A review and meta-analysis of formaldehyde exposure and pancreatic cancer

The dark side of being a pathologist: Unravelling the health hazards

Background

Pathologists are indispensable to the practice of medicine. Awareness of health hazards among pathologists is a crucial aspect of today's time. Numerous occupational health risks are prevalent which are mostly ignored; for example, the association of microscope use for prolonged durations leading to the development of chronic pain syndromes has been acknowledged for nearly three decades, yet most pathologists are unaware about this hazard until after it transforms into a chronic health issue. The purpose of this study is to learn its prevalence in working pathologists, make them aware of the risks, discuss and encourage them to proactively integrate strategies which are preventive in nature into their daily routine lives.

Objective

The aim of the study was to analyze the level of risk, knowledge, awareness and biosafety measures taken by the pathologists in their routine daily work life.

Materials and Methods

The study was conducted in a developing country, Northern India, using a standard online 50-item questionnaire enquiring about routine practices. 450 participants were enrolled consisting of 360 pathologists and 90 residents of pathology.

Results

Among the 450 enrolled study participants, 84.8% complained of musculoskeletal disorders (MSD), with the neck being the commonest location of pain. Furthermore, 74.8% reported visual refractive errors, among which myopia took the highest place. Work injuries were reported in 60% of participants. Intolerance reactions to chemicals especially formaldehyde was observed in 63.1%. Depression and burnout were reported in 42%.

Conclusions

Although knowledge seems to be near adequate, there is a lack of implementation and a noticeable risk of health hazards namely musculoskeletal problems, injuries, visual disorders, and ergonomic issues in routine daily activities of pathologists.

A review of plants formaldehyde metabolism: Implications for hazardous emissions and phytoremediation

The wide use of hazardous formaldehyde (CH₂O) in disinfections, adhesives and wood-based furniture leads to undesirable emissions to indoor environments. This is highly problematic as formaldehyde is a highly hazardous and toxic compound present in both liquid and gaseous form. The majority of gaseous and atmospheric formaldehyde derive from microbial and plant decomposition. However, plants also reversibly absorb formaldehyde released from for example indoor structural materials in such as furniture, thus offering beneficial phytoremediation properties. Here we provide the first comprehensive review of plant formaldehyde metabolism, physiology and remediation focusing on release and absorption including species-specific differences for maintaining indoor environmental air quality standards. Phytoremediation depends on rhizosphere, temperature, humidity and season and future indoor formaldehyde remediation therefore need to take these biological factors into account including the balance between emission and phytoremediation. This would pave the road for remediation of formaldehyde air pollution and improve planetary health through several of the UN Sustainable Development Goals.

New insights into the genetic contribution of ALDH2 rs671 in pancreatic carcinogenesis: evaluation by mediation analysis

A functional variant on ALDH2 rs671 (G>A) confers a protective effect against alcohol‐induced carcinogenesis through an indirect pathway mediated by decreased alcohol consumption. Conversely, this variant also contributes to the accumulation of carcinogenic agents, resulting in a direct carcinogenic effect. This study aimed to separately quantify these two opposing effects of the rs671 A allele on pancreatic cancer risk and explore the impact of the rs671 A allele and alcohol consumption on pancreatic carcinogenesis. We included 426 cases and 1456 age‐ and sex‐matched controls. Odds ratio (OR) and 95% confidence interval (CI) for alcohol consumption were estimated using a conditional logistic regression model. By defining rs671 A allele and alcohol consumption as exposure and mediator, respectively, we used mediation analysis to decompose the total‐effect OR of the rs671 A allele into direct‐ and indirect‐effect ORs. Alcohol consumption (10 g/d) was associated with pancreatic cancer risk (OR, 1.05; 95% CI, 1.01‐1.10), but tests for interaction between the rs671 A allele and alcohol consumption were nonsignificant, indicating that the effect of alcohol consumption did not vary by genotype. Mediation analysis showed that the nonsignificant total effect (OR, 1.15; 95% CI, 0.92‐1.44) can be decomposed into the carcinogenic direct (OR, 1.34; 95% CI, 1.04‐1.72) and protective indirect effect (OR, 0.86; 95% CI, 0.77‐0.95). This study supports the association between alcohol consumption and pancreatic cancer risk and indicates the potential contribution of the rs671 A allele to pancreatic carcinogenesis through impaired metabolism of known or unknown ALDH2 substrates.

The Carcinogenic Effects of Formaldehyde Occupational Exposure: A Systematic Review

BACKGROUND

Formaldehyde, classified as a carcinogen in 2004, as of today is widely used in many work activities. From its classification, further studies were performed to evaluate its carcinogenicity. The aim of the systematic review is to update the evidence on occupational exposure to formaldehyde and cancer onset.

METHODS

The review, in accordance with the PRISMA statement, includes articles in English reporting original results of studies conducted on workers exposed to formaldehyde, considering all types of cancer, published from 1 January 2000 to 30 July 2021 and selected from the Pubmed and Scopus databases. The studies' quality was assessed by the Newcastle-Ottawa Scale.

RESULTS

A total of 21 articles were included, conducted in different European, American, and Asian countries. The most investigated occupational areas are those characterized by a deliberate use of formaldehyde. Some studies evaluated all types of cancer, whereas others focused on specific sites such as thyroid and respiratory, lymphohematopoietic, or central nervous systems. The results showed weak associations with lung cancer, nasopharyngeal cancer, leukemia, and non-Hodgkin's lymphoma.

CONCLUSIONS

The results demonstrate the need for further original studies carried out on representative samples of workers exposed to measured levels of FA. These studies should be designed to reduce the bias due to co-exposure to other carcinogens.

Effect of Formaldehyde in Selective Catalytic Reduction of NOx by Ammonia (NH3-SCR) on a Commercial V2O5-WO3/TiO2 Catalyst under Model Conditions

The impact of formaldehyde (HCHO, formed in vehicle exhaust gases by incomplete combustion of fuel) on the performance of a commercial V₂O₅-WO₃/TiO₂ catalyst in NH₃-SCR of NO_x under dry conditions has been analyzed in detail by catalytic tests, in situ FTIR and transient studies using temporal analysis of products (TAP). HCHO reacts preferentially with NH₃ to a formamide (HCONH₂) surface intermediate. This deprives NH₃ partly from its desired role as a reducing agent in the SCR and diminishes NO conversion and N₂ selectivity. Between 250 and 400 °C, HCONH₂ decomposes by dehydration (major pathway) and decarbonylation (minor pathway) to liberate toxic HCN and CO, respectively. HCN was proven to be oxidized by lattice oxygen of the catalyst to CO₂ and NO, which enters the NH₃-SCR reaction.

Toenail concentrations of trace elements and occupational history in pancreatic cancer

BACKGROUND

Some occupations potentially entailing exposure to cadmium, arsenic, lead, selenium, nickel, and chromium have been associated with an increased risk of exocrine pancreatic cancer (EPC), but no studies have assessed whether body concentrations of such compounds differed among subjects occupationally exposed and unexposed. No studies which found that exposure to such metals increased the risk of EPC assessed whether past occupations were the source of exposure.

OBJECTIVE

The aim was to analyse the relationship between toenail concentrations of trace elements and occupational history in EPC patients.

METHODS

The study included 114 EPC cases personally interviewed on occupational history and lifestyle factors. Occupations were coded according to the International Standard Classification of Occupations 1988. Selected occupational exposures were assessed by two industrial hygienists and with the Finnish job-exposure matrix (Finjem). Concentrations of 12 trace elements were determined in toenail samples by inductively coupled plasma mass spectrometry. Adjusted geometric means (aGMs) and 95% confidence intervals (95% CI) were calculated.

RESULTS

Patients occupationally exposed to aromatic hydrocarbon solvents (AHs) had higher concentrations of cadmium, manganese, lead, iron and vanadium. The aGM of cadmium concentrations for cases exposed to any pesticide was 0.056 μg/g [95% CI: 0.029-0.108], and, for unexposed cases, 0.023 μg/g [0.017-0.031]. Patients occupationally exposed to pesticides had higher concentrations of cadmium and manganese. Higher concentrations of vanadium, lead and arsenic were related to exposure to formaldehyde. Vanadium and lead were also associated with exposure to chlorinated hydrocarbon solvents, and arsenic was related to exposure to polycyclic aromatic hydrocarbons (PAHs).

CONCLUSIONS

Patients occupationally exposed to AHs, pesticides, chlorinated hydrocarbon solvents, formaldehyde, volatile sulphur compounds and PAHs had higher concentrations of several metals. These elements may account for some of the occupational risks previously reported for pancreatic cancer.

Simultaneous presentation of pancreatic cancer in a genetically unrelated couple

Patients with pancreatic cancer tend to have a poor prognosis despite aggressive treatment, and their 5-year overall survival rate remains dismal. Several risk factors could potentially trigger the development of pancreatic cancer but many of them identified so far have been only weakly linked. Occurrence of pancreatic cancer in a husband and wife around the same time in the same household even when exposed to similar environmental factors is rare. Although familial pancreatic cancer is a known entity, pancreatic cancer in genetically unrelated married couples has not been studied. Here we present such a scenario involving one couple. In this case report, we discuss the chronological events leading to pancreatic cancer in a genetically unrelated married couple and the risk factors that may have led to cancer, in addition to exploring the possible links.

Toxic effects of formaldehyde on the urinary system

Formaldehyde is a chemical substance with a pungent odor that is highly soluble in water and occurs naturally in organisms. Formaldehyde, when taken into organisms, is metabolized into formic acid in the liver and erythrocytes and is then excreted, either with the urine and feces or via the respiratory system. Form-aldehyde is widely used in the industrial and medical fields, and employees in these sectors are frequently exposed to it. Anatomists and medical students are affected by formaldehyde gas during dissection lessons. Because full protection from formaldehyde is impossible for employees in industrial plants using this chemical and for workers in laboratory conditions, several measures can be implemented to prevent and/or reduce the toxic effects of formaldehyde. In this review, we aimed to identify the toxic effects of formaldehyde on the urinary system.

Risk factors for pancreatic cancer: a summary review of meta-analytical studies

BACKGROUND

The aetiology of pancreatic cancer (PC) has been extensively studied and is the subject of numerous meta-analyses and pooled analyses. We have summarized results from these pooled and meta-analytical studies to estimate the fraction of PCs attributable to each of the identified risk factors.

METHODS

Using a comprehensive strategy, we retrieved 117 meta-analytical or pooled reports dealing with the association between specific risk factors and PC risk. We combined estimates of relative risk and estimates of exposure to calculate the fraction of PCs caused or prevented by a particular exposure.

RESULTS

Tobacco smoking ('strong' evidence) and Helicobacter pylori infection ('moderate' evidence) are the major risk factors associated with PC, with respective estimated population attributable fractions of 11-32% and 4-25%. The major protective factors are history of allergy ('strong' evidence) and increasing fruit or folate intake ('moderate' evidence), with respective population preventable fractions of 3-7% and 0-12%.

CONCLUSIONS

We summarized results of 117 meta-analytical or pooled data reports dealing with 37 aetiological exposures, to obtain robust information about the suspected causes of PC. By combining these estimates with their prevalences in the population, we calculated population attributable or population preventable fractions. About two-thirds of the major risk factors associated with PC are potentially modifiable, affording a unique opportunity for preventing one of our deadliest cancers.

Amended Safety Assessment of Formaldehyde and Methylene Glycol as Used in Cosmetics

Formaldehyde and methylene glycol may be used safely in cosmetics if established limits are not exceeded and are safe for use in nail hardeners in the present practices of use and concentration, which include instructions to avoid skin contact. In hair-smoothing products, however, in the present practices of use and concentration, formaldehyde and methylene glycol are unsafe. Methylene glycol is continuously converted to formaldehyde, and vice versa, even at equilibrium, which can be easily shifted by heating, drying, and other conditions to increase the amount of formaldehyde. This rapid, reversible formaldehyde/methylene glycol equilibrium is distinguished from the slow, irreversible release of formaldehyde resulting from the so-called formaldehyde releaser preservatives, which are not addressed in this safety assessment (formaldehyde releasers may continue to be safely used in cosmetics at the levels established in their individual Cosmetic Ingredient Review safety assessments).

Occupational health risks of pathologists--results from a nationwide online questionnaire in Switzerland

BACKGROUND

Pathologists are highly trained medical professionals who play an essential part in the diagnosis and therapy planning of malignancies and inflammatory diseases. Their work is associated with potential health hazards including injuries involving infectious human tissue, chemicals which are assumed to be carcinogenic or long periods of microscope and computer work. This study aimed to provide the first comprehensive assessment of the health situation of pathologists in Switzerland.

METHODS

Pathologists in Switzerland were contacted via the Swiss Society of Pathologists and asked to answer an ethically approved, online anonymous questionnaire comprising 48 questions on occupational health problems, workplace characteristics and health behaviour.

RESULTS

163 pathologists participated in the study. Forty percent of pathologists reported musculoskeletal problems in the previous month. The overall prevalence was 76%. Almost 90% of pathologists had visual refraction errors, mainly myopia. 83% of pathologists had experienced occupational injuries, mostly cutting injuries, in their professional career; more than one fifth of participants reported cutting injuries in the last year. However, long lasting injuries and infectious diseases were rare. Depression and burnout affected every eighth pathologist. The prevalence of smoking was substantially below that of the general Swiss population.

CONCLUSIONS

The results of this study suggest that more care should be taken in technical and personal protective measures, ergonomic workplace optimisation and reduction of work overload and work inefficiencies. Despite the described health risks, Swiss pathologists were optimistic about their future and their working situation. The high rate of ametropia and psychological problems warrants further study.

Cancer effects of formaldehyde: a proposal for an indoor air guideline value

Formaldehyde is a ubiquitous indoor air pollutant that is classified as "Carcinogenic to humans (Group 1)" (IARC, Formaldehyde, 2-butoxyethanol and 1-tert-butoxypropanol-2-ol. IARC monographs on the evaluation of carcinogenic risks to humans, vol 88. World Health Organization, Lyon, pp 39-325, 2006). For nasal cancer in rats, the exposure-response relationship is highly non-linear, supporting a no-observed-adverse-effect level (NOAEL) that allows setting a guideline value. Epidemiological studies reported no increased incidence of nasopharyngeal cancer in humans below a mean level of 1 ppm and peak levels below 4 ppm, consistent with results from rat studies. Rat studies indicate that cytotoxicity-induced cell proliferation (NOAEL at 1 ppm) is a key mechanism in development of nasal cancer. However, the linear unit risk approach that is based on conservative ("worst-case") considerations is also used for risk characterization of formaldehyde exposures. Lymphohematopoietic malignancies are not observed consistently in animal studies and if caused by formaldehyde in humans, they are high-dose phenomenons with non-linear exposure-response relationships. Apparently, these diseases are not reported in epidemiological studies at peak exposures below 2 ppm and average exposures below 0.5 ppm. At the similar airborne exposure levels in rodents, the nasal cancer effect is much more prominent than lymphohematopoietic malignancies. Thus, prevention of nasal cancer is considered to prevent lymphohematopoietic malignancies. Departing from the rat studies, the guideline value of the WHO (Air quality guidelines for Europe, 2nd edn. World Health Organization, Regional Office for Europe, Copenhagen, pp 87-91, 2000), 0.08 ppm (0.1 mg m(-3)) formaldehyde, is considered preventive of carcinogenic effects in compliance with epidemiological findings.

[Risk factors and early diagnosis of pancreatic cancer]

Pancreatic cancer (PC) is usually incurable. Identifying people at risk for developing PC may improve the prognosis of this entity. The main risk factors for PC are Peutz-Jeghers syndrome, hereditary pancreatitis and a history family of PC. Other factors, such as advanced age and smoking, should also be taken into account. PC screening is only useful in very high risk individuals. Tools that allow tumors to be identified in the early stages are required in order to apply appropriate curative treatments. In this scenario, only endoscopic ultrasound with cytological analysis of suspicious pancreatic lesions has proved to be useful.

Genotoxic damage in pathology anatomy laboratory workers exposed to formaldehyde

Formaldehyde (FA) is a chemical traditionally used in pathology and anatomy laboratories as a tissue preservative. Several epidemiological studies of occupational exposure to FA have indicated an increased risk of nasopharyngeal cancers in industrial workers, embalmers and pathology anatomists. There is also a clear evidence of nasal squamous cell carcinomas from inhalation studies in the rat. The postulated mode of action for nasal tumours in rats was considered biologically plausible and considered likely to be relevant to humans. Based on the available data IARC, the International Agency for Research on Cancer, has recently classified FA as a human carcinogen. Although the in vitro genotoxic as well as the in vivo carcinogenic potentials of FA are well documented in mammalian cells and in rodents, evidence for genotoxic effects and carcinogenic properties in humans is insufficient and conflicting thus remains to be more documented. To evaluate the genetic effects of long-term occupational exposure to FA a group of 30 Pathological Anatomy laboratory workers was tested for a variety of biological endpoints, cytogenetic tests (micronuclei, MN; sister chromatid exchange, SCE) and comet assay. The level of exposure to FA was evaluated near the breathing zone of workers, time weighted average of exposure was calculated for each subject. The association between the biomarkers and polymorphic genes of xenobiotic metabolising and DNA repair enzymes was also assessed. The mean level of exposure was 0.44+/-0.08ppm (0.04-1.58ppm). MN frequency was significantly higher (p=0.003) in the exposed subjects (5.47+/-0.76) when compared with controls (3.27+/-0.69). SCE mean value was significantly higher (p<0.05) among the exposed group (6.13+/-0.29) compared with control group (4.49+/-0.16). Comet assay data showed a significant increase (p<0.05) of TL in FA-exposed workers (60.00+/-2.31) with respect to the control group (41.85+/-1.97). A positive correlation was found between FA exposure levels and MN frequency (r=0.384, p=0.001) and TL (r=0.333, p=0.005). Regarding the genetic polymorphisms studied, no significant effect was found on the genotoxic endpoints. The results of the present biomonitoring study emphasize the need to develop safety programs.

Pancreatic cancer: a review of the evidence on causation

Pancreatic cancer kills more than 250,000 people each year worldwide and has a poor prognosis. The aim of this article is to critically review the epidemiologic evidence for exposures that may either increase or decrease the risk. A Medline search was performed for epidemiologic studies and reviews published up to April 2007. Consistent evidence of a positive association was found for family history and cigarette smoking. Many studies documented a positive association with diabetes mellitus and chronic pancreatitis, although the etiologic mechanisms are unclear. Other associations were detected, but the results were either inconsistent or from few studies. These included positive associations with red meat, sugar, fat, body mass index, gallstones, and Helicobacter pylori, and protective effects of increasing parity, dietary folate, aspirin, and statins. There was no evidence linking alcohol or coffee consumption with an increased risk of pancreatic cancer. The associations with many exposures need to be clarified from further epidemiologic work in which there is both precise measurement of risk factors, adjustment for potential confounders, and, for dietary studies, information recorded on the method of food preparation and pattern of consumption. Such work is important to reduce the incidence of this fatal disease.

Inhalation exposure to formaldehyde and toluene in the same occupational and consumer setting

Formaldehyde, a natural component of all mammalian cells, is metabolized to carbon dioxide. It is a colorless gas used as a preservative and a reactant in chemical processes in a wide variety of commercial and consumer products. Toluene is an organic solvent also used in a wide variety of commercial and consumer products. There is a growing concern that chemical exposure from consumer products including cosmetics adds to the overall toxic exposure bioburden. This study was designed to quantify the actual amount of formaldehyde and toluene exposure to professional nail technicians and their customers during the application of cosmetic nail products containing either formaldehyde or toluene. Formaldehyde concentrations were measured on workers and consumers using treated silica gel absorption tubes. Formaldehyde concentrations varied between 0.0012 and 0.0038 ppm. The results of this study clearly demonstrate that neither workers nor consumers are at any additional risk from exposure to formaldehyde or toluene in cosmetic nail products beyond daily exposure from commercial products in a work setting and in the home.

Update on pancreatic cancer and alcohol-associated risk

Ductal adenocarcinoma of the pancreas is characterized by extremely aggressive behavior, with an overall 5-year survival of <4%. Because conventional and specifically tailored therapeutic regimens have little impact on patient survival, epidemiological and molecular research aims at identifying and reducing risk factors. Cigarette smoking, obesity, diabetes mellitus, and chronic pancreatitis are amenable to medical prevention or therapy. Heavy alcohol consumption is an inconsistent single risk factor for pancreatic cancer but may promote carcinogenesis by increasing the risk of diabetes mellitus or chronic pancreatitis. For various agents, the key carcinogenic effect is probably an inflammatory response in the pancreatic tissue. On the molecular level, mutations of oncogenes and tumor suppressor genes, as well as various epigenetic alterations, such as overexpression of growth factors and their receptors, are important in tumorigenesis. Complete and safe surgical resection, together with adjuvant therapy, offers prolonged survival, with 5-year survival rates of approximately 25%. However, for unresectable or disseminated disease, which constitutes the vast majority of cases, treatment is palliative. Despite increasing knowledge about the molecular pathology of pancreatic cancer and despite advances in treatment, the overall course of the disease is dismal, and reinforced efforts to reduce incidence and improve outcome are needed desperately.

Is there life after Buckley's formocresol? Part II - Development of a protocol for the management of extensive caries in the primary molar

OBJECTIVE

To produce a working clinical protocol for pulp therapy techniques in the extensively carious primary molar.

INTRODUCTION

The International Agency for Research on Cancer has recently classified formaldehyde as carcinogenic to human beings. As such, a medicament that can be used to replace formocresol in clinical practice should be identified.

METHODS

Part I of this paper explored the currently available alternative interventions and materials to formocresol in the form of a narrative review following an extensive literature search. Part II now presents the formation of a specialist group to establish an evidence-based protocol, for the management of the extensively carious primary molar.

CONCLUSION

A protocol and key points document have been developed to assist clinicians in their treatment planning. Areas for further postgraduate training are identified.

Genotoxic risk assessment of pathology and anatomy laboratory workers exposed to formaldehyde by use of personal air sampling and analysis of DNA damage in peripheral lymphocytes

A study was conducted to evaluate the genotoxic effect of occupational exposure to formaldehyde on pathology and anatomy laboratory workers. The level of exposure to formaldehyde was determined by use of passive air-monitoring badges clipped near the breathing zone of 59 workers for a total sampling time of 15 min or 8 h. To estimate DNA damage, a chemiluminescence microplate assay was performed on 57 workers before and after a 1-day exposure. Assessment of chromosomal damage was carried out by use of the cytokinesis-blocked micronucleus assay (CBMN) in peripheral lymphocytes of 59 exposed subjects in comparison with 37 controls matched for gender, age, and smoking habits. The CBMN assay was combined with fluorescent in situ hybridization with a pan-centromeric DNA probe in 18 exposed subjects and 18 control subjects randomized from the initial populations. Mean concentrations of formaldehyde were 2.0 (range <0.1-20.4 ppm) and 0.1 ppm (range <0.1-0.7 ppm) for the sampling times of 15 min and 8 h, respectively. No increase in DNA damage was detected in lymphocytes after a one-workday exposure. However, the frequency of binucleated micronucleated cells was significantly higher in pathologists/anatomists than in controls (16.9‰±9.3 versus 11.1‰±6.0, P=0.001). The frequency of centromeric micronuclei was higher in exposed subjects than in controls (17.3‰±11.5 versus 10.3‰±7.1) but the difference was not significant. The frequency of monocentromeric micronuclei was significantly higher in exposed subjects than in controls (11.0‰±6.2 versus 3.1‰±2.4, P<0.001), while that of the acentromeric micronuclei was similar in exposed subjects and controls (3.7‰±4.2 and 4.1‰±2.7, respectively). The enhanced chromosomal damage (particularly chromosome loss) in peripheral lymphocytes of pathologists/anatomists emphasizes the need to develop safety programs.

A review and meta-analysis of formaldehyde exposure and leukemia

Most reviews on the carcinogenicity of formaldehyde have focused on cancers of the respiratory tract because these cancer sites were thought to be most biologically plausible. However, two recent updated large industrial studies have found positive associations between some measures of formaldehyde exposure and increased leukemia, although another recent update of a large study did not find any association. We examine 18 epidemiology studies of workers exposed to formaldehyde where leukemia rates were reported. We summarize the findings across studies by using meta-analytic techniques to calculate the meta-relative risk values (mRR), confidence intervals, and heterogeneity of the risk estimates for several study characteristics. We also determine if publication or reporting biases may be affecting the estimates. We found a small increase in rate of leukemia overall among embalmers (mRR = 1.6, 95%CI 1.2-6.0), and pathologists/anatomists (mRR = 1.4, 95%CI 1.0-1.9). Industrial workers, who have been reported to have the highest formaldehyde exposures, had a mRR of 0.9 (95%CI 0.8-1.0). There was increased risk with increasing exposure in two large industrial studies, although the increased risk is one of these studies was not seen when an external comparison group is used. Also, another large industrial study with more highly exposure workers found decreased risk of leukemia among the highest exposed group. The long latency for leukemia deaths observed in the two industrial studies that reported increased risk was not consistent with a chemical carcinogen such as benzene. We found limited evidence of publication or reporting bias. On balance, these data do not provide consistent support for a relationship between formaldehyde exposure and leukemia risk.

Mortality from solid cancers among workers in formaldehyde industries

In industrial workers, formaldehyde exposure has been associated with cancer of the nasal cavities, nasopharynx, prostate, lung, and pancreas; however, these associations are inconsistent and remain controversial. Animals exposed to formaldehyde show excesses of nasal cancer. In an extended follow-up of a large cohort of formaldehyde-exposed workers, the authors evaluated mortality from solid cancers (1,921 deaths) among 25,619 workers (865,708 person-years) employed in 10 US formaldehyde-producing or -using facilities through 1994. Exposure assessment included quantitative estimates of formaldehyde exposure. Standardized mortality ratios and relative risks were calculated. Compared with that for the US population, mortality from solid cancers was significantly lower than expected among subjects exposed and nonexposed to formaldehyde (standardized mortality ratios = 0.91 and 0.78, respectively). Relative risks for nasopharyngeal cancer (nine deaths) increased with average exposure intensity, cumulative exposure, highest peak exposure, and duration of exposure to formaldehyde (p-trend = 0.066, 0.025, <0.001, and 0.147, respectively). Formaldehyde exposure did not appear to be associated with lung (744 deaths), pancreas (93 deaths), or brain (62 deaths) cancer. Although relative risks for prostate cancer (145 deaths) were elevated for some measures of formaldehyde exposure, the trend was inconsistent. In this cohort of formaldehyde-industry workers, some evidence was found of an exposure-response relation with mortality from nasopharyngeal cancer (based on small numbers) but not for cancers of the pancreas, brain, lung, or prostate.

Epidemiologic and etiologic factors of pancreatic cancer

Ranking fourth as a cause of death from cancer for men and women in the United States, pancreatic cancer represents a significant challenge for physicians and surgeons. In addition to the elderly, high-risk groups include blacks, men, smokers, and patients with certain preexisting diseases such as pancreatitis and long-standing diabetes. Various inherited genetic disorders cause approximately 5% to 10% of the total cases of pancreatic cancer. Smoking doubles the risk of pancreatic cancer. Control of smoking offers the best available strategy for reducing the incidence of this disease. Dietary measures to reduce the risk of pancreatic cancer include maintenance of normal body weight and consumption of a well balanced diet with adequate amounts of fruits and vegetables. Chronic pancreatitis caused by heavy alcohol consumption or, rarely, by an underlying inherited disorder is another strong risk factor, but because this benign disease is uncommon, elimination of this underlying cause would have minimal impact on the frequency of pancreatic cancer.