Cytogenetic and immunological effects associated with occupational formaldehyde exposure

The formation of SCEs as an effect of occupational exposure to formaldehyde

Formaldehyde (FA) is a ubiquitous toxic chemical employed worldwide due to its disinfectant and preservative properties. Despite being classified as a human carcinogen, FA is still employed as formalin in pathology wards as standard fixative. We evaluated its relationship with the formation of sister-chromatid exchanges (SCEs) in cultured peripheral blood lymphocytes on 57 pathologists and 48 controls and the risk/protective role played by several genetic polymorphisms. All subjects were assessed for SCEs and genotyped for the most common cancer-associated gene polymorphisms: CYP1A1 exon 7 (A > G), CYP1A1*2A (T > C), CYP2C19*2 (G > A), GSTT1 (presence/absence), GSTM1 (presence/absence), GSTP1 (A > G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα − 308 G > A), IL10 − 1082 (G > A), and IL6 − 174 (G > C). Air-FA concentration was assessed through passive personal samplers. Pathologists, exposed to 55.2 μg/m³ of air-FA, showed a significantly higher SCEs frequency than controls, exposed, respectively, to 18.4 μg/m³. Air-FA was directly correlated with SCEs frequency and inversely with the replication index (RI). Regression models showed FA exposure as a significant predictor in developing SCEs, while did not highlight any role of the selected polymorphisms. Our study confirms the role of low air-FA levels as genotoxicity inductor, highlighting the importance to define exposure limits that could be safer for exposed workers.

The role of phase I, phase II, and DNA-repair gene polymorphisms in the damage induced by formaldehyde in pathologists

Formaldehyde (FA) is a human carcinogen used as formalin in hospital laboratories. We evaluated its association with human chromosomal aberrations (CAs) and the risk/protective role played by several genetic polymorphisms in this relationship, on a cohort of 57 exposed pathologists vs 48 controls. All subjects were assessed for CAs on peripheral blood lymphocytes and genotyped for the most common cancer-associated gene polymorphisms which could be related with the genotoxic outcome: CYP1A1 exon 7 (A>G), CYP1A1*2A (T>C), CYP2C19*2 (G>A), GSTT1 (Positive/Null), GSTM1 (Positive/null), GSTP1 (A>G), XRCC1 (G399A), XRCC1 (C194T), XRCC1 (A280G), XPD (A751C), XPC exon 15 (A939C), XPC exon 9 (C499T), TNFα - 308 (G>A), IL10 - 1082 (G>A), IL10 - 819 (C>T) and IL6 - 174 (G>C). Air-FA concentration was assessed through personal samplers. The comparison between pathologists and controls showed a significantly higher CAs frequency in pathologists. Significant positive correlations were found between CAs frequency and air-FA concentration while significant associations were found between variation in CAs frequency and the mutated allele for CYP1A1 exon 7 (A>G), CYP2C19*2 (G>A), GSTT1-positive, GSTM1-positive and XRCC1 (G399A). Our study confirms the role of FA as genotoxicity inductor, even in workers chronically exposed to low air-FA levels and reveals the role played by some genetic polymorphisms in this association, highlighting the importance of individual susceptibility biomarkers assessment in occupational health studies.

Formaldehyde exposure and leukemia risk: a comprehensive review and network-based toxicogenomic approach

Formaldehyde is a widely used but highly reactive and toxic chemical. The International Agency for Research on Cancer classifies formaldehyde as a Group 1 carcinogen, based on nasopharyngeal cancer and leukemia studies. However, the correlation between formaldehyde exposure and leukemia incidence is a controversial issue. To understand the association between formaldehyde exposure and leukemia, we explored biological networks based on formaldehyde-related genes retrieved from public and commercial databases. Through the literature-based network approach, we summarized qualitative associations between formaldehyde exposure and leukemia. Our results indicate that oxidative stress-mediated genetic changes induced by formaldehyde could disturb the hematopoietic system, possibly leading to leukemia. Furthermore, we suggested major genes that are thought to be affected by formaldehyde exposure and associated with leukemia development. Our suggestions can be used to complement experimental data for understanding and identifying the leukemogenic mechanism of formaldehyde.

Susceptibility to COVID-19 in populations with health disparities: Posited involvement of mitochondrial disorder, socioeconomic stress, and pollutants

SARS-CoV-2 is a novel betacoronavirus that has caused the global health crisis known as COVID-19. The implications of mitochondrial dysfunction with COVID-19 are discussed as well as deregulated mitochondria and inter-organelle functions as a posited comorbidity enhancing detrimental outcomes. Many environmental chemicals (ECs) and endocrine-disrupting chemicals can do damage to mitochondria and cause mitochondrial dysfunction. During infection, SARS-CoV-2 via its binding target ACE2 and TMPRSS2 can disrupt mitochondrial function. Viral genomic RNA and structural proteins may also affect the normal function of the mitochondria-endoplasmic reticulum-Golgi apparatus. Drugs considered for treatment of COVID-19 should consider effects on organelles including mitochondria functions. Mitochondrial self-balance and clearance via mitophagy are important in SARS-CoV-2 infection, which indicate monitoring and protection of mitochondria against SARS-CoV-2 are important. Mitochondrial metabolomic analysis may provide new indicators of COVID-19 prognosis. A better understanding of the role of mitochondria during SARS-CoV-2 infection may help to improve intervention therapies and better protect mitochondrial disease patients from pathogens as well as people living with poor nutrition and elevated levels of socioeconomic stress and ECs.

Formaldehído en ambientes laborales: revisión de la literatura y propuesta de vigilancia ocupacional

Introducción. El formaldehído es una sustancia ampliamente usada a nivel industrial; sin embargo, es considerada un agente mutagénico y carcinógeno para los humanos. Para determinar el grado de riesgo de los trabajadores ocupacionalmente expuestos (TOE) al formaldehído, debe hacerse un seguimiento de sus niveles de concentración ambiental y de los biomarcadores que permiten identificar su daño potencial para la salud. En Colombia, lamentablemente, no existen lineamientos respecto a la exposición ocupacional a esta sustancia.Objetivo.Revisar estudios recientes sobre exposición ocupacional a formaldehído para diseñar una estrategia de seguimiento y vigilancia de los TOE a esta sustancia en Colombia.Materiales y métodos. Se realizó una revisión de la literatura en PubMed, MedLine, ScienceDirect y Embase mediante la siguiente estrategia de búsqueda: artículos sobre exposición ocupacional a formaldehído publicados en inglés o español entre 2013 y 2017. Los términos de búsqueda fueron “occupational exposure”, “formaldehyde” “mutagenicity test” y “DNA adducts” y sus equivalentes en español.Resultados. La búsqueda inicial arrojó 103 registros, sin embargo solo 36 artículos cumplieron los criterios de inclusión establecidos.Conclusiones. La gestión adecuada del riesgo derivado de la exposición ocupacional a formaldehido, así como el seguimiento médico apropiado de estos trabajadores, requiere la implementación de una serie de acciones interdisciplinarias que permitan la creación de un sistema de vigilancia ocupacional integral de los TOE a esta sustancia. 

Estimation of formaldehyde occupational exposure limit based on genetic damage in some Iranian exposed workers using benchmark dose method

The present study evaluated an occupational exposure level for formaldehyde employing benchmark dose (BMD) approach. Dose-response relationship was determined by utilizing cumulative occupational exposure dose and DNA damage. Based on this goal, outcome of comet assay for some Iranian exposed people in occupational exposure individuals was used. In order to assess formaldehyde exposure, 53 occupationally exposed individuals selected from four melamine tableware workshops and 34 unexposed subjects as a control group were examined. The occupational exposure dose was carried out according to the NIOSH-3500 method, and the DNA damage was obtained by employing comet assay in peripheral blood cells. EPA Benchmark Dose Software was employed for calculating BMD and BMDL. Cumulative exposure dose of formaldehyde was between of 2.4 and 1972 mg. According to the findings of the current study, the induction of DNA damage in the exposed persons was increased tail length and tail moment (p < 0.001), when compared to controls. Finally, an acceptable dose-response relationship was obtained in three-category information between formaldehyde cumulative exposure doses and genetic toxicity. BMDL was 0.034 mg/m³ (0.028 ppm), corresponding to genetic damage of peripheral blood cells. It can be concluded that the occupational permissible limit in Iranian people could be at levels lower than OSHA standards.

Re-evaluation of the WHO (2010) formaldehyde indoor air quality guideline for cancer risk assessment

In 2010, the World Health Organization (WHO) established an indoor air quality guideline for short- and long-term exposures to formaldehyde (FA) of 0.1 mg/m3 (0.08 ppm) for all 30-min periods at lifelong exposure. This guideline was supported by studies from 2010 to 2013. Since 2013, new key studies have been published and key cancer cohorts have been updated, which we have evaluated and compared with the WHO guideline. FA is genotoxic, causing DNA adduct formation, and has a clastogenic effect; exposure-response relationships were nonlinear. Relevant genetic polymorphisms were not identified. Normal indoor air FA concentrations do not pass beyond the respiratory epithelium, and therefore FA's direct effects are limited to portal-of-entry effects. However, systemic effects have been observed in rats and mice, which may be due to secondary effects as airway inflammation and (sensory) irritation of eyes and the upper airways, which inter alia decreases respiratory ventilation. Both secondary effects are prevented at the guideline level. Nasopharyngeal cancer and leukaemia were observed inconsistently among studies; new updates of the US National Cancer Institute (NCI) cohort confirmed that the relative risk was not increased with mean FA exposures below 1 ppm and peak exposures below 4 ppm. Hodgkin's lymphoma, not observed in the other studies reviewed and not considered FA dependent, was increased in the NCI cohort at a mean concentration ≥0.6 mg/m3 and at peak exposures ≥2.5 mg/m3; both levels are above the WHO guideline. Overall, the credibility of the WHO guideline has not been challenged by new studies.

Is it possible to use biomonitoring for the quantitative assessment of formaldehyde occupational exposure?

The European classification, labeling and packaging classified formaldehyde as human carcinogen Group 1B and mutagen 2, fostering the re-evaluation of the exposure risk in occupational settings. Although formaldehyde exposure is traditionally measured in air, many efforts were made to identify specific exposure biomarkers: urinary formaldehyde, formic acid and DNA damage indicators. Though used in combination, none of these seems satisfactory. The influence of the metabolism on exogenous formaldehyde levels, the exposure to other xenobiotics, the difference in genetic background and metabolism efficiency, misled the relationship between genotoxicity and exposure data. Nevertheless, the limitation of adverse effects to the local contact sites hampers biomonitoring. Here we discuss the feasibility of formaldehyde biomonitoring and the use of DNA, DNA-protein cross-links and protein adducts as potential biomarkers.

Comparison of hematological alterations and markers of B-cell activation in workers exposed to benzene, formaldehyde and trichloroethylene

Benzene, formaldehyde (FA) and trichloroethylene (TCE) are ubiquitous chemicals in workplaces and the general environment. Benzene is an established myeloid leukemogen and probable lymphomagen. FA is classified as a myeloid leukemogen but has not been associated with non-Hodgkin lymphoma (NHL), whereas TCE has been associated with NHL but not myeloid leukemia. Epidemiologic associations between FA and myeloid leukemia, and between benzene, TCE and NHL are, however, still debated. Previously, we showed that these chemicals are associated with hematotoxicity in cross-sectional studies of factory workers in China, which included extensive personal monitoring and biological sample collection. Here, we compare and contrast patterns of hematotoxicity, monosomy 7 in myeloid progenitor cells (MPCs), and B-cell activation biomarkers across these studies to further evaluate possible mechanisms of action and consistency of effects with observed hematologic cancer risks. Workers exposed to benzene or FA, but not TCE, showed declines in cell types derived from MPCs, including granulocytes and platelets. Alterations in lymphoid cell types, including B cells and CD4+ T cells, and B-cell activation markers were apparent in workers exposed to benzene or TCE. Given that alterations in myeloid and lymphoid cell types are associated with hematological malignancies, our data provide biologic insight into the epidemiological evidence linking benzene and FA exposure with myeloid leukemia risk, and TCE and benzene exposure with NHL risk.

Formaldehyde-induced toxicity in the nasal epithelia of workers of a plastic laminate plant

Formaldehyde is a ubiquitous volatile organic compound widely used for various industrial purposes. Formaldehyde was reclassified by the International Agency for Research on Cancer as a human carcinogen, based on sufficient evidence for a casual role for nasopharyngeal cancer. However, the mechanisms by which this compound causes nasopharyngeal cancer are not completely understood. Therefore, we have examined the formaldehyde-induced toxicity in the nasal epithelia of the workers of a plastic laminate plant in Bra, Cuneo, Piedmont region, North-Western Italy, hence in the target site for formaldehyde-related nasal carcinogenesis. We have conducted a cross-sectional study aimed at comparing the frequency of 3-(2-deoxy-β-d-erythro-pentafuranosyl)pyrimido[1,2-α]purin-10(3H)-one deoxyguanosine (M1dG) adducts, a biomarker of oxidative stress and lipid peroxidation, in 50 male exposed workers and 45 male controls using 32P-DNA post-labeling. The personal levels of formaldehyde exposure were analysed by gas-chromatography mass-spectrometry. The smoking status was estimated by measuring the concentrations of urinary cotinine by gas-chromatography mass-spectrometry. The air monitoring results showed that the exposure levels of formaldehyde were significantly greater for the plastic laminate plant workers, 211.4 ± 14.8 standard error (SE) μg m-3, than controls, 35.2 ± 3.4 (SE) μg m-3, P < 0.001. The levels of urinary cotinine were 1064 ± 118 ng ml-1 and 14.18 ± 2.5 ng ml-1 in smokers and non-smokers, respectively, P < 0.001. The M1dG adduct frequency per 108 normal nucleotides was significantly higher among the workers of the plastic laminate plant exposed to formaldehyde, 111.6 ± 14.3 (SE), compared to controls, 49.6 ± 3.4 (SE), P < 0.001. This significant association persisted also when personal dosimeters were used to measure the extent of indoor levels of formaldehyde exposure. No influences of smoking and age were observed across the study population. However, after categorization for occupational exposure, a significant effect was found in the controls, P = 0.018, where the levels of DNA damage were significantly correlated with the levels of urinary cotinine, regression coefficient (β) = 0.494 ± 0.000 (SE), P < 0.002. Our findings indicated that M1dG adducts constitute a potential mechanism of formaldehyde-induced toxicity. Persistent DNA damage contributes to the general decline of the physiological mechanisms designed to maintain cellular homeostasis.

Identification of Genes That Modulate Susceptibility to Formaldehyde and Imatinib by Functional Genomic Screening in Human Haploid KBM7 Cells

Though current functional genomic screening systems are useful for investigating human susceptibility to chemical toxicity, they have limitations. Well-established, high-throughput yeast mutant screens identify only evolutionarily conserved processes. RNA interference can be applied in human cells but is limited by incomplete gene knockout and off-target effects. Human haploid cell screening is advantageous as it requires knockdown of only a single copy of each gene. A human haploid cell mutant library (KBM7-Mu), derived from a chronic myeloid leukemia (CML) patient, was recently developed and has been used to identify genes that modulate sensitivity to infectious agents and pharmaceutical drugs. Here, we sought to improve the KBM7-Mu screening process to enable efficient screening of environmental chemicals. We developed a semi-solid medium based screening approach that cultures individual mutant colonies from chemically resistant cells, faster (by 2-3 weeks) and with less labor than the original liquid medium-based approach. As proof of principle, we identified genetic mutants that confer resistance to the carcinogen formaldehyde (FA, 12 genes, 18 hits) and the CML chemotherapeutic agent imatinib (6 genes, 13 hits). Validation experiments conducted on KBM7 mutants lacking each of the 18 genes confirmed resistance of 6 FA mutants (CTC1, FCRLA, GOT1, LPR5, M1AP, and MAP2K5) and 1 imatinib-resistant mutant (LYRM9). Despite the improvements to the method, it remains technically challenging to limit false positive findings. Nonetheless, our findings demonstrate the broad applicability of this optimized haploid approach to screen toxic chemicals to identify novel susceptibility genes and gain insight into potential mechanisms of toxicity.

Respiratory protection for firefighters--Evaluation of CBRN canisters for use during overhaul II: In mask analyte sampling with integrated dynamic breathing machine

According to the National Fire Protection Association there were 487,500 structural fires in the U.S. in 2013. After visible flames are extinguished firefighters begin the overhaul stage where remaining hot spots are identified and further extinguished. During overhaul, a significant amount of potentially hazardous chemicals can remain in the ambient environment. Previous research suggests that the use of air purifying respirators fitted with chemical, biological, radiological, and nuclear (CBRN) canisters may reduce occupational exposure. This study used large scale burns of representative structural materials to perform side-by-side, filtering, and service-life evaluations of commercially available CBRN filters using two head forms fitted with full-face respirators and a dynamic breathing machine. Three types of CBRN canisters and one non-CBRN cartridge were challenged in repetitive post-fire environments. Tests were conducted with two different breathing volumes and rates for two sampling durations (0-15 min and 0-60 min). Fifty-five different chemicals were selected for evaluation and results indicate that 10 of the 55 chemicals were present in the post-fire overhaul ambient environment. Acetaldehyde and formaldehyde were found to be the only two chemicals detected post filter but were effectively filtered to below ACGIH TLVs. Counter to our prior published work using continuous flow filter evaluation, this study indicates that, regardless of brand, CBRN filters were effective at reducing concentrations of post-fire ambient chemicals to below occupational exposure limits. However, caution should be applied when using CBRN filters as the ambient formaldehyde level in the current study was 8.9 times lower than during the previous work.

An Update on the Hazards and Risks of Forensic Anthropology, Part II: Field and Laboratory Considerations

This paper focuses on potential hazards and risks to forensic anthropologists while working in the field and laboratory in North America. Much has changed since Galloway and Snodgrass published their seminal article addressing these issues. The increased number of forensic practitioners combined with new information about potential hazards calls for an updated review of these pathogens and chemicals. Discussion of pathogen hazards (Brucella, Borrelia burgdorferi, Yersinia pestis, Clostridium tetani and West Nile virus) includes important history, exposure routes, environmental survivability, early symptoms, treatments with corresponding morbidity and mortality rates, and decontamination measures. Additionally, data pertaining to the use of formaldehyde in the laboratory environment have resulted in updated safety regulations, and these are highlighted. These data should inform field and laboratory protocols. The hazards of working directly with human remains are discussed in a companion article, "An Update on the Hazards and Risks of Forensic Anthropology, Part I: Human Remains."

Circulating immune/inflammation markers in Chinese workers occupationally exposed to formaldehyde

BACKGROUND

Formaldehyde has been classified as a human myeloid leukemogen. However, the mechanistic basis for this association is still debated.

OBJECTIVES

We aimed to evaluate whether circulating immune/inflammation markers were altered in workers occupationally exposed to formaldehyde.

METHODS

Using a multiplexed bead-based assay, we measured serum levels of 38 immune/inflammation markers in a cross-sectional study of 43 formaldehyde-exposed and 51 unexposed factory workers in Guangdong, China. Linear regression models adjusting for potential confounders were used to compare marker levels in exposed and unexposed workers.

RESULTS

We found significantly lower circulating levels of two markers among exposed factory workers compared with unexposed controls that remained significant after adjusting for potential confounders and multiple comparisons using a false discovery rate of 10%, including chemokine (C-X-C motif) ligand 11 (36.2 pg/ml in exposed versus 48.4 pg/ml in controls, P = 0.0008) and thymus and activation regulated chemokine (52.7 pg/ml in exposed versus 75.0 pg/ml in controls, P = 0.0028), suggesting immunosuppression among formaldehyde-exposed workers.

CONCLUSIONS

Our findings are consistent with recently emerging understanding that immunosuppression might be associated with myeloid diseases. These findings, if replicated in a larger study, may provide insights into the mechanisms by which formaldehyde promotes leukemogenesis.

Increased levels of chromosomal aberrations and DNA damage in a group of workers exposed to formaldehyde

Formaldehyde (FA) is a commonly used chemical in anatomy and pathology laboratories as a tissue preservative and fixative. Because of its sensitising properties, irritating effects and cancer implication, FA accounts probably for the most important chemical-exposure hazard concerning this professional group. Evidence for genotoxic effects and carcinogenic properties in humans is insufficient and conflicting, particularly in regard to the ability of inhaled FA to induce toxicity on other cells besides first contact tissues, such as buccal and nasal cells. To evaluate the effects of exposure to FA in human peripheral blood lymphocytes, a group of 84 anatomy pathology laboratory workers exposed occupationally to FA and 87 control subjects were tested for chromosomal aberrations (CAs) and DNA damage (comet assay). The level of exposure to FA in the workplace air was evaluated. The association between genotoxicity biomarkers and polymorphic genes of xenobiotic-metabolising and DNA repair enzymes were also assessed. The estimated mean level of FA exposure was 0.38±0.03 ppm. All cytogenetic endpoints assessed by CAs test and comet assay % tail DNA (%TDNA) were significantly higher in FA-exposed workers compared with controls. Regarding the effect of susceptibility biomarkers, results suggest that polymorphisms in CYP2E1 and GSTP1 metabolic genes, as well as, XRCC1 and PARP1 polymorphic genes involved in DNA repair pathways are associated with higher genetic damage in FA-exposed subjects. Data obtained in this study show a potential health risk situation of anatomy pathology laboratory workers exposed to FA (0.38 ppm). Implementation of security and hygiene measures may be crucial to decrease risk. The obtained information may also provide new important data to be used by health care programs and by governmental agencies responsible for occupational health and safety.

Respiratory protection for firefighters--evaluation of CBRN canisters for use during overhaul

In the United States, there are approximately 366,600 structural fires each year. After visible flames are extinguished, firefighters begin the overhaul stage of firefighting to smother remaining hot spots and initiate investigations. Typically during overhaul significant ambient concentrations of chemical contaminants remain. However, previous research suggests that the use of air purifying respirators (APR) fitted with chemical, biological, radiological, and nuclear (CBRN) canisters may reduce occupational respiratory exposures. This pilot study used large-scale prescribed burns of representative structural materials to perform simultaneous, side-by-side, filtering and service-life evaluations of commercially available CBRN filters. Three types of CBRN canisters and one cartridge were challenged in repetitive post live-fire overhaul exposure tests using a sampling manifold apparatus. At a flow rate of 80 L/min, nine tests were conducted in the breathing zone for three different exposure durations (0-15 min, 0-30 min, and 0-60 min). Fifty different chemicals were identified for evaluation and results indicate that 21 of the 50 chemicals tested were in the air of the overhaul environment. Respirable particles and formaldehyde were consistently present above the American Conference of Governmental Industrial Hygienists (ACGIH®) recommended exposure level (REL) and threshold limit ceiling value (TLVc), respectively. Each filter effectively reduced concentrations for respirable particulates below the maximum recommended level. Formaldehyde was reduced, but not consistently filtered below the TLVc. These results were consistent across all exposure durations. This study indicates that, regardless of brand, CBRN filters provide protection from the vast majority of particle and gas-phase contaminants. However, due to formaldehyde breakthrough, CBRN filters do not provide complete protection during firefighter overhaul.

Small molecule metabolite biomarker candidates in urine from mice exposed to formaldehyde

Formaldehyde (FA) is a ubiquitous compound used in a wide variety of industries, and is also a major indoor pollutant emitted from building materials, furniture, etc. Because FA is rapidly metabolized and endogenous to many materials, specific biomarkers for exposure have not been identified. In this study, we identified small metabolite biomarkers in urine that might be related FA exposure. Mice were allowed to inhale FA (0, 4, 8 mg/m³) 6 h per day for 7 consecutive days, and urine samples were collected on the 7th day of exposure. Liquid chromatography coupled with time of flight-mass spectrometry and principal component analysis (PCA) was applied to determine alterations of endogenous metabolites in urine. Additionally, immune toxicity studies were conducted to ensure that any resultant toxic effects could be attributed to inhalation of FA. The results showed a significant decrease in the relative rates of T lymphocyte production in the spleen and thymus of mice exposed to FA. Additionally, decreased superoxide dismutase activity and increased reactive oxygen species levels were found in the isolated spleen cells of exposed mice. A total of 12 small molecules were found to be altered in the urine, and PCA analysis showed that urine from the control and FA exposed groups could be distinguished from each other based on the altered molecules. Hippuric acid and cinnamoylglycine were identified in urine using exact mass and fragment ions. Our results suggest that the pattern of metabolites found in urine is significantly changed following FA inhalation, and hippuric acid and cinnamoylglycine might represent potential biomarker candidates for FA exposure.

Can consumption of raw vegetables decrease the count of sister chromatid exchange? Results from a cross-sectional study in Krakow, Poland

Background

Sister chromatid exchange (SCE) is a widely used sensitive cytogenetic biomarker of exposure to genotoxic and cancerogenic agents. Results of human monitoring studies and cytogenetic damage have revealed that biological effects of genotoxic exposures are influenced by confounding factors related to life-style. Vegetable and fruit consumption may play a role, but available results are not consistent. The purpose of the study was to investigate the effect of consumption of raw and cooked vegetables and fruits on SCE frequency.

Methods

A total of 62 participants included colorectal cancer (CRC) patients, hospital-based controls and healthy laboratory workers. SCE frequency was assessed in blood lymphocytes. Frequency of vegetable and fruit consumption was gathered by structured semi-quantitative food frequency questionnaire.

Results

SCE frequency was lowest among hospital-based controls (4.4 ± 1.1), a bit higher in CRC patients (4.5 ± 1.0) and highest among laboratory workers (7.4 ± 1.2) (p < 0.05). Multivariable linear regression showed a significant inverse effect (b = −0.20) of raw vegetable consumption, but not so for intake of cooked vegetables and fruits.

Conclusions

The results of the study have shown the beneficial effect of consumption of raw vegetables on disrupted replication of DNA measured by SCE frequency, implying protection against genotoxic agents. Further effort is required to verify the role of cooked vegetables and fruits.