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.

Multifunctional PLGA/Parylene C Coating for Implant Materials: An Integral Approach for Biointerface Optimization.

Functionalizing implant surfaces is critical for improving their performance. An integrated approach was employed to develop a multifunctional implant coating based on oxygen plasma-modified parylene C and drug-loaded, biodegradable poly(dl-lactide-co-glycolide) (PLGA). The key functional attributes of the coating (i.e., anti-corrosion, biocompatible, anti-infection, and therapeutic) were thoroughly characterized at each fabrication step by spectroscopic, microscopic, and biologic methods and at different scales, ranging from molecular, through the nano- and microscales to the macroscopic scale. The chemistry of each layer was demonstrated separately, and their mutual affinity was shown to be indispensable for the development of versatile coatings for implant applications.

Microbiological investigations of oxygen plasma treated parylene C surfaces for metal implant coating.

Parylene C surface was modified by the use of oxygen plasma treatment and characterized by microscopic and surface-sensitive techniques (E-SEM, AFM, XPS, LDI-TOF-MS, contact angle). The influence of the treatment on surface properties was investigated by calculations of surface free energy (Owens-Wendt method). Moreover, early adhesion (Culture Plate Method, Optical Microscopy Test) and biofilm formation ability (Cristal Violet Assay) on the parylene C surface was investigated. The bacteria strains which are common causative agents of medical device-associated infections (Staphylococcus aureus, Staphylococcus epidermidis and Pseudomonas aeruginosa--reference strains and clinical isolates) were used. It was concluded that chemical (oxygen insertion) and physical (nanotopography generation) changes, have a significant impact on the biocompatibility in terms of increased hydrophilicity (θ w of unmodified sample = 88° ± 2°, θ w of 60 min modified sample = 17.6° ± 0.8°) and surface free energy (SFE of unmodified sample = 42.4 mJ/m(2), and for 60 min modified sample = 70.1 mJ/m(2)). At the same time, no statistical effect on biofilm production and bacteria attachment to the modified surface of any of the tested strains was observed.

Oxygen plasma functionalization of parylene C coating for implants surface: nanotopography and active sites for drug anchoring.

The effect of oxygen plasma treatment (t=0.1-60 min, pO2=0.2 mbar, P=50 W) of parylene C implant surface coating was investigated in order to check its influence on morphology (SEM, AFM observations), chemical composition (XPS analysis), hydrophilicity (contact angle measurements) and biocompatibility (MG-63 cell line and Staphylococcus aureus 24167 DSM adhesion screening). The modification procedure leads to oxygen insertion (up to 20 at.%) into the polymer matrix and together with surface topography changes has a dramatic impact on wettability (change of contact angle from θ=78±2 to θ=33±1.9 for unmodified and 60 min treated sample, respectively). As a result, the hydrophilic surface of modified parylene C promotes MG-63 cells growth and at the same time does not influence S. aureus adhesion. The obtained results clearly show that the plasma treatment of parylene C surface provides suitable polar groups (C=O, C-O, O-C=O, C-O-O and O-C(O)-O) for further development of the coating functionality.

Sick building syndrome and perceived indoor environment in relation to energy saving by reduced ventilation flow during heating season: a 1 year intervention study in dwellings.

UNLABELLED: Ventilation in Scandinavian buildings is commonly performed by means of a constant flow ventilation fan. By using a regulated fan, it is possible to make a seasonal adjustment of outdoor ventilation flow. Energy saving can be achieved by reducing the mechanical ventilation flow during the heating season, when natural ventilation driven by temperature differences between outdoor and indoor is relatively high. This ventilation principle has been called 'seasonally adapted ventilation (SAV)'. The aim was to study if a 25-30% reduction of outdoor ventilation flow during heating season influenced sick building syndrome (SBS) and the perception of the indoor environment. This was done in a 1-year cross-over intervention study in 44 subjects in a multi-family building. During the first heating season (November to April), one part of the building (A) got a reduced flow during the heating season [0.4-0.5 air exchanges per hour (ACH)] while the other part (B) had constant flow (0.5-0.8 ACH). The next heating season, part A got constant flow, while part B got reduced ventilation flow. Reduced ventilation increased the relative air humidity by 1-3% in the living room (mean 30-37% RH), 1-5% in the bathroom (mean 48-58% RH) during heating season. The room temperature increased 0.1-0.3 degrees C (mean 20.7-21.6 degrees C), mean carbon dioxide (CO2) concentration in the bedroom increased from 920 to 980 p.p.m. at reduced flow. The indoor air quality was perceived as poorer at reduced outdoor airflow, both in the bedroom and in the apartment as a whole. There was a significant increase of stuffy odor (P = 0.05) at reduced outdoor airflow and the indoor air quality was perceived as poorer, both in the bedroom (P = 0.03) and in the apartment as a whole (P = 0.04). No significant influence on SBS symptoms or specific perceptions such as odors, draught, temperature, air dryness or stuffy air could be detected. In conclusion, reducing the ventilation flow in dwellings to a level below the current Swedish ventilation standard (0.5 ACH) may cause a perception of impaired air quality. Technical measurements could only demonstrate a minor increase of indoor temperature, relative air humidity, and bedroom CO2 concentration. This illustrates that it is important to combine technical measurements with a longitudinal evaluation of occupant reactions, when evaluating energy-saving measures. PRACTICAL IMPLICATIONS: It is important to combine technical measurements with a longitudinal evaluation of occupant reactions, when evaluating energy-saving measures. Reduction of outdoor airflow in dwellings below the current ventilation standard of 0.5 ACH may lead to a perception of impaired air quality, despite only a minor increase of bedroom CO2-concentration.

The Stockholm Indoor Environment Questionnaire: a sociologically based tool for the assessment of indoor environment and health in dwellings.

The aim was to develop and validate a standardized questionnaire - the Stockholm Indoor Environment Questionnaire (SIEQ). The validation procedure was based on sociological principles and test procedures for validation. The indicators of indoor environment are air quality, thermal climate, noise, and illumination. The indicators of health are symptoms comprised in the sick building syndrome (SBS). The questionnaire also contains questions about the apartment, individual behavior, and personal factors. The everyday language describing the building and its function was first obtained by qualitative personal interviews, then by standardized questions. The interview questionnaire was transformed into a postal self-administered questionnaire. The reduction of the questionnaire was based on correlation analysis. It was found that to obtain a good validity, general questions are not sufficient, but specific question on perceptions and observations are needed. Good test-retest agreement was found both on an area level, building level, and individually. For each indicator, a set of questions are constructed and validated. SIEQ has been used in several studies, and the results are presented in graphic problem profiles. Reference data has been calculated for the Stockholm area.

Ocular, nasal, dermal and respiratory symptoms in relation to heating, ventilation, energy conservation, and reconstruction of older multi-family houses.

The aim was to study relationships between symptoms compatible with the sick building syndrome, type of heating and ventilation system, energy saving, and reconstruction in older dwellings. In Stockholm, 4815 inhabitants in 231 multi-family buildings built before 1961 were randomly selected, of whom 3241 participated (77%). Symptoms and personal factors were assessed by a postal questionnaire. Independent information on building characteristics, and energy saving measures was gathered from the building owners. Multiple logistic regression analysis was applied to calculate odds ratios (OR) adjusting for age, gender, hay fever, current smoking, population density, type of ventilation, type of heating system, and ownership of the building. Subjects in buildings with a mechanical ventilation system had less ocular and nasal symptoms (OR = 0.29-0.85). Heating by electric radiators, and wood heating was associated with an increase of most symptoms (OR = 1.18-1.74). In total, 48% lived in buildings that had gone through at least one type of reconstruction or energy saving remedies during the latest 10 years, including exchange of heating or ventilation system, and sealing measures (exchange of windows, sealing of window frames, roof/attic insulation, and phasade insulation). Energy saving was associated with both a decrease and increase of different symptoms. Major reconstruction of the interior of the building was associated with an increase of most symptoms (OR = 1.09-1.90), and buildings with more than one sealing measure had an increase of ocular, nasal symptoms, headache and tiredness (OR = 1.22-2.49). In conclusion, major reconstruction of the interior, direct heated electric radiators, wood heating, and multiple sealing of buildings were associated with an increase of some symptoms. The study supports the view that mechanical ventilation in dwellings is beneficial from a health point of view.

Sick building syndrome in relation to building dampness in multi-family residential buildings in Stockholm.

OBJECTIVES: The aim was to study relationships between symptoms compatible with sick building syndrome (SBS) on one hand, and different indicators of building dampness in Swedish multi-family buildings on the other. METHODS: In Stockholm, 609 multi-family buildings with 14,235 dwellings were identified, and selected by stratified random sampling. The response rate was 77%. Information on weekly symptoms, age, gender, population density in the apartment, water leakage during the past 5 years, mouldy odour, condensation on windows, and high air humidity in the bathroom was assessed by a postal questionnaire. In addition, independent information on building characteristics was gathered from the building owners, and the central building register in Stockholm. Multiple logistic regression analysis was applied, and adjusted odds ratios (OR) were calculated, adjusted for age and gender, population density, and selected building characteristics. RESULTS: Condensation on windows, high air humidity in the bathroom, mouldy odour, and water leakage was reported from 9.0%, 12.4%, 7.7% and 12.7% of the dwellings, respectively. In total 28.5% reported at least one sign of dampness. All indicators of dampness were related to an increase of all types of symptoms, significant even when adjusted for age, gender, population density, type of ventilation system, and ownership of the building. A combination of mouldy odour and signs of high air humidity was related to an increased occurrence of all types of symptoms (OR = 3.7-6.0). Similar findings were observed for a combination of mouldy odour and structural building dampness (water leakage) (OR = 2.9 5.2). In addition, a dose-response relationship between symptoms and number of signs of dampness was observed. In dwellings with all four dampness indicators, OR was 6.5, 7.1, 19.9, 5.8, 6.1, 9.4, 15.0 for ocular, nasal, throat, dermal symptoms, cough, headache and tiredness, respectively. CONCLUSION: Signs of high air humidity, as well as of structural building dampness, are common in multi-family buildings in Stockholm. Reports of building dampness in dwellings is related to a pronounced increase of symptoms compatible with the SBS, even when adjusted for possible confounding by age, gender, population density, and building-related risk factors.

Asthma symptoms in relation to building dampness and odour in older multifamily houses in Stockholm.

SETTING: Respiratory symptoms and hay fever in adults in relation to the indoor environment. OBJECTIVES: To study relationships between reports on respiratory symptoms and hay fever and building dampness and odours in older multifamily dwellings. DESIGN: A questionnaire study in a random sample of 231 multifamily buildings built before 1961, which included 4224 apartments. The response rate was 77% (n = 3241). Information on building characteristics was gathered from building owners and the central building register in Stockholm. Multiple logistic regression analysis was applied, adjusting for age, sex, current smoking, population density, type of ventilation and ownership. RESULTS: In total, 22% reported at least one sign of dampness, and 32% reported odour in the dwelling. All types of odours were more common in damp buildings. Reports on dampness and odours were related to asthma symptoms and current cough, even when adjusting for potential confounders. A combination of odour and signs of high air humidity was related to an increase in asthma symptoms (OR = 2.82; 95%CI 2.70-2.95) and current cough (OR = 5.29; 95%CI 4.99-5.62). Similar findings were observed for a combination of odour and history of water leakage in the last 5 years, with an increase in asthma symptoms (OR = 3.59; 95%CI 3.37-3.82) and current cough (OR = 2.86; 95%CI 2.61-3.14). There was a dose-response relationship between respiratory symptoms and the number of signs of dampness. An association was also observed between dampness and a history of pollen allergy. CONCLUSIONS: Signs of high indoor air humidity, water leakage and odours were common, and related to respiratory symptoms. Exposure to odorous compounds from building dampness may be significant with respect to respiratory symptoms and possibly atopic sensitisation.

Development of a multiple regression model to identify multi-family residential buildings with a high prevalence of sick building syndrome (SBS).

The aim was to develop a multiple logistic regression model to identify multi-family houses with an increase of sick building syndrome (SBS). In Stockholm, 609 multi-family buildings with 14,235 dwellings were selected by stratified random sampling. The response rate was 77%. Multiple logistic regression analysis was applied, adjusting for ownership of the building, building age and size, age, gender, and atopy. Females, subjects with allergy, those above 65 yr, and those in new buildings reported significantly more SBS. Subjects owning their own building reported less SBS, but the relationship between ownership and building age was strong. A regression model, including factors with a high explanatory value was developed. According to the model, 5% of all buildings built before 1961, 13% of those built 1976-1984, and 15% of those built 1985-1990 would have significantly more SBS than expected. In conclusion, SBS is related to personal factors, building age, and ownership of the building. To identify multi-family buildings with more SBS than expected, it is necessary to adjust for ownership and population characteristics.