Cohort studies of chloroprene-exposed workers in Russia.

Two retrospective cohort studies were conducted to assess the risk of cancer among workers exposed to chloroprene (2-chloro-1,3-butadiene) (CP). One is a study of incidence and mortality among 2314 production workers employed in the CP production plant in Yerevan, Armenia, between 1940 and 1988. The cohort was followed up for cancer incidence for the years 1979-1990 and for cancer mortality for 1979-1988. The second study is a mortality study among 5185 shoe manufacturing workers in Moscow who used polychloroprene latex and glue. Shoe workers were employed between 1940 and 1976, and followed from 1979 through 1993. The standardized incidence ratios (SIR) and standardized mortality ratios (SMR) were calculated using the Armenian and Moscow population as reference. An internal comparison analysis based on Poisson regression modeling was conducted. In the Yerenan cohort, incidence and mortality from all cancers were below expectation, but increased incidence (SIR, 3.27; 95% confidence interval (CI), 1.47-7.27), and mortality (SMR, 3.39; CI, 1.09-10.5) from liver cancer were noted. A dose-response relationship was suggested between the risk of liver cancer and indices of CP exposure. For the entire Moscow cohort, all-cause mortality was close to expectation and all-cancer mortality was increased. There was an increase in the mortality from liver cancer (SMR, 2.4; CI, 1.1-4.3), kidney cancer (SMR, 1.8; CI, 0.9-3.4), and leukemia (SMR, 1.9; CI, 1.0-3.3). Mortality from liver cancer and leukemia was associated with various indicators of CP exposure. A similar, although less consistent, pattern was found for kidney cancer. The association between CP exposure and risk of leukemia may be due to concomitant exposure to benzene. The results for liver cancer point towards a carcinogenic effect of CP.

Mortality from cardiovascular diseases and exposure to inorganic mercury.

OBJECTIVE: To study the mortality from cardiovascular and other chronic non-neoplastic diseases after long term exposure to inorganic mercury. Limited information is available on the effect of chronic exposure to mercury on the cardiovascular system. METHODS: The mortality was studied among 6784 male and 265 female workers from four mercury mines and mills in Spain, Slovenia, Italy, and the Ukraine. Workers were employed between 1900 and 1990; the follow up period lasted from the 1950s to the 1990s. The mortality of the workers was compared with national reference rates. RESULTS: Among men, there was a slight increase in overall mortality (standardised mortality ratio (SMR) 1.08, 95% confidence interval (95% CI) 1.04 to 1.12). An increased mortality was found from hypertension (SMR 1.46, 95% CI 1.08 to 1.93), heart diseases other than ischaemic (SMR 1.36, 95% CI 1.20 to 1.53), pneumoconiosis (SMR 27.1, 95% CI 23.1 to 31.6), and nephritis and nephrosis (SMR 1.55, 95% CI 1.13 to 2.06). The increase in mortality from cardiovascular diseases was not consistent among countries. Mortality from hypertension and other heart diseases increased with estimated cumulative exposure to mercury; mortality from ischaemic heart disease and cerebrovascular diseases increased with duration of employment, but not with estimated exposure to mercury. Results among women were hampered by few deaths. CONCLUSION: Despite limited quantitative data on exposure, possible confounding, and likely misclassification of disease, the study suggests a possible association between employment in mercury mining and refining and risk in some groups of cardiovascular diseases.

Cancer mortality among women in the Russian printing industry.

BACKGROUND: This study evaluates cancer mortality among women employed in two large printing plants in Moscow. METHODS: A total of 3,473 women who were actively employed as of December 31, 1978, with a minimum of 2 years employment were followed from 1 January 1979 to 31 December 1993. There were 47,791 person-years observed, with only 51 women lost to follow-up (1.5%). Standardized mortality ratios (SMRs) were calculated using the population of Moscow to generate expected numbers. Analyses by job (compositors, press operators, and bookbinders), age hired, latency, and duration of employment were conducted. RESULTS: Among women employed in the two printing plants, there was a significant excess of esophageal cancer, based on seven deaths (expected = 2.7, SMR = 2.7, 95% CI = 1.1-5.4). Four of the seven esophageal cancer deaths occurred among bookbinders (expected = 1.0, SMR = 4.1, 95% CI = 1.1-10.4), all among workers hired before 1957 (expected = 0.6, SMR = 7.1, 95% CI = 1.9-18.3), the last year benzene was used in bookbinding. Ovarian cancer was also significantly elevated among bookbinders (12 observed, 4.2 expected, SMR = 2.9, 95% CI = 1.5-5.0), which, along with one death from mesothelioma of the abdomen, might be related to the use of asbestos-contaminated talc fillers in paper. Press operators had significantly elevated mortality from stomach cancer (observed = 9, expected = 4.1, SMR = 2.2, 95% CI = 1.0-4.2) and, based on two deaths each, melanoma and bladder cancer. CONCLUSIONS: Women in this printing industry cohort experienced excess mortality of cancer of the esophagus and stomach, with suggested increases of melanoma and bladder cancer. Further follow-up of this cohort, which would allow more in-depth analysis of rare cancer sites, latency, and duration of employment, is warranted. Gender comparisons within the cohort should also be conducted to clarify the role of occupational and lifestyle factors in the etiology of cancer among workers in the printing industry.

Occupational cancer in the European part of the Commonwealth of Independent States.

Precise information on the number of workers currently exposed to carcinogens in the Commonwealth of Independent States (CIS) is lacking. However, the large number of workers employed in high-risk industries such as the chemical and metal industries suggests that the number of workers potentially exposed to carcinogens may be large. In the CIS, women account for almost 50% of the industrial work force. Although no precise data are available on the number of cancers caused by occupational exposures, indirect evidence suggests that the magnitude of the problem is comparable to that observed in Western Europe, representing some 20,000 cases per year. The large number of women employed in the past and at present in industries that create potential exposure to carcinogens is a special characteristic of the CIS. In recent years an increasing amount of high-quality research has been conducted on occupational cancer in the CIS; there is, however, room for further improvement. International training programs should be established, and funds from international research and development programs should be devoted to this area. In recent years, following privatization of many large-scale industries, access to employment and exposure data is becoming increasingly difficult.

Cancer incidence and mortality in a cohort of chloroprene workers from Armenia.

We evaluated the risk of cancer among 1897 men and 417 women exposed to chloroprene (2-chloro-1,3-butadiene, CP) at a production plant in Yerevan, Armenia, between 1940 and 1988. The cohort was followed up for cancer incidence for the years 1979-1990 and for cancer mortality for 1979-1988. In the cohort, incidence and mortality from all cancers were below expectation, but increased incidence (standardized incidence ratio 3.27, 95% confidence interval [CI] 1.47-7.27), and mortality (standardized mortality ratio 3.39, 95% CI 1.09-10.5) from liver cancer were noticed. A dose-response relationship was suggested between liver cancer and indices of CP exposure, such as duration of employment, duration of high CP exposure and cumulative exposure to CP. The risk of other neoplasms was not increased.

Cancer mortality among Moscow shoe workers exposed to chloroprene (Russia).

OBJECTIVES: To assess the risk of cancer among workers of a Moscow (Russia) shoe factory exposed to chloroprene (2-chloro-1,3-butadiene) (CP). METHODS: This is a retrospective cohort mortality study among 5,185 shoe manufacturing workers employed between 1940 and 1976, and followed from 1979 through 1993. Exposure to CP was assessed by linking the job history with industrial hygiene data. We calculated standardized mortality ratios (SMR) using the Moscow population as reference, and conducted an internal comparison analysis based on Poisson regression modeling. RESULTS: For the entire cohort, all-cause mortality was close to expectation and all-cancer mortality was increased. There was an increase in the mortality from liver cancer (SMR = 2.4, 95 percent confidence interval [CI] = 1.1-4.3), kidney cancer (SMR = 1.8, CI = 0.9-3.4), and leukemia (SMR = 1.9, CI = 1.0-3.3). Mortality from liver cancer and leukemia was associated with various indicators of CP exposure. A similar, although less consistent, pattern was found for kidney cancer mortality; while for the remaining neoplasms, no association was suggested with CP exposure. CONCLUSIONS: The association between CP exposure and risk of leukemia may be due to concomitant exposure to benzene. The results for liver cancer point towards a carcinogenic effect of CP.

Cancer occurrence among European mercury miners.

OBJECTIVES: To study the carcinogenicity of inorganic mercury in humans. METHODS: We studied the mortality from cancer among 6784 male and 265 female workers of four mercury mines and mills in Spain, Slovenia, Italy and the Ukraine. Workers were employed between the beginning of the century and 1990; the follow-up period lasted from the 1950s to the 1990s. We compared the mortality of the workers with national reference rates. RESULTS: Among men, there was no overall excess cancer mortality; an increase was observed in mortality from lung cancer (standardized mortality ratio [SMR] 1.19, 95 percent confidence interval [CI] 1.03-1.38) and liver cancer (SMR 1.64, CI 1.18-2.22). The increase in lung cancer risk was restricted to workers from Slovenia and the Ukraine: no relationship was found with duration of employment or estimated mercu ry exposure. The increase in liver cancer risk was present both among miners and millers and was stronger in workers from Italy and Slovenia: there was a trend with estimated cumulative exposure but not with duration of employment, and the excess was not present in a parallel analysis of cancer incidence among workers from Slovenia. No increase was observed for other types of cancer, including brain and kidney tumours. Among female workers (Ukraine only), three deaths occurred from ovarian cancer, likely representing an excess. CONCLUSIONS: Exposure to inorganic mercury in mines and mills does not seem strongly associated with cancer risk, with the possible exception of liver cancer; the increase in lung cancer may be explained by co-exposure to crystalline silica and radon.

Mortality in a cohort of Russian fertilizer workers.

OBJECTIVES: The study evaluated the mortality of workers exposed to precursors of N-nitroso compounds in a Russian fertilizer plant. METHODS: Workers employed at least two years between 1945 and 1985 in production departments or other services were included in the cohort, which comprised 2039 men and 2957 women followed from 1965 to 1990. The standardized mortality ratios (SMR) were calculated using cause-specific death rates for the Moscow region as reference. An internal comparison was carried out using Poisson regression modeling. Exposure to arsenic, nitrogen oxides, and sulfur dioxide was estimated from an industrial hygiene survey. RESULTS: The production and other workers had no excess of mortality from all causes or all neoplasms. However the male production workers had excess mortality from all cancers combined (SMR 143) and lung cancer (SMR 186) after a latency period of > or = 20 years. Men with the highest exposure to nitrogen oxides had a twofold increase in mortality from stomach cancer, with a marginally significant increasing trend between stomach cancer and cumulative exposure to nitrogen oxides for both genders. Excess mortality from all cancers and stomach cancer was found for the worker with the highest average exposure to arsenic, and excess lung cancer mortality could be attributed to exposure to arsenic. CONCLUSIONS: The investigation showed a weak association between employment in a fertilizer production plant and increased mortality from cancer. The results somewhat support the hypothesis that occupational exposure to precursors of N-nitroso compounds increases the risk of stomach cancer mortality, as does exposure to arsenic.

Cancer incidence and mortality among beta-naphthylamine and benzidine dye workers in Moscow.

BACKGROUND: Cancer incidence and mortality were evaluated among 4581 aniline dye production workers in Moscow. METHODS: A historical cohort was assembled and followed-up from 1 January 1975 to 31 December 1989. Moscow district oncologic dispensary registries furnished case ascertainment and employer records provided job exposure data. Expected cancers and deaths were calculated based on gender-, age-, and calendar time-specific incidence and mortality rates for the Moscow general population applied to the cohort's person-years of follow-up. Disease-specific standardized mortality and incidence values were derived from ratios of observed to expected cancers. RESULTS: Men experienced elevated total cancer mortality (standardized mortality ratio [SMR] = 125; 95% CI: 110-142) and urinary bladder cancer mortality (SMR = 279; 95% CI: 192-391), and increased all malignancy (standardized incidence ratio [SIR] = 142; 95% CI: 125-160), oesophageal (SIR = 203; 95% CI: 108-347), respiratory tract (SIR = 154; 95% CI: 120-194) and bladder (SIR = 394; 95% CI: 268-559) cancer incidence. Women had elevated oesophageal (SMR = 313; 95% CI: 124-664) and bladder (SMR = 311; 95% CI: 149-571) cancer mortality and elevated all malignancy (SIR = 124; 95% CI: 106-144), oesophageal (SIR = 348; 95% CI: 140-719), and bladder (SIR = 861; 95% CI: 458-8002) cancer incidence. Bladder cancer rate increased with employment duration and younger age first hired. Rate estimates were highest among beta-naphthylamine exposed workers but was also increased among workers with other chemical exposures. A cancer prevention and control effort that limited benzidine exposure to < or = 3 years was apparently unsuccessful as indicated by a significant excess of bladder cancer (SIR = 1773; 95% CI: 356-5180) among these workers. CONCLUSION: Relative rates of oesophageal, lung, and stomach cancer were also elevated among all workers, but did not increase with total years worked, age first hired, or year first hired, suggesting a non-occupational aetiology.

Occupational cancer mortality among urban women in the former USSR.

Occupational cancer mortality was evaluated among approximately three million female pensioners from urban areas of the former USSR. In 1970, these women experienced 14,918 cancer deaths. Occupational data were obtained from death certificates and the 1970 USSR National Population Census. Thirty-five occupational groups, including nine predominantly professional or office-work groups and 26 groups involving physical labor, were evaluated. The expected mortality rates were based on the urban female population of the USSR in 1970. Data for all cancer sites combined, and cancers of the esophagus, stomach, colon, rectum, lung, breast, cervix, and hematopoietic system are presented. Among all female pensioners, there were significant increases of all cancers combined (rate ratio [RR] = 1.05), and cancers of the breast (RR = 1.3), cervix (RR = 1.3), and the hematopoietic system (RR = 1.2), and a significant deficit of cancer of the esophagus (RR = 0.8). Many well-established associations between cancer and occupation among men were observed among the study group of female pensioners, such as stomach and lung cancer among miners, and hematopoietic malignancies among scientists and physicians. Other associations, to be investigated further, also were observed, such as excess lung cancer among waitresses. The peak employment period for this cohort of women was during World War II and the postwar period, when Soviet women outnumbered men almost two-to-one. Consequently, many of the women held jobs that are typically held by men. Thus, this study provides valuable information on occupational risks to women that may be relevant in other countries where women increasingly are being employed in jobs traditionally held by men.