Urinary Polycyclic Aromatic Hydrocarbons Metabolites Research Articles

Firefighters’ absorption of PAHs and VOCs during controlled residential fires by job assignment and fire attack tactic

To better understand the absorption of combustion byproducts during firefighting, we performed biological monitoring (breath and urine) on firefighters who responded to controlled residential fires and examined the results by job assignment and fire attack tactic. Urine was analyzed for metabolites of polycyclic aromatic hydrocarbons (PAHs) and breath was analyzed for volatile organic compounds (VOCs) including benzene. Median concentrations of PAH metabolites in urine increased from pre-firefighting to 3-h post firefighting for all job assignments. This change was greatest for firefighters assigned to attack and search with 2.3, 5.6, 3.9, and 1.4-fold median increases in pyrene, phenanthrene, naphthalene, and fluorene metabolites. Median exhaled breath concentrations of benzene increased 2-fold for attack and search firefighters (p < 0.01) and 1.4-fold for outside vent firefighters (p = 0.02). Compared to interior attack, transitional attack resulted in 50% less uptake of pyrene (p = 0.09), 36% less uptake phenanthrene (p = 0.052), and 20% less uptake of fluorene (p < 0.01). Dermal absorption likely contributed to firefighters’ exposures in this study. Firefighters’ exposures will vary by job assignment and can be reduced by employing a transitional fire attack when feasible.

Combined effect of central obesity and urinary PAH metabolites on lung function: A cross-sectional study in urban adults.

Central obesity and polycyclic aromatic hydrocarbons (PAHs) exposure were reported as independent risk factors for lung function decline. However, the interaction between central obesity and PAHs exposure on lung function is still unclear. To evaluate the impact of central obesity, urinary polycyclic aromatic hydrocarbon metabolites (OH-PAHs) and their combined effects on lung function in general population. Lung function and urinary OH-PAHs were measured for 3,749 participants from the Wuhan-Zhuhai cohort. Central obesity was evaluated by waist-to-hip ratio. Generalized linear regression was used to estimate combined effect of central obesity and OH-PAHs on lung function. Compared with participants without central obesity and with low urinary total OH-PAHs (∑OH-PAHs) level, those with central obesity and high urinary ∑OH-PAHs level had 59.4 mL and 61.0 mL reductions for forced vital capacity (FVC) and forced expiratory volume in 1s (FEV1), respectively (P < 0.05). The reductions were more evident in smokers and males. Additive interactions between central obesity and urinary ∑OH-PAHs on lung function were observed, especially on FEV1 (P < 0.05). Each 1-unit increase in log-transformed value of ∑OH-PAHs was associated with -34.4 ml (95% confidence interval [CI]: -66.9, -1.8) and -34.8 mL (-61.1, -8.5) changes in FVC and FEV1 among those without central obesity, while -21.4 ml (-49.9, 7.1) and -19.7 ml (-43.4, 4.0) changes among those with central obesity. Polycyclic aromatic hydrocarbons exposure has combined effect with central obesity on lung function parameters.

Prenatal polycyclic aromatic hydrocarbons metabolites, cord blood telomere length, and neonatal neurobehavioral development

BackgroundPrenatal exposure to polycyclic aromatic hydrocarbon (PAH) is a potential risk factor for child neurobehavioral development. Telomere length (TL) has important implications for health over the life course. ObjectiveIn this study, we aimed to investigate whether prenatal urinary PAH metabolites were associated with adverse neonatal neurobehavioral development and altered cord blood TL and to explore whether the change of TL was a predictor of neonatal neurobehavioral development. MethodWe enrolled 283 nonsmoking pregnant women in Taiyuan city. Eleven PAH metabolites were measured in maternal urine samples. TL in cord blood was measured by real time quantitative polymerase chain reaction. Neonatal behavioral neurological assessment (NBNA) tests were conducted when the infants were three days old. Multiple linear regression models were used to analyze the associations of maternal urinary PAH metabolites with NBNA scores and cord blood TL, and restricted cubic spline models were further used to examine the shapes of dose-response relationships. A mediation analysis was also conducted. ResultWe observed dose-response associations of maternal urinary 2-hydroxyfluorene (2-OHFlu) and 2-hydroxyphenanthrene (2-OH Phe) with decreased active tone scores, sum of NBNA scores, and cord blood TL (P for trend<0.05). Each 1 unit increase in urinary levels of Ln (2-OH Flu) or Ln (2-OH Phe) was associated with a 0.092 or 0.135 decrease in the active tone scores and a 0.174 or 0.199 decrease in the sum of NBNA scores. Mediation analysis showed TL could explained 21.74% of the effect of sum of NBNA scores change related to prenatal exposure to 2-OH Phe (P for mediator = 0.047). ConclusionOur data indicates maternal urinary specific PAH metabolites are inversely associated with neonatal neurobehavioral development and cord blood TL. TL mediates the associations of 2-OH Phe with neonatal neurobehavioral development and partly explains the effect of 2-OH Phe on neonatal neurobehavioral development.

Heart rate variability mediates the association between polycyclic aromatic hydrocarbons exposure and atherosclerotic cardiovascular disease risk in coke oven workers

Polycyclic aromatic hydrocarbons (PAHs) metabolites was related to heart rate variability (HRV) reduction and atherosclerotic cardiovascular disease (ASCVD), and ASCVD was also affected by HRV. However, the mediating role of HRV in the association between PAHs exposure and ASCVD risk was largely unknown. We aimed to investigate whether the relation of PAHs exposure with ASCVD risk was mediated by HRV among coke oven workers. A total of 1100 subjects with complete data were qualified in the current study. We measured 12 urinary PAHs metabolites by gas chromatography-mass spectrometry (GC-MS) and HRV indices by 3-channel digital Holter monitors. The associations between urinary PAHs metabolites, HRV indices, and ASCVD risk were explored using generalized linear models or multivariate logistic regression models. A mediation analysis was conducted to examine the role of HRV on the association between PAHs exposure and ASCVD risk. We found that urinary 1-hydroxynaphthalene (1-OHNa), 2-OHNa, and total PAH metabolites (ΣOH-PAH) were dose-responsive associated with increased risk of ASCVD. Compared with lowest quartile, the adjusted odds ratio (OR) for ASCVD risk in the highest quartile were 2.36 for 1-OHNa, 6.58 for 2-OHNa, and 1.60 for ΣOH-PAH (all Ptrend<0.05). In addition, significant dose-dependent relationships were found across 2-OHNa quartiles with decreasing HRV indices, which in turn, were positively associated with elevated risk of ASCVD (all Ptrend<0.05). Mediation analyses indicated that HRV mediate 2.7%–4.3% of the association between 2-OHNa exposure and higher ASCVD risk. Our data suggested that occupational exposure to PAHs may increase ASCVD risk, which was partially mediated by HRV.

OGG1 methylation mediated the effects of cell cycle and oxidative DNA damage related to PAHs exposure in Chinese coke oven workers

Previous publications have indicated that polycyclic aromatic hydrocarbons (PAHs) exposures are associated with increased DNA damage and abnormal cell cycle arrest; however, the details of mechanisms remain largely unknown. This study aimed to quantify the associations of 8-oxoguanine DNA glycosylase (OGG1) methylation with urinary PAHs metabolites, DNA damage and cell cycle arrest, and further to assess the role of OGG1 methylation in mediating the association of urinary PAHs metabolites with DNA damage and cell cycle arrest. Urinary biomarkers of PAHs exposure and a marker of oxidative DNA damage (8-hydroxy-2′-deoxyguanosin, 8-OHdG) were measured by high performance liquid chromatography. Cell cycle of lymphocyte was analysed with flow cytometry and OGG1 methylation in venous blood was measured by pyrosequencing. After adjusting for covariates, urinary 1-OHP levels were positively associated with lymphocyte S phase arrest and oxidative DNA damage, while were negatively associated with G0/G1 phase arrest. OGG1 methylation was not only positively correlated with urinary 1-OHP in a dose-responsive manner (P trend = 0.008) but was also associated with G0/G1 phase arrest (OR: 0.63, 95% CI: 0.41–0.97), S phase arrest (OR: 1.55, 95% CI: 1.01–2.40) and oxidative DNA damage (OR: 1.71, 95% CI: 1.02–2.86). Mediation analysis estimated that OGG1 methylation mediated about 20% of associations between urinary 1-OHP levels and cell cycle arrest and oxidative DNA damage, respectively (all P < 0.05). Our findings suggested that urinary 1-OHP concentrations were associated with cell cycle arrest and oxidative DNA damage by a mechanism partly involving OGG1 methylation.

Correction to "Urinary Polycyclic Aromatic Hydrocarbon Metabolite Associations with Biomarkers of Inflammation, Angiogenesis, and Oxidative Stress in Pregnant Women".

Environmental exposure to polycyclic aromatic hydrocarbons (PAHs) is prevalent and may adversely impact pregnancy and development of the fetus. The purpose of this exploratory study was to examine urinary PAH metabolites in potential association with mediators of these outcomes. To do so, we measured a panel of 12 inflammatory, angiogenic, and oxidative stress biomarkers in plasma or urine from women in their third trimester of pregnancy (n = 200). Urinary PAH metabolites were highly detectable (>88%) in the study population, and most were higher in women who had lower education levels, higher body mass index, and who were African-American. Some PAH metabolites showed consistent positive associations with the plasma inflammation marker C-reactive protein (CRP) and the urinary oxidative stress markers 8-hydroxydeoxyguanosine (8-OHdG) and 8-isoprostane. For example, an interquartile range increase in 2-hydroxynapthalene was associated with a 35% increase in CRP (95% confidence interval = −0.13, 83.2), a 14%...

Predictors of Urinary Polycyclic Aromatic Hydrocarbon Concentrations: NHANES 2001–2006

Polycyclic aromatic hydrocarbons (PAHs) are hazardous air pollutants formed during incomplete combustion, absorbed through inhalation and ingestion, and metabolized to hydroxylated compounds that can be detected in urine. Biomonitoring data provide a direct way to link human exposure to environmental contaminants. However, these data do not reveal how various exposure routes or media contribute to the body burden of a specific chemical. We evaluated predictors of urinary PAH concentrations in 2001–2006 NHANES participants from reported information on demographic and housing characteristics, reported food intake, and modeled outdoor air pollutant exposures. NHANES participants were linked to their daily PM2.5 exposure estimate and annual air toxics concentrations. Multivariate linear regression models were developed using the Deletion/Substitution/Addition algorithm to predict urinary PAHs. Exposure to air pollution was not associated with levels of urinary PAH metabolites. Current smoking status was the strongest predictor of PAH biomarker concentration and was able to explain 10–47% of the variability of PAH biomarker concentrations. In non-smokers, our prediction models were able to explain only 2–5% of the variability of PAH biomarker concentrations. Overall, our results indicated, with the exception of smoking status, there are not strong demographic, dietary, or environmental predictors of PAH exposure.

Cardiovascular endothelial inflammation by chronic coexposure to lead (Pb) and polycyclic aromatic hydrocarbons from preschool children in an e-waste recycling area

Lead (Pb) and polycyclic aromatic hydrocarbon (PAH) exposure is positively associated with cardiovascular disease (CVD), and the possible potential mechanism may be caused by damage to the endothelium by modulation of inflammatory processes. No comprehensive research shows co-exposure of Pb and PAH on cardiovascular endothelial inflammation in electronic waste (e-waste) exposed populations. Given this, the aim of this study is to provide evidence for a relationship between Pb and PAH co-exposure and cardiovascular endothelial inflammation, in an e-waste-exposed population, to delineate the link between a potential mechanism for CVD and environmental exposure. We recruited 203 preschool children (3–7 years) were enrolled from Guiyu (e-waste-exposed group, n = 105) and Haojiang (reference group, n = 98). Blood Pb levels and urinary PAH metabolites were measured. Percentages of T cells, CD4+ T cells and CD8+ T cells, complete blood counts, endothelial inflammation biomarker (serum S100A8/A9), and other inflammatory biomarkers [serum interleukin (IL)-6, IL-12p70, gamma interferon-inducible protein 10 (IP-10)] levels were evaluated. Blood Pb, total urinary hydroxylated PAH (ΣOHPAH), total hydroxynaphthalene (ΣOHNap) and total hydroxyfluorene (ΣOHFlu) levels, S100A8/A9, IL-6, IL-12p70 and IP-10 concentrations, absolute counts of monocytes, neutrophils, and leukocytes, as well as CD4+ T cell percentages were significantly higher in exposed children. Elevated blood Pb, urinary 2-hydroxynaphthalene (2-OHNap) and ΣOHFlu levels were associated with higher levels of IL-6, IL-12p70, IP-10, CD4+ T cell percentages, neutrophil and monocyte counts. Mediator models indicated that neutrophils exert the significant mediation effect on the relationship between blood Pb levels and S100A8/A9. IL-6 exerts a significant mediation effect on the relationship between blood Pb levels and IP-10, as well as the relationship between urinary ΣOHFlu levels and IP-10. Our results indicate that children with elevated exposure levels of Pb and PAHs have exacerbated vascular endothelial inflammation, which may indicate future CVD risk in e-waste recycling areas.

Maternal urinary 2-hydroxynaphthalene and birth outcomes in Taiyuan, China

BackgroundNaphthalene is the simplest polycyclic aromatic hydrocarbon (PAH). It is easily emitted into the atmosphere, posing a significant risk to human health. However, limited studies have described the impact of naphthalene exposure on birth outcomes. In this study, we investigated the association between the maternal urinary metabolites of naphthalene, 2-hydroxynaphthalene (2-OH NAP), and birth outcomes.MethodIn the present study, four urinary PAH metabolites were measured in 263 pregnant women during late pregnancy. Multiple linear regression analysis was used to analyze the relationship between the concentrations of 2-OH NAP and birth outcomes, and restricted cubic spline models were further used to examine the shapes of the dose-response association.ResultGeneral linear models showed that prenatal urinary 2-OH NAP was associated with lower birth weight (BW) (− 4.38% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.049) and higher cephalization index (CI) (4.30% for the high vs. low exposure group of 2-OH NAP; p for trend = 0.038). These associations were linear and significant when 2-OH NAP was modeled as a continuous variable in restricted cubic spline models (P linear = 0.0293 for 2-OH NAP and BW; P linear = 0.0326 for 2-OH NAP and CI). Multiple linear regression data indicated that each 1 ln-unit increase in 2-OH NAP was significantly associated with a 2.09 g/cm increase in the CI. The associations among 2-OH NAP, BW, and CI were also observed in a subset of participants residing close to arterial traffic.ConclusionOur data indicated that prenatal exposure to naphthalene had an adverse effect on fetal birth outcomes, especially the brain development index. Reduced exposure to naphthalene may improve newborn health outcomes. In Taiyuan, naphthalene may result from traffic pollution.

Maternal urinary metabolites of PAHs and its association with adverse birth outcomes in an intensive e-waste recycling area

Polycyclic aromatic hydrocarbons (PAHs) are well-known carcinogenic and endocrine disrupting chemicals that have been concerned over the past few decades. We aimed to determine the hydroxylated PAH (OHPAH) metabolite concentrations in maternal urine collected from the e-waste-contaminated area of Guiyu and the reference area of Haojiang, China, and to evaluate their health effects on birth outcomes. The median ƩOHPAH concentration was 6.87 μg/g creatinine from Guiyu, and 3.90 μg/g creatinine from Haojiang. 2-OHNap and 1-OHPyr were the predominant metabolites. Residence in Guiyu and recycling in houses were associated with elevated 2-OHNap and 1-OHPyr. Standardized mean difference revealed that compared to low PAH metabolite levels in the first quartile, high PAH metabolite levels in the fourth quartile especially for 1-OHPyr, ƩOHPAHs and sometimes hydroxylphenanthrene compounds, presented a reduced size in birth outcomes (overall SMD: −0.09; 95% CI: −0.15, −0.03), including head circumference, BMI and Apgar 1 score, and increased size in height. After adjusting for confounders in regression models, an interquartile increase in ΣOHPAHs was associated with a decrease of 234.56 g in weight (95% CI: −452.00, −17.13), 1.72 cm in head circumference (95% CI: −2.96, −0.48), 1.06 kg/m2 in BMI (95% CI: −1.82, −0.31) and 0.42 in Apgar 1 score (95% CI: −0.66, −0.18), respectively. These findings suggest high exposure to PAHs during pregnancy in e-waste areas, posing a potential threat to neonatal development, which likely can be attributed to direct e-waste recycling activities. Ongoing studies should be continued to monitor human exposure and health, in particular for vulnerable individuals in e-waste-polluted areas.

Association between urinary polycyclic aromatic hydrocarbon metabolites and dyslipidemias in the Chinese general population: A cross-sectional study

BackgroundExposure to polycyclic aromatic hydrocarbons (PAHs) has been associated with metabolic diseases. However, relationships between PAH exposures and dyslipidemias have not been well addressed. ObjectivesTo investigate associations between urinary PAH metabolite concentrations and dyslipidemias in the general population. MethodsTwelve urinary PAH metabolites and four serum lipid profiles were measured in 3640 Chinese adults from the Wuhan-Zhuhai cohort. Dyslipidemias, including hyper-total cholesterol (HyperTC), hyper-triglyceride (HyperTG), hyper-low density lipoprotein cholesterol (HyperLDL-C), and hypo-high density lipoprotein cholesterol (HypoHDL-C) were classified according to the levels of serum lipids. Multiple logistic regression models were used to estimate the associations between urinary PAH metabolites and the prevalence of dyslipidemias. The effects of PAH exposure routes on dyslipidemias were further estimated by stratified analysis. ResultsWe found positive exposure-response relationships between urinary PAH metabolites and the prevalence of dyslipidemias. Compared with the lowest tertile of urinary PAH metabolites, increased risk of HyperTC were observed in those in the highest tertiles; The odds ratios (ORs) and 95% confidence intervals were 1.23 (1.03, 1.47), 1.44 (1.21, 1.71), 1.19 (1.01, 1.42), and 1.43 (1.20, 1.71) for 1-OHNa, 9-OHFlu, 1-OHPh, and 4-OHPh, respectively. Participants in the highest tertiles of 1-OHNa and 2-OHFlu had higher risk for HyperLDL-C, and the ORs were 1.21 (1.01, 1.45) and 1.18 (0.98, 1.42), respectively. Among smokers, only urinary 1-OHNa was associated with increased risk of HyperTC (1.36, 1.08–1.73) and HyperLDL-C (1.33, 1.01–1.74). While the increasing urinary levels of 9-OHFlu, 1-OHPh, and 4-OHPh were significantly associated with increased risk of HyperTC among non-smokers. In addition, the associations between urinary PAH metabolites and dyslipidemias were more pronounced among non-smokers who are cooked for themselves and had long-term traffic exposure. ConclusionElevated urinary PAH metabolites were associated with increased risks of HyperTC and HyperLDL-C. The source of PAH exposure could modify PAH species that affect dyslipidemias.

Dose-response relationships between polycyclic aromatic hydrocarbons exposure and platelet indices

The relations of polycyclic aromatic hydrocarbons (PAHs) exposure with platelet indices remain unclear. Based on the baseline data from the Wuhan-Zhuhai Cohort Study, we used generalized linear model, multivariate logistic regression analysis and restricted cubic splines (RCS) to assess linear and nonlinear relationship of PAHs exposure with platelet indices. The results showed that among Wuhan individuals, there were the non-linear relations between total hydroxynaphthalene (ΣOHNa) and mean platelet volume (MPV) or ratio of mean platelet volume to platelet count (MPVP), total hydrophenanthrene (ΣOHPh) and MPV or platelet distribution width (PDW), the sum concentration of urinary monohydroxylated metabolites of PAHs (ΣOH-PAHs) and ratio of platelet count to lymphocyte count (PLR) or MPVP, 1-hydropyrene (1-OHP) and PLR or PDW. But among Zhuhai individuals, neither linear nor non-linear relations were found between each of OH-PAHs or ΣOH-PAHs and platelet indices. The findings indicate that serum MPV and MPVP may be independent biomarkers of effects of exposing to environmental PAHs on human bodies.

Latent class analysis of the association between polycyclic aromatic hydrocarbon exposures and body mass index

BackgroundPeople experience multiple co-occurring exposures to environmental pollutants, but analyses of multiple exposures have rarely been reported. ObjectivesWe used latent class analysis to estimate co-exposures to multiple polycyclic aromatic hydrocarbons (PAH), and tested the associations of latent classes to body mass index. MethodsWe analyzed National Health and Nutrition Examination Survey (NHANES) 2013–2014 data. The sample included 2354 people aged 6–80 years. Measures included seven urinary PAH metabolites, BMI, and demographic and behavioral covariates. People were classified into mutually exclusive latent classes characterized by unique profiles of multiple PAH exposures. These classes were used as categorical independent variables in weighted multiple regression models with BMI as the dependent measure. Models were analyzed overall and by age groups (6–19, 20–59, and 60 and over.) We compared results using latent classes to results using a summed PAH exposure measure. ResultsFive latent classes were identified. Two of these classes were significantly associated with higher BMI overall (p < .0001) and for the two youngest age groups. One of these classes was characterized by high multiple exposures across all PAHs, and one by moderate exposures but relatively high naphthalene and phenanthrene. The summed PAH score was associated with higher BMI only for the youngest age group. ConclusionsPersons experience multiple co-exposures to PAHs that are related to BMI and obesity across age groups. Latent class analysis provides information on higher order interactions among multiple chemicals that a summed score does not. Future work may apply this approach to other outcomes or types of co-exposures.

Association of PAHs and BTEX exposure with lung function and respiratory symptoms among a nonoccupational population near the coal chemical industry in Northern China

Emissions (particularly aromatic compounds) from coal industries and biomass fuels combustion lead to high health risks for neighboring residents. To investigate the association of polycyclic aromatic hydrocarbons (PAHs) and benzene, toluene, ethylbenzene and 1,2-dimethylbenzene (BTEX) exposure with lung function and respiratory symptoms among adults and children near the coal-chemical industry in Northern China, adults and children from a county dotted with coal chemical industry were chosen as subjects for investigation (investigated area, IR). The control group consisted of adults and children from an agricultural county (control area, CR). The environmental and urinary PAH and BTEX levels of adults and children were determined by isotope dilution liquid chromatography coupled with tandem mass spectrometry. The Mann-Whitney U test and multivariate linear regression models were used to analyze the relationship between pollutant exposure and the respiratory system. The results showed that in an ambient environment, levels of PAHs and BTEX in the IR were significantly higher than those in the CR. Particularly, the concentration profiles for air samples were IR > CR and indoor > outdoor. Both for adults and children, the geometric (GM) concentrations of urinary PAHs and BTEX from the IR were significantly higher than those measured in the CR. Additionally, the urinary PAH exposure level profiles of smokers were higher than those of nonsmokers, indicating that indoor air and smoking were both important nonoccupational exposure sources. The decline of the forced expiratory in the first second (FEV1, %) and the forced expiratory middle flow rate (FEF25%) in children were associated with increasing urinary PAH metabolite levels (p < 0.05). The increase in urinary 1-OHN, 3-OHPhe, 4-OHPhe and 1-OHP levels could be linked to a decrease in FEV1 (r = −0.179, p < 0.05) and FEF25% with the coefficient of −0.166, −0.201 and −0.175 (p < 0.05), respectively. Medical examinations and lung function tests indicated that residents in the IR had higher occurrences of chest inflammation or declining lung function than residents in the CR. Moreover, exposure to PAHs and BTEX could decrease child lung function, though decreased lung function was not observed in adults. Both urinary monitoring and lung function data showed that children were more sensitive to PAH and BTEX exposure than adults.

Cardiometabolic traits mediated the relationship from urinary polycyclic aromatic hydrocarbons metabolites to heart rate variability reduction: A community-based study

Polycyclic Aromatic Hydrocarbons (PAHs) exposure was related with metabolic syndrome (MetS) and heart rate variability (HRV) reduction, and HRV was also affected by cardiometabolic traits. However, the role of cardiometabolic traits in the associations from PAHs exposures to HRV was largely unknown. We conducted this study to investigate whether the relationship between PAHs exposure and HRV reduction was mediated by cardiometabolic traits. Levels of urinary polycyclic aromatic hydrocarbons metabolites (OH-PAHs), 10min-HRV, and metabolic traits were accurately measured for 2476 participants from Wuhan-Zhuhai (WHZH) cohort. Single mediator and multiple mediator models were used to evaluate the mediation effects of cadiometabolic traits. The concentrations of ΣOH-PAHs ranged from 4.20 to 8.63 mg/mmol Cr. When compared with the lowest tertile, ΣOH-PAHs in the highest tertile were significantly related with 20% (95% confidence interval [95%CI]:1%, 40%), 35% (95%CI: 14%, 56%), 22% (95%CI: 1%, 44%), and 38% (95%CI: 9%, 68%) decreases in very low frequency (VLF), low frequency (LF), high frequency (HF), and total power (TP) for participants with MetS, respectively. No statistically significant associations between ΣOH-PAHs and HRV indices were observed for participants without MetS. Similar results were found when we investigated the relationships between OH-PAHs and HRV indices by three groups of OH-PAHs (including total hydroxynaphthalene [ΣOHNa], total hydroxy fluorene [ΣOHFlu], and total hydroxyphenanthrene [ΣOHPh] metabolites). Further, mediation analysis suggested that cardiometabolic traits, including fasting glucose (GLU), high density lipoprotein (HDL), and blood pressure partially mediated the relationship from ΣOH-PAHs to HRV reduction. GLU was the strongest mediator, with mediation percentages of 15.70% for VLF, 14.70% for LF, 43.03% for HF, and 5.61% for TP. Our study found that the relationships between OH-PAHs and HRV reduction differed among participants with and without MetS, and these relationships were found to be partially mediated by cardiometabolic traits, especially fasting glucose. Further studies are encouraged to validate our findings and investigate potential mechanisms.

The interaction effects of polycyclic aromatic hydrocarbons exposure and TERT- CLPTM1L variants on longitudinal telomere length shortening: A prospective cohort study

Telomere length (TL) is an index of cellular aging and can predict the incidences of many age-related diseases. Change of TL might be affected by environmental pollution and individual's genetic background. In this cohort study, we aimed to evaluate the associations between polycyclic aromatic hydrocarbons (PAHs) exposure and longitudinal TL shortening, and investigate whether genetic variations in TERT-CLPTM1L can modify these associations. We measured the baseline concentrations of twelve urinary PAH metabolites and genotyped six variants at TERT-CLPTM1L among 1243 coke-oven workers. The relative leukocyte TL was detected in both baseline and follow-up (4 years later) visits. The TL shortening were estimated by TL decline and TL ratio. We found that the urinary level of 1-hydroxypyrene (1-OHP) had significant dose-response relationships with increased TL decline [β(95%CI) = 0.078(0.023, 0.133), P = 0.005] and TL ratio [β(95%CI) = 0.096(0.037, 0.155), P = 0.002]. Besides, urinary 1-hydroxynaphthalene (1-OHNa) was marginally dose-related with elevated TL decline [β(95%CI) = 0.053(-0.001, 0.107), P = 0.055] and TL ratio [β(95%CI) = 0.057(-0.002, 0.116), P = 0.058]. Analyses of TERT-CLPTM1L variants showed that the rs401681 and rs465498 could modify the effect of 1-OHP on increasing TL decline (Pinteraction = 0.012 and 0.035, respectively) and TL ratio (Pinteraction = 0.014 and 0.067, respectively), which were pronounced among rs401681TT and rs465498CC carriers, but not seen among rs401681TC + CC and rs465498CT + TT carriers. In conclusion, elevated exposure to PAHs can accelerate the TL shortening and this effect can be modified by TERT-CLPTM1L variants. These results may add potential evidence for gene-environment interactions on dynamic changes of telomere length. Further studies are warranted to validate these findings and uncover the underlying mechanisms.

Heavy Exposure of Waste Collectors to Polycyclic Aromatic Hydrocarbons in a Poor Rural Area of Middle China.

Manual collection and open-air incineration of waste materials is a common practice in rural regions of China and beyond. Low-temperature combustion of rubber and plastic waste generates high levels of airborne polycyclic aromatic hydrocarbons (PAHs). We investigated ten urinary hydroxylated PAH metabolites (OH-PAHs), the oxidative damage biomarker (8-hydroxy-deoxyguanosine, 8-OHdG), and four serum biomarkers including gamma-glutamyl transferase (GGT) and alanine aminotransferase (ALT) in 41 waste collectors and 122 control subjects residing in the same or a distant rural village in Henan Province. The level of PAH metabolites in urine (median: 17.24 μg/g Cre) was twice that of controls living in the same area without an occupational history involving waste collection (median: 8.16 μg/g Cre) and thrice that of controls living 30 km away (median: 6.07 μg/g Cre). The concentrations of OH-PAHs were positively associated with urinary 8-OHdG levels (β = 0.283, p < 0.05). Serum GGT and ALT were slightly increased in waste collectors. Urinary 8-OHdG levels were similar in one-year and longer-term workers, suggesting that rubber and plastic waste collection/incineration carries a high PAH exposure risk. These data provide solid baseline information, emphasizing the importance of monitoring the long-term health outcomes of waste collectors and changes in exposure patterns associated with rural development and regulation of waste disposal.

Exposure to polycyclic aromatic hydrocarbons, vitamin D, and lung function in children with asthma.

It is unclear whether exposure to polycyclic aromatic hydrocarbons (PAH) affects lung function in children with asthma. Whether vitamin D insufficiency enhances any detrimental effects of PAH on lung function in asthmatic children is also unknown. Cross-sectional study of 1,821 children (6-17 years) who participated in the 2007-2012 National Health and Nutrition Examination Survey. Multivariable linear regression was used to analyze the relation between molar mass of urinary PAH metabolites (sum of all PAH (ΣmolPAH), sum of PAH with 2 benzene rings (Σmol2-PAH), or sum of PAH with 3 or 4 benzene rings (Σmol3,4-PAH)) and lung function or exhaled fraction of nitric oxide (FeNO) in children with and without asthma. In this multivariable analysis, we tested whether vitamin D insufficiency (a serum 25(OH)D level <30 ng/mL) interacts with PAH exposure on lung function in children with asthma. Children in the highest quartiles of urinary Σmol3,4-PAH had 2.3 times increased odds of asthma than those in the lowest quartile of Σmol3,4-PAH. Urinary PAH were not associated with lung function in children with or without asthma. Given a significant interaction between vitamin D insufficiency and PAH metabolites on lung function in asthmatic children, we stratified the analysis by vitamin D status. In this analysis, urinary PAH metabolites were significantly associated with 2.7-3.9% reduced %predicted FEV1 and %predicted FEV1/FVC in children with asthma and vitamin D insufficiency, but not in those with asthma and vitamin D sufficiency. Vitamin D insufficiency and PAH exposure may have synergistic detrimental effects on lung function in asthmatic children.

Characteristics and potential health risk of rural Tibetans' exposure to polycyclic aromatic hydrocarbons during summer period

Biomass fuels remain main energy sources in many remote rural regions, but potential health hazards from exposure to biomass combustion fumes have not been adequately assessed. Combustion of biomass fuels generates abundant polycyclic aromatic hydrocarbons (PAHs); hence residential exposure to PAHs can be used to evaluate the potential health risk to remote rural populations. The present study selected rural Tibetans to address the above-mentioned issue. Samples of indoor air and dust, human urine and local foods (Tsampa flour and buttered tea) were collected from five rural households in Langkazi County, an agricultural and pasturing region in Tibet of China in the summer season, which represented the best-case scenario as no heating was required. Residential exposure to PAHs by adults amounted to benzo[a]pyrene equivalent (BaPeq) dosages of 110–760, 1.2–50 and 0.5–23 ng d−1 for ingestion, inhalation and dermal contact, respectively. Daily intakes of naphthalene, fluorene, phenanthrene and pyrene estimated from urinary monohydroxy PAH metabolites and from diet and inhalation exposure to PAHs were comparable (3.9, 1.9, 12 and 3.3 μg d−1 versus 9.5, 2.5, 5.1 and 1.1 μg d−1), indicating the utility of external exposure in assessing daily intake of PAHs. The median incremental lifetime cancer risk was 32 × 10−6 (95% confidence interval: 0.7–73 × 10−6) for ingestion and 2.4 × 10−6 (95% confidence interval: 0.02–12 × 10−6) for inhalation and dermal contact combined, indicating moderate to slight potential cancer risk. Diet is the dominant source of health hazards for rural Tibetans, but cooking fumes also present a meaningful concern. The present study demonstrates that the pristine lifestyles of remote rural residents may be of global health concern, and merit further investigations.

Urinary polycyclic aromatic hydrocarbon metabolites and adult asthma: a case-control study

Polycyclic aromatic hydrocarbons (PAHs) exposure was reported to be associated with childhood asthma. However, the quantitative relationship between PAHs exposure and adult asthma and possible inflammatory pathways are less clear. We aimed to investigate potential associations between urinary PAHs metabolites and adult asthma. We enrolled 507 adult asthma cases and 536 matched controls. The concentrations of 12 urinary PAHs metabolites and plasma cytokines of interleukin (IL)-9 and eotaxin were measured. Potential associations between urinary PAHs metabolites and adult asthma were analyzed by logistic regression. The relationships between urinary PAHs metabolites and plasma cytokines were determined by generalized linear regression. After adjusted for covariates, each 1-unit-increase in natural log-transformed concentrations of 2-hydroxyfluorene (2-OHFLU), 4- hydroxyphenanthrene (4-OHPHE), 1-OHPHE, 2-OHPHE, 1-Hydroxypyrene (1-OHPYR) and ∑OH-PAHs were significantly associated with elevated risk of adult asthma with odds ratios of 2.04, 2.38, 2.04, 1.26, 2.35 and 1.34, respectively. And the associations were more pronounced in the subjects who were female, younger than 45 years, smoker and had history of occupational dust exposure. No associations were observed between urinary PAHs metabolites levels and expressions of IL-9 and eotaxin. Our results demonstrated that elevated urinary PAHs metabolites levels were associated with increased risk of asthma in adults.