Occupational exposure to formaldehyde and risk of lung cancer: A systematic review and meta-analysis.

BACKGROUND: Formaldehyde exposure is associated with nasopharyngeal cancer and leukemia. Previously-described links between formaldehyde exposure and lung cancer have been weak and inconsistent. We performed a systematic review and meta-analysis to evaluate quantitatively the association between formaldehyde exposure and lung cancer. METHODS: We searched for articles on occupational formaldehyde exposure and lung cancer in PubMed, EMBASE, Web of Science, and CINAHL databases. In total, 32 articles were selected and 31 studies were included in a meta-analysis. Subgroup analyses and quality assessments were also performed. RESULTS: The risk of lung cancer among workers exposed to formaldehyde was not significantly increased, with an overall pooled risk estimate of 1.04 (95% confidence interval [CI], 0.97-1.12). The pooled risk estimate of lung cancer was increased when higher exposure studies were considered (1.19; 95% CI, 0.96-1.46). More statistically robust results were obtained when high quality (1.13; 95% CI, 1.08-1.19) and recent (1.13; 95% CI, 1.07-1.19) studies were used in deriving pooled risk estimates. CONCLUSIONS: No significant increase in the risk of lung cancer was evident in the overall pooled risk estimate; even in higher formaldehyde exposure groups. Our findings do not provide strong evidence in favor of formaldehyde as a risk factor for lung cancer. However, since risk estimates were significantly increased for high-quality and recent studies, the possibility that exposure to formaldehyde can increase the risk of lung cancer might still be considered.

The impact of co-morbidities on a 6-year survival after methanol mass poisoning outbreak: possible role of metabolic formaldehyde.

Context: The influence of co-morbid conditions on the outcome of acute methanol poisoning in mass poisoning outbreaks is not known.Objective: The objective of this is to study the impact of burden of co-morbidities, complications, and methanol-induced brain lesions on hospital, follow-up, and total mortality.Methods: All patients hospitalized with methanol poisoning during a mass poisoning outbreak were followed in a prospective cohort study until death or final follow-up after 6 years. The age-adjusted Charlson co-morbidity index (ACCI) score was calculated for each patient. A multivariate Cox regression model was used to calculate the adjusted hazards ratio (HR) for death. The survival was modeled using the Kaplan-Meier method.Results: Of 108 patients (mean age with SD 50.9 ± 2.6 years), 24 (54.4 ± 5.9 years) died during hospitalization (mean survival with SD 8 ± 4 days) and 84 (49.9 ± 3.0 years; p = .159) were discharged, including 27 with methanol-induced brain lesions. Of the discharged patients, 15 (56.3 ± 6.8 years) died during the follow-up (mean survival 37 ± 11 months) and 69 (48.5 ± 3.3 years; p = .044) survived. The hospital mortality was 22%, the follow-up mortality was 18%; the total mortality was 36%. Cardiac/respiratory arrest, acute respiratory failure, multiorgan failure syndrome, and arterial hypotension increased the HR for hospital and total (but not follow-up) mortality after adjustment for age, sex, and arterial pH (all p < .05). All patients who died in the hospital had at least one complication. A higher ACCI score was associated with greater total mortality (HR 1.22; 1.00-1.48 95% CI; p = .046). Of those who died, 35 (90%) had a moderate-to-high ACCI. The Kaplan-Meier curve demonstrated that patients with a high ACCI had greater follow-up mortality compared to ones with low (p = .027) or moderate (p = .020) scores. For the patients who died during follow-up, cancers of different localizations were responsible for 7/15 (47%) of the deaths.Conclusions: The character and number of complications affected hospital but not follow-up mortality, while the burden of co-morbidities affected follow-up mortality. Methanol-induced brain lesions did not affect follow-up mortality. Relatively high cancer mortality rate may be associated with acute exposure to metabolic formaldehyde produced by methanol oxidation.

Occupational exposure to formaldehyde and risk of non hodgkin lymphoma: a meta-analysis.

BACKGROUND: Formaldehyde, a widely used chemical, is considered a human carcinogen. We report the results of a meta-analyses of studies on the relationship between occupational exposure to formaldehyde and risk of non-Hodgkin lymphoma (NHL). METHODS: We performed a systematic review and meta-analysis according to international guidelines and we identified 12 reports of occupational populations exposed to formaldehyde. We evaluated inter-study heterogeneity and we applied a random effects model. We conducted a cumulative meta-analysis and a meta-analysis according to estimated average exposure of each study population. RESULTS: The meta-analysis resulted in a summary relative risk (RR) for NHL of 0.93 (95% confidence interval 0.83-1.04). The cumulative meta-analysis suggests that higher RRs were detected in studies published before 1986, while studies available after 1986 did not show an association. No differences were found between different levels of occupational exposure. Conclusions Notwithstanding some limitations, the results of this meta-analysis do not support the hypothesis of an association between occupational exposure to formaldehyde and risk of NHL.

Risco do uso do formol na estética capilar riesgo del uso del formol en la estética capilar / Risk of the use of formol in hair aesthetics

Resumo:Buscou-se determinar a apresentação nos meios de comunicação dos riscos do uso de formol na estética capilar por meio de notícias de lesões corporais e morte; reconhecer a percepção de profissionais cabeleireiros da cidade de Petrópolis- RJ, Brasil, sobre esses riscos e evidenciar a presença da substância em cosméticos. Para tanto, analisaram-se matérias jornalísticas, divulgadas após 2007, relacionadas a casos reais de exposição ao formol. Realizou-se também inquérito com 12 profissionais cabeleireiros, buscando determinar o conhecimento sobre a presença ou adição de formol em produtos alisantes e dos riscos à saúde ocasionados pelo uso da substância, além da relação que faziam entre o formol e ocorrências clínicas neles próprios ou em seus clientes. Na ocasião, foram solicitadas amostras de produtos para a determinação qualitativa do formol. Das 12 amostras analisadas, 9 (75%) apresentaram teor de formol superior a 0,01%. Reconheceu-se que apesar da regulamentação e de algum conhecimento dos cabeleireiros sobre os riscos, o uso do formol em alisantes continua. Foi possível detectar a substância nos produtos examinados. Entretanto, diminuíram as reportagens sobre casos de intoxicação aguda por formol na estética capilar.

Resumen:Se buscó determinar la presentación en los medios de comunicación de los riesgos del uso de formol en la estética capilar por medio de noticias de lesiones corporales y muerte; Reconocer la percepción de profesionales peluqueros de la ciudad de Petrópolis-RJ, Brasil, sobre esos riesgos y evidenciar la presencia de la sustancia en cosméticos. Para ello, se analizaron materias periodísticas, divulgadas después de 2007, relacionadas a casos reales de exposición al formol. Se realizaron también encuestas con 12 profesionales peluqueros, buscando determinar el conocimiento sobre la presencia o adición de formol en productos alisantes y de los riesgos a la salud ocasionados por el uso de la sustancia, además de la relación que hacían entre el formol y ocurrencias clínicas en ellos mismos o en Sus clientes. En la ocasión, se solicitaron muestras de productos para la determinación cualitativa del formol. De las 12 muestras analizadas, 9 (75%) presentaron un contenido de formol superior al 0,01%. Se reconoció que a pesar de la reglamentación y de algún conocimiento de los peluqueros sobre los riesgos, el uso del formol en alisantes continúa. Es posible detectar la sustancia en los productos examinados. Sin embargo, disminuyeron los reportajes sobre casos de intoxicación aguda por formol en la estética capilar.

Abstract:It was sought to determine the media presentation of risks formaldehyde used in hair aesthetics, by the news about personal injury and death; recognize the perception of hairdressing professionals in Petrópolis-RJ, Brazil, on these risks and highlight the presence of the substance in cosmetics. Therefore, it was analyzed newspaper articles, published after 2007, related to real cases of exposure to formaldehyde. It was also conducted survey of 12 professional hairdressers and to determine the knowledge of the presence or addition of formaldehyde in hair straighteners products and the health risks caused by the use of the substance and the relation that were between formaldehyde and clinical events in themselves or its customers. At the time, product samples were requested for the qualitative determination of formaldehyde. In the 12 samples, 9 (75%) had concentration greater than 0.01% formaldehyde. It was recognized that despite the regulation and some knowledge of hairdressers about the risks, the use of formaldehyde in hair straighteners continues. It was possible to detect the substance in the products examined.However, it were decreased the reports of cases of acute formaldehyde toxication in hair aesthetics.

The Effects of Formaldehyde on Cytochrome P450 Isoform Activity in Rats.

Formaldehyde (FA) is an occupational and indoor pollutant. Long-term exposure to FA can irritate the respiratory mucosa, with potential carcinogenic effects on the airways. The effects of acute FA poisoning on the activities of CYP450 isoforms CYP1A2, CYP2C11, CYP2E1, and CYP3A2 were assessed by determining changes in the pharmacokinetic parameters of the probe drugs phenacetin, tolbutamide, chlorzoxazone, and testosterone, respectively. Rats were randomly divided into three groups: control, low FA dose (exposure to 110 ppm for 2 h for 3 days), and high FA dose (exposure to 220 ppm for 2 h for 3 days). A mixture of the four probe drugs was injected into rats and blood samples were taken at a series of time points. Plasma concentrations of the probe drugs were measured by HPLC. The pharmacokinetic parameters t1/2, AUC(0-t), and Cmax of tolbutamide, chlorzoxazone, and testosterone increased significantly in the high dose versus control group (P < 0.05), whereas the CL of chlorzoxazone and testosterone decreased significantly (P < 0.05). However, t1/2, AUC(0-t), and Cmax of phenacetin decreased significantly (P < 0.05), whereas the CL of phenacetin increased significantly (P < 0.05) compared to controls. Thus, acute FA poisoning suppressed the activities of CYP2C11, CYP2E1, and CYP3A2 and induced the activity of CYP1A2 in rats. And the change of CYP450 activity caused by acute FA poisoning may be associated with FA potential carcinogenic effects on the airways.

Accidental intraoral injection of formalin during extraction: case report.

Transparent, clear solutions such as hydrogen peroxide, alcohol, sodium hypochlorite, formaldehyde, and local anaesthetics are widely used in dentistry, so the tissues are liable to accidental injury. Formalin, a 37%-40% solution of formaldehyde, is extensively used in 10% solution as a tissue preservative, but it has toxic effects on systems such as the gastrointestinal tract, respiratory tract, skin, and mucosa. However, we know of few reports of cases of inadvertent injection of alcohol and formalin directly into the human body. In this case report we describe the early and delayed clinical effects of accidental intraoral injection of formalin, the subsequent symptoms and management, and some prudent points that should be learnt to avoid such incidents in the future.

Homicidal acute formalin poisoning in an infant from a rural sericulture family presenting with multisystem failure.

Acute poisoning of formalin is rare because of its strong irritating effect and alarming odor. Although few cases of acute poisoning in adults have been reported in literature, to our knowledge, this is the first case report of formalin poisoning in an infant presenting with multisystem failure. Despite proper supportive treatment in the absence of antidote, the infant died within 13 hours after deliberate poisoning.

Formaldehyde carcinogenicity research: 30 years and counting for mode of action, epidemiology, and cancer risk assessment.

Formaldehyde is a widely used high production chemical that is also released as a byproduct of combustion, off-gassing of various building products, and as a fixative for pathologists and embalmers. What is not often realized is that formaldehyde is also produced as a normal physiologic chemical in all living cells. In 1980, chronic inhalation of high concentrations of formaldehyde was shown to be carcinogenic, inducing a high incidence of nasal squamous cell carcinomas in rats. Some epidemiologic studies have also found increased numbers of nasopharyngeal carcinoma and leukemia in humans exposed to formaldehyde that resulted in formaldehyde being considered a Known Human Carcinogen. This article reviews the data for rodent and human carcinogenicity, early Mode of Action studies, more recent molecular studies of both endogenous and exogenous DNA adducts, and epigenetic studies. It goes on to demonstrate the power of these research studies to provide critical data to improve our ability to develop science-based cancer risk assessments, instead of default approaches. The complexity of constant physiologic exposure to a known carcinogen requires that new ways of thinking be incorporated into determinations of cancer risk assessment for formaldehyde, other endogenous carcinogens, and the role of background endogenous DNA damage and mutagenesis.

Exposure to formaldehyde and its potential human health hazards.

A widely used chemical, formaldehyde is normally present in both indoor and outdoor air. The rapid growth of formaldehyde-related industries in the past two decades reflects the result of its increased use in building materials and other commercial sectors. Consequently, formaldehyde is encountered almost every day from large segments of society due to its various sources. Many governments and agencies around the world have thus issued a series of standards to regulate its exposure in homes, office buildings, workshops, public places, and food. In light of the deleterious properties of formaldehyde, this article provides an overview of its market, regulation standards, and human health effects.

[Isocyanates and formaldehyde--low molecular weight xenobiotics]. / Izocyjaniany i formaldehyd--maloczasteczkowe ksenobiotyki.

Isocyanates and formaldehyde are a low molecular weight environmental xenobiotics. Acute poisonings are relatively rare, chronic exposure not enough recognized. A source, mechanism of toxicity and ability of those low molecular weight compounds to stimulation of different types of immune response are presented in the study.

Assessment of genotoxic effects and changes in gene expression in humans exposed to formaldehyde by inhalation under controlled conditions.

Forty-one volunteers (male non-smokers) were exposed to formaldehyde (FA) vapours for 4 h/day over a period of five working days under strictly controlled conditions. For each exposure day, different exposure concentrations were used in a random order ranging from 0 up to 0.7 p.p.m. At concentrations of 0.3 and 0.4 p.p.m., four peaks of 0.6 or 0.8 p.p.m. for 15 min each were applied. During exposure, subjects had to perform bicycle exercises (∼80 W) four times for 15 min. Blood samples, exfoliated nasal mucosa cells and nasal biopsies were taken before the first and after the last exposure. Nasal epithelial cells were additionally sampled 1, 2 and 3 weeks after the end of the exposure period. The alkaline comet assay, the sister chromatid exchange test and the cytokinesis-block micronucleus test were performed with blood samples. The micronucleus test was also performed with exfoliated nasal mucosa cells. The expression (mRNA level) of the glutathione (GSH)-dependent formaldehyde dehydrogenase (FDH, identical to alcohol dehydrogenase 5; ADH5; EC 1.2.1.46) was measured in blood samples by quantitative real-time reverse transcription-polymerase chain reaction with TaqMan probes. DNA microarray analyses using a full-genome human microarray were performed on blood samples and nasal biopsies of selected subgroups with the highest FA exposure at different days. Under the experimental conditions of this study, inhalation of FA did not lead to genotoxic effects in peripheral blood cells and nasal mucosa and had no effect on the expression of the FDH gene. Inhalation of FA did also not cause alterations in the expression of genes in a microarray analysis with nasal biopsies and peripheral blood cells.

A case of death after ingestion of an agrochemical spreading agent.

An agrochemical spreading agent was found near the slightly decomposed corpse of a deceased female. The appearance of the stomach contents suggested that ingestion of a surfactant had occurred before death. The spreading agent was found to contain nonionic nonylphenol ethoxylates (NPEO(n)) and anionic sulfonated naphthalene-formaldehyde condensates (SNFC(n)). A solid phase extraction cartridge containing a mixed reversed phase-weak anion exchange sorbent (Oasis WAX, Waters) was used to successfully extract both NPEO(n) and SNFC(n) from the blood. The cartridge was preconditioned with methanol and acetic acid (AcOH). After the dilute blood sample was applied to the cartridge, it was washed with AcOH, and then NPEO(n) and SNFC(n) were eluted with methanol/dichloromethane (7:3, v/v) and 5% NH(3)/80% methanol, respectively. The concentrations of NPEO(n=2-9) and SNFC(n=0) in the blood sample were 7.7µg/mL and 1.8mg/mL, respectively. It is possible that postmortem changes increased the concentration of SNFC(n=0) monomer by breaking down the polymer. However, the behavior of these compounds in the human body is unclear and further case studies are needed to investigate this result.

Formalin: nephrotoxic teratogen?

Formaldehyde is an extensively used chemical; its ill effects have been of concern. Its nephrotoxic effects in laboratory animals and carcinogenic effects on humans are well established. We report of a pregnant woman with a normal ongoing pregnancy with a morphologically normal fetus. She was exposed to high doses of formaldehyde through inhalational route in the second trimester. Six weeks later she was found to have severe oligohydramnios with dysplastic fetal kidneys and fetal ascites. The various known causes for this problem reported in the literature are discussed. Based on the discussion the author has drawn a conclusion that the fate of the fetus reported can be attributed to transplacental nephrotoxic effect of formaldehyde. Previously two cases of malformations have been reported but this appears to be the first case of transplacental nephrotoxicty of formaldehyde.

[Advancement of methanol poisoning mechanism research].

The methanol poisoning by oral intake or skin contact occurs occasionally, which may have serious consequences including blindness and/or death. Methanol and its metabolites, formaldehyde and formic acid, are associated with metabolic acidosis, visual dysfunction and neurological symptoms. At present, the mechanism of methanol poisoning primarily focuses on the cell hypoxia, the alteration of structure and biological activity induced by free radical and lactic acid. Meanwhile, methanol poisoning causes changes in the balance between the production of free radicals and antioxidant capacity and in the proteases-protease inhibitors system, which lead to a series of disturbances.