Association of folate deficiency and selected tumor marker concentrations in long-term hexavalent chromium exposed population.

Both hexavalent chromium [Cr (VI)] exposure and folate deficiency have been associated with increased cancer risks. Our previous studies have found folate deficiency in Cr (VI) exposed population. Here the relationship between some tumor markers and folate status in long-term Cr (VI) exposure was investigated carefully to show the multiple aspects of Cr (VI) carcinogenesis. A group of 115 workers occupationally exposed to chromate and 60 matched, unexposed controls in Shandong province of China were recruited. Environmental and biological exposure assessments including personal exposure to airborne Cr and Cr contents in erythrocytes were performed. Serum folate, plasma total homocysteine (tHcy) and plasma carcinoembryonic antigen (CEA), neuron specific enolase (NSE), squamous cell carcinoma antigen (SCC), cytokeratin fragment antigen 21-1 (CYFRA 21-1), cancer antigen 72-4 (CA72-4), as well as α-fetoprotein (AFP) were measured. Smoking index (SI) was also calculated to discriminate possible confounding effects of smoking status. Serum folate level decreased significantly, while plasma tHcy, CEA, NSE, SCC, CYFRA21-1, CA72-4 and AFP concentrations increased significantly after Cr (VI) exposure. Meanwhile, plasma CEA, NSE and SCC were negatively correlated with serum folate. SI was negatively correlated with serum folate but positively correlated with plasma tHcy, CEA and NSE levels. Present study suggests that folate deficiency was associated with increased cancer risks and might be affected by smoking in Cr (VI) exposed population. Folate might play a key role in Cr (VI) carcinogenesis although further detailed investigations are needed to clarify the mechanism of this process.

[Evidence-based study of chromate exposed workers' health surveillance indexes].

OBJECTIVE: The health surveillance proposal for chromate exposed workers was provided and analyzed on the evidence-based study and then to be improved. METHOD: Firstly, the related literatures were searched about liver damage, micronuclei, urinary chromium and hexavalent chromium exposure in Evidence Based Medicine Reviews such as Cochran library, OVID Medline, Web of knowledge in December 2011; and then, these literatures were reviewed in according to inclusion and exclusion criteria; 22 articles totally were retrieved, evaluated and classified in according to the grading standard by Oxford Centre for Evidence-based Medicine.Finally, field epidemiological investigation was further adopted to confirm the efficiency and feasibility of this proposal, combined with cost-effectiveness analysis:the ratio of total cost divided survival years was used to express the cost-effectiveness. RESULT: Only the glutamic pyruvic transaminase test could not reflect liver damage caused by chromate exposure well; Urinary chromium correlated well with the index reflecting body damage caused by chromate exposure; Binucleated cells micronucleus index in peripheral blood lymphocyte could reflect the genetic damage caused by chromate exposure. As for health economic evaluation of chromate lung cancer, the value of cost/effectiveness was ¥42 321.61 per year that was far below the value of common people (¥252 868.97 per year) . CONCLUSION: It was suggested that serum glutamic pyruvic transaminase test should be replaced by liver function test, urinary chromium should be classified as a compulsory index and binucleated cells micronucleus index in peripheral blood lymphocyte should be supplied as a recommended index.

[Impact of specimen collection and storage consumable products on trace element quantitative analysis].

OBJECTIVE: This study aimed to explore the impact of specimen collection and storage consumable products on trace element quantitative analysis. METHODS: Devices and consumable products of different brands used in specimen collection or storage were selected and treated separately as below:urine collection and storage tubes (Brand A, B, C and D, 2 samples for each brand) were treated with 1% of HNO(3) volume fraction for 2 - 4 h; blood taking device (Brand O, P and Q, 3 samples for each brand) were used for ultra-pure water samples collecting as simulation of blood sampling;dust sampling filters (Brand X, Y and Z, 2 samples for each brand) were cold digested by nitric acid for 12 h, followed by microwave digestion. Then cadmium, cobalt, chromium, copper, iron, manganese, molybdenum, nickel, lead, selenium, stannum, titanium, vanadium and zinc concentrations in the solutions obtained during the course of collect or storage were quantified by inductively coupled plasma mass spectrometer. RESULTS: For the urine collection and storage consumable products, background values of elements were described as mean of parellel samples. The consentration of 14 quantified elements were relatively low for 5 ml cryogenic vials (brand B) with background values range of 0.001 - 0.350 ng/ml. The background values of copper of 50 ml centrifuge tubes (brand A), chromium of 5 ml cryogenic vials (brand C) and zinc of 1.5 ml centrifuge tubes (brand D) were relatively high, which were 1.900, 1.095 and 1.368 ng/ml, respectively. Background values of elements in blood sampling devices were described as x(-) ± s. Background values of chromium for brand O, P and Q were (0.120 ± 0.017), (0.337 ± 0.093) and (0.360 ± 0.035) ng/ml; for copper were (0.050 ± 0.001), (0.017 ± 0.012) and (0.103 ± 0.015) ng/ml; for lead were (0.057 ± 0.072), (0.183 ± 0.118) and (0.347 ± 0.006) ng/ml; for titanium were (7.883 ± 0.145), (8.863 ± 0.190) and (8.613 ± 0.274) ng/ml; zinc were (2.240 ± 0.573), (42.140 ± 22.756) and (8.850 ± 3.670) ng/ml. There were statistically differences of background values for chromium, copper, lead, titanium and zinc among the above three brands of blood sampling devices (all P values < 0.05). For air sampling filters, background values of elements were described as mean of parellel samples. Background values of chromium and nickel of sampling filters (brand X) were lowest, which were 17.000 and 15.400 ng per piece, respectively; while background values for other elements were relatively high, the quantification of cadmium, cobalt, copper, iron, manganese, molybdenum, lead, selenium, stannum, titanium, vanadium and zinc were 0.250, 0.550, 48.500, 690.000, 25.500, 0.900, 6.500, 10.550, 7.950, 10.500, 0.850, 370.000 ng per piece, respectively. Background values of chromium and nickel of sampling filters (brand Z) were highest, which were 171.000 and 29.850 ng per piece. CONCLUSION: Background values of trace elements varied among products of different brands, and the most noticable differences were found in chromium, manganese, nickel, lead, stannum and zinc.

[Dynamic observation of pulmonary ventilation function in workers contacting chromate].

OBJECTIVE: To explore changes of pulmonary ventilation function of chromate exposed workers. METHODS: Ninety-five chromate exposed workers were used as exposure group, and forty-two workers without chromate exposure as control group. Pulmonary ventilation function was performed two times in the winter of 2010 and 2011 respectively in one chromate manufactured factory in Henan Province. RESULTS: In 2010, pulmonary ventilation function of chromate exposed group compared with the control group, forced vital capacity [FVC, (75.38±15.23) L vs. (83.99±26.52)L], forced expiratory volume in one second [FEV1,(82.13±16.51)L vs.(91.24±30.03)L], FEV1/FVC(112.10±13.23 vs. 116.18±11.32), peak expiratory flow [PEF,(74.31±28.09) L/s vs.(78.13±28.34)L/s], maximal expiratory flow [MEF,(101.23±46.37) L/s vs. (110.02±41.40)L/s], maximum ventilation volume [MVV,(90.82± 16.89)L/min vs. (99.95±22.61)L/min]were significantly decreased(P<0.05). In 2011, pulmonary ventilation function of chromate exposed group compared with the control group, FVC[(72.34±14.18)L vs.(81.01±20.79)L], FEV1[(76.04±16.20)L vs.(86.71±24.53)L], FEV1/FVC(109.10±16.18 vs.114.08±10.79), PEF[(71.35±24.87 )L/s vs.(75.36±20.67)L/s], MEF[(96.51±30.17)L/s vs.(107.11±34.81)L/s], MVV[(84.85±21.22)L/min vs. (96.77±22.63)L/min] were also significantly decreased(P<0.05). 2011 compared with 2010, pulmonary ventilation function of chromate exposed group FEV1[(76.04±16.20)L vs.( 82.13±16.51)L], MEF[(96.51±30.17)L/s vs. (101.23±46.37)L/s], MVV[(84.85±21.22)L/min vs. (90.82±16.89)L/min] were significantly decreased(P<0.05). Comparing the classification and category of pulmonary dysfunction based on FVC, FEV1, FVC/ FEV1, no difference was found for classification between the two groups and the category of pulmonary dysfunction almost belongs to limit type, which did not change with exposed time. CONCLUSION: Chronic chromate exposure can cause significant effects on pulmonary function of the workers, and the types of work in production can affect the results.

Oxidative DNA damage and global DNA hypomethylation are related to folate deficiency in chromate manufacturing workers.

Exposure to hexavalent chromium [Cr (VI)] can cause DNA damage, genetic instability and increase the risk of cancer development. Folate deficiency affects DNA methylation and reduces the stability of the genetic material. However, the correlation between folate deficiency and DNA damage has never been clearly elucidated in chromate workers. In this study, we recruited one hundred and fifteen workers from chromate producing facilities as testing subjects and sixty local residents without chromium exposure history served as controls. The results showed an evident accumulation of Cr in peripheral red blood cells accompanied by a significantly decreased serum folate in chromate exposed workers. The decreased serum folate was associated with an increased urinary 8-hydroxy-2'-deoxyguanosine, DNA strand breaks and global DNA hypomethylation. These findings suggest that chronic occupational chromate exposure could induce folate depletion, which may further promote DNA damages and global DNA hypomethylation. Adequate folate supplement may provide benefit to chromate sufferers in stabilization of genetic material and reduce the risk of cancer development.