| 1. |
- Hammarstrand, Sofia, et al.
(författare)
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Perfluoroalkyl substances (PFAS) in drinking water and risk for polycystic ovarian syndrome, uterine leiomyoma, and endometriosis: A Swedish cohort study
- 2021
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 157
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Tidskriftsartikel (refereegranskat)abstract
- Background: Perfluorinated substances (PFAS) are chemicals with endocrine disruptive properties that may interfere with the female reproductive system. However, few studies have explored the association between benign gynecological diseases and high PFAS exposure. Objectives: The aim of this study was to investigate the possible associations between PFAS exposure and subsequent diagnosis of polycystic ovarian syndrome (PCOS), uterine leiomyoma (fibroids), and endometriosis in a cohort exposed to PFAS through drinking water. Material and methods: In 2013, high levels (with sum of PFAS above 10,000 ng/L), dominated by perfluorooctanesulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS), were found in the drinking water from one of the two waterworks in Ronneby, Sweden. The contamination came from firefighting foams used at a nearby airfield. Females of all ages (n = 29,106) who had ever resided in the municipality between 1985 and 2013 formed a cohort. Individual exposure was assessed based on municipality waterworks distribution data linked to annual residential address data; 27% of the females had ever lived at an address with PFAS-contaminated water. Gynecological health outcomes were retrieved from the Swedish National Patient Register. The Cox proportional hazards model was used to estimate the association between exposure and each diagnosis. Results: There were in all 161 cases of PCOS, 1,122 cases of uterine leiomyoma, and 373 cases of endometriosis. In women aged 20-50 years (n = 18,503), those with the highest estimated PFAS exposure had increased hazard ratios (HR) for PCOS (HR = 2.18; 95% confidence interval (CI) 1.43, 3.34) and uterine leiomyoma (HR = 1.28; 95% CI 0.95, 1.74). No increased HR for endometriosis was found (HR = 0.74; 95% CI 0.42, 1.29). Conclusions: Exposure to high levels of PFAS in drinking water was associated with increased risk of PCOS and possibly uterine leiomyoma, but not endometriosis. The findings for PCOS are consistent with prior studies reporting positive associations between PCOS and PFAS exposure at background levels.
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| 2. |
- Li, Ying, et al.
(författare)
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Determinants of serum half-lives for linear and branched perfluoroalkyl substances after long-term high exposure-A study in Ronneby, Sweden
- 2022
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 163
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Tidskriftsartikel (refereegranskat)abstract
- Background: Per-and polyfluoroalkyl substances (PFAS) are persistent substances with surfactant and repellent properties. Municipal drinking water contaminated with PFAS had been distributed for decades to one third of households in Ronneby, Sweden. The source was firefighting foam used in a nearby airfield since the mid-1980s. Clean water was provided from December 16, 2013. Aims: The purpose was to estimate serum half-lives and their determinants in the study population for different PFAS. Methods: Up to ten blood samples were collected between 2014 and 2018 from 114 participants (age 4-84 years at entry, 53% female). 19 PFAS were analysed. Linear mixed models were used to estimate the half-lives. Results: Eight PFAS were increased in Ronneby: perfluorooctanoic acid (PFOA), perfluoropentane sulfonate (PFPeS), perfluorohexane sulfonate (PFHxS), perfluoroheptane sulfonate (PFHpS), linear perfluorooctane sulfonate (L-PFOS) and three branched perfluorooctane sulfonates (1 m-PFOS, 3/4/5m-PFOS and 2/6m-PFOS). The mean estimated half-lives (in years) were 0.94 (95 %CI 0.86-1.02) for PFPeS, 2.47 (2.27-2.7) for PFOA, 2.67 (2.51-2.85) for 2/6m-PFOS, 2.73 (2.55-2.92) for L-PFOS, 3.43 (3.19-3.71) for 3/4/5m-PFOS, 4.52 (4.14-4.99) for PFHxS, 4.55 (4.14-5.06) for PFHpS, and 5.01 (4.56-5.55) for 1 m-PFOS. The most important determinants of a shorter half-life were young age, and better kidney function measured by estimated glomerular filtration rate and ratio of paired urine and serum PFAS levels, followed by female sex during their fertile period aged 15-50. Markers of gut inflammation and reduced permeability i.e. zonulin and calprotectin were also possibly associated with shorter half-life. The results also suggested a time-dependent PFAS elimination process, with more rapid elimination in the first year after the end of exposure. Conclusion: The half-life estimates are in line with past estimates for some PFAS such as PFOA, and the novel results for different PFOS isomers. These results provide observational support for elimination routes - renal, fecal and maternal.
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| 3. |
- Xu, Yiyi, et al.
(författare)
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Association between serum concentrations of perfluoroalkyl substances (PFAS) and expression of serum microRNAs in a cohort highly exposed to PFAS from drinking water
- 2020
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 136
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Tidskriftsartikel (refereegranskat)abstract
- Background: Perfluoroalkyl substances (PFAS) are widespread synthetic substances with various adverse health effects. Not much is known about the modes of action of PFAS toxicity, but one likely mechanism is alteration of microRNA expression. Objectives: To investigate whether PFAS exposure is associated with altered microRNA expression in serum. Methods: We selected women from the Ronneby cohort, with high exposure to perfluorooctane sulfonic acid (PFOS) and perfluorohexane sulfonic acid (PFHxS), emanating from drinking water contaminated by firefighting foam, and a control group of women from a neighbouring municipality without drinking water contamination. Serum levels of PFAS were analysed using LC/MS/MS. High coverage microRNA expression was analysed by next generation sequencing (NGS) in 53 individuals to screen for microRNAs associated with PFAS exposure. After verification by qPCR, associations between PFAS exposure and expression of 18 selected microRNAs were validated by qPCR in 232 individuals. In silico functional analyses were performed using Ingenuity pathway analysis (IPA). Results: Three microRNAs were consistently associated with PFAS exposure in the different steps of the study: miR-101-3p, miR-144-3p and miR-19a-3p (all downregulated with increasing exposure). In silico functional analyses suggested that these PFAS-associated microRNAs were annotated to e.g. cardiovascular function and disease, Alzheimer's disease, growth of cancer cell lines and cancer. Seven predicted target genes for the downregulated microRNAs were annotated to PFAS in IPA knowledge database: DNA methyltransferase 3 alpha (DNMT3 alpha), epidermal growth factor receptor (EGFR), 3-hydroxy-3-methylglutaryl-CoA reductase (HMGCR), nuclear receptor subfamily 1, group H, member 3 (NR1H3), peroxisome proliferator-activated receptor alpha (PPAR alpha), prostaglandin-endoperoxide synthase 2 (PTGS2), and tumour growth factor alpha (TGF alpha). Discussion: PFAS exposure was associated with downregulation of specific microRNAs. Further, in silico functional analyses suggest potential links between the specific PFAS-associated microRNAs, specific microRNA target genes and possibly also health effects.
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| 4. |
- Xu, Yiyi, et al.
(författare)
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Associations between long-term exposure to low-level air pollution and risk of chronic kidney disease—findings from the Malmö Diet and Cancer cohort
- 2022
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 160
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Tidskriftsartikel (refereegranskat)abstract
- Background: Associations between air pollution and chronic kidney disease (CKD) have been reported, but studies at low exposure levels and relevant exposure time windows are still warranted. This study investigated clinical CKD at low air pollution levels in the Swedish Malmö Diet and Cancer Cohort in different exposure time windows. Methods: This study included 30,396 individuals, aged 45–74 at enrollment 1991–1996. Individual annual average residential outdoor PM2.5, PM10, nitrogen oxides (NOx), and black carbon (BC) were assigned using dispersion models from enrollment to 2016. Diagnoses of incident CKD were retrieved from national registries. Cox proportional hazards models were used to obtain hazard ratios (HRs) for CKD in relation to three time-dependent exposure time windows: exposure at concurrent year (lag 0), mean exposure in the 1–5 or 6–10 preceding years (lag 1–5 and lag 6–10), and baseline exposure. Results: During the study period, the average annual residential exposures were 16 μg/m3 for PM10, 11 μg/m3 for PM2.5, 26 μg/m3 for NOx, and 0.97 μg/m3 for BC. For lag 1–5 and lag 6–10 exposure, significantly elevated HRs for incident CKD were found for total PM10:1.13 (95% CI: 1.01–1.26) and 1.22 (1.06–1.41); NOx: 1.19 (1.07–1.33) and 1.13 (1.02–1.25) and BC: 1.12 (1.03–1.22) and 1.11 (1.02–1.21) per interquartile range increase in exposure. For total PM2.5 the positive associations of 1.12 (0.97–1.31) and 1.16 (0.98–1.36) were not significant. For baseline or lag 0 exposure there were significant associations only for NOx and BC, not for PM. Conclusion: Residential exposure to outdoor air pollution was associated with increased risk of incident CKD at relatively low exposure levels. Average long-term exposure was more clearly associated with CKD than current exposure or exposure at recruitment. Our findings imply that the health effects of low-level air pollution on CKD are considerable. © 2022
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| 5. |
- Xu, Yiyi, et al.
(författare)
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Associations of blood mercury and fatty acid concentrations with blood mitochondrial DNA copy number in the Seychelles Child Development Nutrition Study
- 2019
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 124, s. 278-283
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Tidskriftsartikel (refereegranskat)abstract
- Background: Fish contains methylmercury (MeHg) which can cause oxidative stress and neurodevelopmental toxicity at sufficiently high doses. Fish also contains polyunsaturated fatty acids (PUFA) which have both antioxidant (n-3) and oxidant (n-6) properties. Mitochondrial DNA (mtDNA) is sensitive to oxidative stress but has not been previously studied in relation to MeHg exposure or PUFA status. Objective: To investigate the associations between MeHg exposure and PUFA status during pregnancy with relative mitochondrial DNA copy number (RmtDNAcn) in mothers and their newborns. Methods: In total, 1488 mother-child pairs from the Seychelles Child Development Study Nutrition Cohort 2 were included in this study. Total Hg was measured in maternal blood collected at 28 weeks' gestation, maternal hair at delivery, and in fetal cord blood. PUFA (n-3 and n-6) were measured only in maternal blood. RmtDNAcn was measured by qPCR in both maternal and cord blood. Results: Increasing maternal blood Hg (beta = 0.001, 95% CI: 0.000, 0.002) and n-3 PUFA concentrations (beta = 0.183, 95% CI: 0.048, 0.317) were associated with higher maternal RmtDNAcn. Increasing maternal n-6 PUFA (beta =-0.103, 95% CI: -0.145, -0.062) and n-6/n-3 ratio (beta =-0.011, 95% CI: -0.017, -0.004) were associated with lower maternal RmtDNAcn. Increasing fetal cord blood Hg was associated with lower fetal RmtDNAcn (beta =-0.002, 95% CI: -0.004, -0.000). Neither maternal blood Hg nor PUFA status was associated with fetal RmtDNAcn. Conclusions: Our findings suggest that MeHg and PUFA may influence mitochondrial homeostasis although the magnitude of these associations are small. Future studies should confirm the findings and explore the underlying mechanisms.
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| 6. |
- Xu, Yiyi, et al.
(författare)
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Serum perfluoroalkyl substances in residents following long-term drinking water contamination from firefighting foam in Ronneby, Sweden.
- 2021
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Ingår i: Environment international. - : Elsevier BV. - 1873-6750 .- 0160-4120. ; 147
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Tidskriftsartikel (refereegranskat)abstract
- In December 2013, it was discovered that drinking water supplied to one third of the households in Ronneby, southern Sweden, was highly contaminated by PFAS (sum level >10,000ng/L) originated from firefighting foams used at a nearby military airport.To report serum PFAS levels of Ronneby residents participating in a biomonitoring program, and to describe the variation by age, sex and calendar period for residential exposure. In addition, a reference group living in a neighboring municipality without PFAS contaminated drinking water was examined.Blood samples and demographic data were collected for 3297 Ronneby residents and 226 individuals from the reference group. Yearly residence addresses were available for 3086 Ronneby residents from the national population registry. Serum concentrations of PFHxS, PFOS and PFOA were determined in all participants, with additional PFHpA, PFNA and PFDA in subsets of the participants.The population geometric means for serum PFHxS, PFOS and PFOA were 114, 135 and 6.8ng/mL for all Ronneby residents, i.e.135, 35 and 4.5 times higher than for the reference group. Ronneby residents who resided in the area with contaminated water supply during 2005-2013 showed much higher PFAS levels in 2014 than those exposed only before 2005. Ronneby residents who never resided in the area with contaminated water supply also had higher serum PFAS levels than the reference group. All three PFAS were highly correlated (rs>0.9 for each pair). Serum PFAS levels were lowest in teenage years and then increased with age. Adult females had lower PFAS levels on average than males under the age of 60 but higher above 60.The results reveal high serum PFAS levels dominated by PFHxS and PFOS in the Ronneby residents highly exposed to PFAS originated from firefighting foams. The PFAS exposure in Ronneby permits studies of associations to a range of health parameters, as well as studies of the toxicokinetics of PFAS exposure.
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| 7. |
- Xu, Yiyi, et al.
(författare)
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Associations between serum concentrations of perfluoroalkyl substances and DNA methylation in women exposed through drinking water: A pilot study in Ronneby, Sweden
- 2020
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Ingår i: Environment International. - : Elsevier BV. - 0160-4120. ; 145
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Tidskriftsartikel (refereegranskat)abstract
- Background: Perfluoroalkyl substances (PFAS) are widespread synthetic substances with various adverse health effects. A potential mechanism of toxicity for PFAS is via epigenetic changes, such as DNA methylation. However, few studies have evaluated associations between PFAS exposure and DNA methylation among adults, and data is especially scarce for women. Furthermore, exposure to environmental pollutants has been associated with epigenetic age acceleration, but no studies have yet evaluated whether PFAS is associated with epigenetic age acceleration. Objectives: To investigate whether exposure to PFAS is associated with alteration of DNA methylation and epigenetic age acceleration among women. Methods: In this observational pilot study, 59 women (aged 20-47 years at enrollment in 2014) from Ronneby, Sweden, an area with historically high PFAS exposure due to local drinking water contamination, were divided into three PFAS exposure groups (low, medium, and high). Genome-wide methylation of whole-blood DNA was analyzed using the Infinium MethylationEPIC BeadChip. Ingenuity Pathway Analysis was used for in silico functional assessment. Epigenetic age acceleration was derived from the DNA methylation data using Horvath's epigenetic skin and blood clock. Results: 117 differentially methylated positions (q < 0.017) and one near-significantly differentially methylated region (S100A13, FWER = 0.020) were identified. In silico functional analyses suggested that genes with altered DNA methylation (q < 0.05) were annotated to cancer, endocrine system disorders, reproductive system disease, as well as pathways such as estrogen receptor signaling, cardiac hypertrophy signaling, PPARa/RXRa activation and telomerase signaling. No differences in epigenetic age acceleration between PFAS exposure groups were noted (p = 0.43). Conclusion: The data suggests that PFAS exposure alters DNA methylation in women highly exposed to PFAS from drinking water. The observed associations should be verified in larger cohorts, and it should also be further investigated whether these changes in methylation also underlie potential phenotypic changes and/or adverse health effects of PFAS.
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