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Biomedical subjects

B Brunekreef

Publications and source records attributed to B Brunekreef.

At least 91 records · Page 5Linked to original sources
PubMed2000

Increased levels of markers of microbial exposure in homes with indoor storage of organic household waste.

As part of environmental management policies in Europe, separate collection of organic household waste and nonorganic household waste has become increasingly common. As waste is often stored indoors, this policy might increase microbial exposure in the home environment. In this study we evaluated the association between indoor storage of organic waste and levels of microbial agents in house dust. The levels of bacterial endotoxins, mold beta(1-->3)-glucans, and fungal extracellular polysaccharides (EPS) of Aspergillus and Penicillium species were determined in house dust extracts as markers of microbial exposure. House dust samples were collected in 99 homes in The Netherlands selected on the basis of whether separated organic waste was present in the house. In homes in which separated organic waste was stored indoors for 1 week or more the levels of endotoxin, EPS, and glucan were 3.2-, 7.6-, and 4. 6-fold higher, respectively (all P < 0.05), on both living room and kitchen floors than the levels in homes in which only nonorganic residual waste was stored indoors. Increased levels of endotoxin and EPS were observed, 2.6- and 2.1-fold (P < 0.1), respectively, when separated organic waste was stored indoors for 1 week or less, whereas storage of nonseparated waste indoors had no effect on microbial agent levels (P > 0.2). The presence of textile floor covering was another major determinant of microbial levels (P < 0.05). Our results indicate that increased microbial contaminant levels in homes are associated with indoor storage of separated organic waste. These increased levels might increase the risk of bioaerosol-related respiratory symptoms in susceptible people.

Air Pollution, Indoor↗
PubMed2000

(1-->3)-beta-D-glucan and endotoxin in house dust and peak flow variability in children.

House dust-associated bacterial endotoxins have been shown to be associated with asthma severity, and a similar role has been suggested for fungal (1-->3)-beta-D-glucans. In this study the relation between these agents and peak expiratory flow (PEF) variability was investigated in 148 children 7 to 11 yr of age of whom 50% had self- or parent-reported chronic respiratory symptoms. All children self-monitored twice daily their PEF for a period of 16 wk. Dust samples were collected from mattresses and from living room and bedroom floors, and endotoxin and (1-->3)-beta-D-glucan were measured in dust extracts. The relations with mean daily PEF variability (Ampl%mean) were investigated by linear regression analysis, adjusting for dust mite allergen levels, presence of pets, and type of floor cover. In unadjusted analyses the levels of both endotoxin and (1--> 3)-beta-D-glucan per square meter of living room floor were significantly associated with PEF-variability (but not when expressed per gram of sampled dust), particularly in atopic children with asthma symptoms. Adjusted analyses showed the same association for (1--> 3)-beta-D-glucan but not for endotoxin. Although no associations were found with microbial agent levels in bedroom floor or mattress dust, high levels of (1-->3)-beta-D-glucan in living room floor dust apparently increase PEF variability in asthmatic children.

Air Pollution, Indoor↗
PubMed2000

Immune biomarkers in relation to exposure to particulate matter: a cross-sectional survey in 17 cities of Central Europe.

Human population data on air pollution and its effects on the immune system are scarce. A survey was conducted within the framework of the Central European Study of Air Quality and Respiratory Health (CESAR) to measure a panel of immune biomarkers in children of Bulgaria, Czech Republic, Hungary, Poland, Romania, and Slovakia. Seventeen cities were chosen to represent a wide range of exposure to outdoor air pollution. In each, ambient particulate matter of less than 10 microns diameter and less than 2.5 microns diameter (PM10 and PM2.5) were measured with a Harvard impactor. Blood was collected from 366 school children aged 9 to 11 yr between 11 April and 10 May 1996. The percentage of B, total T, CD4+, CD8+, and natural killer (NK) lymphocytes was determined by flow cytometry (Becton Dickinson); total immunoglobulins of class G, M, A and E (IgG, IgM, IgA, and IgE) were measured in serum using nephelometry (Behring). Associations between PM and each log-transformed biomarker concentration were studied by linear regression, in a two-stage model. The yearly average concentrations varied from 41 to 96 micrograms/m3 for PM10 across the 17 study areas, from 29 to 67 micrograms/m3 for PM2.5, and from 12 to 38 micrograms/m3 for PM10-2.5 (coarse). Number of B, CD4+, CD8+, and NK lymphocytes increased with increasing concentration of PM, having adjusted for age, gender, parental smoking, laboratory of analysis, and recent respiratory illness. Differences in lymphocyte number were larger and statistically significant for exposure to PM2.5. Similar results were found when we examined the association between PM and lymphocyte number separately for each laboratory. Total IgG was increased with increasing concentration of PM, significantly in the case of PM2.5. When we repeated the analyses with two other statistical approaches the results did not differ from those reported here. The effect of coarse PM on lymphocyte numbers appears small in comparison to PM2.5. One possible interpretation of our findings is that long-term exposure to airborne particulates leads to inflammation of the airways and activation of the cellular and humoral immune system.

Air Pollutants↗
PubMed1999

Effects of ambient air pollution on upper and lower respiratory symptoms and peak expiratory flow in children.

BACKGROUND: Previous epidemiological studies have shown acute effects of increased amounts of ambient air pollution on the prevalence of respiratory symptoms in children with respiratory disorders. We investigated whether children with bronchial hyperresponsiveness (BHR) and relatively high serum concentrations of total IgE (>60 kU/L, the median value) are susceptible to air pollution. METHODS: We collected data from children during three winters (1992-95) in rural and urban areas of the Netherlands. Lower respiratory symptoms (wheeze, attacks of wheezing, shortness of breath), upper respiratory symptoms (sore throat, runny or blocked nose), and peak expiratory flow were recorded daily for 3 months. The acute effects of airborne particulate matter with a diameter of less than 10 microm, black smoke, sulphur dioxide, and nitrogen dioxide were estimated by logistic regression. FINDINGS: 459 (73%) of 632 children had complete data. Of these, 26% had BHR and relatively high (above median) serum total IgE, 36% had no BHR and total IgE of 60 kU/L or less, 15% had BHR and total IgE of 60 kU/L or less, and 23% had a total IgE of more than 60 kU/L but no BHR. In children with BHR and relatively high serum total IgE the prevalence of lower respiratory symptoms increased significantly by between 32% and 139% for each 100 microm/m3 increase in particulate matter, and between 16% and 131% for each 40 microm/m3 increase in black smoke, SO2, or NO2. Decrease in peak expiratory flow of more than 10% in that group was more common with increased airborne particulate matter and black smoke. There were no consistent positive or negative associations between increased air pollution and prevalence of respiratory symptoms or decrease in peak expiratory flow in the other three groups of children. INTERPRETATION: Children with BHR and relatively high concentrations of serum total IgE are susceptible to air pollution. Although our odds ratios were rather low (range 1.16-2.39) the overall effect of air pollution on public health is likely to be substantial since these odds ratios refer to large numbers of people.

Air Pollutants↗
PubMed1999

Double-blind intervention trial on modulation of ozone effects on pulmonary function by antioxidant supplements.

The aim of this study was to investigate whether the acute effects of ozone on lung function could be modulated by antioxidant vitamin supplementation in a placebo-controlled study. Lung function was measured in Dutch bicyclists (n = 38) before and after each training session on a number of occasions (n = 380) during the summer of 1996. The vitamin group (n = 20) received 100 mg of vitamin E and 500 mg of vitamin C daily for 15 weeks. The average ozone concentration during exercise was 77 microg/m3 (range, 14-186 microg/m3). After exclusion of subjects with insufficient compliance from the analysis, a difference in ozone exposure of 100 microg/m3 decreased forced expiratory volume in 1 second (FEV1) 95 ml (95% confidence interval (CI) -265 to -53) in the placebo group and 1 ml (95% CI -94 to 132) in the vitamin group; for forced vital capacity, the change was -125 ml (95% CI -384 to -36) in the placebo group and -42 ml (95% CI -130 to 35) in the vitamin group. The differences in ozone effect on lung function between the groups were statistically significant. The results suggest that supplementation with the antioxidant vitamins C and E confers partial protection against the acute effects of ozone on FEV1 and forced vital capacity in cyclists.

Adolescent↗
PubMed1999

Fungal extracellular polysaccharides in house dust as a marker for exposure to fungi: relations with culturable fungi, reported home dampness, and respiratory symptoms.

BACKGROUND: Epidemiologic studies have demonstrated an association between indoor fungal growth and respiratory symptoms. However, in only a few studies was fungal exposure actually measured. OBJECTIVE: The purpose of this study was to evaluate the measurement by enzyme immunoassay of extracellular polysaccharides of Aspergillus and Penicillium species (EPS-Asp/Pen ) in house dust as a marker for fungal exposure and to study the relations between EPS-Asp/Pen levels and home dampness and respiratory symptoms in children. METHODS: Extracts of house dust samples from bedroom and living room floors and mattresses from homes of 31 children with chronic respiratory symptoms and 29 children with no chronic respiratory symptoms were analyzed for EPS-Asp/Pen. RESULTS: EPS-Asp/Pen were readily detectable (40 to 46,513 nanogram equivalent/g dust) in 161 house dust extracts, with highest concentrations in living room floor dust. EPS-Asp/Pen levels were 2 to 3 times higher on carpeted floors than on smooth floors. EPS-Asp/Pen were significantly correlated with total culturable fungi (r = 0.3 to 0.5) and with house dust mite allergens (r = 0.3 to 0.5). EPS-Asp/Pen levels in living room floor dust were positively associated with occupant-reported home dampness. This was not observed for EPS-Asp/Pen in bedroom floor and mattress dust. EPS-Asp/Pen levels in living room floor dust were positively associated with respiratory symptoms. EPS-Asp/Pen in bedroom floor and mattress dust showed a reversed association with respiratory symptoms, possibly because of allergen-avoidance measures taken in the bedroom. CONCLUSION: The enzyme immunoassay for fungal EPS-Asp/Pen may be a useful method for exposure assessment of indoor fungi.

Antigens, Fungal↗
PubMed1999

Plasma concentrations of the antioxidants beta-carotene and alpha-tocopherol in relation to lung function.

OBJECTIVE: To study the association between plasma antioxidants (beta-carotene and alpha-tocopherol) and lung function in Dutch adults aged 20-59 y. DESIGN: Cross-sectional. SETTING: Population-based study. SUBJECTS: A random sample (n=367) was drawn from all participants (men and women) aged 20-59 y with reproducible lung function measurements in 1995. INTERVENTION: Completion of general questionnaire and physical examination. MAIN OUTCOME MEASUREMENTS: Forced expiratory volume in 1 s (FEV1), forced vital capacity (FVC) and plasma levels of beta-carotene and alpha-tocopherol. RESULTS: SUBJECTS with a high plasma beta-carotene level (90th percentile, that is 0.57 micromol/L) tended to have a higher FEV1 (73 ml, s.e.m. 60 ml; P=0.22) and a higher FVC (147 ml, s.e.m. 76 ml; P=0.05) than subjects with a low plasma beta-carotene level (10th percentile, that is 0.11 micromol/L) after adjustment for age, height, gender, smoking status, pack-years of smoking and alcohol consumption. There was no difference in lung function between subjects with high and low plasma alpha-tocopherol concentrations. CONCLUSIONS: The results suggest that subjects with a high plasma beta-carotene tended to have a higher FVC than subjects with a low plasma beta-carotene concentration which was borderline statistically significant. The difference for FEV1 between high and low levels of plasma beta-carotene tended to be in the same positive direction as that of FVC but did not reach the pre-set statistical significance level. There is no relation between plasma alpha-tocopherol and lung function. SPONSORSHIP: Ministry of Public Health, Welfare and Sports of the Netherlands and the National Institute of Public Health and the Environment.

Adult↗
PubMed1999

Effects of house dust mite avoidance measures on Der p 1 concentrations and clinical condition of mild adult house dust mite-allergic asthmatic patients, using no inhaled steroids.

BACKGROUND: Exposure to house dust mite (HDM) allergens often results in worsening of asthma. Therefore, avoidance of exposure to HDM allergens is often proposed. Unfortunately, the most effective and feasible avoidance strategy is still not completely assessed. Consequently, we investigated the effects of a combined HDM avoidance strategy on HDM allergen concentrations and clinical condition of allergic, mild asthmatic, patients using no inhaled steroids. METHODS: Asthmatic patients, allergic to HDM, using no inhaled corticosteroids, were randomly allocated to an active (n = 76) or a placebo allergen-avoidance group (n = 81). Avoidance measures consisted of applying Acarosan(R) (placebo: water) to the living room and bedroom floors, and the use of HDM-impermeable covers for mattresses and bedding (placebo: cotton covers for mattresses only). Effects on allergen concentrations (Der p 1), FEV1, bronchial hyperresponsiveness, peak flow parameters and asthma symptom scores were studied during 20 weeks and controlled for the allergic status of the patients. RESULTS: The active covers reduced Der p 1 concentrations to 9.4% (P = 0.0001), and were always significant lower than in the placebo group (P = 0.0002). Acarosan(R) resulted in slight but significant decreases (twofold, P = 0.0001), both on living room and bedroom floors, but concentrations were never significantly lower than the placebo group. Although the combined avoidance strategy resulted in a considerable reduction in allergen load in the active group, no differences were seen between the two groups in any of the clinical parameters during the follow-up period in this group of allergic asthmatics, using no inhaled corticosteroids. Corrections for the allergic status did not alter these results. CONCLUSIONS: The combined avoidance strategy was effective in reducing HDM allergen concentration. This was especially achieved by the allergen-impermeable covers, while the effects of Acarosan(R) were only marginal. However, this allergen reduction was not reflected in a convincing improvement in clinical condition in this group of mild allergic asthmatics, using no inhaled steroids. Perhaps, a longer follow-up period would have resulted in more pronounced effects.

Administration, Inhalation↗
PubMed1999

Self-reporting versus parental reporting of acute respiratory symptoms of children and their relation to pulmonary function and air pollution.

BACKGROUND: Studies of acute effects of outdoor air pollution on acute respiratory symptoms in children generally rely on reports by parents. Little is known about the validity of parental reporting of symptoms of their children. We therefore compared symptoms reported by the parents with self-reported symptoms and measured pulmonary function of 741 7-11-year-old Dutch children. We also analysed the association of symptoms reported by the child or parent and outdoor air pollution. METHODS: The parents of the children completed a daily diary of symptoms of their children for about 3 months. The children reported presence of acute respiratory symptoms in the preceding week before a pulmonary function test was conducted (6-10 test days). RESULTS: Children reported between 80% and 220% more acute respiratory symptoms than their parents for them in the same period. The agreement between symptom reports by the parent and the child was low to moderate (Kappa between 0.22 for eye irritation and 0.43 for fever). Presence of cough reported by child or parent was associated with similar small decrements in forced vital capacity (FVC), forced expiratory volume in one second (FEV1.0) and especially peak expiratory flow (PEF) and maximal mid-expiratory flow (FEF25-75). The largest pulmonary function decrements were found when symptoms were reported by both parent and child. Symptoms reported by either child or parent were not associated with air pollution. CONCLUSIONS: Symptom reports of the children were more prevalent but did not agree well with parental reports. The similar association with pulmonary function suggested that self-reported symptoms were neither superior nor inferior to symptoms reported by the parents.

Acute Disease↗
PubMed1999

Acute effects of urban air pollution on respiratory health of children with and without chronic respiratory symptoms.

OBJECTIVES: To investigate to what extent different components of air pollution are associated with acute respiratory health effects in children with and without chronic respiratory symptoms. METHODS: During three consecutive winters starting in 1992-3, peak expiratory flow (PEF) and respiratory symptoms were registered daily in panels of children of 7-11 years old with and without symptoms, living in urban areas with high traffic intensity in The Netherlands. Simultaneously, panels of children living in non-urban areas were studied. Daily measurements of particles with aerodynamic diameter < 10 microns (PM10), black smoke (BS), sulphate, SO2, and NO2 were performed in both areas. RESULTS: The contrast in particle concentrations (PM10, BS, and sulphate) between urban and non-urban areas was small, but there was more contrast in the concentrations of SO2 and NO2. In children with symptoms from both areas, significant associations were found between PM10, BS, and sulphate concentrations and the prevalence of symptoms of the lower respiratory tract (LRS) and decrements in PEF. Particle concentrations were also associated with use of bronchodilators in the urban areas, but not in the non-urban areas. After stratification by use of medication, stronger associations were found in children who used medication than in children who did not use medication. The magnitude of the estimated effects was in the order of a twofold increase in the use of bronchodilators, a 50% increase in LRS, and an 80% increase in decrements in PEF for a 100 micrograms/m3 increase in the 5 day mean PM10 concentration. In children without symptoms, significant associations were found between concentrations of PM10 and BS and decrements in PEF in both areas, but these associations were smaller than those for children with symptoms. No associations with respiratory symptoms were found. CONCLUSIONS: The results suggest that children with symptoms are more susceptible to the effects of particulate air pollution than children without symptoms, and that use of medication for asthma does not prevent the adverse effects of particulate air pollution in children with symptoms.

Air Pollution↗
PubMed1999

Inhomogeneity in response to air pollution in European children (PEACE project).

OBJECTIVES: The PEACE study is a multicentre panel study of the acute effects of particles with a 50% cut off aerodynamic diameter of 10 microns (PM10), black smoke (BS), sulphur dioxide (SO2), and nitrogen dioxide (NO2) on respiratory health of children with chronic respiratory symptoms. In the complete panels no consistent association between air pollution and respiratory health was found. The study evaluated whether potentially more sensitive subgroups in the panels did show effects of air pollution. METHODS: To evaluate heterogeneity in response to air pollution, effect estimates of air pollution on peak expiratory flow (PEF) and respiratory symptoms were calculated in subgroups based on presence of chronic respiratory symptoms, use of respiratory medication, atopy, sex, and baseline lung function. RESULTS: The association between PEF and air pollution was positive in asthmatic children who used respiratory medication whereas the associations tended to be negative in children who did not use respiratory medication selected only on cough. No consistent association was found among asthmatic children who did not use medication. The association between daily prevalence of symptoms and concentrations of air pollution was not different between these subgroups. CONCLUSION: None of the predefined potentially more sensitive subgroups showed a consistent association between air pollution, PEF, and respiratory symptoms.

Air Pollutants↗
PubMed1999

Mass concentration and elemental composition of PM10 in classrooms.

OBJECTIVES: To investigate the sources of high concentrations of particles of < 10 microns diameter (PM10) in classrooms, observed in a previous study on childhood exposure to PM10, and to study the correlation between classroom and outdoor concentrations of mass and elements of PM10. METHODS: Measurements of PM10 were conducted in two schools and outdoors in Amsterdam, the Netherlands. Averaging time was 24 hours for the outdoor measurements and both 8 hours (school time) and 24 hours for the classroom measurements. Analysis by x ray fluorescence was used to measure the elemental composition of 55 samples from the 11 days when measurements were conducted simultaneously in both classrooms and outdoors. RESULTS: For most elements, classroom concentrations were considerably higher than outdoor concentrations, especially during school hours. The highest classroom/outdoor ratios were found for the elements from soils Si, Ca, and Ti. The only measured elements that were not increased were S, Br, Pb, and Cl, which are dominated by non-crustal sources. For S, Br, and Pb, which are generally associated with particles < 1 micron, significant correlations between classroom and outdoor concentrations and between the two classrooms were found. The other elements generally had low correlations. CONCLUSIONS: The results show that the high PM10 concentrations found in our classrooms are probably due to resuspension of coarse particles or suspension of soil material. Due to these excess coarse particles, the correlation between classroom and outdoor concentrations is lower for elements associated with coarse particles than for elements associated with fine particles. As the general composition of PM10 in classrooms differs from the composition of PM10 in ambient air, the high PM10 mass concentrations in classrooms can probably not be directly compared with ambient air quality guidelines.

Air Pollutants↗
PubMed1999

Influence of shift work and host factors on endotoxin-related acute peak flow changes.

There is limited knowledge about which internal and external factors influence respiratory effects of occupational endotoxin exposure. Relationships between endotoxin exposure, work-related respiratory symptoms, and acute peak flow changes were studied in 97 shift workers in the potato processing industry. For each worker, across-shift peak flow changes were determined for morning, afternoon, and night shifts. A higher endotoxin exposure was associated with an increased prevalence of work-related symptoms, a smaller peak expiratory flow (PEF) increase across the morning shift, and a larger PEF decrease across afternoon and night shifts. The largest effects occurred during the afternoon shift. No consistent differences between smokers and nonsmokers, and between atopics and nonatopics were observed. We conclude that endotoxin exposure in the potato processing industry is related to across-shift peak flow changes and the occurrence of work-related respiratory symptoms. The host factors smoking and atopy are not important confounding or effect-modifying factors in these relationships. In respiratory health studies among shift workers, it is important to investigate all work shifts before drawing definitive conclusions about exposure-response relationships.

Adult↗