PubMed Health⌕ Search

Biomedical subjects

B Brunekreef

Publications and source records attributed to B Brunekreef.

At least 127 records · Page 7Linked to original sources
PubMed1997

Childhood exposure to PM10: relation between personal, classroom, and outdoor concentrations.

OBJECTIVES: To investigate the validity of outdoor concentrations of particulate matter < 10 microns diameter (PM10) as a measure of exposure in time series studies, and to study the extent to which differences between personal and outdoor PM10 concentrations can be explained. METHODS: Four to eight repeated measurements of personal and outdoor PM10 concentrations were conducted for 45 children, aged 10-12 years, from four schools in Wageningen and Amsterdam, The Netherlands. Repeated PM10 measurements in the classrooms were conducted in three of the schools. Averaging time was 24 hours for the personal and outdoor measurements, and eight hours (daytime) and 24 hours for the classroom measurements. For each child separately, personal exposures were related to outdoor concentrations in a regression analysis. The distribution of the individual correlation and regression coefficients was investigated. Information about factors that might influence personal exposures was obtained by questionnaire. RESULTS: Median Pearson's correlations between personal and outdoor concentrations were 0.63 for children with parents who did not smoke and 0.59 for children with parents who smoked. For children with parents who did not smoke, excluding days with exposure to environmental tobacco smoke (ETS) improved the correlation to a median R of 0.73. The mean personal PM10 concentration was 105 micrograms/m3; on average 67 micrograms/m3 higher than the corresponding outdoor concentrations. The main part of this difference could be attributed to exposure to ETS, to high PM10 concentrations in the classrooms, and to (indoor) physical activity. CONCLUSIONS: The results show a reasonably high correlation between repeated personal and outdoor PM10 measurements within children, providing support for the use of fixed site measurements as a measure of exposure to PM10 in epidemiological time series studies. The large differences between personal and outdoor PM10 concentrations probably result from a child's proximity to particle generating sources and particles resuspended by personal activities.

Air Pollutants↗
PubMed1997

Acute effects of summer air pollution on respiratory health of asthmatic children.

In the early summer of 1995, the acute respiratory effects of ambient air pollution were studied in a panel of 61 children, ages 7 to 13 yr, of whom 77% were taking asthma medication. Peak flow was measured twice daily with MiniWright meters at home and the occurrence of acute respiratory symptoms and medication use was registered daily by the parents in a diary. Exposure to air pollution was characterized by the ambient concentrations of ozone, PM10, and black smoke. During the study period, maximal 1-h ozone concentrations never exceeded 130 microg/m3, and 24-h black smoke and PM10 concentrations were never higher than 41 and 60 microg/m3 respectively. Associations of air pollution and health outcomes were evaluated using time series analysis. After adjusting for pollen, time trend, and day of the week, black smoke in particular was associated with acute respiratory symptoms and with medication use. Less strong associations were found for PM10 and ozone. These results suggest that in this panel of children, most of whom had asthma, relatively low levels of particulate matter and ozone in ambient air are able to increase symptoms and medication use.

Air Pollution↗
PubMed1997

Chronic respiratory symptoms, skin test results, and lung function as predictors of peak flow variability.

We examined how chronic respiratory symptoms, reported in a questionnaire, and results of skin prick tests and spirometry predicted variability in peak expiratory flow (PEF) among 6-12-yr-old children (n = 1,854). After characterization with skin tests and spirometry, children were followed for 2-3 mo during the winter of 1993-1994. Peak expiratory flow was measured daily in the morning and evenings. Children with asthmatic symptoms (wheeze and/or attacks of shortness of breath with wheeze in the past 12 mo and/or ever doctor diagnosed asthma) had a greater variation in PEF than children with dry nocturnal cough as their only chronic respiratory symptom. Similarly, doctor-diagnosed asthma was associated with a greater variation in PEF, also among children with asthmatic symptoms. Peak flow variability increased with an increasing number of symptoms reported in the questionnaire. Atopy, positive skin test reactions to house dust mite and cat and lowered level (as % of predicted) in FEV1 and in MMEF were also associated with an increased variation in PEF. All the differences were observed in both diurnal and day-to-day variation in PEF. In conclusion, chronic respiratory symptoms reported in a questionnaire, spirometric lung function and skin prick test results among asthmatic children predicted variation in PEF measured during a 2-3 mo follow-up. The difference in morning PEF coefficient of variation (CV) between children with asthmatic symptoms and children with cough only was somewhat bigger in girls than in boys. The effect of atopy on morning PEF CV was somewhat bigger in young than in older children.

Animals↗
PubMed1996

Measurement of beta(1-->3)-glucans in occupational and home environments with an inhibition enzyme immunoassay.

beta (1-->3)-Glucans are known for their potent ability to induce nonspecific inflammatory reactions and are believed to play a role in bioaerosol-induced respiratory symptoms. An inhibition enzyme immunoassay (EIA) was developed for the quantitation of beta (1-->3)-glucans in dust samples from occupational and residential environments. Immunospecific rabbit antibodies were produced by immunization with bovine serum albumin-conjugated laminarin [beta (1-->3)-glucan] and affinity chromatography on epoxy-Sepharose-coupled beta (1-->3)-glucans. The laminarin-based calibration curve in the inhibition EIA ranged from approximately 40 to 3,000 ng/ml (15 to 85% inhibition). Another beta (1-->3)-glucan (curdlan) showed a similar inhibition curve but was three to five times less reactive on a weight basis. Pustulan, presumed to be a beta (1-->6)-glucan, showed a parallel dose-response curve at concentrations 10 times higher than that of laminarin. Control experiments with NaIO4 and beta (1-->3)-glucanase treatment to destroy beta (1-->6)- and beta (1-->3)-glucan structures, respectively, indicate that the immunoreactivity of pustulan in the assay was due to beta (1-->3)-glucan and not to beta (1-->6)-glucan structures. Other polysaccharides, such as mannan and alpha (1-->6)-glucan, did not react in the inhibition EIA. Beta (1-->3)-Glucan extraction of dust samples in water (with mild detergent) was performed by heat treatment (120 degrees C) because aqueous extracts obtained at room temperature did not contain detectable beta (1-->3)-glucan levels. The assay was shown to detect heat-extractable beta (1-->3)-glucan in dust samples collected in a variety of occupational and environmental settings. On the basis of duplicate analyses of dust samples, a coefficient of variation of approximately 25% was calculated. It was concluded that the new inhibition EIA offers a useful method for indoor beta (1-->3)-glucan exposure assessment.

Animals↗
PubMed1996

Chronic respiratory symptoms in children and adults living along streets with high traffic density.

OBJECTIVES: To investigate if the population living along streets with high traffic density has a higher prevalence of chronic respiratory symptoms. METHODS: A sample of 673 adults and 106 children (0-15 years), living along busy traffic streets in the city of Haarlem was compared with a control sample of 812 adults and 185 children living along quiet streets. Exposed and control streets were selected on the basis of model calculations of NO2 concentrations. A postal questionnaire containing questions about respiratory symptoms and several potential confounders was used to collect information from the study subjects. RESULTS: After adjustment for potential confounders, children living along busy streets were found to have a higher prevalence of most respiratory symptoms than children living along quiet streets. Adjusted odds ratios were significant for wheeze and for respiratory medication used. Risk ratios were higher for girls than for boys, with significant adjusted odds ratios between 2.9 and 15.8 for girls. In adults, only mild dyspnoea was more often reported by subjects living along streets with high traffic density. CONCLUSIONS: The results suggest that living along busy streets increases the risk of developing chronic respiratory symptoms in children.

Adolescent↗
PubMed1996

Infant respiratory symptoms in relation to mite allergen exposure.

The relationship between the Dermatophagoides pteronyssinus (Der p) I content of house dust and the respiratory symptoms reported for young infants was studied. One hundred and four infants, aged 3-15 months, were selected during July-September 1993 through the Dutch postnatal health care service, using a short screening questionnaire to identify mothers with respiratory allergy to house dust and/or pets. Forty-eight were selected from this group of mothers ("high risk" infants) and 56 infants were selected when neither of the parents reported allergy or chronic respiratory symptoms ("low risk" infants). All homes were visited in October 1993. Dust samples were collected from the infant's mattress and from other places in the home, and the Der p I content was measured in dust extracts. The results indicate that on more than half of the mattresses, the Der p I level was over 2,000 ng.g-1, the level suggested to be associated with an increased risk of sensitization. Information on respiratory symptoms ("wheeze" and "prolonged cough") experienced since birth was obtained by questionnaire from one of the parents on the dust sampling day. The occurrence of respiratory symptoms in the infants appeared to be positively related to the Der p I concentration of the dust. Although no objective measurements of respiratory symptoms were available, the results of this study suggest that exposure to mite allergen in early life may lead to respiratory symptoms that are suggestive of airway obstruction in the first year of life.

Air Pollution, Indoor↗
PubMed1995

Damp housing and childhood respiratory symptoms: the role of sensitization to dust mites and molds.

In 1990, a case-control study was conducted in the Netherlands into the association between damp housing, childhood respiratory symptoms, and sensitization to house dust mites and mold allergens. In this study, 259 children with chronic respiratory symptoms and 257 control children were involved. Total serum immunoglobulin E (IgE) and specific IgE against house dust mites and a mixture of molds were determined. A visual inspection for signs of home dampness was performed in all homes. A questionnaire was given to the parents of the children to elicit information about the presence of signs of dampness in the previous 2 years and about risk factors for childhood respiratory disease. In the case group, 94 children had elevated serum IgE levels to house dust mites and 24 children to the mixture of molds. In the control group, house dust mite allergy was found in 31 children and mold allergy in two children. In a crude analysis, cases were slightly more likely to have been living in homes where damp or mold was reported or observed than were the controls. In cases as well as controls, home dampness was associated with increased sensitization to dust mites and molds. There was no relation between home dampness and case-control status after stratification for sensitization, however. Restriction of the analysis to cases with elevated serum IgE levels against dust mites and/or molds, and to controls without elevated serum IgE, increased the odds ratios, and several became significant at p < 0.05. This supports a connection between damp housing and sensitization to dust mites and/or molds and childhood respiratory symptoms.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗
PubMed1995

Spirometric reference values for white European children and adolescents: Polgar revisited.

We analyzed six spirometric data sets collected in the Netherlands, Austria, the United Kingdom, Spain, and Italy. The objectives were to establish whether (1) it was possible to describe spirometric indices from childhood to adulthood, taking into account the adolescent growth spurt, and (2) there are systematic differences in ventilatory function between children and adolescents in different parts of Western Europe. The study comprised 2,269 girls and 3,592 boys, aged 6-21 years. The range in standing height was 110-185 in girls, 110-205 in boys. The model applicable to all data sets was ln FVC or ln FEV1 = a + (b + c x A) x H, where H = standing height and A = age; this model prevents the phase shift between the adolescent growth spurt in length and lung volume from leading to an age-dependent bias in predicted values. There was surprising agreement between most of the data sets; systematic differences are probably due to technical factors arising from ATPS-BTPS corrections and from defining the end of breath with pneumotachometer systems. Taking those into account, prediction equations for FVC, FEV1, and FEV1%FVC were developed with "lower limits of normal" which should be applicable to children and adolescents of European descent. It is proposed that the approach of analyzing available data sets should also be applied to other ventilatory indices, data collected in adults and elderly subjects, or in other ethnic groups, and that an international data base be set up to that end.

Adolescent↗
PubMed1995

House dust mite allergen levels in dust from schools with smooth and carpeted classroom floors.

A study was conducted to investigate the levels of house dust mite allergen Der p I in classroom floor dust from 49 schools with smooth (n = 18) or carpeted (n = 31) floors. Schools were located in the city of Rotterdam (n = 29) and in a number of small communities in the Province of Gelderland (n = 20). Data on building characteristics of the schools were obtained. Dust samples were analysed for Der p I content, the major allergen of the house dust mite Dermatophagoides pteronyssinus. The results showed that in schools with carpeted classroom floors, larger amounts of settled dust and higher Der p I levels either expressed as concentrations (in ng/g) or loadings (in ng/m2) were found than in schools with smooth classroom floors. However, the levels of Der p I were considerably lower than in dust collected from floors in homes. Although the Der p I levels were low, effects of several building characteristics on the levels were found. Age of the floor cover, the number of classrooms in the school and the presence of damp spots in the building were related to Der p I concentrations and loadings mainly on carpeted floors. Remarkably, schools in the rural area contained significantly more dust and Der p I than schools in the urban area. We conclude that dust from carpeted classroom floors contains more house dust mite allergen than dust from smooth classroom floors, but much less than dust from floors in homes.

Adolescent↗
PubMed1995

Der p I concentrations in mattress surface and floor dust collected from infants' bedrooms.

BACKGROUND: Allergen exposure in early childhood is thought to be important for sensitization and subsequent development of asthma. Not much is known, however, about exposure of young children to allergens in the home. OBJECTIVES: This study was designed to document dust mite allergen exposure in young children, and to determine whether infants from atopic mothers (= 'high-risk' infants) are exposed to lower concentrations of house dust mite allergen than infants from non-atopic parents (= 'low-risk' infants). METHODS: Dust samples were taken in the homes of 104 infants (48 'high-risk' and 56 'low-risk' infants, selected by questionnaire) aged 3-15 months, from floors in different rooms and from the child's mattress surface. RESULTS: The majority of the infants were found to be exposed to Der p I concentrations of more than 2000 ng/g in dust collected from the surface of their mattresses. Lower Der p I concentrations were found in mattress surface dust from the beds of infants from atopic mothers than of infants from non-atopic parents. Also, lower Der p I concentrations were found in floor dust from the homes of infants from atopic mothers. Infant beds equipped with new mattresses, new blankets and top plastic sheeting had significantly lower Der p I concentrations than beds equipped with used mattresses and blankets, without top plastic sheeting. CONCLUSIONS: Young children in the Netherlands are exposed to significant concentrations of Der p I in mattress surface dust. Allergic parents appear to provide their children with environments somewhat less rich in mite allergen than non-allergic parents.

Allergens↗
PubMed1995

Associations of PM10 and airborne iron with respiratory health of adults living near a steel factory.

The association between daily PM10 (particles with a median aerodynamic diameter of < or = 10 microns) and iron particle concentrations and respiratory health was studied in a population of adults selected for current or recent bronchodilator use. Acute changes in respiratory health were measured as changes in peak expiratory flow (PEF), and daily prevalence of respiratory symptoms and medication use as recorded in a diary. The study period was October 11 through December 22, 1993. The study population included 32 adults living near a large steel industry in Wijk aan Zee, the Netherlands. During the study period, 24-h average PM10 concentrations in Wijk aan Zee ranged from 36 to 137 micrograms/m3 while the 24-h average concentrations of iron, silicon, sodium, and manganese ranged from approximately zero to 6.95, 1.84, 12.02, and 0.37 micrograms/m3 respectively. The steel industry was found to contribute significantly to the PM10 concentrations, and especially to the iron and manganese concentrations in the air. The association of changes in respiratory health with changes in PM10, iron, sodium, and silicon was evaluated using a time series approach. A statistically significant decrease in PEF was found to be associated with increasing PM10 concentrations. Stronger associations were found for smokers than for nonsmokers, and for subjects reporting many chronic respiratory symptoms than for subjects reporting few such symptoms. Increased concentrations of iron tended to be associated with a decline in PEF, with a lag of 2 to 3 d, although the association did not reach statistical significance.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗
PubMed1995

Effect of photochemical air pollution on acute respiratory symptoms in children.

In the spring and summer of 1989, an epidemiologic study of the acute effects of photochemical air pollution on the respiratory health of 300 children 7 to 11 yr old was conducted. The children studied were a general population sample of the children living in two rural towns in the Netherlands. For these children, small pulmonary function decrements associated with ambient ozone concentrations were reported previously. In this paper, the association between photochemical ambient air pollution and acute respiratory symptoms is evaluated. Occurrence of acute respiratory symptoms was registered by the parents of the children in a diary on a daily basis. The association of symptom prevalence and incidence with air pollution was evaluated using a logistic regression model that took auto-correlation of the residuals into account. Several photochemical episodes occurred in the study period of 102 d. Hourly maximum ozone concentrations ranged from 14 to 114 ppb. Daily average PM10 concentrations ranged from 11 to 136 micrograms/m3. Levels of acid aerosol were low. No associations of daily symptom prevalence or incidence with same-day or previous day concentration levels of ozone, PM10, fine particle sulfate, or nitrate were observed.

Acute Disease↗
PubMed1995

Epidemiologic studies on short-term effects of low levels of major ambient air pollution components.

Since the development of the World Health Organization (WHO) Air Quality Guidelines for Europe, a large number of epidemiologic studies have been published documenting effects of major air pollutants on health at concentrations below existing guidelines and standards. In this review, recent studies are discussed that permit some evaluation of short-term health effects observed at exposure levels lower than the current WHO Guidelines or U.S. Environmental Protection Agency (U.S. EPA) standards. Some studies have been conducted at concentration levels that never exceeded existing guidelines or standards. Other studies have been conducted at exposure levels sometimes exceeding current guidelines or standards. The published analyses of several of these studies permit evaluation of low-level health effects either because analyses were restricted to levels not exceeding the guidelines or graphic analyses were reported suggesting effects at these low levels. For ambient ozone, effects on lung function of subjects exercising outdoors have now been documented at 1-hr maximum levels not exceeding 120 micrograms/m3, i.e., half the current U.S. EPA standard. One study even suggests that such effects occur at levels below 100 micrograms/m3. Several studies are now available documenting effects of particulate air pollution on health in the virtual absence of SO2. Effects on mortality and hospital admissions for asthma have been documented at levels not exceeding 100 micrograms/m3, expressed as 24-hr average inhalable particles PM10 concentration. Effects on lung function, acute respiratory symptoms, and medication use have been found at 24-hr average PM10 levels not exceeding 115 micrograms/m3. When the WHO Air Quality Guidelines and the U.S. EPA standard for PM10 were developed, there were no studies available on health effects of PM10. In this review, we include nine studies documenting health effects of measured PM10 at low levels of exposure, indicating that there is now an entirely new epidemiologic database that can be evaluated in the process of revising current guidelines and standards. The low levels of exposure at which effects on health were seen underscore the urgent need for such reevaluations.

Air Pollutants↗
PubMed1994

[House dust mite allergens and COPD in children; a case-control study].

OBJECTIVE: To determine the relationship between mite allergen (Der p I) concentrations in house dust and presence of chronic respiratory symptoms in children. DESIGN: Case control study. SETTING: The provinces of Gelderland and North-Holland in the Netherlands. METHOD: Questionnaires were handed to pupils of 38 schools to take home; about 6000 were returned (80% response). A home visit was paid to 259 children with chronic respiratory symptoms ('cases') and to 257 symptom-free 'control' children. Using an enzyme immunoassay the Der p I concentrations of living room floor dust, bedroom floor dust and mattress dust were determined. Specific IgE was determined in serum. RESULTS: Der p I concentrations higher than 2000 ng/g were found in 86% of the dwellings and concentrations higher than 10,000 ng/g in 55%. Cases were exposed to lower Der p I concentrations than controls. However, cases sensitised to dust mites were exposed to higher Der p I concentrations than non-sensitised cases, both living in homes where no allergen avoidance measures had been taken in the past. CONCLUSION: Exposure to Der p I in the home was associated with sensitisation to dust mites in children with chronic respiratory symptoms living in homes where no allergen avoidance measures had been taken.

Allergens↗
PubMed1994

Effects of low-level winter air pollution concentrations on respiratory health of Dutch children.

During three consecutive winters acute effects of air pollution on respiratory health of more than 1000 children living in four nonindustrial communities in the Netherlands have been investigated. Each child performed between 6 and 10 pulmonary function tests on predetermined days. The occurrence of acute respiratory symptoms in the children was registered in a daily diary filled out by the parents of the children for periods of 3 months. Exposure to air pollution was characterized by the ambient concentration of sulfur dioxide, nitrogen dioxide, PM10, fine particle sulfate, fine particle nitrate, and nitrous acid. No major winter air pollution episode occurred during these winters. Concentrations of acid aerosol were low. A weak negative association between the concentrations of nitrogen dioxide, PM10, aerosol sulfate, aerosol nitrate, nitrous acid, and pulmonary function was found. Sulfur dioxide concentration was not associated with pulmonary function. No association of the concentration of the measured pollutants with daily incidence and prevalence of acute respiratory symptoms was found.

Aerosols↗
PubMed1994

Mite antigen in house dust: relationship with different housing characteristics in The Netherlands.

As part of a case-controlled study on the relationship between home dampness and respiratory symptoms of children, the concentration of the major allergen of Dermatophagoides pteronyssinus (Der p I) in floor dust and mattress dust in 516 dwellings in the Netherlands was measured. A checklist, completed by the investigators, was used to obtain information on home and occupant characteristics, which may have an impact on the Der p I concentration in house dust. The geometric mean mite antigen concentrations were 2370 ng Der p I/g floor dust for the living room, 2201 ng Der p I/g floor dust for the bedroom and 5075 ng Der p I/g mattress dust. In 86% of the houses the maximum concentration was higher than 2000 ng Der p I/g dust, that is regarded as representing a risk for genetically predisposed individuals for the development of specific IgE to house dust mite allergen. In 55% of the houses the maximum concentration exceeded 10,000 ng Der p I/g dust, regarded as a risk factor for acute attacks of asthma for mite allergic patients. The Der p I concentrations in dust from carpeted floors were six to 14 times higher than in dust from floors with a smooth floor covering. Higher Der p I concentrations in floor dust were also significantly associated with increasing age of the dwelling and of the floor covering, with an increasing number of occupants, and with the absence of floor insulation. For mattress dust, the age of the mattress, the presence of an outer cavity wall and mechanical ventilation were important factors. Older mattresses had higher levels, and mattress dust from bedrooms with solid brick outer walls had higher levels than that from bedrooms with outer cavity walls. Mattresses in homes with continuous mechanical ventilation had almost twice lower levels than mattresses in homes with natural ventilation. There was a tendency towards higher Der p I concentrations in dust in homes with reported or observed signs of dampness. The Der p I concentrations in dust from carpeted bedroom floors and mattresses were positively associated with the average relative humidity in the bedroom over a period of 3-6 weeks in a subset of the homes where relative humidity was measured. Similar results were obtained using the concentrations of Der p I in ng/m2 instead of ng/g dust. The results obtained in this study are of importance for planning and evaluating allergen avoidance measures advised to mite allergic patients.

Adult↗
PubMed1994

House dust mite allergen (Der p I) and respiratory symptoms in children: a case-control study.

The association between house dust mite allergen in house dust and childhood respiratory symptoms was investigated in a case-control study of 259 children with reported chronic respiratory symptoms and 257 control children without reported respiratory symptoms. The Der p I concentration in floor dust of the living room and bedroom and in mattress dust was determined using an enzyme immunoassay. Venous blood samples were taken from all children for serum IgE determination against house dust mite (Dermatophagoides pteronyssinus) by radioallergosorbent assay (RAST). A questionnaire was administered to the parents of the children to elicit information about the home, about changes made to the home in the past in relation to respiratory symptoms, and about a number of risk factors for childhood respiratory disease. In 83% of the dwellings of cases and 89% of those of controls, Der p I concentrations higher than 2000 ng/g were found, and in 54% of the dwellings of cases and 57% of those of controls, the concentrations exceeded 10,000 ng/g dust. In a crude analysis, cases were generally exposed to lower Der p I concentrations than controls. Restriction of the analysis to cases sensitized to dust mites, and non-sensitized controls, taking the type of floor covering into account, showed not significantly higher Der p I concentrations in bedroom floor dust of cases. However, restriction of the analysis to cases sensitized to dust mites and cases not sensitized to house dust mites--adjusting for allergen avoidance measures taken in the past--revealed a positive association between the Der p I concentrations in bedroom floor dust and mattress dust and sensitization.(ABSTRACT TRUNCATED AT 250 WORDS)

Allergens↗