Retrospective Cohort Study Of Workers Research Articles

Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS)

Study question Is protracted exposure to low doses of ionising radiation associated with an increased risk of solid cancer?Methods In this cohort study, 308 297 workers in the nuclear industry...

Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS)

Risk of cancer from occupational exposure to ionising radiation: retrospective cohort study of workers in France, the United Kingdom, and the United States (INWORKS)

Mortality from liver cancer and leukaemia among polyvinyl chloride workers in Taiwan: an updated study

ObjectivesTo investigate types of cancer caused by occupational exposure to vinyl chloride monomer (VCM) and the temporal mortality trends of these cancers in workers from polyvinyl chloride (PVC) manufacturing factories...

Abstract 3776: Third follow-up of a Dutch cohort occupationally exposed to chlorophenoxy herbicides, chlorophenols and dioxins

Abstract A retrospective cohort study of workers exposed to phenoxy herbicides, chlorophenols, and contaminants (2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and other polychlorinated dioxins and furans) has been conducted in two chemical factories in the Netherlands. TCDD levels at time of presumed last exposure were estimated based on back-extrapolation of predictive models derived from a cross-sectional survey on a sub-population of the full cohort. Analyses were done using Cox proportional hazard models, using attained age as the time-scale. In analyses relating exposure to phenoxy herbicides to cancer mortality the previously reported increased risks for respiratory cancer, and non-Hodgkin's lymphoma in factory A could not be confirmed. However, increased risks were observed for all cancers in both factory A (HR=1.31; 95% CI 0.86-2.01) and factory B (HR=1.54; 95% CI 1.00-2.37). Increased risks for urinary cancers (HR=4.2; 95% CI 0.99-17.89) and genital cancers (HR=2.93; 95% CI 0.61-14.15) were observed in factory A, consistent with earlier reported results in this population. More detailed analyses showed that this increased risk for urinary and genital cancers in exposed workers was not due to selection of healthy controls and could not be attributed to specific products or departments. The results of this study showed only slight increases in cancer mortality risk among phenoxy herbicide exposed workers. Analyses using estimated (back-extrapolated) TCDD are currently in progress. Preliminary analyses suggest an increased risk for non-Hodgkin lymphoma in TCDD exposed factory A compared to B. Note: This abstract was not presented at the AACR 101st Annual Meeting 2010 because the presenter was unable to attend. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr 3776.

Relationship Between Early Opioid Prescribing for Acute Occupational Low Back Pain and Disability Duration, Medical Costs, Subsequent Surgery and Late Opioid Use

Retrospective cohort study of workers' compensation (WC) claims with acute disabling low back pain (LBP). To examine the association between early opioid use for acute LBP and outcomes: disability duration, medical costs, "late opioid" use (> or = 5 prescriptions from 30 to 730 days), and surgery in a 2-year period following LBP onset. Opioid analgesics have become more accepted for acute pain management. However, treatment guidelines recommend limited opioid use for acute LBP management. Little is known about the long-term impact on outcomes of opioid use for acute LBP. The sample consisted of 8443 claimants from a large WC database with new-onset, disabling LBP that occurred between January 1, 2002 and December 31, 2003. Based on morphine equivalent amount (MEA) in milligrams received in the first 15 days ("early opioids"), claimants were divided into 5 groups (0, 1-140, 141-225, 226-450, 450+). The associations between early opioids and outcomes were evaluated using multivariate linear and logistic regression models. Covariates included age, gender, job tenure, and low back injury severity. Injury severity was classified using ICD-9 codes. Twenty-one percent of claimants received at least 1 early opioid prescription. After controlling for the covariates, mean disability duration, mean medical costs, and risk of surgery and late opioid use increased monotonically with increasing MEA. Those who received more than 450 mg MEA were, on average, disabled 69 days longer than those who received no early opioids (95% confidence interval [CI], 49.2-88.9). Compared with the lowest MEA group (0 mg opioid), the risk for surgery was 3 times greater (95% CI, 2.4-4.0) and the risk of receiving late opioids was 6 times greater (95% CI, 4.9-7.7) in the highest MEA group. Low back injury severity was a strong predictor of all the outcomes. Given the negative association between receipt of early opioids for acute LBP and outcomes, it is suggested that the use of opioids for the management of acute LBP may be counterproductive to recovery.

Estimated effects of solvents and mineral oils on cancer incidence and mortality in a cohort of aerospace workers

A retrospective cohort study of workers employed at a California aerospace company between 1950 and 1993 was conducted; it examined cancer mortality from exposures to the rocket fuel hydrazine. In this study, we employed a job exposure matrix (JEM) to assess exposures to other known or suspected carcinogens-including trichloroethylene (TCE), polycyclic aromatic hydrocarbons (PAHs), mineral oils, and benzene-on cancer mortality (1960-2001) and incidence (1988-2000) in 6,107 male workers. We derived rate- (hazard-) ratios estimates from Cox proportional hazard models with time-dependent exposures. High levels of TCE exposure were positively associated with cancer incidence of the bladder (rate ratio (RR): 1.98, 95% confidence interval (CI) 0.93-4.22) and kidney (4.90; 1.23-19.6). High levels of exposure to mineral oils increased mortality and incidence of lung cancer (1.56; 1.02-2.39 and 1.99; 1.03-3.85), and incidence of melanoma (3.32; 1.20-9.24). Mineral oil exposures also contributed to incidence and mortality of esophageal and stomach cancers and of non-Hodgkin's lymphoma and leukemia when adjusting for other chemical exposures. Lagging exposure measures by 20 years changed effect estimates only minimally. No associations were observed for benzene or PAH exposures in this cohort. Our findings suggest that these aerospace workers who were highly exposed to mineral oils experienced an increased risk of developing and/or dying from cancers of the lung, melanoma, and possibly from cancers of the esophagus and stomach and non-Hodgkin's lymphoma and leukemia. These results and the increases we observed for TCE and kidney cancers are consistent with findings of previous studies.

An increased standardised mortality ratio for liver cancer among polyvinyl chloride workers in Taiwan

Aims: To determine the standardised mortality ratio (SMR) corresponding to different causes of death in workers from polyvinyl chloride polymerisation factories in Taiwan. Methods: Retrospective cohort study of workers from...

The Effects of Internal Radiation Exposure on Cancer Mortality in Nuclear Workers at Rocketdyne/Atomics International

We examined the effects of chronic exposure to radionuclides, primarily uranium and mixed-fission products, on cancer mortality in a retrospective cohort study of workers enrolled in the radiation-monitoring program of a nuclear research and development facility. Between 1950 and 1994, 2,297 workers were monitored for internal radiation exposures, and 441 workers died, 134 (30.4%) of them from cancer as the underlying cause. We calculated internal lung-dose estimates based on urinalysis and whole-body and lung counts reported for individual workers. We examined cancer mortality of workers exposed at different cumulative lung-dose levels using complete risk-set analysis for cohort data, adjusting for age, pay type, time since first radiation monitored, and external radiation. In addition, we examined the potential for confounding due to chemical exposures and smoking, explored whether external radiation exposure modifies the effects of internal exposure, and estimated effects after excluding exposures likely to have been unrelated to disease onset. Dose-response relations were observed for death from hemato- and lymphopoietic cancers and from upper aerodigestive tract cancers, adjusting for age, time since first monitored, pay type, and external (gamma) radiation dose. No association was found for other cancers, including cancers of the lung. Despite the small number of exposed deaths from specific cancer types and possible bias due to measurement error and confounding, the positive findings and strong dose-response gradients observed suggest carcinogenic effects of internal radiation to the upper aerodigestive tract and the blood and lymph system in this occupational cohort. However, causal inferences require replication of our results in other populations or confirmation with an extended follow-up of this cohort.

The effects of internal radiation exposure on cancer mortality in nuclear workers at Rocketdyne/Atomics International.

We examined the effects of chronic exposure to radionuclides, primarily uranium and mixed-fission products, on cancer mortality in a retrospective cohort study of workers enrolled in the radiation-monitoring program of a nuclear research and development facility. Between 1950 and 1994, 2,297 workers were monitored for internal radiation exposures, and 441 workers died, 134 (30.4%) of them from cancer as the underlying cause. We calculated internal lung-dose estimates based on urinalysis and whole-body and lung counts reported for individual workers. We examined cancer mortality of workers exposed at different cumulative lung-dose levels using complete risk-set analysis for cohort data, adjusting for age, pay type, time since first radiation monitored, and external radiation. In addition, we examined the potential for confounding due to chemical exposures and smoking, explored whether external radiation exposure modifies the effects of internal exposure, and estimated effects after excluding exposures likely to have been unrelated to disease onset. Dose-response relations were observed for death from hemato- and lymphopoietic cancers and from upper aerodigestive tract cancers, adjusting for age, time since first monitored, pay type, and external (gamma) radiation dose. No association was found for other cancers, including cancers of the lung. Despite the small number of exposed deaths from specific cancer types and possible bias due to measurement error and confounding, the positive findings and strong dose-response gradients observed suggest carcinogenic effects of internal radiation to the upper aerodigestive tract and the blood and lymph system in this occupational cohort. However, causal inferences require replication of our results in other populations or confirmation with an extended follow-up of this cohort.

A retrospective cohort study of male workers exposed to PVA fibers.

In order to ascertain whether PVA fibers can produce cancer in humans or not, we have conducted a retrospective cohort study of workers exposed to PVA fibers. A total of 447 exposed and 2416 non-exposed male workers who were engaged before 1980 were followed up until the end of 1996. The SMR for all causes was 0.57 (observed 38, 95% CI: 0.41-0.78) for the exposed, and 0.66 (observed 210, 95% CI: 0.58-0.75). As for lung cancer, its SMR was 0.77 (observed 3, 95% CI: 0.15-2.24) for the exposed workers and 0.67 (12 observed, 95% CI: 0.34-1.16) for the non-exposed workers. Lung cancer SMR was 0.86 (observed 2, 95% CI: 0.10-3.11) for the workers with 20 or more years' employment. This study showed no difference in lung cancer risk between the workers exposed to PVA fibers and the non-exposed workers.

Retrospective cohort study of workers of a synthetic textiles plant in quebec: 1. General mortality : M. S. Goldberg and G. Theriault. American Journal of Industrial Medicine, 25(6), 889–907

Retrospective cohort study of workers of a synthetic textiles plant in quebec: 1. General mortality : M. S. Goldberg and G. Theriault. American Journal of Industrial Medicine, 25(6), 889–907

Retrospective cohort study of workers of a synthetic textiles plant in quebec: I. General mortality

This paper presents results from a retrospective cohort study of workers of a synthetic textiles plant in Quebec. This plant has been the subject of a previous case-control study, in which an excess risk of colorectal cancer was observed. The cohort consisted of 7,487 men and 2,724 women who had worked at least 1 year at the plant and who were either working in 1947 or were newly employed between 1947 and 1977. The period of follow-up was from 1947 to 1986, thus yielding 307,278 person-years of observation. Mortality rates for most causes of death were less than expected; the standardized mortality ratio (SMR) for all causes of death among men was 0.73 (95% confidence interval (CI): 0.70-0.77) and among women it was 0.77 (95% CI: 0.68-0.87). For men, the SMR for all neoplasms was 0.76 (95% CI: 0.69-0.83) and for colorectal cancer it was 0.69 (95% CI: 0.52-0.92). For women, the SMR for all neoplasms was 1.01 (95% CI: 0.83-1.22) and for colorectal cancer it was 1.02 (95% CI: 0.57-1.69). Among men, risks for ischemic heart disease increased with increasing length of service at the plant, even though the SMRs were less than unity (overall SMR = 0.76; 95% CI: 0.70-0.83); no trend was observed for women. SMRs and relative risks were also calculated according to duration of employment in each processing unit. Of the scores of associations tested, very few showed increased risks. Of those showing increased risks, the data were not persuasive in indicating a connection with work at the plant; nevertheless, some of these associations may be worth following up in future studies. The following associations of potential significance were observed: all cancers, liver and gallbladder cancers, non-Hodgkin's lymphomas, and reticulum cell sarcoma in the cellulose acetate fiber manufacturing unit; all cancers in the polypropylene and cellulose triacetate extrusion unit and in the janitor unit; leukemias in the unexposed unit; ischemic heart disease in the maintenance and janitor units; and cerebrovascular disease in the weaving unit.

Retrospective cohort study of workers of a synthetic textiles plant in Quebec: II. Colorectal cancer mortality and incidence.

This paper describes standard mortality and nested case-control analyses of colorectal cancer for a cohort of synthetic textiles workers in which a cluster of five cases was observed previously. The cohort consisted of 7,487 men and 2,724 women who had more than 1 year's experience at the plant and who were either working in 1947 or were newly employed between 1947 and 1977. The Standardized Mortality Ratio (SMR) for colorectal cancer for men was 0.69 (95% confidence interval (CI): 0.52-0.92; 50 deaths) and for women it was 1.02 (95% CI: 0.57-1.69; 15 deaths). Among men only there was a suggestion that risks increased according to the length of service at the plant. In the nested case-control study, incident cases as well as deceased cases were included. A variety of analyses were carried out according to duration of employment in the processing units. For men the risk of colon cancer increased with duration of employment in the polypropylene and cellulose triacetate extrusion unit (unadjusted odds ratio (OR) for > or = 5 years duration = 5.52; 95% CI: 1.12-27.26; 4 exposed cases). It was not possible, however, to provide an independent confirmation of this putative association because the case series included three of the original five cases. There was some evidence of increased risks in the cellulose acetate fiber manufacturing unit and in the dyeing and finishing unit, but the data were compatible with the null hypothesis of no effect. No associations were observed for employment in any of the other processing units.

Mortality experience of haematite mine workers in China.

The mortality risk of iron ore (haematite) miners between 1970 and 1982 was investigated in a retrospective cohort study of workers from two mines, Longyan and Taochong, in China. The cohort was limited to men and consisted of 5406 underground miners and 1038 unexposed surface workers. Among the 490 underground miners who died, 205 (42%) died of silicosis and silicotuberculosis and 98 (20%) of cancer, including 29 cases (5.9%) of lung cancer. The study found an excess risk of non-malignant respiratory disease and of lung cancer among haematite miners. The standardised mortality ratio for lung cancer compared with nationwide male population rates was significantly raised (SMR = 3.7), especially for those miners who were first employed underground before mechanical ventilation and wet drilling were introduced (SMR = 4.8); with jobs involving heavy exposure to dust, radon, and radon daughters (SMR = 4.2); with a history of silicosis (SMR = 5.3); and with silicotuberculosis (SMR = 6.6). No excess risk of lung cancer was observed in unexposed workers (SMR = 1.2). Among current smokers, the risk of lung cancer increased with the level of exposure to dust. The mortality from all cancer, stomach, liver, and oesophageal cancer was not raised among underground miners. An excess risk of lung cancer among underground mine workers which could not be attributed solely to tobacco use was associated with working conditions underground, especially with exposure to dust and radon gas and with the presence of non-malignant respiratory disease. Because of an overlap of exposures to dust and radon daughters, the independent effects of these factors could not be evaluated.