| 1. |
- Fall, Tove, et al.
(författare)
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Early Exposure to Dogs and Farm Animals and the Risk of Childhood Asthma
- 2015
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Ingår i: JAMA pediatrics. - Stockholm : American Medical Association. - 2168-6203 .- 2168-6211. ; 169:11
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Tidskriftsartikel (refereegranskat)abstract
- IMPORTANCE: The association between early exposure to animals and childhood asthma is not clear, and previous studies have yielded contradictory results.OBJECTIVE: To determine whether exposure to dogs and farm animals confers a risk of asthma.DESIGN, SETTING AND PARTICIPANTS: In a nationwide cohort study, the association between early exposure to dogs and farm animals and the risk of asthma was evaluated and included all children born in Sweden from January 1, 2001, to December 31, 2010 (N = 1 011 051), using registry data on dog and farm registration, asthma medication, diagnosis, and confounders for parents and their children. The association was assessed as the odds ratio (OR) for a current diagnosis of asthma at age 6 years for school-aged children and as the hazard ratio (HR) for incident asthma at ages 1 to 5 years for preschool-aged children. Data were analyzed from January 1, 2007, to September 30, 2012.EXPOSURES: Living with a dog or farm animal.MAIN OUTCOMES AND MEASURES: Childhood asthma diagnosis and medication used.RESULTS: Of the 1 011 051 children born during the study period, 376 638 preschool-aged (53 460 [14.2%] exposed to dogs and 1729 [0.5%] exposed to farm animals) and 276 298 school-aged children (22 629 [8.2%] exposed to dogs and 958 [0.3%] exposed to farm animals) were included in the analyses. Of these, 18 799 children (5.0%) in the preschool-aged children's cohort experienced an asthmatic event before baseline, and 28 511 cases of asthma and 906 071 years at risk were recorded during follow-up (incidence rate, 3.1 cases per 1000 years at risk). In the school-aged children's cohort, 11 585 children (4.2%) experienced an asthmatic event during the seventh year of life. Dog exposure during the first year of life was associated with a decreased risk of asthma in school-aged children (OR, 0.87; 95% CI, 0.81-0.93) and in preschool-aged children 3 years or older (HR, 0.90; 95% CI, 0.83-0.99) but not in children younger than 3 years (HR, 1.03; 95% CI, 1.00-1.07). Results were comparable when analyzing only first-born children. Farm animal exposure was associated with a reduced risk of asthma in both school-aged children and preschool-aged children (OR, 0.48; 95% CI, 0.31-0.76, and HR, 0.69; 95% CI, 0.56-0.84), respectively.CONCLUSIONS AND RELEVANCE: In this study, the data support the hypothesis that exposure to dogs and farm animals during the first year of life reduces the risk of asthma in children at age 6 years. This information might be helpful in decision making for families and physicians on the appropriateness and timing of early animal exposure.
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| 2. |
- Kumar, Jitender, et al.
(författare)
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Influence of persistent organic pollutants on oxidative stress in population-based samples
- 2014
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Ingår i: Chemosphere. - : Elsevier BV. - 0045-6535 .- 1879-1298. ; 114, s. 303-309
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Tidskriftsartikel (refereegranskat)abstract
- Persistent organic pollutants (POPs) are a large group of chemicals widely used and produced in various industrial applications. Many cell culture/animal studies have shown that POPs can induce oxidative stress. Since such data is lacking in humans, we conducted a large population-based study to analyze associations between POPs and oxidative stress markers. We measured following POPs; 16 polychlorinated biphenyls (PCBs), 5 organochlorine (OC) pesticides, octachlorinated dibenzo-p-dioxin, and polybrominated diphenyl ether 47, and oxidative stress markers; homocysteine, reduced [GSH] and oxidized glutathione [GSSG], glutathione ratio [GSSG/GSH], total glutathione, oxidized low-density lipoprotein [ox-LDL], ox-LDL antibodies, conjugated dienes, baseline conjugated dienes of LDL, and total anti-oxidative capacity in plasma samples collected from 992 70-year old individuals (50% women) from the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. Linear regression analyses were performed to study the associations between oxidative stress markers and summary measures of POPs including the total toxic equivalence (TEQ), sums of PCBs and BC pesticides (main exposures) while adjusting for potential confounders. In multivariable-adjusted analyses, sum of PCBs showed strong associations with ox-LDL (beta = 0.94; P = 2.9 * 10(-6)). Further, sum of PCBs showed association with glutathione-related markers (GSSG: beta = 0.01; P = 6.0 *10(-7); GSSG/GSH: beta = 0.002; P = 9.7 * 10(-10)), although in reverse direction. Other summary measures did not show any significant association with these markers. In our study of elderly individuals from the general population, we show that plasma levels of POPs are associated with markers of increased oxidative stress thereby suggesting that even low dose background exposure to POPs may be involved in oxidative stress. (C) 2014 Elsevier Ltd. All rights reserved.
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| 3. |
- Kumar, Jitender, et al.
(författare)
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Influence of persistent organic pollutants on the complement system in a population-based human sample
- 2014
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 71, s. 94-100
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Tidskriftsartikel (refereegranskat)abstract
- Background: Persistent organic pollutants (POPS) are toxic compounds generated through various industrial activities and have adverse effects on human health. Studies performed in cell cultures and animals have revealed that POPs can alter immune-system functioning. The complement system is part of innate immune system that helps to clear pathogens from the body. We performed a large-scale population-based study to find out associations between summary measures of different POPs and different complement system markers.Methods: In this cross-sectional study, 16 polychlorinated biphenyls (PCBs), 3 organochlorine (OC) pesticides, octachloro-p-dibenzodioxin, and 2,2',4,4'-tetrabromodiphenyl ether (BDE-47) were analyzed for their association with levels of protein complement 3 (C3), 3a (C3a), 4 (C4) and C3a/C3 ratio. A total of 992 individuals (all aged 70 years, 50% females) were recruited from the Prospective Investigation of the Vasculature in Uppsala Seniors cohort. Regression analysis adjusting for a variety of confounders was performed to study the associations of different POP exposures (total toxic equivalency value or TEQ and sum of 16 PCBs) with protein complements.Results: The TEQ values were found to be positively associated with C3a (beta = 0.07, 95% CI = 0.017-0.131, p = 0.01) and C3a/C3 ratio (beta = 0.07, 95% Cl = 0.015-0.126, p = 0.01) taking possible confounders into account. The association observed was mainly driven by PCB-126.Conclusion: In this study involving 992 elderly individuals from the general population, we showed that POPs, mainly PCB-126, were associated with levels of complement system markers indicating that the association of these toxic compounds with downstream disease could be mediated by activation of immune system. (C) 2014 Elsevier Ltd. All rights reserved.
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| 4. |
- Kumar, Jitender, et al.
(författare)
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Persistent Organic Pollutants and Inflammatory Markers in a Cross-Sectional Study of Elderly Swedish People : The PIVUS Cohort
- 2014
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Ingår i: Journal of Environmental Health Perspectives. - : National Institute of Environmental Health Science. - 0091-6765 .- 1552-9924. ; 122:9, s. 977-983
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Tidskriftsartikel (refereegranskat)abstract
- BACKGROUND: Persistent organic pollutants (POPs) are compounds that are generated through various industrial activities and released in the surrounding environment. Different animal studies have shown effects of different POPs on various inflammatory markers.OBJECTIVE: Because very few studies have been conducted in humans, we assessed the associations between different POPs and inflammatory markers in a large population-based sample of elderly men and women (all 70 years of age) from Sweden.METHODS: This cross-sectional study investigated the concentrations of several polychlorinated biphenyls (PCBs), organochlorine pesticides, polychlorinated dibenzo-p-dioxin, and brominated diphenyl ether congeners and their association with a number of inflammatory markers [vascular cell adhesion molecule 1 (VCAM-1), intercellular adhesion molecule 1 (ICAM-1), E-selectin, C-reactive protein (CRP), total leucocyte count, tumor necrosis factor alpha (TNF-alpha), monocyte chemotactic protein 1 (MCP-1), and interleukin 6 (IL-6)] in 992 individuals. These individuals were recruited from the Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. We used a total toxic equivalency (TEQ) value that measures toxicological effects with the relative potencies of various POPs.RESULTS: Following adjustment for potential confounders, the TEQ value (driven mainly by PCB-126) was significantly associated with levels of ICAM-1 (p < 10(-5)). A similar trend was also observed between sum of PCBs and VCAM-1 (p < 0.001). No significant associations were observed between levels of POPs and other inflammatory markers.CONCLUSIONS: TEQ values were associated with levels of ICAM-1, to a lesser degree also with VCAM-1, but not with CRP and several other inflammatory markers. These findings suggest an activation of vascular adhesion molecules by POPs, and particularly by PCB-126.
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| 5. |
- Kumar, Jitender, et al.
(författare)
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Persistent organic pollutants and liver dysfunction biomarkers in a population-based human sample of men and women
- 2014
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 134, s. 251-256
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Tidskriftsartikel (refereegranskat)abstract
- Background and objective: Persistent organic pollutants (POPs) are stable organic compounds generated through different industrial activities. Liver is involved in the metabolism of POPs, and hence exposure to POPs may interfere with liver function. Although a few studies have shown adverse effects of POPs on liver function, large-scale studies involving humans are lacking. We performed this large population-based cross-sectional study to assess the associations between different POPs and liver dysfunction biomarkers.Methods: A total of 992 individuals (all aged 70 years, 50% males) were recruited as part of Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) cohort. The total toxic equivalency (TEQ) value was calculated for seven mono-ortho and two non-ortho substituted polychlorinated biphenyls (PCBs) and octachloro-p-dibenzodioxin (OCDD) to assess their toxicological effects. The association of TEQ values, summary measures of 16 PCBs (sum of PCBs) and three organochlorine pesticides (sum of OC pesticides) with liver dysfunction biomarkers (bilirubin; alkaline phosphatase, ALP; alanine amino-transferase, ALT; and gamma-glutamyltransferase, GGT) was analyzed utilizing linear regression analysis.Results: The mono-ortho PCB TEQ values were found to be significantly positively associated with bilirubin (beta=0.71, P=0.008), while sum of OC pesticide concentrations was negatively associated with ALP (beta= -0.02, P=0.002) after adjusting for various potential confounders. When analyzed individually, a number of different POPs were associated with ALP, ALT and bilirubin. No such association with GGT was observed.Conclusion: Various POPs including PCBs, OCDD and pesticides were associated with the liver dysfunction biomarkers bilirubin, ALT and ALP, suggesting adverse effects on liver function from these environmental pollutants. (C) 2014 Elsevier Inc. All rights reserved.
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| 6. |
- Lind, Lars, et al.
(författare)
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Genetic and methylation variation in the CYP2B6 gene is related to circulating p,p '-dde levels in a population-based sample
- 2017
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Ingår i: Environment International. - Oxford, United Kingdom : Elsevier. - 0160-4120 .- 1873-6750. ; 98, s. 212-218
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Since the metabolism of the organochlorine pesticide dichlorodiphenyltrichloroethane (DDT) is not fully known in humans, we evaluated if circulating levels of a major breakdown product of DDT, p,p'-DDE, were related to genome-wide genetic and methylation variation in a population-based sample.Methods: In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects all aged 70), circulating levels of p, p'-DDE were analyzed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/HRMS). Genetic variants were genotyped and imputed (1000 Genomes reference, March 2012 release). Methylation sites were assayed using the Illumina HumanMethylation450 array in whole blood. A genome-wide association study (GWAS) approach was applied.Results: Evidence for genome-wide significant association with p,p'-DDE levels was observed only for a locus at chromosome 19 corresponding to the CYP2B6 gene (lead SNP rs7260538). Subjects being homozygote for the G allele showed a median level of 472 ng/g lipid, while the corresponding level for those being homozygote for the T allelewas 192 ng/g lipid (p= 1.5x10(-31)). An analysis conditioned on the lead SNP disclosed a distinct signal in the same gene (rs7255374, position chr19: 41520351; p= 2.2 x 10(-8)). A whole-genome methylation analysis showed one significant relationship vs. p,p'-DDE levels (p= 6.2 x 10(-9)) located 7 kb downstreamthe CYP2B6 gene (cg27089200, position chr19: 41531976). This CpG-sitewas also related to the lead SNP (p = 3.8 x 10(-35)), but mediated only 4% of the effect of the lead SNP on p, p'-DDE levels.Conclusion: Circulating levels of p, p'-DDE were related to genetic variation in the CYP2B6 gene in the general elderly population. DNA methylation in this gene is not closely linked to the p, p'-DDE levels.
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| 7. |
- Lind, Lars, et al.
(författare)
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Genetic variation in the CYP1A1 gene is related to circulating PCB118 levels in a population-based sample
- 2014
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 133, s. 135-140
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Tidskriftsartikel (refereegranskat)abstract
- Several of the polychlorinated biphenyls (PCBs), i.e. the dioxin-like PCBs, are known to induce the P450 enzymes CYP1A1, CYP1A2 and CYP1B1 by activating the aryl hydrocarbon receptor (Ah)-receptor. We evaluated if circulating levels of PCBs in a population sample were related to genetic variation in the genes encoding these CYPs. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (1016 subjects all aged 70), 21 SNPs in the CYP1A1, CYP1A2 and CYP1B1 genes were genotyped. Sixteen PCB congeners were analysed by high-resolution chromatography coupled to high-resolution mass spectrometry (HRGC/ HRMS). Of the investigated relationships between SNPs in the CYP1A1, CYP1A2 and CYP1B1 and six PCBs (congeners 118, 126, 156, 169, 170 and 206) that captures > 80% of the variation of all PCBs measured, only the relationship between CYP1A1 rs2470893 was significantly related to PCB118 levels following strict adjustment for multiple testing (p=0.00011). However, there were several additional SNPs in the CYP1A2 and CYP1B1 that showed nominally significant associations with PCB118 levels (p-values in the 0.003-0.05 range). Further, several SNPs in the CYP1B1 gene were related to both PCB156 and PCB206 with p-values in the 0.005-0.05 range. Very few associations with p < 0.05 were seen for PCB126, PCB169 or PCB170. Genetic variation in the CYP1A1 was related to circulating PCB118 levels in the general elderly population. Genetic variation in CYP1A2 and CYP1B1 might also be associated with other PCBs.
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| 8. |
- Lind, Lars, et al.
(författare)
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Global DNA hypermethylation is associated with high serum levels of persistent organic pollutants in an elderly population
- 2013
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 59, s. 456-461
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Tidskriftsartikel (refereegranskat)abstract
- Dioxin exposure has experimentally been associated with changes in DNA methylation, an epigenetic change that is associated with disease. The present study aims to investigate if serum levels of dioxin and other persistent environmental pollutants are related to global DNA methylation in a human sample. In the population-based Prospective Investigation of the Vasculature in Uppsala Seniors (PIVUS) study (all aged 70), global DNA methylation was measured by the Luminometric Methylation Assay in 524 subjects. Twenty-three different POPs, including 16 PCBs, five pesticides, one dioxin (OCDD) and one brominated flame retardant (BDE47) were analysed by HRGC/HRMS. Ten single nucleotide polymorphisms (SNPs) in the Aryl hydrocarbon (Ah)-receptor were analysed by mini-sequencing. High levels of toxic equivalency (TEQ) for PCBs and dioxin were associated with DNA hypermethylation (p = 0.030). This was mainly attributed to coplanar non-ortho PCBs. While no significant associations were found between DNA methylation and SNPs in the Ah-receptor, an interaction was found between the SNP rs2237297 and TEQ so that TEQ was associated with hypermethylation (p = 0.009) only in subjects with one G-allele (n = 103). Also high levels of the PCB126 congener, the OCDD, and the pesticide metabolite p,p'-DDE were related to DNA hypermethylation (p = 0.01, 0.03 and 0.003, respectively). In conclusion, in a sample of elderly subjects, high TEQ including PCBs and the dioxin OCDD and high serum levels of PCB126, OCDD, and p,p'-DDE were related to global DNA hypermethylation in a cross-sectional analysis. (C) 2013 Elsevier Ltd. All rights reserved.
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| 9. |
- Magnusson, Patrik K. E., et al.
(författare)
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The Swedish Twin Registry : establishment of a biobank and other recent developments
- 2013
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Ingår i: Twin Research and Human Genetics. - Cambridge, United Kingdom : Cambridge University Press. - 1832-4274 .- 1839-2628. ; 16:1, s. 317-329
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Tidskriftsartikel (refereegranskat)abstract
- The Swedish Twin Registry (STR) today contains more than 194,000 twins and more than 75,000 pairs have zygosity determined by an intra-pair similarity algorithm, DNA, or by being of opposite sex. Of these, approximately 20,000, 25,000, and 30,000 pairs are monozygotic, same-sex dizygotic, and opposite-sex dizygotic pairs, respectively. Since its establishment in the late 1950s, the STR has been an important epidemiological resource for the study of genetic and environmental influences on a multitude of traits, behaviors, and diseases. Following large investments in the collection of biological specimens in the past 10 years we have now established a Swedish twin biobank with DNA from 45,000 twins and blood serum from 15,000 twins, which effectively has also transformed the registry into a powerful resource for molecular studies. We here describe the main projects within which the new collections of both biological samples as well as phenotypic measures have been collected. Coverage by year of birth, zygosity determination, ethnic heterogeneity, and influences of in vitro fertilization are also described.
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| 10. |
- Ng, Esther, et al.
(författare)
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Genome-wide association study of plasma levels of polychlorinated biphenyls disclose an association with the CYP2B6 gene in a population-based sample
- 2015
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Ingår i: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 140, s. 95-101
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Tidskriftsartikel (refereegranskat)abstract
- Background: Polychlorinated biphenyls (PCBs) are a group of man-made environmental pollutants which accumulate in humans with adverse health effects. To date, very little effort has been devoted to the study of the metabolism of PCBs on a genome-wide level.Objectives: Here, we conducted a genome-wide association study (GWAS) to identify genomic regions involved in the metabolism of PCBs.Methods: Plasma levels of 16 PCBs ascertained in a cohort of elderly individuals from Sweden (n=1016) were measured using gas chromatography-high resolution mass spectrophotometry (GC-HRMS). DNA samples were genotyped on the Infinium Omni Express bead microarray, and imputed up to reference panels from the 1000 Genomes Project. Association testing was performed in a linear regression framework under an additive model.Results: Plasma levels of PCB-99 demonstrated genome-wide significant association with single nucleotide polymorphisms (SNPs) mapping to chromosome 19q13.2. The SNP with the strongest association was rs8109848 (p=3.7 x 10(-13)), mapping to an intronic region of CYP2B6. Moreover, when all PCBs were conditioned on PCB-99, further signals were revealed for PCBs -74, -105 and -118, mapping to the same genomic region. The lead SNPs were rs8109848 (p=3.8 x 10(-12)) for PCB-118, rs4802104 (p= 1.4 x 10(-9)) for PCB-74 and rs4803413 (p=2.5 x 10(-9)) for PCB-105, all of which map to CYP2B6.Conclusions: In our study, we found plasma levels of four lower-chlorinated PCBs to be significantly associated with the genetic region mapping to the CYP2B6 locus. These findings show that CYP2B6 is of importance for the metabolism of PCBs in humans, and may help to identify individuals who may be susceptible to PCB toxicity. (C) 2015 The Authors. Published by Elsevier Inc.
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