Occupational Chemical Exposures Research Articles

Residential Formaldehyde Exposure and the Risk of Congenital Heart Malformations

ISEE-228 Objective: There is some evidence that environmental air pollution might have influence on the risk of congenital heart malformations. The objective of our study was to estimate the risk of congenital heart malformations in different residential formaldehyde exposure levels. Material and Methods: We conducted the population-based case-control study among newborns of the Kaunas city, Lithuania, in 1999 to 2005. We compared 178 congenital heart malformations cases and 479 healthy controls by questionnaire information on sociodemographic characteristics, reproductive and maternal medical history, smoking, and occupational chemical exposures. We estimated annual means of formaldehyde concentrations in the residential districts and divided it into tertiles. We used the logistic regression analysis for the calculations of the adjusted odds ratios and 95% confidence intervals (CI). Results: After adjustment for maternal smoking, medical history, occupational chemical exposures, and residential hazards, the odds ratio of congenital heart malformations in the third residential formaldehyde exposure tertile was 1.27; 95% CI 0.62 to 2.59 as compared with the first tertile. Conclusions: Residential formaldehyde exposure showed a tendency for increased congenital heart malformations risk. Solving environmental problems of ambient air pollution would benefit in reducing the risk of childhood malformations.

Nested case‐control study of occupational chemical exposures and prostate cancer in aerospace and radiation workers

To date, little is known about the potential contributions of occupational exposure to chemicals to the etiology of prostate cancer. Previous studies examining associations suffered from limitations including the reliance on mortality data and inadequate exposure assessment. We conducted a nested case-control study of 362 cases and 1,805 matched controls to examine the association between occupational chemical exposures and prostate cancer incidence. Workers were employed between 1950 and 1992 at a nuclear energy and rocket engine-testing facility in Southern California. We obtained cancer-incidence data from the California Cancer Registry and seven other state cancer registries. Data from company records were used to construct a job exposure matrix (JEM) for occupational exposures to hydrazine, trichloroethylene (TCE), polycyclic aromatic hydrocarbons (PAHs), benzene and mineral oil. Associations between chemical exposures and prostate cancer incidence were assessed in conditional logistic regression models. With adjustment for occupational confounders, including socioeconomic status, occupational physical activity, and exposure to the other chemicals evaluated, the odds ratio for low/moderate TCE exposure was 1.3; 95%CI = 0.8 to 2.1, and for high TCE exposure was 2.1; 95%CI = 1.2 to 3.9. Furthermore, we noted a positive trend between increasing levels of TCE exposure and prostate cancer (P-value for trend = 0.02). Our results suggest that high levels of TCE exposure are associated with prostate cancer among workers in our study population.

Environmental and Behavioral Factors and the Risk of Non-Hodgkin Lymphoma

Investigators around the world have reported that incidence and mortality rates for non-Hodgkin lymphoma (NHL) increased steadily and substantially over the last five decades of the 20th century. Identifying what changes in the environment or in behavior fueled this epidemic still presents a major

The Evolution of Epidemiologic Research

Fhe term was first coined to describe several changes in the way science I (particularly physics) was conducted in industrial nations during and after World War II. These changes included the assembly of staffs (usually multidisciplinary) to work in laboratories, using machines, all requiring budgets. The proximal stimulus for this was the belief that this was the only way to make rapid progress in developing a variety of critical defense-related products for the war effort, including the proximity fuse, radar, and the atomic bomb. This general approach, however, continued after the war, extending to particle research in general, and into other areas of physics as well (eg, laser technology). As time went on, other disciplines developed significant big science components as well, perhaps most notably astronomy. These trends have only recently entered the biologic sciences with the most graphic example being the changes in genomic research over the last 15 years. So how did big science come to epidemiology? The process has been somewhat different for classic epidemiology and molecular epidemiology. For the classic ap proaches, the need developed in a gradual and subtle manner. Up until 25 to 30 years ago, most epidemiologic research could be described as a cottage industry. There were a number of programs, but most were comprised of a small number of investigators with expertise largely limited to epidemiology, medicine, and biostatistics. Each investigator worked on his own studies, which were generally small (a study of 300 cases of a disease was viewed as a large study) using a limited study team and run on a relatively small budget. The principal investigator tended to design a study, develop the interview and abstract forms, train and supervise the data collectors (often doing much of it himself), code the data, and conduct the analyses on a calculator or perhaps through simple computer programs he could write himself. Although all this sounds rather quaint to young investigators today, it actually worked quite well, and this was a productive era for meaningful epidemiologic discov eries. The success of these approaches was largely due to the objectives of the investi gations. For the most part, the interest was in identifying large risks associated with obvious and easily measured exposures with a focus only on main effects. In my own area of cancer epidemiology, this was the era when many of the major risks with tobacco and alcohol consumption, ionizing radiation, occupational chemical exposures, medicinal agents, and reproductive factors were elucidated. Although many studies continue to focus on these objectives, over the last 30 years, there has been an increasing interest in identifying relatively low levels of risk, often associated with low-level or difficult-to measure exposures, and a concern about effects in subgroups (effect modification). This has resulted in the need for larger studies (now a study of 300 cases is often considered small), larger, more interdisciplinary study teams, and sophisticated, technology-intensive analytic methods-all of which require substantially larger budgets.

When and Why Do Experts Perform Exposure Measurements? An Exploratory Study of Safety Engineers, Work Environment Inspectors, and Occupational Hygienists

The aim of this study was to describe experts' decision processes leading to measurements of occupational chemical exposure. Safety engineers, clinical occupational hygienists, and work environment inspectors (four from each group) were interviewed according to a semistructured scheme. We analyzed: (i) perceived triggers for measurements, (ii) the experts' decision criteria for performing measurements when there was a trigger, and (iii) sampling strategy. Regarding triggers, all safety engineers reported a “request” from, for example, an employer; all work environment inspectors reported “legal demands;” and all clinical occupational hygienists reported “symptoms among workers.” As a decision criterion, all the interviewees reported that they measured only if they expected sufficiently high levels. The results of the present study highlight factors that trigger measurements and are of importance in determining whether measurements will be performed. These factors appear to be related to the expert's professional role and may bias the assessment of exposure. Thus, when using data from routine measurements done by experts, the possibility of a bias needs to be considered.

Nested Case-Control Study of Occupational Chemical Exposures and Prostate Cancer Among Workers Using a Job Exposure Matrix

Nested Case-Control Study of Occupational Chemical Exposures and Prostate Cancer Among Workers Using a Job Exposure Matrix

Prevalence of Respiratory Symptoms among Workers in Industries of South Tehran, Iran

The aim of the present study was to determine the prevalence of respiratory symptoms from occupational lung hazards among workers in industries of south Tehran, IRAN. This was a cross-sectional study in which by multistage random sampling items on demographic characteristics, cigarette smoking, occupational history and respiratory symptoms were collected of workers. The mean age of the workers was 38.5 (SD = 10.2) yr: age ranged from 19 to 70 yr. Of 880 workers under study, 252 (28.7%) were smoking. Also, it has been observed that workers exposed in the workplace with occupational chemical exposures such as dust, gas and fume pollutants. The prevalence of respiratory symptoms was cough (20.7%), phlegm (41.6%), dyspnea (41.7%), feel tightness (27.4%) and nose irritation (23.5%). Occupational exposures among workers in industries of south Tehran may cause respiratory symptoms and respiratory disorders, engineering controls and industrial hygiene is recommended.

Reproductive history, occupational exposures, and thyroid cancer risk among women textile workers in Shanghai, China

Thyroid cancer risk has been previously associated with increased age at first pregnancy and history of miscarriage. Occupational risk factors for thyroid cancer, with the exception of radioactive iodine, have not been well investigated. We conducted a case-cohort study nested in a cohort of 267,400 female textile workers in Shanghai, China, who had been followed for cancer incidence during 1989-1998. The analysis included 130 incident thyroid cases and 3,187 subcohort non-cases. Reproductive history was determined by questionnaire at baseline. Historical exposures were reconstructed from work history and information on factory processes and exposures. Cox proportional hazards analysis was performed to estimate hazard ratios (HR) for reproductive factors and occupational exposures. Associations were observed between thyroid cancer and employment in jobs with 10 or more years of benzene exposure (HR 6.43, 95% CI: 1.08, 38) and formaldehyde exposure (HR 8.33, 95% CI: 1.16, 60). Administration workers also had an increased risk (HR 1.56, 95% CI: 1.08, 2.25). No associations between examined reproductive factors and thyroid cancer were observed in this study. Despite statistically imprecise risk estimates, the findings suggest potential associations with some occupational chemical exposures in this cohort of textile workers.

Declining Sex Ratio in a First Nation Community

Members of the Aamjiwnaang First Nation community near Sarnia, Ontario, Canada, voiced concerns that there appeared to be fewer male children in their community in recent years. In response to these concerns, we assessed the sex ratio (proportion of male births) of the Aamjiwnaang First Nation over the period 1984–2003 as part of a community-based participatory research project. The trend in the proportion of male live births of the Aamjiwnaang First Nation has been declining continuously from the early 1990s to 2003, from an apparently stable sex ratio prior to this time. The proportion of male births (m) showed a statistically significant decline over the most recent 10-year period (1994–2003) (m = 0.412, p = 0.008) with the most pronounced decrease observed during the most recent 5 years (1999–2003) (m = 0.348, p = 0.006). Numerous factors have been associated with a decrease in the proportion of male births in a population, including a number of environmental and occupational chemical exposures. This community is located within the Great Lakes St. Clair River Area of Concern and is situated immediately adjacent to several large petrochemical, polymer, and chemical industrial plants. Although there are several potential factors that could be contributing to the observed decrease in sex ratio of the Aamjiwnaang First Nation, the close proximity of this community to a large aggregation of industries and potential exposures to compounds that may influence sex ratios warrants further assessment into the types of chemical exposures for this population. A community health survey is currently under way to gather more information about the health of the Aamjiwnaang community and to provide additional information about the factors that could be contributing to the observed decrease in the proportion of male births in recent years.

The Recommended Role of Exposure Biomarkers for the Surveillance of Environmental and Occupational Chemical Exposures in Military Deployments: Policy Considerations

A lack of individual exposure information limited the evaluation of exposure-outcome relationships after the Gulf War. Exposure concerns during Operation Enduring Freedom and Iraqi Freedom deployments have increased interest in individual environmental and occupational chemical exposure assessment. Currently, deployment assessments are conducted using intermittent ambient air monitoring, occasional focused evaluations based on these results, and postdeployment questionnaire documentation of exposure and/or health concerns. Although this strategy is an improvement over previous practice, it has limitations, including a reliance on evidence of an acute problem, to initiate in-depth health evaluation. Exposure biomarkers may have the potential to overcome some of the limitations of current environmental and occupational exposure assessment tools. This article examines current exposure assessment methods, reviews emerging technologies, and recommends a phased approach to introducing exposure biomarkers into a comprehensive occupational and environmental health surveillance program.

The opportunities and obstacles to collaboration between the developing and developed countries in the field of occupational health.

The 2.4 billion working people in the developing countries often have to endure employment conditions, which do not meet even basic occupational safety and health (OSH) standards. The lack of work safety, excessive work loads, and occupational physical, chemical and biological exposures result in occupational diseases, injuries and as many as 1.2 million fatalities each year. Furthermore, as little as 15% of workers in the developing countries have access to occupational health and safety services. Some collaboration between the industrialized and developing countries in the field of OSH has been practiced for 30 years but its volume has been modest compared to other sectors of development assistance. The lessons learned from 30 years of experience are that the most important OSH improving factors in developing countries include legal and policy instruments, national OSH programs, infrastructure for OSH implementation, and OSH services. The establishment of OSH expert human resources, centers serving as engines for research, training, as well as information and registration systems can also be considered as key factors in any such collaboration. A convincing government OSH policy, and close cooperation between social partners and the government are also critical factors that guarantee sustainable OSH programs in a developing country over a long-term basis.

Risk Factors for the Development of Severe ME/CFS—

The pilot phase is reported of a case-control study to determine risk factors for severe CFS/ME. One hundred fifty-seven members of the ME Association, selected at random, were sent postal questionnaires, with a 56% response. The Barthel index was used as a validated proxy measure to distinguish severe disease (cases) and those less severe. Thirteen of 88 respondents had severe disease, and 44 mild disease. Two matched controls from the ‘mild’ group were selected per case. Of possible risk factors, odds ratios greater than 2 were found for comorbidities, damaging initial treatment and occupational chemical exposure, although in this study they were not statistically significant. These data suggest that additional studies are warranted.

Risk of laryngeal cancer by occupational chemical exposure in Turkey.

Laryngeal cancer is the second most common cancer among men in Turkey. In this hospital based case-control study, we evaluated laryngeal cancer risks from occupational chemical exposures. We analyzed 940 laryngeal cancer cases and 1519 controls. Occupational history, tobacco, and alcohol use and demographic information were obtained by a questionnaire. The job and industries were classified by special seven-digit codes. We calculated odds ratios (ORs) and 95% confidence intervals (CIs) based on a developed exposure matrix for chemicals, including diesel exhaust, gasoline exhaust, polycyclic aromatic hydrocarbons (PAHs), formaldehyde, and solvents. An excess of laryngeal cancer occurred with diesel exhaust (OR=1.5, 95% CI=1.3-1.9), gasoline exhaust (OR=1.6, 95% CI=1.3-2.0), and PAHs (OR=1.3, 95% CI=1.1-1.6). There was a dose-response relationship for these substances with supraglottic cancers (P<0.000). The PAH association only occurred among those who also had exposure to diesel exhaust.

Synergistic effect of hepatitis virus infection and occupational exposures to vinyl chloride monomer and ethylene dichloride on serum aminotransferase activity

Aims: To study the synergistic effect of occupational chemical exposure and hepatitis virus infection on serum aminotransferase activity. Methods: A total of 568 male workers who were employed in five...

Maternal Occupational Chemical Exposures and Biotransformation Genotypes as Risk Factors for Selected Congenital Anomalies

In a case-control study using an assessment of occupational tasks by an industrial hygienist, the authors investigated whether women's occupational exposures increased risks of delivering infants with cleft palate (CP), cleft lip with or without cleft palate (CLP), conotruncal defects, or limb deficiencies. For CP and CLP, exposures were further considered in the presence/absence of infant genetic variants for glutathione-S-transferase M1, glutathione-S-transferase T1, and N-acetyltransferases 1 and 2. The study included 1987-1989 California stillbirths and livebirths. Telephone interviews were conducted with mothers of 662 CLP and CP cases, 207 conotruncal defect cases, 165 limb deficiency cases, and 734 nonmalformed controls. Occupational tasks were assigned to a priori-defined exposure categories: 74 chemical groups and nine "end-use" chemical groups. Odds ratios of 1.5 or greater were observed for a small number of exposure-defect comparisons. Risks associated with end-use groups revealed odds ratios of 1.5 or greater for exposures to dyes and pigments (conotruncal and CP), propellants (CP), and insecticides (conotruncal and CP). Numerous odds ratios of 2.5 or greater were observed for combined effects of exposures and homozygous mutant genotypes, particularly for CP. Although potential associations were observed, most results suggested that maternal occupational chemical exposures did not contribute substantially to the occurrence of these anomalies in this California population.

Biological And Health Effects Of Exposure To Kerosene-Based Jet Fuels And Performance Additives

Over 2 million military and civilian personnel per year (over 1 million in the United States) are occupationally exposed, respectively, to jet propulsion fuel-8 (JP-8), JP-8 +100 or JP-5, or to the civil aviation equivalents Jet A or Jet A-1. Approximately 60 billion gallons of these kerosene-based jet fuels are annually consumed worldwide (26 billion gallons in the United States), including over 5 billion gallons of JP-8 by the militaries of the United States and other NATO countries. JP-8, for example, represents the largest single chemical exposure in the U.S. military (2.53 billion gallons in 2000), while Jet A and A-1 are among the most common sources of nonmilitary occupational chemical exposure. Although more recent figures were not available, approximately 4.06 billion gallons of kerosene per se were consumed in the United States in 1990 (IARC, 1992). These exposures may occur repeatedly to raw fuel, vapor phase, aerosol phase, or fuel combustion exhaust by dermal absorption, pulmonary inhalation, or oral ingestion routes. Additionally, the public may be repeatedly exposed to lower levels of jet fuel vapor/aerosol or to fuel combustion products through atmospheric contamination, or to raw fuel constituents by contact with contaminated groundwater or soil. Kerosene-based hydrocarbon fuels are complex mixtures of up to 260+ aliphatic and aromatic hydrocarbon compounds (C 6 -C 17+ ; possibly 2000+ isomeric forms), including varying concentrations of potential toxicants such as benzene, n-hexane, toluene, xylenes, trimethylpentane, methoxyethanol, naphthalenes (including polycyclic aromatic hydrocarbons [PAHs], and certain other C 9 -C 12 fractions (i.e., n-propylbenzene, trimethylbenzene isomers). While hydrocarbon fuel exposures occur typically at concentrations below current permissible exposure limits (PELs) for the parent fuel or its constituent chemicals, it is unknown whether additive or synergistic interactions among hydrocarbon constituents, up to six performance additives, and other environmental exposure factors may result in unpredicted toxicity. While there is little epidemiological evidence for fuel-induced death, cancer, or other serious organic disease in fuel-exposed workers, large numbers of self-reported health complaints in this cohort appear to justify study of more subtle health consequences. A number of recently published studies reported acute or persisting biological or health effects from acute, subchronic, or chronic exposure of humans or animals to kerosene-based hydrocarbon fuels, toconstituent chemicals of these fuels, or to fuel combustion products. This review provides an in-depth summary of human, animal, and in vitro studies of biological or health effects from exposure to JP-8, JP-8 +100, JP-5, Jet A, Jet A-1, or kerosene.

Color Vision and Occupational Chemical Exposures: II. Visual Functions in Non-Exposed Subjects

This paper presents data on visual functions (visual acuity, contrast sensitivity, and several tests of color vision), in a group of 199 non-exposed healthy subjects with an even distribution over the age range 18–65 years, and sex. Although subjects with obvious congenital color vision deficiencies were removed from the analyses (four males), females were superior to males on several of the color vision tests applied. Age influenced visual acuity and contrast sensitivity, while color discrimination was less affected. Correlations between functions of the right and the left eye in the individual subjects were rather low, ranging from 0.40 to 0.73. Correlations between visual acuity and contrast sensitivity on the one hand and color discrimination ability on the other hand were still lower ( r<0.20). These low correlations between functions in the two eyes support the need for testing each eye separately.

Color Vision and Occupational Chemical Exposures: I. An Overview of Tests and Effects

The paper presents a summary of the literature published until December 2000 on effects from some industrial chemical exposures on color perception, as well as short descriptions of the tests applied. Several different tests have been used to study acquired alterations of color vision. These changes are frequently found in the blue–yellow axis. Many of the tests were originally designed to detect congenital alterations in the red–green axis, and thus have relatively low sensitivity when studying chemically induced deficits in color perception. At present, the Lanthony D15-desaturated panel seems most suitable for application in industrial settings, since it is clearly the most sensitive and easily administered test. Color vision seems to be a physiological function very sensitive to several chemicals. The potency of industrial chemicals to induce color vision deficiencies has often been investigated during the last two decades. The chemicals most frequently studied are different solvents and mercury. Pronounced effects on color perception have been reported following chronic exposure to organic solvents such as styrene, carbon disulphide, perchloroethylene, n-hexane and solvent mixtures, and to organic as well as inorganic mercury. The effect of occupational toluene exposure seems not as well established, since only slight effects and several negative studies have been reported. For some of these compounds the effect on color vision has been further established through the finding of clear dose–effect relationships. In a few cases, even acute exposure situations, e.g. exposure to toluene for a few hours or acute alcohol intake, seem to affect color perception. Follow-up studies are needed to investigate the possible reversibility of effects in relation to discontinued or reduced exposures.

Environmental risk factors and gender in nasal polyposis.

The aetiology of nasal polyps remains obscure. Although clinically associated with asthma, notably in women, there is a marked male preponderance of polyposis. This study aimed to explore environmental pollutant triggers and gender differences in risk factors for nasal polyps. In total, 900 patients having surgery for polyposis and 120 new patients with nasal polyps completed a questionnaire with regard to occupational dust and chemical exposure. The male to female ratio was 2:1, and 52% were smokers, although only 37% of women smoked compared with 66% of men. Exposure to occupational dusts and chemicals was noted in 45% (retrospective) and 53% (prospective) of respondents. Women were 1.6 times more likely to be asthmatic and 2.7 times more likely to have allergic rhinitis than men. Men were 2.25 times more likely to be smokers and 2.48 times more likely to have been exposed to chemicals and dusts than women (all statistically significant differences). No significant gender associations were found for hayfever, eczema, aspirin intolerance, alcohol intake or hobby dust exposure.

Models of unexplained symptoms associated with occupational and environmental exposures.

Unexplained illnesses characterized by nonspecific, multisystem complaints are often attributed to occupational or environmental chemical exposures. This raises difficulties for the regulatory authorities, who are frequently unable to agree on the existence, nature, or source of such illnesses. It is proposed that many of these difficulties derive from an adherence to a traditional medical model of disease and that the application of a biopsychosocial approach would be more effective for both research and individual case management. A number of models derived from the field of health psychology are discussed in terms of their application to occupational and environmental syndromes. A specific example is described that relates to the health problems experienced by sheep farmers in the United Kingdom who are exposed to organophosphate-based pesticides. The source of their complaints and the responses of the health professionals and the regulatory authorities are discussed within the context of a biopsychosocial approach that focuses on illness rather than on organic disease as the unit of study and explores the interaction between the various physical and psychosocial variables involved. It is proposed that this approach, which is already well established in the fields of human and social sciences, should be adopted more readily by those concerned with occupational and environmental epidemiology.