Longitudinal assessment of oxidative stress markers and their relationship with exposure to PM2.5 and its bound metals in healthy participants

OBJECTIVE

Exposure to ambient PM2.5 and its bound metals poses a risk to health and disease, via, in part, oxidative stress response. A variety of oxidative stress markers have been used as markers of response, but their relevance to environmental exposure remains to be established. We evaluated, longitudinally, a battery of oxidative stress markers and their relationship with the exposure of PM2.5 and its bound metals in a panel of healthy participants.

MATERIAL AND METHODS

Levels of residence- and personal-based ambient air PM2.5 and its bound metals, as well as of lung function parameters, were assessed in a total of 58 questionnaire-administered healthy never smoker participants (male, 39.7%). Levels of urinary oxidative stress markers, including Nε-(hexanoyl)-lysine (HEL; an early lipid peroxidation product), 4-hydroxynonenal (4-HNE), N7-methylguanine (N7-meG), and 8-hydroxy-2-deoxyguanosine (8-OHdG), plasma antioxidants [superoxide dismutase (SOD) and glutathione peroxidase (GPx), and urinary metals were measured by ELISA, LC-MS, and ICP-MS, respectively. The results of three repeated measurements at two-month intervals were analyzed using the Generalized Estimating Equation (GEE).

RESULTS

After adjusting for confounders, residence- and personal-based PM2.5 levels were positively associated with HEL (β = 0.22 and 0.18) and N7-meG (β = 0.39 and 0.13). Significant correlations were observed between personal air PM2.5-Pb and urinary Pb with HEL (β = 0.08 and 0.26). While FVC, FEV1, FEV1/FVC, MMF, and PEFR predicted% were normal, a negative interaction (pollutant*time, P < 0.05) was noted for PM2.5-V, Mn, Co, Ni, Zn, As, and Pb. Additionally, a negative interaction was found for N7-meG (β = -21.35, -18.77, -23.86) and SOD (β = -26.56, -26.18, -16.48) with FEV1, FVC, and PEFR predicted%, respectively.

CONCLUSION

These findings emphasize potential links between environmental exposure, internal dose, and health effects, thereby offering valuable markers for future research on metal exposure, oxidative stress, and health outcomes.

The roles of lumbar load thresholds in cumulative lifting exposure to predict disk protrusion in an Asian population

Background

The purpose of this study was to determine whether a specific threshold per lifting movement, the accumulation above which best predicts lumbar disk protrusion, exists or the total lifting load should be considered.

Methods

This was a retrospective study. Subjects with various lifting exposures were recruited. Disk protrusion was assessed by magnetic resonance imaging. The cumulative lifting load was defined as the sum of the time-weighed lumbar load for each job and was calculated using a biomechanical software system. The effectiveness of accumulation above different thresholds in predicting disk protrusion were compared using four statistical methods.

Results

A total of 252 men and 301 women were included in the final analysis. For the men, 3000 Newtons for each lifting task was the optimal threshold for predicting L4-S1 disk protrusion, whereas for the women, 2800 Newtons was optimal.

Conclusions

Our findings suggested that for cumulative lifting exposure, including the total lifting load without defining a minimal exposure limit might not be the optimal method for predicting disk protrusion. The NIOSH 3400 Newton recommended limits do not appear to be the optimal thresholds for preventing disk protrusion. Different lifting thresholds might be needed for men and women in the workplace for their safety.

Longitudinal follow-up of health effects among workers handling engineered nanomaterials: a panel study

BACKGROUND

Although no human illness to date is confirmed to be attributed to engineered nanoparticles, occupational epidemiological studies are needed to verify the health effects of nanoparticles. This study used a repeated measures design to explore the potential adverse health effects of workers handling nanomaterials.

METHODS

Study population was 206 nanomaterial-handling workers and 108 unexposed controls, who were recruited from 14 nanotechnology plants. They were followed up no less than two times in four years. A questionnaire was used to collect potential confounders and detailed work conditions. Control banding was adopted to categorize risk level for each participant as a surrogate marker of exposure. Health hazard markers include cardiopulmonary dysfunction markers, inflammation and oxidative damage markers, antioxidant enzymes activity, and genotoxicity markers. The Generalized Estimating Equation model was applied to analyze repeated measurements.

RESULTS

In comparison to the controls, a significant dose-dependent increase on risk levels for the change of superoxide dismutase (p<0.01) and a significant increase of glutathione peroxidase change in risk level 1 was found for nanomaterial-handling workers. However, the change of cardiovascular dysfunction, lung damages, inflammation, oxidative damages, neurobehavioral and genotoxic markers were not found to be significantly associated with nanomaterials handling in this panel study.

CONCLUSIONS

This repeated measurement study suggests that there was no evidence of potential adverse health effects under the existing workplace exposure levels among nanomaterials handling workers, except for the increase of antioxidant enzymes.

Effects of nanoparticles exposure and PON1 genotype on heart rate variability

OBJECTIVES

This study was to assess the association between different NPs exposure and PON1 genotype on Heart Rate Variability (HRV) parameters among workers.

METHODS

This study included 235 non-CVD subjects handled to nanomaterials (NM) and 185 non-exposed controls without CVD from 14 NM plants. All participants completed short-term HRV measurements, and were collected blood specimens to measure PON1 activities and the genotype of the PON1 Q192R polymorphism.

RESULTS

In a multivariate regression model, this study observed a positive relationship between nano-Ag exposure and HRV time-domain (RMSSD) and frequency-domain (HF). After adjusting for confounders, the results showed positive associations between RR homozygosity, PON1 paraoxonase/arylesterase activities with HRV, and was particularly noteworthy in RMSSD and HF.

CONCLUSIONS

This study shows a significant increment of RMSSD and HF among workers who handled Nano-Ag materials. These results imply that Nano-Ag and PON1 Q192R genotype can trigger ANS reflexes and alter cardiac frequency and function.

Measurement of urinary arsenic profiles and DNA hypomethylation in a case-control study of urothelial carcinoma

Environmental exposure to arsenic may be involved in the disturbance of DNA hypomethylation. The aim of this study is the first to explore the effect of interactions of urinary total arsenic levels, arsenic methylation capacity, 8-hydroxy-2'-deoxyguanosine (8-OHdG), plasma folate, and global 5-methyl-2'-deoxycytidine (5-MedC) levels on the risk of urothelial carcinoma (UC). A hospital-based case-control study was constructed. The research involved the histological recruitment and pathological verification of 178 UC patients and 356 age-/sex-matched controls without prior history of cancer. Arsenic species were determined by high-performance liquid chromatography (HPLC)-hydride generation and atomic absorption. 5-MedC levels were detected by HPLC and triple-quadrupole mass spectrometry (MS). 8-OHdG was processed by an online solid-phase extraction LC-MS/MS. Plasma folate levels were measured using the chemiluminescent technology. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by multiple logistic regression analysis. Results indicate that the high levels of total urinary arsenic, inorganic arsenic percentage, and 8-OHdG and the low levels of DMA % and plasma folate were independent factors of UC. In addition, global 5-MedC levels in the first quartile versus fifth quartile significantly increased the twofold OR of UC after potential factors were adjusted (95% CI:1.10-4.03). The interaction of 5-MedC level and high total arsenic level, insufficient arsenic capacity, high 8-OHdG, and low folate levels was insignificant. Results of stepwise logistic regression analysis indicate that high total urinary arsenic levels (Q3 versus Q1), low plasma folate level, and low global 5-MedC (Q4 versus Q5) significantly increased the ORs of UC. The above results suggest that high total arsenic, low plasma folate, and 5-MedC levels affect the ORs of UC independently.

O5D.4 Exposure profiles of workers in indium-tin oxide powder manufacturing, target manufacturing and recycling factories in taiwan

We aimed to investigate indium exposure profiles and the relationship between ambient exposure and internal dose of indium among workers with different job characteristics in order to improve the work environment and protect workers from overexposure.

We recruited 329 workers from indium-tin oxide (ITO) powder and target manufacturing and recycling factories. The workers were categorized into six groups, as powder, ITO target, bonding, processing, recycling process and administration department as reference group. Field and personal air sampling were performed to monitor indium concentrations of work environments and breathing zones of workers. Cumulative exposure were evaluated by respirable dust concentrations in personal sampling, exposure duration and work duration. Plasma indium (P-In), urine indium (U-In) and U-In adjusted for creatinine (U-In/creatinine) were used as internal dose.

One-fourth of air indium concentrations of ITO manufacturing and recycling factories were exceeded permissible exposure limit (PEL) in Taiwan. Thirty-six percent of workers in this study exposed to unacceptable airborne concentration of indium. Over one-fifth of workers had P-In higher than Japanese biological exposure index (BEI) of 3 µg/L. After adjusting for potential confounders, significant positive were found between indium cumulative exposure and P-In (β=0.56, p<0.001), U-In (β=0.38, p<0.001), and U-In/creatinine (β=0.34, p<0.001) in bonding process. A significant positive were found between indium cumulative exposure and P-In (β=0.53, p=0.003), U-In (β=0.39, p=0.047) and U-In/creatinine (β=0.34, p=0.01) in processing process.

We suggest that U-In was an useful biomarker to assess indium exposure of indium manufacturing workers. The distribution and elimination of indium differed by its chemical form, which lead to characterization of the chemical form of indium is important for biomonitoring. Notably, although workers were exposed to indium below PEL, P-In still exceeded Japanese BEI. An appropriate exposure index need to be specified.

Identification of osteopontin as a biomarker of human exposure to fine particulate matter

Ambient particulate matter (PM) exposure is associated with pulmonary and cardiovascular diseases; however, there is scant research linking data on animal and human cells. The objective of this study was to investigate these associations. Vascular remodeling plays a crucial role in both pulmonary and cardiovascular diseases. Therefore, we conducted a transcriptomic analysis using vascular smooth muscle cells (VSMCs) to identify potential regulators or markers of PM exposure. We demonstrated that fine and coarse PM increased VSMC proliferation in mice. We conducted a genome-wide cDNA microarray analysis, followed by a pathway analysis of VSMCs treated with coarse PM for durations of 24, 48, and 72 h. Sixteen genes were discovered to be time-dependently upregulated and involved in VSMC proliferation. Osteopontin (OPN) is indicated as one of the regulators of these upregulated genes. Both fine and coarse PM from industrial and urban areas significantly increased OPN expression in VSMCs and macrophages. Moreover, oropharyngeal instillation of fine and coarse PM for 8 weeks increased the VSMCs in the pulmonary arteries of mice. OPN level was consistently increased in the lung tissues, bronchoalveolar lavage fluid, and serum of mice. Moreover, we analyzed the plasma OPN levels of 72 healthy participants recruited from the studied metropolitan area. Each participant wore a personal PM_2.5 sampler to assess their PM_2.5 exposure over a 24 h period. Our results indicate that personal exposure to fine PM is positively correlated with plasma OPN level in young adults. The data obtained in this study suggest that exposure to fine and coarse PM may cause pulmonary vascular lesions in humans and that OPN level may be a biomarker of PM exposure in humans.

Levels and temporal variations of urinary lead, cadmium, cobalt, and copper exposure in the general population of Taiwan

Toxic metal contamination in food products and the environment is a public health concern. Therefore, understanding human exposure to cadmium (Cd), lead (Pb), cobalt (Co), and copper (Cu) levels in the general population of Taiwan is necessary and urgent. We aimed to establish the human biomonitoring data of urine toxic metals, exposure profile changes, and factors associated with metal levels in the general population of Taiwan. We randomly selected 1601 participants older than 7 years of age (36.9 ± 18.7 years (7-84 years)) from the Nutrition and Health Survey in Taiwan (NAHSIT) conducted during 1993-1996 (93-96) and 2005-2008 (05-08) periods and measured the levels of four metals in the participants' urine samples using inductively coupled plasma-mass spectrometry. The median (range) levels of urinary Cd, Pb, Co, and Cu in participants from the NAHSIT 93-96 (N = 821)/05-08 (N = 780) were 0.60 (ND-13.90)/0.72 (ND-7.44), 2.28 (ND-63.60)/1.09 (0.04-48.88), 0.91 (0.08-17.30)/1.05 (0.05-22.43), and 16.87 (2.62-158.28)/13.66 (1.67-189.70) μg/L, respectively. We found that the urinary median levels of Pb and Cu in our participants were significantly lower in the NAHSIT 05-08 (Pb 1.09 μg/L, Cu 13.66 μg/L) than in the NAHSIT 93-96 (Pb 2.28 μg/L, Cu 16.87 μg/L; P < 0.01), whereas those of Cd and Co were significantly higher in the NAHSIT 05-08 (Cd 0.72 μg/L, Co 1.05 μg/L; P < 0.01). Youths had higher exposure levels of Pb, Co, and Cu than adults. Participants with alcohol consumption, betel quid chewing, or cigarette smoking had significantly higher median levels of urinary Pb or Cu (P < 0.01) than those without. Principal components and cluster analysis revealed that sex had different exposure profiles of metals. We concluded that levels of urinary Cd, Pb, Co, and Cu exposure in the general Taiwanese varied by age, sex, and lifestyles.

Clustering of malignant pleural mesothelioma in asbestos factories: a subgroup analysis in a 29-year follow-up study to identify high-risk industries in Taiwan

OBJECTIVE

Exposure to asbestos is the major cause for malignant pleural mesothelioma (MPM), but the causal link of individual cases is difficult to establish for lack of exposure information and long disease latency.

METHODS

We established a retrospective cohort of workers employed in asbestos industries during the period of 1950-1989 and the occurrence of MPM during the period of 1980-2009 was examined with the Taiwan Cancer Registry. Estimated rate ratios (eRRs) were computed for each factory where any case of MPM was diagnosed by assuming Poisson distribution with a minimal latency of 20 years.

RESULTS

A total of 18 MPM (17 males, 1 female) in eight factories were found. The incidence rate of MPM for the eight factories was 18.0 per million, ranging from 6.2 per million (military factory) to 268.2 per million (asbestos cement). We observed significantly increased risks for MPM in asbestos cement, thermal insulation and shipbuilding industries, with eRR (genders combined) of 113.6, 87.5 and 15.8, respectively. The sensitivity analyses considering latency showed similar findings in latency ≥30 years, and the shipbuilding industry presented a significant eRR given a latency ≥40 years. The gender-specific eRR showed similar results in men, but high eRR of 729.6 was observed in an asbestos cement factory where a female MPM was diagnosed.

CONCLUSIONS

This nationwide study in Taiwan comprehensively shows that different asbestos manufacturing processes, including asbestos cement, thermal insulation and shipbuilding industries, were at significantly increased risks for MPM. We recommend to establish a medical screening programme for workers previously exposed to asbestos to identify MPM and other asbestos-related diseases at an earlier stage.

Feasibility of using urinary N7-(2-carbamoyl-2-hydroxyethyl) Guanine as a biomarker for acrylamide exposed workers

Acrylamide (AA), a probable human carcinogen, is a widely-used industrial chemical but is also present in tobacco smoke and carbohydrate-rich foods processed at high temperatures. AA is metabolized to glycidamide (GA) to cause the formation of DNA adducts. N7-(2-carbamoyl-2-hydroxyethyl) guanine (N7-GAG), the most abundant DNA adduct induced by GA, was recently detected in urine of smokers and non-smokers. In this study, we assessed the variability of AA exposure and biomarkers of AA exposure in urine samples repeatedly collected from AA-exposed workers and explored the half-life of N7-GAG. A total of 8 AA-exposed workers and 36 non-exposed workers were recruited. Pre-shift and post-shift urine samples were collected from the exposed group in parallel with personal sampling for eight consecutive days and from the control group on day 1 of the study. Urinary N7-GAG and the mercapturic acids of AA and GA, namely N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-(R,S)-acetyl-S-(1-carbamoyl-2-hydroxyethyl)-L-cysteine (GAMA) were analyzed using on-line solid phase extraction-liquid chromatography-electrospray ionization/tandem mass spectrometry methods. We found that N7-GAG levels in urine were significantly higher in exposed workers than in controls and that N7-GAG level correlated positively with AAMA and GAMA levels. Results from this study showed that AAMA and GAMA possibly remain the more preferred biomarkers of AA exposure and that N7-GAG levels could be elevated by occupational exposures to AA and serve as a biomarker of AA-induced genotoxicity for epidemiological studies.

Risk of Alzheimer's disease with metal concentrations in whole blood and urine: A case-control study using propensity score matching

Environmental exposure to heavy metals is suspected to result in neuropathology damage and cognitive impairment. We aimed to explore the association of Alzheimer's disease (AD) risk with the internal dose of heavy metals by constructing a hospital-based case-control study and using propensity-score-matching methods. We investigated 170 patients with AD and 264 controls from the Department of Neurology and Family Medicine, China Medical University Hospital in Taiwan. All patients with AD received clinical neuropsychological examination and cognitive-function assessments, including the mini-mental status examination and clinical dementia rating scale. We also constructed a propensity-score-matched population of 82 patients with AD and 82 controls by matching age, gender, education, and AD-related comorbidity. Blood levels with cadmium, lead, mercury, selenium, and urinary arsenic profile were measured. Logistic regression models and 95% confidence intervals (CIs) were applied to estimate AD risk. After stratification by respective quartile cutoffs of heavy metals, the AD risk of study participants with high urinary inorganic arsenic (InAs%) or low dimethylarsinic acid (DMA%) significantly increased (p < 0.05), as similarly found in the propensity-score-matched population. In addition, people with a low median level of selenium and high median level of InAs%, or/and a low median level of DMA% had approximately two- to threefold significant AD risk. Urinary arsenic profiles may be associated with increased AD risk. Repeat measurements of heavy metals with large sample size and the surveying of potential exposure sources are recommended in future studies.

Usefulness of overnight pulse oximeter as the sleep assessment tool to assess the 6-year risk of road traffic collision: evidence from the Taiwan Bus Driver Cohort Study

Background

In order to support health service organizations in arranging a system for prevention of road traffic collisions (RTC), it is important to study the usefulness of sleep assessment tools. A cohort study was used to evaluate the effectiveness of subjective and objective sleep assessment tools to assess for the 6-year risk of both first RTC event only and recurrent RTC events.

Methods

The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1650 professional drivers from a large bus company in Taiwan in 2005. The subjects were interviewed in person, completed the sleep assessment questionnaires and had an overnight pulse oximeter survey. Moreover, this cohort of drivers was linked to the National Traffic Accident Database (NTAD) and researchers found 139 new RTC events from 2005 to 2010. Primary outcomes were traffic collisions from NTAD, nocturnal oxygen desaturation index (ODI) from pulse oximeter, Pittsburg sleeping quality score, Epworth daytime sleepiness score, Snore Outcomes Survey score and working patterns from questionnaires. A Cox proportional hazards model and an extended Cox regression model for repeated events were performed to estimate the hazard ratio for RTC.

Results

The RTC drivers had increased ODI4 levels (5.77 ± 4.72 vs 4.99 ± 6.68 events/h; P  = 0.008) and ODI3 levels (8.68 ± 6.79 vs 7.42 ± 7.94 events/h; P  = 0.007) in comparison with non-RTC drivers. These results were consistent regardless of whether ODI was evaluated as a continuous or a categorical variable. ODI4 and ODI3 levels increased the 6-year RTC risks among professional drivers even after adjusting for age, education, history of cardiovascular disease, caffeine intake, sleeping pills used, bus driving experience and shift modes. Moreover, there was an increased trend for ODI between the stratification of the number of RTCs in comparison with the non-RTC group. In the extended Cox regression models for repeated RTC events with the Anderson and Gill intensity model and Prentice-Williams-Petersen model, measurement of ODI increased hazards of the subsequent RTC events.

Conclusion

This study showed that an increase in the 6-year risk of RTC was associated with objective measurement of ODI for a sign of sleep-disordered breathing (SDB), but was not associated with self-reported sleeping quality or daytime sleepiness. Therefore, the overnight pulse oximeter is an effective sleep assessment tool for assessing the risk of RTC. Further research should be conducted regarding measures to prevent against SDB among professional drivers.

Exposure to fine particulate matter causes oxidative and methylated DNA damage in young adults: A longitudinal study

An increased understanding is needed of the physiological effects and plausible biological mechanisms that link PM_2.5 (particulate matter with an aerodynamic diameter below 2.5μm) exposure to mortality and morbidities such as atherosclerosis and respiratory disease. PM_2.5 causes carcinogenic health effects. Biomonitoring in humans has suggested that 8-oxo-7, 8-dihydro-2-deoxyguanosine (8-oxodG) and N7-methylguanine (N7-MeG) are correlated with oxidative and methylated DNA damage. Thus, it is meaningful to explore the mechanisms of mutagenesis and carcinogenesis associated with oxidative and methylated DNA damage by simultaneously measuring these two markers. We recruited 72 participants from 2 areas (residential and commercial as well as residential and industrial) in the greater Taipei metropolitan area at baseline. Personal samplers were used to collect 24-hour PM_2.5-integrated samples. All participants completed an interview, and blood and urine samples were collected the next morning. All collection procedures were repeated twice after a two-month follow-up period. Urinary 8-oxodG and N7-MeG were assayed as biomarkers of oxidative and methylated DNA damage, respectively. Plasma superoxide dismutase (SOD) and glutathione peroxidase-1 (GPX-1) were measured as biomarkers of antioxidants. Urinary 1-hydroxypyrene (1-OHP) was used as a biomarker of exposure to polycyclic aromatic hydrocarbons (PAHs). The mean PM_2.5 level was 37.3μg/m³ at baseline. PM_2.5 concentrations were higher during winter than during spring and summer. After adjusting for confounds through a generalized estimating equation (GEE) analysis, N7-MeG was significantly increased by 8.1% (β=0.034, 95% CIs=0.001-0.068) per 10μg/m³ increment in PM_2.5. 8-oxodG levels were positively correlated with N7-MeG according to both cross-sectional and longitudinal analyses, and 1-OHP was significantly associated with increasing 8-oxodG and N7-MeG concentrations. Exposure to PM_2.5 increases methylated DNA damage. The mean level of urinary N7-MeG was 1000-fold higher than that of 8-oxodG.

Global DNA methylation and oxidative stress biomarkers in workers exposed to metal oxide nanoparticles

This is the first study to assess global methylation, oxidative DNA damage, and lipid peroxidation in workers with occupational exposure to metal oxide nanomaterials (NMs). Urinary and white blood cell (WBC) 8-hydroxydeoxyguanosine (8-OHdG), and exhaled breath condensate (EBC) 8-isoprostane were measured as oxidative stress biomarkers. WBC global methylation was measured as an epigenetic alteration. Exposure to TiO₂, SiO_2, and indium tin oxide (ITO) resulted in significantly higher oxidative biomarkers such as urinary 8-OHdG and EBC 8-isoprostane. However, significantly higher WBC 8-OHdG and lower global methylation were only observed in ITO handling workers. Significant positive correlations were noted between WBC and urinary 8-OHdG (Spearman correlation r=0.256, p=0.003). Furthermore, a significant negative correlation was found between WBC 8-OHdG and global methylation (r=-0.272, p=0.002). These results suggest that exposure to metal oxide NMs may lead to global methylation, DNA oxidative damage, and lipid peroxidation.

Relationships among DNA hypomethylation, Cd, and Pb exposure and risk of cigarette smoking-related urothelial carcinoma

Cigarette smoking and environmental exposure to heavy metals are important global health issues, especially for urothelial carcinoma (UC). However, the effects of cadmium and lead exposure, as well as the levels of DNA hypomethylation, on UC risk are limited. We evaluated the possible exposure sources of Cd and Pb and the relationship among DNA hypomethylation, urinary Cd and Pb levels, and UC risk. We recruited 209 patients with UC and 417 control patients for a hospital-based case-control study between June 2011 and August 2014. We collected environmental exposure-related information with questionnaires. Blood and urine samples were analyzed to measure the Cd and Pb exposure and 5-methyl-2'-deoxycytidine levels as a proxy for DNA methylation. Multivariate logistic regression and 95% confidence intervals were applied to estimate the risk for UC. Study participants with high Cd and Pb exposure in blood or urine had significantly increased risk of UC, especially among the smokers. After adjusting for age and gender, the possible connections of individual cumulative cigarette smoking or herb medicine exposure with the increased levels of Cd and Pb were observed in the controls. Participants with 8.66%-12.39% of DNA hypomethylation had significantly increased risk of UC compared with those with ≥12.39% of DNA hypomethylation. Environmental factors including cigarette smoking and herb medicine may contribute to the internal dose of heavy metals levels. Repeat measurements of heavy metals with different study design, detailed dietary information, and types of herb medicine should be recommended for exploring UC carcinogenesis in future studies.

Effect of CYP3A4 genetic polymorphisms on the genotoxicity of 4,4'-methylene-bis(2-chloroaniline)-exposed workers

OBJECTIVES

We investigated the relationship between 4,4'-methylene-bis(2-chloroaniline) (MBOCA) exposure and micronucleus (MN) frequency, and how this association was affected by genetic polymorphism of the cytochrome P450 enzyme (CYP3A4).

METHODS

We divided the study population into an exposed group (n=44 with total urine MBOCA ≥20 μg/g creatinine) and a control group (n=47 with total urine MBOCA <20 μg/g creatinine). Lymphocyte MN frequency (MNF) and micronucleated cell (MNC) frequency were measured by the cytokinesis-block MN assay method. MNF reported as the number of micronuclei in binucleated cells per 1000 cells, and MNC reported as the number of binucleated cells with the presence of MN per 1000 cells. CYP3A4 alleles were measured by PCR-based restriction fragment length polymorphism (PCR-RFLP).

RESULTS

The mean MNF (6.11 vs 4.46 MN/1000 cells, p<0.001) and MNC (5.75 vs 4.15 MN/1000 cells, p<0.001) in the exposed workers was significantly higher than that in the controls. The CYP3A4 polymorphism A/A+A/G influenced the difference in the mean MNF (5.97 vs 4.38 MN/1000 cells, p<0.001) and MNC (5.60 vs 4.15 MN/1000 cells, p<0.001) between the MBOCA-exposed and control groups. After adjusting risk factors, the MNF level in the MBOCA-exposed workers was 0.520 MN cells/1000 cells (p<0.001) higher than the control group among the CYP3A4 A/A+A/G genotype. Similarly, the MNC level in the MBOCA-exposed workers was 0.593 MN/1000 cells (p<0.001) higher than the control group among the CYP3A4 A/A+A/G genotype. However, the difference in adjusted MNF and MNC between the exposed and control groups was not significant for the CYP3A4 polymorphism with the G/G genotype.

CONCLUSIONS

We recommend that lymphocytes MNF and MNC are good indicators to evaluate MBOCA genotoxicity. Individuals with the CYP3A4 polymorphism A/A and A/G genotypes appear to be more susceptible to MBOCA genotoxicity.

Utility of overnight pulse oximeter as a screening tool for sleep apnea to assess the 8-year risk of cardiovascular disease: Data from a large-scale bus driver cohort study

BACKGROUND

Professional drivers' work under conditions predisposes them for development of sleep-disordered breathing (SDB) and cardiovascular disease (CVD). However, the effect of SDB on CVD risk among professional drivers has never been investigated. A cohort study was used to evaluate the effectiveness of overnight pulse oximeter as a sleep apnea screening tool to assess the 8-year risk of CVD events.

METHODS

The Taiwan Bus Driver Cohort Study (TBDCS) recruited 1014 professional drivers in Taiwan since 2005. The subjects completed questionnaire interview and overnight pulse oximeter survey. This cohort was linked to the National Health Insurance Research Dataset (NHIRD). Researchers found 192 CVD cases from 2005 to 2012. Cox proportional hazards model was performed to estimate the hazard ratio for CVD. The statistical analysis was performed using SAS software in 2015.

RESULTS

ODI4 and ODI3 levels increased the 8-year CVD risk, even adjusting for CVD risk factors (HR: 1.36, 95% CI: 1.05 to 1.78; p=0.022, and HR: 1.40, 95% CI: 1.03 to 1.90; p=0.033). ODI4 and ODI3 thresholds of 6.5 and 10events/h revealed differences of CVD risks (HR: 1.72, 95% CI: 1.00 to 2.95; p=0.048, and HR: 1.76, 95% CI: 1.03 to 3.03; p=0.041). Moreover, the ODI levels had an increased risk for hypertensive disease (not including essential hypertension).

CONCLUSIONS

This study concludes that ODI for a sign of SDB is an independent predictor of elevated risk of CVD. Further research should be conducted regarding measures to prevent against SDB in order to reduce CVD risk in professional drivers.

The relationship between plasma and urinary 8-hydroxy-2-deoxyguanosine biomarkers measured by liquid chromatography tandem mass spectrometry

Although 8-hydroxy-2-deoxyguanosine (8-OHdG) is a widely used promising biomarker of DNA damage, there are concerns about which tissues or body fluids should be sampled. The objective of this study is to evaluate the correlation of DNA oxidative damage biomarkers, 8-OHdG, between blood and urine and risk factors associated with 8OHdG. The study population was recruited from a baseline survey of a worksite lifestyle study including 92 office workers aged 23 to 60 years. A self-administered questionnaire was used to collect information on personal characteristics. The plasma and urinary 8-OHdG was measured by liquid chromatography tandem mass spectrometry (LC-MS/MS). In linear regression, a positive relation was found (p < 0.01) between the log-transformed plasma and urinary 8-OHdG levels adjusted for gender, age, BMI, and smoking status. Our findings showed that age, gender and smoking were significantly associated with plasma 8-OHdG, but not with urinary 8-OHdG. Our results suggest that there is a positive relation between the biomarkers of plasma (steady state DNA damage) and urinary 8-OHdG (total DNA damage). However, the plasma 8-OHdG is more sensitive than urinary 8-OHdG to detect increased oxidative damages induced by risk factors.

Association between urinary lead and bone health in a general population from Taiwan

Lead accumulates in adult bones for many decades; previous studies have shown lead's detrimental effects on osteoblast and osteoclast activity in association with bone remodeling. Osteoporosis is a disease of the bones resulting in low bone mass that induces fragile bones and hence susceptibility of fracture. We estimated the association between urinary lead (U-Pb) levels and bone health in adults participating in the third Nutrition and Health Survey in Taiwan (NAHSIT) from 2005 to 2008. A total of 398 participants were divided into normal (T-score>-1), osteopenic (T-score between -1 and -2.5), or osteoporotic (T-score<-2.5) groups according to the results of bone mineral density (BMD) measurements. Heavy metals were measured in urine specimens using inductively coupled plasma-mass spectrometry. In the multivariable logistic regression analysis, age (OR=1.08; 95% CI=1.05-1.10), former smokers (OR=2.95; 95% CI=1.22-7.11) and higher U-Pb levels than upper tertile (OR=2.30; 95% CI=1.19-4.48) were associated with osteopenia/osteoporosis. Furthermore, age (OR=1.06; 95% CI=1.02-1.10) and higher U-Pb levels (OR=2.81; 95% CI=1.13-6.97) were significantly associated with osteopenia and osteoporosis in women. These results suggest that adults, particularly in women, with higher U-Pb levels may have increased odds of osteopenia and osteoporosis.

Association between levels of urinary heavy metals and increased risk of urothelial carcinoma

OBJECTIVES

To evaluate possible sources of exposure to heavy metals in the general population, and to determine the association between urinary heavy metals and urothelial carcinoma risk.

METHODS

We recruited 205 patients with urothelial carcinoma and 406 control participants for a case-control study between June 2011 and December 2013. The control participants were frequency-matched with cases according to sex and age. We measured the urinary levels of arsenic, cadmium, chromium, nickel and lead by using inductively coupled plasma mass spectrometry. We collected environmental exposure-related information through questionnaires. Multivariate logistic regression and 95% confidence intervals were applied to estimate the urothelial carcinoma risk and potential effects of urothelial carcinoma-related risk factors on the levels of urinary heavy metals.

RESULTS

Patients with urothelial carcinoma showed higher urinary levels of arsenic, cadmium, chromium, nickel and lead than the controls. After considering other potential risk factors, a significantly increased risk for urothelial carcinoma was observed in patients with increased urinary levels of cadmium, chromium, nickel and lead. Smokers showed a high urinary cadmium level. In addition to cadmium, a high urinary lead level was associated with cumulative cigarette smoking and herbal medicine use.

CONCLUSION

Environmental factors might contribute to higher urinary levels of heavy metals and ultimately result in urothelial carcinoma carcinogenesis. These findings can promote proper environmental surveillance of exposure to heavy metals in the general population.

Assessing the first wave of epidemiological studies of nanomaterial workers

The results of early animal studies of engineered nanomaterials (ENMs) and air pollution epidemiology suggest that it is important to assess the health of ENM workers. Initial epidemiological studies of workers' exposure to ENMs (<100 nm) are reviewed and characterized for their study designs, findings, and limitations. Of the 15 studies, 11 were cross-sectional, 4 were longitudinal (1 was both cross-sectional and longitudinal in design), and 1 was a descriptive pilot study. Generally, the studies used biologic markers as the dependent variables. All 11 cross-sectional studies showed a positive relationship between various biomarkers and ENM exposures. Three of the four longitudinal studies showed a negative relationship; the fourth showed positive findings after a 1-year follow-up. Each study considered exposure to ENMs as the independent variable. Exposure was assessed by mass concentration in 10 studies and by particle count in six studies. Six of them assessed both mass and particle concentrations. Some of the studies had limited exposure data because of inadequate exposure assessment. Generally, exposure levels were not very high in comparison to those in human inhalation chamber studies, but there were some exceptions. Most studies involved a small sample size, from 2 to 258 exposed workers. These studies represent the first wave of epidemiological studies of ENM workers. They are limited by small numbers of participants, inconsistent (and in some cases inadequate) exposure assessments, generally low exposures, and short intervals between exposure and effect. Still, these studies are a foundation for future work; they provide insight into where ENM workers are experiencing potentially adverse effects that might be related to ENM exposures.

Cancer Attributable to Asbestos Exposure in Shipbreaking Workers: A Matched-Cohort Study

Purpose

Long-term follow-up studies of asbestos-related cancer in shipbreaking workers are lacking. This study examines the relationship between cancer incidence and asbestos exposure among former Taiwan shipbreaking workers.

Methods

A total of 4,427 shipbreaking workers and 22,135 population-based matched controls were successfully followed in this study. The study cohort was linked to the Taiwan Cancer Registry for new cancer cases. The adjusted hazard ratio (aHR) for cancer was calculated for the shipbreaking workers with Total Exposure Potential Scores (TEP) for asbestos.

Results

Follow-up generated 109,932 person-years, with 940 deaths and 436 cancer cases, among 4,427 shipbreaking workers from 1985 to 2008. The high asbestos exposure group also had a statistically significant increase in the risk of overall cancer (aHR= 1.71; 95% CI: 1.42-2.05), esophagus cancer (aHR= 2.31; 95% CI: 1.00-5.41), liver and intrahepatic bile duct cancer (aHR= 1.60; 95% CI: 1.08-2.36), and trachea, bronchus, and lung cancer (aHR= 3.08; 95% CI: 1.80-5.25). Mesothelioma cases were found in the high asbestos exposure group. Moreover, overall cancer, esophagus cancer, and trachea, bronchus, and lung cancer were seen in a dose-dependent relationship with asbestos exposure.

Conclusions

This study presented the elevated trend of asbestos exposure with cancer incidence for overall cancer, esophagus cancer, and trachea, bronchus, and lung cancer among shipbreaking workers. Those workers previously exposed to asbestos should receive persistent monitoring in order to early detect adverse health outcomes.

The Association between Obstructive Sleep Apnea and Metabolic Markers and Lipid Profiles

Purpose

The purpose of this study was to investigate the association between apnea-hypopnea index (AHI) and metabolic markers and whether the elevated risk of Metabolic Syndrome (MetS) is related to Obstructive Sleep Apnea (OSA).

Methods

This cross-sectional study recruited 246 male bus drivers from one transportation company in Taiwan. Each participant was evaluated by a polysomnography (PSG) test and by blood lipids examination. Severity of OSA was categorized according to the apnea-hypopnea index (AHI).

Results

The results showed that a 73.3% prevalence of MetS in OSA (AHI > 15) and a 80.0% prevalence of MetS in severe OSA (AHI > 30) were found. After adjusting for confounding variables, an increased level of Body-Mass Index (BMI) and two non-MetS cardiovascular risk factors, total cholesterol/HDL-C ratio and TG/HDL-C ratio was significantly associated with AHI in subjects with severe OSA. MetS was about three times to be present in subjects with severe OSA, even adjusted for BMI.

Conclusions

The findings showed a high prevalence of MetS in OSA among professional drivers, especially in the severe group category. BMI was the major contributing factor to OSA. However, the present study did not find a sensitive clinical marker of a detrimental metabolic profile in OSA patients.

Nickel may contribute to EGFR mutation and synergistically promotes tumor invasion in EGFR-mutated lung cancer via nickel-induced microRNA-21 expression

We recently reported that nickel accumulation in lung tissues may be associated with an increased in p53 mutation risk via reduced DNA repair activity. Here, we hypothesized that nickel accumulation in lung tissues could contribute to EGFR mutations in never-smokers with lung cancer. We enrolled 76 never-smoking patients to evaluate nickel level in adjacent normal lung tissues by ICP-MS. The prevalence of EGFR mutations was significantly higher in the high-nickel subgroup than in the low-nickel subgroup. Intriguingly, the OR for the occurrence of EGFR mutations in female, adenocarcinoma, and female adenocarcinoma patients was higher than that of all patients. Mechanistically, SPRY2 and RECK expressions were decreased by nickel-induced miR-21 via activation of the EGFR/NF-κB signaling pathway, which promoted invasiveness in lung cancer cells, and particularly in the cells with EGFR L858R expression vector transfection. The patients' nickel levels were associated with miR-21 expression levels. Kaplan-Meier analysis revealed poorer overall survival (OS) and shorter relapse free survival (RFS) in the high-nickel subgroup than in low-nickel subgroup. The high-nickel/high-miR-21 subgroup had shorter OS and RFS periods when compared to the low-nickel/low-miR-21 subgroup. Our findings support previous epidemiological studies indicating that nickel exposure may not only contribute to cancer incidence but also promote tumor invasion in lung cancer.

Does Social Health Insurance Close the Gap: The Case of Socioeconomic Status and Preterm Low-Birth-Weight Survival

Using a retrospective cohort study design, we report empirical evidence on the effect of parental socioeconomic status, primary care, and health care expenditure associated with preterm or low-birth-weight (PLBW) babies on their mortality (neonatal, postneonatal, and under-5 mortality) under a universal health care system. A total of 4668 singleton PLBW babies born in Taiwan between January 1 and December 31, 2001, are extracted from a population-based medical claims database for a follow-up of up to 5 years. Multivariate survival models suggest the positive effect of higher parental income is significant in neonatal period but diminishes in later stages. Consistent inverse relationship is observed between adequate antenatal care and the three outcomes: neonatal hazard ratio (HR) = 0.494, 95% confidence interval (CI) = 0.312 to 0.783; postneonatal HR = 0.282, 95% CI = 0.102 to 0.774; and under-5 HR = 0.575, 95% CI = 0.386 to 0.857. Primary care services uptake should be actively promoted, particularly in lower income groups, to prevent premature PLBW mortality.

Predictors for Progression of Sleep Disordered Breathing among Public Transport Drivers: A 3-Year Follow-Up Study

STUDY OBJECTIVES

Sleep-disordered breathing (SDB) is associated with an increased risk of motor vehicle crashes. This study aimed to understand SDB progression and related factors among professional drivers.

METHODS

A total of 524 professional male drivers from a transportation company were included in this study. These drivers completed overnight in-home pulse oximetry studies both in 2006 and in 2009. Participants with abnormal results (oxygen desaturation index [ODI] ≥ 10 events/h) comprised the SDB group. Data included questionnaire information on demographics, medical history, SDB symptoms, and anthropometric measurements.

RESULTS

A total of 318 male workers were recruited for further analysis. Fifty of these workers belonged to the SDB group. Workers with untreated SDB significantly progressed to a more severe state after three years. Baseline body mass index (BMI), baseline ODI, and change in BMI were all significant positive predictors of SDB progression (β = 0.823, 0.242, and 1.626; p = 0.047, 0.013, and 0.004, respectively). Compared with non-SDB drivers, SDB subjects showed a greater proportion of newly diagnosed cardiovascular disease (38.0%) at follow-up.

CONCLUSIONS

Untreated SDB was a gradually progressive disorder in professional drivers over a three-year period. Subjects with high BMI and moderate to severe SDB should be closely monitored to allow for early detection of worsening SDB. Weight control should be highlighted in the management of SDB.

COMMENTARY

A commentary on this article appears in this issue on page 409.

Nickel accumulation in lung tissues is associated with increased risk of p53 mutation in lung cancer patients

Occupational exposure to nickel compounds has been associated with lung cancer. The correlation between high nickel levels and increased risk of lung cancer has been previously reported in a case-control study. This study assessed whether nickel exposure increased the occurrence of p53 mutations due to DNA repair inhibition by nickel. A total of 189 lung cancer patients were enrolled to determine nickel levels in tumor-adjacent normal lung tissues and p53 mutation status in lung tumors through atomic absorption spectrometry and direct sequencing, respectively. Nickel levels in p53 mutant patients were significantly higher than those in p53 wild-type patients. When patients were divided into high- and low-nickel subgroups by median nickel level, the high-nickel subgroup of patients had an odds ratio (OR) of 3.25 for p53 mutation risk relative to the low-nickel subgroup patients. The OR for p53 mutation risk of lifetime non-smokers, particularly females, in the high-nickel subgroup was greater than that in the low-nickel subgroup. To determine whether nickel affected DNA repair capacity, we conducted the host cell reactivation assay in A549 and H1975 lung cancer cells and showed that the DNA repair activity was reduced by nickel chloride in a dose-dependent manner. This was associated with elevated production of hydrogen peroxide-induced 8-oxo-deoxyguanosine. Therefore, increased risk of p53 mutation due to defective DNA repair caused by high nickel levels in lung tissues may be one mechanism by which nickel exposure contributes to lung cancer development, especially in lifetime female non-smokers.

Monitoring of PAEMs and beta-agonists in urine for a small group of experimental subjects and PAEs and beta-agonists in drinking water consumed by the same subjects

This 5-month study contains two parts: (1) to monitor the concentrations of 11 phthalate esters metabolites (PAEMs) and two beta-agonists in human urine samples collected from a small group of consented participants including 16 females and five males; and (2) to analyze the residues of phthalate esters (PAEs) and beta-agonists in various categories of drinking water consumed by the same group of subjects. Each category of human urine and drinking water had 183 samples of its own. The analytical results showed that nine PAEMs were detected in human urine and eight PAEs were detected in drinking water samples. It was found that average concentrations of PAEMs increased as the age increased, but no significant difference between sexes. Further, using the principal component analysis, the loadings of age effect were found to be two times greater than that of gender effect in terms of four DEHP metabolites. Regarding beta-agonists of concern (i.e., ractopamine and salbutamol), they were neither detected in human urine nor drinking water samples in this study.

Cancer incidence of Taiwanese shipbreaking workers who have been potentially exposed to asbestos

BACKGROUND

Shipbreaking remains one of the most dangerous jobs worldwide. Shipbreaking workers are exposed to many hazardous chemicals, especially asbestos. Unfortunately, long-term follow-up studies of cancer incidence patterns in shipbreaking workers are lacking. This study examines whether there is an increased risk of cancer among male shipbreaking workers over a 24-year follow-up period.

METHODS

4155 male shipbreaking worker's information was retrospectively collected from Kaohsiung's Shipbreaking Workers Union database from 1985. The study cohort was linked to the Taiwan Cancer Registry from 1985 to 2008 for new cancer cases. The expected number of cancers for shipbreaking workers was calculated by using the age (5-year intervals) and calendar time-specific annual rates of cancer incidence with reference to the general population of Taiwan from 1985 to 2008. Standardized incidence ratios (SIRs) were calculated as relative risk estimates. The hazard ratio (HR) for cancer was calculated for the shipbreaking workers with Total Exposure Potential Scores for asbestos.

RESULTS

After consideration of a 5-year latency period, an elevated incidence of overall cancer (N=368; SIR=1.13 (1.01-1.25)), oral cavity cancer (N=83; SIR=1.99 (1.58-2.46)), and trachea, bronchus, and lung cancers (N=53; SIR=1.36 (1.02-1.78)) was found among male shipbreaking employees. Moreover, mesothelioma cases were found in those who had the occupation of flame cutter. The high asbestos exposure group was associated with an increased SIR of developing overall cancer and oral cancer, whether we considered a 5-year or 10-year latency period.

CONCLUSION

Asbestos-related diseases, including lung cancer and mesothelioma, were seen in excess in these shipbreaking workers and some cases appeared to have a dose-dependent relationship. Preventative measures among male shipbreaking workers should be researched further.

The effects of fine particulate air pollution on daily mortality: a case-crossover study in a subtropical city, Taipei, Taiwan

This study was undertaken to determine whether there was an association between PM_2.5 levels and daily mortality in Taipei, Taiwan, the largest metropolitan city with a subtropical climate. Daily mortality, air pollution, and weather data for Taipei were obtained for the period from 2006–2008. The relative risk of daily mortality was estimated using a time-stratified case-crossover approach, controlling for weather variables, day of the week, seasonality, and long-term time trends. For the single pollutant model, PM_2.5 showed association with total mortality both on warm (>23 °C) and cool days (<23 °C). There is no indication of an association between PM_2.5 and risk of death due to respiratory diseases both on warm and cool days. PM_2.5 had effects on the risk of death from cardiovascular diseases only on cool days. In the two-pollutant models, PM_2.5 remained effects on the risk of mortality for all cause and cardiovascular disease after the inclusion of SO₂ and O₃ both on warm and cool days. This study provides evidence that short-term exposure to PM_2.5 increased the risk of death for all cause and cardiovascular disease.

High job strain is associated with inflammatory markers of disease in young long-haul bus drivers

Atherosclerosis is an inflammatory disease. The study was aimed to investigate the association between job strain and inflammation markers and to examine factors contributing to high strain. The long-haul bus drivers (n = 825) were recruited from a Taiwanese transportation company. The psychosocial work environment was measured by a validated job content questionnaire (JCQ). Plasma high sensitivity C-reactive protein (hs-CRP) and homocysteine (Hcy) were analyzed as inflammation markers. Job strain effects and its interaction with age were analyzed by logistic regression. Explained variance (Nagelkerke R square) was applied to select important stressors. The crude and adjusted odds ratio (OR) for the effect of high strain on high hs-CRP and Hcy were not significant. However, there was significant interaction between job strain and age (p = .014). The significantly increased risk of high strain on high hs-CRP was found among drivers younger than 35 years old (OR = 2.71), but not in driver groups age 35 to 49 and older than 50. The contributing factors to high strain were varied among the 3 age groups. The 3 stressors found for young drivers were having rest time less than 8 hours between 2 shifts, being physically inactive during leisure time, and frequent driving more than 12 hours a day. Job strain interacted with age influenced hs-CRP levels. The risk of inflammatory disease markers only increased in high strained group of young drivers. Appropriate work shift systems should be implemented to increase off-duty time, reduce sleep restrictions, and increase physical activity during leisure time.

Short-term effects of fine particulate air pollution on hospital admissions for respiratory diseases: a case-crossover study in a tropical city

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for respiratory diseases in Kaohsiung, Taiwan. Hospital admissions for respiratory diseases including pneumonia, asthma, and chronic obstructive pulmonary disease (COPD) and ambient air pollution data for Kaohsiung were obtained for the period 2006-2010. The relative risk (RR) of hospital admissions for respiratory diseases was estimated using a case-crossover approach, controlling for weather variables, day of the week, seasonality, and chronic time trends. For the single-pollutant model (without adjustment for other pollutants), increased number of admissions for respiratory diseases were significantly associated with higher PM2.5 levels only on cool days (<25°C), with an interquartile range rise associated with a 50 (95% CI% = 45-55%), 40% (95% CI = 25-58%), and 46% (95% CI = 36-57%) elevation in frequency of admissions for pneumonia, asthma, and COPD, respectively. In the two-pollutant models, PM2.5 levels remained significant even controlling for sulfur dioxide, nitrogen dioxide, carbon monoxide, or ozone on cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for respiratory diseases in Taiwan.

Androgenic alopecia is associated with less dietary soy, lower [corrected] blood vanadium and rs1160312 1 polymorphism in Taiwanese communities

Background

Although the genetic basis of androgenic alopecia has been clearly established, little is known about its non-genetic causes, such as environmental and lifestyle factors.

Objective

This study investigated blood and urine heavy metals concentrations, environmental exposure factors, personal behaviors, dietary intakes and the genotypes of related susceptibility genes in patients with androgenic alopecia (AGA).

Design

Age, AGA level, residence area, work hours, sleep patterns, cigarette usage, alcohol consumption, betel nut usage, hair treatments, eating habits, body heavy metals concentrations and rs1998076, rs913063, rs1160312 and rs201571 SNP genotype data were collected from 354 men. Logistic regression analysis was performed to examine whether any of the factors displayed odds ratios (ORs) indicating association with moderate to severe AGA (≧IV). Subsequently, Hosmer-Lemeshow, Nagelkerke R² and accuracy tests were conducted to help establish an optimal model.

Results

Moderate to severe AGA was associated with the AA genotype of rs1160312 (22.50, 95% CI 3.99–126.83), blood vanadium concentration (0.02, 95% CI 0.01–0.04), and regular consumption of soy bean drinks (0.23, 95% CI 0.06–0.85), after adjustment for age. The results were corroborated by the Hosmer-Lemeshow test (P = 0.73), Nagelkerke R² (0.59), accuracy test (0.816) and area under the curve (AUC; 0.90, 0.847–0.951) analysis.

Conclusions

Blood vanadium and frequent soy bean drink consumption may provide protect effects against AGA. Accordingly, blood vanadium concentrations, the AA genotype of rs1160312 and frequent consumption of soy bean drinks are associated with AGA.

Crucial role of Toll-like receptors in the zinc/nickel-induced inflammatory response in vascular endothelial cells

Our previous studies indicated that zinc induced inflammatory response in both vascular endothelial cells and promonocytes. Here, we asked if other metals could cause the similar effect on vascular endothelial cells and tried to determine its underlying mechanism. Following screening of fifteen metals, zinc and nickel were identified with a marked proinflammatory effect, as determined by ICAM-1 and IL-8 induction, on human umbilical vein endothelial cells (HUVECs). Inhibiting protein expression of myeloid differentiation primary response protein-88 (MyD88), a Toll-like receptor (TLR) adaptor acting as a TLR-signaling transducer, significantly attenuated the zinc/nickel-induced inflammatory response, suggesting the critical roles of TLRs in the inflammatory response. Blockage of TLR-4 signaling by CLI-095, a TLR-4 inhibitor, completely inhibited the nickel-induced ICAM-1 and IL-8 expression and NFκB activation. The same CLI-095 treatment significantly blocked the zinc-induced IL-8 expression, however with no significant effect on the ICAM-1 expression and a minor inhibitory effect on the NFκB activation. The finding demonstrated the differential role of TLR-4 in regulation of the zinc/nickel-induced inflammatory response, where TLR-4 played a dominant role in NFκB activation by nickel, but not by zinc. Moreover, inhibition of NFκB by adenovirus-mediated IκBα expression and Bay 11-7025, an inhibitor of cytokine-induced IκB-α phosphorylation, significantly attenuated the zinc/nickel-induced inflammatory responses, indicating the critical of NFκB in the process. The study demonstrates the crucial role of TLRs in the zinc/nickel-induced inflammatory response in vascular endothelial cells and herein deciphers a potential important difference in NFκB activation via TLRs. The study provides a molecular basis for linkage between zinc/nickel exposure and pathogenesis of the metal-related inflammatory vascular disease.

Mortality among shipbreaking workers in Taiwan--a retrospective cohort study from 1985 to 2008

BACKGROUND

Shipbreaking workers are typically exposed to a wide range of hazardous chemicals. However, long-term follow-up studies of their mortality patterns are lacking. This study examined mortality among shipbreaking workers over a 24-year follow-up period.

METHODS

A total of 4,962 shipbreaking workers were recruited from the database of the Kaohsiung Shipbreaking Workers Union. The data were then linked to the Taiwan National Death Registry from 1985 to 2008. The mortality ratios-standardized for age and calendar years-(SMRs) for various causes of deaths were calculated with reference to the general population of Taiwan.

RESULTS

Among men workers, a statistically significant increased SMR was observed for all causes (SMR = 1.28), all cancers (SMR = 1.26; particularly noteworthy for lesions of oral and nasopharyngeal: SMR 2.03, liver: SMR 4.63, and lung: SMR 1.36), cirrhosis of the liver (SMR = 1.32), and accidents (SMR = 1.91). A statistically significant increase in mortality was observed for respiratory system cancer (SMR = 1.87) and lung cancer (SMR = 1.91) among workers with a longer duration of employment (≥7 years). The result also showed that among shipbreaking workers who were still alive, two people had mesothelioma and 10 people have asbestosis.

CONCLUSIONS

Those employed in shipbreaking industries experienced an increase in mortality from all causes. The increased SMR for lung cancer was probably related to asbestos, metals, and welding fume exposure.

Rapid and intermediate N-acetylators are less susceptible to oxidative damage among 4,4'-methylenebis(2-chloroaniline) (MBOCA)-exposed workers

OBJECTIVES

In this study, we explored the association between a marker of oxidative stress, 8-hydroxydeoxyguanosine (8-OHdG), and genetic polymorphism of the carcinogen-metabolizing enzyme N-acetyltransferase 2 (NAT2) among 4,4'-methylenebis(2-chloroaniline) (MBOCA)-exposed workers.

METHODS

The study population was recruited from four MBOCA-producing factories, and included 57 MBOCA-exposed workers and 101 unexposed control workers. Personal characteristics were collected by questionnaire. Plasma 8-OHdG levels were measured by LC/MS/MS. NAT2 alleles were measured by polymerase chain reaction-based restriction fragment length polymorphism (PCR-RFLP).

RESULTS

NAT2 polymorphism influenced the plasma 8-OHdG levels of MBOCA-exposed workers, but not of non-exposed workers. No difference between exposed and control groups was found for the crude 8-OHdG levels among rapid, intermediate, and slow acetylators. After adjusting for gender, age, smoking, and alcohol consumption habit, the 8-OHdG concentration in the MBOCA-exposed workers was 0.18pg/ml (95% CI -1.80 to -0.12) lower than the control group among rapid and intermediate acetylators. However, the difference between exposed and control groups was not significant for slow acetylators.

CONCLUSION

Gene-environment interactions could play a role in the carcinogenesis of occupational MBOCA exposure. We suggest that the impact of the NAT2 acetylator status is low, if at all, on the generation of the oxidative stress marker 8-OHdG in the investigated exposed group.

Exposure to cooking oil fumes and oxidative damages: a longitudinal study in Chinese military cooks

Cooking oil fumes (COF) contain polycyclic aromatic hydrocarbons (PAHs), heterocyclic aromatic amines, benzene, and formaldehyde, which may cause oxidative damages to DNA and lipids. We assessed the relations between exposure to COF and subsequent oxidative DNA damage and lipid peroxidation among military cooks and office-based soldiers. The study population, including 61 Taiwanese male military cooks and a reference group of 37 office soldiers, collected urine samples pre-shift of the first weekday and post-shift of the fifth workday. We measured airborne particulate PAHs in military kitchens and offices and concentrations of urinary 1-OHP, a biomarker of PAH exposure, urinary 8-hydroxydeoxyguanosine (8-OHdG), a biomarkers of oxidative DNA damage, and urinary isoprostane (Isop). Airborne particulate PAHs levels in kitchens significantly exceeded those in office areas. The concentrations of urinary 1-OHP among military cooks increased significantly after 5 days of exposure to COF. Using generalized estimating equation analysis adjusting for confounding, a change in log(8-OHdG) and log(Isop) were statistically significantly related to a unit change in log(1-OHP) (regression coefficient (β), β=0.06, 95% CI 0.001-0.12) and (β=0.07, 95% CI 0.001-0.13), respectively. Exposure to PAHs, or other compounds in cooking oil fumes, may cause both oxidative DNA damage and lipid peroxidation.

Fine particulate air pollution and hospital admissions for myocardial infarction in a subtropical city: Taipei, Taiwan

This study was undertaken to determine whether there was a correlation between fine particles (PM2.5) levels and hospital admissions for myocardial infarction (MI) in Taipei, Taiwan. Hospital admissions for MI and ambient air pollution data for Taipei were obtained for the period 2006-2010. The relative risk of hospital admissions for MI was estimated using a casecrossover approach, controlling for weather variables, day of the week, seasonality, and longterm time trends. For the single-pollutant model (without adjustment for other pollutants), increased numbers of MI admissions were significantly associated with higher PM2.5 levels both on warm days (>23°C) and on cool days (<23°C). This was accompanied by an interquartile range elevation correlated with a 10% (95% CI = 6-15%) and 5% (95% CI = 1-9%) rise in number of MI admissions, respectively. In the two-pollutant models, PM2.5 remained significant after inclusion of SO2 or O3 on both warm and cool days. This study provides evidence that higher levels of PM2.5 increase the risk of hospital admissions for MI.

Exposure to heavy metals and polycyclic aromatic hydrocarbons and DNA damage in taiwanese traffic conductors

BACKGROUND

Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAH) and heavy metals, has been associated with the etiology and prognosis of many illnesses. However, the specific causal agents and underlying mechanisms for different health outcomes remain unclear. The aims of this study were to assess the relations between urinary biomarkers of exposure to PAHs (1-hydroxypyrene-glucuronide, 1-OHPG) and heavy metals (cadmium, Cd; nickel, Ni; arsenic, As; lead, Pb; and copper, Cu) and the effect of their interaction on DNA damage (8-oxo-7,8-dihydro-guanine, 8-oxodG).

METHODS

We recruited 91 traffic conductors and 53 indoor office workers between May 2009 and June 2011 in Taipei, Taiwan. Postshift urine samples from 2 consecutive days were analyzed for 1-OHPG, Cd, Ni, As, Pb, Cu, and 8-oxodG. To estimate the effects from PAHs and metals on DNA damage, we constructed a linear mixed model adjusted for confounding variables.

RESULTS

We found that urinary 1-OHPG and Cd levels were independent predictors of urinary 8-oxodG levels (β = 0.112; P = 0.015 for 1-OHPG; β = 0.138; P = 0.031 for urinary Cd). The joint effect of urinary 1-OHPG and Cd levels was associated with urinary 8-oxodG levels (P = 0.001).

CONCLUSIONS

Co-exposure to environmental PAHs and Cd could cause oxidative DNA damage.

IMPACT

These findings suggest that the additive interaction between exposure to environmental PAHs and Cd could enhance the burden of oxidative stress.

Abstract 39: Exposure to heavy metals and polycyclic aromatic hydrocarbons and DNA damage in Taiwanese traffic conductors

Introduction: Exposure to traffic-related air pollutants, including polycyclic aromatic hydrocarbons (PAHs) and heavy metals, has been associated with the etiology and prognosis of many illnesses. However, the specific causal agents and underlying mechanisms for different health outcomes remain unclear. The aims of this study were to assess the relations between urinary biomarkers of exposure to PAHs (1-hydroxypyrene-glucuronide, 1-OHPG) and heavy metals (cadmium, Cd; nickel, Ni; arsenic, As; lead, Pb; copper, Cu) and their interaction effect on DNA damage (8-oxo-7,8-dihydro-guanine, 8-oxodG).

Methods: We recruited 91 traffic conductors and 53 indoor office workers between May 2009 and June 2011 in Taipei, Taiwan. Post-shift urine samples from 2 consecutive days were analyzed for 1-OHPG, Cd, Ni, As, Pb, Cu and 8-oxodG. To estimate the effects from PAHs and metals on DNA damage, we constructed a linear mixed model adjusted for confounding variables.

Results: We found that urinary 1-OHPG and Cd levels were independent predictors of urinary 8-oxodG levels (β=0.112, p=0.015 for 1-OHPG; β=0.138, p=0.031 for urinary Cd). The joint effect of urinary 1-OHPG and Cd levels was associated with urinary 8-oxodG levels (p=0.001).

Conclusions: Co-exposure to environmental PAHs and Cd could cause oxidative DNA damage. These findings suggest that the additive interaction between exposure to environmental PAHs and Cd could enhance the burden of oxidative stress.

Citation Format: Han-Bin Huang, Guan-Wen Chen, Chien-Jen Wang, Yong-Yang Lin, Saou-Hsing Liou, Ching-Huang Lai, Shu-Li Wang. Exposure to heavy metals and polycyclic aromatic hydrocarbons and DNA damage in Taiwanese traffic conductors. [abstract]. In: Proceedings of the AACR Special Conference on Post-GWAS Horizons in Molecular Epidemiology: Digging Deeper into the Environment; 2012 Nov 11-14; Hollywood, FL. Philadelphia (PA): AACR; Cancer Epidemiol Biomarkers Prev 2012;21(11 Suppl):Abstract nr 39.