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Analysis of hemoglobin adducts from acrylamide, glycidamide, and ethylene oxide in paired mother/cord blood samples from Denmark.

https://arctichealth.org/en/permalink/ahliterature131736
Source
Chem Res Toxicol. 2011 Nov 21;24(11):1957-65
Publication Type
Article
Date
Nov-21-2011
Author
Hans von Stedingk
Anna C Vikström
Per Rydberg
Marie Pedersen
Jeanette K S Nielsen
Dan Segerbäck
Lisbeth E Knudsen
Margareta Törnqvist
Author Affiliation
Department of Materials and Environmental Chemistry, Environmental Chemistry Unit, Arrhenius Laboratory, Stockholm University, SE-106 91 Stockholm, Sweden.
Source
Chem Res Toxicol. 2011 Nov 21;24(11):1957-65
Date
Nov-21-2011
Language
English
Publication Type
Article
Keywords
Acrylamide - blood
Adult
Case-Control Studies
Chromatography, Liquid
Denmark
Epoxy Compounds - blood
Ethylene Oxide - blood
Female
Fetal Blood - chemistry
Fetus
Hemoglobins - metabolism
Humans
Mass Spectrometry
Maternal Exposure
Placenta - physiology
Pregnancy
Smoking - adverse effects - blood
Abstract
The knowledge about fetal exposure to acrylamide/glycidamide from the maternal exposure through food is limited. Acrylamide, glycidamide, and ethylene oxide are electrophiles and form adducts with hemoglobin (Hb), which could be used for in vivo dose measurement. In this study, a method for analysis of Hb adducts by liquid chromatography-mass spectrometry, the adduct FIRE procedure, was applied to measurements of adducts from these compounds in maternal blood samples (n = 87) and umbilical cord blood samples (n = 219). The adduct levels from the three compounds, acrylamide, glycidamide, and ethylene oxide, were increased in tobacco smokers. Highly significant correlations were found between cord and maternal blood with regard to measured adduct levels of the three compounds. The mean cord/maternal hemoglobin adduct level ratios were 0.48 (range 0.27-0.86) for acrylamide, 0.38 (range 0.20-0.73) for glycidamide, and 0.43 (range 0.17-1.34) for ethylene oxide. In vitro studies with acrylamide and glycidamide showed a lower (0.38-0.48) rate of adduct formation with Hb in cord blood than with Hb in maternal blood, which is compatible with the structural differences in fetal and adult Hb. Together, these results indicate a similar life span of fetal and maternal erythrocytes. The results showed that the in vivo dose in fetal and maternal blood is about the same and that the placenta gives negligible protection of the fetus to exposure from the investigated compounds. A trend of higher levels of the measured adducts in cord blood with gestational age was observed, which may reflect the gestational age-related change of the cord blood Hb composition toward a higher content of adult Hb. The results suggest that the Hb adduct levels measured in cord blood reflect the exposure to the fetus during the third trimester. The evaluation of the new analytical method showed that it is suitable for monitoring of background exposures of the investigated electrophilic compounds in large population studies.
PubMed ID
21882862 View in PubMed
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Associations between plasma concentrations of PCB 28 and possible indoor exposure sources in Danish school children and mothers.

https://arctichealth.org/en/permalink/ahliterature275191
Source
Environ Int. 2016 Feb;87:13-9
Publication Type
Article
Date
Feb-2016
Author
Emilie Lund Egsmose
Elvira Vaclavik Bräuner
Marie Frederiksen
Thit Aarøe Mørck
Volkert Dirk Siersma
Pernille Winton Hansen
Flemming Nielsen
Philippe Grandjean
Lisbeth E Knudsen
Source
Environ Int. 2016 Feb;87:13-9
Date
Feb-2016
Language
English
Publication Type
Article
Keywords
Adolescent
Adult
Air Pollutants - blood
Air Pollution, Indoor - analysis
Child
Construction Materials - analysis
Denmark
Environmental Monitoring - methods
Female
Humans
Linear Models
Male
Mothers
Polychlorinated biphenyls - blood
Schools - standards
Students
Abstract
Polychlorinated biphenyls (PCBs) are ubiquitously present in the environment and are suspected of carcinogenic, neurotoxic and immunotoxic effects. Significantly higher plasma concentrations of the congener PCB 28 occur in children compared to adults. Exposure in schools may contribute to this difference.
To determine whether increased blood plasma concentrations of PCB 28 in Danish school children and mothers are associated with living in homes or attending schools constructed in the PCB period (1959-1977).
PCB 28 was analyzed in plasma samples from 116 children aged 6-11years and 143 mothers living in an urban and a rural area in Denmark and participating in the European pilot project DEMOCOPHES (Demonstration of a study to COordinate and Perform Human Biomonitoring on a European Scale). In Denmark, PCBs were used in construction in the period 1950-1977, and year of construction or renovation of the homes and schools was used as a proxy for indoor PCB exposure. Linear regression models were used to assess the association between potential PCB exposure from building materials and lipid adjusted concentrations of PCB 28 in plasma, with and without adjustment for potential confounders.
Among the 116 children and 143 mothers, we were able to specify home construction period in all but 4 children and 5 mothers leaving 111 children and 138 mothers for our analyses. The median lipid adjusted plasma PCB 28 concentration was 3 (range: 1-28) ng/g lipid in the children and 2 (range: 1-8) ng/g lipid in the mothers. Children living in homes built in the PCB period had significantly higher lipid adjusted plasma PCB 28 concentrations compared to children living in homes built before or after the PCB period. Following adjustment for covariates, PCB 28 concentrations in children were 40 (95% CI: 13; 68) percent higher than concentrations of children living in homes constructed at other times. Furthermore, children attending schools built or substantially refurbished in the PCB period also had significantly higher (46%, 95% CI: 22; 70) PCB 28 concentrations compared to children attending schools constructed before or after the PCB period, while their mothers had similar concentrations. Adjustment for the most prevalent congener, PCB 153, did not change this effect of home or school construction. When both home and school construction year were included in the models, the increase in lipid adjusted plasma PCB 28 for children living in or attending schools from the PCB period was no longer statistically significant. The individual effect of home and school construction periods could not be evaluated further with the available data.
Our results suggest that PCB exposure in the indoor environment in schools and homes constructed during the PCB period may contribute significantly to children's plasma PCB 28 concentration. Efforts to minimize PCB exposure in indoor environments should be considered.
PubMed ID
26638015 View in PubMed
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The Danish contribution to the European DEMOCOPHES project: A description of cadmium, cotinine and mercury levels in Danish mother-child pairs and the perspectives of supplementary sampling and measurements.

https://arctichealth.org/en/permalink/ahliterature267585
Source
Environ Res. 2015 Aug;141:96-105
Publication Type
Article
Date
Aug-2015
Author
Thit A Mørck
Flemming Nielsen
Jeanette K S Nielsen
Janne F Jensen
Pernille W Hansen
Anne K Hansen
Lea N Christoffersen
Volkert D Siersma
Ida H Larsen
Linette K Hohlmann
Mette T Skaanild
Hanne Frederiksen
Pierre Biot
Ludwine Casteleyn
Marike Kolossa-Gehring
Gerda Schwedler
Argelia Castaño
Jürgen Angerer
Holger M Koch
Marta Esteban
Greet Schoeters
Elly Den Hond
Karen Exley
Ovnair Sepai
Louis Bloemen
Reinhard Joas
Anke Joas
Ulrike Fiddicke
Ana Lopez
Ana Cañas
Dominique Aerts
Lisbeth E Knudsen
Source
Environ Res. 2015 Aug;141:96-105
Date
Aug-2015
Language
English
Publication Type
Article
Keywords
Adult
Biological Markers - analysis - blood - urine
Cadmium - analysis - blood - urine
Child
Cotinine - urine
Denmark
Environmental Monitoring - methods - statistics & numerical data
Environmental Pollutants - analysis - blood - urine
Europe
Female
Hair - chemistry
Humans
Male
Mercury - analysis - blood - urine
Middle Aged
Mothers
Questionnaires
Sampling Studies
Seafood - statistics & numerical data
Smoking - urine
Abstract
Human biomonitoring (HBM) is an important tool, increasingly used for measuring true levels of the body burdens of environmental chemicals in the general population. In Europe, a harmonized HBM program was needed to open the possibility to compare levels across borders. To explore the prospect of a harmonized European HBM project, DEMOCOPHES (DEMOnstration of a study to COordinate and Perform Human biomonitoring on a European Scale) was completed in 17 European countries. The basic measurements performed in all implemented countries of DEMOCOPHES included cadmium, cotinine and phthalate metabolites in urine and mercury in hair. In the Danish participants, significant correlations between mothers and children for mercury in hair and cotinine in urine were found. Mercury in hair was further significantly associated with intake of fish and area of residence. Cadmium was positively associated with BMI in mothers and an association between cadmium and cotinine was also found. As expected high cotinine levels were found in smoking mothers. For both mercury and cadmium significantly higher concentrations were found in the mothers compared to their children. In Denmark, the DEMOCOPHES project was co-financed by the Danish ministries of health, environment and food safety. The co-financing ministries agreed to finance a number of supplementary measurements of substances of current toxicological, public and regulatory interest. This also included blood sampling from the participants. The collected urine and blood samples were analyzed for a range of other persistent and non-persistent environmental chemicals as well as two biomarkers of effect. The variety of supplementary measurements gives the researchers further information on the exposure status of the participants and creates a basis for valuable knowledge on the pattern of exposure to various chemicals.
PubMed ID
25440293 View in PubMed
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Effort-reward imbalance at work and risk of sleep disturbances. Cross-sectional and prospective results from the Danish Work Environment Cohort Study.

https://arctichealth.org/en/permalink/ahliterature153741
Source
J Psychosom Res. 2009 Jan;66(1):75-83
Publication Type
Article
Date
Jan-2009
Author
Reiner Rugulies
Malene Norborg
Tilde Sand Sørensen
Lisbeth E Knudsen
Hermann Burr
Author Affiliation
National Research Centre for the Working Environment, Copenhagen, Denmark. rer@nrcwe.dk
Source
J Psychosom Res. 2009 Jan;66(1):75-83
Date
Jan-2009
Language
English
Publication Type
Article
Keywords
Adolescent
Adult
Career Mobility
Cohort Studies
Cross-Sectional Studies
Denmark
Female
Humans
Job Satisfaction
Longitudinal Studies
Male
Middle Aged
Motivation
Occupational Diseases - epidemiology - psychology
Prospective Studies
Reward
Risk factors
Salaries and Fringe Benefits
Self Concept
Sex Factors
Sleep Initiation and Maintenance Disorders - epidemiology - psychology
Workload - psychology
Young Adult
Abstract
This study aimed to analyze if adverse psychosocial working conditions, defined by the model of effort-reward imbalance (ERI), increase the risk of sleep disturbances in the Danish workforce.
Analyses were conducted both cross-sectionally and prospectively in a representative sample of Danish employees. The cross-sectional sample included 2614 participants (50% women) aged 18-59 years, of whom 263 had sleep disturbances. Of the 2351 participants initially free of sleep disturbances, 304 (12.9%) developed sleep disturbances during the 5-year follow-up. Data were analyzed with gender-stratified, multivariate logistic and linear regression analyses, adjusted for numerous covariates.
Cross-sectionally, a 1 S.D. increase in the ERI ratio was associated with sleep disturbances among both men [odds ratio (OR)=1.65, 95% confidence interval (CI)=1.20-2.27] and women (OR=1.82, 95% CI=1.46-2.28). In the prospective analysis, a 1 S.D. increase of the ERI ratio at baseline predicted the onset of sleep disturbances among men (OR=1.39, 95% CI=1.03-1.87) but not among women (OR=0.97, 95% CI=0.76-1.24).
Among men, ERI is a risk factor for the development of sleep disturbances in the Danish workforce. Among women, an association between ERI and sleep disturbances was restricted to the cross-sectional sample. Improving psychosocial working conditions might reduce the risk of sleep disturbances and subsequently also help to prevent clinical disorders related to sleep disturbances.
PubMed ID
19073297 View in PubMed
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Maternal diet, prenatal exposure to dioxin-like compounds and birth outcomes in a European prospective mother-child study (NewGeneris).

https://arctichealth.org/en/permalink/ahliterature266778
Source
Sci Total Environ. 2014 Jun 15;484:121-8
Publication Type
Article
Date
Jun-15-2014
Author
Eleni Papadopoulou
Manolis Kogevinas
Maria Botsivali
Marie Pedersen
Harrie Besselink
Michelle A Mendez
Sarah Fleming
Laura J Hardie
Lisbeth E Knudsen
John Wright
Silvia Agramunt
Jordi Sunyer
Berit Granum
Kristine B Gutzkow
Gunnar Brunborg
Jan Alexander
Helle Margrete Meltzer
Anne Lise Brantsæter
Katerina Sarri
Leda Chatzi
Domenico F Merlo
Jos C Kleinjans
Margaretha Haugen
Source
Sci Total Environ. 2014 Jun 15;484:121-8
Date
Jun-15-2014
Language
English
Publication Type
Article
Keywords
Adult
Birth weight
Cohort Studies
Denmark - epidemiology
Diet - statistics & numerical data
Dioxins - blood
Environmental Policy
Environmental pollutants - blood
Female
Gestational Age
Great Britain - epidemiology
Greece - epidemiology
Health Policy
Humans
Infant, Newborn
Maternal Exposure - statistics & numerical data
Mothers
Pregnancy
Prenatal Exposure Delayed Effects - epidemiology
Spain - epidemiology
Abstract
Maternal diet can result in exposure to environmental contaminants including dioxins which may influence foetal growth. We investigated the association between maternal diet and birth outcomes by defining a dioxin-rich diet. We used validated food frequency questionnaires to assess the diet of pregnant women from Greece, Spain, United Kingdom, Denmark and Norway and estimated plasma dioxin-like activity by the Dioxin-Responsive Chemically Activated LUciferase eXpression (DR-CALUX®) bioassay in 604 maternal blood samples collected at delivery. We applied reduced rank regression to identify a dioxin-rich dietary pattern based on dioxin-like activity (DR-CALUX®) levels in maternal plasma, and calculated a dioxin-diet score as an estimate of adherence to this dietary pattern. In the five country population, dioxin-diet score was characterised by high consumption of red and white meat, lean and fatty fish, low-fat dairy and low consumption of salty snacks and high-fat cheese, during pregnancy. The upper tertile of the dioxin-diet score was associated with a change in birth weight of -121g (95% confidence intervals: -232, -10g) compared to the lower tertile after adjustment for confounders. A small non-significant reduction in gestational age was also observed (-1.4days, 95% CI: -3.8, 1.0days). Our results suggest that maternal diet might contribute to the exposure of the foetus to dioxins and dioxin-like compounds and may be related to reduced birth weight. More studies are needed to develop updated dietary guidelines for women of reproductive age, aiming to the reduction of dietary exposure to persistent organic pollutants as dioxins and dioxin-like compounds.
PubMed ID
24691212 View in PubMed
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Micronucleus frequency in Danish schoolchildren and their mothers from the DEMOCOPHES population.

https://arctichealth.org/en/permalink/ahliterature277231
Source
Mutagenesis. 2016 Jan;31(1):1-8
Publication Type
Article
Date
Jan-2016
Author
Thit A Mørck
Kim Vande Loock
Maria Bech Poulsen
Volkert D Siersma
Jeanette K S Nielsen
Ole Hertel
Micheline Kirsch-Volders
Lisbeth E Knudsen
Source
Mutagenesis. 2016 Jan;31(1):1-8
Date
Jan-2016
Language
English
Publication Type
Article
Keywords
Adult
Child
Denmark
Dioxins - analysis
Environmental monitoring
Female
Humans
Male
Mercury - analysis
Micronuclei, Chromosome-Defective
Micronucleus Tests
Middle Aged
Mothers
Motor Vehicles
Pilot Projects
T-Lymphocytes - ultrastructure
Abstract
Micronucleus (MN) frequency is a biomarker for early genetic effects which is often used in human biomonitoring studies. Increased frequency of micronuclei has been associated with high levels of traffic exposure. Further high MN frequency was found predictive for cancer development in several studies of adults. In the present study, the MN frequency in blood samples from the Danish participants of the European pilot project DEMOCOPHES was analysed and related to the area of residence, self-reported and calculated exposure to road traffic as well as to mercury in hair and blood concentrations of persistent organic pollutants and dioxin-like activity measured in the same participants. The MN frequency analysis was performed with the cytokinesis-block micronucleus (CBMN) assay and included 100 children and 119 mothers. We found a significant correlation between mothers and children in the levels of micronuclei in 1000 binucleated T lymphocytes (‰MNBN) and in the proliferation index. Further the levels of ‰MNBN were significantly higher in mothers compared with their children. No significant associations were found for ‰MNBN for traffic related exposure in neither children nor their mothers. In children, a 2.5 times higher micronuclei in mononuclear T lymphocytes were found in children living within 50 m of a busy road, however, this was not found in mothers or in MNBN and the effect of exposure to road traffic on MN frequency needs further investigation. No significant associations were found between MN frequencies and the other biomarkers measured in the same participants.
PubMed ID
26188196 View in PubMed
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Modelling of human transplacental transport as performed in Copenhagen, Denmark.

https://arctichealth.org/en/permalink/ahliterature260123
Source
Basic Clin Pharmacol Toxicol. 2014 Jul;115(1):93-100
Publication Type
Article
Date
Jul-2014
Author
Line Mathiesen
Thit Aarøe Mørck
Giuseppina Zuri
Maria Helena Andersen
Caroline Pehrson
Marie Frederiksen
Tina Mose
Erik Rytting
Marie S Poulsen
Jeanette K S Nielsen
Lisbeth E Knudsen
Source
Basic Clin Pharmacol Toxicol. 2014 Jul;115(1):93-100
Date
Jul-2014
Language
English
Publication Type
Article
Keywords
Biological Transport
Cloning, Molecular
Denmark
Environmental Pollutants - pharmacokinetics - toxicity
Female
Fetus - drug effects - metabolism
Humans
Maternal-Fetal Exchange - drug effects
Models, Biological
Perfusion - methods
Placenta - drug effects - metabolism
Pregnancy
Risk assessment
Abstract
Placenta perfusion models are very effective when studying the placental mechanisms in order to extrapolate to real-life situations. The models are most often used to investigate the transport of substances between mother and foetus, including the potential metabolism of these. We have studied the relationships between maternal and foetal exposures to various compounds including pollutants such as polychlorinated biphenyls, polybrominated flame retardants, nanoparticles as well as recombinant human antibodies. The compounds have been studied in the human placenta perfusion model and to some extent in vitro with an established human monolayer trophoblast cell culture model. Results from our studies distinguish placental transport of substances by physicochemical properties, adsorption to placental tissue, binding to transport and receptor proteins and metabolism. We have collected data from different classes of chemicals and nanoparticles for comparisons across chemical structures as well as different test systems. Our test systems are based on human material to bypass the extrapolation from animal data. By combining data from our two test systems, we are able to rank and compare the transport of different classes of substances according to their transport ability. Ultimately, human data including measurements in cord blood contribute to the study of placental transport.
PubMed ID
24646015 View in PubMed
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Occupational exposure to the sun and risk of skin and lip cancer among male wage earners in Denmark: a population-based case-control study.

https://arctichealth.org/en/permalink/ahliterature97396
Source
Cancer Causes Control. 2010 Aug;21(8):1347-55
Publication Type
Article
Date
Aug-2010
Author
Line Kenborg
Ane Dahl Jørgensen
Esben Budtz-Jørgensen
Lisbeth E Knudsen
Johnni Hansen
Author Affiliation
Institute of Cancer Epidemiology, Danish Cancer Society, Strandboulevarden 49, 2100 Copenhagen, Denmark. kenborg@cancer.dk
Source
Cancer Causes Control. 2010 Aug;21(8):1347-55
Date
Aug-2010
Language
English
Publication Type
Article
Abstract
OBJECTIVE: We examined the association between outdoor work and the risks of non-melanoma skin cancer, cutaneous malignant melanoma, and lip cancer in a population-based case-control study. METHODS: Among all male wage earners in Denmark, 42,542 cases of non-melanoma skin cancer, 7,690 cases of cutaneous malignant melanoma, and 2,341 cases of lip cancer were identified in the nationwide Danish Cancer Registry. Population controls matched on sex and year of birth were selected at random among wage earners by incidence density sampling. Conditional logistic regression models were used to calculate odds ratios for risks of non-melanoma skin cancer, malignant melanoma, and lip cancer in relation to outdoor work after adjusting for covariates. RESULTS: For outdoor workers employed more than 10 years, the adjusted odds ratios were 0.83 (95% confidence interval (CI) 0.77-0.88) for non-melanoma skin cancer and 1.67 (95% CI 1.38-2.03) for lip cancer. Significantly reduced risk of basal cell cancers on the head, trunk, upper, or lower extremities were observed (range of odds ratios, 0.36 to 0.86). CONCLUSIONS: The results support the hypothesis of a decreased risk of non-melanoma skin cancer and an increased risk of lip cancer among outdoor workers in the Northern Hemisphere.
PubMed ID
20383781 View in PubMed
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Patterns and concentration levels of polybrominated diphenyl ethers (PBDEs) in placental tissue of women in Denmark.

https://arctichealth.org/en/permalink/ahliterature149104
Source
Chemosphere. 2009 Sep;76(11):1464-9
Publication Type
Article
Date
Sep-2009
Author
Marie Frederiksen
Marianne Thomsen
Katrin Vorkamp
Lisbeth E Knudsen
Author Affiliation
Institute of Public Health, University of Copenhagen, Øster Farimagsgade 5A, DK-1014 Copenhagen K, Denmark. mafr@dmu.dk
Source
Chemosphere. 2009 Sep;76(11):1464-9
Date
Sep-2009
Language
English
Publication Type
Article
Keywords
Denmark
Environmental Exposure - analysis
Environmental monitoring
Environmental Pollutants - metabolism
Female
Flame Retardants - metabolism
Halogenated Diphenyl Ethers - metabolism
Humans
Placenta - metabolism
Abstract
The levels and congener patterns of PBDEs were investigated in human placental samples in Denmark. The median concentrations of sigmaPBDE(tri-hepta) and BDE-209 in the 50 samples were 1.22 and 1.14 ng g(-1) lw, respectively, with the total sum ranging from 0.51 to 17.1 ng g(-1) lw, which is similar to previous placental studies. The PBDE content in placental tissue was dominated by BDE-209, which accounted for approximately 50% of the total amount of PBDEs. BDE-47, -99, and -153 were detected in all samples. Approximately equal amounts of BDE-47 and BDE-153 were observed in the placental tissue, which is in agreement with previous European studies of human serum. Principal Component Analysis (PCA) was performed to analyze congener patterns within and between mothers. The loading plot showed groupings of the measured PBDE variables in three groups, representative of Penta-, Octa- and Deca-BDE technical mixtures. Congeners representing the individual technical mixtures were close to orthogonal or inversely correlated, indicating variation in the congener patterns of internal exposure corresponding to the patterns of technical mixtures used in products. Visualisation of the participant objects according to body mass index (BMI), revealed inherent congener patterns (19% X-variance) showing increased frequency for participants within the highest BMI group to have elevated concentrations of BDE-209 in the placental tissue.
PubMed ID
19682725 View in PubMed
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Personal exposure to PM2.5, black smoke and NO2 in Copenhagen: relationship to bedroom and outdoor concentrations covering seasonal variation.

https://arctichealth.org/en/permalink/ahliterature69025
Source
J Expo Anal Environ Epidemiol. 2005 Sep;15(5):413-22
Publication Type
Article
Date
Sep-2005
Author
Mette Sørensen
Steffen Loft
Helle Vibeke Andersen
Ole Raaschou-Nielsen
Lene Theil Skovgaard
Lisbeth E Knudsen
Ivan V Nielsen
Ole Hertel
Author Affiliation
Institute of Public Health, University of Copenhagen, Denmark.
Source
J Expo Anal Environ Epidemiol. 2005 Sep;15(5):413-22
Date
Sep-2005
Language
English
Publication Type
Article
Keywords
Adult
Air Pollutants, Environmental - analysis
Air Pollution, Indoor - analysis
Denmark
Environmental Exposure
Environmental monitoring
Female
Humans
Male
Nitrogen Dioxide - analysis
Particle Size
Research Support, Non-U.S. Gov't
Seasons
Sleep
Smoke
Temperature
Abstract
Epidemiological studies have found negative associations between human health and particulate matter in urban air. In most studies outdoor monitoring of urban background has been used to assess exposure. In a field study, personal exposure as well as bedroom, front door and background concentrations of PM(2.5), black smoke (BS), and nitrogen dioxide (NO(2)) were measured during 2-day periods in 30 subjects (20-33 years old) living and studying in central parts of Copenhagen. The measurements were repeated in the four seasons. Information on indoor exposure sources such as environmental tobacco smoke (ETS) and burning of candles was collected by questionnaires. The personal exposure, the bedroom concentration and the front door concentration was set as outcome variable in separate models and analysed by mixed effect model regression methodology, regarding subject levels as a random factor. Seasons were defined as a dichotomised grouping of outdoor temperature (above and below 8 degrees C). For NO(2) there was a significant association between personal exposure and both the bedroom, the front door and the background concentrations, whereas for PM(2.5) and BS only the bedroom and the front door concentrations, and not the background concentration, were significantly associated to the personal exposure. The bedroom concentration was the strongest predictor of all three pollution measurements. The association between the bedroom and front door concentrations was significant for all three measurements, and the association between the front door and the background concentrations was significant for PM(2.5) and NO(2), but not for BS, indicating greater spatial variation for BS than for PM(2.5) and NO(2). For NO(2), the relationship between the personal exposure and the front door concentration was dependent upon the "season", with a stronger association in the warm season compared with the cold season, and for PM(2.5) and BS the same tendency was seen. Time exposed to burning of candles was a significant predictor of personal PM(2.5), BS and NO(2) exposure, and time exposed to ETS only associated with personal PM(2.5) exposure. These findings imply that the personal exposure to PM(2.5), BS and NO(2) depends on many factors besides the outdoor levels, and that information on, for example, time of season or outdoor temperature and residence exposure, could improve the accuracy of the personal exposure estimation.
PubMed ID
15674319 View in PubMed
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16 records – page 1 of 2.