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Biomedical subjects

Ellen A Eisen

Publications and source records attributed to Ellen A Eisen.

At least 19 recordsLinked to original sources

Oil and gas well development and coccidioidomycosis risk in Kern County, CA, USA: a case-crossover study.

BACKGROUND: Coccidioidomycosis is an emerging fungal disease caused by inhaling Coccidioides spp spores. As spores reside in soil, activities that disturb soil and generate dust can aerosolise and transport the pathogen. The oil and gas industry has been extensively developed in some regions that are endemic for Coccidioides spp and has been associated with dust emissions. Although several adverse health outcomes have previously been associated with oil and gas development, its impact on coccidioidomycosis risk has not been investigated. We aimed to estimate the association between exposure to oil and gas well development (ie, wells in preproduction) and risk of coccidioidomycosis among residents living near new wells. METHODS: In this case-crossover study, we obtained information on reported coccidioidomycosis cases and oil and gas well development between 2007 and 2022 in Kern County, CA, USA. We then compared exposure to preproduction wells within 5 km of each individual's place of residence during both hazard (ie, the 49-139 days before case onset) and control periods using conditional logistic regression. FINDINGS: During the study period, 658 108 (72·4%) of 909 282 of Kern County residents lived within 5 km of at least one preproduction well, and 116 020 (12·8%) lived within 5 km of 23 or more preproduction wells within a single 90-day period. We estimated that the odds of coccidiomycosis incidence were 12·5% (95% CI 5·8-19·6) higher in the 90 days following exposure to at least one preproduction well within 5 km of an individual's place of residence and that the odds of infection increased by 0·7% (0·4-0·9) for each additional preproduction well developed within this distance. INTERPRETATION: These findings support a previously-unrecognised association between the development of oil and gas wells and transmission of coccidioidomycosis, potentially driven by dust generation. Given the prevalence of oil and gas development in the study region, its impact on coccidioidomycosis incidence might be large. FUNDING: National Institutes of Health, National Science Foundation.

Journal Article↗

Rectal cancer and exposure to metalworking fluids in the automobile manufacturing industry.

BACKGROUND: Rectal cancer has been previously associated with exposure to metalworking fluids in a cohort mortality study of autoworkers. OBJECTIVE: To better specify the exposure-response relationship with straight metalworking fluids (mineral oils) by applying non-parametric regression methods that avoid linearity constraints and arbitrary exposure cut points and by lagging exposure to account for cancer latency, in a nested case-control analysis. METHODS: In addition to the classical Poisson regression with categorical exposure, survival models with penalised splines were used to estimate the exposure-response relationship between cumulative exposure to straight metalworking fluid and mortality from rectal cancer. Exposures to water-based metalworking fluids were treated as potential confounders, and all exposures were lagged by 5, 10, 15 and 20 years to account for cancer latency. The influence of the highest exposures was dealt with by a log transformation and outlier removal. The sensitivity of the penalised splines to alternative criteria for model selection and to the placement of knots was also examined. RESULTS: The hazard ratio for mortality from rectal cancer increased essentially linearly with cumulative exposure to straight metalworking fluid (with narrow confidence bands) up to a maximum of 2.2 at the 99th centile of exposure and then decreased (with wide confidence bands). Lagging exposure up to 15 years increased the initial steepness of the curve and raised the maximum hazard ratio to 3.2. CONCLUSIONS: Non-parametric smoothing of lagged exposures has shown stronger evidence for a causal association between straight metalworking fluid and rectal cancer than was previously described using standard analytical methods. This analysis suggests an exposure-response trend that is close to linear and statistically significant over most of the exposure range and that increases further with lagged exposures. Smoothing should be regularly applied to environmental studies with quantitative exposure estimates to refine characterisation of the dose-response relationship.

Adult↗

Cancer mortality among textile workers in Shanghai, China: a preliminary study.

OBJECTIVE: We assessed the association between cotton textile work and cancer mortality. METHODS: The cancer mortality experience of 912 (444 cotton, 468 silk) textile workers in Shanghai, China, was compared. Workers were followed from 1981 to 2003. The associations between cotton textile work and death due to all cancers combined (with and without lung cancer) and to gastrointestinal cancers were estimated with Cox models, adjusting for age, work years, and pack-years. RESULTS: There were 69 deaths. The adjusted hazard rate ratio (HR) was 2.10 (95% confidence interval [CI], 0.98-4.47) for all cancers combined and 2.56 (95% CI, 1.14-5.74) after excluding lung cancer. For gastrointestinal cancers, the adjusted HR was 2.09 (95% CI, 0.83-5.27). CONCLUSIONS: These preliminary data suggest that, with the exception of lung cancer, cotton workers have significantly higher cancer mortality rates than silk workers.

Adult↗

Occupational exposure to metalworking fluids and risk of breast cancer among female autoworkers.

BACKGROUND: Metalworking fluids (MWF) are used for lubrication during metal manufacturing. Previous studies have observed increased risks of several cancers among MWF-exposed workers. We hypothesized that MWF may be associated with risk of breast cancer because they can contain carcinogenic or endocrine-disrupting chemicals. METHODS: We conducted a case-control study nested in a cohort of 4,680 female automobile workers employed for at least 3 years between 1/1/41 and 1/1/85, with follow-up through 1994. Cases were identified using the National Death Index (NDI), Michigan cancer registries, and company records. Detailed quantitative MWF exposure data were available for each subject, although data on known breast cancer risk factors were not. RESULTS: Ninety-nine cases of breast cancer and 626 matched controls were identified. There was a weak positive association between lifetime cumulative exposure to soluble MWF and breast cancer risk, but no evidence of association with either straight or synthetic fluids. When exposure was divided into time-windows, the association was strongest for soluble MWF in the decade preceding diagnosis. Controlling for earlier exposures, there was an odds ratio of 1.18 (95% CI=1.02-1.35) per mg/m3-year of cumulative exposure to soluble MWF in this 10-year period. CONCLUSION: This hypothesis-generating study provides some preliminary evidence for an association between exposure to soluble MWF and increased risk of breast cancer. Additional studies of MWF and breast cancer, with data on known breast cancer risk factors, are warranted.

Adult↗

Risk of breast cancer among enlisted Army women occupationally exposed to volatile organic compounds.

BACKGROUND: The military presents a unique opportunity to study the incidence of disease in a population with complete knowledge of person-time and occupation. Women in the Army are employed more frequently in non-traditional, industrial jobs such as auto mechanic and motor transport operators than in the general US population, increasing the probability of exposure to industrial chemicals. A cohort to investigate the risk of breast cancer among active duty Army women occupationally exposed to volatile organic chemicals (VOCs) was constructed. METHODS: Age-adjusted incidence rates for breast cancer were calculated for more than 270,000 enlisted women who served between 1980-1996. Twenty-one VOCs, described in previously published literature as having a potential risk of breast cancer, were identified in an Army industrial hygiene survey database. Job title histories were linked to workplace chemical evaluations conducted by Army industrial hygienists, which included a subjective exposure potential rating (high, medium, low, and none) for each VOC. Poisson regression analysis was used to evaluate the association between the exposure rating by job title and breast cancer. RESULTS: The incidence of breast cancer in the cohort was significantly elevated in women younger than 35 years of age, especially among black women, when compared to the age-specific rates in the general population. Women who worked in occupations with a moderate to high exposure potential to at least one VOC had a 48% increased risk (P < 0.05) of breast cancer while on active duty between 1980-1996 when compared to those women with low to no exposure potential. CONCLUSIONS: This study provides preliminary evidence that exposure to one or more of the study VOCs is associated with an increased risk of breast cancer. Further substance-specific, quantitative analyses are warranted.

Adult↗

A biological approach to characterizing exposure to metalworking fluids and risk of prostate cancer (United States).

OBJECTIVE: Prostate cancer is hormone-related and chemicals that interfere with hormones may contribute to carcinogenesis. In a cohort of autoworkers we characterized exposure to metalworking fluids (MWF) into age windows with homogenous biological risk for prostate cancer, and examined exposure-response relationships using semi-parametric modeling. METHODS: Incident cases (n=872) were identified via Michigan cancer registry from 1985 through 2000. Controls were selected using incidence-density sampling, 5:1 ratio. Using a hormonal-based model, exposure was accumulated in three windows: (1) late puberty, (2) adulthood, and (3) middle age. We used penalized splines to model risk as a smooth function of exposure, and controlled for race and calendar year of diagnosis in a Cox model. RESULTS: Risk of prostate cancer linearly increased with exposure to straight MWF in the first window, with a relative risk of 2.4 per 10 mg/m(3)-years. Autoworkers exposed to MWF at a young age also had an increased risk associated with MWF exposure incurred later in life. For soluble MWF there was a slightly increased risk in the third window. CONCLUSIONS: Exposure characterization based on a hormonal model identified heightened risk with early age of exposure to straight MWF. Results also support a long latency period for exposure related prostate cancer.

Adolescent↗

Determinants of airborne fiber size in the glass fiber production industry.

Size distributions of airborne fiber exposures should be characterized for studies of respiratory disease because size determines the region of the lung where a fiber will deposit and its ability to produce toxic effects in cells. Yet fiber size is not measured precisely with standard air sampling methods. Specific fiber dimensions hypothesized to have biologic activity have been proposed, but these have not been evaluated in epidemiologic studies because there has not been a way to account for fiber size in historical air monitoring data. In this study, methods were developed to predict fibrous aerosol size fractions generated during glass wool fiber production using regression models and factors related to bulk fiber products and processing. A set of air samples representing a range of products and process applications was collected in eight fiber glass production facilities. The samples were analyzed more intensively than standard methods require. For each air sample, total fiber size distributions were measured using electron microscopy and two proportions were then calculated: (1) fibers meeting the size criteria of the standard NIOSH Method 7400 B rules method (pB), and (2) fibers meeting the size criteria for a biologically based exposure index, the hypothetically active fiber (HAF1) index (pH1). The fiber size proportions were used as dependent variables in regression models with production process factors. It was found that two factors, the nominal diameter of the bulk fiber product and whether oil was applied to it, determine more than 80% of the variability in the proportions (for the pB model, R2 = 0.86; for the pH1 model, R2 = 0.82). Using these two predicted proportions, it is possible to estimate the concentration of fibers in the biologically based HAF1 size fraction from a standard fiber concentration measurement. The models developed here can be used to size-adjust historical fiber concentration measurements for use in epidemiologic studies of respiratory disease.

Air Pollution, Indoor↗

Prostate cancer incidence in relation to time windows of exposure to metalworking fluids in the auto industry.

BACKGROUND: Exposure to metalworking fluids has been previously associated with prostate cancer mortality in a cohort of autoworkers. Our objective was to further explore this finding in a study of prostate cancer incidence in the same cohort, with reduced misclassification of outcome. METHODS: We conducted a nested case-control study in the General Motors cohort of autoworkers. Incident cases of prostate cancer (n = 872) were identified via the Michigan Cancer Registry from 1985 through 2000. Controls were selected using incidence-density sampling with 5:1 ratio. Using cumulative exposure (mg/m-years) as the dose metric, we first examined varying lengths of lags (0-25 years). Then, we evaluated consecutive windows of exposure: 25 or more years before risk age, and fewer than 25 years. We used penalized splines to model the relative risk as a smooth function of exposure, and adjusted for race and calendar year of diagnosis in a Cox model. RESULTS: Risk of prostate cancer increased with exposure to soluble and straight fluids 25 years or more before risk age but not with exposure in the last 25 years. The relationship with soluble fluids was piecewise linear, with a small increase in risk at lower exposures followed by a steeper rise. By contrast, the relationship with straight fluids was linear, with a relative risk of 1.12 per 10mg/m-years of exposure (95% confidence interval = 1.04-1.20). CONCLUSIONS: Exposure to oil-based fluids, soluble and straight, is modestly associated with prostate cancer risk among autoworkers, with a latency period of at least 25 years.

Adult↗

The ADH1C polymorphism modifies the risk of squamous cell carcinoma of the head and neck associated with alcohol and tobacco use.

Alcohol consumption interacts with tobacco use to increase the risk of head and neck squamous cell carcinoma (HNSCC). Alcohol is eliminated through oxidation by alcohol dehydrogenase (ADH). The ADH1C gene is polymorphic and the ADH1C*1 allele metabolizes ethanol to acetaldehyde at a higher rate than the variant ADH1C*2 allele. This polymorphism has been reported to alter the risk of HNSCC associated with alcohol use, although the literature differs in the estimates of both the magnitude and direction of this effect modification. We have investigated the association between the established risk factors for HNSCC and variant genotypes of ADH1C in a case-control study in the greater Boston area. ADH1C genotypes were determined from 521 cases and 599 population-based controls. The odds ratio (OR) for HNSCC associated with >26 drinks per week was 3.7 [95% confidence interval (95% CI), 2.4-5.7], whereas the OR for smoking >58 pack-years was 5.6 (95% CI, 3.8-8.4). The combination of heavy smoking and heavy drinking significantly interacted to produce an OR of 17.3 (95% CI, 7.8-38.3). In cases and controls, respectively, 16% and 14% were ADH1C*1-1, 46% and 46% were ADH1C*1-2 and 38% and 40% were ADH1C*2-2. There was a significant interaction of alcohol use and genotype (P = 0.05), with an estimated oral cancer risk in heavy drinkers of 7.1 (95% CI, 2.3-22.0) for homozygous variants compared with an OR of 2.3 (95% CI, 1.4-3.8) for ADH1C homozygous wild type or heterozygous individuals (controlling for smoking, age, race, and gender). These findings suggest that the ADH1C*2-2 genotype is associated with susceptibility to smoking and drinking-related HNSCC by modifying the biologically effective dose of alcohol.

Aged↗

Registry-based case-control studies of liver cancer and cancers of the biliary tract nested in a cohort of autoworkers exposed to metalworking fluids.

OBJECTIVE: Results are presented for a registry-based study of hepatobiliary cancer (liver and biliary tract) nested in a cohort of workers from three automobile manufacturing plants with potential exposure to metalworking fluids. METHODS: Altogether 63 cases of hepatobiliary cancer were identified from the cohort by the Michigan cancer registries. Each case was matched to 10 controls. Odds ratios (OR) were estimated in conditional logistic regression models for lifetime exposure to straight, soluble, and synthetic metalworking fluid and fluid components. RESULTS: Overall, hepatobiliary cancer was not associated with exposure to metalworking fluids. However, when the cases were stratified into liver cancer (N = 39) and biliary tract cancer (N = 24) the risk was nonhomogeneous across the two categories. While liver cancer was not associated with exposure to metalworking fluids, the results suggested a possible excess risk of biliary tract cancer with more than 1.0 mg/m3-years of exposure to straight metalworking fluids [OR 2.7, 95% confidence interval (95% CI) 0.9-7.6], as well as any exposure to chlorinated paraffins (OR 3.9, 95% CI 0.9-17). When exposures to straight metalworking fluids were separated into 10-year exposure periods, the odds ratio increased to 6.24 (95% CI 1.62-24.16) for exposures occurring > 20 years prior to the risk date. CONCLUSIONS: There is limited evidence that exposure to straight metalworking fluids is associated with biliary tract cancer. The small numbers of cases of these rare cancers were reflected in the wide confidence intervals, and these findings need to be examined further in other exposed populations.

Adult↗

Quantitative evaluation of the effects of uncontrolled confounding by alcohol and tobacco in occupational cancer studies.

BACKGROUND: Uncontrolled confounding by personal exposures like smoking can limit the inferential power of occupational cohort studies. We developed and demonstrate a refinement of an existing type of sensitivity analysis, indirect adjustment, for evaluating the potential magnitude of confounding by alcohol and tobacco. Results of a large retrospective cohort study of laryngeal cancer and exposure to metalworking fluids (MWF) are used to illustrate the methods. METHODS: Data on smoking and drinking habits representative of the study cohort were obtained from a sample of US manufacturing workers from the 1977 National Health Interview Survey (NHIS). Two different mechanisms were assumed to affect the distribution of confounding factors between MWF exposure groups: socially determined and chance differences. Chance variation was investigated with Monte Carlo sampling from the NHIS survey distribution of smoking and drinking. An upper bound on systematic differences in smoking and drinking was set by assuming that differences between exposure groups within the same unionized blue collar workforce were very unlikely to be larger than differences between blue and white collar manufacturing workers in the NHIS data. RESULTS: Under plausibly large differences in smoking and drinking habits among MWF exposure groups occurring by either mechanism, the exposure-risk association was unlikely to have been over- or under-estimated by as much as 20%. CONCLUSIONS: When comparing exposure groups within the same working population, it is unlikely that either systematic or chance differences in smoking and drinking habits will cause as much as a 20% change in the relative risk in large studies. While this study focused on an occupational exposure and laryngeal cancer, there are many situations in which epidemiologists are concerned that unmeasured 'lifestyle factors' may differ among exposure groups, and it would appear that the likely confounding effect of such differences will often be modest.

Adult↗

Polyisocyanates in occupational environments: a critical review of exposure limits and metrics.

BACKGROUND: Determination of polyisocyanates is important because they are a major contributor of exposure to the isocyanate functional group in many workplace environments and are capable of inducing sensitization and asthma. However, with multiple different measurement metrics in use, comparison of isocyanate exposure data between studies and development of occupational exposure limits (OELs) for polyisocyanates is difficult. METHODS: An analysis of existing problems in the measurement and regulation of isocyanates is presented based on the published analytical, toxicological, and regulatory literature, and the authors' own analytical data and experience with isocyanates. RESULTS: This analysis supports a need for standardization of isocyanate measurement metrics and provides a framework for the development of an OEL for polyisocyanates. CONCLUSIONS: The total isocyanate group (microg NCO/m(3)) is recommended as the most feasible and practical metric (unit) by which to express polyisocyanate exposures for research, control, and regulatory purposes. The establishment of a comprehensive isocyanate OEL that simplifies the current agent-by-agent approach and expands coverage to polyisocyanates is also recommended.

Air Pollutants, Occupational↗

Glove use and the relative risk of acute hand injury: a case-crossover study.

The purpose of this study was to investigate the relationship between glove use and acute traumatic occupational hand injury. We used a case-crossover, within-subject study design to control for differences between individuals such as occupation, injury history, age, gender, risk-taking behavior, manual dexterity, and muscle strength. A total of 1166 hand-injured workers were interviewed regarding the use of gloves at the time of the injury. The self-reported average duration of glove use in the previous work month was the measure of expected exposure to wearing gloves. Nineteen percent of subjects reported wearing gloves at the time of the injury. The expected exposure to glove use in the past work month was 27.9%. Glove use was associated with a lower risk of lacerations and punctures but not crush, fractures, avulsions, amputations, dislocations; the risk of the former two injury types was estimated to be 60-70% lower while wearing gloves. Glove use is only one component of a comprehensive hand injury prevention approach that might include the identification and elimination of sharp hazards, engineering controls, safety warnings, training in high-risk situation awareness, and proper selection and timing of glove use.

Acute Disease↗

Is chronic airway obstruction from cotton dust exposure reversible?

BACKGROUND: Exposure to cotton dust is known to cause chronic airway obstruction, but there is little information on whether the obstructive impairment is reversible after the exposure stops. METHODS: Longitudinal changes in lung function were evaluated among 429 cotton textile workers and 449 silk workers in Shanghai, China, beginning in 1981. Both active and retired workers were tested every 4 to 6 years for 15 years. RESULTS: Overall, cotton workers had greater annual declines in forced expiratory volume in 1 second (FEV1) and forced vital capacity (FVC). Compared with active workers, retired cotton workers had lower annual loss of FEV1, although the retired workers had a greater loss during their active employment than the currently active workers. No such trends were detected in silk workers. Annual declines in FEV1 in retired cotton workers were smaller with increasing time since retirement. Multivariate analysis showed that retirement was a substantial contributing factor for improved FEV1 and FVC in the cotton workers, especially among those who did not smoke. Correspondingly, remission of airflow obstruction, defined as a ratio of FEV1 and FVC of less than 70%, was more common in retirees than in the active workers, and more common in nonsmokers than in smokers. CONCLUSION: Chronic airway obstruction related to long-term exposure to cotton dust may be partially reversible after the exposure ceases, although lung function does not return to the level found in unexposed workers.

Adult↗

Temporal factors and the prevalence of transient exposures at the time of an occupational traumatic hand injury.

Temporal factors and the prevalence of exposure to transient risk factors for occupational traumatic hand injury were analyzed among 1166 subjects participating in a case-crossover study. Temporal factors included time of injury and elapsed time to injury since the start of the work shift. Transient exposures included work equipment, work practice, and worker-related factors. The highest frequency of injury was observed from 08:00 am to 12:00 pm (54.6%), with a peak from 10:00 to 11:00 am (14.9%). The median time into the work shift for injury was 3.5 hours. Subjects injured 2 to 3 hours into their work shift most often reported using a machine, tool, or work material that performed differently than usual (23.9%). These results suggest that acute hand injuries occur earlier in the workday and safety programs should place increased vigilance on these times.

Accidents, Occupational↗

Truncating the dose range for methacholine challenge tests: three occupational studies.

The methacholine challenge test protocol was assessed in the reanalysis of three occupational studies. We evaluated the impact of truncating the range of methacholine on responsiveness, as defined by slope and PC(20). In original analysis, reactivity was similar for apprentices and auto body shop workers, whereas boilermakers were more responsive. Truncating high concentrations did not change the classification of subjects with PC(20) <8 or 16 in any population. However, when responsiveness was measured by slope, the mean responsiveness increased, from -7.9 to -15.3 for apprentices and -7.2 to -10.0 for auto-body shop workers. Results support the American Thoracic Society's recommended maximum of 16 mg/ml and provide evidence that extending the dose range beyond that does not increase sensitivity, whereas stopping before 16 may exaggerate response. Furthermore, to ensure validity, neither slope nor PC(20) should be extrapolated beyond data.

Adult↗

Measurement characteristics of peak expiratory flow.

STUDY OBJECTIVES: To evaluate features of the peak expiratory flow (PEF) test protocol, and to characterize patterns of reproducibility in multiple PEF measurements. DESIGN: Cross-sectional study. SETTING: University population. PARTICIPANTS: Two hundred twenty-three healthy adults. INTERVENTIONS: Participants recorded five PEF measurements in each of five sessions per day for 1 week. MEASUREMENTS AND RESULTS: Patterns of within-session variability were characterized using a reproducibility criterion based on a large percentage difference between best trials and evidence of a maneuver-induced bronchospasm (MIB) indicated by successive drops of PEF values in a session. Although the maximum PEF value in a session occurred on the fourth or fifth trial 32% of the time, the change in PEF values was small. Supervision was associated with small improvements in level and reproducibility. Using a cutoff of 5% for defining reproducibility, 15% of all sessions were not reproducible. When averaged over each subject, 9% of the cohort had a mean difference > 5%. Overall, MIB was unusual and observed in 8% of all test sessions; however, MIB was more common among asthmatics and subjects with wheeze, atopy, or allergies than subjects without. By contrast, poor reproducibility was more common among smokers and subjects with cough and phlegm. CONCLUSIONS: These results illustrate that it may be unnecessary to supervise all sessions or collect more than three efforts. Results also suggest that reproducibility reflects smoking-related abnormalities, whereas MIB may reflect airways hyperresponsiveness.

Adult↗

A reliability study of potential risk factors for acute traumatic occupational hand injuries.

BACKGROUND: A reliability study of transient workplace exposures was conducted within a case-crossover study of acute traumatic occupational hand injuries. Exposures examined included features of work equipment (unusual performance of equipment or materials, glove use), work practices (performing an uncommon work task, using an unusual work method), and worker-related factors (being rushed, distracted, ill, or working overtime). METHODS: Interviewers administered a follow-up questionnaire about exposure up to 4 days after the initial interview. The reliability of the usual frequency of exposure in the past month, exposure reported at the time of the injury, and the degree to which subjects had confidence in the accuracy of their memory for exposure was assessed. RESULTS: The test-retest reliability for the estimated number of hours of exposure during the past month was high for six of the eight potential risk factors (intraclass correlation coefficients (ICC) ranging from 0.84-0.99). ICC for the frequency per month and minutes per exposure, used to calculate the estimated number of hours per month, ranged from 0.12-0.99 and 0.49-0.99, respectively. Agreement of reported exposure at the time of the injury, evaluated using the kappa statistic, ranged from substantial agreement to perfect agreement (0.65-1.0). However, for some factors, there was little or no reported exposure. Most subjects (74-100%) reported being "very confident" or "certain" in their memory for each exposure. CONCLUSIONS: These findings suggest that the frequency and duration of unusual transient workplace exposures can be reliably recalled by subjects interviewed by telephone within 4 days of an injury.

Accidents, Occupational↗