Homes Of Asthmatic Children Research Articles

Quantitative PCR analysis of molds in the dust from homes of asthmatic children in North Carolina

The vacuum bag (VB) dust from the homes of 19 asthmatic children in North Carolina (NC) was analyzed by mold specific quantitative PCR. These results were compared to the analysis of the VB dust from 176 homes in the HUD, American Healthy Home Survey of homes in the US. The Environmental Relative Moldiness Index (ERMI) was calculated for each of the homes. The mean and standard deviation (SD) of the ERMI values in the homes of the NC asthmatic children was 16.4 (6.77), compared to the HUD survey VB ERMI value mean and SD of 11.2 (6.72), and was significantly greater (t-test, p = 0.003) in the NC asthmatic children's homes. The molds Chaetomium globosum, Aspergillus fumigatus, and the Eurotium Group were the primary species in the NC homes of asthmatics, making the ERMI values significantly higher (p < 0.02 for each). Vacuum bag dust analysis may be a useful method for estimating the mold burden in a home.

Indoor environmental quality in homes of asthmatic children on the Elsipogtog Reserve (NB), Canada

Objective. To inspect houses and analyze settled dust from 26 homes with asthmatic children in the Elsipogtog Reserve, New Brunswick, for contaminants known to be associated with respiratory symptoms. This pilot observational study was conducted in order to enable larger research into housing and health in Aboriginal communities.Methods. Twenty-six homes were subject to an informed inspection and settled dust collection from the child’s bedroom. The fine dust (< 300 µm) was analyzed for endotoxin, house dust mite and fungal glucan concentrations, as well as for building-associated fungi.Results. The percentage of homes in this study that had mould damage was slightly higher than in much larger studies in other parts of Canada. Qualitatively, the causes of the water and mould damage were similar to those found in a larger study in nearby PEI. However, in a few cases, the type of damage found in Elsipogtog was at a more advanced stage. House dust mite allergens, endotoxin and fungal glucan concentrations in settled dust included values that have been associated with increased respiratory symptoms. This selection of houses was, on average, cleaner than many homes studied in Canada.Conclusion. Although the range of mould damage observed in this study was similar to that seen elsewhere in Canada, the underlying causes tended to reflect more serious maintenance problems. A systematic evaluation of mould damage, on a community-wide basis, is a useful process to set priorities for repair. (Int J Circumpolar Health 2005; 64(1):77–85)

Indoor exposures to air pollutants and allergens in the homes of asthmatic children in inner-city Baltimore

This paper presents indoor air pollutant concentrations and allergen levels collected from the homes of 100 Baltimore city asthmatic children participating in an asthma intervention trial. Particulate matter (PM), NO 2, and O 3 samples were collected over 72 h in the child's sleeping room. Time-resolved PM was also assessed using a portable direct-reading nephelometer. Dust allergen samples were collected from the child's bedroom, the family room, and the kitchen. The mean PM 10 concentration, 56.5±40.7 μg/m 3, is 25% higher than the PM 2.5 concentration ( N = 90 ), 45.1±37.5 μg/m 3. PM concentrations measured using a nephelometer are consistent and highly correlated with gravimetric estimates. Smoking households’ average PM 2.5 and PM 10 concentrations are 33–54 μg/m 3 greater than those of nonsmoking houses, with each cigarette smoked adding 1.0 μm/m 3 to indoor PM 2.5 and PM 10 concentrations. Large percentages of NO 2 and O 3 samples, 25% and 75%, respectively, were below the limit of detection. The mean NO 2 indoor concentration is 31.6±40.2 ppb, while the mean indoor O 3 concentration in the ozone season was 3.3±7.7 ppb. The levels of allergens are similar to those found in other inner cities. Results presented in this paper indicate that asthmatic children in Baltimore are exposed to elevated allergens and indoor air pollutants. Understanding this combined insult may help to explain the differential asthma burden between inner-city and non-inner-city children.

Predictors of indoor allergen

Rationale Indoor allergens can significantly increase morbidity in atopic children with asthma. The purpose of this study was to relate allergen-specific home characteristics to measured allergen levels in the homes of asthmatic children. Methods As part of an ongoing environmental intervention study, pet, cockroach, and dust mite allergen levels were collected from the homes of 341 children. Trained inspectors documented characteristics of homes located in suburban Maryland (76%) and Baltimore City (23%). We used factor analyses and linear regressions to explore the relationship between evidence found during home inspection and allergen levels. Results Factor analyses identified groups of independent home characteristics associated with each allergen. The combined evidence of roaches, plumbing leaks, dirty cooking pots and city dwelling was significantly associated with cockroach allergen levels (t=8.6, p<0.00). However, poor kitchen cleanliness, including exposed food and surface clutter, was less clearly associated (t=1.8, p=0.08). The presence of surface clutter, detached home, and infrequent cleaning of the bedroom floor were significantly associated with dust mite allergen levels (t=2.8, p=0.01). Presence of mattress/pillow encasements, however, did not predict dust mite allergen levels. Evidence of pet ownership (t=7.7, p<0.00), detached home in a suburban setting and infrequent washing of bedding statistically predicted pet allergen levels (t=3.4, p<0.00). Conclusions Analysis of a large cohort study demonstrated that cockroach allergen could be predicted by infestation, plumbing leaks and greasy stoves, but not by kitchen debris. Mite allergen was predicted by infrequent cleaning and surface clutter, but was unaffected by presence of mattress or pillow encasements.

Health effects of ultraviolet irradiation in asthmatic children's homes

Rationale Indoor mold exposure can aggravate allergic rhinitis/asthma. We report baseline data investigating the effect of central ultraviolet (UV) irradiation (CREON2000) in asthmatic children. Methods Twenty mold-sensitized asthmatic children aged 5–17 with central heating and ventilation systems were enrolled in a 24 week double-blinded placebo controlled cross-over trial. Subjects recorded daily indoor and outdoor AM/PM rhinitis and asthma symptom scores (SS) and peak expiratory flow rates (PEFRs). Half the homes received a sham and the other half an active CREON2000 unit. Dew point and temperature are being continuously monitored in and outdoors. At 12 weeks, active units are being exchanged for sham units and vice-versa. Air sampling for mold/bacteria and dust sampling for perennial allergens and endotoxin is being collected at baseline, crossover and completion. The primary endpoint is reduction in rhinitis/asthma exacerbations. Regression analysis will evaluate relationships between environmental exposures, symptoms, PEFRs and quality of life pre- and post-intervention. Results Patient demographics were: Avg Age=10; M:F=13:7; Cauc:AfrAm=14:6. Baseline mean biweekly total indoor rhinitis/asthma SS were 127 ± 96/77 ± 78 and outdoor rhinitis/asthma SS were 64 ± 48/40 ± 40. Baseline mean daily PEFR variability was 6%. Baseline mean outdoor/indoor mold levels were 1054 ± 1187/469 ± 850 CFU/m 3 and outdoor/indoor bacteria levels were 506 ± 1115/697 ± 618 CFU/m 3. Baseline dust analysis revealed moderate to high levels of mold allergen (μg/gm of dust) in 10/20 homes and perennial allergens in 11/20 homes. Conclusion Completion of this prospective study will determine the effect of UV irradiation on indoor mold and bacteria levels and potential health effects in asthmatic children.

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

BackgroundThe contribution of indoor fungal exposure to childhood asthma is not completely clear ObjectiveTo investigate airborne fungal flora within the homes of asthmatic and control children, and to assess the influence of housing characteristics regarding indoor fungi MethodsForty-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 ResultsThe 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 ConclusionFungal 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

Exposure Levels of Asthmatic Children to Allergens, Endotoxins, and Serine Proteases in a Tropical Environment

A cross‐sectional study was conducted in Bayamón, Puerto Rico, to identify and quantify indoor allergens, serine proteases, and bacterial endotoxin present in homes of asthmatic children. A total of 126 dust samples from houses were obtained from the entire mattress and bedside floor. Most of the patients had detectable levels of mite, cockroach, cat, and dog allergens. Mold allergens were found only in bedside floor dust samples. Mouse allergens were not detected. Forty‐two percent, 36.5%, and 1.8% of the patients demonstrated exposures to sensitizing levels of mite, Bla g 1 and cat allergens, respectively. The percentage of patients exposed to high levels of allergens capable of triggering asthma symptoms was 33.3% and 26.4% for mite and Bla g 1 allergens. Only dog allergen, bacterial endotoxin, elastase, and trypsin were associated with asthma symptoms. Eighty‐nine percent of the asthmatic children were exposed to endotoxin concentrations greater than 100 EU/mg dust, and more than half of the patients were exposed to high levels of serine proteases. Our study indicates that indoor concentrations of allergens traditionally associated with asthma symptoms and severity may not be applicable in tropical environments and highly ventilated households. In fact, in the study population, endotoxins, dog allergen, and serine proteases may play a dominant role in the induction of asthma symptoms.

Dust mite, cockroach, cat, and dog allergen concentrations in homes of asthmatic children in the northeastern United States: impact of socioeconomic factors and population density.

Home exposures to aeroallergens are an important environmental factor in allergic sensitization and in the development and exacerbation of asthma. We assessed variations in home concentrations of dust mite, cockroach, cat, and dog allergens in dust collected in the main living areas of asthmatics' homes by family income, mother's education, dwelling type, population density, household population density, and ethnicity in Connecticut and south-central Massachusetts. Dust samples were collected at the time of home interview in 999 homes as part of an ongoing longitudinal birth cohort study of 1,002 infants and their asthmatic siblings. The analysis employed lower and upper cut points for group 1 dust mite (> or = 2.0 microg/g and > or = 10 microg/g), cockroach (> or = 1.0 U/g and > or = 4.0 U/g), cat (> or = 1.0 microg/g and > or = 8.0 ug/g), and dog (> or = 2.0 microg/g and > or = 10.0 microg/g) allergens. Subject residences were geocoded to assess population density from the U.S. Census, and multiple logistic regression was used to control for confounding. The portion of homes at the lower cut point for dust mite, cockroach, cat, and dog allergens were 46.9%, 24.9%, 42.2%, and 35.6%, respectively; the upper cut point for each of the allergens was reached in 22.4%, 13.4%, 21.0%, and 22.9% of the homes, respectively. In all, 86.0% of the homes had at least one allergen at the lower cut point, and 58.0% had at least one allergen at the upper cut point. Forty-nine percent of the homes had two or more allergens at the lower cut point, and 19.7% had two or more allergens at the upper cut point. Higher education of the mother, higher household income, living in a single-family home in a less densely populated area with fewer people per room, and being a white household were associated with elevated dust mite, cat, and dog allergens and low cockroach allergen. In contrast, low income, living in a multifamily home in a high population density area with a higher occupancy rate per room, and being a Hispanic or black household were associated with elevated cockroach allergens and low concentrations of dust mite, cat, and dog allergens. Although the presence of an individual allergen is more likely associated with one or more socioeconomic or ethnic factors, most homes typically have multiple allergen burdens in excess of concentrations thought to be associated with sensitization and exacerbation of asthma. Mite and cockroach allergens have distinct and opposite associations with socioeconomic factors and population density.

Distribution variations of multi allergens at asthmatic children's homes

Increasing asthma prevalence is evident in many countries and childhood asthma has also become one of the most common chronic diseases in children. Exposure to indoor allergens has been be attributed to a significant increase in asthma occurrence. Meanwhile, allergen distribution varies widely among different countries. This brief investigation reports the distribution of common indoor allergens, such as mite ( Dermatophagoides pteronyssinus, Der p 1 and Der p 2), cat ( Felis domesticus, Fel d 1), and German cockroach allergens ( Blattella germanica, Bla g 1) at different sites of asthmatic children in Taiwan. Approximately 40 asthmatic children's homes participated in this study and the cohort was followed prospectively for approximately 6 months, starting in December until the following May. Dust samples were collected from each child's mattress, and bedroom and living room floors. All samples were analyzed with monoclonal antibody-based enzyme-linked immunosorbent assay (ELISA). Statistical difference of Der p 1 concentrations is observed among those on the mattress, bedroom and living room floor, except for in May. Seasonal variation in Der p 1 levels on the mattress and bedroom floor is also significant ( P<0.025 and 0.001, respectively). Distributional variation seems to be significant for most allergens among sites within homes in most seasons. Therefore, if only one sample is to be taken, the month of May would be a more ideal choice of study period, and detailed sampling across sites appears to be necessary should the true environmental exposure of allergens be desired.

Book Review: Clinical Effects of Air Cleaners in Homes of Asthmatic Children Sensitized to Pet Allergens

Book Review: Clinical Effects of Air Cleaners in Homes of Asthmatic Children Sensitized to Pet Allergens

The Melbourne House Dust Mite Study: Long-term efficacy of house dust mite reduction strategies

Background: Asthma severity among mite-sensitized individuals appears to be related to the degree of mite allergen exposure. Objectives: The objective of this study was to assess the long-term effectiveness of mite avoidance measures in the homes of asthmatic children in Melbourne, Australia. Methods: The concentration of house dust mite allergen (Der p 1) was measured on the child's mattress surfaces and bedroom floors in 85 homes on 10 occasions over a 16-month period. After the first three visits, all mattresses were covered with a semipermeable encasement, and carpeted bedroom floors were randomly allocated to regular applications of a placebo or an “anti-mite” shampoo. Results: The concentration of Der p 1 recovered was initially high in the carpeted bedrooms ( n = 66) (41.1, 95% confidence interval, 30.7 to 55.0 μg Der p 1 per gm) and mattresses ( n = 85) (39.6, 27.2 to 57.7). During the initial observation period the concentration of mite allergen fell in the treatment, placebo, and parental control groups. During the seven treatment periods, no differences were seen between the Der p 1 concentrations in the groups using the “anti-mite” shampoo, placebo shampoo, or the parental control group (e.g., at visit 4; 12.6, 8.2 to 19.5; 14.8, 8.6 to 25.1; and 12.0, 8.1 to 17.7 μg/gm, respectively). In contrast, the concentration of Der p 1 in samples from uncarpeted floors and mattress encasements was low (4.1, 2.1 to 8.0 μg/gm and 4.2, 2.6 to 6.5 μg/gm, respectively) and insufficient dust for analysis was frequently obtained from these sites. Conclusions: There was no additional benefit from the use of an “anti-mite” shampoo. The absence of carpets and the use of mattress encasements was a useful long-term strategy for mite allergen avoidance.

Towards prevention

Towards prevention

Measurement of airborne mite antigen in homes of asthmatic children

The airborne concentration of major house dust mite antigen Der p1 was measured by low volume sampling (2 litres/min) in the homes of 68 allergic, asthmatic children. The presence of detectable airborne antigen was strongly associated with sensitivity to the mite, whereas there was no significant relation between sensitivity and the previously recommended threshold level of 2 μg Der p1 per g carpet dust. There was a significant association with lower threshold levels in carpet dust (0·5 μg/g) but at no level was the association as strong as that with air measurements. Concentrations of airborne antigen were higher in rooms with wool carpets than in those with synthetic carpets or hard floors, but there was no significant difference between the dust levels of Der p1 in the two carpet types. Air sampling is a more appropriate method of assessing antigen exposure than dust sampling for asthmatic patients.