Elevated Oxidative Damage in Kitchen Workers in Chinese Restaurants

The Comet Assay as a Tool in Human Biomonitoring Studies of Environmental and Occupational Exposure to Chemicals-A Systematic Scoping Review

Biomonitoring of human populations exposed to chemical substances that can act as potential mutagens or carcinogens, may enable the detection of damage and early disease prevention. In recent years, the comet assay has become an important tool for assessing DNA damage, both in environmental and occupational exposure contexts. To evidence the role of the comet assay in human biomonitoring, we have analysed original research studies of environmental or occupational exposure that used the comet assay in their assessments, following the PRISMA-ScR method (preferred reporting items for systematic reviews and meta-analyses extension for scoping reviews). Groups of chemicals were designated according to a broad classification, and the results obtained from over 300 original studies (n = 123 on air pollutants, n = 14 on anaesthetics, n = 18 on antineoplastic drugs, n = 57 on heavy metals, n = 59 on pesticides, and n = 49 on solvents) showed overall higher values of DNA strand breaks in the exposed subjects in comparison with the unexposed. In summary, our systematic scoping review strengthens the relevance of the use of the comet assay in assessing DNA damage in human biomonitoring studies.

Non-carcinogenic and cumulative risk assessment of exposure of kitchen workers in restaurants and local residents in the vicinity of polycyclic aromatic hydrocarbons

Polycyclic aromatic hydrocarbons (PAH_s) are often formed when organic substances do not burn completely. This study evaluates the non-carcinogenic and cumulative risks associated with PAH_s levels by testing blood and urine samples in kitchen workers and residents near restaurants in Shiraz, Iran. Metabolites of PAH in the urine samples as well as clinical parameters in the blood samples were measured. The non-carcinogenic and cumulative risk assessments from exposure of the study groups to PAH metabolites were also evaluated. The highest average concentrations of PAH metabolites were related to kitchen workers (2126.7 ng/g creatinine (ng/g cr)). The metabolites of 1-Hydroxypyrene (1-OHP) and 9-Phenanthrene (9-OHPhe) had the highest and lowest mean concentrations, respectively. A direct correlation was observed between the levels of PAH metabolites with malondialdehyde (MDA) and total antioxidation capacity (TAC) levels (p < 0.05). Hazard Index (HI_i) was obtained less than one (HI_i < 1), indicating low-risk negative health impacts on the target groups. Nevertheless, conducting more studies to determine the health status of these people is quite evident.

Household cooking oil type and risk of oral micronucleus frequency in Chinese nonsmokers

Household animal fat has been linked to increased incidence of cancers compared with vegetable fat. However, few epidemiological studies have associated these two cooking oil types with precancerous genotoxic effects, such as occurrence of micronuclei (MN). This study aimed to explore the association between oral MN frequency and household cooking oil type and whether the association can be attributed to polycyclic aromatic hydrocarbons (PAHs). We collected information about individual cooking oil use, measured genotoxic effects by MN tests and urinary PAHs metabolites (OHPAHs) in 245 nonsmokers. The associations between household cooking oil type and MN frequency and OHPAHs were analyzed using generalized linear models (GLMs) and logistic regression models, evaluating odds ratios and coefficient (95% confidence intervals) (ORs, 95% Cls; β, 95% Cls). The odds of animal fat consumers, rather than vegetable fat consumers, was positively associated with higher MN frequency (OR = 1.94, P < 0.05). The associations were discovered in participants only using kitchen ventilation (OR = 2.04, P < 0.05). Animal fat consumers had higher total OHPAHs than vegetable fat consumers (1.58 ± 0.22 mg/mol, Cr vs 1.20 ± 0.12 mg/mol, Cr; P = 0.028). Significant correlations were observed between total OHPAHs quartiles and increased MN frequency (β = 0.38, P-trend = 0.026). After stratifying by household cooking oil type, sensitivity analyses showed that the positive association between total OHPAHs quartiles and increased MN frequency was only observed in animal fat consumers (β = 0.61, P-trend = 0.030). In conclusion, usage of household animal fat was associated with an increased odds of oral MN frequency in Chinese nonsmokers and the odds correlated with increased PAHs exposure. This finding supplemented evidence associating cooking oil type with genotoxic effects and explained its association with PAHs exposure.

Organic pollutant exposure and health effects of cooking emissions on kitchen staff in food services

This study was conducted to determine the exposure and health risk to cooking fumes of a total of 88 volunteer kitchen staff aged between 18 and 65 years working in five different kitchens in Ankara. Gas- and particle-phase polycyclic aromatic hydrocarbons (PAHs), and volatile organic compound (VOCs) concentrations were evaluated in the indoor air of 5 kitchens. Serum malondialdehyde (MDA) and superoxide dismutase (SOD) levels were analyzed to determine the oxidative damage as a result of the exposure to cooking fumes among the cooks and waiters. Significant positive relationships were found between serum MDA levels of the hot kitchen workers and indoor chrysene (Chr), indeno(1,2,3-c,d)pyrene (Ind), and total VOC levels. Although the carcinogenic risks estimated for the exposed population were between the acceptable/tolerable levels, the hazard quotient (HQ) estimated for the exposure to indoor benzene exceeded the safe level. The results of the study revealed that exposure to organic pollutants in indoor air may be a risk factor for the development of oxidative stress, especially in hot kitchen workers. The importance of efficient ventilation in the kitchen has been pointed out to reduce health risks caused by cooking fumes.

Health risk assessment of polycyclic aromatic hydrocarbons in individuals living near restaurants: a cross-sectional study in Shiraz, Iran

Polycyclic aromatic hydrocarbons (PAHs) are persistent toxic substances that have ubiquitous presence in water, air, soil, and sediment environments, posing serious environmental risks. The present study aimed to investigate the concentrations of urinary PAHs and their health effects in individuals living near restaurants via a health risk assessment analysis. This cross-sectional study was performed on 57 people living near restaurants and 30 individuals as the control group. Five urinary metabolites of PAHs were monitored. In order to evaluate the effects of the urinary metabolites of PAHs on Malondialdehyde (MDA) concentration, Total Anti-oxidation Capacity (TAC) in urine samples, and C-Reactive Protein (CRP) in serum samples, regression model was used by considering the effects of the possible confounding factors. Non-carcinogenic health risk was calculated, as well. The median concentration of urinary PAHs was 1196.70 and 627.54 ng/g creatinine in the people living near restaurants and the control group, respectively. Among the metabolites, the lowest and highest mean concentrations were related to 9-OHPhe and 1-OHP, respectively in the two study groups. Moreover, PAHs were significantly associated with MDA level and TAC (p < 0.05). Hazard Quotient (HQ) and Hazard Index (HI) were less than 1. Long-term studies are required to determine the actual health effects by identifying the sources of PAHs emission and to find ways to decrease the production of these compounds.

Exposure to polycyclic aromatic hydrocarbon-induced oxidative stress in individuals living near restaurants: a cross-sectional study in Shiraz, Iran

Polycyclic aromatic hydrocarbons are environmental pollutants caused by the incomplete combustion of organic matter. The aim of this study was to investigate the concentration of urinary PAHs and their health effects in individuals living near restaurants. This cross-sectional study was done on 57 individuals who were living near 36 restaurants, and 30 individuals as the control group. Five urinary metabolites of PAHs (1-OH pyrene, 1-OH naphthalene, 2-OH naphthalene, 2-OH fluorine, and 9-OH phenanthrenen) were monitored. The total anti-oxidation capacity (TAC), malondialdehyde (MDA), C-reactive protein (CRP), and creatinine were also measured. The mean concentration of the sum of urinary PAHs (ΣOH-PAHs) was 1973.7, and 1687.61 ng/g creatinine in people living near restaurants and control group, respectively. Among the metabolites, the highest mean concentration was related to 1-OH Pyrene in the two study groups. In the individuals living near restaurants, the concentration of PAH metabolites was directly related to MDA and TAC (p < 0.05 for both). The present study findings revealed no significant correlation between PAH metabolites and CRP in the two study groups (P > 0.05). People living near restaurants are more exposed to components in cooking fumes, which may adversely affect their health. Further researches are required to elucidate the effect of PAHs exposure on these individuals' health status.

Risk of two common glandular cell-type cancers (breast and colorectal cancers) in Chinese occupational chefs: a nationwide ecological study in Taiwan

OBJECTIVES

Cooking oil fumes (COFs) contain many carcinogens. We investigated the association between COFs and incidence risk of colorectal cancer and female breast in chefs.

METHODS

We identified Chinese food chefs and non-Chinese food chefs from Taiwan's national database of certified chefs in 1984-2007. In total, 379,275 overall and 259,450 females had not been diagnosed as having any cancer before chef certification. We followed these chefs in Taiwan's Cancer Registry Database (1979-2010) and Taiwan's National Death Statistics Database (1985-2011) for newly diagnosed colorectal cancer and female breast cancer.

RESULTS

A total of 4,218,135 and 2,873,515 person-years were included in our analysis of colorectal cancer and female breast cancer incidence, respectively. Compared to non-Chinese food chefs, the Chinese food chefs had an adjusted IRR for colorectal cancer of 1.65 (95% CI  1.17-2.33). The risk of colorectal cancer was even higher among female Chinese food chefs certified for more than 5 years (adjusted incident rate ratio (IRR) = 2.39, 95% CI   1.38-4.12). For female breast cancer, the risk was also significant (adjusted IRR = 1.40, 95% CI 1.10-1.78) and the risks were even higher in female Chinese food chefs certified for more than 5 years (adjusted IRR = 1.74, 95% CI 1.37-2.22).

CONCLUSIONS

This study found that Chinese food chefs had an increased risk of colorectal cancer and female breast cancer, particularly female chefs who had worked for more than 5 years. Future human and animal studies are necessary to re-confirm these findings.

Grill Workers Exposure to Polycyclic Aromatic Hydrocarbons: Levels and Excretion Profiles of the Urinary Biomarkers

Grilling activities release large amounts of hazardous pollutants, but information on restaurant grill workers’ exposure to polycyclic aromatic hydrocarbons (PAHs) is almost inexistent. This study assessed the impact of grilling emissions on total workers’ exposure to PAHs by evaluating the concentrations of six urinary biomarkers of exposure (OHPAHs): naphthalene, acenaphthene, fluorene, phenanthrene, pyrene, and benzo(a)pyrene. Individual levels and excretion profiles of urinary OHPAHs were determined during working and nonworking periods. Urinary OHPAHs were quantified by high-performance liquid-chromatography with fluorescence detection. Levels of total OHPAHs (∑OHPAHs) were significantly increased (about nine times; p ≤ 0.001) during working comparatively with nonworking days. Urinary 1-hydroxynaphthalene + 1-hydroxyacenapthene and 2-hydroxyfluorene presented the highest increments (ca. 23- and 6-fold increase, respectively), followed by 1-hydroxyphenanthrene (ca. 2.3 times) and 1-hydroxypyrene (ca. 1.8 times). Additionally, 1-hydroxypyrene levels were higher than the benchmark, 0.5 µmol/mol creatinine, in 5% of exposed workers. Moreover, 3-hydroxybenzo(a)pyrene, biomarker of exposure to carcinogenic PAHs, was detected in 13% of exposed workers. Individual excretion profiles showed a cumulative increase in ∑OHPAHs during consecutive working days. A principal component analysis model partially discriminated workers’ exposure during working and nonworking periods showing the impact of grilling activities. Urinary OHPAHs were increased in grill workers during working days.

Biomarkers and indoor air quality: A translational research review

Introduction:

Air pollution is linked to mortality and morbidity. Since humans spend nearly all their time indoors, improving indoor air quality (IAQ) is a compelling approach to mitigate air pollutant exposure. To assess interventions, relying on clinical outcomes may require prolonged follow-up, which hinders feasibility. Thus, identifying biomarkers that respond to changes in IAQ may be useful to assess the effectiveness of interventions.

Methods:

We conducted a narrative review by searching several databases to identify studies published over the last decade that measured the response of blood, urine, and/or salivary biomarkers to variations (natural and intervention-induced) of changes in indoor air pollutant exposure.

Results:

Numerous studies reported on associations between IAQ exposures and biomarkers with heterogeneity across study designs and methods. This review summarizes the responses of 113 biomarkers described in 30 articles. The biomarkers which most frequently responded to variations in indoor air pollutant exposures were high sensitivity C-reactive protein (hsCRP), von Willebrand Factor (vWF), 8-hydroxy-2′-deoxyguanosine (8-OHdG), and 1-hydroxypyrene (1-OHP).

Conclusions:

This review will guide the selection of biomarkers for translational studies evaluating the impact of indoor air pollutants on human health.

Micronucleus Frequency in Exfoliated Buccal Cells of Children Living in an Industrialized Area of Apulia (Italy)

Micronuclei (MN) are biomarkers of early biological effect often used for detecting DNA damage in human population exposed to genotoxic agents. The aim of this study was to evaluate the frequency of MN in exfoliated buccal cells of children living in an industrialized (impacted) area compared with that found in children living in a control area without significant anthropogenic impacts. A total of 462 6–8-year-old children (206 in the impacted area, 256 in the control area) attending primary school were enrolled. A questionnaire was administered to the parents of the recruited children to obtain information about personal data, lifestyles, and food habits of their children. Atmospheric particulate fractions were collected near the involved schools to assess the level of environmental exposure of the children. The presence of MN was highlighted in 68.4% of children living in the impacted area with a mean MN frequency of 0.66‰ ± 0.61‰. MN positivity and frequency were significantly lower in the control area (37.1% and 0.27‰ ± 0.43‰, respectively). The frequency of MN was positively associated with quasi-ultrafine particulate matter (PM_0.5), traffic near the home, and consuming barbecued food; while adherence to the Mediterranean diet and practicing sport were negatively associated.

Interventions targeted at oxidatively generated modifications of nucleic acids focused on urine and plasma markers

Oxidative stress is associated with the development and progression of numerous diseases. However, targeting oxidative stress has not been established in the clinical management of any disease. Several methods and markers are available to measure oxidative stress, including direct measurement of free radicals, antioxidants, redox balance, and oxidative modifications of cellular macromolecules. Oxidatively generated nucleic acid modifications have attracted much interest due to the pre-mutagenic oxidative modification of DNA into 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), associated with cancer development. During the last decade, the perception of RNA has changed from that of a 'silent messenger' to an 'active contributor', and, parallelly oxidatively generated RNA modifications measured as 8-oxo-7,8-dihydro-guanosine (8-oxoGuo), has been demonstrated as a prognostic factor for all-caused and cardiovascular related mortality in patients with type 2 diabetes. Several attempts have been made to modify the amount of oxidative nucleic acid modifications. Thus, this review aims to introduce researchers to the measurement of oxidatively generated nucleic acid modifications as well as critically review previous attempts and provide future directions for targeting oxidatively generated nucleic acid modifications.

Micronuclei in Exfoliated Buccal Cells of Children Living in a Cluster Area of Salento (Southern Italy) with a High Incidence of Lung Cancer: The IMP.AIR Study

During the years 2014–2016 the University of Salento performed the “Impact of Air Quality on Health of Residents in the Municipalities of Cutrofiano, Galatina, Sogliano Cavour, Soleto and Sternatia” (IMP.AIR) study, an epidemiological-molecular research project aiming to evaluate early DNA damage in children living in an area of Salento with high incidence of lung cancer among the male population. One hundred and twenty-two children aged 6–8 years attending primary school were enrolled and the frequency of micronucleated cells (MNC) in oral mucosa was evaluated. In addition, a questionnaire was administered to parents to obtain information about personal data, anthropometric characteristics and lifestyles (physical activity, food habits, family context) of the children and perform a multivariate analysis to detect any factors associated with MNC occurrence. Data on airborne pollutants detected in the study area were acquired by the Regional Agency for the Environmental Protection. The presence of MNC was highlighted in about 42% of children with a mean MNC frequency of 0.49‰. The frequency of MNC was associated to obesity, consumption of red or processed meat and having a mother who smokes. Moreover, the prevalence of biomarkers was higher than in another area of Salento not included in the cluster area.

Tracing biomarker of PAH-exposure and susceptibility factor (GSTM-polymorphism) among cancer patients in Pakistan

We studied cancer patients for possible PAH exposure, using urinary concentration of 1-hydroxypyrene (1-OHP) as a biomarker of internal dose of polycyclic aromatic hydrocarbons (PAHs). The subjects included in this study belonged to various socio-demographic backgrounds, and were diagnosed with cancer (i.e. lung, head and neck or digestive tract cancer). In general, we observed high concentration of urinary 1-OHP among digestive tract cancer patients, compared with the controls (CN) (mean 1.06, median 1.03 and mean 0.62, median 0.63 μmol/mol-Cr in digestive tract cancer patients and controls respectively). The concentrations of urinary 1-OHP were higher than the background level of PAHs; therefore, these groups could have been exposed to PAHs. Highest urinary 1-OHP concentration was observed in digestive tract cancer patients (median 1.25 μmol/mol-Cr) with GSTM-1 genotype. The results of PCA were consistent with qualitative and quantitative data analysis. The contribution of urinary 1-OHP eigenvector revealed a relatively high PAH-exposure among cancer patients compared with CN, while diet and age were influential parameters among cancer patients, which could have a strong link in cancer etiology in the selected exposure groups.

Lifestyles and socio-cultural factors among children aged 6-8 years from five Italian towns: the MAPEC_LIFE study cohort

BACKGROUND

Lifestyles profoundly determine the quality of an individual's health and life since his childhood. Many diseases in adulthood are avoidable if health-risk behaviors are identified and improved at an early stage of life. The aim of the present research was to characterize a cohort of children aged 6-8 years selected in order to perform an epidemiological molecular study (the MAPEC_LIFE study), investigate lifestyles of the children that could have effect on their health status, and assess possible association between lifestyles and socio-cultural factors.

METHODS

A questionnaire composed of 148 questions was administered in two different seasons to parents of children attending 18 primary schools in five Italian cities (Torino, Brescia, Pisa, Perugia and Lecce) to obtain information regarding the criteria for exclusion from the study, demographic, anthropometric and health information on the children, as well as some aspects on their lifestyles and parental characteristics. The results were analyzed in order to assess the frequency of specific conditions among the different seasons and cities and the association between lifestyles and socio-economic factors.

RESULTS

The final cohort was composed of 1,164 children (50.9 boys, 95.4% born in Italy). Frequency of some factors appeared different in terms of the survey season (physical activity in the open air, the ways of cooking certain foods) and among the various cities (parents' level of education and rate of employment, sport, traffic near the home, type of heating, exposure to passive smoking, ways of cooking certain foods). Exposure to passive smoking and cooking fumes, obesity, residence in areas with heavy traffic, frequency of outdoor play and consumption of barbecued and fried foods were higher among children living in families with low educational and/or occupational level while children doing sports and consuming toasted bread were more frequent in families with high socio-economic level.

CONCLUSIONS

The socio-economic level seems to affect the lifestyles of children enrolled in the study including those that could cause health effects. Many factors are linked to the geographical area and may depend on environmental, cultural and social aspects of the city of residence.

Predicting disease onset in clinically healthy people

Virtually all human disease is induced by oxidative stress. Oxidative stress, which is caused by toxic environmental exposure, the presence of disease, lifestyle choices, stress, chronic inflammation or combinations of these, is responsible for most disease. Oxidative stress from all sources is additive and it is the total oxidative stress from all sources that induces the onset of most disease. Oxidative stress leads to lipid peroxidation, which in turn produces Malondialdehyde. Serum malondialdehyde level is an additive parameter resulting from all sources of oxidative stress and, therefore, is a reliable indicator of total oxidative stress which can be used to predict the onset of disease in clinically asymptomatic individuals and to suggest the need for treatment that can prevent much human disease.

Biomarkers of PAH exposure and hematologic effects in subjects exposed to combustion emission during residential (and professional) cooking practices in Pakistan

The aim of this study was to evaluate and compare the exposure of household women and professional male workers to combustion emission in the indoor and semi-outdoor environments, respectively, by using biochemical parameters and the biomarkers of exposure to polycyclic aromatic hydrocarbon (PAH). Female (WR n = 60) and male "cooks" (WC n = 60) exposed to the combustion emission of fuel wood and coal in rural/suburban areas of Pakistan were recruited in this study and compared to non-exposed female (CF) and male (CM) groups (n = 32 and 34, respectively). Urinary biomarkers of PAH exposure including 1-hyroxypyrene (1-OHPyr), α-naphthol, and β-naphthol were analyzed together with the biomarkers of effect, including the serum c-reactive proteins (CRP), white blood cells (WBCs), hemoglobin (Hb), red blood cells (RBC), and platelet (PLT) count. In addition, blood superoxide dismutase (SOD) and urinary level of 8-hydroxydeoxyguanosine (8-OHdG) were evaluated to determine the oxidative stress and DNA damage, respectively. A questionnaire was used to document demographic-, health-, and exposure-related information. The results showed that urinary β-naphthol was almost 44% higher in WR subjects than WC (median 7.69 vs. 3.39 μmol/mol-Cr, respectively; p = 0.01) and respective controls (CF). Higher urinary 8-OHdG were observed in WR (71.1 ng/mg-Cr) than WC (56.37 ng/mg-Cr) (p < 0.001), and lower life status and higher degree of headache were observed in WR than WC. In WCs, however, a low Hb and high WBC (8.29 × 10(3) μL(-1), ranging between 6.1 and 10.6 × 10(3) μL(-1)) were observed in comparison with CM. The study shows that WC subjects used larger amount of fuel and were subjected to prolonged exposure. It was concluded that the role of ventilation is fundamental and WR were more exposed to PAHs despite the fact that WC spent more time in cooking (due to occupational requirement) than WR.

PAH exposure and oxidative stress indicators of human cohorts exposed to traffic pollution in Lahore city (Pakistan)

Pollution from road traffic is not only a major source of exposure to polycyclic aromatic hydrocarbons (PAHs) but also a growing problem in the city of Lahore (Pakistan). In this study, we evaluated exposure to traffic-related PAHs, among subjects including traffic police officers (TPs), rickshaw drivers (RKs) shopkeepers working near main roads (SKs) and a control group (CN) for comparative analyses. We monitored the 1-hydroxypyrene (1-OHP) as biomarkers of exposure to PAHs and its probable association with catalase (CAT), glutathione (GSH) glutathione peroxidase (GSHPx) activity as biomarkers of oxidative stress in selected cohorts from the city Lahore. Results showed that median 1-OHP concentration was significantly higher in TPs than CN (med 1.21 vs. 0.51 μmol mol-C(-1) respectively, P=0.046), followed by RKs (0.68 μmol mol-C(-1), P=0.19 vs. CN). Furthermore, GSH, GSHPx, and CAT activities were also higher in exposed subjects than CN, which indicated that they experienced oxidative stress. Similar, but less severe observations were recorded in SKs. Observation of self-reported health status showed that, on the basis of daily time spent in the middle of heavy traffic, TPs and RKs most frequently suffered from adverse head and respiratory symptoms. The study shows that increasing traffic pollution can be associated with important health risk factor not only for the workers in transport industry but also for the public. Finally, the issue of traffic pollution in Lahore city needs to be addressed on priority.

PAH exposure biomarkers are associated with clinico-chemical changes in the brick kiln workers in Pakistan

In this study we investigated the clinico-chemical parameters and the level of exposure of brick kiln workers to polycyclic aromatic hydrocarbons (PAHs) in Punjab (Pakistan). The brick kiln workers and a non-occupationally exposed group were recruited for comparative analysis of urinary biomarkers of PAH exposure (i.e. 1-hydroxypyrene (1-OHPyr), α-naphthol and β-naphthol) and blood level of superoxide dismutase (SOD), as a biomarker of oxidative stress and other hematologic parameters. Questionnaires were used to document information on socio-demographic characteristics of all the subjects. The analysis of urinary biomarkers showed higher median concentrations of 1-OHPyr, and α- and β-naphthols in brick kiln workers (1.53, 3.65 and 1.53 μmol/mol-Cr, respectively) than non-occupationally exposed group (0.62, 0.64 and 0.66 μmol/mol-Cr, respectively). The 1-OHPyr in brick kiln workers was above the occupational exposure level. Among the clinical parameters of brick kiln workers, hemoglobin (Hb) and red blood cells (RBCs) were very low and closely associate with 1-OHPyr and β-naphthol. Additionally, the white blood cells (WBCs) and superoxide dismutase (SOD) were also elevated in brick kiln workers, which suggested inflammatory symptoms and high oxidative stress. The results show that regardless of possibly being affected by the poor nutrition, the anemic state and hematological changes observed in brick kiln workers may be associated with their exposure to smoke present in the environment of brick kilns.

8-hydroxydeoxyguanosine as a useful marker for determining the severity of trichloroethylene exposure

The aim of this study was to determine 8-hydroxydeoxyguanosine (8-OH-dG) levels in trichloroethylene (TCE)-exposed workers. Oxidative stress biomarkers and biochemical parameters were monitored among 26 TCE-exposed workers and 78 age-matched control subjects. Levels of urinary 8-OH-dG were analyzed by liquid chromatography tandem mass spectrometry. Urinary 8-OH-dG levels were significantly higher for TCE-exposed group (p < .001). Spearman's correlation test revealed positive correlations between urinary trichloroacetic acid levels and age, urinary 8-OH-dG, urinary total oxidant status, and urinary total antioxidant status (p = .042, p < .001, p < .001, and p < .001, respectively). 8-OH-dG may be a useful marker to determine the extent of TCE exposure.

Epigenetic markers of exposure to polycyclic aromatic hydrocarbons in Mexican brickmakers: a pilot study

A pilot cross-sectional study was carried out in a group of 39 male brick manufacturers in San Luis Potosi, Mexico to identify epigenetic biomarkers of exposure to polycyclic aromatic hydrocarbons (PAHs). A questionnaire was used to compile the smoking and drinking habits, clinical history, working time, and socioeconomic characteristics of the participants. 1-Hydroxypyrene (1-OHP) levels were measured from urine samples using high-performance liquid chromatography, and genomic DNA was isolated from blood samples for methylation analysis using pyrosequencing. The mean 1-OHP level was 0.18 μg g(-1) creatinine (range 0.023-1.11), which was below the expected occupational exposure level. After adjusting for potential confounders, the 1-OHP urine concentration was negatively associated with DNA methylation of the interleukin 12 (β=-1.57; 95% CI: -2.9 to -0.23; p=0.02) and p53 gene promoters (β=-2.7; 95% CI: -5.46-0.06; p=0.055). Suggestive negative associations were also found for the TNF-α gene (β=-3.9; 95% CI:-8.28-0.48; p=0.08) and Alu sequences (β=-0.55; 95% CI:-1.25-0.16; p=0.12). Although the individual exposures to PAHs as estimated by urinary 1-OHP concentrations were low, changes in specific and global DNA methylation were observed.