Dose-response relationship between polycyclic aromatic hydrocarbon metabolites and risk of diabetes in the general Chinese population

Environment-wide association study of cardiovascular and all-cause mortality: Analysis of the National Health and Nutrition Examination Survey, 1999-2018

Environmental toxicants are increasingly suspected to influence cardiovascular (CV) and all-cause mortality, but previous studies mostly focused on one or a few chemicals. We examined the associations of a wide array of environmental chemicals with CV and all-cause mortality using an exposome-wide approach and the potential mediating role of inflammation in these associations. Data from the National Health and Nutrition Examination Survey (1999-2018) were randomly 60:40 split into a training set and a test set. The mortality rates were determined by the National Center for Health Statistics through a process of correlation with the National Death Index records. Based on the 10th revision of (ICD-10) codes, deaths due to heart disease (ICD 100-I09, I11, I13, and I20-I51) or cerebrovascular disease (I60-I69) were defined as CV mortality. Using the NHANES data, with a median 9.42-year follow-up period, we found that higher concentrations of 2-hydroxynaphthalene (2-NAP) and 2-hydroxyfluorene (2-FLU) in the urine, heavy metal cadmium (Cd), and cotinine in the blood were associated with increased risks of both CV and all-cause mortality. We further found 11 chemicals, including polycyclic aromatic hydrocarbons (1-hydroxynaphthalene, 3-hydroxyfluorene, and 9-hydroxyfluorene), 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanol (NNAL) in the urine; hydroxycotinine, heavy metals lead, volatile organic compounds (benzene, ethylbenzene, styrene, toluene and 2,5-Dimethylfuran) in the blood were positively associated with all-cause mortality. Furthermore, we found that C-reactive protein levels partially mediate those associations. In summary, exposure to certain environmental chemicals was associated with CV and all-cause mortality, and C-reactive protein plays a mediation role in those associations. Our findings provided more evidence for preventing and controlling important environmental chemicals to improve people's health.

Cardiovascular risk factors in relation to hair polycyclic aromatic hydrocarbons in the NESCAV study

Previous studies have found associations between exposure to polycyclic aromatic hydrocarbons (PAHs) and cardiovascular risk factors. However, the internal dose of PAH exposure was often examined by quantifying monohydroxylated metabolites of PAHs (OH-PAHs) in urine, which can only reflect recent exposure. On the other hand, hair covers wider temporal windows than urine and has been demonstrated to be a suitable matrix for PAH exposure assessment. Using hair analysis, here we investigated the associations between PAH exposure and obesity, diabetes, hypertension, dyslipidemia, and metabolic syndrome (MetS) and its components in a cross-sectional study of adults aged 18-69 years and enrolled in the Nutrition, Environment and Cardiovascular Health (NESCAV) survey conducted in 2007-2009 in Luxembourg. In addition, we also examined hair cotinine and nicotine because they are well-established biomarkers of tobacco smoke exposure. Associations were explored separately for men (n = 265) and women (n = 347) by logistic regression with adjustment for potential confounders. We found positive associations of OH-PAHs with diabetes in both men and women, positive and inverse associations with obesity and positive associations with hypertension/elevated blood pressure and dyslipidemia/elevated triglycerides (TG) in men, and inverse associations with hypertension but positive associations with MetS, elevated waist circumference and reduced high-density lipoprotein cholesterol (HDL-C) in women. These results may suggest that men and women differ in cardiometabolic responses to environmental PAH exposure. As regards hair cotinine and nicotine, they were associated with diabetes/elevated fasting plasma glucose, elevated blood pressure, and dyslipidemia/elevated TG/reduced HDL-C in men and women. Our results suggest that exposure to PAHs and tobacco smoke may be associated with cardiometabolic health risk. Future prospective studies are warranted to corroborate these findings.

Induction of insulin resistance in female mice due to prolonged phenanthrene exposure: Unveiling the low-dose effect and potential mechanisms

Phenanthrene (Phe) is a commonly occurring polycyclic aromatic hydrocarbon (PAH) found in various food sources and drinking water. Previous studies have shown that long-term exposure to Phe in male mice leads to insulin resistance in a dose-dependent manner. However, the effect of Phe on glucose homeostasis in female mice remains unknown. To address this knowledge gap, female Kunming mice were exposed to Phe through their drinking water at concentrations of 0.05, 0.5, and 5 ng/mL. After 270 d of exposure, we surprisingly discovered a low-dose effect of Phe on insulin resistance in female mice, which differed from the effect observed in male mice and showed sexual dimorphism. Specifically, insulin resistance was only observed in the 0.05 ng/mL treatment, and this low-dose effect was also reflected in the concentration of Phe in white adipose tissue (WAT). Differences in metabolic enzyme activities in the liver may potentially explain this effect. The observed sexual dimorphism in Phe exposure could be attributed to variations in estrogen (E2) level and estrogen receptor beta (ERβ) expression in WAT. These findings highlight the association between environmental factors and the development of insulin resistance, emphasizing the pathogenic effect of even low doses of Phe. Moreover, sex dependent-effect should be given more attention when studying the toxic effects of environmental pollutants.

Smoked and Fermented Bushmeat (Mpunam) Products: Risk Assessment of Polycyclic Aromatic Hydrocarbons (PAHs) Resulting From Processing

The polycyclic aromatic hydrocarbons (PAHs) congener concentrations and risk upon human exposure to smoked bushmeat products were analyzed. GC/MS MRM and QuEChERS methods were used for the analysis. This work has become necessary due to the need for more information concerning the quantitative determination of these compounds and their health risk assessment. The 16 PAH congeners identified were acenaphthylene (ACA), naphthalene (NAP), acenaphthene (ACE), fluorene (FLU), anthracene (ANT), phenanthrene (PHE), fluoranthene (FLT), pyrene (PYR), benzo[b]fluoranthene (BBF), benzo[k]fluoranthene (BKF), benzo[a]anthracene (BAA), chrysene (CHR), indeno(1,2,3-cd)pyrene (IND), dibenzo(a,h)anthracene (DAA), benzo(g,h,i)pyrene (BGP), and benzo[a]pyrene (BAP). At the 5% and 95% daily intake levels, BAP was at 3.34 and 17.39 μg/kg(bw)/day, ΣPAH4 was at 25.11 and 109.15 μg/kg(bw)/day, and ΣPAH8 was at 55.76 and 236.68 μg/kg(bw)/day, respectively. BAP, ΣPAH4, and ΣPAH8 concentration exceeded the European Union limits, as BAP concentration was as low as 6.09 μg/kg and as high as 34.19. The exposure values were significantly high. Specifically, the margin of exposure for BAP was as low as 2.09 × 10-2; for ΣPAH4, it was 1.36 × 10--2; and for ΣPAH8, it was 1.95 × 10-2 all at the 95% level. These figures are substantially lower than the benchmark of 10,000, indicating a higher ILTCR. Furthermore, the ILTCR ranged from a minimum of 47.77 to a maximum of 248.53 at the 5% and 95% levels, respectively. This study makes smoked bushmeat a public health concern because the higher figures obtained indicate higher carcinogenicity upon consumption.

The key metabolic signatures and biomarkers of polycyclic aromatic hydrocarbon-induced blood glucose elevation in chinese individuals exposed to diesel engine exhaust

Due to the complexity of environmental exposure factors and the low levels of exposure in the general population, identifying the key environmental factors associated with diabetes and understanding their potential mechanisms present significant challenges. This study aimed to identify key polycyclic aromatic hydrocarbons (PAHs) contributing to increased fasting blood glucose (FBG) concentrations and to explore their potential metabolic mechanisms. We recruited a highly PAH-exposed diesel engine exhaust testing population and healthy controls. Our findings found a positive association between FBG concentrations and PAH metabolites, identifying 1-OHNa, 2-OHPh, and 9-OHPh as major contributors to the rise in FBG concentrations induced by PAH mixtures. Specifically, each 10 % increase in 1-OHNa, 2-OHPh, and 9-OHPh concentrations led to increases in FBG concentrations of 0.201 %, 0.261 %, and 0.268 %, respectively. Targeted metabolomics analysis revealed significant alterations in metabolic pathways among those exposed to high levels of PAHs, including sirtuin signaling, asparagine metabolism, and proline metabolism pathway. Toxic function analysis highlighted differential metabolites involved in various dysglycemia-related conditions, such as cardiac arrhythmia and renal damage. Mediation analysis revealed that 2-aminooctanoic acid mediated the FBG elevation induced by 2-OHPh, while 2-hydroxyphenylacetic acid and hypoxanthine acted as partial suppressors. Notably, 2-aminooctanoic acid was identified as a crucial intermediary metabolic biomarker, mediating significant portions of the associations between the multiple different structures of OH-PAHs and elevated FBG concentrations, accounting for 16.73 %, 10.84 %, 10.00 %, and 11.90 % of these effects for 1-OHPyr, 2-OHFlu, the sum concentrations of 2- and 9-OHPh, and the sum concentrations of total OH-PAHs, respectively. Overall, our study explored the potential metabolic mechanisms underlying the elevated FBG induced by PAHs and identified 2-aminooctanoic acid as a pivotal metabolic biomarker, presenting a potential target for intervention.

Lifestyle factors modified the mediation role of liver fibrosis in the association between occupational physical activity and blood pressure

Objectives

The study aimed to estimate the role of liver fibrosis in the association between occupational physical activity (OPA) and blood pressure (BP), which is modified by lifestyle factors.

Methods

The questionnaire survey and physical examination were completed among 992 construction workers in Wuhan, China. Associations between OPA or lifestyle factors and liver fibrosis indices and blood pressure were assessed using generalized additive models. The mediation analysis was used to evaluate the role of liver fibrosis in the association between OPA and lifestyle factors and BP.

Results

Moderate/high OPA group workers had an increased risk of liver fibrosis [odds ratio (OR) = 1.69, 95% confidence intervals (CI): 1.16-2.47, P < 0.05] compared with low OPA group workers. Smoking or drinking alcohol was related to liver fibrosis (aspartate aminotransferase to platelet ratio index: OR = 2.22, 95% CI: 1.07-4.62 or OR = 2.04, 95% CI: 1.00-4.15; P < 0.05). Compared with non-drinkers, drinkers were related to a 2.35-mmHg increase in systolic blood pressure (95% CI: 0.09-4.61), and a 1.60-mmHg increase in diastolic blood pressure (95% CI: 0.08-3.13; P < 0.05). We found a significant pathway, "OPA → liver fibrosis → blood pressure elevation," and lifestyle factors played a regulatory role in the pathway.

Conclusion

OPA or lifestyle factors were associated with liver fibrosis indices or BP in construction workers. Furthermore, the association between OPA and BP may be partially mediated by liver fibrosis; lifestyle factors strengthen the relationship between OPA and BP and the mediation role of liver fibrosis in the relationship.

Healthy lifestyle and essential metals attenuated association of polycyclic aromatic hydrocarbons with heart rate variability in coke oven workers

Whether adopting healthy lifestyles and maintaining moderate levels of essential metals could attenuate the reduction of heart rate variability (HRV) related to polycyclic aromatic hydrocarbons (PAHs) exposure are largely unknown. In this study, we measured urinary metals and PAHs as well as HRV, and constructed a healthy lifestyle score in 1267 coke oven workers. Linear regression models were used to explore the association of healthy lifestyle score and essential metals with HRV, and interaction analysis was performed to investigate the potential interaction between healthy lifestyle score, essential metals, and PAHs on HRV. Mean age of the participants was 41.9 years (84.5% male). Per one point higher healthy lifestyle score was associated with a 2.5% (95% CI, 1.0%-3.9%) higher standard deviation of all normal to normal intervals (SDNN), 2.1% (95% CI, 0.5%-3.6%) higher root mean square of successive differences in adjacent NN intervals (r-MSSD), 4.3% (95% CI, 0.4%-8.2%) higher low frequency, 4.4% (95% CI, 0.2%-8.5%) higher high frequency, and 4.4% (95% CI, 1.2%-7.6%) higher total power, respectively. Urinary level of chromium was positively associated with HRV indices, with the corresponding β (95% CI) (%) was 5.17 (2.84, 7.50) for SDNN, 4.29 (1.74, 6.84) for r-MSSD, 12.26 (6.08, 18.45) for low frequency, 12.61 (5.87, 19.36) for high frequency, and 11.31 (6.19, 16.43) for total power. Additionally, a significant interaction was found between healthy lifestyle score and urinary total hydroxynaphthalene on SDNN (Pinteraction = 0.04), and higher level of urinary chromium could attenuate the adverse effect of total hydroxynaphthalene level on HRV (all Pinteraction <0.05). Findings of our study suggest adopting healthy lifestyle and maintaining a relatively high level of chromium might attenuate the reduction of HRV related to total hydroxynaphthalene exposure.

Parent and halogenated polycyclic aromatic hydrocarbons exposure in aluminum smelter workers: Serum levels, accumulation trends, and association with health indicators

Polycyclic aromatic hydrocarbons (PAHs) and their halogenated derivatives (HPAHs) can be unintentionally formed and released during industrial thermal processes. However, information on internal exposure and health risks of PAHs and HPAHs for thermal industry workers is very limited. In this study, serum samples from 220 aluminum smelter workers in East China were analyzed, and the relationship between the levels of these pollutants and various health indicators was also assessed. The workers had markedly higher serum concentrations of PAHs and HPAHs than the controls. The serum concentrations of ∑13PAHs and ∑9HPAHs increased with increasing age and occupational exposure duration in male workers. A positive correlation was observed between the ∑13PAH and ∑9HPAH serum concentrations, and the concentration of ∑13PAHs was approximately 50 times higher than that of ∑9HPAHs. For benzo[a]pyrene equivalent (BaPeq)-based risk assessment, the contribution of PAHs and HPAHs to the risk was 80 % and 20 % in the workers. PAHs and HPAHs showed a positive association with pulmonary hypofunction, hypertension and abnormal electrocardiogram. This study indicates occupational exposure to these toxic pollutants remains a significant issue and provides evidence that elevated serum levels of ∑13PAHs and ∑9HPAHs may be associated with an increased risk of lung and cardiovascular diseases.

Association of urinary polycyclic aromatic hydrocarbon metabolites with gestational diabetes mellitus and gestational hypertension among pregnant women in Southwest China: A cross-sectional study

The association of polycyclic aromatic hydrocarbons (PAHs) with gestational diabetes mellitus (GDM) and gestational hypertension during pregnancy has not yet been established. To investigate the association between PAH exposure and GDM and gestational hypertension, we conducted a cross-sectional study of 4206 pregnant women from the Zunyi birth cohort in southwestern China. Gas chromatography/mass spectrometry was used to detect the urinary levels of 10 monohydroxylated PAHs (OH-PAHs). GDM and gestational hypertension were diagnosed and the relevant information was documented by specialist obstetricians and gynecologists. Logistic regression and restricted cubic spline regression were employed to investigate their single and nonlinear associations. Stratified analyses of pregnancy and body mass index data were conducted to determine their moderating effects on the abovementioned associations. Compared with the first quartile of urinary ∑OH-PAHs, the third or fourth quartile in all study participants was associated with an increased risk of GDM (quartile 3: odds ratio [OR] = 1.35, 95% confidence interval [CI]: 1.03-1.77) and gestational hypertension (quartile 3: OR = 1.88, 95% CI: 1.26-2.81; quartile 4: OR = 1.58, 95% CI: 1.04-2.39), respectively. Nonlinear associations of 1-OH-PYR with GDM (cutoff level: 0.02 μg/g creatinine [Cr]) and 1-OH-PHE with gestational hypertension (cutoff level: 0.06 μg/g Cr) were also observed. In pregnant women with overweight or obesity, 1-OH-PHE and 3-OH-PHE were more strongly associated with gestational hypertension. Our results indicate that exposure to PAH during pregnancy may significantly increase the maternal risks of GDM and gestational hypertension; however, this finding still needs to be confirmed through larger-scale prospective studies and biological evidence.

Diabetes: a potential mediator of associations between polycyclic aromatic hydrocarbon exposure and stroke

Epidemiological evidence suggests associations between exposure to polycyclic aromatic hydrocarbons (PAHs) and cardiovascular diseases (CVD), while diabetes is a common risk factor for CVD. The present study aims to clarify the effect of high PAH exposure on diabetes and stroke in general population. A total of 7849 individuals aged 20 years or older from the National Health and Nutrition Examination Survey 2007-2016 were included in the study. The logistic regression analysis modeled the association between PAH exposure and diabetes as well as stroke. The analysis yielded odds ratios (ORs) and 95% confidence intervals (CIs). The study also evaluated the potential mediating role of diabetes in the relation between PAH exposure and stroke via mediating effect analyses. Of the 7849 eligible participants, 1424 cases of diabetes and 243 cases of stroke were recorded. After adjusting for covariates including age, gender, smoking status, drinking status, education level, marital status, physical activity, hypertension, low-density lipoprotein cholesterol, and BMI, the ORs for stroke in the highest quartile (Q4) of total urinary PAHs were 1.97 (95% CI 1.11-3.52, P = 0.022) as compared to the lowest quartile (Q1) of total urinary PAHs. The ORs for diabetes in the Q4 of total urinary PAHs were 1.56 (95% CI 1.15-2.12, P = 0.005), while the ORs between Q4 and Q1 for stroke and diabetes concerning exposure to 2-hydroxynaphthalene were 2.23 (95% CI 1.17-4.25, P = 0.016) and 1.40 (95% CI 1.07-1.82, P = 0.015), respectively. The mediation analysis found that diabetes accounted for 5.00% of the associations between urinary PAHs and the prevalence of stroke. Urinary metabolites of PAH have been linked to stroke and diabetes. Increasing the risk of diabetes may play a significant role in mediating the association between exposure to PAHs and increased risk of stroke. Monitoring and improving glucose metabolism in individuals with high exposure to PAHs may aid in reducing the prevalence of stroke.

Biomarkers for polycyclic aromatic hydrocarbons in human excreta: recent advances in analytical techniques-a review

Polycyclic aromatic hydrocarbons (PAHs) are widespread environmental pollutants that are generated by the incomplete combustion of organic materials. The main anthropogenic sources of PAHs are the combustion of solid fuels for heating purposes, illegal waste incineration, road transport and industries based on fossil fuels. PAHs can easily enter the body because they are present in all elements of the environment, including water, soil, air, and food. Due to their ubiquitous presence, PAHs, may exert a harmful effect on human health. Assessing PAH exposure through biomonitoring mostly involve techniques to measure the concentration of 1-hydroxypyrene in human urine. Nevertheless, through recent progress in analytical techniques, other common metabolites of PAHs in human biospecimens can be detected. A scientific literature search was conducted to determine which hydroxy derivatives of PAHs are markers of PAHs exposure and to reveal the leading sources of these compounds. Techniques for analyzing biological samples to identify OH-PAHs are also discussed. The most frequently determined OH-PAH in human urine is 1-hydroxypyrene, the concentration of which reaches up to a dozen ng/L in urine. Apart from this compound, the most frequently determined biomarkers were naphthalene and fluorene metabolites. The highest concentrations of 1- and 2-hydroxynaphthalene, as well as 2-hydroxyfluorene, are associated with occupational exposure and reach approximately 30 ng/L in urine. High molecular weight PAH metabolites have been identified in only a few studies. To date, PAH metabolites in feces have been analyzed only in animal models for PAH exposure. The most frequently used analytical method is HPLC-FLD. However, compared to liquid chromatography, the LOD for gas chromatography methods is at least one order of magnitude lower. The hydroxy derivatives naphthalene and fluorene may also serve as indicators of PAH exposure.

Association of Polycyclic Aromatic Hydrocarbons Urine Metabolites with Type 1 Diabetes

Purpose

Polycyclic aromatic hydrocarbons (PAHs) are believed to be a possible factor in the development of cancer, ischemic heart disease, obesity, and cardiovascular disease. The objective of this study was to explore the association between certain metabolites of urinary PAH and type 1 diabetes (T1D).

Methods

In Isfahan City, a case-control study was carried out involving 147 T1D patients and an equal number of healthy individuals. The study measured the levels of urinary metabolites of PAHs, specifically 1-hydroxynaphthalene, 2-hydroxynaphthalene, and 9-hydroxyphenanthrene, in both the case and control groups. The levels of these metabolites were then compared between the two groups to assess any potential association between the biomarkers and T1D.

Results

The mean (SD) age of participants in the case and control groups was 8.4 (3.7) and 8.6 (3.7) years old, respectively, (P > 0.05). In terms of gender distribution, 49.7% and 46% of participants in the case and control groups were girls, respectively (P > 0.05). Geometric mean (95% CI) concentrations were: 36.3 (31.4-42) μg/g creatinine for 1-hydroxynaphthalene, 29.4 (25.6-33.8) μg/g creatinine for 2-hydroxynaphthalene, and 72.26 (63.3-82.5) μg/g creatinine for NAP metabolites. After controlling for variables such as the child's age, gender, maternal and paternal education, duration of breastfeeding, exposure to household passive smoking, formula feeding, cow's milk consumption, body mass index (BMI), and five dietary patterns, it was observed that individuals in the highest quartile of 2-hydroxynaphthalene and NAP metabolites had a significantly greater odd ratio for diabetes compared to those in the lowest quartile (P < 0.05).

Conclusion

Based on the findings of this study, it is suggested that exposure to PAH might be linked to an increased risk of T1D in children and adolescents. To clarify a potential causal relationship related to these findings, further prospective studies are needed.

Research progress in human biological monitoring of aromatic hydrocarbon with emphasis on the analytical technology of biomarkers

Aromatic hydrocarbons are unsaturated compounds containing carbon and hydrogen that form single aromatic ring, or double, triple, or multiple fused rings. This review focuses on the research progress of aromatic hydrocarbons represented by polycyclic aromatic hydrocarbons (including halogenated polycyclic aromatic hydrocarbons), benzene and its derivatives including toluene, ethylbenzene, xylenes (o-, m- and p-), styrene, nitrobenzene, and aniline. Due to the toxicity, widespread coexistence, and persistence of aromatic hydrocarbons in the environment, accurate assessment of exposure to aromatic hydrocarbons is essential to protect human health. The effects of aromatic hydrocarbons on human health are mainly derived from three aspects: different routes of exposure, the duration and relative toxicity of aromatic hydrocarbons, and the concentration of aromatic hydrocarbons which should be below the biological exposure limit. Therefore, this review discusses the primary exposure routes, toxic effects on humans, and key populations, in particular. This review briefly summarizes the different biomarker indicators of main aromatic hydrocarbons in urine, since most aromatic hydrocarbon metabolites are excreted via urine, which is more feasible, convenient, and non-invasive. In this review, the pretreatment and analytical techniques are compiled systematically for the qualitative and quantitative assessments of aromatic hydrocarbons metabolites such as gas chromatography and high-performance liquid chromatography with multiple detectors. This review aims to identify and monitor the co-exposure of aromatic hydrocarbons that provides a basis for the formulation of corresponding health risk control measures and guide the adjustment of the exposure dose of pollutants to the population.

Association of occupational exposure to polycyclic aromatic hydrocarbons in workers with hypertension from a northeastern Chinese petrochemical industrial area

Elevated urinary polycyclic aromatic hydrocarbon metabolites have been linked to an increased risk of cardiovascular diseases (CVDs). However, for petrochemical workers with potentially high PAH exposure, it remains largely unknown whether the link will be amplified. Thus, this work aimed to investigate 14 urinary mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) in 746 petrochemical workers working in a Chinese petrochemical industrial area and their association with the risk of hypertension using the binary logistic regression. Metabolites of naphthalene, fluorene, phenanthrene, and pyrene were frequently detected in the 746 urine samples analyzed (>98%), with Σ₁₀OH-PAH concentration in the range of 0.906-358 ng/mL. 2-hydroxynaphthalene accounted for the largest proportion of ten detected OH-PAHs (60.8% of Σ₁₀OH-PAHs). There were significant correlations between these metabolites and other factors, including gender, age, and body mass index. Diastolic blood pressure, not systolic blood pressure, was significant positively associated with the urinary Σ₁₀OH-PAH concentrations of the petrochemical workers. Elevated urinary 2/3-OH-Flu was significantly associated with an increased risk of hypertension (adjusted odds ratio: 1.96, 95% confidence interval: 1.20-3.18, p = 0.007), suggesting that PAH exposure in petrochemical workers was a driving factor of hypertension. In the stratified analysis, the association was more pronounced in those who were overweight with older age. Although the PAH exposure risk in petrochemical workers based on the estimated daily intakes was relatively low. Given the long-term impact, we call attention to CVDs of petrochemical workers.

Lung versus gut exposure to air pollution particles differentially affect metabolic health in mice

BACKGROUND

Air pollution has emerged as an unexpected risk factor for diabetes. However, the mechanism behind remains ill-defined. So far, the lung has been considered as the main target organ of air pollution. In contrast, the gut has received little scientific attention. Since air pollution particles can reach the gut after mucociliary clearance from the lungs and through contaminated food, our aim was to assess whether exposure deposition of air pollution particles in the lung or the gut drive metabolic dysfunction in mice.

METHODS

To study the effects of gut versus lung exposure, we exposed mice on standard diet to diesel exhaust particles (DEP; NIST 1650b), particulate matter (PM; NIST 1649b) or phosphate-buffered saline by either intratracheal instillation (30 µg 2 days/week) or gavage (12 µg 5 days/week) over at least 3 months (total dose of 60 µg/week for both administration routes, equivalent to a daily inhalation exposure in humans of 160 µg/m³ PM_2.5) and monitored metabolic parameters and tissue changes. Additionally, we tested the impact of the exposure route in a "prestressed" condition (high-fat diet (HFD) and streptozotocin (STZ)).

RESULTS

Mice on standard diet exposed to particulate air pollutants by intratracheal instillation developed lung inflammation. While both lung and gut exposure resulted in increased liver lipids, glucose intolerance and impaired insulin secretion was only observed in mice exposed to particles by gavage. Gavage with DEP created an inflammatory milieu in the gut as shown by up-regulated gene expression of pro-inflammatory cytokines and monocyte/macrophage markers. In contrast, liver and adipose inflammation markers were not increased. Beta-cell secretory capacity was impaired on a functional level, most likely induced by the inflammatory milieu in the gut, and not due to beta-cell loss. The differential metabolic effects of lung and gut exposures were confirmed in a "prestressed" HFD/STZ model.

CONCLUSIONS

We conclude that separate lung and gut exposures to air pollution particles lead to distinct metabolic outcomes in mice. Both exposure routes elevate liver lipids, while gut exposure to particulate air pollutants specifically impairs beta-cell secretory capacity, potentially instigated by an inflammatory milieu in the gut.

Supported liquid extraction and ultra-high performance liquid chromatography-tandem mass spectrometry for the determination of urinary polycyclic aromatic hydrocarbon metabolites and their application for human biomonitoring

Polycyclic aromatic hydrocarbons (PAHs) are a class of highly lipophilic and ubiquitous, persistent organic pollutants with carcinogenic and mutagenic toxicities. They are a great public health concern, and avoiding exposure to them is a high priority. Human biomonitoring is critical for the evaluation of exposure levels to PAHs by the general population. In this work, we demonstrated the biomonitoring of eleven hydroxylated PAHs (OHPAHs) in urine samples from 226 volunteers from Guangzhou, and evaluated the health risks. The urinary PAH metabolites were released by enzymatic deconjugation, separated, and enriched by supported liquid extraction, and then quantified by ultra-high performance liquid chromatography-tandem mass spectrometry. The limit of quantification of the individual OHPAHs ranged from 10 ng/L to 40 ng/L, and satisfactory recoveries were obtained, ranging from 92.6% to 97.6%. The detection frequencies of the OHPAHs were 100%, and naphthalene metabolites were found at the highest concentrations with a geometric mean of 8.61 μg/L. The mean total OHPAH level in the urine samples of males (13.2 μg/L) was significantly higher than that of females (5.84 μg/L). Pearson correlation analyses indicated significant and positive correlations among urinary OHPAHs. The total estimated daily intake of PAHs was calculated, and a low health risk was obtained by evaluating their hazard quotients and hazard indexes.

Developing a profile of urinary PAH metabolites among Chinese populations in the 2010s

Polycyclic aromatic hydrocarbons (PAHs) pose significant health risks. However, no nationwide cohort has been established to consistently record biomonitoring data on PAH exposure in the Chinese population. Biomonitoring data from 56 published studies were combined in this study to develop a profile of urinary PAH metabolites among Chinese population in the 2010s. The stacked column charts described the composition profiles of hydroxylated PAHs (OH-PAHs) in general, special, and occupational populations. Hydroxynaphthalene (OH-Nap) and hydroxyfluorene (OH-Flu) accounted for more than half of the urinary OH-PAH in general and special populations. The urine of the occupational populations contained a significant amount of hydroxyphenanthrene (OH-Phe) and 1-hydroxypyrene (1-OHPyr). Furthermore, this study analyzed the distribution profiles of non-occupationally exposed populations, such as spatial distribution, age distribution, and trends over time. The population of the Southern region had higher urinary OH-PAH concentrations than the population of the Northern region. Adults (45-55 years old) had the highest level of internal PAH exposure. Between 2010 and 2018, the overall trend of urinary OH-PAHs in Chinese general populations decreased. The cumulative distribution function (CDF) revealed that 1-OHNap and 1-OHPyr were better at distinguishing internal PAH exposure among different populations. The sum of OH-Flu and OH-Phe in urine can be used to assess the impact of indoor and outdoor environments on human exposure to PAHs. Our findings suggest that more emphasis should be placed on collecting biomonitoring data for adults of all ages (particularly in the Northern region) and vulnerable populations. In conclusion, this study advocates for the establishment of a nationwide cohort study of Chinese populations as soon as possible in the future to evaluate the Chinese population's exposure to environmental contaminants.

Thermodynamics of benzoquinone-induced conformational changes in nucleic acids and human serum albumin

Biological macromolecules such as proteins, nucleic acids, carbohydrates and lipids, play a crucial role in biochemical and molecular processes. Thus, the study of the structure-function relationship of biomolecules in presence of ligands is an important aspect of structural biology. The current communication describes the chemico-biological interaction between benzene metabolite para-benzoquinone (BQ) with B-form of nucleic acids (B-DNA) and human serum albumin (HSA). The binding ability of HSA towards bromocresol green (BCG) was significantly suppressed when exposed to increasing concentrations of BQ in the presence of various physiological buffers. Further, the native fluorescence of HSA was drastically reduced and the secondary structures of HSA were significantly compromised with increasing concentrations of BQ. In vitro and in silico studies also revealed that BQ binds to domains I and II of HSA and thus altering the conformation of HSA which may potentially affect plasma osmotic pressure, as well as the binding and transport of numerous endogenous and exogenous molecules. Similarly, BQ interacts directly to the GC region of B-DNA particularly in the minor groove which was also assessed by computational docking studies. Isothermal titration calorimetry data suggest higher binding affinity of BQ towards DNA than HSA. Various spectroscopic observations also suggest that BQ binds to DNA preferably in the minor grooves. Thus, the results revealed that BQ may play a key role in inducing mutagenicity, either by formation of adducts on GC regions or by accelerating oxidative damage to biomacromolecules through chemico-biological interactions.

Long-term exposure to low concentrations of polycyclic aromatic hydrocarbons and alterations in platelet indices: A longitudinal study in China

Long-term exposure to low polycyclic aromatic hydrocarbon (PAH) concentration may ave detrimental effects, including changing platelet indices. Effects of chronic exposure to low PAH concentrations have been evaluated in cross-sectional, but not in longitudinal studies, to date. We aimed to assess the effects of long-term exposure to the low-concentration PAHs on alterations in platelet indices in the Chinese population. During 2014–2017, we enrolled 222 participants who had lived in a village in northern China, 1–2 km downwind from a coal plant, for more than 25 years, but who were not employed by the plant or related businesses. During three follow-ups, annually in June, demographic information and urine and blood samples were collected. Eight PAHs were tested: namely 2-hydroxynaphthalene, 1-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene (9-OHFlu), 2-hydroxyphenanthrene (2-OHPh), 1-hydroxyphenanthrene (1-OHPh), 1-hydroxypyrene (1-OHP), and 3-hydroxybenzo [a] pyrene. Five platelet indices were measured: platelet count (PLT), platelet distribution width (PDW), mean platelet volume (MPV), platelet crit, and the platelet-large cell ratio. Generalized mixed and generalized linear mixed models were used to estimate correlations between eight urinary PAH metabolites and platelet indices. Model 1 assessed whether these correlations varied over time. Models 2 and 3 adjusted for additional personal information and personal habits. We found the following significant correlations: 2-OHPh (Model1 β₁ = 18.06, Model2 β₂ = 18.54, Model β₃ = 18.54), 1-OHPh (β₁ = 16.43, β₂ = 17.42, β₃ = 17.42), 1-OHP(β₁ = 13.93, β₂ = 14.03, β₃ = 14.03) with PLT, as well as 9-OHFlu with PDW and MPV (odds ratio or Model3 OR_PDW[95%CI] = 1.64[1.3–2.06], OR_MPV[95%CI] = 1.33[1.19–1.48]). Long-term exposure to low concentrations of PAHs, indicated by2-OHPh, 1-OHPh, 1-OHP, and 9-OHFlu, as urinary biomarkers, affects PLT, PDW, and MPV. 9-OHFlu increased both PDW and MPV after elimination of the effects of other PAH exposure modes.

AMER3 variants modify the U-shaped association of urinary total hydroxyphenanthrene with fasting plasma glucose: A newfound gene-environment interaction

As a polycyclic aromatic hydrocarbon, environmental exposure to phenanthrene is widespread worldwide. The potential effects and mechanism of phenanthrene exposure on fasting plasma glucose (FPG) have not been well determined. In this study, we aim to explore the effects of phenanthrene exposure and AMER3 variants on fasting plasma glucose (FPG) through a longitudinal epidemiological study. Repeated measurements of five urinary hydroxyphenanthrene (OHPh) for 5739 participants with 7083 observations from the Wuhan-Zhuhai cohort were performed to analyze the relationships between total OHPh (ΣOHPh) and FPG using linear mixed models and restricted cubic spline functions. Then, we genotyped 2777 participants (4104 observations) using the Infinium OmniZhongHua-8 BeadChip and included all 14 single nucleotide polymorphisms (SNPs) within the AMER3 gene to analyze the interaction of the AMER3 on the relationship between ΣOHPh and FPG. We observed a U-shaped relationship between ΣOHPh and FPG, and the turning point of ΣOHPh was 2.512 μg/mmol Cr. When lower than the turning point, ΣOHPh was negatively associated with FPG, while higher than the turning point, ΣOHPh was positively associated with FPG. Furthermore, we observed interactions (P_int <0.05) between two common variants (rs72854995 and rs72854999) of the AMER3 and ΣOHPh on FPG change: the U-shaped relationship was still observed in the GG genotype groups but not in the allele A carriers. Our results suggested that the AMER3 gene can modify the U-shaped relationship between phenanthrenes exposure and FPG, which showed a new gene-environment interaction and will provide a new perspective on the relationship between phenanthrene exposure and FPG.

Environmental polycyclic aromatic hydrocarbon exposure in relation to metabolic syndrome in US adults

The present study examined the associations of polycyclic aromatic hydrocarbon (PAH) exposure with metabolic syndrome (MetS) and its components. Data were from 5181 US adults recruited in the National Health and Nutrition Examine Survey 2001-2012. Environmental PAH exposure was estimated as concentrations of urinary PAH metabolites. Weighted quantile sum (WQS) regression and modified Poisson regression were separately conducted to estimate the associations of mixed and single PAH metabolites with MetS and its components. WQS regression analyses showed that participants with higher mixed PAH exposure had increased prevalence of MetS (prevalence ratio, 1.12; 95 % confidence interval, 1.06, 1.19), elevated waist circumference (1.07; 1.02, 1.12), elevated fasting blood glucose (1.07; 1.00, 1.14), elevated triglycerides (1.19; 1.09, 1.30), and reduced high-density lipoprotein cholesterol (1.11; 1.03, 1.20). In the models for single PAH metabolites, higher levels of 1-hydroxynaphthalene (1.15; 1.00, 1.32), 2-hydroxynaphthalene (1.20; 1.05, 1.38), 1-hydroxyphenanthrene (1.18; 1.04, 1.34), 2-hydroxyphenanthrene (1.38; 1.22, 1.57), and 1-pyrene (1.19; 1.05, 1.34) were respectively associated with increased prevalence of MetS (highest tertile vs lowest tertile). In addition, linear trends were noted for the associations of these PAH metabolites with MetS (all P for linear association ≤0.047). Smokers, drinkers, and participants with poor diet quality showed stronger associations between certain PAH metabolite with MetS. The findings suggest that the prevalence of MetS and its components increases when PAH exposure is at a high level, and that lifestyle factors, such as cigarette smoking, alcohol consumption, and diet quality, could modify the positive associations of certain PAH exposure with MetS.

Potential Toxicity Risk Assessment and Priority Control Strategy for PAHs Metabolism and Transformation Behaviors in the Environment

In this study, 16 PAHs were selected as the priority control pollutants to summarize their environmental metabolism and transformation processes, including photolysis, plant degradation, bacterial degradation, fungal degradation, microalgae degradation, and human metabolic transformation. Meanwhile, a total of 473 PAHs by-products generated during their transformation and degradation in different environmental media were considered. Then, a comprehensive system was established for evaluating the PAHs by-products' neurotoxicity, immunotoxicity, phytotoxicity, developmental toxicity, genotoxicity, carcinogenicity, and endocrine-disrupting effect through molecular docking, molecular dynamics simulation, 3D-QSAR model, TOPKAT method, and VEGA platform. Finally, the potential environmental risk (phytotoxicity) and human health risks (neurotoxicity, immunotoxicity, genotoxicity, carcinogenicity, developmental toxicity, and endocrine-disrupting toxicity) during PAHs metabolism and transformation were comprehensively evaluated. Among the 473 PAH's metabolized and transformed products, all PAHs by-products excluding ACY, CHR, and DahA had higher neurotoxicity, 152 PAHs by-products had higher immunotoxicity, and 222 PAHs by-products had higher phytotoxicity than their precursors during biological metabolism and environmental transformation. Based on the TOPKAT model, 152 PAH by-products possessed potential developmental toxicity, and 138 PAH by-products had higher genotoxicity than their precursors. VEGA predicted that 247 kinds of PAH derivatives had carcinogenic activity, and only the natural transformation products of ACY did not have carcinogenicity. In addition to ACY, 15 PAHs produced 123 endocrine-disrupting substances during metabolism and transformation. Finally, the potential environmental and human health risks of PAHs metabolism and transformation products were evaluated using metabolic and transformation pathway probability and degree of toxic risk as indicators. Accordingly, the priority control strategy for PAHs was constructed based on the risk entropy method by screening the priority control pathways. This paper assesses the potential human health and environmental risks of PAHs in different environmental media with the help of models and toxicological modules for the toxicity prediction of PAHs by-products, and thus designs a risk priority control evaluation system for PAHs.

Polycyclic aromatic hydrocarbon exposure and DNA oxidative damage of workers in workshops of a petrochemical group

The petrochemical industry has promoted the development of economy, while polycyclic aromatic hydrocarbons (PAHs) produced by the industry become the threat for environment and humans. Data on human occupational exposure in petrochemical industry are limited. In the present study, urinary hydroxylated PAH metabolites (OH-PAHs) and a biomarker of DNA oxidative damage (8-hydroxy-2'-deoxyguanosine (8-OHdG)) were measured in 546 workers of a petrochemical group in Northeast China, to investigate PAH exposure and related potential health risk. The concentrations of ∑₉OH-PAH in all workers were 0.25-175 μg/g Cre with a median value of 4.41 μg/g Cre. Metabolites of naphthalene were the predominant compounds. The levels of PAH metabolites were significantly different for workers with different jobs, which were the highest for recycling workers (13.7 μg/g Cre) and the lowest for agency managers (5.12 μg/g Cre). Besides, higher levels of OH-PAHs were usually found in males and older workers. There was a dose-response relationship between levels of 8-OHdG and ∑₉OH-PAHs (p < 0.01). No difference was observed in concentrations of 8-OHdG for workers of different gender or ages, work history as well as noise. Furthermore, workers simultaneously exposed to other potential pollutants and higher levels of ∑₉OH-PAH had significantly higher levels of 8-OHdG compared with those in the corresponding subgroups. Our results suggested that exposure to PAHs or co-exposure to PAHs and potential toxics in the petrochemical plant may cause DNA damage. We call for more researches on the associations among noise, chemical pollution and oxidative stress to workers in the real working environment.

The Association between Urinary Polycyclic Aromatic Hydrocarbons Metabolites and Type 2 Diabetes Mellitus

Polycyclic aromatic hydrocarbons (PAHs) are considered to be endocrine disruptors. In this study, the evidence on the association between PAHs and diabetes was systematically reviewed. PubMed, EMBASE, and ISI Web of Science were systematically searched for studies reporting the association between PAHs and diabetes. Of the 698 articles identified through the search, nine cross-sectional studies were included. Seven were conducted in the general population and two in coke oven workers. Fixed-effects and random-effects models were used to calculate the total effect. Subgroup analysis was further carried out according to the types of PAH metabolites. The results showed that the odds of diabetes were significantly higher for the highest category of urinary naphthalene (NAP), fluorine (FLU), phenanthrene (PHEN), and total mono-hydroxylated (OH-PAH) metabolites compared to the lowest category. The pooled odds ratios (OR) and 95% confidence intervals (CI) were 1.52 (95%CI: 1.19, 1.94), 1.53 (95%CI: 1.36, 1.71), 1.43 (95%CI: 1.28, 1.60), and 1.49 (95%CI: 1.07, 2.08), respectively. In coke oven workers, 4-hydroxyphenanthrene (4-OHPh) was significantly correlated with an increased risk of diabetes. Exposure measurements, outcome definitions, and adjustment for confounders were heterogeneous between studies. The results of the current study demonstrate a potentially adverse effect of PAHs on diabetes. Further mechanistic studies and longitudinal studies are needed to confirm whether PAH metabolite levels are causative, and hence associative, with increased diabetes incidences.

A Machine Learning Based Framework to Identify and Classify Non-alcoholic Fatty Liver Disease in a Large-Scale Population

Non-alcoholic fatty liver disease (NAFLD) is a common serious health problem worldwide, which lacks efficient medical treatment. We aimed to develop and validate the machine learning (ML) models which could be used to the accurate screening of large number of people. This paper included 304,145 adults who have joined in the national physical examination and used their questionnaire and physical measurement parameters as model's candidate covariates. Absolute shrinkage and selection operator (LASSO) was used to feature selection from candidate covariates, then four ML algorithms were used to build the screening model for NAFLD, used a classifier with the best performance to output the importance score of the covariate in NAFLD. Among the four ML algorithms, XGBoost owned the best performance (accuracy = 0.880, precision = 0.801, recall = 0.894, F-1 = 0.882, and AUC = 0.951), and the importance ranking of covariates is accordingly BMI, age, waist circumference, gender, type 2 diabetes, gallbladder disease, smoking, hypertension, dietary status, physical activity, oil-loving and salt-loving. ML classifiers could help medical agencies achieve the early identification and classification of NAFLD, which is particularly useful for areas with poor economy, and the covariates' importance degree will be helpful to the prevention and treatment of NAFLD.

Association of chronic kidney disease with exposure to polycyclic aromatic hydrocarbons in the US population

Polycyclic aromatic hydrocarbons (PAHs) are environmental pollutants formed from the incomplete combustion of carbon-containing products. Exposure can occur through ingestion or inhalation and has been linked to depression, stroke, liver disease, asthma, diabetes, heart failure, and cancer. Few studies have investigated the association between exposure to PAHs and chronic kidney disease (CKD) in humans. This study aims to investigate the association between seven urinary PAH concentrations (1-hydroxynaphthalene, 2-hydroxynaphthalene, 3-hydroxyfluorene 2-hydroxyfluorene, 1-hydroxyphenanthrene, 1-hydroxypyrene, and 2 & 3-hydroxyphenanthrene) and CKD in the US adult population. A cross-sectional analysis using the 2015-2016 National Health and Nutrition Examination Survey (NHANES) dataset was conducted. CKD was defined with estimated glomerular filtration rate (eGFR) and albumin to creatinine ratio (ACR). Participants with an eGFR < 60 ml/min/1.73m² or ACR > 30 mg/gm were considered to have CKD. A specialized complex survey design analysis package using R version 4.0.3 was used in the data analysis. Multivariate logistic regression was used to study the correlation between seven forms of urinary PAH concentrations and CKD associated with abnormal eGFR or ACR. The models were adjusted for lifestyle and demographic factors. The study included a total of 4117 adults aged ≥ 20 years, with 49.6% males and 50.4% females. Urinary 2-hydroxynaphthalene (OR: 1.600, 95% CI: 1.141, 2.243) was significantly associated with an increased odds of CKD; the other six forms of urinary PAHs were not associated with CKD. Non-Hispanic Black (OR: 1.569, 95% CI: 1.168, 2.108), age of 60 years and older (OR: 2.546, 95% CI: 1.865, 3.476), and BMIs of underweight (OR: 2.386, 95% CI: 1.259, 4.524) and obese (OR: 1.407, 95% CI: 1.113, 1.778) all had significantly increased odds for CKD. Our study concluded that urinary 2-hydroxynaphthalene, a form of PAH, is significantly associated with CKD.

Environmental chemical exposure dynamics and machine learning-based prediction of diabetes mellitus

BACKGROUND

With dramatically increasing prevalence, diabetes mellitus has imposed a tremendous toll on individual well-being. Humans are exposed to various environmental chemicals, which have been postulated as underappreciated but potentially modifiable diabetes risk factors.

OBJECTIVES

To determine the utility of environmental chemical exposure in predicting diabetes mellitus.

METHODS

A total of 8501 eligible participants from NHANES 2005-2016 were randomly assigned to a discovery (N = 5953) set and a validation (N = 2548) set. We applied random forest (RF) and least absolute shrinkage and selection operator (LASSO) regression with 10-fold cross-validation in the discovery set to select features, and built an optimal model to predict diabetes mellitus, blood insulin, fasting plasma glucose (FPG) and 2-h plasma glucose after oral glucose tolerance test (2-h PG after OGTT).

RESULTS

The machine learning model using LASSO regression predicted diabetes with an area under the receiver operating characteristics (AUROC) of 0.80 and 0.78 in the discovery set and validation set, respectively. The linear model predicted blood insulin level with an R2 of 0.42 and 0.40 in the discovery set and validation set, respectively. For FPG, the discovery set and validation set yielded an R2 of 0.16 and 0.15, respectively. For 2-h PG after OGTT, the discovery set and validation set yielded an R2 of 0.18 and 0.17, respectively.

CONCLUSION

We used environmental chemical exposure, constructed machine learning models and achieved relatively accurate prediction for diabetes, emphasizing the predictive value of widespread environmental chemicals for complicated diseases.

Effects of Environmental Polycyclic Aromatic Hydrocarbons Exposure and Pro-Inflammatory Activity on Type 2 Diabetes Mellitus in US Adults

Polycyclic aromatic hydrocarbons (PAHs) are formed due to natural and anthropogenic activities and known for their potential impact and persistence in the environment. PAHs exposure has been linked to cause adverse health effect including lung cancer, heart conditions and genetic mutations. The understanding of metabolic effects of PAHs exposure is less clear especially in the presence of pro-inflammatory stress like alcoholism or diabetes. The aim of this article is to understand the metabolic effects of PAHs exposure on Type 2 Diabetes Mellitus (T2DM) by analyzing the clinical biomarkers data retrieved from the National Health and Nutrition Examination Survey, Center for Disease Control (CDC NHANES) (2015–16). This study has also accessed the interactive impact of PAHs and other proinflammatory factors, like alcohol intake on the metabolic syndrome on T2DM. We investigated urinary levels of hydroxylated PAHs metabolites (OH-PAHs) along with demographic, clinical and laboratory data. Generalize linear model Univariate factorial ANOVA was used to evaluate the group differences in the demographics, PAH exposure, drinking patterns, clinical data, and biomarker levels. Linear regression model was used to analyze the association of biomarkers, PAH exposure and drinking data. Multivariable regression model was used for multi-independent model to assess comorbidity association and their effect sizes on the clinical outcomes. The results indicated that BMI (p = 0.002), and age (≤0.001) are independent demographic risk factors for T2DM in high PAHs exposure. Acute proinflammatory activity characterized by CRP, is augmented by elevated monocyte levels (p ≤ 0.001) and stepwise addition of 1-Hydroxynapthelene (p = 0.005), and 2-Hydroxynapthelene (p = 0.001) independently. Prevalence of highest average drinks over time is observed in the high PAHs exposure; with males drinking almost twice compared to females in highly exposed population. Pathway response of T2DM shows sexual dimorphism; with males showing association with triglycerides (p ≤ 0.001), and females with CRP (p = 0.015) independently with HbA1C. The arrangement of CRP, absolute monocyte levels, serum triglycerides and average drinks over time predict the HbA1C levels (adjusted R² = 0.226, p ≤ 0.001) in individuals with high PAHs exposure. Findings from this investigation support the pathological role of high exposure of PAHs in the exacerbation of metabolic disorder syndrome involving T2DM. Sexual dimorphism is reflected in alcohol drinking, with males drinking more in the high PAHs exposure group. Alcohol drinking as an independent factor was associated with the T2DM indicator, HbA1C in individuals with high PAHs exposure.

Exposure to polycyclic aromatic hydrocarbons and volatile organic compounds is associated with a risk of obesity and diabetes mellitus among Korean adults: Korean National Environmental Health Survey (KoNEHS) 2015-2017

Environmental pollutants have been known to increase the risks of not only respiratory and cardiovascular disease but also metabolic diseases such as obesity and diabetes mellitus (DM). Polycyclic aromatic hydrocarbons (PAHs) and volatile organic compounds (VOCs) such as benzene and toluene are major constituents of environmental pollution. In the present study, we employed the population of the Korean National Environmental Health Survey (KoNEHS) Cycle 3 conducted between 2015 and 2017, and assessed the associations of urinary biomarkers for PAHs and VOCs exposure with obesity and DM. A total of 3787 adult participants were included and the urinary concentrations of four PAH metabolites and two VOC metabolites were measured. For correcting urine dilution, a covariate-adjusted standardization method was used. The highest quartiles of urinary 2-hydroxynaphthalene (2-NAP) [OR (95% confidence interval (CI)) = 1.46 (1.13, 1.87)] and sum of PAH metabolites [OR (95% CI) = 1.45 (1.13, 1.87)] concentrations were associated with a higher risk of obesity [body mass index (BMI)≥25 kg/m²]. BMI was positively associated with urinary 2-NAP [β (95% CI) = 0.25 (0.09, 0.41), p = 0.003] and sum of PAH metabolites [β (95% CI) = 0.29 (0.08, 0.49), p = 0.006] concentrations. The risk of DM was increased with increasing quartile of 2-hydroxyfluorene (2-OHFlu) and trans, trans-muconic acid (t,t-MA) (p for trend<0.05 and < 0.001, respectively). The highest quartile of t,t-MA showed a significantly higher risk of DM [OR (95% CI) = 2.77 (1.74, 4.42)] and obesity [OR (95% CI) = 1.42 (1.06, 1.90)]. Urinary t,t,-MA level was positively associated with BMI [(β (95% CI) = 0.51 (0.31, 0.71), p < 0.001] and non-alcoholic fatty liver disease index [(β (95% CI) = 0.09 (0.06, 0.12), p < 0.001]. In conclusion, the benzene metabolites t,t-MA and PAH metabolite 2-OHFlu were associated with an increased risk of DM. Urinary biomarkers for PAHs and VOCs were positively associated with BMI in the Korean adult population. Further studies to validate these observations in other populations are warranted.

Particle-bound PAHs induced glucose metabolism disorders through HIF-1 pathway

Vehicle exhaust, as one of the most important compositions of air pollution, induced various adverse health effects, especially diabetes, on human beings. Even though monitoring and epidemiological data indicates that particle-bound polycyclic aromatic hydrocarbons (PAHs) is an inducing factor of diabetes, the specific causative mechanisms are still unclear. In the current study, the concentration of particulate matters (PMs, including PM_1.0, PM_2.5 and PM_10.0) and PAHs was investigated at rush hour of weekday in three urban underground parking garages (UPGs). To evaluate the impacts of particle-bound PAHs on human beings, analysis of non-target metabolomics and unmetabolized PAHs were conducted for UPG and non-UPG worker urine samples. The results showed that the highest concentrations of PMs and total PAHs were found at the UPG entrance. The concentrations of unmetabolized 5-6 rings PAHs in the UPG worker urine were significantly higher than that in non-UPG worker urine samples, which induced glucose metabolism disorders through hypoxia-inducible factor 1 (HIF-1) signaling pathway. This could be a reason for particle-bound PAHs induced-diabetes on road workers, drivers and garage staff. These findings can serve as a step towards air pollution management and the pathological mechanism analysis of environmental factor induced-diseases.

Stress hormone biosynthesis-based genes and lifestyle moderated the association of noise exposure with blood pressure in a cohort of Chinese tobacco factory workers: A cross-sectional analysis

When evaluating noise-related cardiovascular risk, noise is generally solely assessed as the major stressor. However, cardiovascular effect of other simultaneous exposure events, such as unhealthy lifestyle and genetic variation, is easily neglected. The aim of this study is to estimate the combined effect of noise and lifestyle on blood pressure alteration, particularly under different genetic background. This study included 536 workers from a tobacco factory in Wuhan, China, who were divided into high exposure group and low exposure group according to noise measurement in their working area. All participants took annual physical examination and questionnaire survey to provide information on individual systolic and diastolic blood pressure (SBP and DBP) and lifestyle (smoking, drinking and physical activity). Single nucleotide polymorphism at genes related to stress hormone production were determined. Moderated moderation models were constructed to investigate the interaction effect of noise exposure and lifestyle factors on blood pressure with regard to different genetic background. We identified an expected trend in association between noise exposure and SBP among active smokers (P = 0.086). The moderated moderation analysis showed significant three-way interaction effect (COMT rs4680 × smoking status × noise exposure levels) on SBP or DBP (both P < 0.05). For COMT rs4680 GA+AA genotype carriers, active smoking significantly moderated the association between noise exposure and SBP or DBP (both P < 0.05). The results indicated that for COMT rs4680 A allele carriers, tobacco and noise exposure contribute collectively to blood pressure alteration, supporting that stress hormone production may play a certain role in the smoke-and-noise-induced cardiovascular effect.

The methylation of the AMER3 gene mediates the negative association between urinary polycyclic aromatic hydrocarbon metabolites and fasting plasma glucose in non-smokers: A new clue for the development of hypoglycemic agents

Polycyclic aromatic hydrocarbons (PAHs) have been reported to cause various health damages. However, some PAH derivatives are still used as agents, and some of them have hypoglycemic effects. Till now, few studies explored the relationship between urinary PAH metabolites and fasting plasma glucose (FPG). In this study, A total of 2682 non-smokers in the second follow-up of the Wuhan-Zhuhai cohort were included to explore the relationship between urinary PAH metabolites and FPG. FPG related epigenome-wide association study (EWAS) was conducted among 212 never smokers, and the mediation analysis was performed to find potential mediator cytosine-phosphoguanine (CpG) sites in the above relationship. The concentration of total urinary PAH metabolites was 3.60 (2.37, 5.85) μg/mmol Cr. The urinary PAH metabolites were negatively associated with FPG. Each 1-U increase in ln-transformed levels of 1-hydroxynaphthalene, 4-hydroxyphenanthrene, 9-hydroxyphenanthrene, or 2- hydroxyphenanthrene was associated with 0.008-, 0.007-, 0.010-, or 0.010- unit decreased in ln-transformed levels of FPG, respectively (all p < 0.05). We found 28 new CpG sites related to FPG (FDR <0.05) through EWAS. Mediation analysis found that cg11350141 on AMER3 mediated 41.91% of the negative association of total urinary PAH metabolites with FPG. These results provide a new clue for the development of hypoglycemic agents.

Evaluation of hydroxylated metabolites of polycyclic aromatic hydrocarbons and biomarkers of early kidney damage in indigenous children from Ticul, Yucatán, Mexico

Polycyclic aromatic hydrocarbons (PAHs) are environmental persistent chemicals, produced by the incomplete combustion of solid fuels, found in smoke. PAHs are considered carcinogenic, teratogenic, and genotoxic. Children are susceptible to environmental pollutants, particularly those living in high-exposure settings. Therefore, the main objective of this study was to evaluate the exposure to PAHs through hydroxylated metabolites of PAHs (OH-PAHs), 1-hydroxynaphtalene (1-OH-NAP), and 2-hydroxynaphtalene (2-OH-NAP); 2-,3-, and 9-hydroxyfluorene (2-OH-FLU, 3-OH-FLU, 9-OH-FLU); 1-,2-,3-, and 4-hydroxyphenanthrene (1-OH-PHE, 2-OH-PHE, 3-OH-PHE, 4-OH-PHE); and 1-hydroxypyrene (1-OH-PYR), as well as kidney health through biomarkers of early kidney damage (osteopontin (OPN), neutrophil gelatinase-associated lipocalin (NGAL), α1-microglobulin (α1-MG), and cystatin C (Cys-C)) in children from an indigenous community dedicated to footwear manufacturing and pottery in Ticul, Yucatán, Mexico. The results show a high exposure to PAHs from the found concentrations of OH-PAHs in urine in 80.5% of the children in median concentrations of 18.4 (5.1-71.0) μg/L of total OH-PAHs, as well as concentrations of kidney damage proteins in 100% of the study population in concentrations of 4.8 (3-12.2) and 7.9 (6.5-13.7) μg/g creatinine of NGAL and Cys-C respectively, and 97.5% of the population with concentrations of OPN and α1-MG at mean concentrations of 207.3 (119.8-399.8) and 92.2 (68.5-165.5) μg/g creatinine. The information provided should be considered and addressed by the health authorities to establish continuous biomonitoring and programs to reduce para-occupational exposure in the vulnerable population, particularly children, based on their fundamental human right to health.

E-waste polycyclic aromatic hydrocarbon (PAH) exposure leads to child gut-mucosal inflammation and adaptive immune response

Polycyclic aromatic hydrocarbon (PAH) exposure alters immunological responses. Research concerning PAH exposure on intestinal immunity of children in electronic waste (e-waste) areas is scarce. The aim of this study was to evaluate the effects of polycyclic aromatic hydrocarbon (PAH) pollutants on intestinal mucosal immunity of children in e-waste areas. Results showed higher hydroxylated PAH (OH-PAH) concentrations in e-waste-exposed children, accompanied with higher sialyl Lewis A (SLA) level, absolute lymphocyte and monocyte counts, decreased of percentage of CD4⁺ T cells, and had a higher risk of diarrhea. OH-PAH concentrations were negative with child growth. 1-OHNap mediated through WBCs, along with 1-OHPyr, was correlated with an increase SLA concentration. 2-OHFlu, 1-OHPhe, 2-OHPhe, 1-OHPyr, and 6-OHChr were positively correlated with secretory immunoglobulin A (sIgA) concentration. Our results indicated that PAH pollutants caused inflammation, affected the intestinal epithelium, and led to transformation of microfold cell (M cell). M cells initiating mucosal immune responses and the subsequent increasing sIgA production might be an adaptive immune respond of children in the e-waste areas. To our knowledge, this is the first study of PAH exposure on children intestinal immunity in e-waste area, showing that PAH exposure plays a negative role in child growth and impairs the intestinal immune function.

Systematic Review of Exposure to Polycyclic Aromatic Hydrocarbons and Obstructive Lung Disease

BACKGROUND

There is fast-growing epidemiologic evidence of the effects of environmental chemicals on respiratory health. Polycyclic aromatic hydrocarbons (PAHs) have been linked with airway obstruction common in asthma and/or asthma exacerbation, and chronic bronchitis and emphysema.

OBJECTIVES

A systematic review of the association between exposure to PAHs and obstructive lung diseases is not yet available. The present systematic review aims to evaluate the evidence available in epidemiological studies that have associated PAHs with obstructive lung diseases such as asthma, chronic bronchitis, emphysema.

METHODS

We performed a systematic literature search on PubMed, Google Scholar, and Scopus databases using relevant keywords and guided by predesigned eligibility criteria.

RESULTS

From the total of 30 articles reviewed, 16 articles examined the link between PAHs and lung function in both adults and children. Twelve articles investigated the association between PAHs and asthma, asthma biomarkers, and/or asthma symptoms in children. Two articles studied the relationship between PAHs and fractional exhaled nitric oxide (FeNO), a biomarker of airway inflammation and the relationship between PAHs and obstructive lung diseases and infections, respectively. One study assessed exposure to daily ambient PAHs and cough occurrence.

DISCUSSION

Twenty-seven studies found an association between PAHs and asthma and reduced lung function. In children it is reinforced by studies on prenatal and postnatal exposure, whereas in adults, reductions in lung function tests marked by low forced expiratory volume in 1 second, (FEV₁), forced vital capacity (FVC), and forced expiratory flow (FEF_25-75%) were the major health outcomes. Some studies recorded contrasting results: insignificant and/or no association between the two variables of interest. The studies reviewed had limitations ranging from small sample size, to the use of cross-sectional rather than longitudinal study design.

CONCLUSIONS

The literature reviewed in the present study largely suggest positive correlations between PAHs and obstructive lung diseases marked mainly by asthma and reduced respiratory function. This review was registered with PROSPERO (Registration no: CRD42020212894).

COMPETING INTERESTS

The authors declare no competing financial interests.

Environmental pollution and diabetes mellitus

Diabetes mellitus (DM) is a chromic metabolic disease that affects a large segment of the population worldwide. Physical inactivity, poor nutrition, and genetic predisposition are main risk factors for disease development. In the last decade, it was clear to the scientific community that DM development is linked to a novel disease inducer that was later defined as diabetogenic factors of pollution and endocrine disrupting agents. Environmental pollution is exponentially increasing in uncontrolled manner in several countries. Environmental pollutants are of diverse nature and toxicities, including polyaromatic hydrocarbons (PAHs), pesticides, and heavy metals. In the current review, we shed light on the impact of each class of these pollutants and the underlined molecular mechanism of diabetes induction and biological toxicities. Finally, a brief overview about the connection between coronavirus disease 2019 and diabetes pandemics is presented.

Subgroup analysis of the relationship between polycyclic aromatic hydrocarbons and rheumatoid arthritis: Data from the National Health and Nutrition Examination Survey, 2003-2014

The present study examined potential effect modifiers between polycyclic aromatic hydrocarbon (PAH) exposure and the development of rheumatoid arthritis (RA) and elucidated the relationship between PAHs and RA in subgroups using data from the National Health and Nutrition Examination Survey (NHANES) (2003-2014). The relatedness between eight PAH metabolites and RA in the whole population and different subgroups was tested using multivariable logistic regression analyses. This study included 6297 participants, including 400 RA patients and 5897 non-RA control participants, with full data. Compared to the lowest quartiles, risk of RA was increased in population with the highest quartiles of 1-hydroxynaphthalene (1-NAP), 2-NAP, 2-hydroxyfluorene (2-FLU), and 3-FLU in a bias factor corrected model. The associations between urinary PAH metabolites and RA were prominent in female, young and middle-aged, obese, smoking and alcohol-consuming populations in the subgroup analysis. Our results demonstrated that PAH exposure was related to RA, and the relationship between urinary PAH metabolites and RA differed between subgroups and depended on specific PAH metabolites.

Polycyclic Aromatic Hydrocarbons and the Risk of Kidney Stones in US Adults: An Exposure-Response Analysis of NHANES 2007-2012

Background

Polycyclic aromatic hydrocarbons (PAHs) exposure may cause various diseases. However, the association between PAHs exposure and kidney stones remains unclear. The purpose of this study was to examine the relationship between PAHs and the risk of kidney stones in the US population.

Methods

The study included a total of 30,442 individuals (≥20 years) from the 2007–2012 National Health and Nutrition Examination Survey (NHANES). Nine urinary PAHs were included in this study. Logistic regression and dose–response curves were used to evaluate the association between PAHs and the risk of kidney stones.

Results

We selected 4385 participants. The dose–response curves showed a significant positive association between total PAHs, 2-hydroxynaphthalene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 9-hydroxyfluorene and the risk of kidney stones after adjusting for confounding factors. Compared with the low group, an increased risk of kidney stones was observed in the high group of total PAHs [OR (95% CI), 1.32 (1.06–1.64), P=0.013], 2-hydroxynaphthalene [OR (95% CI), 1.37 (1.10–1.71), P=0.005], 1-hydroxyphenanthrene [OR (95% CI), 1.24 (1.00–1.54), P=0.046] and 9-hydroxyfluorene [OR (95% CI), 1.36 (1.09–1.70), P=0.007].

Conclusion

High levels of PAHs were positively associated with the risk of kidney stones in the US population.

In utero exposure to phenanthrene induced islet cell dysfunction in adult mice: Sex differences in the effects and potential causes

Epidemiological studies show that the burden of polycyclic aromatic hydrocarbons in human body is associated with the occurrence of insulin resistance and diabetes. In the present study, pregnant mice were exposed to phenanthrene (Phe) at doses of 0, 60 and 600 μg/kg body weight of by gavage once every 3 days. The female F1 mice at 120 days of age showed no change in their fasting glucose levels (FGLs) but exhibited significantly decreased homeostasis model assessment (HOMA) β-cell (49% and 43%) and significantly downregulated pancreatic proinsulin gene (ins2) transcription. The downregulation of transcription factors, such as PDX1, PAX4 and FGF21, indicated impaired development and function of β-cells. The significantly reduced α-cell mass in 60 and 600 μg/kg groups, and the significantly downregulated expression of proglucagon gene gcg and ARX in the 600 μg/kg group suggested that the development and function of α-cells had been impacted. The males exhibited significantly increased FGLs (1.14- and 1.15-fold) in Phe exposed treatments and significantly elevated HOMA β-cell (3.15-fold) in the 600 μg/kg group. Upregulated ins2 transcription and FGF21 protein in male mice prenatally exposed to 600 μg/kg Phe suggested that these animals appeared compensatory enhancement in β-cell function. The reduced serum estradiol levels and downregulated pancreatic estrogen receptor α and β were responsible for the dysfunction of β-cells in the females. In the males, the significantly elevated androgen levels in the 600 μg/kg group might be related to the upregulated ins2 transcription, and the increased expression of pancreatic FGF21 further demonstrated the enhancement of β-cell potential. The results will be helpful for assessing the risk of developing diabetes in adulthood after prenatal exposure to phenanthrene.

Maternal exposure to phenanthrene during gestation disturbs glucose homeostasis in adult mouse offspring

Epidemiological studies have indicated that polycyclic aromatic hydrocarbons were related to diabetes and insulin resistance. However, studies in mammals on the development of diabetes caused by polycyclic aromatic hydrocarbons are lacking. Pregnant mice were orally exposed to phenanthrene (0, 60 and 600 μg kg^-1 body weight) once every 3 days during gestation. In adult mouse offspring, in-utero phenanthrene exposure caused glucose intolerance and decreased insulin levels in females, while caused elevated fasting blood glucose and insulin levels in males. Serum resistin and interleukin-6 levels were elevated in offspring of both sexes. Serum adiponectin levels were decreased in females but increased in males. The insulin receptor signals were upregulated in the liver and downregulated in the skeletal muscle of F1 females, while they were inhibited in both tissues of F1 males. The visceral fat weight and body weight of the treated mice were not increased, suggesting that phenanthrene is not an obesogen, which is supported by the nonsignificant alteration in pparγ transcription in visceral adipose tissue. The transcription of retn in visceral adipose tissue was upregulated in both sexes, and that of adipoq was downregulated in females but upregulated in males, which were matched with the promoter methylation levels of these genes. The results indicated that phenanthrene exposure during gestation could disturb adipocytokine levels via epigenetic modification in adult offspring, and further influence glucose metabolism. These results might be helpful for understanding nonobesogenic pollutant-induced insulin resistance and preventing against diabetes without obesity.

Telomere length mediates the association between polycyclic aromatic hydrocarbons exposure and abnormal glucose level among Chinese coke oven plant workers

INTRODUCTION

Diabetes is a chronic and complex disease determined by environmental and genetic factors. This study aimed to investigate the association between polycyclic aromatic hydrocarbons (PAHs) exposure and fasting blood glucose levels and telomere length among coke-oven plant workers, to explore potential role of telomere length (TL) in the association between PAHs exposure and abnormal glucose level.

METHODS

The cross-sectional survey was conducted in 2017. The high-performance liquid chromatography mass spectrometry (HPLC-MS) was used to detect 11 urine biomarkers of PAHs exposure. TL was measured using the Real-time quantitative polymerase chain reaction (RT-qPCR) method. Logistic regression model, the modified Poisson regression models, and mediation analysis were used to evaluate the associations between PAHs exposure, TL, and abnormal glucose.

RESULTS

The results showed that the urinary 1-hydroxypyrene (1-PYR) was positively related to abnormal glucose in a dose-dependent manner (P_trend = 0.007), the prevalence ratio of abnormal glucose was 8% (95% CI: 1.01-1.16) higher in 3rd tertile of urinary 1-PYR levels. Urinary 1-PYR in the 2nd tertile and 3rd tertile were associated with a 53% (OR = 0.47, 95% CI: 0.28-0.79) and 59% (OR = 0.41, 95% CI: 0.23-0.76) higher risk of shortening TL. And there was a negatively association between 1-PYR and TL in a dose-dependent manner (P_trend = 0.045). We observed that the association between 1-PYR and abnormal glucose was more significantly positive among participants with median TL level (P_trend = 0.006). In addition, mediation analysis showed the TL could explain 11.7% of the effect of abnormal glucose related to PAHs exposure.

CONCLUSIONS

Our findings suggested the effect of abnormal glucose related to PAHs exposure was mediated by telomere length in coke oven plant workers.

Relationship between urinary metabolites of polycyclic aromatic hydrocarbons and risk of papillary thyroid carcinoma and nodular goiter: A case-control study in non-occupational populations

Exposure to polycyclic aromatic hydrocarbons (PAHs) has been linked to the development of certain diseases. However, the relationship between PAH exposure and thyroid disorders remains unknown. We measured 10 of the most common hydroxylated PAHs (OH-PAHs) in the urine of thyroid nodular goiter (NG) patients, papillary thyroid carcinoma (PTC) patients, and healthy controls by gas chromatography-triple-quadrupole mass spectrometry (GC-MS/MS). We found that the concentrations of 2-hydroxyfluorene (2-OH-FLU), 2-hydroxydibenzofuran (2-OH-DBF), and 1-hydroxyphenanthrene (1-OH-PHE) in the NG group, and of 2-hydroxynaphthalene (2-OH-NAP), 2-OH-DBF, and 1-OH-PHE in the PTC group were significantly higher than those in controls. In addition, participants in the high tertiles of 2-OH-FLU and 1-OH-PHE had higher risk of NG. Besides these two OH-PAHs, elevated risk of NG was observed in women in the high tertiles of 1-hydroxynaphthalene (1-OH-NAP), 2-OH-NAP, 2-OH-DBF, and 3-hydroxyfluorene (3-OH-FLU). Furthermore, participants in the high tertiles of seven OH-PAHs, namely, 1-OH-NAP, 2-OH-NAP, 2-OH-DBF, 2-OH-FLU, 3-OH-FLU, 3/9-hydroxyphenanthrene (3/9-OH-PHE), and 1-OH-PHE, had elevated risk of PTC, and females in these high tertiles had an even higher risk of PTC. Our findings suggest that PAH exposure may increase the risk of NG/PTC, and there may be a gender-specific effect of PAH exposure on the development of NG/PTC.

IL-22: A potential mediator of associations between urinary polycyclic aromatic hydrocarbon metabolites with fasting plasma glucose and type 2 diabetes

Previous studies found that exposure to polycyclic aromatic hydrocarbons (PAHs) was associated with type 2 diabetes (T2D) prevalence. However, the potential mechanism is still unclear. In this study, we investigated 3031 Chinese urban adults to discover the relationship between PAH exposure and plasma Interleukin-22 (IL-22) and potential role of IL-22 in the association between PAH and fasting plasma glucose (FPG) or risk of T2D. After adjustment for potential confounders, significant dose-response relationships were observed between several urinary PAH metabolites with FPG and the prevalence of T2D. Each 1-U increase in ln-transformed value of 2-hydroxynaphthalene (2-OHNa), 2-hydroxyphenanthrene (2-OHPh), 3-hydroxyphenanthrene (3-OHPh), 4-hydroxyphenanthrene (4-OHPh), 9-hydroxyphenanthrene (9-OHPh), 1-hydroxypyrene (1-OHP) or total PAH metabolites was significantly associated with a 0.053, 0.026, 0.037, 0.045, 0.051, 0.041 or 0.047 unit decrease in IL-22 level, respectively. In addition, plasma IL-22 level was negatively associated with FPG and prevalence of T2D in a dose-dependent manner. Mediation analysis showed that IL-22 mediated 8.48 %, 3.87 %, 6.64 %, 6.47 %, and 8.67 % of the associations between urinary 2-OHNa, 1-OHPh, 3-OHPh, 4-OHPh, and 9-OHPh with the prevalence of T2D, respectively. These results indicated that urinary PAHs metabolites were inversely associated with plasma levels of IL-22, but positively related to FPG and the T2D prevalence. Downregulation of IL-22 might play a significant role in mediating PAHs exposure-associated risk increasement of T2D.

Chronic Exposure to Environmental Level Phenanthrene Induces Non-Obesity-Dependent Insulin Resistance in Male Mice

Epidemiological evidence shows that the body burden of polycyclic aromatic hydrocarbons (PAHs) is related to the disruption of glucose homeostasis. However, the contribution of PAHs to the development of diabetes remains poorly documented. In the current work, male Kunming mice received phenanthrene (Phe) (5, 50, and 500 ng/kg) by gavage administration once every 2 days for 28 weeks. The significant elevation of homeostasis model assessment-insulin resistance (HOMA-IR) and HOMA-β cell, accompanied by hyperinsulinemia, indicated the occurrence of insulin resistance. The suppression of the insulin receptor signaling pathway in skeletal muscle might be responsible for glucose intolerance. Under the nonobese state, the serum levels of resistin, tumor necrosis factor-α, and interleukin-6 were elevated, whereas the levels of adiponectin were reduced. These changes in adipocytokine levels were consistent with their transcription in white adipose tissue. The promoter methylation levels of Retn (encoding resistin) and Adipoq (encoding adiponectin) were inversely correlated with their mRNA levels, indicating that Phe exposure could cause the disruption of adipocytokine secretion via epigenetic modification. The results would be helpful for understanding the pathogenesis in the development of T2DM caused by nonobesogenic pollutants.

Contributions of dietary, demographic, disease, lifestyle and other factors in explaining variabilities in concentrations of selected monohydroxylated polycyclic aromatic hydrocarbons in urine: Data for US children, adolescents, and adults

Data from National Health and Nutrition Examination Survey for 2003-2014 for US children aged 6-11 years (N = 2097), adolescents aged 12-19 ears (N = 2642), and adults aged ≥ 20 years (N = 9170) were analyzed to investigate the effects of dietary, demographic, disease, lifestyle, and other factors on concentrations of nine metabolites of polycyclic aromatic hydrocarbons (PAH) in urine. PAHs analyzed were: 1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 9-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, 3-hydroxyphenanthrene, and 1-hydroxypyrene. Adults with diabetes were found to have higher adjusted levels of 1-hydroxynaphthalene (4139 vs. 3622 ng/L, p < 0.01) than nondiabetics. Adults with albuminuria had higher adjusted levels of 1-hydroxynaphthalene (4140 vs.3621 ng/L, p < 0.01) and 2-hydroxynaphthalene (6039 vs. 5468 ng/L, p < 0.01) than those without albuminuria. Children with albuminuria had lower adjusted levels of 9-hydroxyfluorene (162 vs. 187 ng/L, p = 0.04), 1-hydroxyphenanthrene (92 vs. 108 ng/L, p < 0.01), and 1-hydroxypyrene (118 vs. 138 ng/L, p < 0.01) than those without albuminuria. The ratios of smoker to nonsmoker adjusted levels for adults varied from a low of 1.4 for 2-hydroxyphenanthrene to a high of 5.6 for 3-hydroxyfluorene. Exposure to environmental tobacco smoke at home was associated with higher levels of most OH-PAHs among children, adolescents, and adults. Consumption of red meat not processed at high temperatures was associated with increased levels of 1-hydroxypyrene (β = 0.00040, p = 0.01), 1-, 2-, and 3-hydroxyphenanthrene, 3-, and 9-hydroxyfluorene. Consumption of red meat processed at high temperatures was associated with increased levels of 2-hydroxynaphthalene (β = 0.00046, p = 0.02) among adults. Consumption of fish processed at high temperatures was associated with decreased levels of 1-hydroxynaphtahlene (β = - 0.00088, p < 0.01), 2-, 3-, and 9-hydroxyfluorene, 1-, 2-, and 3-hydroxyphenanthrene. Among adults, alcohol consumption and caffeine may be associated with increased levels of certain OH-PAHs. Oxidative stress and inflammation associated with exposure to PAHs are associated with albuminuria and have the potential to lead to the development of diabetes.

Association of internal exposure to polycyclic aromatic hydrocarbons with inflammation and oxidative stress in prediabetic and healthy individuals

Polycyclic aromatic hydrocarbons (PAHs) are key air pollutants that may contribute to the risk of numerous diseases by inducing inflammation and oxidative stress. Individuals with metabolic disorders may be more susceptible to PAH-induced inflammation and oxidative stress. To test this hypothesis, we designed a panel study involving 60 patients with pre-type 2 diabetes (pre-T2D) and 60 reference participants, and conducted up to seven repeated clinical examinations. Urinary metabolites of PAHs (i.e., OH-PAHs), measured as indicators of total PAH exposure, showed significant associations with markers of respiratory and systemic inflammation, including exhaled nitric oxide, interleukin (IL)-6 in exhaled breath condensate, and blood IL-2 and IL-8 levels and leucocyte count. The most significant effect was on urinary malondiadehyde (MDA), a marker of lipid peroxidation; a onefold increase of OH-PAHs was associated with 9.2-46.0% elevation in MDA in pre-T2D participants and 9.8-31.2% increase in healthy references. Pre-T2D participants showed greater increase in MDA, suggesting that metabolic disorder enhanced the oxidative damage induced by PAH exposure. This study revealed the association between PAH exposure and markers of inflammation and oxidative stress, and the enhanced responses of pre-T2D patients suggested that individuals with metabolic disorders were more susceptible to the adverse health effects of PAH exposure.

Oxidative damage mediates the association between polycyclic aromatic hydrocarbon exposure and lung function

BACKGROUND

Exposure to polycyclic aromatic hydrocarbons (PAHs) is related to decreased lung function. However, whether oxidative damage is involved in this relationship remains unclear. This study was aimed to explore the potential mediating role of oxidative DNA or lipid damage in the association between PAH exposure and lung function.

METHODS

The urinary levels of monohydroxy polycyclic aromatic hydrocarbon metabolites (OH-PAHs) and lung function parameters were measured among 3367 participants from the baseline of the Wuhan-Zhuhai cohort. Urinary 8-hydroxy-2'-deoxyguanosine (8-OHdG) and 8-isoprostane (8-iso-PGF2α) were determined to evaluate the individuals' oxidative DNA and lipid damage degrees, respectively. Linear mixed models were used to investigate the associations of urinary OH-PAHs, 8-OHdG and 8-iso-PGF2α with lung function parameters. Mediation analysis was further conducted to assess the potential role of oxidative damage in the association between urinary OH-PAHs and lung function.

RESULTS

Each one-percentage increase in the sum of urinary OH-PAHs, high-molecular-weight or low-molecular-weight OH-PAHs (ƩOH-PAHs, ƩHMW OH-PAH or ƩLMW OH-PAHs, respectively) was associated with a 0.2152-, 0.2076- or 0.1985- ml decrease in FEV₁, and a 0.1891-, 0.2195- or 0.1634- ml decrease in FVC, respectively. Additionally, significantly positive dose-response relationships of ƩOH-PAHs, ƩHMW OH-PAH and ƩLMW OH-PAHs with urinary 8-OHdG or 8-iso-PGF2α, as well as an inverse dose-response relationship between urinary 8-OHdG and FVC, were observed (all P for trend < 0.05). Mediation analysis indicated that urinary 8-OHdG mediated 14.22% of the association between ƩHMW OH-PAH and FVC.

CONCLUSION

Higher levels of oxidative DNA damage might be involved in the decreased levels of FVC caused by high-molecular-weight PAH exposure.

Associations of urinary polycyclic aromatic hydrocarbons with albuminuria in U.S. adults, NHANES 2003-2014

BACKGROUND

Polycyclic aromatic hydrocarbons (PAHs) exposure has been shown to be a risk factor for many diseases. However, studies on the association between PAHs exposure and kidney disease are limited. The aim of this study was to explore the association between urinary PAHs and albuminuria based on a national representative sample from the general U.S.

METHOD

The data utilized were extracted from the 2003-2014 National Health and Nutrition Examination Survey (NHANES). Eight urinary PAHs were detected as PAH metabolites (OH-PAHs). Multivariable logistic regression analyses were applied to examine the association between urinary OH-PAHs and urinary albumin-creatinine ratio (ACR). All models were adjusted for confounding demographic, anthropometric and lifestyle factors.

RESULT

A total of 8149 NHANES (2003-2014) participants with complete data were eligible. Compared with the lowest quartile, an increased prevalence of high ACR level (>3 mg/mmol) was observed in the participants with the highest quartile of 2-hydroxynaphthalene [OR (95% CI), 1.56 (1.28-1.90), P < 0.001], 3-hydroxyfluorene [OR (95% CI), 1.29 (1.06-1.58), P = 0.011] and 2-hydroxyfluorene [OR (95% CI), 1.47 (1.20-1.80), P < 0.001] levels after adjusting for confounding factors. In subgroup analysis, significantly high OH-PAHs leveland a strong relationship between OH-PAHs and ACR were observed in current smokers in the adjusted model.

CONCLUSION

High levels of urinary OH-PAHs were positively associated with high levels of ACR in the U.S.

POPULATION

Our finding provided evidence that PAHs exposure might potentially be related to albuminuria and therefore might have implications for environmental governance and prevention/treatment of this condition.

The association between urinary metabolites of polycyclic aromatic hydrocarbons and diabetes: A systematic review and meta-analysis study

To examine the association between urinary metabolites of polycyclic aromatic hydrocarbons (OH-PAHs) and diabetes, online databases, including PubMed, Scopus, and Web of Science, were searched on July 17, 2019. Of the 668 articles identified through searching, six cross-sectional studies involving 24,406 participants were included. The pooled odds ratio (OR) and 95% confidence interval (CI) were calculated using a random-effect model. Heterogeneity was measured by reporting the I-square index. Moreover, subgroup analysis according to types of metabolites was performed. We found a significantly higher odds of diabetes in the highest versus the lowest category of urinary naphthalene (NAP), fluorine (FLU), phenanthrene (PHEN), and total OH-PAH metabolites. The pooled OR (95% CI) was estimated at 1.47 (1.17, 1.78), 1.50 (1.29, 1.71), 1.41 (1.21, 1.60), and 1.61 (1.01, 2.21), respectively. We also found a significant association per 1-fold increase in FLU (OR = 1.09, 95% CI [1.00, 1.19]) and PHEN (OR = 1.19, 95% CI [1.08, 1.30]) metabolites. In subgroup analysis stratified by types of OH-PAH metabolites, A significant stronger odds of diabetes was observed in the highest versus the lowest category of 2-PHEN (OR = 1.66, 95% CI [1.32, 2.00]), 2-NAP (OR = 1.66, 95% CI [1.16, 2.17]), 2-FLU (OR = 1.62, 95% CI [1.28, 1.97]), and 9-FLU (OR = 1.62, 95% CI [1.21, 2.04]) metabolites. Furthermore, there was a meaningfully greater likelihood of diabetes per 1-fold increase in 2-FLU (OR = 1.34, 95% CI [1.10, 1.57]), 2-PHEN (OR = 1.33, 95% CI [1.14, 1.51]), and 3-PHEN (OR = 1.19, 95% CI [1.04, 1.34]) metabolites. In conclusion, our study suggests the significant odds of association between urinary OH-PAH metabolites and diabetes.

Effects of environmental and lifestyle exposures on urinary levels of polycyclic aromatic hydrocarbon metabolites: A cross-sectional study of urban adults in China

Urinary polycyclic aromatic hydrocarbon (PAH) metabolites, biomarkers of internal PAH exposure, are commonly used to explore the effects of PAH on human health. However, the correlation between environmental PAH exposure and the species or levels of urinary PAH metabolites remains unclear. We collected detailed information on PAH exposure sources, including cigarette smoking, cooking, traffic and diet habits via structured questionnaires, and determined 12 urinary monohydroxylated PAH metabolites (OH-PAHs) among 4092 participants from the Wuhan-Zhuhai cohort. Linear mixed models and generalized linear models were conducted to explore the associations of urinary metabolite levels with single or multiple PAH exposure sources. We also calculated the standardized regression coefficients to further compare the contributions of different sources to urinary OH-PAH levels. Our results showed that increasing levels of urinary 1-, 2-hydroxynaphthalene (1-, 2- OHNa) and 2-hydroxyfluorene (2-OHFlu) were significantly correlated with tobacco smoking (all P < 0.01). The concentrations of 1-, 2- OHNa and 9-hydroxyfluorene (9-OHFlu) were positively correlated with dietary intake (all P < 0.05). Individuals who spent a long time in traffic showed elevated levels of 9-OHFlu and 1-hydroxyphenanthrene (1-OHPh) compared with individuals who spent a short time in traffic (all P < 0.05). Self-cooking was associated only with elevated 1-hydroxypyrene (1-OHP) levels. Moreover, good kitchen ventilation resulted in significantly decreased urinary low-molecular-weight OH-PAH levels. These findings suggested that cigarette smoking, self-cooking, high dietary PAH intake and a long time spent in traffic were associated with increased levels of specific urinary PAH metabolites, and good kitchen ventilation effectively reduced the exposure to low-molecular-weight PAHs in self-cooking participants.