Associations between exposure to polycyclic aromatic hydrocarbons and glucose homeostasis as well as metabolic syndrome in nondiabetic adults

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

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

Association between polycyclic aromatic hydrocarbons and osteoporosis: data from NHANES, 2005-2014

The association between osteoporosis and polycyclic aromatic hydrocarbons was not clear. However, recent studies showed that both osteoporosis and polycyclic aromatic hydrocarbons were associated with reactive oxygen species. So we presumed that polycyclic aromatic hydrocarbons were associated with increased odds of osteoporosis. We found 3-hydroxyfluorene was associated with decreased odds of osteoporosis, while 2-hydroxyfluorene was associated with increased odds of osteoporosis.

PURPOSE

Previous studies showed that polycyclic aromatic hydrocarbons were involved in the production of reactive oxygen species that played an important role in illness. Other studies demonstrated that the reactive oxygen species might play a role in occurrence of osteoporosis. However, the association between polycyclic aromatic hydrocarbons and osteoporosis was not clear. Therefore, we conducted a study to investigate the relationship between polycyclic aromatic hydrocarbons and osteoporosis.

METHODS

A total of 3053 individuals aged 50 years or older were drawn from National Health and Nutritional Examination Survey, 2005-2014. Eight polycyclic aromatic hydrocarbons metabolites (1-hydroxynaphthalene, 2-hydroxynaphthalene, 2-hydroxyfluorene, 3-hydroxyfluorene, 1-hydroxyphenanthrene, 2-hydroxyphenanthrene, and 3-hydroxyphenanthrene and 1-hydroxypyrene) were examined to represent exposure of polycyclic aromatic hydrocarbons in the body. Weighted percentage and weighted mean were used to describe classified variable and continuous variable, respectively. We used weighted logistic regression to estimate the association of polycyclic aromatic hydrocarbons and osteoporosis.

RESULTS

Five hundred seventy-seven (18.9%) osteoporosis patients were included. Among the eight polycyclic aromatic hydrocarbons metabolites, 3-hydroxyfluorene was associated with decreased odds of osteoporosis after controlling socio-demographic status, body mass index, alcohol, previous fracture, parental fracture, glucocorticoid use, dietary calcium intake, smoking, and other polycyclic aromatic hydrocarbons metabolites (OR = 0.63, 95%CI 0.41-0.98). 2-hydroxyfluorene (OR = 1.87, 95%CI 1.07-3.29) was associated with increased odds of osteoporosis. In the nonsmoking group, we found the association of osteoporosis with 2-hydroxyfluorene (OR = 2.56, 95%CI 1.10-5.96) and 3-hydroxyfluorene (OR = 0.41, 95%CI 0.22-0.77) still exists.

CONCLUSION

Our study found that 3-hydroxyfluorene was associated with decreased odd of osteoporosis, while 2-hydroxyfluorene was associated with increased odds of osteoporosis. Our study was a cross-sectional study, therefore cohort studies or experimental studies about association of PAH and osteoporosis is needed.

Exploring the association between polycyclic aromatic hydrocarbons and diabetes among adults in the United States

OBJECTIVE

To explore the association between polycyclic aromatic hydrocarbons (PAHs) and diabetes and to determine whether effects are heterogeneous when examined by body mass index (BMI).

METHODS

Cross-sectional data from 8664 participants were analyzed from the National Health and Nutrition Examination Survey for years 2005-2014. Multivariable logistic regression was used to explore the association between urinary biomarkers of PAHs and diabetes. All models were adjusted for age, sex, race, poverty-income ratio, and serum cotinine.

RESULTS

When compared with the lowest quintiles of exposure, the highest quintiles of exposure to 2-hydroxynaphthalene, 2-hydroxyfluorene, 9-hydroxyfluorene, 2-hydroxyphenanthrene, and a summed variable of all low molecular weight PAHs (aOR = 1.73; 95% CI: 1.17-2.55) showed a positive association with diabetes. Stratified analyses by BMI indicated that the positive association between PAHs and diabetes was found among both normal weight and obese participants.

CONCLUSIONS

High levels of exposure to PAHs are positively associated with diabetes in the U.S. general population and these effects are modified by BMI. These findings suggest the importance of strong environmental regulation of PAHs to protect population health.

Association of polycyclic aromatic hydrocarbons with cardiometabolic risk factors and obesity in children

A limited body of evidence exists on the association of exposure to polycyclic aromatic hydrocarbons (PAHs) with cardiometabolic risk factors and obesity in children. No study has evaluated these associations in subgroups of children with and without excess weight, and those with and without cardiometabolic risk factors. We aimed to investigate the association between PAH exposure and cardiometabolic risk factors in children independent of their weight status. The secondary aim was to evaluate the obesogen properties of PAHs in children independent of their cardiometabolic risk factors. This study was based on a representative sample of 186 children (aged 6-18 years) living in Isfahan, Iran (2014-2016). We enrolled four groups of participants with and without excess weight and with and without cardiometabolic risk factor. Urinary levels of monohydroxy PAHs (OH-PAHs) were measured twice, six months apart. Logistic regression models were developed to estimate the associations of tertiles of urinary OH-PAH concentrations with cardiometabolic risk factors and excess weight, adjusted for the relevant covariates. The findings in all participants combined showed that increased risk of cardiometabolic risk factors and excess weight was associated with exposure to most of evaluated PAHs. Exposure to 1-hydroxypyrene was associated with higher risk of cardiometabolic risk factors in participants with excess weight. Exposure to 2-Naphtol was also associated with higher risk of cardiometabolic risk factors in both groups, but the associations were not significant (p < 0.1). For participants without cardiometabolic risk factors, exposure to 2-naphtol, 9-phenanthrol, and ∑ OH-PAH was associated with increased risk of obesity. For participants with cardiometabolic risk factors, we observed similar pattern of associations for 2-naphtol and ∑ OH-PAH, but the associations were not statistically significant (p < 0.1). We found that exposure to PAHs could possibly explain, in part, the cardiometabolic risk factors in children with excess weight as well as obesity in children with normal cardiometabolic profile.

Traffic-Related Particulate Matter and Cardiometabolic Syndrome: A Review

Traffic-related particulate matter (PM) is a major source of outdoor air pollution worldwide. It has been recently hypothesized to cause cardiometabolic syndrome, including cardiovascular dysfunction, obesity, and diabetes. The environmental and toxicological factors involved in the processes, and the detailed mechanisms remain to be explored. The objective of this study is to assess the current scientific evidence of traffic-related PM-induced cardiometabolic syndrome. We conducted a literature review by searching the keywords of “traffic related air pollution”, “particulate matter”, “human health”, and “metabolic syndrome” from 1980 to 2018. This resulted in 25 independent research studies for the final review. Both epidemiological and toxicological findings reveal consistent correlations between traffic-related PM exposure and the measured cardiometabolic health endpoints. Smaller sizes of PM, particularly ultrafine particles, are shown to be more harmful due to their greater concentrations, reactive compositions, longer lung retention, and bioavailability. The active components in traffic-related PM could be attributed to metals, black carbon, elemental carbon, polyaromatic hydrocarbons, and diesel exhaust particles. Existing evidence points out that the development of cardiometabolic symptoms can occur through chronic systemic inflammation and increased oxidative stress. The elderly (especially for women), children, genetically susceptible individuals, and people with pre-existing conditions are identified as vulnerable groups. To advance the characterization of the potential health risks of traffic-related PM, additional research is needed to investigate the detailed chemical compositions of PM constituents, atmospheric transformations, and the mode of action to induce adverse health effects. Furthermore, we recommend that future studies could explore the roles of genetic and epigenetic factors in influencing cardiometabolic health outcomes by integrating multi-omics approaches (e.g., genomics, epigenomics, and transcriptomics) to provide a comprehensive assessment of biological perturbations caused by traffic-related PM.

Obesity mediated the association of exposure to polycyclic aromatic hydrocarbon with risk of cardiovascular events

Exposure to polycyclic aromatic hydrocarbons (PAHs) could cause high blood pressure (BP) and increased risk for atherosclerotic cardiovascular disease (ASCVD). However, the mechanisms underlying the relationship between them were unclear. We investigated potential mediation effect of obesity on the association of exposure to PAHs with high BP and increased risk for ASCVD. In the repeated measures study, 106 community-dwelling residents in Wuhan, China finished the physical examination in the winter and summer seasons, eight urinary PAHs metabolites were measured. Associations of urinary PAHs with high BP and increased risk for ASCVD were assessed using either linear mixed effect models or generalized estimating equations models. Mediation analysis was performed to evaluate the mediating effect of obesity on the association of urinary PAHs metabolites with high BP or increased risk of ASCVD. We observed the positive association between urinary PAHs metabolites and BP or the odds ratios for high BP (all P<0.05). Additionally, each one-unit increase in ln-transformed urinary levels of 4-hydroxyphenanthrene or the total of PAH metabolites was associated with a 12.63% or 11.91% increase in the estimated 10-year ASCVD risk (both P<0.05). The waist-to-height ratio mediated 29.0% of the association of urinary 4-hydroxyphenanthrene with increased risk of ASCVD (P<0.05). The findings suggest that PAHs exposure may be associated with elevated BP and an increased risk of ASCVD. Obesity may partially mediate the association between PAHs exposure and higher BP or increased risk of ASCVD.

Association of polycyclic aromatic hydrocarbons metabolites and risk of diabetes in coke oven workers

Elevated polycyclic aromatic hydrocarbons (PAHs) metabolites have recently been linked to increased risk of diabetes in the general population, but little is known about the risk of diabetes due to high pollution levels of PAHs exposure. We aimed to examine whether occupational exposure to PAHs would be one of the important risk factors for diabetes in the coke oven workers. A total of 1472 coke oven workers with complete data were qualified for the present study. We measured 12 urinary monohydroxy polycyclic aromatic hydrocarbons (OH-PAHs) by gas chromatography-mass spectrometry (GC-MS). Multiple logistic regression was used to evaluate the associations between urinary OH-PAHs and risk of diabetes, with adjustment for the potential confounders. We found that elevated urinary 4-hydroxyphenanthrene (4-OHPh) was significantly associated, in a dose-dependent manner, with increased risk of diabetes (P_trend = 0.003). Compared with individuals with 4-OHPh in the lowest quartile, the adjusted odds ratio (OR) of diabetes among those in the highest quartile was 2.80 (95% CI = 1.37-5.71). In stratified analysis, the association was more prominent in those who were smokers, overweight (BMI ≥24 kg/m²), with longer working years (≥20 years) and worked at coke oven settings. In addition, high levels of 4-OHPh combined with longer working years or overweight had a joint effect on the risk of diabetes. Our data suggested that elevated 4-OHPh was dose-responsive associated with increased risk of diabetes in the coke oven workers. The risk assessment of diabetes related to occupational PAHs exposure should take working years and BMI into consideration.

Early-life chemical exposures and risk of metabolic syndrome

The global prevalence of obesity has been increasing at a staggering pace, with few indications of any decline, and is now one of the major public health challenges worldwide. While obesity and metabolic syndrome (MetS) have historically thought to be largely driven by increased caloric intake and lack of exercise, this is insufficient to account for the observed changes in disease trends. There is now increasing evidence to suggest that exposure to synthetic chemicals in our environment may also play a key role in the etiology and pathophysiology of metabolic diseases. Importantly, exposures occurring in early life (in utero and early childhood) may have a more profound effect on life-long risk of obesity and MetS. This narrative review explores the evidence linking early-life exposure to a suite of chemicals that are common contaminants associated with food production (pesticides; imidacloprid, chlorpyrifos, and glyphosate) and processing (acrylamide), in addition to chemicals ubiquitously found in our household goods (brominated flame retardants) and drinking water (heavy metals) and changes in key pathways important for the development of MetS and obesity.

Chemopreventive effect of natural dietary compounds on xenobiotic-induced toxicity

Contaminants (or pollutants) that affect human health have become an important issue, spawning a myriad of studies on how to prevent harmful contaminant-induced effects. Recently, a variety of biological functions of natural dietary compounds derived from consumed foods and plants have been demonstrated in a number of studies. Natural dietary compounds exhibited several beneficial effects for the prevention of disease and the inhibition of chemically-induced carcinogenesis. Contaminant-induced toxicity and carcinogenesis are mostly attributed to the mutagenic activity of reactive metabolites and the disruption of normal biological functions. Therefore, the metabolic regulation of hazardous chemicals is key to reducing contaminant-induced adverse health effects. Moreover, promoting contaminant excretion from the body through Phase I and II metabolizing enzymes is also a useful strategy for reducing contaminant-induced toxicity. This review focuses on summarizing the natural dietary compounds derived from common dietary foods and plants and their possible mechanisms of action in the prevention/suppression of contaminant-induced toxicity.

Exposures to road traffic, noise, and air pollution as risk factors for type 2 diabetes: A feasibility study in Bulgaria

Type 2 diabetes mellitus (T2DM) is a growing public health problem in Bulgaria. While individual and lifestyle determinants have been researched; till date there has been no study on environmental risks such as road traffic, noise, and air pollution. As a first step toward designing a large-scale population-based survey, we aimed at exploring the overall associations of prevalent T2DM with exposures to road traffic, noise, and air pollution. A total of 513 residents of Plovdiv city, Bulgaria were recruited. Individual data on self-reported doctor-diagnosed T2DM and confounding factors were linked to objective and self-rated exposure indicators. Logistic and log-link Poisson regressions were conducted. In the fully adjusted logistic models, T2DM was positively associated with exposures to L(den) 71-80 dB (odds ratio (OR) = 4.49, 95% confidence interval (CI): 1.38, 14.68), fine particulate matter (PM) 2.5 25.0-66.8 μg/m 3 (OR = 1.32, 95% CI: 0.28, 6.24), benzo alpha pyrene 6.0-14.02 ng/m 3 (OR = 1.76, 95% CI: 0.52, 5.98) and high road traffic (OR = 1.40, 95% CI: 0.48, 4.07). L(den) remained a significant risk factor in the: Poisson regression model. Other covariates with consistently high multivariate effects were age, gender, body mass index, family history of T2DM, subjective sleep disturbance, and especially bedroom location. We concluded that residential noise exposure might be associated with elevated risk of prevalent T2DM. The inferences made by this research and the lessons learned from its limitations could guide the designing of a longitudinal epidemiological survey in Bulgaria.

Urinary 1-hydroxypyrene concentration as an exposure biomarker to polycyclic aromatic hydrocarbons (PAHs) in Mexican women from different hot spot scenarios and health risk assessment

Recently, in developing countries, polycyclic aromatic hydrocarbons (PAHs) have been considered contaminants of grave concern for women and children. Therefore, the aim of this study was twofold: (1) evaluate exposure assessment to PAHs using urinary 1-hydroxypyrene (1-OHP) as an exposure biomarker and (2) perform a health risk assessment in women from four different high risk scenarios in Mexico. From 2012 to 2013, in a cross-sectional study, we evaluated a total of 184 healthy women from the following scenarios: (A) indoor biomass combustion site (n = 50); (B) brick manufacturing site using different materials such as fuel sources (n = 70); (C) industrial site (n = 44); and (D) high vehicular traffic site (n = 20). 1-hydroxypyrene (1-OHP) was quantified using a high-performance liquid chromatography (HPLC) technique. Afterward, a probabilistic health risk assessment was performed (Monte Carlo analysis). Mean urinary 1-OHP levels found were 0.92 ± 0.92; 0.91 ± 0.83; 0.22 ± 0.19; and 0.14 ± 0.17 μg/L for scenario A, B, C, and D, respectively. Then, based on the measured urinary 1-OHP levels, the estimated median daily intake doses of pyrene were calculated: 659, 623, 162, and 77.4 ng/kg/day for the women participating in the study living in areas A, B, C, and D, respectively, and finally, the hazard quotient (HQ) was calculated (22 ± 21, 21 ± 20, 5.5 ± 5.5, and 2.6 ± 3.5; for areas A, B, C, and D, respectively), high health risk was noted for the women living in the studied communities. The data shown in this study (exposure levels to PAHs and health risk assessment) made it reasonable to conclude that the exposure levels found have a significant potential for generating adverse effects on human health in the studied scenarios.

Review of PAH contamination in food products and their health hazards

Public concern over the deleterious effects of polycyclic aromatic hydrocarbons (PAHs) has grown rapidly due to recognition of their toxicity, carcinogenicity, and teratogenicity. The aim of this review is to describe the status of PAH pollution among different food types, the route of dietary intake, measures for its reduction, and legislative approaches to control PAH. To this end, a comprehensive review is outlined to evaluate the status of PAH contamination in many important food categories along with dietary recommendations. Our discussion is also extended to describe preventive measures to reduce PAH in food products to help reduce the risks associated with human intake.

Urinary metabolites of polycyclic aromatic hydrocarbons in Saudi Arabian schoolchildren in relation to sources of exposure

Polycyclic aromatic hydrocarbons contain a number of known carcinogenic compounds, and urinary biomarkers have been widely used as a measure of exposure but quantitative relationships with exposure variables have proved elusive. This study aimed to quantify the relationship between exposures to phenanthrene and pyrene from atmospheric and dietary sources with the excretion of 1-hydroxypyrene and hydroxyphenanthrenes in urine as biomarkers of exposure. The study population consisted of 204 male schoolchildren attending three schools in different parts of Jeddah, Saudi Arabia who provided urine samples on each of three consecutive days. Outdoor air measurements of polycyclic aromatic hydrocarbons were made at the schools and the children provided information on diet, exposure to environmental tobacco smoke and incense, and various lifestyle factors through a questionnaire. Mixed models with random effects for subjects nested within site were fitted in order to examine the relationship between exposure variables and urinary PAH metabolites. A unit increase (1 ng m(-3)) in ambient pyrene (particulate plus gaseous phase) was associated with a 3.5% (95% CI: 1.01%, 5.13%) increase in urinary 1-hydroxypyrene concentration. A unit increase in ambient phenanthrene was associated with a 1.01% (95% CI: 0.03%, 2.02%) increase in total hydroxyphenanthrene concentrations. Consumption of chargrilled food increased the 1-hydroxypyrene and hydroxyphenanthrene concentrations by 24% (95% CI: 11%, 37%) and 17% (95% CI: 8%, 26%) respectively. We did not find evidence of association for environmental tobacco smoke exposure or incense burning. It is concluded that both respiratory exposure and consumption of chargrilled food are considerable sources of PAH exposure in this population as reflected by concentrations of urinary biomarkers.