Associations between air pollutants and peak expiratory flow and fractional exhaled nitric oxide in students.

BACKGROUND: Studies on the effects of outdoor air pollution on the respiratory health of students in tropical countries such as Malaysia are limited.OBJECTIVE: To assess associations between outdoor air pollutants and peak expiratory flow (PEF) and fractional exhaled nitric oxide (FeNO).METHOD: PEF and FeNO levels of 487 students recruited in Melaka and Putrajaya, Malaysia, were measured in April and June 2014. Multiple linear regression with mutual adjustment was used to analyse the associations between exposure to air pollution and health.RESULTS: PEF was significantly associated with ozone for 1-day exposure (ß = -13.3 l/min, 95% CI -22.7 to -3.8), carbon monoxide for 2-day exposure (ß = -57.2 l/min, 95% CI -90.7 to -23.7) and particulate matter ≦10 µm in diameter for 3-day exposure (ß = -6.0 l/min, 95% CI -9.2 to -2.8) and 7-day exposure (ß = -8.6 l/min, 95% CI -13.0 to -4.1). Stratified analysis showed that associations between PEF and outdoor air pollutant exposures were similar in students with and without elevated FeNO levels.CONCLUSION: Outdoor air pollution in Malaysia may cause airway obstruction unrelated to eosinophilic airway inflammation among students as measured using FeNO.

Respiratory health among office workers in Malaysia and endotoxin and (1,3)-ß-glucan in office dust.

OBJECTIVE: To examine the associations between endotoxin and (1,3)-ß-glucan concentrations in office dust and respiratory symptoms and airway inflammation among 695 office workers in Malaysia.METHODS: Health data were collected using a questionnaire, sensitisation testing and measurement of fractional exhaled nitric oxide (FeNO). Indoor temperature, relative air humidity (RH) and carbon dioxide (CO2) were measured in the offices and settled dust was vacuumed and analysed for endotoxin and (1,3)-ß-glucan concentrations. Associations were analysed by two level multiple logistic regression.RESULTS: Overall, 9.6% of the workers had doctor-diagnosed asthma, 15.5% had wheeze, 18.4% had daytime attacks of breathlessness and 25.8% had elevated FeNO (≥25 ppb). The median levels in office dust were 11.3 EU/mg endotoxin and 62.9 ng/g (1,3)-ß-glucan. After adjusting for personal and home environment factors, endotoxin concentration in dust was associated with wheeze (P = 0.02) and rhinoconjunctivitis (P = 0.007). The amount of surface dust (P = 0.04) and (1,3)-ß-glucan concentration dust (P = 0.03) were associated with elevated FeNO.CONCLUSION: Endotoxin in office dust could be a risk factor for wheeze and rhinoconjunctivitis among office workers in mechanically ventilated offices in a tropical country. The amount of dust and (1,3)-ß-glucan (a marker of indoor mould exposure) were associated with Th2 driven airway inflammation.

Levels of fractional exhaled nitric oxide in children in relation to air pollution in Chinese day care centres.

OBJECTIVE: To study fractional exhaled nitric oxide (FeNO) levels among pre-school children in day care centres (DCCs) in relation to indoor and outdoor air pollution in northern China. DESIGN: This was a cross-sectional study among children aged 5 years from 34 classrooms at 10 randomly selected DCCs in Taiyuan, China. A total of 507 (99%) children participated. Air pollution and carbon dioxide (CO2) levels were measured in the classroom and outside the school. Linear mixed models were applied for statistical analysis. RESULTS: The geometric mean FeNO was 9.1 ± 1.5 parts per billion; 11.6% of children had wheeze, 6.0% had dry cough, 26.4% rhinitis symptoms, 1.6% ever physician-diagnosed asthma and 29.2% ever physician-diagnosed pneumonia. FeNO levels were associated with current wheeze (P = 0.04) and ever physician-diagnosed pneumonia (P = 0.05). The mean indoor concentrations were particulate matter with a diameter of <2.5 µm (PM2.5) 268 µg/m3, sulfur dioxide (SO2) 40.5 µg/m3, nitrogen dioxide (NO2) 43.0 µg/m3 and CO2 827 parts per million. Outdoor concentrations were PM2.5 244 µg/m3, SO2 106.6 µg/m3 and NO2 40.9 µg/m3. PM2.5 levels inside (P = 0.002) and outside DCCs (P = 0.05) were associated with FeNO levels. CONCLUSION: PM2.5 levels inside and outside DCCs in China can contribute to airway inflammation in pre-school children. Children with current wheeze and ever physician-diagnosed pneumonia may have higher FeNO levels.

Asthma symptoms among Chinese children: the role of ventilation and PM10 exposure at school and home.

SETTING: Respiratory symptoms in relation to environment in Taiyuan, China. OBJECTIVE: To study associations between school/home exposure and prevalence of respiratory symptoms and self-reported respiratory infections (RIs) among students. DESIGN: A total of 2134 pupils from 10 schools answered a questionnaire; air pollution at school was measured. RESULTS: The prevalence of current wheeze, daytime attacks of breathlessness, nocturnal cough, nocturnal respiratory symptoms and RI was respectively 4.4%, 18.7%, 11.6%, 3.6% and 32.3%. Environmental tobacco smoke (ETS) at home was associated with daytime attacks of breathlessness (OR 1.41), nocturnal cough (OR 1.41) and RI (OR 1.26). Redecoration or indoor painting at home was associated with wheeze (OR 2.02), daytime attacks of breathlessness (OR 1.57) and nocturnal symptoms (OR 1.83). Dampness or mould at home was associated with daytime attacks of breathlessness (OR 1.68), nocturnal cough (OR 1.68) and RI (OR 1.69). Particulate matter of diameter  10 microns (PM10) in the classroom was associated with nocturnal cough (OR 1.20/10 µg/m3). PM10 outside school was associated with daytime attacks of breathlessness (OR 1.07/10 µg/m3) and nocturnal cough (OR 1.13/10 µg/m3). Indoor carbon dioxide, a marker of poor ventilation (OR 1.52/1000 parts per million), and relative humidity (RH) (OR 1.33/10%) were associated with nocturnal cough. CONCLUSION: Dampness, redecoration and ETS at home, as well as poor ventilation flow, and high RH and PM10 concentration at school may influence respiratory health.

Patient-reported signs of dampness at home may be a risk factor for chronic rhinosinusitis: A cross-sectional study.

BACKGROUND: An association between dampness at home and respiratory conditions has been convincingly demonstrated in children. Fewer studies have been performed in adults, and data are lacking for chronic rhinosinusitis (CRS). With a prevalence of 10.9% in Europe, CRS imposes a significant burden on quality of life, as well as economy. OBJECTIVE: Our aim was to study CRS and other respiratory conditions in relation to dampness at home in a representative sample of adults. METHODS: The Swedish GA2 LEN questionnaire was answered by 26 577 adults (16-75 years) and included questions on respiratory symptoms, smoking, education and environmental exposure. CRS was defined according to the EP3 OS criteria. Dampness was defined as reporting water damage, floor dampness or visible moulds in the home during the last 12 months. The dampness score was ranked from 0 to 3, counting the number of signs of dampness reported. RESULTS: Dampness at home was reported by 11.3% and was independently related to respiratory conditions after adjustment for demographic and socio-economic factors and smoking: CRS odds ratio (OR) 1.71; allergic rhinitis OR 1.24; current asthma OR 1.21; wheeze OR 1.37; nocturnal dyspnoea OR 1.80; nocturnal coughing OR 1.34; and chronic bronchitis OR 1.64. The risk of CRS and most of the other respiratory conditions was further elevated in subjects reporting multiple signs of dampness. CONCLUSIONS AND CLINICAL RELEVANCE: This study demonstrated an independent association between dampness at home and CRS in adults. The high burden of this and the other respiratory conditions studied is a strong argument in favour of countering indoor dampness by improving building standards.

Clinical markers of asthma and IgE assessed in parents before conception predict asthma and hayfever in the offspring.

BACKGROUND: Mice models suggest epigenetic inheritance induced by parental allergic disease activity. However, we know little of how parental disease activity before conception influences offspring's asthma and allergy in humans. OBJECTIVE: We aimed to assess the associations of parental asthma severity, bronchial hyperresponsiveness (BHR), and total and specific IgEs, measured before conception vs. after birth, with offspring asthma and hayfever. METHODS: The study included 4293 participants (mean age 34, 47% men) from the European Community Respiratory Health Survey (ECRHS) with information on asthma symptom severity, BHR, total and specific IgEs from 1991 to 1993, and data on 9100 offspring born 1972-2012. Adjusted relative risk ratios (aRRR) for associations of parental clinical outcome with offspring allergic disease were estimated with multinomial logistic regressions. RESULTS: Offspring asthma with hayfever was more strongly associated with parental BHR and specific IgE measured before conception than after birth [BHR: aRRR = 2.96 (95% CI: 1.92, 4.57) and 1.40 (1.03, 1.91), respectively; specific IgEs: 3.08 (2.13, 4.45) and 1.83 (1.45, 2.31), respectively]. This was confirmed in a sensitivity analysis of a subgroup of offspring aged 11-22 years with information on parental disease activity both before and after birth. CONCLUSION & CLINICAL RELEVANCE: Parental BHR and specific IgE were associated with offspring asthma and hayfever, with the strongest associations observed with clinical assessment before conception as compared to after birth of the child. If the hypothesis is confirmed in other studies, parental disease activity assessed before conception may prove useful for identifying children at risk for developing asthma with hayfever.

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

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

Exacerbation of asthma among adults in relation to the home environment in multi-family buildings in Sweden.

OBJECTIVE: To study the association between the home environment and asthma medication and exacerbation of asthma among adults with physician-diagnosed asthma. METHODS: Adults aged 18 years in a stratified sample of multi-family buildings throughout Sweden were invited to respond to a postal questionnaire (the BETSI Study). A total of 639 adults (11.5%) with physician-diagnosed asthma were included. RESULTS: Of the 639 adults, 62.0% were females, 10.8% were current smokers, 62.6% had pollen or furry pet allergy, 61.7% were on current asthma medication and 48.6% had experienced an asthma exacerbation in the past year. Logistic regression models were applied to study the association between the home environment and asthma medication and asthma exacerbation, adjusting for sex, age and smoking status. Asthma medication was more commonly prescribed for those who kept dogs as pets (OR 2.66, 95%CI 1.05-6.75) and in homes with mouldy odour (OR 5.72, 95%CI 1.29-25.4). Asthma exacerbation was more frequent among those living in buildings constructed in 1961-1975 (OR 2.56, 95%CI 1.22-5.34), in areas with a high population density (OR 4.69, 95%CI 1.42-15.5), in rented apartments (OR 1.77, 95%CI 1.12-2.78) and in homes with a greater degree of window opening (OR 1.47, 95%CI 1.12-1.94). CONCLUSIONS: Factors in the home environment were associated with exacerbation of asthma in adults. Certain construction periods (1961-1975), rented apartments, mould, having dogs as pets and living in urban areas were associated with asthma exacerbations.

Current wheeze, asthma, respiratory infections, and rhinitis among adults in relation to inspection data and indoor measurements in single-family houses in Sweden-The BETSI study.

In the Swedish Building Energy, Technical Status and Indoor environment study, a total of 1160 adults from 605 single-family houses answered a questionnaire on respiratory health. Building inspectors investigated the homes and measured temperature, air humidity, air exchange rate, and wood moisture content (in attic and crawl space). Moisture load was calculated as the difference between indoor and outdoor absolute humidity. Totally, 7.3% were smokers, 8.7% had doctor' diagnosed asthma, 11.2% current wheeze, and 9.5% current asthma symptoms. Totally, 50.3% had respiratory infections and 26.0% rhinitis. The mean air exchange rate was 0.36/h, and the mean moisture load 1.70 g/m3 . Damp foundation (OR=1.79, 95% CI 1.16-2.78) was positively associated while floor constructions with crawl space (OR=0.49, 95% CI 0.29-0.84) was negatively associated with wheeze. Concrete slabs with overlying insulation (OR=2.21, 95% CI 1.24-3.92) and brick façade (OR=1.71, 95% CI 1.07-2.73) were associated with rhinitis. Moisture load was associated with respiratory infections (OR=1.21 per 1 g/m3 , 95% CI 1.04-1.40) and rhinitis (OR=1.36 per 1 g/m3 , 95% CI 1.02-1.83). Air exchange rate was associated with current asthma symptoms (OR=0.85 per 0.1/h, 95% CI 0.73-0.99). Living in homes with damp foundation, concrete slabs with overlying insulation, brick façade, low ventilation flow, and high moisture load are risk factors for asthma, rhinitis, and respiratory infections.

The effects of growing up on a farm on adult lung function and allergic phenotypes: an international population-based study.

RATIONALE: Evidence has suggested that exposure to environmental or microbial biodiversity in early life may impact subsequent lung function and allergic disease risk. OBJECTIVES: To investigate the influence of childhood living environment and biodiversity indicators on atopy, asthma and lung function in adulthood. METHODS AND MEASUREMENTS: The European Community Respiratory Health Survey II investigated ∼10 201 participants aged 26-54 years from 14 countries, including participants' place of upbringing (farm, rural environment or inner city) before age 5 years. A 'biodiversity score' was created based on childhood exposure to cats, dogs, day care, bedroom sharing and older siblings. Associations with lung function, bronchial hyper-responsiveness (BHR), allergic sensitisation, asthma and rhinitis were analysed. MAIN RESULTS: As compared with a city upbringing, those with early-life farm exposure had less atopic sensitisation (adjusted OR 0.46, 95% CI 0.37 to 0.58), atopic BHR (0.54 (0.35 to 0.83)), atopic asthma (0.47 (0.28 to 0.81)) and atopic rhinitis (0.43 (0.32 to 0.57)), but not non-atopic outcomes. Less pronounced protective effects were observed for rural environment exposures. Women with a farm upbringing had higher FEV1 (adjusted difference 110 mL (64 to 157)), independent of sensitisation and asthma. In an inner city environment, a higher biodiversity score was related to less allergic sensitisation. CONCLUSIONS: This is the first study to report beneficial effects of growing up on a farm on adult FEV1. Our study confirmed the beneficial effects of early farm life on sensitisation, asthma and rhinitis, and found a similar association for BHR. In persons with an urban upbringing, a higher biodiversity score predicted less allergic sensitisation, but to a lesser magnitude than a childhood farm environment.

The risk of respiratory symptoms on allergen exposure increases with increasing specific IgE levels.

BACKGROUND: The relation between IgE sensitization and allergic respiratory symptoms has usually been evaluated by dichotomizing specific IgE levels. The aim of this study was to evaluate the association between specific IgE levels and risk of symptoms on allergen-related exposure, with special reference to allergen-related asthma-rhinitis comorbidity. METHODS: We considered 6391 subjects enrolled within the European Community Respiratory Health Survey 2, having information on cat/grass/D. pteronyssinus IgE levels and symptoms on exposure to animals/pollen/dust. The risk of oculonasal/asthmalike/both symptoms was evaluated by a multinomial logistic model. RESULTS: A clear positive association was observed between specific IgE levels to cat/grass/mite and the risk of symptoms on each allergen-related exposure (test for trend with P < 0.001). This trend was particularly pronounced when considering the coexistence of asthmalike and oculonasal symptoms. Compared to non-sensitized subjects, subjects with specific IgE to cat >= 3.5 kU/l presented relative risk ratios of 11.4 (95% CI 6.7-19.2), 18.8 (8.2-42.8), and 55.3 (30.5-100.2) when considering, respectively, only oculonasal symptoms, only asthmalike symptoms, or both. A similar pattern was observed when considering specific IgE to grass/mite and symptoms on exposure to pollen/dust. Also the proportion of people using inhaled medicines or visiting a general practitioner for breathing problems in the previous year increased with increasing sum of specific IgE to cat/grass/mite. CONCLUSION: Specific IgE level is the most important predictor of allergen-related symptoms. The risk of both oculonasal/asthmalike symptoms increases with specific IgE levels, suggesting that specific IgE contributes to the 'united airways disease'.

House dust-mite allergen exposure is associated with serum specific IgE but not with respiratory outcomes.

Exposure to house dust has been associated with asthma in adults, and this is commonly interpreted as a direct immunologic response to dust-mite allergens in those who are IgE sensitized to house dust-mite. Mattress house dust-mite concentrations were measured in a population-based sample of 2890 adults aged between 27 and 56 years living in 22 centers in 10 countries. Generalized linear mixed models were employed to explore the association of respiratory symptoms with house dust-mite concentrations, adjusting for individual and household confounders. There was no overall association of respiratory outcomes with measured house dust-mite concentrations, even in those who reported they had symptoms on exposure to dust and those who had physician-diagnosed asthma. However, there was a positive association of high serum specific IgE levels to HDM (>3.5 kUA /l) with mattress house dust-mite concentrations and a negative association of sensitization to cat with increasing house dust-mite concentrations. In conclusion, there was no evidence that respiratory symptoms in adults were associated with exposure to house dust-mite allergen in the mattress, but an association of house mite with strong sensitization was observed.

Subjective health complaints and psychosocial work environment among university personnel.

BACKGROUND: Questionnaires are often used to study health problems in working populations. An association between self-reported symptoms and psychosocial strain has been suggested, but results from such studies are difficult to interpret, as a gender difference might be present. The knowledge in this area is not clear. AIMS: To compare the prevalence of subjective health symptoms and their relation to psychosocial work strain among men and women in different age groups, all working as university staff. METHODS: A cross-sectional survey was carried out among university personnel. The questionnaire included a subjective health complaint inventory consisting of 29 items about subjective somatic and psychological symptoms experienced during the last 30 days and psychosocial work factors. Regression analyses were performed. RESULTS: In total, 172 (86%) of 201 eligible employees participated. Women had a higher prevalence of musculoskeletal symptoms than men. Significant differences were found between the genders for headaches, neck pain and arm pain. There was a significant relationship between musculoskeletal symptoms and work strain for both genders. This was found for both men and women below 40 years and among men above the age of 40. No significant difference was found between genders regarding pseudoneurological, gastrointestinal, allergic and flu-like symptoms. CONCLUSIONS: More female than male university personnel reported musculoskeletal symptoms. The musculoskeletal symptoms were associated with high work strain in both genders, but, for women, this was limited to employees under the age of 40. The cause of this gender difference is unknown.

Acute effects of exposure to vapors of 3-methyl-1-butanol in humans.

UNLABELLED: The secondary alcohol 3-methyl-1-butanol (3MB, isoamyl alcohol) is used, for example, as a solvent in a variety of applications and as a fragrance ingredient. It is also one of the microbial volatile organic compounds (MVOCs) found in indoor air. There are little data on acute effects. The aim of the study was to assess the acute effects of 3MB in humans. Thirty healthy volunteers (16 men and 14 women) were exposed in random order to 1 mg/m(3) 3MB or clean air for 2 h at controlled conditions. Ratings with visual analogue scales revealed slightly increased perceptions of eye irritation (P = 0.048, Wilcoxon) and smell (P < 0.0001) compared with control exposure. The other ratings were not significantly affected (irritation in nose and throat, dyspnea, headache, fatigue, dizziness, nausea, and intoxication). No significant exposure-related effects were found in blinking frequency, tear film break-up time, vital staining of the eye, nasal lavage biomarkers, lung function, and nasal swelling. In conclusion, this study suggests that 3MB is not a causative factor for health effects in damp and moldy buildings. PRACTICAL IMPLICATIONS: 3-Methyl-1-butanol (3MB) is one of the most commonly reported MVOCs in damp and moldy buildings and in occupational settings related to agriculture and composting. Our study revealed no irritation effects at 1 mg/m3, a concentration higher than typically found in damp and moldy buildings. Our study thus suggests that 3MB is not a causative factor for health effects in damp and moldy buildings.

Adverse respiratory effects of outdoor air pollution in the elderly.

Compared to the rest of the population, the elderly are potentially highly susceptible to the effects of outdoor air pollution due to normal and pathological ageing. The purpose of the present review was to gather data on the effects on respiratory health of outdoor air pollution in the elderly, on whom data are scarce. These show statistically significant short-term and chronic adverse effects of various outdoor air pollutants on cardiopulmonary morbidity and mortality in the elderly. When exposed to air pollution, the elderly experience more hospital admissions for asthma and chronic obstructive pulmonary disease (COPD) and higher COPD mortality than others. Previous studies also indicate that research on the health effects of air pollution in the elderly has been affected by methodological problems in terms of exposure and health effect assessments. Few pollutants have been considered, and exposure assessment has been based mostly on background air pollution and more rarely on objective measurements and modelling. Significant progress needs to be made through the development of 'hybrid' models utilising the strengths of information on exposure in various environments to several air pollutants, coupled with daily activity exposure patterns. Investigations of chronic effects of air pollution and of multi-pollutant mixtures are needed to better understand the role of air pollution in the elderly. Lastly, smoking, occupation, comorbidities, treatment and the neighbourhood context should be considered as confounders or modifiers of such a role. In this context, the underlying biological, physiological and toxicological mechanisms need to be explored to better understand the phenomenon through a multidisciplinary approach.

Onset of mucosal, dermal, and general symptoms in relation to biomarkers and exposures in the dwelling: a cohort study from 1992 to 2002.

UNLABELLED: We examined the associations between biomarkers of allergy and inflammation, indoor environment in dwellings, and incidence and remission of symptoms included in the sick building syndrome (SBS) and changes in the home environment of 452 adults who were followed from 1992 to 2002 within the Uppsala part of the European Community Respiratory Health Survey (ECRHS). The 10-year incidence (onset) of general, mucosal, and dermal symptoms was 8.5%, 12.7%, and 6.8%, respectively. Dampness or indoor molds at baseline was a predictor of incidence of general (relative risk [RR] = 1.98), mucosal (RR = 2.28), and dermal symptoms (RR = 1.91). Women had higher incidence of general (RR = 1.74) and mucosal symptoms (RR = 1.71). Indoor painting increased the incidence of general symptoms (RR = 1.62). Bronchial responsiveness (BR), eosinophil counts in blood, total IgE and eosinophilic cationic protein (ECP) in serum at baseline were predictors of incidence of SBS. At follow-up, BR, total IgE, and C-reactive protein (CRP ) were associated with increased incidence of SBS. Moreover, subjects with doctor-diagnosed asthma at baseline had a higher incidence of general (RR = 1.65) and mucosal symptoms (RR = 1.97). In conclusion, female gender, dampness or indoor molds, indoor painting, and biomarkers of allergy and inflammation were associated with a higher incidence of SBS symptoms, in particular mucosal symptoms. PRACTICAL IMPLICATIONS: The focus in Sweden on indoor environment issues over the last few decades has resulted in improvements in dwellings, and reduced tobacco smoking, which could be beneficial for public health. Reducing dampness and molds in the dwelling place is another important way of reducing occurrence of SBS symptoms in the general adult population. The association between the incidence of SBS symptoms and clinical biomarkers of allergy and inflammation suggests a common etiology between inflammatory diseases, including asthma, rhinitis, and SBS. Lastly, good agreement between self-reported and clinically diagnosed atopy indicates that questionnaire data on atopy can be used in epidemiological studies.

Geographical variation and the determinants of domestic endotoxin levels in mattress dust in Europe.

UNLABELLED: Endotoxin exposures have manifold effects on human health. The geographical variation and determinants of domestic endotoxin levels in Europe have not yet been extensively described. To investigate the geographical variation and determinants of domestic endotoxin concentrations in mattress dust in Europe using data collected in the European Community Respiratory Health Survey follow-up (ECRHS II). Endotoxin levels were measured in mattress dust from 974 ECRHS II participants from 22 study centers using an immunoassay. Information on demographic, lifestyle, and housing characteristics of the participants was obtained in face-to-face interviews. The median endotoxin concentration in mattress dust ranged from 772 endotoxin units per gram (EU/g) dust in Reykjavik, Iceland, to 4806 EU/g in Turin, Italy. High average outdoor summer temperature of study center, cat or dog keeping, a high household crowding index, and visible damp patches in the bedroom were significantly associated with a higher endotoxin concentrations in mattress dust. There is a large variability in domestic endotoxin levels across Europe. Average outdoor summer temperature of study center, which explains only 10% of the variation in domestic endotoxin level by center, is the strongest meteorological determinant. The observed variation needs to be taken into account when evaluating the health effects of endotoxin exposures in international contexts. PRACTICAL IMPLICATIONS: The incoherent observations of the health effects of endotoxin may be partly owing to the geographical heterogeneity of endotoxin exposure. Therefore, the observed variation should be considered in further studies. Measurements of indoor endotoxin are recommended as an indicator for the level of exposures of individual domestic environments.

Respiratory health and endotoxin: associations and modification by CD14/-260 genotype.

Exposure to endotoxin has been associated with increased respiratory symptoms and decrements in lung function in occupational settings but little is known about the health effects of domestic exposure in adults. Here, we describe the association of respiratory disease, immunoglobulin (Ig)E sensitisation, bronchial reactivity and lung function with mattress endotoxin levels in adults, and determine whether these associations are modified by polymorphisms in CD14. Endotoxin levels in mattress dust from a population-based sample of 972 adults were measured. Associations were examined using generalised linear mixed models, adjusting for individual and household confounders. Effect modification of these associations by CD14/-260 (rs2569190) was assessed. Mattress endotoxin levels varied from 0.1 to 402.6 EU · mg(-1). Although there was no overall association of lung function with endotoxin exposure, there was evidence that the association of forced expiratory volume in 1 s and forced vital capacity with endotoxin was modified by CD14/-260 genotype (p-value for interaction 0.005 and 0.013, respectively). There was no evidence that symptoms, IgE sensitisation or bronchial reactivity were associated with mattress endotoxin levels. In this large epidemiological study of adults, there was no evidence that mattress endotoxin level was associated with respiratory symptoms or IgE sensitisation but the association of lung function with endotoxin levels may be modified by CD14 genotype.

The prevalence and incidence of sick building syndrome in Chinese pupils in relation to the school environment: a two-year follow-up study.

UNLABELLED: There are few incidence studies on sick building syndrome (SBS). We studied two-year change of SBS in Chinese pupils in relation to parental asthma/allergy (heredity), own atopy, classroom temperature, relative humidity (RH), absolute humidity (AH), crowdedness, CO2, NO2, and SO2. A total of 1993 participated at baseline, and 1143 stayed in the same classrooms after two years. The prevalence of mucosal and general symptoms was 33% and 28% at baseline and increased during follow-up (P < 0.001). Twenty-seven percent reported at least one symptom improved when away from school. Heredity and own atopy were predictors of SBS at baseline and incidence of SBS. At baseline, SO2 was associated with general symptoms (OR=1.10 per 100 µg/m³), mucosal symptoms (OR=1.12 per 100 µg/m³), and skin symptoms (OR=1.16 per 100 µg/m³). NO2 was associated with mucosal symptoms (OR=1.13 per 10 µg/m³), and symptoms improved when away from school (OR=1.13 per 10 µg/m³). Temperature, RH, AH, and CO2 were negatively associated with prevalence of SBS. Incidence or remission of SBS was not related to any exposure, except a negative association between SO2 and new skin symptoms. In conclusion, heredity and atopy are related to incidence and prevalence of SBS, but the role of the measured exposures for SBS is more unclear. PRACTICAL IMPLICATIONS: We found high levels of CO2 indicating inadequate ventilation and high levels of SO2 and NO2, both indoors and outdoors. All schools had natural ventilation, only. Relying on window opening as a tool for ventilation in China is difficult because increased ventilation will decrease the level of CO2 but increase the level of NO2 and SO2 indoors. Prevalence studies of sick building syndrome (SBS) might not be conclusive for causal relationships, and more longitudinal studies on SBS are needed both in China and other parts of the world. The concept of mechanical ventilation and air filtration should be introduced in the schools, and when planning new schools, locations close to heavily trafficked roads should be avoided.