Indoor Environmental Exposures Research Articles

The effects of indoor environmental exposures on pediatric asthma: a discrete event simulation model.

BackgroundIn the United States, asthma is the most common chronic disease of childhood across all socioeconomic classes and is the most frequent cause of hospitalization among children. Asthma exacerbations have been associated with exposure to residential indoor environmental stressors such as allergens and air pollutants as well as numerous additional factors. Simulation modeling is a valuable tool that can be used to evaluate interventions for complex multifactorial diseases such as asthma but in spite of its flexibility and applicability, modeling applications in either environmental exposures or asthma have been limited to date.MethodsWe designed a discrete event simulation model to study the effect of environmental factors on asthma exacerbations in school-age children living in low-income multi-family housing. Model outcomes include asthma symptoms, medication use, hospitalizations, and emergency room visits. Environmental factors were linked to percent predicted forced expiratory volume in 1 second (FEV1%), which in turn was linked to risk equations for each outcome. Exposures affecting FEV1% included indoor and outdoor sources of NO2 and PM2.5, cockroach allergen, and dampness as a proxy for mold.ResultsModel design parameters and equations are described in detail. We evaluated the model by simulating 50,000 children over 10 years and showed that pollutant concentrations and health outcome rates are comparable to values reported in the literature. In an application example, we simulated what would happen if the kitchen and bathroom exhaust fans were improved for the entire cohort, and showed reductions in pollutant concentrations and healthcare utilization rates.ConclusionsWe describe the design and evaluation of a discrete event simulation model of pediatric asthma for children living in low-income multi-family housing. Our model simulates the effect of environmental factors (combustion pollutants and allergens), medication compliance, seasonality, and medical history on asthma outcomes (symptom-days, medication use, hospitalizations, and emergency room visits). The model can be used to evaluate building interventions and green building construction practices on pollutant concentrations, energy savings, and asthma healthcare utilization costs, and demonstrates the value of a simulation approach for studying complex diseases such as asthma.

Endotoxin as a determinant of asthma and wheeze among rural dwelling children and adolescents: a case-control study.

BackgroundThe association between endotoxin exposure and asthma is complex and has been associated with rural living. We examined the relationship between domestic endotoxin and asthma or wheeze among rural school-aged children (6–18 years) and assessed the interaction between endotoxin and other characteristics with these outcomes.MethodsBetween 2005 and 2007 we conducted a case–control study of children 6–18 years in the rural region of Humboldt, Canada. Cases (n = 102) reported doctor-diagnosed asthma or wheeze in the past year. Controls (n = 208) were randomly selected from children without asthma or wheeze. Data were collected to ascertain symptoms, asthma history and indoor environmental exposures (questionnaire), endotoxin (dust collection from the play area floor and child’s mattress), and tobacco smoke exposure (saliva collection). Statistical testing was completed using multiple logistic regression to account for potential confounders and to assess interaction between risk factors. A stratified analysis was also completed to examine the effect of personal history of allergy.ResultsAmong children aged 6–12 years, mattress endotoxin concentration (EU/mg) and load (EU/m2) were inversely associated with being a case [odds ratio (OR) = 0.44, 95% confidence interval (CI) = 0.20-0.98; and OR = 0.38, 95% CI = 0.20-0.75, respectively]. These associations were not observed in older children or with play area endotoxin.ConclusionsOur results suggest that endotoxin exposure might be protective for asthma or wheeze. The protective effect is found in younger school-aged, non-allergic children. These results may help explain the inconsistencies in previous studies and suggest that the protective effects of endotoxin in the prevention of atopy and asthma or wheeze are most effective earlier in life.

Indoor environmental exposures for children with asthma enrolled in the HEAL study, post-Katrina New Orleans.

Background: Rain and flooding from Hurricane Katrina resulted in widespread growth of mold and bacteria and production of allergens in New Orleans, Louisiana, which may have led to increased exposures and morbidity in children with asthma.Objectives: The goal of the Head-off Environmental Asthma in Louisiana (HEAL) study was to characterize post-Katrina exposures to mold and allergens in children with asthma.Methods: The homes of 182 children with asthma in New Orleans and surrounding parishes were evaluated by visual inspection, temperature and moisture measurements, and air and dust sampling. Air was collected using vacuum-pump spore traps and analyzed for > 30 mold taxa using bright field microscopy. Dust was collected from the children’s beds and bedroom floors and analyzed for mouse (Mus m 1), dust mite (Der p 1), cockroach (Bla g 1), and mold (Alternaria mix) allergens using ELISA.Results: More than half (62%) of the children were living in homes that had been damaged by rain, flooding, or both. Geometric mean indoor and outdoor airborne mold levels were 501 and 3,958 spores/m3, respectively. Alternaria antigen was detected in dust from 98% of homes, with 58% having concentrations > 10 µg/g. Mus m 1, Der p 1, and Bla g 1 were detected in 60%, 35%, and 20% of homes, respectively, at low mean concentrations.Conclusions: Except for Alternaria antigen in dust, concentrations of airborne mold (ratio of indoor to outdoor mold) and dust allergens in the homes of HEAL children were lower than measurements found in other studies, possibly because of extensive post-Katrina mold remediation and renovations, or because children moved into cleaner homes upon returning to New Orleans.

Determinants of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans in house dust samples from four areas of the United States

Determinants of levels of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/F) in dust in U.S. homes are not well characterized. We conducted a pilot study to evaluate the relationship between concentrations of PCDD/F in house dust and residential proximity to known sources, including industrial facilities and traffic. Samples from vacuum bag dust from homes of 40 residents of Detroit, Los Angeles, Seattle, or Iowa who participated in a population-based case–control study of non-Hodgkin lymphoma conducted in 1998–2000 were analyzed using high resolution gas chromatography/high resolution mass spectrometry for 7 PCDD and 10 PCDF congeners considered toxic by the U.S. Environmental Protection Agency (EPA). Locations of 10 types of PCDD/F-emitting facilities were obtained from the EPA; however only 4 types were located near study homes (non-hazardous waste cement kilns, coal-fired power plants, sewage sludge incinerators, and medical waste incinerators). Relationships between concentrations of each PCDD/F and proximity to industrial facilities, freight routes, and major roads were evaluated using separate multivariate regression models for each congener. The median (inter-quartile range [IQR]) toxic equivalence (TEQ) concentration of these congeners in the house dust was 20.3pg/g (IQR=14.3, 32.7). Homes within 3 or 5km of a cement kiln had 2 to 9-fold higher concentrations of 5 PCDD and 5 PCDF (p<0.1 in each model). Proximity to freight routes and major roads was associated with elevated concentrations of 1 PCDD and 8 PCDF. Higher concentrations of certain PCDD/F in homes near cement kilns, freight routes, and major roads suggest that these outdoor sources are contributing to indoor environmental exposures. Further study of the contribution of these sources and other facility types to total PCDD/F exposure in a larger number of homes is warranted.

Prediction of mold contamination from microbial volatile organic compound profiles using head space gas chromatography/mass spectrometry

A set of volatile organic compound (VOC) profiles was developed with corresponding bioaerosol measurements as input–output pairs for a discriminant to predict mold exposure in indoor environments. Entech Bottle-Vacs were used to collect whole air grab samples while viable spores were collected concurrently using an Andersen impactor in conjunction with malt extract agar and dichloran glycerol 18. By comparing the bioaerosol data to VOC profiles that were obtained using a GC/MS equipped with a cold trap preconcentrator, a discriminant was developed to classify a residence as to potential mold growth based on its microbial volatile organic (MVOC) profile.

Radon Concentrations in Various Indoor Environments and Effective Doses to Inhabitants in Korea

The objective of this study is to offer basic scientific data to support policy decision-making for the improved control of radon and natural radiation gases in Korea, and to provide baseline data on radon for use in cooperative international research. Therefore, this study collected and re-analyzed articles on radon exposure in various indoor environments in Korea that were published in environmental journals since 1980, and estimated the annual exposure and effective radon doses for inhabitants. Among the various indoor environments, the highest pooled average radon concentration of 50.17 ± 4.08 Bq/m3 (95 % CI: 42.17-58.17 Bq/m3) was found in homes. All of the pooled average radon concentrations estimated in this study were lower than the guideline concentration (148 Bq/m3) recommended by the U.S. EPA and the Korean Ministry of Environment. The annual effective dose received by inhabitants in various indoor environments was estimated to be 1.071 mSv/yr. This is comparable to the annual radon exposure effective dose (1.0 mSv/yr) estimated by UNSCEAR.

Moving Environmental Justice Indoors: Understanding Structural Influences on Residential Exposure Patterns in Low-Income Communities

The indoor environment has not been fully incorporated into the environmental justice dialogue. To inform strategies to reduce disparities, we developed a framework to identify the individual and place-based drivers of indoor environment quality. We reviewed empirical evidence of socioeconomic disparities in indoor exposures and key determinants of these exposures for air pollutants, lead, allergens, and semivolatile organic compounds. We also used an indoor air quality model applied to multifamily housing to illustrate how nitrogen dioxide (NO(2)) and fine particulate matter (PM(2.5)) vary as a function of factors known to be influenced by socioeconomic status. Indoor concentrations of multiple pollutants are elevated in low-socioeconomic status households. Differences in these exposures are driven by the combined influences of indoor sources, outdoor sources, physical structures, and residential activity patterns. Simulation models confirmed indoor sources' importance in determining indoor NO(2) and PM(2.5) exposures and showed the influence of household-specific determinants. Both theoretical models and empirical evidence emphasized that disparities in indoor environmental exposure can be significant. Understanding key determinants of multiple indoor exposures can aid in developing policies to reduce these disparities.

Early-life indoor environmental exposures increase the risk of childhood asthma

We aim to explore the relationships between exposure to dampness, pets, and environmental tobacco smoke (ETS) early in life and asthma in Taiwanese children, and to discuss their links to early- and late-onset asthma. We conducted a 1:2 matched case-control study from the Taiwan Children Health Study, which was a nationwide study that recruited 12-to-14 year-old school children in 14 communities. The 579 mothers of the participants were interviewed by telephone about their children's environmental exposures before they were 5 years old, including the in-utero period. Childhood asthma was associated with exposure to early life environmental factors, such as cockroaches (OR=2.16; 95% CI, 1.15-4.07), visible mould (OR=1.75; 95% CI, 1.15-2.67), mildewy odors (OR=5.04; 95% CI, 2.42-10.50), carpet (OR=2.36; 95% CI, 1.38-4.05), pets (OR=2.11; 95% CI, 1.20-3.72), and more than one hour of ETS per day (OR=1.93; 95% CI, 1.16-3.23). The ORs for mildewy odors, feather pillows, and ETS during early childhood were greater among children with late-onset asthma. Cockroaches, carpet, pets, and in-utero exposures to ETS affected the timing of early-onset asthma. Exposure to these factors led to dose-responsiveness in the risk of asthma. And the earlier exposures may trigger the earlier onset. Interventions in avoiding these environmental exposures are necessary for early-prevention of childhood asthma.

Abstract 1876: Assessment of exposure to potential lung carcinogens in Xuanwei and Fuyuan, China: Particulate exposure from cooking and heating stoves

Abstract Residents in Xuanwei, China have the highest lung cancer incidence rates in China for both men and women, despite the fact that almost all women are non-smokers. Several lines of research have provided strong support that the excess lung cancer rate in this region is caused primarily by emissions from smoky coal exposure. We have carried out a hospital-based case-control study of non-smoking female lung cancer in Xuanwei and its neighboring county, Fuyuan, to identify which constituents of coal combustion emissions and other indoor environmental exposures are causing the high lung cancer rates in this region. In order to develop individual estimates of exposure to known or suspected lung carcinogens, we designed a comprehensive exposure assessment study of 163 households in this region to evaluate exposure to PAHs, PM2.5, silica, and other exposures from coal and wood burning. Homes that used three main fuel types (i.e., smoky coal, smokeless coal and wood), and eight stove types [e.g., firepit, fixed or portable stove, with or without ventilation] were identified and households were sampled on two consecutive days. Up to 30 households were selected for each combination of fuel and stove type. A subgroup of 53 households was measured at two time-points during the study year (e.g. summer and winter). The female head of each household was asked to wear a 24-hour personal PM2.5 air sampler at the same time that 24-hour area air sampling was employed in the main living area. Personal and area particulate matter samples (PM2.5) were collected in each home. These samples were also used to quantify particle bound PAHs including BaP (by GC/MS), elemental components (by XRF and ICP/MS), and silica (by XRD). XAD2 samples were collected for the quantification of gaseous PAHs. Other samples, including radon and organic vapor, fuel and ash were also obtained. We also collected information on potential factors that could influence exposure, such as house characteristics, stove type, fuel type and use, amount of fuel used, amount of time spent in each room. Initial analyses show that people using wood burned in firepits were exposed to the highest levels of PM2.5 measured in area (536.3±370.5 µg/m3) and personal samples(419.8±283.3 µg/m3). Burning smokeless coal in a high stove with a chimney was associated with the lowest exposure to PM2.5 (62.2±34.1 µg/m3, 62.5±29.9 µg/m3 for area and personal samples, respectively). These data show that there is a wide range of exposure to PM2.5 in this population. These data and other exposure information from this study will be used in the future to model environmental exposures and risk of lung cancer in this special, high risk population. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 102nd Annual Meeting of the American Association for Cancer Research; 2011 Apr 2-6; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2011;71(8 Suppl):Abstract nr 1876. doi:10.1158/1538-7445.AM2011-1876

Mold exposure and respiratory health in damp indoor environments

Almost all modern buildings experience at least minor, and sometimes serious, water damage during their life span. Excess moisture in buildings becomes a critical factor for mold (fungal) proliferation in nutrient-rich environments. As a result, building occupants may be exposed to increased levels of microbial agents such as fungal spores, cell fragments, cell wall components, or toxins. Such exposures may result in various diseases and symptoms, both respiratory and non-respiratory. Respiratory health complaints are common in damp buildings and have been more thoroughly studied than non-respiratory complaints. Respiratory diseases and symptoms which may be produced by exposure to indoor fungi include asthma development, exacerbation of asthma, hypersensitivity pneumonitis, cough, wheeze, dyspnea (shortness of breath), nasal and throat symptoms, and respiratory infections. In addition to these illnesses, rhinosinusitis and sarcoidosis in water-damaged building occupants are also drawing more scientific attention. In this article, we explore the evidence for adverse effects of fungal exposure on respiratory health in damp indoor environments and potential disease mechanisms related to the exposure.

Predictors of Childhood Allergic Rhinitis

Source: Codispoti C, Levin L, LeMasters G, et al. Breast-feeding, aeroallergen sensitization, and environmental exposures during infancy are determinants of childhood allergic rhinitis. J Allergy Clin Immunol. 2010; 125(5): 1054– 1060; doi: 10.1016/j.jaci.2010.02.004Investigators from Cincinnati Children’s Hospital and the University of Cincinnati sought to evaluate the combined effects of host factors and outdoor and indoor environmental exposures on the development of childhood allergic rhinitis (AR). Participants included a prospective cohort of children born to atopic parents from the greater Cincinnati area and followed annually until age 3 years. Infants were enrolled in the study if either parent had atopy and at least one positive skin prick test (SPT).The families returned for a comprehensive study visit at ages 1 and 3 years. The infants underwent a physical examination and SPT for 15 aeroallergens, egg, and milk. Parents completed a medical history and home environmental questionnaire. Child respiratory symptoms were captured using items adapted from the validated International Study of Asthma and Allergies in Childhood questionnaire. Primary outcome was the presence of AR at age 3 years defined by parental report of no upper respiratory infection symptoms and a positive SPT to one or more aeroallergens. Children with AR were compared to children without symptoms and with a negative SPT.Additional study evaluations included house dust endotoxin (HDE) at 8 months of age, outdoor traffic exposure estimation, elemental carbon counts attributable to traffic, and pollen counts. Additional variables included smoke exposure, breastfeeding duration, household income, dog exposure, and number of children in the home at 1 year of age.At age 3 years, 606 children completed the evaluations and SPT (21.5% African American, 78.6% non-African American). A total of 116 (19%) children had AR and 245 (40%) were nonatopic and asymptomatic. These 361 children comprised the case and comparison groups. Of the remaining children, 151 were atopic and asymptomatic and 94 were nonatopic but symptomatic.Univariate analysis of factors associated with AR at age 3 years included birth during the spring or summer months, a positive SPT to milk, egg, or both, and a positive SPT to any tree pollen in infancy. Prolonged breastfeeding duration (at least four months) was only protective in African American subjects (Adjusted OR=0.8; 95% CI, 0.6–0.9). Development of AR was associated with HDE with concentrations between 36.6 and 244.7 EU/mg. No association with AR was found for elemental carbon attributable to traffic, environmental tobacco smoke exposure, cat allergen levels, number of dogs in the home, fungal spore, or ragweed, tree, or grass pollen counts. Multivariate analysis was similar to the univariate analysis except that more than one child in the home during infancy was found to be protective against AR (Adjusted OR=0.4; 95% CI, 0.2–0.8). The authors conclude that multiple risk factors exist for childhood AR, that SPT is valuable in assessing that risk, and that African American infants are protected by prolonged breastfeeding.The increased prevalence of allergic diseases has stimulated research to identify potential disease-modifying measures. Studies have been inconclusive in identifying effective preventative measures such as avoidance of cat and dog allergens, gradual introduction of solid foods, and avoidance of maternal smoking.The belief that breastfeeding should be recommended for primary prevention of allergic disease is widespread. Exclusive breastfeeding beyond four months of age reduces the development of atopic disease in early life, but the long-term benefits are in question.1 One study has suggested that breastfeeding increases both asthma and allergen sensitization in adult life, but weighing the study’s findings is difficult because the breastfeeding was not always exclusive.2 Another breastfeeding study demonstrated a protective effect on infantile wheezing of breastfeeding in early life but increased asthma incidence in older atopic children.3 There is evidence that food allergies in infancy are a risk factor for the development of both allergic rhinitis and asthma.4Most breastfeeding studies do not take into account additional environmental and host factors in the development of allergic diseases. The current study is the first to suggest that prolonged breastfeeding in African American subjects may have a protective effect on the development of allergic rhinitis. Follow-up studies of this birth cohort to determine what proportion eventually develop asthma or other atopic diseases will be of interest.

Elementary School Indoor Environmental Exposures and Airway Inflammation in Children with Asthma

Elementary School Indoor Environmental Exposures and Airway Inflammation in Children with Asthma

A first French assessment of population exposure to tetrachloroethylene from small dry-cleaning facilities

Used as a solvent in the dry-cleaning industry, tetrachloroethylene (C(2)Cl(4)) can be a pollutant of residential indoor air, which can cause long-term harmful exposures because of its neurotoxicity and probable carcinogenicity. In France, dry-cleaning facilities are integrated in urban environments (shopping malls, residential buildings) and can contribute to C(2)Cl(4) exposure for customers and residents. This exploratory work presents the results from five studies carried out in one shopping mall and four residential buildings housing a dry-cleaning facility. These studies involved dry-cleaning machines fitted with a Carbon Adsorber and unfitted, with or without Air Exhaust System. Samples were collected in the cleaning facilities and in the apartments located above with passive samplers allowing measurement of time-integrated concentrations on a 7 days sampling period. It has obviously shown the degradation of indoor air quality in these environments and underlined the contributing role of the machine technology and ventilation system on the amount of released C(2)Cl(4) in the indoor air. To temper these results, it must be pointed out that some parameters (building insulation, amount of solvent used...) which would influence C(2)Cl(4) fugitive release have not been quantified and should be looked at in further studies. In France, dry-cleaning facilities are frequently integrated in urban environments (large shopping malls or residential buildings) and can significantly contribute to tetrachloroethylene (C(2)Cl(4)) population exposure. The amount of fugitive releases in these environments depends on several parameters such as the dry-cleaning machine technology (fitted or unfitted with a carbon adsorber) and the ventilation (air exhaust system). To reduce C(2)Cl(4) exposure in residential buildings and other indoor environments with on-site dry cleaners, carbon adsorber unequipped machine should be replaced by newer technology and dry cleaners should be equipped with mechanical air exhaust systems.

The influence of chemical interactions at the human surface on breathing zone levels of reactants and products

Using computational fluid dynamics simulations of an occupant in a ventilated room, we find that breathing zone ozone levels can be substantially lower and ozone reaction products associated with human surfaces (ORPHS) levels considerably higher than room levels. For air exchange rates <3/h, the ratio of the breathing zone to the ozone concentration 1 m from the body (bulk air), r(ozone), ranges from 0.59 to 0.75 for floor or ceiling air supply. ORPHS are enriched in the breathing zone, with concentrations for these conditions ranging from 1.2 to 2.5 greater than bulk air concentrations. At high air exchange rates (>8/h), the breathing zone concentrations approach bulk air concentrations (r(ozone) > 0.9) with a floor supply, whereas large concentration gradients occur between breathing zone and bulk air with a ceiling supply. At these high air exchange rates, ORPHS levels are 1.6-2.0 and 2.9-6.0 times the bulk air concentrations for floor and ceiling supply, respectively. The extent of depletion of ozone or enrichment of ORPHS is large enough that reliance on micro-environmental measurements alone, to assess the intake of ozone or ORPHS, is undesirable. Chemical reactions between ozone and human and clothing surfaces are predicted to significantly reduce ozone concentrations, and increase ozone reaction products associated with human surfaces (ORPHS) concentrations, in the breathing zone, relative to those concentrations in the larger microenvironment of a room. Existing measurements may overestimate ozone exposure and intake in typical indoor environments.

What can we learn about asthma and allergy from the follow‐up of the RHINE and the ECRHS studies?

The international population-based studies RHINE and ECRHS have provided new insight in the epidemiology and management of asthma, allergy and rhinitis in young adults. The aim of the present review is to focus on longitudinal results with regard incidence and net change of asthma and asthma-like symptoms, risk factors and management of asthma, with special reference to the Nordic-Baltic countries. Asthma and rhinitis are common conditions that are important in a public health perspective. There are gender differences in incidence and remission. A socio-economic gradient that non-atopic asthma is more strongly related to poverty seems to have developed in the last decade. These findings will challenge our welfare states in the future. In addition, occupational, as well as indoor and outdoor environmental exposures, influenced the onset of asthma. The population-attributable risk for adult asthma because of occupational exposures is equivalent to an incidence of new-onset asthma of 250-300 cases per million per year. Genetic factors, allergic sensitisation, gastro-oesophageal reflux, habitual snoring, diet and other factors may also contribute to the onset of asthma and rhinitis. Even though management of asthma has improved, there are still great variations throughout Europe. These findings highlight the key role doctors and nurses play in educating and reviewing management of patients.

Early environmental determinants of asthma risk in a high‐risk birth cohort

Environmental exposures during early life have been suggested to have the greatest impact on childhood asthma. Our aim was to evaluate the risk factors associated with asthma at age 7 yr in a high-risk cohort that participated in a randomized controlled study on the primary prevention of asthma. Indoor exposures were characterized before birth and at 2 weeks, 4, 8, 12, 18, and 24 months after birth and again at 7 yr. Nasal scrapings for respiratory viruses were done at the same intervals during the first 2 yr. At age 7, the children were assessed by a pediatric allergist and had allergy skin tests. Logistic regression analysis was undertaken to evaluate the effect of exposures on asthma for the entire cohort with adjustment for group allocation. In addition to the lower risk of asthma in the intervention group, we found a higher prevalence of asthma at age 7 for males, those having a positive history of asthma in mother, father, or older siblings, for children residing in Winnipeg and for atopic subjects. Upon adjustment for intervention group assignment and baseline factors, significant environmental risk factors during year 1 included dog ownership and respiratory syncytial viral infection detected at 12 months while maternal smoking was protective. Dog ownership was a significant risk factor in year 2, but highly correlated with dog ownership in year 1. Indoor environmental exposures during year 7 were not associated with asthma at age 7. Maternal smoking at year 7 was associated with a reduced risk of asthma at 7 yr. Early-life exposures were more important determinants than those in later years. A 'window of opportunity' exists for intervention measures to be applied.

Exposure to Mosquito Coil Smoke May be a Risk Factor for Lung Cancer in Taiwan

BackgroundAbout 50% of lung cancer deaths in Taiwan are not related to cigarette smoking. Environmental exposure may play a role in lung cancer risk. Taiwanese households frequently burn mosquito coil at home to repel mosquitoes. The aim of this hospital-based case-control study was to determine whether exposure to mosquito coil smoke is a risk for lung cancer.MethodsQuestionnaires were administered to 147 primary lung cancer patients and 400 potential controls to ascertain demographic data, occupation, lifestyle data, indoor environmental exposures (including habits of cigarette smoking, cooking methods, incense burning at home, and exposure to mosquito coil smoke ), as well as family history of cancer and detailed medical history.ResultsMosquito coil smoke exposure was more frequent in lung cancer patients than controls (38.1% vs.17.8%; p<0.01). Risk of lung cancer was significantly higher in frequent burners of mosquito coils (more than 3 times [days] per week) than nonburners (adjusted odds ratio = 3.78; 95% confidence interval: 1.55-6.90). Those who seldom burned mosquito coils (less than 3 times per week) also had a significantly higher risk of lung cancer (adjusted odds ratio = 2.67; 95% confidence interval: 1.60-4.50).ConclusionExposure to mosquito coil smoke may be a risk factor for development of lung cancer.

A comparison between occupants’ and inspectors’ reports on home dampness and their association with the health of children: The ALLHOME study

There is some discussion concerning the methodology to be used in order to obtain health-relevant information regarding moisture-related problems in homes (dampness). Occupants’ reports, inspectors’ observations and physical measurements are often used methods. In the current study, data on dwelling dampness and characteristics as reported by parents of 216 pre-school children (the cross-sectional questionnaire study ALLHOME-1) was compared with the information collected by non-professional dwelling inspectors in a nested case–control study (the ALLHOME-2 study). The study took place in the cities of Burgas and Sofia in Bulgaria. The inspectors reported less visible mould, but more damp stains and a mouldy odour than the parents. Exposure to dampness, as reported by parents, was significantly associated with airways, nose and/or skin symptoms (case status) among children, while no association was found between inspectors’ observations on dampness and children's health. Parental reports on housing characteristics such as type of house, residential situation, and type of flooring material matched with those identified by the inspectors and therefore can be used as a reliable source of information in studies on indoor environmental exposure and health. With regard to dampness, parental reports seem to be more health relevant than inspectors reports.

Analysis of Fungal Flora in Indoor Dust by Ribosomal DNA Sequence Analysis, Quantitative PCR, and Culture

In recent years increasing attention has been given to the potential health effects of fungal exposure in indoor environments. We used large-scale sequencing of the fungal internal transcribed spacer region (ITS) of nuclear ribosomal DNA to describe the mycoflora of two office buildings over the four seasons. DNA sequencing was complemented by cultivation, ergosterol determination, and quantitative PCR analyses. Sequences of 1,339 clones were clustered into 394 nonredundant fungal operational taxonomical units containing sequences from 18 fungal subclasses. The observed flora differed markedly from that recovered by cultivation, the major differences being the near absence of several typical indoor mold genera such as Penicillium and Aspergillus spp. and a high prevalence of basidiomycetes in clone libraries. A total of 55% of the total diversity constituted of unidentifiable ITS sequences, some of which may represent novel fungal species. Dominant species were Cladosporium cladosporioides and C. herbarum, Cryptococcus victoriae, Leptosphaerulina americana and L. chartarum, Aureobasidium pullulans, Thekopsora areolata, Phaeococcomyces nigricans, Macrophoma sp., and several Malassezia species. Seasonal differences were observed for community composition, with ascomycetous molds and basidiomycetous yeasts predominating in the winter and spring and Agaricomycetidae basidiomycetes predominating in the fall. The comparison of methods suggested that the cloning, cultivation, and quantitative PCR methods complemented each other, generating a more comprehensive picture of fungal flora than any of the methods would give alone. The current restrictions of the methods are discussed.

Biochemical and Molecular Biological Aspects of Silverfish Allergens

Insects and insect-derived materials have been implicated as a risk factor for sensitization and subsequent elicitation of allergic rhinitis and allergic bronchial asthma. During the last decades, insects other than those known as allergenic, were investigated for their potential role in inducing and triggering an IgE immune response. Among these, the silverfish, an insect belonging to the Thysanura order, appeared to be of particular interest. Silverfish (Lepisma saccharina) is the most primitive living insect, and represents a descendent of the ancestral wingless insects. They are 3-12 mm long, have three tail feelers and are covered with shiny scales. They shun light and need a humid environment and their diet consists of carbohydrate materials such as paper and book-binding glue, crumbs of bread and flour. Because of these features, silverfish finds an optimal habitat both in dwellings and workplaces and in spite of its antiquity, silverfish has succeeded in exploiting the new opportunity created by man. Although its importance significantly increased when it has been demonstrated that house dust contains significant silverfish levels even in houses where the inhabitants were unaware of its presence, no silverfish extract for diagnosis of allergic diseases is commercially available yet. Identification of optimal extraction conditions and characterization of allergenic extracts are the first steps to obtain an effective allergen preparation suitable for diagnosis and therapy, and will be useful as a reference preparation for assessing silverfish exposure in different indoor environments. It has been cloned and characterized a silverfish tropomyosin, named Lep s 1, which represents the first allergen identified in silverfish extract and can be regarded as a molecule cross-reactive among inhalant and edible invertebrates allergenic sources. rLep s 1 displayed biological activity, suggesting that it could be regarded as a useful tool to study the role of silverfish tropomyosin in the sensitization to invertebrate allergic sources.