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Biomedical subjects

M M Finkelstein

Publications and source records attributed to M M Finkelstein.

At least 55 records · Page 3Linked to original sources

Silicosis surveillance in Ontario: detection rates, modifying factors, and screening intervals.

The Province of Ontario has had a surveillance program for workers in dusty industries for almost 70 years. This paper reports the detection rates of silicosis among 68,701 silica-exposed individuals who were first exposed to dust in 1950 or later, and who were still employed in 1979 or later. The detection rate varied strongly with latency, being less than two new cases per 10,000 examinations during the first two decades from first exposure, reaching two new cases per 1,000 examinations at 27 years from first exposure, and averaging between two and four new cases per 1,000 examinations thereafter. The silicosis incidence rate among miners was only about half that among foundry workers. Cigarette smoking was also found to be a risk factor for the diagnosis of silicosis. These data were used to model the detection rate of new cases of silicosis as a function of the time interval between examinations, and results are presented for examination cycles between 2 and 10 years.

Humans↗

Lung cancer among steelworkers in Ontario.

A population-based case-control study was carried out to follow up observations of increased lung cancer risk in the steel pouring areas of two Ontario steel mills. Study subjects were all men, aged 45-75 years, who died of lung cancer in the cities of Hamilton or Sault Ste-Marie, Ontario from 1979-1988. Nine hundred sixty-seven lung cancer victims were matched with 2,827 control subjects who died of other causes. Work histories were provided by the employers of steelworkers. In comparison with other residents of their cities, the relative risk of death from lung cancer was 0.85 (95% confidence interval [CI]: 0.58-1.23) for steelworkers in Sault-Ste Marie and was 1.10 (95% CI: 0.89-1.37) for steelworkers in Hamilton. In internal comparisons within the steel companies, increased lung cancer risk was observed among foundry, coke oven, and pouring pit workers. Retrospective hygiene assessment suggested that the increased risk of lung cancer among steel pourers might be related to the use of tar-based mold coating agents or to exposure to mineral fibers.

Aged↗

Increased risk of lung cancer in the melting department of a second Ontario steel manufacturer.

A study of lung cancer among workers at an electric arc steel making operation was performed to follow up on the observation of a lung cancer cluster in the melt shop of another plant. The study group comprised 335 deceased men identified from plant records. Eight of thirty men who had ever worked in the pouring pit area died of lung cancer (PMR 276; p less than 0.01), but increased risk was not found elsewhere in the melting department. There was a significant trend in lung cancer risk with the length of employment in the pit area during a time window 18-30 years before death. Smoking data suggested that smoking alone could not account for the increased risk. An industrial hygiene assessment found present exposures to carcinogenic metals and silica to be within current guidelines. No polycyclic aromatic hydrocarbons were detected. This is the second steel plant for which we have found increased lung cancer risk in the pouring areas. The causative factors have not yet been identified.

Case-Control Studies↗

Use of "time windows" to investigate lung cancer latency intervals at an Ontario steel plant.

This paper describes an application of the time windows method to an examination of the temporal pattern of lung cancer risk among steel workers. Case-control methodology was utilized. The cases were 36 men who had died of lung cancer and the controls were 289 men who had died of any other cause. The number of years of employment in the steel pouring area was used as a surrogate measure of exposure. The data were examined by contingency table analysis and by logistic regression, which permitted adjustment for exposures in multiple time windows and the use of continuous, rather than categorical, measures of exposure. It was found that lung cancer risk was associated with exposures occurring between 18 and 30 years before death. It cannot yet be determined whether this time course reflects a biological response or the temporal pattern of exposure to an as yet unidentified toxic agent.

Case-Control Studies↗

Investigation of a lung cancer cluster in the melt shop of an Ontario steel producer.

Workers' concerns about an excess of cancer in an electric arc steelmaking operation were investigated. In comparison with men who had worked elsewhere in the plant, an increased risk of lung cancer death was observed among men who had been employed in the melt shop. The hypothesis that the association might be related to occupational exposures is supported by the persistence of the association when the hypothesis-generating cases were removed from the analysis (p = 0.063) and by a significant trend in the risk of lung cancer with years of exposure in the melt shop. No air sampling had been performed in earlier years. Current environmental analyses in the melt shop found no polycyclic aromatic hydrocarbons (detection limit: 0.001 mg/m3), and silica levels were below 0.1 mg/m3. The carcinogenic metals arsenic and chromium were detected, but their concentrations in earlier years are unknown.

Alloys↗

Mortality rates among employees potentially exposed to chrysotile asbestos at two automotive parts factories.

A study of the mortality rates among 1657 employees at two Ontario automotive parts factories that manufactured friction materials containing chrysotile asbestos was initiated in response to the workers' concerns about the effects of asbestos on their health. A total of 1194 men and 258 women had had their first potential exposure at least 10 years before the end of the study period; 563 of the men and 138 of the women had had such an exposure at least 20 years before the end of the study period. A significantly increased rate of death from laryngeal cancer and an elevated rate of death from lung cancer were observed in a cohort analysis. One or two deaths might have been due to pleural mesothelioma. There was no increase in the rate of death from gastrointestinal cancer or from nonmalignant respiratory disease. Case-control analysis showed no association between the risk of laryngeal or lung cancer and the total duration of employment (a surrogate for the extent of ambient exposure to asbestos or other workplace toxic substances) or employment in departments where asbestos had been used. An association between risk of death and occupational exposure is uncertain.

Adult↗

Mortality among employees of an Ontario factory manufacturing insulation materials from amosite asbestos.

The mortality of workers from an Ontario factory manufacturing amosite asbestos insulation materials under poorly controlled environmental conditions is reported here. Seven (58%) of 12 deaths among exposed workers 10 or more years after first exposure were due to malignancies; four (25%) were from lung cancer, and there were two deaths from peritoneal mesothelioma. Those dying from mesothelioma were 47 and 49 years of age. Three (25%) of 12 deaths were from respiratory disease, two were attributed to asbestosis (in men 42 and 53 years of ages), and one to pneumonia in a 54-year-old male.

Asbestosis↗

Mortality among employees of an Ontario factory that manufactured construction materials using chrysotile asbestos and coal tar pitch.

This paper describes mortality in a cohort of 324 men exposed to chrysotile asbestos and coal tar pitch used in the manufacture of electrical conduit pipe from a mixture of newsprint, bentonite, and asbestos. One death in a factory worker was attributed to pleural mesothelioma, and long-term employees experienced an increased risk of lung cancer (Standardized Mortality Ratio (SMR) 221; six deaths) and non-malignant respiratory disease (SMR 215; four deaths). In a case-control analysis, men whose jobs involved adding asbestos to the mix of raw materials were found to have a risk of lung cancer sevenfold higher (lower 95% confidence limit: 2.3) than men who had never worked at this job. Exposure to coal tar pitch is presumed to be responsible for the death of one worker from squamous cell carcinoma of the scrotum.

Adult↗

Analysis of mortality patterns and workers' compensation awards among asbestos insulation workers in Ontario.

Mortality and workers' compensation patterns were studied among 1,064 Ontario asbestos insulation workers. A proportional mortality analysis of 153 asbestos worker deaths found increased mortality from malignant diseases (65 deaths observed; 35.1 expected), cancers of the lungs and pleura (32 deaths observed; 11.5 expected), peritoneal mesothelioma (4 deaths), and respiratory diseases (14 deaths observed; 7.9 expected). Despite the publicity given to asbestos-associated diseases, dependents of many men potentially eligible for workers compensation awards have not received pensions because claims were not filed. These findings suggest that much occupationally related disease is not being recognized in Ontario.

Asbestos↗

Nasal cancer among North American woodworkers: another look.

A death certificate case-control study of sinonasal cancer in Ontario has found increased relative risks among wood-workers. The results from four North American studies have been combined using the Mantel-Haenszel method, and the relative risk for woodworkers has been found to be 1.6 (P less than .01). It is concluded that North American softwoods, as well as hardwoods, may contain carcinogenic substances or their precursors.

Adult↗

Selection bias in occupational case-control studies that use death registries to select subjects: a discussion and demonstration.

Some epidemiologic studies have selected subjects from death registries. This method is, however, subject to substantial systematic bias that arises from the fact that different segments of society have different risks of death in any year. Different occupational groups will thus have unequal probabilities of entering the pool of potential controls, and biased estimates of the odds ratios that relate occupation to disease will result. Failure to recognize the bias may lead to invalid conclusions. This selection bias is discussed, with particular reference to studies of malignancies among farmers. The bias is demonstrated by using data from studies of Parkinson's disease and sinonasal cancer.

Aged↗

A study of dose-response relationships for asbestos associated disease.

The risk of an asbestos worker developing small irregular opacities on the chest radiograph is related to cumulative exposure to asbestos dust, latency, and smoking habit. In this study the use of residence-time weighted exposure as a "dose metric" was explored in a cohort of asbestos cement workers. It was found that this parameter, which incorporates both exposure concentration and latency, is useful for modelling the risk of small opacities and might also be useful for modelling the risk of mesothelioma.

Adolescent↗