symptoms. As part of an epidemiologic study of inner-city children with asthma, continuous (10-min average) measurements of particle concentrations were made for 2-week periods in 294 homes drawn from seven cities. Measurements were made using an optical scattering device that is most sensitive to fine particles. The concentrations recorded by these devices were corrected to agree with colocated outdoor gravimetric PM2.5 monitors. Indoor concentrations in the homes averaged 27.7 (standard deviation = 35.9) micro g/m3, compared with concurrent outdoor concentrations of 13.6 (7.5) micro g/m3. A multivariate model indicated that outdoor particles penetrated indoors with an efficiency of 0.48 and were therefore responsible for only 25% of the mean indoor concentration. The major indoor source was smoking, which elevated indoor concentrations by 37 micro g/m3 in the 101 homes with smokers. Other significant sources included frying, smoky cooking events, use of incense, and apartment housing, although the increases due to these events ranged only from 3 to 6 micro g/m3. The 10-min averaging time allowed calculation of an average diurnal variation, showing large increases in the evening due to smoking and smaller increases at meal times due to cooking. Most of the observed variance in indoor concentrations was day to day, with roughly similar contributions to the variance from visit to visit and home to home within a city and only a small contribution made by variance among cities. The small variation among cities and the similarity across cities of the observed indoor air particle distributions suggest that sources of indoor concentrations do not vary considerably from one city to the next, and thus that simple models can predict indoor air concentrations in cities having only outdoor measurements.