MEDLINE Abstracts: Environmental Influences on Asthma - The Role of Indoor Allergens
MEDLINE Abstracts: Environmental Influences on Asthma - The Role of Indoor Allergens
What's new concerning the impact of indoor allergens on asthma? Find out in this easy-to-navigate collection of recent MEDLINE abstracts compiled by the editors at Medscape Pulmonary Medicine.
Authors Zhang L, Chew FT, Soh SY, Yi FC, Law SY, Goh DY, Lee BW
Clinical & Experimental Allergy 27(8):876-85, 1997 Aug
BACKGROUND AND AIMS: Immediate hypersensitivity to indoor allergens is known to be associated with allergic asthma. This study evaluated the prevalence and distribution of six indoor allergens in 956 dust samples obtained from homes, childcare centres, schools, and a hospital in tropical Singapore. Seasonality of mite allergens was also assessed.
METHODS: The major allergens of the Dermatophagoides spp. dust mites, Der p 1 and Der f 1; major cat and dog allergens, Can f 1 (dog) and Fel d 1 (cat); and cockroach, Bla g 1, were measured by specific enzyme immunoassays. Allergen levels of the storage mite, Blomia tropicalis (Blot), were measured by a fluorescent allergosorbent test (FAST) inhibition assay.
RESULTS: Our results showed that homes had significantly higher concentrations and prevalence of allergens compared with the other locations, except for Bla g 1, where higher mean levels were found in schools. Within the homes, the highest concentrations of mite allergens were found in mattresses (geometric mean: 1.2 microg/g dust Der p 1; 2717 Allergen Units per gram dust [AU/g] Blo t), and carpets (1.5 microg/g Der p 1; 1620 AU/g Blo t), whilst Bla g 1 was mainly concentrated in the storerooms (geometric mean = 3.5 units/g) and kitchens (geometric mean = 5.1 units/g). The major cat and dog allergens were well distributed and not confined to homes with pets. Their highest levels were found in dust of soft furnishings, carpets and mattresses. There was an absence of significant seasonal variation in Der p 1, Der f 1 and Blo t levels in the homes over a 1 year period.
CONCLUSION: The results indicate that compared with public places, the home consitutes a major reservior of indoor allergens. Allergens of the storage mite, B. tropicalis, should be considered as a major allergenic component of dust in Singapore.
Maier WC, Arrighi HM, Morray B, Llewellyn C, Redding GJ
Environmental Health Perspectives 105(2):208-14, 1997 Feb
Indoor risk factors for physician-diagnosed asthma and wheezing in the past 12 months without previous asthma diagnosis were assessed in a survey of parents of 5-9-year-old Seattle primary school students. Among the 925 respondents, 106 (11%) reported a physician diagnosis of asthma, 66 (7%) had wheezing without diagnosis, and 753 (82%) were asymptomatic. After adjusting for age, sex, gender, ethnicity, medical history, socioeconomic status (SES) and parental asthma status, an increased risk of physician diagnosis of asthma was associated with household water damage, the presence of one or more household tobacco smokers, and at least occasional environmental tobacco smoke (ETS) exposure. Similarly, an increased risk of wheezing in the past 12 months among children without diagnosed asthma was associated with household water damage, presence of one or more household tobacco smokers, and occasional or more frequent ETS exposure. No increased risk of either condition was associated with gas, wood, or kerosene stove use, household mold, basement water, or wall/window dampness. Similarities in the indoor risk factors patterns between diagnosed asthma and wheezing without diagnosis suggested a similar etiology of these two conditions. The slightly higher association between ETS and asthma may indicate that parents of diagnosed asthmatics were more conscious of ETS, and were more likely to prohibit household smoking by resident smokers. Future research is needed to quantify which aspects of household water damage are related to respiratory illness.
de Blay F, Sanchez J, Hedelin G, Perez-Infante A, Verot A, Chapman M, Pauli G
Journal of Allergy & Clinical Immunology 99(1 Pt 1):107-12, 1997 Jan
BACKGROUND: Although a strong association between allergy to cockroach (CR) and asthma has been observed in the United States and Asia, there are little data about the extent of exposure to CR allergen in Europe.
OBJECTIVE: To determine the levels of CR allergens in dust samples from apartments in Strasbourg and to determine the concentration and size of CR allergens in the air.
METHODS: Nine apartments in a public housing complex were chosen on the basis of visual evidence of CR infestation. Levels of CR allergens (Bla g 1 and Bla g 2) in kitchen and mattress dust samples were measured by immunoassay with the use of monoclonal antibodies. Air was sampled for 3 to 8 hours in the kitchen under undisturbed conditions, during artificial disturbance, and during normal domestic activity by using an impinger and a parallel glass fiber filter and at flow rates of 2 to 20 L/min. Airborne CR and mite allergens were measured concurrently in the bedroom of one apartment before, during, and after artificial disturbance.
RESULTS: High levels of Bla g 1 and Bla g 2 were found in kitchen dust from the nine apartments (geometric means of 3919 U/gm [range 530 to 14306 U/gm] and 497 U/gm [range 73 to 1946 U/gm], respectively). Under undisturbed conditions, airborne CR allergens were not detectable in any of the apartments. During vigorous artificial disturbance, Bla g 1 and Bla g 2 were detectable in air samples from seven apartments (geometric means of 4.5 U/m3 [range 0.7 to 17.2 U/m3] and 1.0 U/m3 [range 0.4 to 3.4 U/m3], respectively). Both allergens were predominantly collected on the first stage of the impinger, and 76% to 80% of the airborne allergen was associated with particles greater than 10 microns in diameter. The levels were significantly higher than those collected on the second or third stages of the impinger (p < 0.001). A comparison of the levels of mite and CR allergens showed that the airborne properties of these allergens were similar, that is, measurable only during disturbance and not detectable 30 minutes after disturbance.
CONCLUSION: Levels of CR allergen in low-cost public housing in Strasbourg can be as high as or higher than the levels measured in towns in the United States. CR allergens become airborne during disturbance and are primarily associated with particles greater than 10 microns in diameter. Patients with asthma living in urban areas of Europe in housing prone to CR infestation should be evaluated for sensitization and exposure to CR allergens.
Platts-Mills TA, Sporik RB, Chapman MD, Heymann PW
Ciba Foundation Symposium 206:173-85; discussion 185-9, 1997
The documented increase in asthma has been almost entirely in perennial asthma and a large proportion of the cases are allergic to one of the common allergens found all year round in houses, i.e. house dust mites, cats, dogs or cockroaches. In population and case-control studies sensitization to one of these allergens is the strongest risk factor for asthma (adjusted odds ratios > or = 4). Using monoclonal antibody-based assays for the major indoor allergens it has been shown that sensitization to house dust mites is directly related to the concentration of Group 1 mite allergen in dust. This led to the hypothesis that increases in mite allergen secondary to changes in houses were responsible for increases in asthma. However, asthma has also increased in areas of the world where mites do not flourish. In these dry areas sensitization to one of the other indoor allergens is the major risk factor for asthma. Although sensitization of asthmatics reflects the concentration of allergens in their houses, these measurements of exposure do not accurately predict severity of symptoms. Other factors that can contribute to the symptoms of asthma may also have increased. In particular, diesel particulates, ozone, beta 2-agonists, endotoxin and rhinovirus infection have each been shown to enhance the inflammatory response to inhaled allergens. Increases in asthma must relate to some aspect of our predominantly sedentary indoor lifestyle; this could be either increased exposure to allergens or an increase in factors that enhance the response of the lungs to foreign proteins.
van der Heide S, De Monchy JG, De Vries K, Dubois AE, Kauffman HF
Clinical & Experimental Allergy 27(6):627-33, 1997 Jun
BACKGROUND: The degree of airway hyperresponsiveness in allergic asthmatic patients may be influenced by changes in environmental exposure to inhalant allergens.
OBJECTIVE: This study investigates the relationship between seasonal changes in exposure to house dust mite (HDM) allergens and non-specific airway hyperresponsiveness in asthmatic patients with multiple sensitizations to inhaled allergens.
METHODS: In 43 asthmatic patients sensitized to several inhalant allergens, lung function (FEV1), airway hyperresponsiveness (PC20 histamine), serum total IgE, house dust mite (HDM) specific IgE and number of peripheral blood eosinophils were measured during autumn 1990 (September-November) and spring 1991 (March-May). During each season, floor dust samples were collected twice from living- and bedrooms and the concentration of the HDM allergens Der p 1 and Der p 2 determined.
RESULTS: More severe airway hyperresponsiveness (lower PC20 histamine) during autumn was only found in patients sensitized to HDM (n = 32; autumn: 2.05 mg/mL, spring: 4.51 mg/mL (geometric means), P < 0.01), whereas in patients not sensitized to HDM (n = 11) similar values were observed in both seasons (3.44 and 4.52 mg/mL, respectively, P = 0.56). More severe airway hyperresponsiveness of HDM sensitized patients in autumn was significantly associated with higher Der p 1 concentrations in floor dust. Aside from airway hyperresponsiveness, seasonal changes in serum total IgE and number of peripheral blood eosinophils were seen in patients sensitized to HDM.
CONCLUSIONS: In allergic asthmatic patients, airway hyperresponsiveness may increase during autumn, depending on sensitization to HDM and an increase of exposure to HDM allergen.
Rosenstreich DL, Eggleston P, Kattan M, Baker D, Slavin RG, Gergen P, Mitchell H, McNiff-Mortimer K, Lynn H, Ownby D, Malveaux F
New England Journal of Medicine 336(19):1356-63, 1997 May 8
BACKGROUND: It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust.
METHODS: From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period.
RESULTS: Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen.
CONCLUSIONS: The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.
Hill DJ, Thompson PJ, Stewart GA, Carlin JB, Nolan TM, Kemp AS, Hosking CS
Journal of Allergy & Clinical Immunology 99(3):323-9, 1997 Mar
BACKGROUND: Hypersensitivity to house dust mite allergens is associated with increased asthma morbidity. Asthma severity appears to be related to the degree of mite allergen exposure. Short-term studies suggest that complete avoidance reduces disease severity.
OBJECTIVE: The study was designed to assess the effect of different mattress covers and floor coverings on mite allergen concentrations in the homes of mite-sensitive children with asthma in the city of Melbourne, Australia.
METHODS: Mite allergen Der p 1 concentration was measured on mattress covers, mattress surfaces, and carpeted and uncarpeted floors in 107 dwellings; and measurement was performed on three occasions over a 5-month period. After the first sampling, all mattress covers and impermeable encasements were permanently removed.
RESULTS: The initial geometric mean concentrations of Der p 1 (micrograms per gram of fine dust) from the surfaces of sheepskin, wool, and cotton mattress coverings were greater than those from the surfaces of impermeable mattress encasements (116, 113, and 19 vs 0.4) (p < 0.001); corresponding concentrations on the underlying mattresses were142, 38, 20, and 0.6, respectively (p < 0.05 to 0.001). At the end of the study these mattress surface concentrations were 79, 65, 9.7, and 3.1, respectively. In 24 dwellings an uncarpeted room was adjacent to a carpeted room. At each visit the concentration of Der p 1 in uncarpeted rooms was below the reported threshold for sensitization and significantly less than that in the adjacent carpeted room.
CONCLUSION: In homes of children with asthma, "asthmogenic" concentrations of Der p 1 were found on nonencased mattresses and carpeted floors, but the use of impermeable mattress encasements and carpet exclusion were associated with concentrations of Der p 1 below the reported threshold for sensitization.
Li CS, Hsu LY
Archives of Environmental Health 52(1):72-9, 1997 Jan-Feb
Airborne fungi were collected during the summer and winter seasons. A N6 Andersen sampler was used inside and outside the homes of 46 asthmatic children, 20 atopic children, and 26 nonatopic control children in the Taipei area. In addition, host and house characteristics were obtained by questionnaire. The indoor fungus concentrations of asthmatic and control groups were higher than those in atopic groups in summer, but there were no differences in total fungus concentrations among three groups in winter. Concentration differences among these three groups also occurred for Cladosporium and Penicillium in summer and for Aspergillus, Cladosporium, Penicillium, and yeast in the winter. Moreover, it was demonstrated that no differences in fungus concentration were observed between damp and dry homes. Penicillium concentrations appeared to be related to home dampness. Home dampness was associated with allergic symptoms in children with asthma and rhinitis. An association was also observed between the occurrence of Cladosporium and history of asthma.
What's new concerning the impact of indoor allergens on asthma? Find out in this easy-to-navigate collection of recent MEDLINE abstracts compiled by the editors at Medscape Pulmonary Medicine.
Authors Zhang L, Chew FT, Soh SY, Yi FC, Law SY, Goh DY, Lee BW
Clinical & Experimental Allergy 27(8):876-85, 1997 Aug
BACKGROUND AND AIMS: Immediate hypersensitivity to indoor allergens is known to be associated with allergic asthma. This study evaluated the prevalence and distribution of six indoor allergens in 956 dust samples obtained from homes, childcare centres, schools, and a hospital in tropical Singapore. Seasonality of mite allergens was also assessed.
METHODS: The major allergens of the Dermatophagoides spp. dust mites, Der p 1 and Der f 1; major cat and dog allergens, Can f 1 (dog) and Fel d 1 (cat); and cockroach, Bla g 1, were measured by specific enzyme immunoassays. Allergen levels of the storage mite, Blomia tropicalis (Blot), were measured by a fluorescent allergosorbent test (FAST) inhibition assay.
RESULTS: Our results showed that homes had significantly higher concentrations and prevalence of allergens compared with the other locations, except for Bla g 1, where higher mean levels were found in schools. Within the homes, the highest concentrations of mite allergens were found in mattresses (geometric mean: 1.2 microg/g dust Der p 1; 2717 Allergen Units per gram dust [AU/g] Blo t), and carpets (1.5 microg/g Der p 1; 1620 AU/g Blo t), whilst Bla g 1 was mainly concentrated in the storerooms (geometric mean = 3.5 units/g) and kitchens (geometric mean = 5.1 units/g). The major cat and dog allergens were well distributed and not confined to homes with pets. Their highest levels were found in dust of soft furnishings, carpets and mattresses. There was an absence of significant seasonal variation in Der p 1, Der f 1 and Blo t levels in the homes over a 1 year period.
CONCLUSION: The results indicate that compared with public places, the home consitutes a major reservior of indoor allergens. Allergens of the storage mite, B. tropicalis, should be considered as a major allergenic component of dust in Singapore.
Maier WC, Arrighi HM, Morray B, Llewellyn C, Redding GJ
Environmental Health Perspectives 105(2):208-14, 1997 Feb
Indoor risk factors for physician-diagnosed asthma and wheezing in the past 12 months without previous asthma diagnosis were assessed in a survey of parents of 5-9-year-old Seattle primary school students. Among the 925 respondents, 106 (11%) reported a physician diagnosis of asthma, 66 (7%) had wheezing without diagnosis, and 753 (82%) were asymptomatic. After adjusting for age, sex, gender, ethnicity, medical history, socioeconomic status (SES) and parental asthma status, an increased risk of physician diagnosis of asthma was associated with household water damage, the presence of one or more household tobacco smokers, and at least occasional environmental tobacco smoke (ETS) exposure. Similarly, an increased risk of wheezing in the past 12 months among children without diagnosed asthma was associated with household water damage, presence of one or more household tobacco smokers, and occasional or more frequent ETS exposure. No increased risk of either condition was associated with gas, wood, or kerosene stove use, household mold, basement water, or wall/window dampness. Similarities in the indoor risk factors patterns between diagnosed asthma and wheezing without diagnosis suggested a similar etiology of these two conditions. The slightly higher association between ETS and asthma may indicate that parents of diagnosed asthmatics were more conscious of ETS, and were more likely to prohibit household smoking by resident smokers. Future research is needed to quantify which aspects of household water damage are related to respiratory illness.
de Blay F, Sanchez J, Hedelin G, Perez-Infante A, Verot A, Chapman M, Pauli G
Journal of Allergy & Clinical Immunology 99(1 Pt 1):107-12, 1997 Jan
BACKGROUND: Although a strong association between allergy to cockroach (CR) and asthma has been observed in the United States and Asia, there are little data about the extent of exposure to CR allergen in Europe.
OBJECTIVE: To determine the levels of CR allergens in dust samples from apartments in Strasbourg and to determine the concentration and size of CR allergens in the air.
METHODS: Nine apartments in a public housing complex were chosen on the basis of visual evidence of CR infestation. Levels of CR allergens (Bla g 1 and Bla g 2) in kitchen and mattress dust samples were measured by immunoassay with the use of monoclonal antibodies. Air was sampled for 3 to 8 hours in the kitchen under undisturbed conditions, during artificial disturbance, and during normal domestic activity by using an impinger and a parallel glass fiber filter and at flow rates of 2 to 20 L/min. Airborne CR and mite allergens were measured concurrently in the bedroom of one apartment before, during, and after artificial disturbance.
RESULTS: High levels of Bla g 1 and Bla g 2 were found in kitchen dust from the nine apartments (geometric means of 3919 U/gm [range 530 to 14306 U/gm] and 497 U/gm [range 73 to 1946 U/gm], respectively). Under undisturbed conditions, airborne CR allergens were not detectable in any of the apartments. During vigorous artificial disturbance, Bla g 1 and Bla g 2 were detectable in air samples from seven apartments (geometric means of 4.5 U/m3 [range 0.7 to 17.2 U/m3] and 1.0 U/m3 [range 0.4 to 3.4 U/m3], respectively). Both allergens were predominantly collected on the first stage of the impinger, and 76% to 80% of the airborne allergen was associated with particles greater than 10 microns in diameter. The levels were significantly higher than those collected on the second or third stages of the impinger (p < 0.001). A comparison of the levels of mite and CR allergens showed that the airborne properties of these allergens were similar, that is, measurable only during disturbance and not detectable 30 minutes after disturbance.
CONCLUSION: Levels of CR allergen in low-cost public housing in Strasbourg can be as high as or higher than the levels measured in towns in the United States. CR allergens become airborne during disturbance and are primarily associated with particles greater than 10 microns in diameter. Patients with asthma living in urban areas of Europe in housing prone to CR infestation should be evaluated for sensitization and exposure to CR allergens.
Platts-Mills TA, Sporik RB, Chapman MD, Heymann PW
Ciba Foundation Symposium 206:173-85; discussion 185-9, 1997
The documented increase in asthma has been almost entirely in perennial asthma and a large proportion of the cases are allergic to one of the common allergens found all year round in houses, i.e. house dust mites, cats, dogs or cockroaches. In population and case-control studies sensitization to one of these allergens is the strongest risk factor for asthma (adjusted odds ratios > or = 4). Using monoclonal antibody-based assays for the major indoor allergens it has been shown that sensitization to house dust mites is directly related to the concentration of Group 1 mite allergen in dust. This led to the hypothesis that increases in mite allergen secondary to changes in houses were responsible for increases in asthma. However, asthma has also increased in areas of the world where mites do not flourish. In these dry areas sensitization to one of the other indoor allergens is the major risk factor for asthma. Although sensitization of asthmatics reflects the concentration of allergens in their houses, these measurements of exposure do not accurately predict severity of symptoms. Other factors that can contribute to the symptoms of asthma may also have increased. In particular, diesel particulates, ozone, beta 2-agonists, endotoxin and rhinovirus infection have each been shown to enhance the inflammatory response to inhaled allergens. Increases in asthma must relate to some aspect of our predominantly sedentary indoor lifestyle; this could be either increased exposure to allergens or an increase in factors that enhance the response of the lungs to foreign proteins.
van der Heide S, De Monchy JG, De Vries K, Dubois AE, Kauffman HF
Clinical & Experimental Allergy 27(6):627-33, 1997 Jun
BACKGROUND: The degree of airway hyperresponsiveness in allergic asthmatic patients may be influenced by changes in environmental exposure to inhalant allergens.
OBJECTIVE: This study investigates the relationship between seasonal changes in exposure to house dust mite (HDM) allergens and non-specific airway hyperresponsiveness in asthmatic patients with multiple sensitizations to inhaled allergens.
METHODS: In 43 asthmatic patients sensitized to several inhalant allergens, lung function (FEV1), airway hyperresponsiveness (PC20 histamine), serum total IgE, house dust mite (HDM) specific IgE and number of peripheral blood eosinophils were measured during autumn 1990 (September-November) and spring 1991 (March-May). During each season, floor dust samples were collected twice from living- and bedrooms and the concentration of the HDM allergens Der p 1 and Der p 2 determined.
RESULTS: More severe airway hyperresponsiveness (lower PC20 histamine) during autumn was only found in patients sensitized to HDM (n = 32; autumn: 2.05 mg/mL, spring: 4.51 mg/mL (geometric means), P < 0.01), whereas in patients not sensitized to HDM (n = 11) similar values were observed in both seasons (3.44 and 4.52 mg/mL, respectively, P = 0.56). More severe airway hyperresponsiveness of HDM sensitized patients in autumn was significantly associated with higher Der p 1 concentrations in floor dust. Aside from airway hyperresponsiveness, seasonal changes in serum total IgE and number of peripheral blood eosinophils were seen in patients sensitized to HDM.
CONCLUSIONS: In allergic asthmatic patients, airway hyperresponsiveness may increase during autumn, depending on sensitization to HDM and an increase of exposure to HDM allergen.
Rosenstreich DL, Eggleston P, Kattan M, Baker D, Slavin RG, Gergen P, Mitchell H, McNiff-Mortimer K, Lynn H, Ownby D, Malveaux F
New England Journal of Medicine 336(19):1356-63, 1997 May 8
BACKGROUND: It has been hypothesized that asthma-related health problems are most severe among children in inner-city areas who are allergic to a specific allergen and also exposed to high levels of that allergen in bedroom dust.
METHODS: From November 1992 through October 1993, we recruited 476 children with asthma (age, four to nine years) from eight inner-city areas in the United States. Immediate hypersensitivity to cockroach, house-dust-mite, and cat allergens was measured by skin testing. We then measured major allergens of cockroach (Bla g 1), dust mites (Der p 1 and Der f 1), and cat dander (Fel d 1) in household dust using monoclonal-antibody-based enzyme-linked immunosorbent assays. High levels of exposure were defined according to proposed thresholds for causing disease. Data on morbidity due to asthma were collected at base line and over a one-year period.
RESULTS: Of the children, 36.8 percent were allergic to cockroach allergen, 34.9 percent to dust-mite allergen, and 22.7 percent to cat allergen. Among the children's bedrooms, 50.2 percent had high levels of cockroach allergen in dust, 9.7 percent had high levels of dust-mite allergen, and 12.6 percent had high levels of cat allergen. After we adjusted for sex, score on the Child Behavior Checklist, and family history of asthma, we found that children who were both allergic to cockroach allergen and exposed to high levels of this allergen had 0.37 hospitalization a year, as compared with 0.11 for the other children (P=0.001), and 2.56 unscheduled medical visits for asthma per year, as compared with 1.43 (P<0.001). They also had significantly more days of wheezing, missed school days, and nights with lost sleep, and their parents or other care givers were awakened during the night and changed their daytime plans because of the child's asthma significantly more frequently. Similar patterns were not found for the combination of allergy to dust mites or cat dander and high levels of the allergen.
CONCLUSIONS: The combination of cockroach allergy and exposure to high levels of this allergen may help explain the frequency of asthma-related health problems in inner-city children.
Hill DJ, Thompson PJ, Stewart GA, Carlin JB, Nolan TM, Kemp AS, Hosking CS
Journal of Allergy & Clinical Immunology 99(3):323-9, 1997 Mar
BACKGROUND: Hypersensitivity to house dust mite allergens is associated with increased asthma morbidity. Asthma severity appears to be related to the degree of mite allergen exposure. Short-term studies suggest that complete avoidance reduces disease severity.
OBJECTIVE: The study was designed to assess the effect of different mattress covers and floor coverings on mite allergen concentrations in the homes of mite-sensitive children with asthma in the city of Melbourne, Australia.
METHODS: Mite allergen Der p 1 concentration was measured on mattress covers, mattress surfaces, and carpeted and uncarpeted floors in 107 dwellings; and measurement was performed on three occasions over a 5-month period. After the first sampling, all mattress covers and impermeable encasements were permanently removed.
RESULTS: The initial geometric mean concentrations of Der p 1 (micrograms per gram of fine dust) from the surfaces of sheepskin, wool, and cotton mattress coverings were greater than those from the surfaces of impermeable mattress encasements (116, 113, and 19 vs 0.4) (p < 0.001); corresponding concentrations on the underlying mattresses were142, 38, 20, and 0.6, respectively (p < 0.05 to 0.001). At the end of the study these mattress surface concentrations were 79, 65, 9.7, and 3.1, respectively. In 24 dwellings an uncarpeted room was adjacent to a carpeted room. At each visit the concentration of Der p 1 in uncarpeted rooms was below the reported threshold for sensitization and significantly less than that in the adjacent carpeted room.
CONCLUSION: In homes of children with asthma, "asthmogenic" concentrations of Der p 1 were found on nonencased mattresses and carpeted floors, but the use of impermeable mattress encasements and carpet exclusion were associated with concentrations of Der p 1 below the reported threshold for sensitization.
Li CS, Hsu LY
Archives of Environmental Health 52(1):72-9, 1997 Jan-Feb
Airborne fungi were collected during the summer and winter seasons. A N6 Andersen sampler was used inside and outside the homes of 46 asthmatic children, 20 atopic children, and 26 nonatopic control children in the Taipei area. In addition, host and house characteristics were obtained by questionnaire. The indoor fungus concentrations of asthmatic and control groups were higher than those in atopic groups in summer, but there were no differences in total fungus concentrations among three groups in winter. Concentration differences among these three groups also occurred for Cladosporium and Penicillium in summer and for Aspergillus, Cladosporium, Penicillium, and yeast in the winter. Moreover, it was demonstrated that no differences in fungus concentration were observed between damp and dry homes. Penicillium concentrations appeared to be related to home dampness. Home dampness was associated with allergic symptoms in children with asthma and rhinitis. An association was also observed between the occurrence of Cladosporium and history of asthma.
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