Cohort mortality studies

Spirtas R, Stewart PA, Lee JS, et al. 1991. Retrospective cohort mortality study of workers at an aircraft maintenance Facility 1. Epidemiological results. Br J Ind Med 515-530. 

Mortality studies for workers exposed occupationally to lead are available. These studies all report discrepant results, and all are limited with respect to study design. Therefore, no firm conclusions regarding cause and effect can be drawn from these studies relative to a minimum lethal dose. A cohort mortality study of employees at lead-producing facilities was conducted (Cooper 1988 Cooper et al. 

One cohort mortality study (Fanning 1988) has reported an increased mortality rate due to circulatory disease, but three others found no such correlation (Cooper 1988 Gerhardsson et al. 1986b, 1995a) as discussed in Section 2.2.1.1 (Table 2-1). An increased risk of death due to cerebrovascular disease was observed in a cohort of 1,261 white male newspaper printers (typesetters) (Michaels et al. 1991) (see Section 2.2.1.1). 

A cohort mortality study was conducted to compare the mortality rates due to chronic renal disease in 4,519 battery plant workers and 2,300 lead production or smelter workers from 1947 to 1980 (Cooper 1988 Cooper et al. 1985). The mortality data for these workers were compared with national mortality rates for white males. Environmental lead levels and PbB levels were available for only about 30% of all workers for varying time periods from 1947 to 1972. Statistically significant increases in mortality from "other hypertensive disease" and "chronic nephritis" were seen in both lead cohorts. Limitations of this study include the fact that various confounding factors, such as smoking, were not accounted for, and the workers were probably exposed to other toxic chemicals. 

In a historical cohort mortality study of 1,990 primary lead smelter workers, an SMR of 2.04 for mortality from renal cancer was calculated (Selevan et al. 1985). The cohort consisted of workers who had worked at least 1 year, with at least 1 day of employment at the smelter between 1940 and 1965. The cohort had been heavily exposed to lead and in 1976 the PbB levels averaged 56.3 pg/dL. Exposures to cadmium and arsenic were generally minor. A follow-up study of this cohort was conducted from 1977 through 1988 (Steenland et al. 1992). Analysis of the follow-up study revealed an excess of kidney cancer, particularly in the high-lead group (SMR 2.39). Although, as the authors indicate, the study is... 

Cardiovascular Effects. In a cohort mortality study of workers in a large rubber and tire manufacturing plant, Wilcosky and Tyroler (1983) found a significant increase in mortality from ischemic heart disease in phenol exposed workers. Of the 25 solvents used in the plant, phenol exposure showed the strongest association with mortality from heart disease, greater even than that observed for exposure to carbon disulfide, the only known occupational cause of atherosclerosis. 

In a cohort-mortality study of workers from five phenol-formaldehyde resin plants, Dosemeci et al. 

Similar to the findings of Kauppinen et al. (1986), a large (14,861) cohort mortality study of workers in the phenol-formaldehyde resin manufacturing industry found nondose-related increases in the risk of... 

Whorton MD, Amsel J, Mandel J Cohort mortality study of prostrate cancer among chemical workers. Am J Ind Med 33(3) 293-296, 1998... 

Steenland K, Ward E Lung cancer incidence among patients with beryllium disease a cohort mortality study. J Natl Cancer Inst 83 1380-1385, 1991... 

In humans, cases of hepatomas have appeared years after acute exposure to carbon tetrachloride, however, none of the cases could establish a causal link between the exposure and development of neoplasms." Epidemiological studies have also given inconclusive results. A cancer mortality study of a population of rubber workers reported a significantly elevated odds ratio relating carbon tetrachloride with lymphatic leukemia, and lymphosarcoma and reticulum cell carcinoma." A recent retrospective cohort mortality study of aircraft maintenance workers found an increased risk of... 

An update of a retrospective cohort mortality study of 2588 US workers exposed to PCBs in two capacitor manufacturing plants found a statistically significant excess for cancer of the liver and biliary passages [5 observed vs. 1.9 expected, standardized mortality ratio (SMR) 263]. Both Aroclor 1254 (54% chlorine) and 1242 (42% chlorine) had been used at... 

Two Russian studies suggested an increased incidence of lung and skin cancers in chloroprene-exposed workers compared with a variety of control groups." A more recent retrospective cohort mortality study among Russian shoe factory workers found an increase in the mortality from liver cancer that was associated with chloroprene exposure." A US study of cancer mortality among two cohorts of... 

A cohort study of 5668 NG-exposed workers found an increased standardized mortality ratio for deaths from ischemic heart disease. The increase was more pronounced for those with 10 or more years of exposure and was statistically significant for the 40- to 49-year age group, whereas a deficit of cardiovascular mortality had been anticipated because of preplacement and annual medical examinations designed to exclude persons with cardiovascular abnormalities. These results were confirmed in a retrospective cohort mortality study that found a significant excess of ischemic heart disease mortality among workers actively exposed to NG and under the age of 45. ° (Note this study failed to detect a chronic cardiovascular effect as excess risk was only associated with workers actively exposed to NG.)... 

Band PR, Le ND, Fang R, et al. 1997. Cohort mortality study of pulp and paper mill workers in British Columbia, Canada. Am J Epidemiol 146(2) 186-194. 

Eisen et al. (1992) performed a cohort mortality study of 46 384 workers employed for three or more years before 1985 in three United States auto parts manufacturing facilities. Exposure to all three types of metalworking fluid (straight oils (insoluble or cutting oils), soluble oils (water-miscible or emulsifier oils) and synthetic oils (chemical fluids, containing ethanolamines)), the last two introduced in the 1940s, existed and no... 

Gibbs, G.W., Amsel, J. Soden, K. (1996) A cohort mortality study of cellulose triacetate-fiber workers exposed to methylene chloride. J. occup. environ. Med., 38, 693-697... 

Blair et al. (1998) performed a retrospective cohort mortality study of 14 457 workers employed for at least one year between 1952 and 1956 at an aircraft maintenance facility in the United States. Among this cohort were 6737 workers who had been exposed to carbon tetrachloride (Stewart et al., 1991). The methods used for this study are described in greater detail in the monograph on dichloromethane. An extensive exposure assessment was performed to classify exposure to trichloroethylene quantitatively and to classify exposure (ever/never) to other chemicals qualitatively (Stewart et al., 1991). Risks from chemicals other than trichloroethylene w ere examined in a Poisson regression analysis of cancer incidence data. Among women, exposure to carbon tetrachloride was associated with an increased risk of non-Hodgkin lymphoma (relative risk (RR), 3.3 95% CI,... 

Brown (1992) conducted a cohort mortality study of workers employed at four pesticide manufacturing plants. The 1158 workers employed at Plant 3 of the study, which produced aldrin and dieldrin, were also potentially exposed to l,2-dibromo-3-chloropropane produced at the plant between 1975 and 1976. The cohort included all white males employed for six or more months before 1964 with follow-up through 1987. Although overall cancer mortality at Plant 3 was not elevated (SMR, 0.9 95% Cl, 0.7-1.1 = 72), an excess of liver and biliary tract cancer was observed (SMR, 3.9 95% Cl, 1.3-9.2 5 observed). All of the deaths occurred at least 15 years after first employment (SMR, 4.9), but no association was observed with duration of employment. The SMR for lung cancer was 0.7 (95% Cl, 0.4-1.0). Levels of exposure were not reported. Amoateng-Adjepong et al. (1995) reported the results of an update of the same cohort with three additional years of follow-up. No new association was reported. 

Several studies have examined mortality or cancer incidence among chemical workers potentially exposed to 1,2-dichlorocthanc. Hogstedt et al. (1979) performed a cohort mortality study of 175 Swedish ethylene oxide production workers followed from 1961 through 1977. The workers had been employed for at least one year and were potentially exposed to... 

Austin, S.G Schnatter, A.R. (1983a) A cohort mortality study of petrochemical workers. J. occup. Med., 25, 304-312... 

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