| 1. |
- Abera, Asmamaw, et al.
(author)
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Measurements of nox and development of land use regression models in an east-African city
- 2021
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In: Atmosphere. - : MDPI AG. - 2073-4433. ; 12:4
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Journal article (peer-reviewed)abstract
- Air pollution causes premature mortality and morbidity globally, but these adverse health effects occur over proportionately in low-and middle-income countries. Lack of both air pollution data and knowledge of its spatial distribution in African countries have been suggested to lead to an underestimation of health effects from air pollution. This study aims to measure nitrogen oxides (NOx), as well as nitrogen dioxide (NO2), to develop Land Use Regression (LUR) models in the city of Adama, Ethiopia. NOx and NO2 was measured at over 40 sites during six days in both the wet and dry seasons. Throughout the city, measured mean levels of NOx and NO2 were 29.0 µg/m3 and 13.1 µg/m3, respectively. The developed LUR models explained 68% of the NOx variances and 75% of the NO2. Both models included similar geographical predictor variables (related to roads, industries, and transportation administration areas) as those included in prior LUR models. The models were validated by using leave-one-out cross-validation and tested for spatial autocorrelation and multicollinearity. The performance of the models was good, and they are feasible to use to predict variance in annual average NOx and NO2 concentrations. The models developed will be used in future epidemiological and health impact assessment studies. Such studies may potentially support mitigation action and improve public health.
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| 2. |
- Engström, Karin, et al.
(author)
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Early Pregnancy Exposure to Ambient Air Pollution among Late-Onset Preeclamptic Cases Is Associated with Placental DNA Hypomethylation of Specific Genes and Slower Placental Maturation
- 2021
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In: Toxics. - : MDPI AG. - 2305-6304. ; 9:12, s. 1-23
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Journal article (peer-reviewed)abstract
- Exposure to ambient air pollution during pregnancy has been associated with an increased risk of preeclampsia (PE). Some suggested mechanisms behind this association are changes in placental DNA methylation and gene expression. The objective of this study was to identify how early pregnancy exposure to ambient nitrogen oxides (NOx) among PE cases and normotensive controls influence DNA methylation (EPIC array) and gene expression (RNA-seq). The study included placentas from 111 women (29 PE cases/82 controls) in Scania, Sweden. First-trimester NOx exposure was assessed at the participants’ residence using a dispersion model and categorized via median split into high or low NOx. Placental gestational epigenetic age was derived from the DNA methylation data. We identified six differentially methylated positions (DMPs, q < 0.05) comparing controls with low NOx vs. cases with high NOx and 14 DMPs comparing cases and controls with high NOx. Placentas with female fetuses showed more DMPs (N = 309) than male-derived placentas (N = 1). Placentas from PE cases with high NOx demonstrated gestational age deceleration compared to controls with low NOx (p = 0.034). No differentially expressed genes (DEGs, q < 0.05) were found. In conclusion, early pregnancy exposure to NOx affected placental DNA methylation in PE, resulting in placental immaturity and showing sexual dimorphism.
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| 3. |
- Mandakh, Yumjirmaa, et al.
(author)
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Association of prenatal ambient air pollution exposure with placental mitochondrial DNA copy number, telomere length and preeclampsia
- 2021
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In: Frontiers in Toxicology. - : Frontiers Media S.A.. - 2673-3080. ; 3
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Journal article (peer-reviewed)abstract
- Background: Studies have shown that ambient air pollution is linked to preeclampsia (PE), possibly via generation of oxidative stress in the placenta. Telomere length and mitochondrial DNA copy number (mtDNAcn) are sensitive to oxidative stress damage. Objective: To study the association between prenatal exposure to ambient nitrogen oxides (NOx, a marker for traffic-related air pollution), and PE, as well as potential mediation effects by placental telomere length and mtDNAcn.Methods: This is a cross-sectional study of 42 preeclamptic and 95 arbitrarily selected normotensive pregnant women with gestational ambient NOx exposure assessment in southern Scania, Sweden. Hourly concentrations of NOx were estimated at the residential addresses by a Gaussian-plume dispersion model with 100 × 100 m spatial resolutions and aggregated into trimester-specific mean concentrations. Placental relative mtDNAcn and telomere length were measured using qPCR. Linear and logistic regression models were used to investigate associations, adjusted for perinatal and seasonal characteristics.Results: Exposure was categorized into low and high exposures by median cut-offs during first [11.9 μg/m3; interquartile range (IQR) 7.9, 17.9], second (11.6 μg/m3; IQR: 7.1, 21.1), third trimesters (11.9 μg/m3; IQR: 7.7, 19.5) and entire pregnancy (12.0 μg/m3; IQR: 7.6, 20.1). Increased risk of PE was found for high prenatal NOx exposure during the first trimester (OR 4.0; 95% CI: 1.4, 11.1; p = 0.008), and entire pregnancy (OR 3.7; 95% CI: 1.3, 10.4; p = 0.012). High exposed group during the first trimester had lower placental relative mtDNAcn compared with low exposed group (−0.20; 95% CI: −0.36, −0.04; p = 0.01). Changes in relative mtDNAcn did not mediate the association between prenatal NOx exposure and PE. No statistically significant association was found between placental relative telomere length, prenatal NOx exposure and PE.Conclusion: In this region with relatively low levels of air pollution, ambient NOx exposure during the first trimester was associated with reduced placental relative mtDNAcn and an increased risk of PE. However, we did not find any evidence that mtDNAcn or TL mediated the association between air pollution and PE. Future research should further investigate the role of mtDNAcn for pregnancy complications in relation to exposure to ambient air pollution during pregnancy.
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| 4. |
- Mandakh, Yumjirmaa, et al.
(author)
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Maternal Exposure to Ambient Air Pollution and Risk of Preeclampsia : A Population-Based Cohort Study in Scania, Sweden
- 2020
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In: International Journal of Environmental Research and Public Health. - : MDPI AG. - 1660-4601. ; 17:5
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Journal article (peer-reviewed)abstract
- The aim of this study was to investigate the risk of developing preeclampsia (PE) associated with gestational exposure to ambient air pollutants in southern Sweden, a low-exposure area. We used a cohort of 43,688 singleton pregnancies and monthly mean exposure levels of black carbon (BC), local and total particulate matter (PM2.5 and PM10), and NOX at the maternal residential address estimated by Gaussian dispersion modeling from 2000 to 2009. Analyses were conducted using binary logistic regression. A subtype analysis for small-for-gestational age (SGA) was performed. All analyses were adjusted for obstetrical risk factors and socioeconomic predictors. There were 1286 (2.9%) PE cases in the analysis. An adjusted odds ratio (AOR) of 1.35 with a 95% confidence interval (CI) of 1.11-1.63 was found when comparing the lowest quartile of BC exposure to the highest quartile in the third trimester The AOR for PE associated with each 5 µg/m3 increase in locally emitted PM2.5 was 2.74 (95% CI: 1.68, 4.47) in the entire pregnancy. Similar patterns were observed for each 5 µg/m3 increment in locally emitted PM10. In pregnancies complicated by PE with SGA, the corresponding AOR for linear increases in BC was 3.48 (95% CI: 1.67, 7.27). In this low-level setting, maternal exposure to ambient air pollution during gestation was associated with the risk of developing PE. The associations seemed more pronounced in pregnancies with SGA complications, a finding that should be investigated further.
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| 5. |
- Mandakh, Yumjirmaa
(author)
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Placental molecular mechanisms as pathways linking prenatal exposure to ambient air pollution to preeclampsia and fetal growth
- 2023
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Doctoral thesis (other academic/artistic)abstract
- Background: Preeclampsia (PE) is a “multifactorial syndrome” in which ambient air pollution may contribute to the etiology of PE. However, the underlying mechanism of this association is not clearly elucidated. This dissertation aims at understanding the placental molecular mechanism underlying the relationship of prenatal exposure to ambient air pollution with preeclampsia and fetal growth by characterizing and evaluating the mediator role of placental aging using mitochondrial DNA content, telomere length, DNA methylation and gene expression analyses.Methods: Scania in Sweden and Barcelona in Spain are the two main study areas. Maternal Air Pollution in Southern Sweden (MAPSS) is a population-based cohort consisting of 43,688 singleton pregnancies recorded from 2000 to 2009 in Scania, Sweden. For placental molecular studies, we selected a sub- cohort of 361 mother-child pairs from the Barcelona Life Study Cohort (BiSC), a prospective cohort consisting of 1080 mother-child pairs recruited between 2018 and 2021 as well as 137 participants from unique biobank designed to study PE at Lund University. Each individual-level air pollutant concentrations were estimated either by a high-resolution dispersion model or by a passive sampling methods. Placental mtDNAcn and TL were measured using qPCR. Placental DNAm and gene expression were analyzed with EPIC array and RNA-seq, respectively. Linear, logistic regression and linear mixed effects models were used on SPSS and R statistical programs.Results: In a setting with fair air quality in Scania, the increased risk of PE and SGA were associated with both linear exposure trend and quartile-specific exposure of ambient particles and NOx. In a setting with moderate air quality in Barcelona, early pregnancy exposure to ambient NO2 measured by home- outdoor and personal sensors were associated with lower birth weight and increased odds of having SGA neonate. Although the mediatory role of placental mtDNAcn and telomere length were not confirmed, prenatal exposure to ambient NOx and NO2 affect the placental aging process differently depending on the exposure concentration and exposure period during pregnancy. We observed reduced mtDNAcn and shorter TL in placenta in relation to exposure during first trimester, whereas increased mtDNAcn in relation to NO2 exposure during third trimester. Prenatal exposure to ambient NOx during first trimester affected differential placental DNA methylation in PE and NOx combined groups, resulting in placental age deceleration and showing sexual dimorphism.Conclusion: Placental senescence and aging may be the underlying molecular mechanism linking the association between prenatal exposure to ambient air pollution and pregnancy complications including preeclampsia and small-for-gestational age foetuses and neonates.
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