| 1. |
- Hedmer, Maria, et al.
(författare)
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Diesel Exhaust Exposure Assessment Among Tunnel Construction Workers—Correlations Between Nitrogen Dioxide, Respirable Elemental Carbon, and Particle Number
- 2017
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Ingår i: Annals of Work Exposures and Health. - : Oxford University Press (OUP). - 2398-7308 .- 2398-7316. ; 61:5, s. 539-553
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Tidskriftsartikel (refereegranskat)abstract
- Objectives: Occupational exposure to diesel exhaust is common due the widespread use of dieselpowered combustion engines. Diesel exhaust is chemically complex and consists of thousands of compounds present as gases and particulate matter. Both nitrogen dioxide (NO2) and elemental carbon(EC) have been used as markers for diesel exhaust exposure. Currently EC is regarded as the best surrogate of diesel exhaust. The objective was to quantify the occupational exposure to diesel exhaust in underground tunnel construction work using a multi-metric approach, and to investigate the correlations between NO2, respirable EC, respirable organic carbon (OC), respirable total carbon(TC), respirable dust (RD), and particle number. Also, the use of NO2 as a proxy for diesel exhaust was evaluated, how much of the variability in the diesel exhaust exposure was attributed to within and between individual factors and if there was a difference between expert and self-administered measurements of NO2. Methods: The personal exposure to diesel exhaust was assessed by expert supervised measurements of NO2, EC, OC, TC, RD and particle number in the breathing zones of underground tunnel workers. Stationary sampling of NO2, EC, OC, TC, RD, size-fractioned mass concentration, and particle number were conducted. The personal and stationary measurements were conducted on threeoccasions simultaneously. The workers measured their exposure by repeated self-administered measurements of NO2. The self-administered measurements were performed twice for each worker with at least one month lag between the samplings. Results: In the simultaneous sampling of diesel exhaust, the geometric mean (GM) concentration of NO2 and respirable EC were 72 μg m−3 (10th–90th percentile 34–140 μg m−3) and 2.6 μg m−3 (10th–90th percentile 1.6–7.3 μg m−3), respectively. The GM for OC and TC was 28 μg m−3 (10th–90th percentile 20–42 μg m−3) and 31 μg m−3 (10th–90th percentile 20–50 μg m−3), respectively. The GM for RD and particle number was 180 μg m−3 (10th–90th percentile 20–530 μg m−3) and 47 900 cm−3 (10th–90th percentile (27 500–94 100 cm−3), respectively. A significant correlation was found between NO2 and respirable EC [Spearman’s correlation r = 0.53 (P = 0.05)]. The within-worker variability of NO2 was 45.5% and the between-worker variability was 54.5%. The self-administered measured concentrations of NO2 (GM 70 μg m−3) did not statistically differ from the NO2 concentrations measured by an expert (P > 0.35).Conclusion: The diesel exhaust exposure in tunnel construction work was low. A significant correlation between NO2 and EC was observed. This indicates that NO2 could be used as a proxy for diesel exhaust in tunnel work if diesel exhaust is the only source of NO2 and if the ratio between EC and NO2 is known and constant. Passive sampling of NO2 is much easier and cheaper to perform compared with active sampling of EC. It is possible to utilize self-administered NO2 measurements in extreme and inaccessible work environments. This study adds support to continued use of NO2 as an exposure marker in combination with EC for diesel exhaust exposure. In tunnel construction work, the variability in the diesel exhaust exposure was high both between- and within-workers.
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| 2. |
- Hossain, Bakhtiar, et al.
(författare)
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Exposure to welding fumes is associated with hypomethylation of the F2RL3 gene: a cardiovascular disease marker.
- 2015
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Ingår i: Occupational and Environmental Medicine. - : BMJ. - 1470-7926 .- 1351-0711. ; 72:12, s. 845-851
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Tidskriftsartikel (refereegranskat)abstract
- Welders are at risk for cardiovascular disease. Recent studies linked tobacco smoke exposure to hypomethylation of the F2RL3 (coagulation factor II (thrombin) receptor-like 3) gene, a marker for cardiovascular disease prognosis and mortality. However, whether welding fumes cause hypomethylation of F2RL3 remains unknown.
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| 3. |
- Li, Huiqi, et al.
(författare)
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A Cross-Sectional Study of the Cardiovascular Effects of Welding Fumes.
- 2015
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Ingår i: PloS one. - : Public Library of Science (PLoS). - 1932-6203. ; 10:7
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Occupational exposure to particulate air pollution has been associated with an increased risk of cardiovascular disease. However, the risk to welders working today remains unclear. We aimed to elucidate the cardiovascular effects of exposure to welding fumes. METHODS: In a cross-sectional study, structured interviews and biological sampling were conducted for 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal breathing zone sampling of respirable dust was performed. Blood pressure (BP) and endothelial function (using peripheral arterial tonometry) were measured. Plasma and serum samples were collected from peripheral blood for measurement of C-reactive protein, low-density lipoprotein, homocysteine, serum amyloid A, and cytokines. RESULTS: Welders were exposed to 10-fold higher levels of particles than controls. Welders had significantly higher BP compared to controls, an average of 5 mm Hg higher systolic and diastolic BP (P≤0.001). IL-8 was 3.4 ng/L higher in welders (P=0.010). Years working as a welder were significantly associated with increased BP (β=0.35, 95%CI 0.13 - 0.58, P=0.0024 for systolic BP; β=0.32, 95%CI 0.16 - 0.48, P<0.001 for diastolic BP, adjusted for BMI) but exposure to respirable dust was not associated with BP. No clear associations occurred between welding and endothelial function, or other effect markers. CONCLUSIONS: A modest increase in BP was found among welders compared to controls suggesting that low-to-moderate exposure to welding fumes remains a risk factor for cardiovascular disease.
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| 4. |
- Li, Huiqi, et al.
(författare)
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Oxidative stress, telomere shortening, and DNA methylation in relation to low-to-moderate occupational exposure to welding fumes.
- 2015
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Ingår i: Environmental and Molecular Mutagenesis. - : Wiley. - 1098-2280 .- 0893-6692. ; 56:8, s. 684-693
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Tidskriftsartikel (refereegranskat)abstract
- Evidence suggests that exposure to welding fumes is a risk factor for lung cancer. We examined relationships between low-to-moderate occupational exposure to particles from welding fumes and cancer-related biomarkers for oxidative stress, changes in telomere length, and alterations in DNA methylation. We enrolled 101 welders and 127 controls (all currently nonsmoking men) from southern Sweden. We performed personal sampling of respirable dust and measured 8-oxodG concentrations in urine using a simplified liquid chromatography tandem mass spectrometry method. Telomere length in peripheral blood was measured by quantitative polymerase chain reaction. Methylation status of 10 tumor suppressor genes was determined by methylation-sensitive high-resolution melting analysis. All analyses were adjusted for age, body mass index, previous smoking, passive smoking, current residence, and wood burning stove/boiler at home. Welders were exposed to respirable dust at 1.2 mg/m(3) (standard deviation, 3.3 mg/m(3) ; range, 0.1-19.3), whereas control exposures did not exceed 0.1 mg/m(3) (P < 0.001). Welders and controls did not differ in 8-oxodG levels (β = 1.2, P = 0.17) or relative telomere length (β = -0.053, P = 0.083) in adjusted models. Welders showed higher probability of adenomatous polyposis coli (APC) methylation in the unadjusted model (odds ratio = 14, P = 0.014), but this was not significant in the fully adjusted model (P = 0.052). Every working year as a welder was associated with 0.0066 units shorter telomeres (95% confidence interval -0.013 to -0.00053, P = 0.033). Although there were no clear associations between concentrations of respirable dust and the biomarkers, there were modest signs of associations between oxidative stress, telomere alterations, DNA methylation, and occupational exposure to low-to-moderate levels of particles. Environ. Mol. Mutagen., 2015. © 2015 Wiley Periodicals, Inc.
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| 5. |
- Xu, Yiyi, et al.
(författare)
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Occupational exposure to particles and mitochondrial DNA : Relevance for blood pressure
- 2017
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Ingår i: Environmental Health: A Global Access Science Source. - : Springer Science and Business Media LLC. - 1476-069X. ; 16:1
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Tidskriftsartikel (refereegranskat)abstract
- Background: Particle exposure is a risk factor for cardiovascular diseases. Mitochondrial DNA (mtDNA) is a primary target for oxidative stress generated by particle exposure. We aimed to elucidate the effects of occupational exposure to particle-containing welding fumes on different biomarkers of mtDNA function, and in turn, explore if they modify the association between particle exposure and cardiovascular response, measured as blood pressure. Methods: We investigated 101 welders and 127 controls (all non-smoking males) from southern Sweden. Personal sampling of the welders’ exposure to respirable dust was performed during work hours (average sampling time: 6.8 h; range: 2.4-8.6 h) and blood pressure was measured once for each subject. We measured relative mtDNA copy number by quantitative PCR and methylation of the mitochondrial regulatory region D-loop and the tRNA encoding gene MT-TF by bisulfite-pyrosequencing. We calculated the relative number of unmethylated D-loop and MT-TF as markers of mtDNA function to explore the modification of mtDNA on the association between particle exposure and blood pressure. General linear models were used for statistical analyses. Results: Welders had higher mtDNA copy number (β = 0.11, p = 0.003) and lower DNA methylation of D-loop (β = −1.4, p = 0.002) and MT-TF (β = −1.5, p = 0.004) than controls. Higher mtDNA copy number was weakly associated with higher personal respirable dust exposure among welders with exposure level above 0.7 mg/m3 (β = 0.037, p = 0.054). MtDNA function modified the effect of welding fumes on blood pressure: welders with low mtDNA function had higher blood pressure than controls, while no such difference was found in the group with high mtDNA function. Conclusion: Increased mtDNA copy number and decreased D-loop and MT-TF methylation were associated with particle-containing welding fumes exposure, indicating exposure-related oxidative stress. The modification of mtDNA function on exposure-associated increase in blood pressure may represent a mitochondria-environment interaction.
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| 6. |
- Li, Huiqi, et al.
(författare)
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Alterations of telomere length and DNA methylation in hairdressers: A cross-sectional study.
- 2016
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Ingår i: Environmental and Molecular Mutagenesis. - : Wiley. - 1098-2280 .- 0893-6692. ; 57:2, s. 159-167
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Tidskriftsartikel (refereegranskat)abstract
- Working as hairdressers has been associated with increased risk for cancer, particularly bladder cancer. To evaluate if current hairdressers have elevated risks of adverse health effects, we measured several biomarkers related to cancer-related DNA alterations. We enrolled 295 hairdressers and 92 non-hairdressers (all female non-smokers) from Stockholm and southern Sweden. Questionnaire data were collected for each participant, including work tasks for the hairdressers. We measured telomere length in peripheral blood leucocytes using quantitative PCR and DNA methylation status of genes relevant for bladder cancer using methylation sensitive high resolution melting analysis. The hairdressers had shorter telomeres (β = -0.069, P = 0.019) compared with non-hairdressers. Shorter telomeres were found in hairdressers up to 32 years old performing hair waving more than once per week as compared with hairdressers in the same age group performing hair waving less often (β = -0.12, P = 0.037). Hair waving was associated with less frequent CDKN2A methylation (odds ratio, OR = 0.19, P = 0.033). Shorter telomeres in hairdressers may indicate a genotoxic effect. Performing hair waving was associated with short telomere length, although the effect was only observed in young hairdressers. No clear patterns were discerned with regard to DNA methylation of bladder cancer-related genes. The observed changes of methylation were not all in the expected direction and warrant further investigation. Environ. Mol. Mutagen., 2015. © 2015 Wiley Periodicals, Inc.
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| 7. |
- Li, Huiqi, et al.
(författare)
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N-nitrosamines are associated with shorter telomere length.
- 2011
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Ingår i: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 37, s. 316-324
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Tidskriftsartikel (refereegranskat)abstract
- OBJECTIVES: Telomeres are critical to maintain the integrity of the chromosomes, and telomere abnormalities are important features of carcinogenesis. Telomere length differs among individuals due to genetic and environmental factors. Aiming to examine the relationship between DNA-damaging agents and average telomere length in peripheral blood, we conducted a cross-sectional study among 157 workers working in the rubber industry in Sweden. METHODS: N-nitrosamines were measured in air by personal sampling on Thermosorb/N tubes and analyzed by liquid chromatography tandem mass spectrometry (LC/MS/MS) for 60 individuals. Based on a similar working situation, the exposure was estimated for all workers. Polycyclic aromatic hydrocarbons (PAH) were measured as the metabolite 1-hydroxypyrene (1-HP) in urine by LC. Carbon disulphide (CS2) was measured as the metabolite 2-thiothiazolidine-4-carboxylic acid (TTCA) in urine by LC/MS/MS. Toluidines (orto-, meta-, and para-) were measured in urine by gas chromatography (GC)/MS. The average telomere length in peripheral blood was determined by quantitative polymerase chain reaction (PCR). RESULTS: There was a reduction in telomere length with increasing exposure to N-nitrosamines in air [measured (N=60) N-nitrosamines β-coefficient= -10, (95% confidence interval [95% CI] -19- -1.2) P=0.026; estimated (N=157) N-nitrosamines β-coefficient = -5.3, (95% CI -9.5- -0.97) P=0.016]. Also, there were negative associations between para-toluidine [β-coefficient= -0.031 (95% CI -0.055- -0.0063) P=0.014], as well as age β-coefficient= -0.005 (95% CI -0.007- -0.002) P=0.001] and telomere length. There were no strong associations between other exposures and telomere length nor did smoking modify the effect. CONCLUSION: N-nitrosamines exposure may lead to telomere shortening.
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| 8. |
- Li, Huiqi, et al.
(författare)
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Telomere length and LINE1 methylation is associated with chromosomal aberrations in peripheral blood.
- 2012
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Ingår i: Genes, Chromosomes and Cancer. - : Wiley. - 1045-2257 .- 1098-2264.
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Tidskriftsartikel (refereegranskat)abstract
- The frequency of chromosomal aberrations in peripheral blood predicts a probable cancer risk. The individual telomere length and methylation of repetitive elements may be susceptibility factors for chromosomal aberrations. A cohort of healthy Norwegian men (N = 364) recruited during 1980-1999 were analyzed for chromosomal aberrations in phytohemagglutinin-stimulated lymphocytes from peripheral blood. Chromosome-type or chromatid-type aberrations were scored. DNA was extracted from slides cytogenetically analyzed and relative average telomere length and methylation of LINE1 repeats were determined by quantitative polymerase chain reaction and bisulfite pyrosequencing, respectively. Information about individuals with malignant tumors (N = 49) diagnosed after chromosomal aberrations testing until end of 2008 was obtained and two matched controls per case were used in a nested case-control analysis. Shorter relative telomere length and higher methylation of LINE1 were associated with higher frequency of total chromosomal aberrations (β = -0.76, P = 0.022; and β = 0.042, P = 0.048, respectively; age-adjusted ordinal regression). The telomere length was stronger associated with chromosome-type (β = -1.00, P = 0.006) than with chromatid-type aberrations (β = -0.49, P = 0.115). The LINE1 methylation was stronger associated with chromatid-type (β = 0.062, P = 0.003) than with chromosome-type aberrations (β = 0.018, P = 0.41). Telomere length [individuals with short telomeres odds ratio (OR) = 0.87, 95% confidence interval (CI) 0.38-2.0], LINE1 (individuals with high methylation OR = 1.04, 95% CI 0.43-2.5) and chromosomal aberrations (individuals with high frequency OR = 1.6, 95% CI 0.63-3.9) at baseline did not predict cancer risk, but the conclusions were hampered by low statistical precision. The results suggest that shorter telomere length and higher LINE1 methylation in peripheral blood lymphocytes are predisposition factors for increased frequency of chromosomal aberrations. © 2012 Wiley Periodicals, Inc.
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