| 1. |
- Alhamdow, Ayman, et al.
(author)
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Cancer-related proteins in serum are altered in workers occupationally exposed to polycyclic aromatic hydrocarbons : a cross-sectional study
- 2019
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In: Carcinogenesis. - : Oxford University Press (OUP). - 0143-3334 .- 1460-2180. ; 40:6, s. 771-781
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Journal article (peer-reviewed)abstract
- Exposure to some polycyclic aromatic hydrocarbons (PAH) increases the risk of cancer and is common, particularly for workers in occupations such as chimney sweeping. In exposed workers, screening of early cancer-related markers provides important information to identify individuals at risk. Here, we aimed to elucidate the associations between PAH exposure and serum levels of cancer-related proteins in 118 chimney sweeps and 126 occupationally unexposed controls, all non-smoking males from Sweden. Monoydroxylated metabolites of pyrene, phenanthrene, benzo[a]pyrene, and benzo[a]anthracene were measured in urine using LC/MS/MS and 90 cancer-related proteins were measured in serum using a Proximity Extension Assay. Linear regression analysis adjusted for age, BMI, and false discovery rate (FDR) identified 17 serum proteins that were differentially expressed (16 upregulated and 1 downregulated) in chimney sweeps compared with controls (FDR<0.05). Concentrations of the peptidase kallikrein 13 (KLK13) showed significant positive associations with urinary concentrations of the PAH metabolites 3-hydroxybenzo[a]pyrene (B, 95%CI: 0.042, 0.008-0.076) and 3-hydroxybenzo[a]anthracene (B, 95%CI: 0.068, 0.002-0.134). Moreover, dose-response relationships were observed between KLK13 and 3-hydroxybenzo[a]pyrene (trend test P=0.027) and 3-hydroxybenzo[a]anthracene (P=0.035). Pathway and gene ontology analyses showed that cell movement, cell adhesion, and cell migration were the predominant molecular functions associated with the top differentially expressed proteins. In conclusion, we found a number of putative cancer-related proteins differentially expressed in workers exposed to PAH. This warrants effective measure to reduce PAH exposure among workers as well as further investigation to confirm these findings.
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| 2. |
- Alhamdow, Ayman, et al.
(author)
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Cardiovascular Disease-Related Serum Proteins in Workers Occupationally Exposed to Polycyclic Aromatic Hydrocarbons
- 2019
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In: Toxicological Sciences. - : Oxford University Press (OUP). - 1096-6080 .- 1096-0929. ; 171:1, s. 235-246
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Journal article (peer-reviewed)abstract
- Chimney sweeps have higher incidence and mortality of cardiovascular disease (CVD), likely related to their exposure to polycyclic aromatic hydrocarbons (PAH). In order to identify underlying mechanisms of PAH-related CVD, we here investigated whether PAH exposure was associated with levels of putative CVD-related proteins in serum among currently working chimney sweeps. We enrolled 116 chimney sweeps and 125 unexposed controls, all nonsmoking male workers from Sweden. We measured monohydroxylated PAH metabolites in urine by liquid chromatography coupled to tandem mass spectrometry and a panel of 85 proteins in serum using proximity extension assay. Linear regression analysis adjusted for age and body mass index showed that 25 proteins were differentially expressed between chimney sweeps and the controls (p <. 05, adjusted for false discovery rate). Of the 25 proteins, follistatin (FS), prointerleukin-16 (IL-16), and heat shock protein beta-1 (HSP 27) showed positive associations with the monohydroxylated metabolites of PAH in a dose-response manner (p <. 05). Pathway and gene ontology analyses demonstrated that the differentially expressed proteins were mainly involved in inflammatory response and immunological functions, such as leukocyte migration, cell movement of leukocytes, and adhesion of immune cells. In conclusion, we found a number of putative CVD-related proteins differentially expressed, between PAH-exposed and unexposed individuals, and mainly involved in inflammation and immune function. Our data warrant protective measures to reduce PAH exposure and longitudinal investigations of the protein profile in chimney sweeps and other occupational groups exposed to PAH.
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| 3. |
- Alhamdow, Ayman, et al.
(author)
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Chimney sweeps in Sweden : a questionnaire-based assessment of long-term changes in work conditions, and current eye and airway symptoms
- 2017
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In: International Archives of Occupational and Environmental Health. - : Springer Science and Business Media LLC. - 0340-0131 .- 1432-1246. ; 90:2, s. 207-216
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Journal article (peer-reviewed)abstract
- Objectives: To explore chimney sweeping work tasks, chimney sweeps’ use of protective equipment, and type of fuel used by clients, over time. Further, to assess work-relatedness of current eye and airway symptoms. Methods: In a cross-sectional study in 2011, male Swedish chimney sweeps (n = 483; age 21–69 years) answered a questionnaire about their occupational history and eye and airway symptoms. Results: Between 1960 and 2010, black-soot-sweeping in private homes was the major task, although it decreased during the time period, for chimney sweeps. Between 1975 and 2010, the use of petroleum oil decreased, whereas the use of pellets and wood increased. Also, the use of gloves and masks increased significantly. Black-soot-sweeping in industry was associated with work-related eye symptoms (prevalence odds ratio POR = 3.76, 95% CI: 1.72–8.24, for every 10% increment of working time, adjusted for age and tobacco smoking). Chimney sweeps also had slightly higher prevalence of cough with increasing black-soot-sweeping (POR = 1.06, 95% CI: 0.99–1.13 for every 10% increment, further adjusted for the use of mask), and the association was more pronounced, although nonsignificant, for black-soot-sweeping in industry (adjusted POR = 1.26, 95% CI: 0.98–1.61). Conclusions: Chimney sweeping tasks and use of protective equipment as well as type of fuel used by the clients changed significantly over the last 35 years, which may have changed chimney sweeps’ exposure to soot. Still, chimney sweeps in Sweden have black-soot-sweeping-related eye and airway symptoms.
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| 4. |
- Alhamdow, Ayman, et al.
(author)
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DNA-methylation of the cancer-related genes F2RL3 and AHRR is associated with occupational exposure to polycyclic aromatic hydrocarbons
- 2018
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In: Carcinogenesis. - : Oxford University Press. - 0143-3334 .- 1460-2180. ; 39:7, s. 869-878
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Journal article (peer-reviewed)abstract
- Some polycyclic aromatic hydrocarbons (PAH) are known carcinogens and workplace PAH exposure may increase the risk of cancer. Monitoring early cancer-related changes can indicate whether the exposure is carcinogenic. Here, we enrolled 151 chimney sweeps, 152 controls, and 19 creosote-exposed male workers from Sweden. We measured urinary PAH metabolites using LC/MS/MS, the cancer-related markers telomere length (TL) and mitochondrial DNA copy number (mtDNAcn) using qPCR, and DNA methylation of lung cancer-related genes F2RL3 and AHRR using pyrosequencing. The median 1-hydroxypyrene (PAH metabolite) concentrations were highest in creosote-exposed workers (8.0 μg/g creatinine) followed by chimney sweeps (0.34 μg/g creatinine) and controls (0.05 μg/g creatinine). TL and mtDNAcn did not differ between study groups. Chimney sweeps and creosote-exposed workers had significantly lower methylation of AHRR CpG site cg05575921 (88.1% and 84.9%, respectively) than controls (90%). Creosote-exposed workers (73.3%), but not chimney sweeps (76.6%) had lower methylation of F2RL3 cg03636183 than controls (76.7%). Linear regression analyses showed that chimney sweeps had lower AHRR cg05575921 methylation (B=-2.04; P<0.057, adjusted for smoking and age) and lower average AHRR methylation (B=-2.05; P<0.035), and non-smoking chimney sweeps had lower average F2RL3 methylation (B=-0.81; P<0.042, adjusted for age) compared with controls. These cancer-related markers were not associated with urinary concentrations of PAH metabolites. In conclusion, although we found no associations with PAH metabolites in urine (short-term exposure), our results suggest dose-response relationship between PAH exposure and DNA hypomethylation of lung cancer-related loci. These findings indicate that further protective measures should be taken to reduce PAH exposure.
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| 5. |
- Alhamdow, Ayman, et al.
(author)
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Early markers of cardiovascular disease are associated with occupational exposure to polycyclic aromatic hydrocarbons
- 2017
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In: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 7:1
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Journal article (peer-reviewed)abstract
- Occupational exposure to soot, rich in polycyclic aromatic hydrocarbons (PAH), has been associated with increased risk of cardiovascular disease (CVD). However, our knowledge about PAH exposure and early markers of CVD remains limited. In this cross-sectional study of 151 chimney sweeps and 152 controls, we investigated occupational exposure to PAH and early markers of CVD. Blood pressure (BP) (chimney sweeps only), urinary PAH metabolites and serum biomarkers were measured (C-reactive protein, homocysteine, gamma-glutamyltransferase, cholesterol, HDL, LDL, and triglycerides). Chimney sweeps had up to 7 times higher concentrations of PAH metabolites in urine than controls (P < 0.001): Median concentrations (adjusted for specific gravity) for 1-hydroxypyrene, 2-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, and 3-hydroxybenzo[a]anthracene were 0.56 μg/L, 0.78 μg/L, 4.75 ng/L, and 6.28 ng/L, respectively. Compared with controls, chimney sweeps had increased homocysteine, cholesterol, and HDL (β = 3.4 μmol/L, 0.43 mmol/L, and 0.13 mmol/L, respectively, P ≤ 0.003, adjusted for age, BMI, and smoking). In chimney sweeps, PAH metabolites correlated positively with the percentage of soot sweeping (P < 0.001). 2-hydroxyphenanthrene, 3-hydroxybenzo[a]pyrene, and 3-hydroxybenzo[a]anthracene were positively associated with diastolic BP (P < 0.044, adjusted for age, BMI, and smoking). PAH exposure among chimney sweeps resulted in elevated levels of markers for CVD risk. These findings stress the need to reduce occupational exposure to PAH.
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| 6. |
- Alhamdow, Ayman, et al.
(author)
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Fluorene exposure among PAH-exposed workers is associated with epigenetic markers related to lung cancer
- 2020
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In: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 77:7, s. 488-495
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Journal article (peer-reviewed)abstract
- Objectives Exposure to high-molecular-weight polycyclic aromatic hydrocarbons (PAHs) may cause cancer in chimney sweeps and creosote-exposed workers, however, knowledge about exposure to low-molecular-weight PAHs in relation to cancer risk is limited. In this study, we aimed to investigate occupational exposure to the low-molecular-weight PAHs phenanthrene and fluorene in relation to different cancer biomarkers. Methods We recruited 151 chimney sweeps, 19 creosote-exposed workers and 152 unexposed workers (controls), all men. We measured monohydroxylated metabolites of phenanthrene and fluorene in urine using liquid chromatography coupled to tandem mass spectrometry. We measured, in peripheral blood, the cancer biomarkers telomere length and mitochondrial DNA copy number using quantitative PCR; and DNA methylation ofF2RL3andAHRRusing pyrosequencing. Results Median PAH metabolite concentrations were higher among chimney sweeps (up to 3 times) and creosote-exposed workers (up to 353 times), compared with controls (p<0.001; adjusted for age and smoking). n-ary sumation OH-fluorene (sum of 2-hydroxyfluorene and 3-hydroxyfluorene) showed inverse associations with percentage DNA methylation ofF2RL3andAHRRin chimney sweeps (B (95% CI)=-2.7 (-3.9 to -1.5) forF2RL3_cg03636183, and -7.1 (-9.6 to -4.7) forAHRR_cg05575921: adjusted for age and smoking), but not in creosote-exposed workers. In addition, n-ary sumation OH-fluorene showed a 42% mediation effect on the inverse association between being a chimney sweep and DNA methylation ofAHRRCpG2. Conclusions Chimney sweeps and creosote-exposed workers were occupationally exposed to low-molecular-weight PAHs. Increasing fluorene exposure, among chimney sweeps, was associated with lower DNA methylation ofF2RL3andAHRR, markers for increased lung cancer risk. These findings warrant further investigation of fluorene exposure and toxicity.
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| 7. |
- Alhamdow, Ayman, et al.
(author)
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Low-level exposure to polycyclic aromatic hydrocarbons is associated with reduced lung function among Swedish young adults
- 2021
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In: Environmental Research. - : Elsevier BV. - 0013-9351 .- 1096-0953. ; 197
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Journal article (peer-reviewed)abstract
- Background: Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to adverse pulmonary effects. However, the impact of low-level environmental PAH exposure on lung function in early adulthood remains uncertain. Objectives: To evaluate the associations between urinary PAH metabolites and lung function parameters in young adults. Methods: Urinary metabolites of pyrene, phenanthrene, and fluorene were analysed in 1000 young adults from Sweden (age 22–25 years) using LC-MS/MS. Lung function and eosinophilic airway inflammation were measured by spirometry and exhaled nitric oxide fraction (FeNO), respectively. Linear regression analysis was used to evaluate associations between PAH metabolites and the outcomes. Results: Median urinary concentrations of 1-OH-pyrene, ∑OH-phenanthrene, and ∑OH-fluorene were 0.066, 0.36, 0.22 μg/L, respectively. We found inverse associations of ∑OH-phenanthrene and ∑OH-fluorene with FEV1 and FVC, as well as between 1-OH-pyrene and FEV1/FVC ratio (adjusted P < 0.05; all participants). An increase of 1% in ∑OH-fluorene was associated with a decrease of 73 mL in FEV1 and 59 mL in FVC. In addition, ∑OH-phenanthrene concentrations were, in a dose-response manner, inversely associated with FEV1 (B from −109 to −48 compared with the lowest quartile of ∑OH-phenanthrene; p trend 0.004) and FVC (B from −159 to −102 compared with lowest quartile; p-trend <0.001). Similar dose-response associations were also observed between ∑OH-fluorene and FEV1 and FVC, as well as between 1-OH-pyrene and FEV1/FVC (p-trend <0.05). There was no association between PAH exposure and FeNO, nor was there an interaction with smoking, sex, or asthma. Conclusion: Low-level PAH exposure was, in a dose-response manner, associated with reduced lung function in young adults. Our findings have public health implications due to i) the widespread occurrence of PAHs in the environment and ii) the clinical relevance of lung function in predicting all-cause and cardiovascular disease mortality.
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| 8. |
- Alhamdow, Ayman
(author)
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Occupational exposure to polycyclic aromatic hydrocarbons and early biomarkers related to cardiovascular disease and cancer
- 2019
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Doctoral thesis (other academic/artistic)abstract
- Polycyclic aromatic hydrocarbons (PAH) are omnipresent environmental pollutants composed of fused benzene rings and mainly produced by incomplete combustion of organic material. PAH exposure has been associated with increased risk of cancer and probably cardiovascular disease (CVD). In one way or another, everyone is exposed to PAH, but the dose and the period of exposure vary between individuals. Workers who remove soot from chimneys (chimney sweeps) are likely exposed to higher levels of PAH compared with the general population. However, whether the current PAH exposure among chimney sweeps leads to disease is not known. The overall aim of this thesis was to evaluate PAH exposure among currently working chimney sweeps as well as explore early biomarkers related to cardiovascular disease (CVD) and cancer. For this purpose, we recruited 151 chimney sweeps and 152 unexposed control individuals, all males from southern Sweden, from whom we collected questionnaires and biological samples. In one of the studies, we additionally used data and biological samples from 19 creosote-exposed workers, i.e. workers who impregnate wood panels with black oily material rich in PAH known as creosote. We found that PAH exposure (measured as PAH metabolites in urine) was up to 7 times higher among chimney sweeps compared with unexposed control workers, and the levels of PAH metabolites were positively associated with diastolic blood pressure. Moreover, we found higher serum concentrations of the classical risk markers for CVD (homocysteine and cholesterol) in chimney sweeps, compared with controls. Further, we found 25 putative CVD-related serum proteins differentially expressed between nonsmoking chimney sweeps and controls, among which follistatin (FS), heat shock protein beta-1 (HSP 27), and pro-interleukin-16 (IL-16) showed positive dose-response relationships with PAH metabolites. Pathway analysis demonstrated that these 25 proteins were mainly involved in inflammatory response and immune function. We also demonstrated hypomethylation (lower methylation) of the genes F2RL3 and AHRR, risk markers for lung cancer, among chimney sweeps and creosote-exposed workers, compared with controls. Notably, creosote-exposed workers had the highest PAH exposure and the lowest DNA methylation, compared with both chimney sweeps and controls, which suggests a dose-response relationship. In addition, we found 17 putative cancer-related serum proteins differentially expressed between nonsmoking chimney sweeps and controls, among which kallikrein-13 (KLK13) showed positive dose-response relationships with the metabolites of carcinogenic PAH (BaP and BaA). Pathway analysis showed that most of the differentially expressed proteins were involved in cell movement, cell migration, and cell invasion. Overall, findings from this thesis indicate that (i) currently working chimney sweeps are markedly exposed to PAH, (ii) chimney sweeps showed molecular changes related to CVD and cancer, and (iii) some of these molecular changes seem to be, at least partly, induced by PAH exposure. These results stress that protective measures are warranted to reduce PAH exposure among chimney sweeps as well as other occupational groups at risk of PAH exposure. In addition, further research exploring mechanisms of PAH-induced CVD and cancer is encouraged in order to develop strategies of early detection of disease among individuals known to be exposed to PAH.
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| 9. |
- Dauter, Ulrike Maria, et al.
(author)
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Cancer-related changes and low-to-moderate exposure to welding fumes : A longitudinal study
- 2022
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In: Scandinavian Journal of Work, Environment and Health. - : Scandinavian Journal of Work, Environment and Health. - 0355-3140 .- 1795-990X. ; 48:1, s. 21-30
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Journal article (peer-reviewed)abstract
- Objective This study tested for an association between early cancer-related biomarkers and low-to-moderate exposure to fumes from welding mild steel.Methods Male, non-smoking participants from southern Sweden were recruited and examined (N=338, 171 welders and 167 controls); of these, 78 welders and 96 controls were examined on two occasions six years apart. Exposure to welding fumes was evaluated by measuring respirable dust, welding years, and cumulative exposure. DNA methylation of CpG sites within the cancer-related genes AHRR, F2RL3, and B3GNTL1 was measured by pyrosequencing and relative mitochondrial DNA copy number and telomere length were measured by qPCR in whole-blood samples. Multivariate models were used for longitudinal analysis.Results Median exposure to respirable dust was 0.7 mg/m3 at both timepoints, adjusted for use of personal protective equipment. Compared with controls, welders showed a significant decrease over time in DNA methylation of B3GNTL1 CpG1 and CpG4 [adjusted for age, body mass index, and smoking: β=-0.66, standard error (SE)=0.28; β=-0.48, SE=0.24, respectively]. In addition, exposure to respirable dust and cumulative exposure was associated with a decrease in methylation of F2RL3 CpG2 among all welders (adjusted β=-0.67, SE=0.23 and β=-0.03, SE=0.02, respectively). No significant associations were found for AHRR, mitochondrial DNA copy number, or telomere length.Conclusion Low-to-moderate exposure to welding fumes was associated with a small effect on selected early epigenetic biomarkers of cancer. The direction of the methylation pattern (lower methylation of specific CpG sites) indicates early lung cancer-related changes associated with mild steel welding.
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| 10. |
- Engström, Karin, et al.
(author)
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Polymorphisms in ATP-binding cassette transporters associated with maternal methylmercury disposition and infant neurodevelopment in mother-infant pairs in the Seychelles Child Development Study
- 2016
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In: Environment International. - : Elsevier BV. - 0160-4120 .- 1873-6750. ; 94, s. 224-229
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Journal article (peer-reviewed)abstract
- Background: ATP-binding cassette (ABC) transporters have been associated with methylmercury (MeHg) toxicity in experimental animal models. Aims: To evaluate the association of single nucleotide polymorphisms (SNPs) in maternal ABC transporter genes with 1) maternal hair MeHg concentrations during pregnancy and 2) child neurodevelopmental outcomes. Materials and methods: Nutrition Cohort 2 (NC2) is an observational mother-child cohort recruited in the Republic of Seychelles from 2008-2011. Total mercury (Hg) was measured in maternal hair growing during pregnancy as a biomarker for prenatal MeHg exposure (N = 1313) (mean 3.9 ppm). Infants completed developmental assessments by Bayley Scales of Infant Development II (BSID-II) at 20 months of age (N = 1331). Genotyping for fifteen SNPs in ABCC1, ABCC2 and ABCB1 was performed for the mothers. Results: Seven of fifteen ABC SNPs (ABCC1 rs11075290, rs212093, and rs215088; ABCC2 rs717620; ABCB1 rs10276499, rs1202169, and rs2032582) were associated with concentrations of maternal hair Hg (p < 0.001 to 0.013). One SNP (ABCC1 rs11075290) was also significantly associated with neurodevelopment; children born to mothers with rs11075290 CC genotype (mean hair Hg 3.6 ppm) scored on average 2 points lower on the Mental Development Index (MDI) and 3 points lower on the Psychomotor Development Index (PDI) than children born to mothers with TT genotype (mean hair Hg 4.7 ppm) while children with the CT genotype (mean hair Hg 4.0 ppm) had intermediate BSID scores. Discussion: Genetic variation in ABC transporter genes was associated with maternal hair Hg concentrations. The implications for MeHg dose in the developing child and neurodevelopmental outcomes need to be further investigated.
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